CN117042665A

CN117042665A - Cleaning head and wet cleaning device comprising same

Info

Publication number: CN117042665A
Application number: CN202380010437.0A
Authority: CN
Inventors: B·J·德维特; W·维塞玛; F·R·沃尔霍斯特
Original assignee: Philips Home Appliance Holding Co ltd
Current assignee: Philips Home Appliance Holding Co ltd
Priority date: 2022-01-11
Filing date: 2023-01-09
Publication date: 2023-11-10
Also published as: CN116897003A; CN116867411A; CN116897004A; EP4209163A1; CN116897002A

Abstract

A cleaning head (100) for a wet cleaning device is provided. The cleaning head has at least one cleaning liquid outlet (104) through which cleaning liquid can be delivered. The cleaning liquid applicator material (126, 128) is, for example, adjacent to at least one cleaning liquid outlet. The cleaning liquid applicator material is arranged to apply a cleaning liquid to a surface to be cleaned. The cleaning head also has at least one dirty inlet (142A) and a porous material covering the at least one dirty inlet. The porous material includes a layer of porous material (114) sealingly attached to the at least one dirty inlet. In one aspect, the cleaning liquid applicator material is deformable to bring at least a portion of the cleaning liquid applicator material into contact with the porous material. In another aspect, an edge portion (134) of the porous material abuts an opposing edge portion (136) of the cleaning liquid applicator material. These aspects provide an alternative solution to the same problem of controlling the humidity of the cleaning liquid applicator material. A wet cleaning apparatus including a cleaning head is also provided.

Description

Cleaning head and wet cleaning device comprising same

Technical Field

The present invention relates to a cleaning head for a wet cleaning device and a wet cleaning device comprising a cleaning head. The cleaning head/wet cleaning device may be used, for example, to clean floors, indoor surfaces or windows.

Background

Wet cleaning devices, such as wet mopping apparatus, are known for removing water from a surface to be cleaned. Such wet cleaning devices may also apply a cleaning liquid, such as water, to the surface to be cleaned, and then remove the liquid, such as with a suitable cloth.

Some wet cleaning devices have a power pick-up function for removing water from the surface to be cleaned. For example, a wet vacuum cleaner may draw liquid by creating a sufficient space velocity (e.g., at least 10 m/s) and/or brushing force to exert sufficient shear force on the liquid droplets to cause the droplets to enter the device. Typical power consumption values for such vacuum cleaners are relatively high, for example in the order of a few hundred watts.

Further challenges arise when wet cleaning devices are arranged to deliver cleaning liquid and suction is used to draw the liquid. In at least some designs, providing both functions may present a risk of inefficient use of the cleaning liquid.

During use or even after use, there may also be a risk that the poorly controlled delivery of the cleaning liquid results in the environment becoming wetted with the cleaning liquid. In at least some cases, particularly when a relatively low power pick-up system is employed, such soaking of the surface to be cleaned may not be readily addressed by the pick-up function of the device.

In some designs, the pick-up function may also risk impeding the movement of the cleaning head of such wet cleaning devices over the wet surface to be cleaned.

Disclosure of Invention

The invention is defined by the claims.

According to an example in accordance with one aspect of the present invention, there is provided a cleaning head for a wet cleaning apparatus, the cleaning head having: at least one cleaning liquid outlet through which cleaning liquid can be delivered; a cleaning liquid applicator material arranged to apply the cleaning liquid to a surface to be cleaned; at least one dirty inlet; and a porous material covering the at least one dirty inlet, the porous material comprising a layer of porous material sealingly attached to the at least one dirty inlet, wherein the cleaning liquid applicator material is deformable to bring at least a portion of the cleaning liquid applicator material into contact with the porous material.

The porous material layer sealingly attached to the dirty inlet(s) may help to maintain an under-pressure in the dirty inlet(s) with or without the application of flow, for example by an under-pressure generator included in the wet cleaning apparatus.

The porous material may be arranged to contact a liquid on the surface to be cleaned.

The porous material may, for example, comprise a porous fabric and/or a porous foam. The porous fabric may be, for example, a microfiber fabric.

The surface tension of the liquid retained in the pores of the porous material may help to maintain the under-pressure. The surface tension may be overcome, which means that the air-liquid surface is removed at a point (or points) on the exterior of the porous material that is in contact with the liquid on the surface to be cleaned, such that the liquid is transported through the porous material in the direction of the dirty inlet(s).

By enabling the cleaning liquid applicator material to deform so that at least a portion of the cleaning liquid applicator material is in contact with the porous material, some cleaning liquid can be transferred from the cleaning liquid applicator material to the porous material and into the dirty inlet(s) in a particularly controlled manner. In this way, excessive wetting of the surface to be cleaned may be minimized, for example by dripping cleaning liquid from the cleaning liquid applicator material onto the surface to be cleaned. Alternatively or additionally, by deforming the cleaning liquid applicator material such that at least a portion of the cleaning liquid applicator material contacts the porous material, the cleaning liquid in the latter can be used to effectively rinse the porous material covering the dirty inlet(s).

In at least some embodiments, the cleaning liquid applicator material is configured to deform upon contact with a surface to be cleaned and/or upon wetting by a liquid (e.g., water).

Such wetting may be the result of the cleaning liquid being delivered from the cleaning liquid outlet(s) to the cleaning liquid applicator material and/or as a result of the presence of liquid on the surface to be cleaned.

In a non-limiting example, the cleaning liquid applicator material includes tufts formed from fibers and a backing layer supporting the tufts. Such tufts can deform to contact the porous material, for example, upon contact with a surface to be cleaned and/or upon wetting by a liquid (e.g., water).

While the tufts remain in contact with the porous material, cleaning liquid can be transferred from the cleaning liquid applicator material to the porous material via the tufts and into the soil inlet(s).

In some embodiments, the cleaning liquid applicator material is deformable to bring the edge portion of the cleaning liquid applicator material into contact with the porous material.

For example, when the cleaning liquid applicator material is deformed to bring the edge portion of the cleaning liquid applicator material into contact with the porous material, the edge portion of the cleaning liquid applicator material may abut an opposing edge portion of the porous material.

In some embodiments, the edge portion of the cleaning liquid applicator material is arranged to contact the surface to be cleaned at least when the cleaning liquid applicator material is deformed to bring the edge portion of the cleaning liquid applicator material into contact with the porous material. Thus, the humidity of the cleaning liquid applicator material can be controlled where the cleaning liquid applicator material contacts the surface to be cleaned, thereby minimizing the risk of excessive wetting of the surface to be cleaned.

In a non-limiting example, the cleaning liquid applicator material is deformable to bring at least a portion of the cleaning liquid applicator material into contact with the porous material layer of the porous material. In examples where the porous material comprises one or more further porous material layers, deformation of the cleaning liquid applicator material causes at least a portion (e.g. edge portion) of the cleaning liquid applicator material to contact the porous material layer and/or the further porous material layer(s).

The liquid pick-up area of the porous material layer may be defined by a sealed connection of the porous material layer around the at least one dirt inlet. In such embodiments, the liquid pick-up region may be arranged relative to each of the at least one cleaning liquid outlet such that the liquid pick-up region is bypassed by cleaning liquid delivered towards the surface to be cleaned.

By arranging the liquid pick-up area with respect to the at least one cleaning liquid outlet, thereby allowing the cleaning liquid to bypass the liquid pick-up area, e.g. around the periphery of the liquid pick-up area, the cleaning liquid can be used more efficiently. This is because the cleaning liquid may have a greater chance to reach the surface to be cleaned.

In some embodiments, the cleaning head comprises at least one cleaning liquid distribution portion in which at least one cleaning liquid outlet is provided, each of the at least one cleaning liquid distribution portion being spatially separated from the porous material layer.

In an embodiment provided with the above-mentioned liquid pick-up area, each of the at least one cleaning liquid distribution portion is spatially separated from the liquid pick-up area.

By arranging the cleaning liquid outlet(s) in such separate dispensing part(s), the cleaning liquid can be delivered from the cleaning liquid outlet(s) towards the surface to be cleaned without initially contacting the liquid pick-up area and in some cases the porous material layer. A gap (e.g., an air gap) may be provided between the liquid pick-up area and the cleaning liquid dispensing portion. In some examples, such a gap may be provided between the porous material layer and the cleaning liquid distribution portion(s).

In some embodiments, the cleaning head includes a portion for facing a surface to be cleaned; and a protruding element mounted adjacent to the portion, the protruding element protruding from the cleaning head in the direction of the surface to be cleaned.

In such embodiments, the protruding element may comprise a porous material. Because of the limited contact area between the porous material and the surface to be cleaned, the resistance to movement of the cleaning head over the surface to be cleaned can be reduced.

In some embodiments, the protruding element is arranged to allow the cleaning head to swing over the protruding element to bring the portion into contact with the surface to be cleaned.

A porous material layer of porous material may be included in the protruding elements.

In some embodiments, the liquid pick-up region of the porous material layer is included in the protruding element and terminates between the protruding element and the portion. In this way, the area of the porous material layer to which suction is applied is limited to the protruding elements, thereby helping to reduce the resistance to movement.

Alternatively or additionally, the at least one dirt inlet may be defined in the protruding element. Thus, suction can be applied to a portion of the cleaning head, in other words to the protruding elements, reducing contact of the protruding elements with the surface to be cleaned.

For example, at least one of the dirt inlets is defined by an elastomeric material included in the protruding element, and a porous material is arranged on the elastomeric material. In such examples, the at least one dirty inlet may include or be defined by one or more channels extending through the elastomeric material.

In some embodiments, the cleaning liquid applicator material is deformable to bring at least a portion of the cleaning liquid applicator material into contact with the porous material between the protruding element and the portion.

Thus, excess cleaning liquid squeezed from the cleaning liquid applicator material between the protruding element and the cleaning liquid applicator material, for example by the oscillation of the cleaning head over the protruding element, can be effectively transported via the porous material into the dirty inlet(s).

The protruding element may comprise a curved surface arranged to contact the surface to be cleaned. Such a curved (e.g. rounded) surface of the protruding element may further help to minimize the contact area of the protruding element with the surface to be cleaned and thereby to minimize the resistance to movement of the cleaning head over the surface to be cleaned.

In some embodiments, the protruding element comprises an elastomeric material having a porous material disposed thereon. If, for example, relatively hard protrusions are present on the surface to be cleaned in contact with the porous material, the elastic deformation of such an elastomeric material may reduce the risk of damaging the porous material. Alternatively or additionally, the elastomeric material may assist the porous material to follow any contours of the surface to be cleaned.

In some embodiments, the protruding element may be resiliently mounted adjacent to the portion. For example, the protruding element may be spring mounted to a support member included in the cleaning head. This may help the porous material follow any contours of the surface to be cleaned, thereby facilitating liquid pick-up.

The cleaning head may comprise a further portion for facing the surface to be cleaned, wherein the protruding element is mounted between the portion and the further portion; the cleaning head is thus allowed to swing forward on the protruding element so that the portion contacts the surface to be cleaned, and back so that the other portion contacts the surface to be cleaned.

Thus, the cleaning head can swing over the protruding element to allow this portion (in other words, the front portion) to contact the surface to be cleaned when the cleaning head is pushed forward and/or tilted, and to allow this further portion (in other words, the rear portion) to contact the surface to be cleaned when the cleaning head is pulled backward and/or tilted.

In some embodiments, the cleaning liquid applicator material includes a first applicator portion and a second applicator portion, the first applicator portion being included in the portion and the second applicator portion being included in the other portion.

In such embodiments, the first applicator portion is deformable to bring at least a portion of the first applicator portion into contact with the porous material between the portion and the protruding element, and/or the second applicator portion is deformable to bring at least a portion of the second applicator portion into contact with the porous material between the further portion and the protruding element.

Thus, excess cleaning liquid squeezed from the cleaning liquid applicator material between the protruding element and the first and second cleaning liquid applicator portions may be effectively transported into the dirty inlet(s) via the porous material, for example by swinging the cleaning head forward and backward, respectively.

It should be noted that the porous material differs from the cleaning liquid applicator material (at least) in that the porous material is denser than the cleaning liquid applicator material, for example due to the tighter weave of the porous material comprising the microfiber fabric.

Alternatively or additionally, in some embodiments, the cleaning liquid applicator material may be distinguished from the porous material by the cleaning liquid applicator material comprising a backing layer supporting tufts formed from the fibers; the backing layer supporting the tufts is not included in the porous material.

The cleaning liquid applicator material and/or the porous material may, for example, comprise a plurality of layers of different colors that gradually wear through use of the cleaning head such that the color of the cleaning liquid applicator material and/or the porous material acts as a wear indicator.

Porous materials, including microfiber fabrics for example, may be particularly susceptible to abrasion, and such abrasion may risk compromising the under-pressure retention/liquid pick-up performance of the porous material. Thus, the porous material may comprise a plurality of layers of different colours, for example layers of microfibres of different colours, which progressively wear through the use of the cleaning head, so that the colour of the porous material acts as a wear indicator.

In some embodiments, the cleaning liquid applicator material is capable of being separated from each of the at least one cleaning liquid outlet. This may enable replacement of the cleaning liquid applicator material, for example once the cleaning liquid applicator material has become excessively worn, and/or enable the cleaning liquid applicator material to be cleaned between uses. For example, wear assurance substitutions may be indicated by the colored layer described above that includes cleaning liquid applicator material (when such wear indicating cleaning liquid applicator material is used).

Alternatively or additionally, at least a portion of the porous material can be separated from each of the at least one dirty inlet.

At least a portion of the porous material can be separated from the at least one dirty inlet, can be directly replaced, for example once it is excessively worn, and/or can be cleaned between uses.

In some embodiments, the porous material comprises one or more additional layers of porous material. In addition to the porous material layer sealingly attached to the dirty inlet(s), including one or more additional porous material layers may help to increase the under-pressure that can be maintained in the dirty inlet(s). This in turn helps to operate the above-mentioned under-voltage generator more effectively.

Such further porous material layer(s) may for example be arranged on the outer surface of the porous material layer such that the outer surface of the further porous material layer furthest from the at least one dirt inlet in the thickness direction of the porous material contacts the surface to be cleaned.

In some embodiments, the porous material has a limiting pore diameter of 15 μm or greater as measured using ASTM F316-03, 2019, test a.

It has been found empirically (as further described below) that limiting orifice diameters equal to or greater than 15 μm can help maintain a relatively large under-pressure while ensuring that the orifice is large enough to effectively transport liquid therethrough. Regarding the latter, it is noted that this observation is supported by theory, and that when using the poiseuille equation approximation, the flow resistance can be increased to a power of 4 for smaller holes.

Likewise, the bubble point pressure of the porous material measured using ASTM F316-03, 2019, test a, can be equal to or less than 13500Pa.

In some embodiments, the porous material has an ultimate pore diameter of 105 μm or less as measured using ASTM F316-03, 2019, test a. Limiting the upper limit of the pore diameter helps ensure that the porous material can maintain a sufficient under-pressure.

Likewise, the bubble point pressure of the porous material measured using ASTM F316-03, 2019, test a, can be equal to or greater than 2000Pa.

In some embodiments, the porous material has a limiting pore diameter of equal to or greater than 15 μm and equal to or less than 105 μm as measured using ASTM F316-03, 2019, test a.

In some embodiments, the porous material comprises one or more of a porous fabric, a porous plastic, and a foam.

Such porous plastic may for example take the form of a sintered mesh of plastic particles.

In embodiments where the porous material comprises such a porous plastic, one or more additional layers of porous material, including for example a porous fabric, such as a woven porous fabric, may be disposed on an outer surface of the porous plastic. Such additional porous material layer(s) may be more wettable by water than porous plastics and thus more suitable for contacting a surface to be cleaned when wetted by water.

It is specifically mentioned that porous materials include porous woven fabrics, and most preferably woven microfiber fabrics. Such a woven microfiber fabric may facilitate achieving a desired under-pressure in a wet cleaning apparatus.

Such porous woven fabrics, in particular such woven microfiber fabrics, may be constructed, in particular by the tightness of their weave, to meet the above-mentioned ranges of limiting diameters.

In some embodiments, the porous material has a thickness of less than or equal to 10mm, more preferably less than or equal to 5mm, and most preferably less than or equal to 3mm. Such a maximum thickness may help to minimize the flow resistance through the porous material.

According to another aspect, there is provided a cleaning head for a wet cleaning apparatus, the cleaning head having: at least one cleaning liquid outlet through which cleaning liquid can be delivered; a cleaning liquid applicator material arranged to apply the cleaning liquid to a surface to be cleaned; at least one dirty inlet; and a porous material covering the at least one dirty inlet, the porous material comprising a layer of porous material sealingly attached to the at least one dirty inlet, wherein an edge portion of the porous material abuts an opposing edge portion of the cleaning liquid applicator material.

By the edge portions of the porous material abutting (in other words, bordering and contacting) opposite edge portions of the cleaning liquid applicator material, increased control of the humidity of the cleaning liquid applicator material may be provided.

The opposite edge portions of the cleaning liquid applicator material may, for example, be arranged to contact the surface to be cleaned. Thus, the humidity of the cleaning liquid applicator material can be controlled where the cleaning liquid applicator material contacts the surface to be cleaned, thereby minimizing the risk of excessive wetting of the surface to be cleaned.

According to yet another aspect, there is provided a wet cleaning device comprising a cleaning head according to any of the embodiments described herein; and an under-pressure generator for providing suction to the at least one covered dirt inlet.

Limiting the flow rate to an upper limit may help to minimize the risk that the holes cannot withstand under-pressure and thus "burst", with the result that a large amount of air enters the interior of the wet cleaning device, which in turn may require a larger pump that consumes more power.

In some embodiments, the under-voltage generator is configured to provide less than or equal to 2000cm ³ Flow rate through the porous material per minute.

Such a flow rate may be significantly lower than the flow rate of the conventional wet vacuum cleaner described above. Since the power is equal to the flow rate multiplied by the pressure difference, by dividing the maximum by 2000cm ³ The combination of the/minute flow rate (0.03 l/s) with the maximum 13500Pa differential pressure as the maximum power consumption scheme minimizes the power consumption of the wet cleaning apparatus. This may enable the wet cleaning device to be made relatively compact, for example using smaller batteries, and/or having a relatively long run time.

Alternatively or additionally, the under-voltage generator may be configured to provide a voltage equal to or greater than 15cm ³ Flow rate through the porous material per minute.

This may help to pick up liquid from the surface to be cleaned quickly enough. In some embodiments, 15cm ³ The lower limit of/min may be set to equal or exceed the flow rate of cleaning liquid from the cleaning liquid outlet(s) also included in the cleaning head.

In some embodiments, at 200cm ³ The fluid transport pressure per minute flowing through the porous material is less than 0.25 multiplied by the bubble point pressure as determined by astm f316-03, 2019, test a.

This may mean that the flow resistance through the porous material is kept at a relatively low level.

In some embodiments, the under-voltage generator is configured to generate a voltage by providing 15cm ³ Per minute to 2000cm ³ Per minute, preferably 40cm ³ Per minute to 2000cm ³ Per minute, more preferably 80cm ³ Per minute to 750cm ³ Per minute, most preferably 100cm ³ Per minute to 300cm ³ Flow in the range of/min to provide the suction.

Such flow, i.e. flow rate, may take advantage of the under-pressure retention capability of the porous material and may ensure adequate liquid pick-up while limiting energy consumption.

Alternatively or additionally, the flow provided by the under-pressure generator on the inside of the wet cleaning device between the porous material and the under-pressure generator is set such that the pressure difference between the pressure on said inside of the wet cleaning device and the atmospheric pressure is in the range of 2000Pa to 13500Pa, preferably 2000Pa to 12500Pa, more preferably 5000Pa to 9000Pa, most preferably 7000Pa to 9000 Pa.

The under-pressure generator may be or comprise, for example, a positive displacement pump, such as a peristaltic pump. Such a positive displacement pump may help to maintain an under-pressure in the dirty inlet(s) after the under-pressure generator is deactivated (e.g., shut down) because the pump design inherently limits back flow from the pump outlet. This in turn may alleviate the release of problematic liquids from the porous material, for example after cleaning the surface to be cleaned and/or during loading of the wet cleaning device in the storage area after use.

Alternatively or additionally, the cleaning head may (whether or not an under-pressure generator is present) comprise a valve assembly configured to: allowing a flow for drawing fluid through the porous material into the at least one dirty inlet; and restricting backflow toward the porous material layer.

The valve assembly may help to maintain the under-pressure in the covered dirt inlet(s) by limiting back flow towards the porous material layer by the valve assembly and thereby mitigate the above-mentioned problematic liquid release through the porous material, for example when the under-pressure generator is deactivated.

The wet cleaning device may comprise a dirty liquid collection tank. In such an embodiment, the under-pressure generator may be arranged to draw liquid from the at least one dirty inlet to the dirty liquid tank.

Alternatively or additionally, the wet cleaning device may comprise a cleaning liquid supply for supplying cleaning liquid for delivery via the at least one cleaning liquid outlet towards the surface to be cleaned. Such a cleaning liquid supply may for example comprise a cleaning liquid reservoir and a delivery device, for example a delivery device comprising a pump, for transporting the cleaning liquid to and through the at least one cleaning liquid outlet.

The cleaning liquid supply and the at least one cleaning liquid outlet may be configured to provide continuous delivery of the cleaning liquid towards the surface to be cleaned. Such continuous delivery may be provided, for example, while the under-voltage generator provides suction to the at least one dirty inlet.

The cleaning liquid supply and the under-pressure generator may, for example, be configured such that the flow rate of the cleaning liquid delivered through the at least one cleaning liquid outlet is lower than the flow rate provided by the under-pressure generator to the at least one dirty inlet. This helps to ensure that the surface to be cleaned is not excessively wetted by the cleaning liquid. For example, the flow rate of the cleaning liquid may be 20cm ³ Per minute to 60cm ³ In the range of/min, the flow provided by the under-pressure generator may be 40cm ³ Per minute to 2000cm ³ In the range of/min, more preferably 80cm ³ Per minute to 750cm ³ In the range of/min, most preferably in the range of 100cm ³ Per minute to 300cm ³ In the range of/min.

More generally, the wet cleaning device may be or include, for example, a wet floor cleaning appliance, a window cleaner, a sweeper, or a wet vacuum cleaner, such as a canister, stick, or upright wet vacuum cleaner. In some examples, the wet cleaning apparatus may be or include a robotic wet vacuum cleaner or robotic wet mopping device configured to autonomously move a cleaning head over a surface to be cleaned (e.g., a surface of a floor), for example, in one cleaning direction. Particular mention is made of wet mopping devices.

In a particular non-limiting example, the wet cleaning device is a battery-powered (or battery-powered) wet cleaning device, such as a battery-powered (or battery-powered) wet mopping apparatus, wherein the under-voltage generator (e.g., pump) is powered (or is capable of being powered) by a battery electrically connected (or connectable) thereto. This example is particularly mentioned because of the power consumption reducing effect that may be provided by the porous material covering the dirty inlet(s) to which suction of the under-pressure generator is provided.

The embodiments described herein with respect to the cleaning head are applicable to a wet cleaning device and the embodiments described herein with respect to a wet cleaning device are applicable to a cleaning head.

Drawings

Examples of the present invention will now be described in detail with reference to the accompanying drawings, in which:

figure 1 schematically illustrates an underside of a cleaning head according to one example;

FIG. 2 provides a schematic cross-sectional view of a cleaning liquid distribution strip included in the cleaning head shown in FIG. 1;

figure 3 schematically illustrates an underside of a cleaning head according to a second example, wherein cleaning liquid applicator material is separated from the cleaning head;

figure 4 schematically illustrates the underside of the cleaning head shown in figure 3 with a cleaning liquid applicator fabric attached;

FIG. 5A schematically illustrates a porous material layer and a dirty inlet of an exemplary cleaning head;

FIG. 5B provides a schematic cross-sectional view of the porous material layer and the dirt inlet shown in FIG. 5A;

FIG. 6A schematically depicts an example of sealed attachment of a porous material layer around a dirty inlet;

FIG. 6B provides a schematic cross-sectional view of the exemplary seal attachment shown in FIG. 6A;

fig. 7A schematically illustrates a variation of the seal attachment illustrated in fig. 6A and 6B;

FIG. 7B provides a schematic cross-sectional view of the exemplary seal attachment shown in FIG. 7A;

FIG. 8 provides a schematic cross-sectional view of a variation of the seal attachment shown in FIGS. 7A and 7B;

FIG. 9 provides a schematic cross-sectional view of a variation of the seal attachment shown in FIG. 8;

FIG. 10 provides a schematic illustration of fluid transport through three exemplary porous materials;

FIG. 11 schematically illustrates a test arrangement for testing the behavior of a porous material when liquid and suction are applied thereto;

FIG. 12 provides a plot of under-voltage versus time for data obtained from using the test arrangement shown in FIG. 11;

FIG. 13 provides several pressure-time graphs of porous materials including different numbers of porous material layers;

Fig. 14 schematically shows a liquid-transporting state, an intermediate state, and an end state sequence of the porous material when suction is applied to the porous material;

FIG. 15 provides several pressure versus time plots of porous materials of different pore sizes;

figure 16 schematically illustrates an exemplary cleaning head moving over a surface to be cleaned;

fig. 17-23 provide schematic cross-sectional views of a porous material mounted to a support member;

figures 24-30 schematically illustrate various exemplary cleaning heads;

FIG. 31 schematically illustrates an exemplary cleaning head that may be swung over a protruding element to bring a portion of the underside of the cleaning head into contact with a surface to be cleaned;

FIG. 32A schematically depicts an example of sealed attachment of a porous material layer around a dirty inlet;

FIG. 32B provides a schematic cross-sectional view of the exemplary seal attachment shown in FIG. 32A;

figure 33A provides a view of an end of a cleaning head according to one example;

FIG. 33B provides a view of the top side of the cleaning head shown in FIG. 33A;

FIG. 33C provides a schematic cross-sectional view of a protruding element/separable member according to one example;

FIG. 33D provides a schematic cross-sectional view of a protruding element/separable member according to another example;

FIG. 33E provides a schematic cross-sectional view of an exemplary detachable element including additional porous material layer(s) and cleaning liquid applicator material;

figure 33F provides a perspective view of a cleaning head comprising the protruding element/separable member shown in figure 33C or 33D and the separable element shown in figure 33E;

fig. 34 schematically illustrates an exemplary wet cleaning device before (left side panels), during (center panels) and after (right side panels) drawing liquid through the porous material;

FIG. 35 schematically illustrates an example wet cleaning device having an under-voltage generator that is activated (left-hand square) and deactivated (right-hand square);

FIG. 36 schematically illustrates an under-pressure generator in the form of a peristaltic pump;

FIG. 37A schematically illustrates pores of a porous material layer of an exemplary wet cleaning device;

FIG. 37B schematically illustrates foam accumulation in the wet cleaning device illustrated in FIG. 37A;

FIG. 37C graphically illustrates an operating window of the wet cleaning device, particularly when the wet cleaning device is activated;

FIG. 38 schematically illustrates an example wet cleaning apparatus that includes an under-voltage generator apparatus having an under-voltage generator, a pressure sensor, and a controller;

FIG. 39 schematically illustrates an example wet cleaning device having an under-voltage generator device with an under-voltage generator and a mechanical regulator;

FIG. 40 schematically illustrates an example wet cleaning apparatus, an under-pressure generator of which includes a pressure-limiting liquid pump;

FIG. 41 schematically illustrates an example wet cleaning device with an under-pressure generator including a pressure-limited air pump;

fig. 42 schematically illustrates an exemplary wet cleaning device in the form of a wet vacuum cleaner; and

fig. 43 schematically illustrates an exemplary wet cleaning device in the form of a robotic wet vacuum cleaner.

Detailed Description

The present invention will be described with reference to the accompanying drawings.

It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, system, and method, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, system, and method of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the drawings are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to designate the same or similar components.

A cleaning head for a wet cleaning device is provided. The cleaning head has at least one cleaning liquid outlet through which cleaning liquid can be delivered. The cleaning liquid applicator material is, for example, adjacent to the at least one cleaning liquid outlet. The cleaning liquid applicator material is arranged to apply a cleaning liquid to a surface to be cleaned. The cleaning head also has at least one dirty inlet and a porous material covering the at least one dirty inlet. The porous material comprises a layer of porous material sealingly attached to at least one dirty inlet. In one aspect, the cleaning liquid applicator material is deformable to bring at least a portion of the cleaning liquid applicator material into contact with the porous material. In another aspect, the edge portion of the porous material abuts an opposing edge portion of the cleaning liquid applicator material. These aspects provide an alternative solution to the same problem of controlling the humidity of the cleaning liquid applicator material. A wet cleaning apparatus including a cleaning head is also provided.

Figure 1 shows a cleaning head 100 according to a non-limiting example. In particular, the underside 102 of the cleaning head 100 is shown in FIG. 1. The underside 102 faces a surface (not visible in fig. 1) to be cleaned using the cleaning head 100.

As is apparent from the view shown in fig. 1, the cleaning head 100 includes at least one cleaning liquid outlet 104 therein. The cleaning liquid may be delivered through, for example, each of the at least one cleaning liquid outlet 104. It should be noted that the at least one cleaning liquid outlet need not be provided on the underside 102 of the cleaning head 100, and alternatively may be provided elsewhere in the cleaning head 100, as long as cleaning liquid can be delivered via the cleaning liquid outlet(s) to reach the surface to be cleaned.

The cleaning liquid may comprise or consist of water. Thus, the cleaning liquid may be an aqueous cleaning liquid. In some non-limiting examples, which will be discussed in more detail below, the cleaning liquid is an aqueous detergent solution.

In the non-limiting example shown in fig. 1, the cleaning liquid outlets 104 are arranged in a row along the length 106 of the cleaning head 100. This may help the cleaning head 100 wet the surface to be cleaned with cleaning liquid along the length 106 of the cleaning head 100. It should be noted, however, that any suitable configuration or pattern of cleaning liquid outlets 104 is contemplated as long as other components are provided that are capable of receiving the cleaning head 100.

In the particular example shown in fig. 1, sixteen cleaning liquid outlets 104 are included in the cleaning head 100, it being noted that more cleaning liquid outlets 104 may help to increase the wetting uniformity of the surface to be cleaned. However, any suitable number of cleaning liquid outlets 104 may be provided in the cleaning head 100, such as one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty or more.

In some embodiments, as shown in FIG. 1, the cleaning head 100 includes a cleaning liquid distribution strip 108. As shown, at least some or in this example all of the cleaning liquid outlets 104 may be included in the cleaning liquid distribution strip 108.

Fig. 2 provides a cross-sectional view of the cleaning liquid distribution strip 108 included in the exemplary cleaning head 100 shown in fig. 1. In this non-limiting example, the cleaning liquid distribution strip 108 includes a channel 110 that may be supplied with cleaning liquid, for example, from a suitable cleaning liquid reservoir (not visible in fig. 2) via an inlet 112.

In the example shown in fig. 2, the inlet 112 is provided at the end of the cleaning liquid distribution strip 108 or near the end of the cleaning liquid distribution strip 108, however, it is also conceivable that the inlet 112 is provided at a central position along the length of the cleaning liquid distribution strip 108. Alternatively or additionally, the cleaning liquid distribution strip 108 includes a plurality of inlets 112, such as a pair of inlets 112 disposed at opposite ends of the cleaning liquid distribution strip 108.

The cleaning liquid may exit the cleaning liquid distribution strip 108 through an aperture in the cleaning liquid distribution strip 108 defining the cleaning liquid outlet 104. Such apertures may be sized such that when the channel 110 is being filled, the passage of cleaning liquid, such as aqueous cleaning liquid, through the apertures is restricted due to the surface tension of the cleaning liquid, but once the channel 110 has been filled, while allowing the cleaning liquid to pass through all of the apertures of the cleaning liquid distribution strip 108. This may allow for relatively uniform wetting of the surface to be cleaned across the length 106 of the cleaning head 100.

To this end, each cleaning liquid outlet 104 may have a diameter of, for example, less than 1mm, for example, in the range of 0.1mm to 1mm, preferably 0.1mm to 0.8mm, most preferably 0.1mm to 0.5mm, for example, about 0.3mm.

The cleaning liquid distribution strip 108 may be formed of any suitable material, such as a metal, metal alloy (e.g., stainless steel), and/or polymer. Forming the cleaning liquid distribution strip 108 from a polymer can make the cleaning liquid distribution strip 108 lighter and/or less expensive to manufacture.

Returning to fig. 1, the cleaning head 100 also includes a porous material that includes a layer of porous material 114, or in some embodiments, is comprised of a layer of porous material 114. Although not visible in fig. 1, the cleaning head 100 has at least one dirty inlet. Each of the dirty inlet(s) is covered by a layer of porous material 114.

The porous material layer 114 may be arranged between the dirty inlet(s) and the surface to be cleaned such that dirty liquid on the surface to be cleaned is first transported into the pores of the porous material layer 114 and then from the porous material layer 114 into the dirty inlet(s).

The view provided in fig. 1 shows an outer surface 116 of the porous material layer 114, which outer surface 116 faces the surface to be cleaned.

A layer 114 of porous material is disposed at or near the underside 102 of the cleaning head 100. More generally, the porous material, although not necessarily particularly the porous material layer 114 included in the porous material, may contact the surface to be cleaned and/or the liquid on the surface to be cleaned.

In a non-limiting example in which the porous material comprises one or more further porous material layers (not visible in fig. 1) arranged on the outer surface 116 of the porous material layer 114, the outer surface of the further porous material layer furthest from the at least one soil inlet in the thickness direction of the porous material may contact the surface to be cleaned.

The porous material layer 114 covering each of the at least one dirty inlet may help to maintain an under-pressure in the dirty inlet(s) with or without a constant flow applied to the dirty inlet(s), for example, by an under-pressure generator (e.g., a pump) fluidly connected to the dirty inlet.

The porous material layer 114 may, for example, comprise or consist of a porous fabric and/or a porous foam. The porous fabric may be, for example, a microfiber fabric.

Similarly, each of the one or more additional porous material layers described above may include or consist of a porous fabric (e.g., a microfiber fabric) and/or a porous foam.

The term "microfiber fabric" as used herein refers to a fabric formed from synthetic fibers formed from filaments having a denier of less than 1 dtex.

Such microfiber fabrics may include, for example, polyester fibers, polyamide fibers, and combinations of polyester and polyamide fibers.

The microfiber fabric may be, for example, microfiber suede (chamois).

In other examples, the porous fabric is a natural suede, such as made from suede, deer, goat or sheep skin.

The surface tension of the liquid retained in the pores of the porous material layer 114 may help to maintain the under-pressure. This surface tension may be overcome at a point (or points) on the outer surface 116 of the porous material layer 114 that is in contact with the liquid, thereby causing the liquid to be transported through the porous material layer 114 in the direction of the fouling inlet(s).

Porous materials, including microfiber fabrics for example, may be particularly susceptible to abrasion, and such abrasion may risk compromising the under-pressure retention/liquid pick-up performance of the porous material. Thus, the porous material may comprise a plurality of layers of different colors that gradually wear through use of the cleaning head 100, such that the color of the porous material acts as a wear indicator.

In some embodiments, such as the embodiment shown in fig. 1, the porous material and/or the porous material layer 114 included in the porous material is elongated so as to have a maximum dimension that extends parallel to the length 106 of the cleaning head 100.

In the non-limiting example shown in fig. 1, the porous material layer 114 is located at different positions along the width 118 of the cleaning head 100 relative to the cleaning liquid outlet 104.

In some embodiments, such as shown in fig. 1, the cleaning head 100 includes a portion 120 for facing the surface to be cleaned. The one or more cleaning liquid outlets 104 may be arranged to deliver cleaning liquid to the portion 120 of the cleaning head 100.

Although not visible in the view provided in fig. 1, protruding elements may be mounted adjacent to portion 120, wherein the protruding elements protrude from the cleaning head 100 in the direction of the surface to be cleaned. The protruding elements may be considered elements that are individually mounted in the cleaning head 100 relative to the portion 120.

Due to the protruding nature of the protruding elements, the protruding elements may have limited contact with the surface to be cleaned. The protruding element may, for example, have a smaller contact area with the surface to be cleaned than the portion 120.

In at least some embodiments, the protruding element comprises a porous material. Because of the limited contact area between the porous material and the surface to be cleaned, the resistance to movement of the cleaning head 100 over the surface to be cleaned can be reduced. This will be described in further detail below with reference to fig. 31.

In some embodiments, the cleaning head 100 may oscillate on the protruding element in a first direction to bring the portion 120 into contact with the surface to be cleaned and oscillate on the protruding element in a second direction opposite the first direction to separate the portion 120 from the surface to be cleaned.

In such embodiments, the protruding element may be considered a rocker that allows the cleaning head 100 to swing onto the portion 120. In order to achieve this swinging function, the contact of the protruding element with the surface to be cleaned is limited.

In some embodiments, such as in the non-limiting example shown in fig. 3, the cleaning head 100 includes a portion 120 for facing the surface to be cleaned and a further portion 122. In such embodiments, the porous material layer 114 may be disposed between the portion 120 and the further portion 122.

Although not visible in the view provided in fig. 3, when the cleaning head 100 includes the protruding elements described above, the protruding elements may be mounted between the portion 120 and the further portion 122. Thus, the protruding element may be an element that is mounted separately with respect to both the portion 120 and the further portion 122. In this way, the cleaning head 100 can be swung forward on the protruding element to bring the portion 120 into contact with the surface to be cleaned and back to bring the further portion 122 into contact with the surface to be cleaned.

Regardless of whether the cleaning head 100 includes protruding elements, the cleaning liquid outlet(s) 104 may be arranged to deliver cleaning liquid to the portion 120 and the further portion 122 of the cleaning head 100.

In the non-limiting example shown in fig. 3, the cleaning head 100 includes a cleaning liquid distribution strip 108 and a further cleaning liquid distribution strip 124, the aperture of the cleaning liquid distribution strip 108 defining the cleaning liquid outlet 104, the cleaning liquid outlet 104 delivering cleaning liquid to the portion 120, the further aperture of the further cleaning liquid distribution strip 124 defining the cleaning liquid outlet 104, the cleaning liquid outlet 104 delivering cleaning liquid to the further portion 122, as described above with respect to fig. 1 and 2.

Both the cleaning liquid distribution strip 108 and the additional cleaning liquid distribution strip 124 may extend parallel to the length 106 of the cleaning head 100, as shown in fig. 3.

In some embodiments, such as the embodiment shown in fig. 4, the cleaning head 100 includes a cleaning liquid applicator material 126, 128 adjacent each of the at least one cleaning liquid outlet 104, the cleaning liquid applicator material 126, 128 being arranged to apply cleaning liquid to a surface to be cleaned. In other words, the cleaning liquid applicator materials 126, 128 may receive the cleaning liquid delivered from the cleaning liquid outlet(s) 104 and deliver the cleaning liquid to the surface to be cleaned.

The cleaning liquid applicator materials 126, 128 may, for example, comprise polyamide and/or polyester fibers.

Alternatively or additionally, the cleaning liquid applicator materials 126, 128 include a combination of thinner fibers and thicker fibers.

The thinner fibers may be, for example, less than or equal to 1 dtex, and the thicker fibers may have a thickness greater than 0.01mm, for example, the thicker fibers may have a thickness of about 0.05mm.

Thicker fibers, which may be made of polyamide or polyester, may help reduce friction between the cleaning liquid applicator materials 126, 128 and the surface to be cleaned, while thinner fibers, such as made of polyamide or polyester, may help enhance soil retention.

Thicker fibers may also provide elasticity to the cleaning liquid applicator materials 126, 128, thereby minimizing compression of the cleaning liquid applicator materials 126, 128.

The compression reducing capability of thicker fibers is particularly useful in embodiments where the cleaning liquid applicator materials 126, 128 are included in the portion 120 and/or the further portion 122 adjacent the protruding element rocker. This is because the minimized compression may help ensure that a consistent degree of oscillation on the protruding elements results in the cleaning liquid applicator materials 126, 128 contacting the surface to be cleaned during continued use of the cleaning head 100.

The thickness of the cleaning liquid applicator materials 126, 128 may alternatively or additionally be selected or limited, for example, in view of the extent of protrusion of the protruding elements relative to the portion 120 and/or the further portion 122, so as to minimize compression of the cleaning liquid applicator materials 126, 128 during use of the cleaning head 100.

In embodiments where the cleaning liquid applicator material 126, 128 includes a combination of thinner fibers and thicker fibers, the fibers may be arranged relative to one another in any suitable manner. For example, the cleaning liquid applicator material 126, 128 may include thicker fibrous bands adjacent to thinner fibrous bands. The strips may each extend along the length 106 of the cleaning head 100 such that the fiber thickness alternates in the width 118 direction. This configuration may help reduce friction as the cleaning head 100 moves in a direction parallel to the width 118 direction.

In embodiments where the cleaning liquid applicator materials 126, 128 include both polyamide and polyester fibers, the fibers may be arranged relative to one another in any suitable manner. For example, the cleaning liquid applicator material 126, 128 may include a polyamide fiber band adjacent to a polyester fiber band. The strips may each extend along the length 106 of the cleaning head 100 such that the fiber types alternate in the width 118 direction.

The cleaning liquid applicator materials 126, 128 may, for example, include a backing layer that supports a material (e.g., a polyamide and/or polyester fiber containing material) in contact with the surface to be cleaned. The backing layer may be formed of any suitable backing fabric material, such as polyester.

Such backing layers may be provided with tufts, for example formed from polyamide and/or polyester fibers. Such tufts may help the cleaning liquid applicator material 126, 128 follow the contours of the surface to be cleaned and/or may help the cleaning liquid applicator material 126, 128 retain dirt particles while also minimizing the risk of scraping the surface to be cleaned.

In some embodiments, the cleaning liquid applicator materials 126, 128 may be distinguished from the porous material by (at least) a backing layer (e.g., the backing layer supporting tufts described above) included in the cleaning liquid applicator materials 126, 128 but not included in the porous material.

In some non-limiting examples, the fibers comprising the cleaning liquid applicator materials 126, 128 are the same as the fibers comprising the porous material.

In an alternative example, one of the ways in which the cleaning liquid applicator materials 126, 128 can be distinguished from the porous material is the fineness, e.g., denier, of the threads and/or fibers of the respective material (e.g., threads and/or fibers of the respective material that are in contact with the surface to be cleaned). For example, the fibers comprising the porous material layer(s) of the porous material may be finer than the fibers of the cleaning liquid applicator materials 126, 128. Alternatively or additionally, the lines of porous material layer(s) comprising the porous material may be thinner than the lines of cleaning liquid applicator material 126, 128.

The porous material may generally be denser than the cleaning liquid applicator materials 126, 128, for example due to the tighter weave of the microfiber fabric.

In some embodiments, the cleaning liquid applicator material 126, 128 includes multiple layers of different colors that gradually wear through use of the cleaning head 100 such that the color of the cleaning liquid applicator material 126, 128 acts as a wear indicator.

In some embodiments, the cleaning liquid applicator material 126, 128 may be separated from each of the at least one cleaning liquid outlet 104. This may enable replacement of the cleaning liquid applicator materials 126, 128, for example, once the cleaning liquid applicator materials 126, 128 have worn excessively, and/or enable the cleaning liquid applicator materials 126, 128 to be cleaned between uses. For example, wear may be indicated by the colored layers described above including the cleaning liquid applicator materials 126, 128.

The cleaning liquid applicator materials 126, 128 may be attached to the cleaning head 100 in any suitable manner, particularly to the underside 102 of the cleaning head 100 in the non-limiting example shown in fig. 1-4.

Returning to fig. 3, the depicted cleaning head 100 includes at least one fastening member 130A, 130B, 132A, 132B, in this example in the form of a Velcro strip (Velcro strip), which engages with additional fastening member(s) (not visible) on the cleaning liquid applicator material 126, 128. The further fastening member(s) may for example be included in the above-mentioned backing layer of cleaning liquid applicator material 126, 128 or attached to the above-mentioned backing layer of cleaning liquid applicator material 126, 128.

Alternative ways of attaching (e.g., detachably coupling) the cleaning liquid applicator materials 126, 128 to the cleaning head 100, in particular to the at least one cleaning liquid outlet 104, are contemplated, such as using ejectors, button-button hole arrangements, zippers, and the like.

In some embodiments, as shown in fig. 4, the cleaning liquid applicator material 126, 128 includes a first applicator portion 126 and a second applicator portion 128, with the porous material layer 114 disposed between the first applicator portion 126 and the second applicator portion 128.

When the first applicator portion 126 is included in the cleaning head 100, the first applicator portion 126 may be included in the portion 120 of the cleaning head 100 described above.

In embodiments in which a cleaning liquid applicator material (e.g., first applicator portion 126) is included in portion 120, the portion may be adapted to contact and facilitate cleaning of the surface to be cleaned, such as by facilitating application of a cleaning liquid to the surface to be cleaned.

However, it is also conceivable to not include cleaning liquid applicator material in the portion 120, for example if the cleaning head 100 is supplied without such cleaning liquid applicator material. In this case, although the portion 120 has a potentially smaller cleaning capacity than if the cleaning liquid applicator material (e.g., the first applicator portion 126) were included in the portion 120, the portion 120 may still be adapted to contact the surface to be cleaned (where the portion 120 is not required to include the cleaning liquid applicator material, the portion 120 may be in contact with the surface to be cleaned).

The first applicator portion 126 may include additional fastening member(s) as described above that engage with fastening member(s) 130A, 130B provided on the cleaning head 100 for incorporation of the first applicator portion 126 in the portion 120.

Similarly, when the second applicator portion 128 is included in the cleaning head 100, the second applicator portion 128 may be included in the aforementioned additional portion 122 of the cleaning head 100.

In such embodiments, the second applicator portion 128 may include additional fastening member(s) as described above that engage with the fastening member(s) 132A, 132B provided on the cleaning head 100 for incorporation of the second applicator portion 128 in the additional portion 122.

In some embodiments, the at least one cleaning liquid outlet 104 comprises at least one pair of cleaning liquid outlets 104, with a layer of porous material 114 disposed between each pair of cleaning liquid outlets 104.

In embodiments where the cleaning liquid applicator material 126, 128 includes a first applicator portion 126 and a second applicator portion 128, the first applicator portion 126 may be adjacent one of the pair of cleaning liquid outlets 104 and the second applicator portion 128 adjacent the other of the pair of cleaning liquid outlets 104. Such an example is shown in fig. 3 and 4.

In at least some embodiments, the porous material (although not necessarily particularly the porous material layer 114 included in the porous material) contacts the cleaning liquid applicator fabrics 126, 128.

By the porous material contacting the cleaning liquid applicator material 126, 128, some cleaning liquid may be transferred from the cleaning liquid applicator material 126, 128 to the porous material and into the dirty inlet(s). Such a configuration may help prevent excess cleaning liquid from accumulating in the cleaning liquid applicator materials 126, 128, and thus may help minimize excessive wetting of the surface to be cleaned, for example, by dripping cleaning liquid from the cleaning liquid applicator materials onto the surface to be cleaned. Alternatively or additionally, by contacting the cleaning liquid applicator materials 126, 128 with the porous material, the cleaning liquid in the latter can be used to effectively rinse the porous material covering the dirty inlet(s).

In a non-limiting example, the porous material layer 114 contacts the cleaning liquid applicator materials 126, 128. In examples where the porous material includes one or more additional porous material layers (not visible in fig. 3 and 4) disposed on the outer surface 116 of the porous material layer 114, the porous material layer 114 and/or the additional porous material layer(s) may contact the cleaning liquid applicator materials 126, 128.

Although the porous material contacts the cleaning liquid applicator materials 126, 128, these materials may also be arranged to contact the surface to be cleaned. This may be accomplished in any suitable manner. In some embodiments, as shown in fig. 3 and 4, the edge portion 134 of the porous material abuts an opposing edge portion 136 of the cleaning liquid applicator material 126, 128. Thus, cleaning liquid may be first delivered into the cleaning liquid applicator materials 126, 128 and only subsequently delivered from the cleaning liquid applicator materials 126, 128 into the porous material via the adjoining edge portions 134, 136 of the respective materials. This may provide enhanced control over the humidity of the cleaning liquid applicator materials 126, 128.

Alternatively or additionally, the cleaning liquid applicator material 126, 128 may be deformable to bring at least a portion of the cleaning liquid applicator material 126, 128 into contact with the porous material.

By enabling the cleaning liquid applicator materials 126, 128 to deform such that at least a portion of the cleaning liquid applicator materials 126, 128 are in contact with the porous material, some cleaning liquid may be transferred from the cleaning liquid applicator materials 126, 128 to the porous material in a particularly controlled manner. In this way, excessive wetting of the surface to be cleaned may be minimized, for example, by dripping cleaning liquid from the cleaning liquid applicator materials 126, 128 onto the surface to be cleaned. Alternatively or additionally, by deforming the cleaning liquid applicator material 126, 128 such that at least a portion of the cleaning liquid applicator material 126, 128 contacts the porous material, the cleaning liquid in the latter may be used to effectively flush the porous material.

In at least some embodiments, the cleaning liquid applicator materials 126, 128 are configured to deform upon contact with a surface to be cleaned and/or upon wetting by a liquid (e.g., water).

Such wetting may be the result of the delivery of cleaning liquid from the cleaning liquid outlet(s) to the cleaning liquid applicator materials 126, 128 and/or as a result of the presence of liquid on the surface to be cleaned.

In a non-limiting example, the cleaning liquid applicator materials 126, 128 include tufts formed from fibers and a backing layer supporting the tufts. Such tufts can deform to contact the porous material, for example, upon contact with a surface to be cleaned and/or upon wetting by a liquid such as water.

While the tufts remain in contact with the porous material, cleaning liquid can be transferred from the cleaning liquid applicator materials 126, 128 to the porous material via the tufts.

In some embodiments, the cleaning liquid applicator material may be deformed such that the edge portions 136 of the cleaning liquid applicator materials 126, 128 are in contact with the porous material, such as in contact with the edge portions 134 of the porous material.

For example, when the cleaning liquid applicator materials 126, 128 are deformed such that the edge portions 136 of the cleaning liquid applicator materials 126, 128 are in contact with the porous material, the edge portions 136 of the cleaning liquid applicator materials 126, 128 may abut the (opposing) edge portions 134 of the porous material.

In some embodiments, the edge portion 136 of the cleaning liquid applicator material 126, 128 is arranged to contact the surface to be cleaned at least when the cleaning liquid applicator material 126, 128 is deformed to bring the edge portion 136 of the cleaning liquid applicator material 126, 128 into contact with the porous material. Thus, the humidity of the cleaning liquid applicator materials 126, 128 can be controlled where the cleaning liquid applicator materials 126, 128 contact the surface to be cleaned, thereby minimizing the risk of excessive wetting of the surface to be cleaned.

In a non-limiting example, the cleaning liquid applicator materials 126, 128 can be deformed such that at least a portion of the cleaning liquid applicator materials 126, 128 are in contact with the porous material layer 114 of porous material. In examples where the porous material includes one or more additional porous material layers, deformation of the cleaning liquid applicator material 126, 128 causes at least a portion (e.g., edge portion 136) of the cleaning liquid applicator material 126, 128 to contact the porous material layer 114 and/or the additional porous material layer(s).

In embodiments where the cleaning head 100 includes the protruding elements described above, the abutting opposing edge portions 134, 136 of the porous and cleaning liquid applicator materials 126, 128 are preferably positioned between the protruding elements and the portion 120. In this way, excess cleaning liquid squeezed from the cleaning liquid applicator material 126, 128 between the protruding element and the cleaning liquid applicator material 126, 128, for example, by swinging the cleaning head 100 via the protruding element, may be effectively transported into the dirty inlet(s) via the porous material.

It should be noted that contact between the porous material and the cleaning liquid applicator materials 126, 128 may be provided on the surface contact side of the material to be cleaned. This may help to avoid cleaning liquid from directly entering the porous material without unduly wetting the cleaning liquid applicator materials 126, 128 or rinsing the porous material.

In some embodiments, the cleaning liquid applicator materials 126, 128 may be deformed such that at least a portion of the cleaning liquid applicator materials 126, 128 are in contact with the porous material between the protruding elements and the portion 120.

Thus, excess cleaning liquid squeezed from the cleaning liquid applicator materials 126, 128, between the protruding elements and the cleaning liquid applicator materials, for example, caused by oscillation of the cleaning head 100 over the protruding elements, may be effectively transported into the dirty inlet(s) via the porous material.

In embodiments where the cleaning liquid applicator material 126, 128 includes the first applicator portion 126 and the second applicator portion 128 described above, the opposing edge portions 136 of the cleaning liquid applicator material 126, 128 may be included in the first applicator portion 126, as shown in fig. 4. Further, a further edge portion 138 of porous material may abut a further opposite edge portion 140 of the second applicator portion 128. Such an example is depicted in fig. 3 and 4.

When the protruding element is disposed between the portion 120 and the further portion 122, the abutting opposing edge portions 134, 136 of the porous material and the first applicator portion 126 are preferably positioned between the protruding element and the portion 120, and the abutting opposing further edge portions 138, 140 of the porous material and the second applicator portion 128 are preferably positioned between the protruding element and the further portion 122.

In this manner, excess cleaning liquid squeezed from the cleaning liquid applicator material 126, 128, between the protruding elements and the first and second cleaning liquid applicator portions 126, 128, for example, caused by swinging the cleaning head 100 forward and backward, respectively, may be effectively transported into the dirty inlet(s) via the porous material.

The opposing edge portions 136 and/or the further opposing edge portions 140 (when present) of the cleaning liquid applicator materials 126, 128 may, for example, be arranged to contact the surface to be cleaned. Thus, the humidity of the cleaning liquid applicator materials 126, 128 can be controlled where the cleaning liquid applicator materials 126, 128 contact the surface to be cleaned, thereby minimizing the risk of excessive wetting of the surface to be cleaned.

In some embodiments, the first applicator portion 126 may be deformed to bring at least a portion of the first applicator portion 126 into contact with the porous material between the portion 120 and the protruding element, and/or the second applicator portion 128 may be deformed to bring at least a portion of the second applicator portion 128 into contact with the porous material between the further portion 122 and the protruding element.

Fig. 5A provides a plan view illustrating the porous material layer 114 and at least one of the dirty inlets 142A, 142B of the exemplary cleaning head 100. Fig. 5B provides a schematic cross-sectional view of the porous material layer 114 and at least one of the dirty inlets 142A, 142B shown in fig. 5A.

In some embodiments, as shown in fig. 5A and 5B, each of the at least one dirty inlet 142A, 142B is defined by an opening of one or more tubes 144A, 144B that are fluidly connected or connectable to an under-pressure generator (not visible in fig. 5A and 5B).

In the non-limiting example shown in fig. 5A and 5B, the cleaning head 100 includes a pair of dirty inlets 142A, 142B, but any suitable number of dirty inlets 142A, 142B is contemplated, such as one, two, three, four, five, six, or more.

When multiple dirt inlets 142A, 142B are included in the cleaning head 100, they may, for example, be of the same size as one another.

Alternatively or additionally, when multiple (e.g., a pair) dirt inlets 142A, 142B are employed, the dirt inlets 142A, 142B may be spaced apart along the length 106 of the cleaning head 100 to provide relatively uniform suction along the length 106 of the cleaning head 100. For example, the distance along length 106 between the center of cleaner head 100 and the center of dirt inlet 142A may be the same or substantially the same as the distance along length 106 between the center of dirt inlet 142B and the center.

If a single dirty inlet is employed, this may be provided at a central location of the cleaning head 100 to provide a relatively symmetrical suction profile along the length 106 of the cleaning head 100.

More generally, the liquid pickup region PR of the porous material layer 114 is defined by the sealed attachment of the porous material layer 114 around, for example, each of the at least one dirty inlet 142A, 142B.

Such a sealed attachment may help to maintain an under-pressure in the covered dirty inlets 142A, 142B, as the under-pressure is minimized or prevented by leakage losses between the dirty inlets 142A, 142B and the porous material layer 114.

The sealed attachment may be achieved in any suitable manner, such as by gluing or welding the porous material layer 114 around each of the at least one dirty inlet 142A, 142B, such as gluing and/or welding the porous material layer 114 around the opening(s) defining the dirty inlet(s) 142A, 142B to the tube(s) 144A, 144B described above.

Mention is made in particular of sealingly attaching the porous material layer 114 to the dirty inlet(s) 142A, 142B by heat sealing (e.g. ultrasonic welding). It has been found that this provides a particularly airtight seal in a straightforward manner, which helps to maintain the under-pressure in the dirty inlet(s) 142A, 142B.

Referring to fig. 5B, 6A and 6B, a non-limiting example of the sealed attachment of the porous material layer 114 to the dirty inlet 142A, 142B is achieved by the cleaning head 100, the cleaning head 100 comprising an impermeable portion 146 sealed to the porous material layer 114 (e.g., to an inner surface 148 of the porous material layer 114) and surrounding the dirty inlet 142A, 142B, whereby the dirty inlet 142A, 142B is exposed to a sealed cavity 150 between the porous material layer 114 and the impermeable portion 146.

The impermeable portion 146 may, for example, comprise or consist of a polymeric film, such as a thermoplastic film. Various alternative sealing arrangements are described below, some of which do not include such a polymeric film.

In the non-limiting example shown in fig. 6A and 6B, a seal 152, formed, for example, via adhesion and/or welding of the impermeable portion 146 (e.g., a polymeric film), extends around the perimeter of the porous material layer 114 and around the dirty inlet 142A, 142B.

In at least some embodiments, such as the embodiments shown in fig. 7A and 7B, the liquid pick-up region PR is arranged relative to the at least one cleaning liquid outlet 104 to allow cleaning liquid to bypass, e.g. pass around, the periphery of the liquid pick-up region PR to reach or at least be directed towards the surface to be cleaned.

This may allow a more efficient use of the cleaning liquid. This is because the cleaning liquid has a greater chance to reach the surface to be cleaned, such as by the cleaning liquid applicator materials 126, 128 described above (when included in the cleaning head 100).

In other examples, the porous material may be attached around the dirty inlet(s) 142A, 142B, for example against the cleaning head 100 or a component of the cleaning head 100, at least in part by the flow provided by the under-pressure generator being adsorbed against the dirty inlet(s) 142A, 142B.

In some embodiments, the cleaning head 100 comprises a liquid delivery support structure 154 in the cavity 150, the liquid delivery support structure 154 being arranged to provide one or more flow paths between the porous material layer 114, in particular the pores of the porous material layer 114, and the at least one dirt inlet 142A, 142B in the liquid pick-up region PR.

The porous material layer 114 (e.g., microfiber fabric) and/or the impermeable portion 146 (e.g., polymer film) may be flexible such that an under-pressure may cause the porous material layer 114 and the impermeable portion 146 to be stretched toward each other. This may present a risk of restricting the flow of liquid from the porous material layer 114 to the at least one fouling inlet 142A, 142B. Although the porous material layer 114 and the impermeable portion 146 are drawn toward each other, the liquid delivery support structure 154 may help ensure that liquid may still be delivered from the porous material layer 114, and in particular the pores of the porous material layer 114, to the at least one dirty inlet 142A, 142B.

The liquid delivery support structure 154 may be implemented in any suitable manner. In the non-limiting example shown in fig. 7A and 7B, the liquid transport support structure 154 includes or is defined by one or more mesh layers. In such examples, the one or more flow paths described above may be provided by spaces between elements that make up the mesh layer(s). Alternative examples of the liquid delivery support structure 154 will be described below.

As described above, in some embodiments, the porous material may include one or more additional porous material layers 156, 158 in addition to the porous material layer 114. Examples of which are depicted in fig. 8 and 9.

At this point, it should be noted that when the porous material is dry, the porous material may be considered to be in an "air delivery state" in which air is delivered through each dry pore of the porous material. The "liquid delivery state" corresponds to a liquid, such as water, being delivered through the (wetted) pores of the porous material. When there is no more liquid supplied to the hole(s), a "fluid blocking state" may be employed. The "fluid blocking state" corresponds to a state in which the surface tension of the (residual) liquid remaining in the wetted pore(s) of the porous material prevents the transport of fluid through the pore(s). In the latter state, a surface or barrier is created at the boundary between air and liquid (e.g., water). The barrier may help to maintain the above-described under-pressure in the dirty inlet(s) 142A, 142B. The pressure required to "break" the barrier may be referred to as the "burst pressure".

It should be noted that woven porous fabrics with finer weave may have smaller pores, such as micropores, resulting in higher burst pressures. However, there may be limitations on how to make the apertures using braiding techniques. At the same time, it is possible that certain fibers, such as those selected for their advantageous cleaning and/or abrasion properties, may only be woven to provide a more open structure that is not suitable for maintaining adequate under-pressure in the soil inlet(s) 142A, 142B.

However, the "burst pressure" may be adjusted in various ways. In the non-limiting example shown in fig. 8, the porous material includes the porous material layer 114 and the further first porous material layer 156 or is defined by the porous material layer 114 and the further first porous material layer 156.

For example, the porous material layer 114 is a microfiber fabric and the additional first porous material layer 156 is a microfiber fabric.

By a porous material comprising a stack of porous material layers 114, 156 in this way, the burst pressure may be increased, for example, relative to a case where the porous material consists of only porous material layers 114.

Without wishing to be bound by any particular theory, it is believed that this effect results from variations in pore size and shape, such as statistical variations. For example, microfiber fabrics may be made from a number of fibers and yarns that are woven together into a fabric sheet. Holes, such as micropores, may be created between the fibers and yarns, so that the size of the holes present in the fabric are not precisely fixed to a size and shape, but vary statistically.

The single porous material layer 114 may include a small number of relatively large pores (with a small surface tension of the residual liquid for these pores) such that these relatively large pores contribute to a lower burst pressure of the single porous material layer 114. By stacking additional porous material layers 156 over porous material layer 114, the above-described few relatively large pores of porous material layer 114 may be relatively less likely to align/communicate with relatively large pores included in additional porous material layers 156. Thus, the stacking of the porous material layers 114, 156 may help to increase the burst pressure of the porous material.

Although in the non-limiting example shown in fig. 8 the porous material is formed of the porous material layer 114 and the further first porous material layer 156, more than one further porous material layer 156 may be included in the porous material, for example to further increase the burst pressure. In the non-limiting example shown in fig. 9, the porous material includes a porous material layer 114, an additional first porous material layer 156, and an additional second porous material layer 158, or is defined by the porous material layer 114, the additional first porous material layer 156, and the additional second porous material layer 158.

For example, the porous material layer 114 is a microfiber fabric, the additional first porous material layer 156 is a microfiber fabric, and the additional second porous material layer 158 is a microfiber fabric.

The porous material layers 114, 156, 158 of porous material may or may not adhere to each other. In a non-limiting example in which the porous material layers 114, 156, 158 adhere to one another, for example, via a suitable adhesive applied between the porous material layers, this may help to further increase the burst pressure of the porous material.

Without wishing to be bound by any particular theory, this is believed to be due to the adhesive impeding horizontal fluid transport between the adhered porous material layers. Turning to fig. 10, fluid transport through the pores 160a,160b of the porous material layer 114 is schematically depicted in the upper left square, while horizontal fluid transport between the non-adherent porous material layer 114 and the pores 162A of the further first porous material layer 156 is schematically depicted in the lower left square. Comparing the latter to the right hand square of fig. 10, it is apparent that the adhesive 164 between the porous material layer 114 and the further first porous material layer 156 limits or prevents horizontal fluid transport between the pores 160A of the porous material layer and the pores 162A, 162B of the further first porous material layer 156.

Any suitable adhesive 164 may be used to adhere the porous material layers 114, 156, 158 to one another, such as a heat activated fabric glue. Commercially available examples of heat activated fabric gels are

An advantage of the porous material layers 114, 156, 158 of the porous material not adhering to each other may be that the resistance to the transport of liquid through the porous material may be reduced, for example by allowing a horizontal transport of liquid between the porous material layers 114, 156, 158 or at least restricting a horizontal transport of liquid between the porous material layers 114, 156, 158 less than if the adhesive 164 were present between the porous material layers 114, 156, 158.

Alternatively or in addition to the porous material comprising one or more further porous material layers 156, 158 in addition to the porous material layer 114, the porous material layer 114 (e.g. a microfiber fabric) may be subjected to a densification treatment, for example by ultrasonic welding. This helps to increase the burst pressure of the porous material layer 114.

In an exemplary densification process, a porous material layer 114 (e.g., a porous fabric, such as a microfiber fabric) is placed (e.g., compressed) between two elements (e.g., rollers) and relatively high frequency (e.g., about 40 kHz) vibrations are emitted into the porous material layer 114.

Such vibration may cause the fibers of the porous fabric (e.g., microfiber fabric) to move and rub against each other, generating heat, which may cause individual fibers to be welded together. Such welding may be controlled so as to provide a more dense porous structure rather than a dense solid mass. Since this process can be performed while the porous fabric is in a compressed state, the density of the fabric can be increased, thereby increasing the burst pressure.

Such densification processes may alternatively or additionally be used to densify one or more of the additional porous material layers 156, 158 when the additional porous material layer(s) 156, 158 are included in the porous material.

Fig. 11 schematically illustrates an exemplary test device 166 for testing the burst pressure characteristics of a porous material 168. The porous material 168 is sandwiched between the clamping member 170 and the base plate 172. The clamping member 170 defines a hole for a bolt 174, the bolt 174 being received in a threaded hole in the base plate 172. Turning the bolt 174 in the appropriate direction can clamp/unclamp the porous material 168.

In this particular example, the clamping member 170 is an aluminum ring having a thickness of 10mm, and the base plate 172 is made of poly (methyl methacrylate) having a thickness of 10 mm. The sample of porous material was a disc 140mm in diameter. Eight bolts 174 were used to secure the sample.

The contamination inlet 142A in the test apparatus 166 is defined by an opening of a delivery conduit 176 disposed in the base plate 172. In the cavity between the porous material 168 and the dirt inlet 142A, the liquid transport support structure 154 described above is provided, in this case in the form of a mesh of 80mm diameter.

The testing device 166 includes an under-pressure generator 178 for generating an under-pressure in the dirty inlet 142A, and a pressure sensor 180, such as a pressure gauge, arranged to measure the pressure in the dirty inlet 142A.

In this particular example, the pressure sensor 180 includes a data acquisition unit 2) A pressure gauge is incorporated to be able to monitor the pressure as a function of time.

In this particular example, the under-pressure generator 178 is in the form of a peristaltic pump or a syringe pump, such as a 250mL syringe pump. Peristaltic pumps may provide a pulsed flow of water. Syringe pumps were found to allow more accurate measurements than peristaltic pumps.

The testing device 166 also includes a pressure line filter 182 in the form of a chamber that is configured to prevent liquid from entering a pressure sensor line 184 connecting the pressure line filter 182 and the pressure sensor 180. Downstream of the pressure line filter 182 and the pump 178 is a collection reservoir 186 for collecting liquid pumped through the porous material 168.

The test procedure included clamping a sample of porous material 168 between clamping member 170 and substrate 172, and then setting pump 178 to deliver 100cm ³ Flow rate per minute. The pressure line filter 182 is checked to ensure that it is empty, and the manometer of the pressure sensor 180 is zeroed and reconnected prior to each measurement. Then 25cm is used ³ Is poured onto the sample of porous material 168, onto the porous materialLeaving a water layer of about 4mm in depth. A flushing operation is then performed by activating the pump 178 so that water is drawn through the sample of porous material 168. After the flush operation, the pump 178 is stopped and 25cm is used ³ Is poured over the sample of porous material 168 and a measurement run is performed by triggering the data acquisition unit to begin data acquisition and to activate pump 178.

An exemplary plot of under-pressure versus time from data acquisition is provided in fig. 12, along with a schematic illustration of a porous material 168. Initially, the "liquid delivery state" 188 described above is employed, wherein a liquid 190 (water in this example) is delivered through the (pre-wetted) apertures 192. The "delivery pressure" recorded in this case corresponds to the pressure differential required to deliver the liquid 190 through the porous material 168 and the reticulated liquid delivery support structure 154.

The control equation describing the "fluid delivery state" 188 may be the following poiseuille equation:

where ΔP is the pressure differential across orifice 192; η is the dynamic viscosity of the liquid; l is the length of the hole 192; phi is the volumetric flow rate; and r is the radius of the hole 192.

For example, assuming a pore diameter of 20 μm, the pores extend through the porous material 168 having a thickness of 0.8mm, the estimated volumetric flow rate is about 4.96 x 10 ^-14 m ³ Per well 192/s (from 100 cm) ³ Typical fluid flow per minute), and eta _{Water and its preparation method} Is 1 x 10 ^-3 Pa·s，ΔP＝10.1Pa。

After the "liquid delivery state" 188, an intermediate state 194 is employed in which substantially all of the liquid 190 has been removed from the surface of the sample of porous material 168 such that most of the pores are in the "fluid blocking state" described above, wherein the surface tension of the (residual) liquid 190 remaining in the wetted pore(s) of porous material 168 prevents air 196 from being delivered through the pores 192. In the intermediate state 194, the decreasing number of apertures 192 may be in a "liquid delivery state". The "fluid blocking state" allows for a significantly higher under-pressure, and therefore the under-pressure increases relatively rapidly during the intermediate state 194, as shown.

The control equation describing the "fluid blocking state" may be the following drop dP equation:

where Pi is the internal pressure, P _O Is the external pressure and R is the fluid drop radius, as schematically shown in fig. 12. T is the surface tension.

For example, assume that for a typical 20 μm diameter hole 192, R is 10 μm and T _{Water and its preparation method} 0.073N/m, P _i －P _O ＝ΔP＝14600Pa。

When detergent is added to water, the Δp may increase to 18000Pa. When the detergent is added, the water surface tension decreases (T _{Soapy water} 0.045N/m) at which time two surfaces are created in the bubble on the hole 192: the inside and outside of the bubble. Thus, the burst pressure in the case where detergent is added to water may be about twice that of a single layer surface:

after intermediate state 194, an end state 198 is employed in which all free water has been removed from the surface of porous material 168 and all pores 192 are initially in a "fluid blocking state". As the pump 178 continues to draw water through the porous material 168, an under-pressure is increased, which may cause some of the fluid pieces to break, causing air 196 to be delivered through the respective holes 192 in an "air delivery state". The associated air ingress may reach equilibrium in end state 198, where the applied flow results in an under-pressure that no longer causes the fluid mass to rupture. The latter corresponds to the "cracking pressure" of the porous material 168 under investigation.

The control equation describing the "air delivery state" may be the poiseuille equation provided above for the "liquid delivery stateAnd (5) processing. For example, assuming a pore diameter of 20 μm, the pores extend through the porous material 168 having a thickness of 0.8mm, the estimated volumetric flow rate is about 4.96 x 10 ^-14 m ³ Per well 192/s (from 100 cm) ³ Typical fluid flow per minute), and eta _{Air-conditioner} Is 18.1 x 10 ^-6 Pa·s，ΔP＝0.18Pa。

In general, both the air delivery pressure (e.g., 0.18 Pa) and the water delivery pressure (e.g., 10.1 Pa) may be significantly smaller, e.g., negligible, compared to the pressure differential created by the surface tension (e.g., 14600 Pa).

Fig. 13 provides several pressure-time diagrams of porous materials 168 tested using the test apparatus 166 and test procedures described above. Curve 200 is for porous material 168 having only porous material layer 114; curve 202 is for porous material 168 having porous material layer 114 and further first porous material layer 156; curve 204 is for a porous material 168 having a layer of porous material 114, a further layer of first porous material 156 and a further layer of second porous material 158; and, curve 206 is for a porous material 168 having a porous material layer 114 and three other porous material layers. These data indicate that including more stacked porous material layers in the porous material 168 increases the cracking pressure, as previously described.

Further, each curve in the set of curves 202, 204, and 206 is a curve for the porous material 168, wherein the porous material layers adhere or do not adhere to each other. It was observed that the use of an adhesive to adhere the porous material layers to each other further increased the burst pressure, as described above.

Fig. 14 schematically illustrates the "liquid delivery state" 188 described above, wherein liquid is pumped through all of the apertures 192 in a), the end of the liquid delivery state 188 in b), the intermediate state 194 in c), and the end state 198 in d). The porous material 168 is shown in fig. 14 covering the dirty inlet(s) 142A, 142B connected to an under-pressure generator 178 (e.g., a pump).

The porous material 168 has pores 192, such as micropores, each having a different burst pressure. The latter is represented in fig. 14 by the numbers provided below each hole 192. For simplicity, each number is rounded to a single number.

Upon activation of the under-pressure generator 178 (e.g., pump), all liquid (e.g., water) is drawn from the floor and the desired pressure is the water delivery pressure, set to "1" in this example. The under-pressure in the dirty inlet 142A, in this example in the cavity 150 behind the porous material 168, is correspondingly "1". Thus, a) in fig. 14 schematically represents the "liquid delivery state" 188, and b) shows the end of the "liquid delivery state" 188. In b), the point at which the under-voltage starts to rise is reached.

When all of the liquid, such as water, has been removed from the floor, all of the holes 192 may be blocked by the surface tension of the residual liquid therein. In the non-limiting example shown, the under-pressure generator 178 is a fixed flow pump, so continued operation of the pump may increase the under-pressure. At some point, the under-pressure in the dirty inlet 142A behind the porous material 168 may rise to a level of the fracture pressure of the weakest aperture 192, e.g. "4", the fracture pressure of the aperture will be exceeded and air may begin to be delivered therethrough. Since the pressure in the dirty inlet 142A behind the porous material 168 may already be significant when the first holes 192 "burst" at this point, the air delivered through the holes 192 may be significant. Thus, step c) in fig. 14 may be regarded as schematically representing intermediate state 194.

In intermediate state 194, holes 192 may become plugged while other holes 192 still deliver liquid from other areas (away from dirty inlet(s) 142A), thus creating more under-pressure near dirty inlet(s) 142A. This may cause the underpressure to rise relatively slowly until all free liquid has disappeared. This may all be affected by the pump speed, and in at least some examples, the characteristics of the liquid delivery support structure 154, along with the flexibility of all elements, deform upon application of an under-pressure.

As a simplified illustration, if the flow rate is set to 100cm ³ Per minute, neglecting the flow resistance between the porous material and the pump, and all elements being infinitely rigid, the intermediate state 194 may be a vertical line in fig. 12, moving digitally from the "liquid delivery state" 188 to the final stateState 198.

This process may continue until the delivered air is equal to the pumping rate in this example, and the under-pressure in the dirty inlet 142A behind the porous material 168 is below the cracking pressure of the remaining "unbroken" pores 192 having the lowest cracking pressure. Thus, step d) in fig. 14 may be regarded as schematically representing the above-described end state 198.

It should be noted that the pressure measured in the test device 166 may define the burst pressure of the porous material 168. Different flow rates have been tested, for example 150cm ³ Per minute, but shows the same burst pressure, it is noted that more holes 192 may "burst" to compensate for the increased flow.

The pore size (in other words, pore diameter) of the pores 192 of the porous material 168 may be selected so as to balance a relatively high under-pressure with a relatively low liquid delivery resistance/liquid delivery pressure of the porous material 168.

The smaller holes 192 may increase the under-pressure created in the dirty inlet 142A, for example, with the relatively low power under-pressure generator 178 (e.g., pump). The denser porous material 168 with smaller pores 192 may produce higher burst pressures. Also for the purpose of investigating the lower limit of pore size, an investigation was conducted using the above-described test device 166 and test program using a beer filter specified according to its retainable particle size as the porous material 168: 0.25 μm, 3 μm, 10 μm and 25 μm filters were tested. For this experiment, it was assumed that the latter beer filter specification was the same as "pore size/diameter".

Referring to fig. 15, curve 208 is for a 0.25 μm filter; curve 210 was for a 3 μm filter; curve 212 is for a 10 μm filter; curve 214 is for a 25 μm filter; curve 216 is used to reference the microfiber fabric.

As can be seen from fig. 15, the porous size/diameter of the porous material 168 has a significant impact on performance. From the results, it is estimated that the average 40 μm pore diameter/diameter of the porous material 168 (e.g., equivalent to a 40 μm beer filter) may correspond to a maximum based on under-pressure considerations.

The average 0.25 μm pore diameter/diameter of the porous material 168 (e.g., equivalent to a 0.25 μm beer filter) may correspond to a minimum value based on liquid delivery pressure considerations.

It is evident from fig. 15 that a 0.25 μm filter may result in a situation where the water delivery pressure is significantly higher than a 3 μm filter. In the case of a 0.25 μm filter, the under-pressure may rise to about 23000Pa during water delivery. Furthermore, for a 0.25 μm filter, the time to reach a dry state may be significantly longer, which means that it may take significantly more time to transport liquid/water from the surface to be cleaned.

In a non-limiting example, an average pore size/diameter of about 3 μm (e.g., corresponding to a 3 μm beer filter) of the porous material 168 may provide an advantageous balance of properties.

Fig. 15 shows that there is a limited difference between the liquid/water delivery pressure and the burst pressure of the porous material 168. The relatively small holes 192 may result in an increase in burst pressure, for example up to 39000Pa in the case of a 0.25 μm filter, but may also result in an increase in water/liquid delivery pressure, for example up to 33000Pa in the case of a 0.25 μm filter. It should be noted that the difference between the water delivery pressure and the burst pressure was similar to the difference of the reference microfiber fabric (1000 Pa water delivery pressure; 7000Pa burst pressure).

Bacteria tend to be characterized as having relatively small dimensions. For example, E.coli (Escherichia coli) cells, which are about 2 μm long and 0.5 μm in diameter.

Thus, a porous material 168 having a pore size greater than 2 μm may allow such bacteria to pass through. In this way, bacteria can be removed from the surface to be cleaned.

Depending on the porous material 168 selected, up to 99.9% of the bacteria may be drawn away from the surface to be cleaned through the porous material 168.

In some embodiments, the porous material 168 is defined by one or more layers of a microfiber fabric having pores with a pore size/diameter in the range of 0.25 μm to 40 μm (e.g., equivalent to a 0.25 μm to 40 μm beer filter).

For example, such porous material 168 (defined by one or more layers of microfiber fabric) may have a pore size/diameter distribution in the range of 0.25 μm to 40 μm described above, and an average pore size of 20 μm to 40 μm, such as about 35 μm. Since the pores are sized significantly larger than the bacteria, the bacteria can pass through the porous material 168 to be removed from the surface to be cleaned.

While the above description focuses on the principle of operation of the porous material 168, it should be noted that the porous material 168 may be in contact with and move over the surface to be cleaned at a certain speed. This is schematically illustrated in fig. 16, fig. 16 shows an exemplary cleaning head 100 that includes a soil inlet 142A covered with a porous material 168 over a surface 218 to be cleaned. In this non-limiting example, the surface 218 to be cleaned is a surface of a floor 220, and a liquid layer 222, such as water, is present between the surface 218 to be cleaned and the porous material 168. An under-pressure generator 178, such as a pump, is used to draw fluid through the pores 192 of the porous material 168 in the direction of arrow 224. Arrow 226 represents an internal under-pressure drawing liquid toward the dirty inlet 142A. Arrow 228 represents the speed of the cleaning head 100.

Fig. 16 schematically illustrates a velocity profile 234 in the fluid layer 222. Arrow 230 represents the fluid shear force on porous material 168 created by velocity profile 234 in fluid layer 222. Arrow 232 represents the shear force pulling the water toward the floor 220.

This behavior can be approximated using the following bernoulli equation:

where ρ is the density of the fluid, v is the fluid flow rate, P is the pressure, h is the height above the reference plane (in this case the floor 220), and g is the acceleration due to gravity.

The Bernoulli equation described above may be rewritten for the pressure below the porous material 168:

for a speed of 1.5m/s, Δp=1125pa; for a speed of 3.16m/s Δp=5000 Pa.

This indicates that at higher speeds more liquid will remain on the floor 220, as at higher speeds the floor 220 will pull the liquid more strongly, and this has been observed with the cleaning head 100 according to the present disclosure.

Movement of the cleaning head 100, for example at a speed of about 1.5m/s, may create a shear flow in the liquid layer 222, creating a shear force 232 acting on the liquid in the porous material 168, which pulls the liquid toward the surface 218 to be cleaned. The water is also forced in the direction of the dirt inlet 142A by the under-pressure 226. The under-pressure may be selected such that the force moving the liquid 222 toward the dirty inlet(s) 142A exceeds the shear force 232.

The liquid pick-up performance of the exemplary cleaning head 100 was evaluated, the cleaning head 100 comprising a porous material 168 and cleaning liquid applicator materials 126, 128, the cleaning liquid applicator materials 126, 128 being used to apply liquid (e.g., water) to the surface 218 to be cleaned, the cleaning liquid applicator materials 126, 128 moving over the surface 218 to be cleaned at a speed of 1.5m/s and having different dirty inlet underpressures. The results are shown in Table 1.

TABLE 1

Another advantage of the liquid pick-up principle described herein may be lower power consumption, particularly in the example where the under-voltage generator 178 is powered.

Conventional vacuum cleaners capable of picking up water require the generation of significant airspeeds and/or brushing forces in order to create sufficient shear forces on the water droplets to cause them to enter the vacuum cleaner. Typical power consumption values for such vacuum cleaners are of the order of hundreds of watts.

The following calculations show the relatively low mechanical power required for liquid (e.g., water) pick-up according to the present disclosure.

P＝Φ*ΔP

Wherein P is mechanical power in watts; phi is m ³ Fluid of/s meterA flow rate; and Δp is the under-pressure in Pa in the fouling inlet(s) 142A.

For example, under pressure of 5000Pa and 100cm ³ Fluid flow per minute, power 8.3 x 10 ^-3 A tile.

If the under-voltage generator 178 is powered using a conventional battery that provides a 28 minute run time, for example in a wet cleaning device with a mechanical power consumption of about 50 watts, the run time in the present case will be 168000 minutes, in other words, more than 100 days.

Thus, an electric wet cleaning device having a cleaning head 100 according to the present disclosure may require only little recharging of its battery (in examples including such a battery to power the wet cleaning device) and/or may be lighter due to the minimum battery capacity required for a 1 hour run time, for example. With respect to the latter, it is noted that batteries for conventional hand-held wet cleaning devices may weigh about 0.5kg and thus may significantly increase the overall weight of the wet cleaning device.

Table 2 provides a mechanical power comparison between a conventional vacuum cleaner and the various conditions described above with respect to a wet cleaning apparatus according to the present disclosure.

TABLE 2

More generally, the present invention provides a wet cleaning apparatus comprising a cleaning head 100. The cleaning head 100 has at least one dirty inlet 142A, 142B and a porous material 168 covering the at least one dirty inlet 142A, 142B. The wet cleaning device further comprises an under-pressure generator 178, the under-pressure generator 178 being configured to provide a pressure difference between the interior of the wet cleaning device and atmospheric pressure for drawing fluid through the porous material 168 and into the at least one dirty inlet 142A, 142B.

In some embodiments, the pressure differential is in the range of 2000Pa to 13500 Pa.

Both end points of the range of 2000Pa to 13500Pa for the pressure difference are purposefully selected.

The 2000Pa lower limit reflects that the cleaning head 100 will typically move over a surface to be cleaned, such as a floor, and as the speed of the cleaning head 100 over the floor increases, the accompanying drop in static pressure means that the liquid is pulled toward the floor. As described above, this behavior can be approximated by the bernoulli equation.

Referring to table 1 above, it has been found that when the cleaning head 100 is moved over a surface to be cleaned at typical speeds, at below 2000Pa, excess liquid may remain on the surface to be cleaned.

A minimum under-pressure of 2000Pa is set accordingly, depending on the minimum typical speed at which the user moves the cleaning head 100 over the surface to be cleaned, ensuring that the under-pressure is sufficient to draw liquid into the interior of the wet cleaning apparatus, without the user having to significantly slow down or stop the movement of the cleaning head 100 over the surface to be cleaned in order to pick up liquid.

The upper limit of 13500Pa is defined to ensure that the liquid transport through the porous material 168 is sufficiently fast.

There is a tradeoff between the magnitude of the under-pressure that can be maintained and the resistance to flow through the porous material 168, which determines the rate at which liquid can pass through the porous material 168. This tradeoff is reflected in the selection of the upper 13500Pa for this range.

In some embodiments, the pressure differential is 2000Pa to 12500Pa, preferably 5000Pa to 9000Pa, and most preferably 7000Pa to 9000Pa. These ranges may reflect the particularly enhanced liquid pick-up observed during movement of the cleaning head 100, coupled with the relatively low flow resistance through the porous material 168.

This pressure differential can be directly and positively verified in a given wet cleaning device by, for example, drilling holes in the tube of the wet cleaning device that is fluidly connected to the dirty inlet(s) 142A, 142B and using the holes to couple to the pneumatic pressure sensor itself, which has a tube with a membrane covering its ends; thus using an airtight connection to connect the sensors. The sensor may be arranged to avoid disturbing the flow, so that a person skilled in the art will arrange the sensor to avoid e.g. generating a bypass flow. No flow flows to or from the sensor: only pressure is transmitted. In this way, the flow of the appliance is never compromised (and therefore can remain at a set level despite the sensor installed).

The pressure sensor is connected between the porous material 168 and the under-pressure generator 178 and is as close as possible to the porous material 168 to minimize the effects of other factors (e.g., flow resistance, etc.) on the sensed differential pressure.

The sensing element/membrane of the pressure sensor/gauge is desirably arranged/positioned in the pressure sensor such that the sensing element can be placed directly (without the need for a connecting tube) in the tube or in the cavity 150 behind the porous material 168.

As will be appreciated by those skilled in the art, by positioning the membrane of the pressure sensor (in other words, the membrane manometer) such that the membrane is positioned at (in other words, in line with) the wall of the tube (or exposed to the cavity 150), measurement errors can be minimized.

It should be noted that bubbles within the narrow tube can create drag (capillary/surface tension effect) and thus can affect the measurement. Thus, those skilled in the art will further appreciate that air bubbles (water-air surfaces) should also be noted that do not unduly affect differential pressure measurements.

It should also be noted that the water column present between the pressure sensor and the porous material 168 should be subtracted from the measurement (if such a water column is present during measurement) to compensate for the static pressure generated by the water column.

Once the pressure sensor is arranged as described above, it can be determined that the maintenance of the under-pressure is due to the porous material 168 and not some other element, such as a valve. Any such element that affects the under-pressure presented to the porous material 168 should become inoperable for the purpose of performing the measurement.

When performing the pressure differential measurement, the component(s) dispensing the cleaning liquid (if the wet cleaning device is configured to deliver the cleaning liquid) is disengaged.

The wet cleaning device is turned on (at the desired setting) so that the pick-up system including the under-voltage generator 178 is activated. Recording of data from the pressure sensor is started.

The pick-up area of the cleaning head 100 is suspended in a layer of water having a maximum depth of 5 mm.

The pick-up area is then lifted from the water without tilting it in any way (so that the cleaning head 100 remains in the cleaning position as if it were positioned to clean the floor) so that the water no longer contacts the porous material 168. At this point, the "free water" will be removed from the porous material 168, all of the pores will enter their "blocked state", and the burst pressure is determinable. The measurement will be similar to the graph shown in fig. 12, again noting that equilibrium is established in the end state 198, where the applied flow results in an under-pressure that does not cause more fluid pieces to break.

The burst pressure obtained from this measurement, referring to end state 198, is the "pressure differential between the interior of the wet cleaning apparatus and the atmospheric pressure used to draw fluid through porous material 168 and into at least one of the dirty inlets 142A, 142B". It was verified whether the range of 2000Pa to 13500Pa was satisfied based on the measurement results.

It should be noted that the porous material 168 may be arranged to contact a liquid on the surface to be cleaned, as previously described. Thus, the porous material 168 may be defined from an outer surface of the porous material 168 that may be exposed to liquid on the surface to be cleaned to an inner surface of the porous material 168 that is exposed to at least one dirty inlet.

ASTM F316-03,2019, test A provides bubble point pressure measurements. While this standard method was developed for non-fibrous membrane filters, the procedure may be replicated for porous material 168 according to the present disclosure.

Briefly, a bubble point test for determining the limiting pore diameter, in other words the maximum pore diameter, is performed by pre-wetting a sample of the porous material 168, increasing the gas pressure upstream of the porous material 168 at a predetermined rate, and observing the gas bubbles downstream to indicate the passage of gas through the largest diameter pores of the porous material 168.

As with the membrane filter described in ASTM F316-03,2019, test a, the porous material 168 may have discrete pores extending (at least approximately) from one side of the porous material 168 to the other, similar to capillaries. The bubble point test is based on the following principle: the wetting liquid is held in these capillary holes by capillary attraction and surface tension, and the minimum pressure required to force the liquid out of these holes is a function of the hole diameter. The pressure at which a steady bubble flow occurs in this test is referred to as the "bubble point pressure".

It should be noted that ASTM F316-03, 2019, test a is based on the pore approximation being a capillary pore having a circular cross section, and therefore the limiting pore diameter should be considered to be an empirical estimate of the maximum pore diameter based only on this premise.

As with the test procedure, ASTM F316-03, 2019 was replicated for the test device specified in test a.

1. Samples of porous material (2 inch (50.8 mm) diameter; held in a circular holder (e.g., having an opening/active area of 47mm diameter) were fully wetted by floating them on a liquid pool (note that a vacuum chamber could be used to help wet the sample if desired.) for water wettable samples, the samples were placed in water and fully wetted.

2. A wetted sample of porous material was placed in the filter holder of the test device.

3. Placing a fine mesh (100 x 100 mesh) over a sample of porous material; the fine mesh is the first part of the standard specified 2-layer construction.

4. A second part in the form of a perforated metal part in a 2-layer construction of increased rigidity is placed on the fine mesh.

5. The support rings are placed on the stack and bolted in place. A slight gas pressure may be applied at this point to eliminate possible liquid reflux.

6. The perforated metal parts were covered with 2mm-3mm of test liquid (type IV water, standard requirements when the sample was wetted with water).

7. The gas pressure was then raised and the lowest pressure at which the steady stream of bubbles rose from the central region of the reservoir was recorded (see ASTM F316-03, 2019, fig. 5 of test a; note that the bubbles observed at the edge of the reservoir were ignored for bubble point determination).

It was found to be suitable to first raise the pressure relatively quickly (e.g. at about 200 Pa/sec) to roughly determine the bubble point. The pressure is then released from the sample to allow water to flow back into the sample. The pressure was then raised to about 80% of the expected pressure value, held at 80% level for about 15 seconds (to ensure that all "free" water was forced out of the sample), and then raised again at a lower rate of less than or equal to Pa/sec until a constant bubble flow was observed.

Equation 1 of test a was then used to determine the limiting pore diameter d from the recorded bubble point pressure p using ASTM F316-03, 2019: d=cγ/p, where γ is the surface tension in mM/m (72.75 for distilled water at 20 ℃) and C is 2860 when p is in Pa.

The bubble point pressure from ASTM F316-03, 2019, test a was found to be comparable to the burst pressure described above for the sample of porous material 168, except for the case of a 0.25 μm beer filter, which can be directly explained by the forced flow present in the burst pressure test, rather than in the bubble point test. The results for the various porous material 168 samples are provided in table a.

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Table A

In some embodiments, the ultimate pore diameter of the porous material 168 measured using ASTM F316-03, 2019, test a is equal to or greater than 15 μm.

Such a limiting pore diameter of 15 μm or greater may help to maintain a relatively large under-pressure while ensuring that the pores are large enough to effectively deliver liquid. Regarding the latter, it should be noted that this observation is supported by theory, noting that the flow resistance can be increased to a power of 4 for smaller holes when approximated using the poiseuille equation provided above.

In some embodiments, the ultimate pore diameter of the porous material 168 measured using ASTM F316-03, 2019, test a is equal to or less than 105 μm. The upper limit of the limiting pore diameter helps ensure that the porous material 168 can maintain a sufficient under-pressure.

As described above, ASTM F316-03, 2019, test A employed cylindrical holes. For purposes of explanation/illustration only (and thus should not be considered as limiting the limiting hole diameter from ASTM F316-03, 2019, test a provided herein), it should be noted that the limiting hole diameter can be adjusted with a Tortenoise Factor (TF), which is an empirical factor derived from solid wire filters, to compensate for non-circularity of the holes. The 1.3-1.65 expansion of TF suggested in ASTM E3278-21 (see section 4.2.1 of the standard) may result in a pore size expansion of about 27%. For illustrative purposes only, table B shows the above limiting hole diameter endpoints when TF adjustment is used. Note that ASTM F316-03, 2019, the limiting pore diameter of test a provides a measure of the maximum pore size that particles pass through, so TF can compensate for the fact that "triangular" pores can only pass through spherical particles that are much smaller than triangular surfaces.

Table B

In some embodiments, the under-voltage generator is configured to provide less than or equal to 2000cm ³ Flow rate per minute through porous material 168.

Such a flow rate may be significantly lower than the flow rate of the conventional wet vacuum cleaner described above. Since the power is equal to the flow rate multiplied by the pressure difference, by dividing the maximum by 2000cm ³ The combination of the/minute flow rate and the maximum 13500Pa differential pressure described above as the maximum power consumption scheme minimizes the power consumption of the wet cleaning apparatus. Referring to Table 2 above, this allows for a wet cleaning packageThe device can be made relatively compact, for example using smaller batteries, and/or have a relatively long run time.

Alternatively or additionally, the under-voltage generator may be configured to provide a voltage equal to or greater than 15cm ³ Flow rate per minute through porous material 168. This may help to pick up liquid from the surface to be cleaned quickly enough. In some embodiments, 15cm ³ The lower limit of/min may be set to equal or exceed the flow rate of cleaning liquid from the cleaning liquid outlet(s) 104 also included in the cleaning head 100.

In some embodiments, the under-voltage generator is configured to provide a voltage equal to or greater than 40cm ³ Flow rate per minute through porous material 168. In addition to facilitating efficient liquid pick-up, in some embodiments, the 40cm ³ The/minute may be set to equal or exceed the flow rate of the cleaning liquid from the cleaning liquid outlet also included in the cleaning head, the minimum cleaning liquid flow rate being set to ensure adequate supply of the cleaning liquid to the surface to be cleaned.

The under-voltage generator may be configured to provide 80cm through the porous material ³ Per minute-750 cm ³ Per minute, more preferably 100cm ³ Per minute-300 cm ³ Per minute, most preferably 150cm ³ Per minute-300 cm ³ Flow rate per minute. Such a flow rate may take advantage of the under-pressure retention capability of the porous material 168 and may ensure adequate liquid pick-up while limiting energy consumption.

In some embodiments, the porous material 168 has a thickness of less than or equal to 10mm, more preferably less than or equal to 5mm, and most preferably less than or equal to 3mm. Such a maximum thickness may help minimize the flow resistance through the porous material 168.

The thickness of the porous material 168 may be determined by using a 0.01mm precision gauge and two grounded metal plates for receiving the porous material 168 therebetween (the upper plate through which a positive pressure is applied is 70mm x 30mm, and the lower plate on which the porous material sample is supported has a larger area than the 70mm x 30mm surface of the upper plate to facilitate alignment). The arrangement is configured to provide a sample of porous material (70 mm by 30mm ) Applying 864.2N/m ² Is a pressure of the pressure sensor. Relevant measurement parameters are shown in table C:

table C

Using this method, the thickness of several samples was determined and the data is provided in table D:

table D

In some embodiments, at 200cm ³ The fluid transport pressure per minute flowing through the porous material 168 is less than 0.25 times the bubble point pressure as determined by ASTM F316-03, 2019, test a.

This may mean that the flow resistance through the porous material 168 is kept at a relatively low level.

Another set of burst pressure tests (similar to the tests described above) was performed using porous materials corresponding to sample number 18 in table a, sample numbers 22-25 in table D, and a 0.8mm thick vendor F fabric. The flow pressure drop and burst pressure of each sample were recorded and the results (average of at least two measurements) are listed in table E. In these experiments, 89cm was used ³ Flow rate/min, and the diameter of the circular mesh under the sample (extending through the "active area" of the sample) was 80mm.

Porous material sample numbering/description	Flow pressure drop/Pa	Burst pressure/Pa
			15	19000	13920
A vendor F fabric; thickness of 0.8mm	120	5539
			22	2910	11495
23	8921	12405
			24	12359	13000
25	15830	13363
			26	16617	14100
27	18127	14173

Table E

It can be seen that the burst pressure increases as more layers are stacked on top of each other, as previously described. However, when more layers are added, the delivery flow pressure may increase faster than the burst pressure, and in the case of sample nos. 22 to 27, when the porous material has four stacked bilayers (at sample No. 25), the delivery flow pressure exceeds the burst pressure.

The delivery flow pressure rises faster with more layers than evident from samples 22 to 27; however, air in the system may mean that the data starts to show compressibility, especially for sample numbers 25 to 27.

More generally, the data may indicate that the wet cleaning device may be operated when the delivery flow pressure (at the desired flow rate) is below the burst pressure.

For the tests whose results are listed in Table E, the flow rate was 89cm ³ Per minute, the effective area of the fabric was 5030mm ² . In the case of the cleaning head 100, the effective area may be about 1750mm ² . Thus, when a delivery flow pressure is applied to the porous material 168 of the cleaning head 100, the actual flow through the porous material 168 may be 0.35 times lower (1750/5030) than the flow used in these tests.

This may mean that the maximum flow rate that can be tolerated by the porous material 168 is about (0.35 x 98) 31cm at the point where the delivery flow pressure is equal to the burst pressure (e.g., at sample number 24) ³ /min. Even if more layers are added to the porous material 168, the burst pressure may remain approximately the same while the delivery flow pressure increases, thus reducing the value even more.

Note that in the burst pressure test described above, the entire surface of the test sample is covered with water, and thus the entire area of the porous material 168 delivers water. In practice, however, the area of the cleaning head 100 that contacts the floor (e.g., 5mm wide and 350mm long) delivers water, while the area of porous material 168 adjacent to that area may also deliver air. This may mean that when, for example, four bilayers are used (in the case of sample number 25), and the burst pressure of the porous material is lower than the water delivery pressure, the perimeter of the porous material 168 may begin to burst, releasing air, thus resulting in settling at the burst pressure. The active/pick-up area may be kept at a relatively low pressure and thus may pick up liquid relatively slowly, so that liquid may remain on the surface to be cleaned. In contrast, in the case of porous material 168 having a relatively low delivery flow pressure and a significantly greater burst pressure (e.g., in the case of a 0.8mm thick supplier F fabric, where the burst pressure is 50 times higher than the delivery flow pressure), the pick-up flow may be very high.

In summary, the wet cleaning device may operate with a burst pressure higher than the transport flow pressure, but in order to enable pick-up at a higher speed, the burst pressure may be at least twice the transport flow pressure.

In some non-limiting examples, the cleaning head 100 may be 40cm ³ The flow rate per minute delivers the cleaning liquid. At a flow rate through the porous material 168 of 85% of the cleaning liquid flow rate over the smooth surface to be cleaned, i.e. 34cm ³ In the case of a pick-up rate per minute, the pick-up rate may be 31cm from that estimated above for sample number 24 ³ Comparison per minute.

In some non-limiting examples, some tolerances may be introduced, for example to account for 20cm ³ The cleaning liquid flow per minute thus results in an upper limit of the thickness of the porous material 168 of about 5mm (see sample number 25).

As described above, the porous material 168 may include one or more of porous fabric, porous plastic, and foam.

In embodiments where the porous material 168 comprises such porous plastic, one or more additional layers of porous material, including for example porous fabrics, such as woven porous fabrics, may be disposed on the outer surface of the porous plastic. The further porous material layer(s) may be more wettable by water than the porous plastic and thus more suitable for contacting the surface to be cleaned when wetted by water.

Particularly mentioned porous materials include porous woven fabrics, most preferably woven microfiber fabrics. Such a woven microfiber fabric may facilitate achieving a desired under-pressure in a wet cleaning apparatus.

Such porous woven fabrics, particularly such woven microfiber fabrics, may be constructed, particularly by the tightness of their weave, to meet the above-described ranges of limiting pore diameters.

The specifications of a particularly suitable woven fabric are provided as illustrative, non-limiting examples in table F.

Table F

Figures 17-23 schematically illustrate examples of how the porous material 168 is installed in the cleaning head 100.

The porous material 168 may be mounted in any suitable manner. In some embodiments, as shown in fig. 17, the cleaning head 100 includes a support member 236, such as a rigid support member 236, for supporting the porous material 168. The support member 236 may be formed of any suitable material, such as an engineering thermoplastic.

In some embodiments, the cleaning head 100 includes an elastomeric material 238, and the porous material 168 is disposed on the elastomeric material 238. Such elastic deformation of the elastomeric material 238 may reduce the risk of damaging the porous material 168 if, for example, relatively hard protrusions are present on the surface 218 to be cleaned in contact with the porous material 168. Alternatively or additionally, the elastomeric material 238 may help the porous material 168 follow any contour of the surface 218 to be cleaned.

The elastomeric material 238 may be or include, for example, silicone rubber. Other elastomeric materials, such as polydienes, e.g., polybutadiene, thermoplastic elastomers, etc., are also contemplated for inclusion in the elastomeric material 238 or for defining the elastomeric material 238.

Alternatively or additionally, the elastomeric material may be less than 50 shore a, preferably less than 20 shore a, most preferably less than 10 shore a.

In a non-limiting example, the elastomeric material is 4 shore a silicone rubber.

In embodiments where the cleaning head 100 includes a support member 236, such as a rigid support member 236, an elastomeric material 238 may be disposed between the support member 236 and the porous material 168. An example of this is shown in fig. 17.

In embodiments where the cleaning head 100 includes the protruding elements described above, the protruding elements may include an elastomeric material 238, as will be described in more detail below.

Returning to the non-limiting example shown in fig. 17, the impermeable portion 146 is in the form of a polymeric (e.g., thermoplastic) film, wherein the seal 152 is disposed between the polymeric film and the porous material layer 114 included in the porous material 168. Further, the liquid transport support structure 154 included in this particular example is in the form of a mesh or a stack of mesh layers.

In some embodiments, such as the non-limiting embodiment shown in fig. 18, the impermeable portion 146 is defined by impermeable sealing portion(s), such as a plurality of polymeric films, of the porous material layer 114 extending from the elastomeric material 238 to the porous material 168. In this case, it may not be necessary for the polymer film to extend laterally over the inner surface of the porous material layer 114.

In some embodiments, the elastomeric material 238 includes an impermeable portion 146 sealed to the porous material layer 114 of the porous material 168. Therefore, the above-described polymer film and the plurality of polymer films are eliminated in the present embodiment, and may be omitted. In this way, the number of components in the cleaning head 100 may be reduced, thereby facilitating manufacturing.

In some embodiments, as shown in fig. 19, the liquid delivery support structure 154 is provided at least in part or in whole by a surface pattern on and/or in the surface of the porous material layer 114 of the elastomeric material 238 facing the porous material 168. Replacing the web(s) with a surface pattern on the surface of the elastomeric material 238 may help reduce the number of components in the cleaning head 100. In other respects, the example shown in fig. 19 corresponds to the example shown in fig. 18.

In some embodiments, as shown in fig. 20, the support member 236 includes an impermeable portion 146 sealed to the porous material layer 114 of the porous material 168. In other words, the seal existing between the support member 236 and the porous material 168 is provided by the protruding portion of the support member 236 that seals against the porous material 168. Thus, the above-described polymer film is not necessary in this example, as a direct connection between the porous material layer 114 and the support member 236 may be used to create a seal. In other respects, the example shown in fig. 20 corresponds to the example shown in fig. 17.

The non-limiting example shown in fig. 21 corresponds to the non-limiting example shown in fig. 20, except that the liquid delivery support structure 154 is provided at least partially or entirely by a surface pattern on and/or in the surface of the porous material layer 114 of the elastomeric material 238 facing the porous material 168.

The non-limiting example shown in fig. 22 corresponds to the non-limiting example shown in fig. 18, except that an elastomeric material 238 is disposed within a cavity 150 provided between the polymer film as the impermeable portion 146 and the porous material layer 114 of the porous material 168.

The non-limiting example shown in fig. 23 corresponds to the non-limiting example shown in fig. 22, except that the liquid delivery support structure 154 is provided at least partially or entirely by a surface pattern on and/or in the surface of the porous material layer 114 of the elastomeric material 238 facing the porous material 168.

In this regard, it is reiterated that the aforementioned liquid pick-up region PR of the porous material layer 114 (defined around the sealed attachment of the porous material layer 114, e.g., of each of the at least one dirty inlet 142A, 142B) may be arranged relative to each of the at least one cleaning liquid outlet 104 to allow cleaning liquid to bypass the liquid pick-up region PR to reach or at least be directed towards the surface 218 to be cleaned. This arrangement of the liquid pick-up region PR relative to each of the cleaning liquid outlet(s) 104 may be achieved in any suitable manner.

In some embodiments, such as shown in fig. 24, each of the cleaning liquid outlets 104 is disposed in one or more distribution portions that are spatially separated from the porous material layer 114. By arranging the cleaning liquid outlet(s) 104 in such separate dispensing portion(s), the cleaning liquid can be delivered in the direction of arrow 240 in fig. 24 towards the surface 218 to be cleaned without initially contacting the porous material layer 114.

In the non-limiting example shown in fig. 24, the dispensing portion corresponds to the cleaning liquid dispensing strips 108, 124 described above.

In fig. 24, spatial separation is evident by a gap 242, such as an air gap 242, disposed between the porous material layer 114 and the cleaning liquid distribution strips 108, 124.

In some embodiments, as shown in fig. 25, the porous material 168 includes one or more additional porous material layers 156 as described above, and the cleaning head 100 includes a separable element 244, the separable element 244 including one or more additional porous material layers 156, the separation of the separable element 244 separating the one or more additional porous material layers 156 from the porous material layer 114.

In some embodiments, the separable element 244 includes the cleaning liquid applicator materials 126, 128 described above. In this manner, one or more additional porous material layers 156 may be replaced directly at the same time as the cleaning liquid applicator materials 126, 128 are replaced. For example, the cleaning liquid applicator materials 126, 128 may be attached (e.g., adhered) to one or more additional porous material layers 156 in the separable element 244.

In some embodiments, such as in the non-limiting example shown in fig. 25, the cleaning liquid applicator material 126, 128 includes the first and second applicator portions 126, 128 described above, with the first attachment 246A connecting one or more additional porous material layers 156 to the first applicator portion 126 and the second attachment 246B connecting one or more additional porous material layers 156 to the second applicator portion 128. Another example is described below with reference to fig. 33E.

In some embodiments, the cleaning head 100 includes a support for supporting the porous material layer 114, and the cleaning head 100 includes a separable (and/or attachable) member 248, the separable member 248 including the porous material layer 114, the separation of the separable member 248 separating the porous material layer 114 from the support.

Such a separable member 248 may include, in addition to the porous material layer 114, the impermeable portion 146 described above, including, for example, a polymeric membrane or in the form of a polymeric membrane, wherein the at least one dirty inlet 142A is defined by one or more apertures in the impermeable portion 146.

In some non-limiting examples, such as shown in fig. 26, the detachable (and/or attachable) member 248 further includes the liquid transport support structure 154 described above.

For example, a liquid delivery support structure 154 may be disposed in the cavity 150 between the porous material layer 114 and the impermeable portion 146.

When the cleaning head 100 includes both the separable element 244 and the separable element 248, the separable element 244 may be separable, for example, independent of the separable element 248, and the separable element 248 may be separable independent of the separable element 244.

In some embodiments, as shown in fig. 27, the separable member 248 further includes cleaning liquid applicator materials 126, 128. For example, when the separable member 248 includes the impermeable portion 146, the cleaning liquid applicator materials 126, 128 can be attached to (e.g., adhered to) the impermeable portion 146.

In the non-limiting example shown in fig. 27, the cleaning liquid applicator material 126, 128 includes the first and second applicator portions 126, 128 described above, with a first connection 250A connecting a first side of the impermeable portion 146 to the first applicator portion 126 and a second connection 250B connecting a second side of the impermeable portion 146 to the second applicator portion 128.

Fig. 28 schematically illustrates an example cleaning head 100 that includes a separable member 248 that does not include cleaning liquid applicator materials 126, 128. However, the cleaning liquid applicator materials 126, 128 remain separable, in which case each of the first and second applicator portions 126, 128 may be separated from the cleaning liquid outlet 104 independently of each other and independently of the separable member 248.

More generally, the present disclosure provides for the attachable (and/or detachable) member 248 itself. The attachable member 248 may be adapted to attach to a wet cleaning device having an under-pressure generator 178. In at least some embodiments, the attachable member 248 includes the porous material layer 114; and at least one dirty inlet 142A, 142B, the under-pressure generator 178 may be fluidly connected to the at least one dirty inlet 142A, 142B when the attachable member 248 is attached to the wet cleaning device, wherein the liquid pickup region PR of the porous material layer 114 is defined by a sealed attachment of the porous material layer 114 around the at least one dirty inlet 142A, 142B.

Such attachable members 248 enable replacement of the porous material layer 114 without the need to reseal the porous material layer 114 to the dirty inlet(s) 142A, 142B.

In some embodiments, the attachable member 248 includes the impermeable portion 146 and the at least one soil inlet 142A, 142B is defined by one or more apertures disposed in the impermeable portion 146 and/or between the impermeable portion 146 and the porous material layer 114. Such attachable members 248 may enable replacement of the porous material layer 114 without the need to reseal the impermeable portion 146 to the porous material layer 114.

In some embodiments, at least one of the dirty inlets 142A, 142B is exposed to the cavity 150 between the porous material layer 114 and the impermeable portion 146, the liquid transport support structure 154 is disposed in the cavity 150, and one or more flow paths are provided in the liquid pickup region PR between the porous material layer 114 and the at least one dirty inlet 142A, 142B.

A wet cleaning device, such as a cleaning head 100 included in a wet cleaning device, may include at least one cleaning liquid outlet 104 through which cleaning liquid may be delivered, as previously described. When the at least one dirty inlet of the attachable member 248 is fluidly connected to the under-pressure generator 178, the liquid pickup region PR may be arranged relative to each of the at least one cleaning liquid outlets 104 such that the liquid pickup region PR is bypassed by cleaning liquid delivered toward the surface 218 to be cleaned.

Fig. 29 schematically illustrates an example cleaning head 100 that includes a separable element 244, the separable element 244 in this example including one or more additional porous material layers 156. Further, in this non-limiting example, each of the first and second applicator portions 126, 128 may be separated from the cleaning liquid outlet 104 independently of each other and independently of the separable element 244 in this example.

Fig. 30 shows an exemplary cleaning head 100 in which the porous material (in this case porous material layer 114) contacts cleaning liquid applicator fabrics 126, 128. As previously explained, this configuration may help prevent excess cleaning liquid from accumulating in the cleaning liquid applicator materials 126, 128, and thus may help minimize excessive wetting of the surface 218 to be cleaned, for example, by dripping cleaning liquid from the cleaning liquid applicator materials 126, 128 onto the surface 218 to be cleaned.

In this particular example, because the edge portion 134 of the porous material layer 114 abuts the opposing edge portions 136 of the cleaning liquid applicator materials 126, 128, enhanced control of the humidity of the cleaning liquid applicator materials 126, 128 may be achieved.

More specifically, in this non-limiting example, the cleaning liquid applicator material 126, 128 includes a first applicator portion 126 and a second applicator portion 128 such that opposing edge portions 136 of the cleaning liquid applicator material are included in the first applicator portion 126, as shown. Further, in this example, another edge portion 138 of the porous material layer 114 abuts another opposing edge portion 140 of the second applicator portion 128.

However, in the example shown in fig. 30, the liquid pickup region PR of the porous material layer 114 (defined by the sealed attachment of the porous material layer 114 around, for example, each of the at least one dirty inlet 142A, 142B) is arranged relative to each of the cleaning liquid outlets 104, thereby allowing the cleaning liquid to bypass the liquid pickup region PR. In this regard, in this example, the cleaning liquid outlet 104 is arranged in a dispensing portion, in this example in the form of a cleaning liquid dispensing strip 108, 124, which is spatially separated from the porous material layer 114. The latter is reflected by a gap 242 (e.g. an air gap 242) provided between the porous material layer 114 and the distribution portion 108, 124.

Reiterating, the porous material 168 comprising the porous material layer 114 differs from the cleaning liquid applicator materials 126, 128 in that the porous material 168 is denser than the cleaning liquid applicator materials 126, 128, for example, due to the tighter weave of the microfiber fabric.

In some embodiments, as shown in FIG. 31, the cleaning head 100 includes a portion 120 facing the surface 218 to be cleaned, and the protruding element 252 is mounted adjacent to the portion 120. Thus, protruding element 252 is an element that is mounted separately from portion 120. Protruding elements 252 protrude from the cleaning head 100 in the direction of the surface 218 to be cleaned. In this manner, the cleaning head 100 can be swung in a first direction over the protruding element 252 to bring the portion 120 into contact with the surface to be cleaned and swung in a second direction opposite the first direction over the protruding element 252 to separate the portion 120 from the surface 218 to be cleaned, as previously described.

In some embodiments, as shown in fig. 31, the cleaning head 100 includes a support member 236, such as a rigid support member 236, and the protruding element 252 is mounted to the support member 236 by an attachment.

It should be noted that the cleaning head 100 can be attached or attachable to a suitable handle (not visible) to assist in moving the cleaning head 100. To this end, the cleaning head 100 may include a coupling 254, and such a handle may be coupled to the coupling 254, e.g., pivotably coupled.

Referring to fig. 31, the cleaning head 100 is cleaned by applying a force F _{Exercise machine} Movement over the surface 218 to be cleaned may not be free of resistance. Weight F of cleaning head 100 _{Gravity force} And/or a user pressing the cleaning head 100 toward the surface 218 to be cleaned may generate a force Fn perpendicular to the surface 218 to be cleaned.

The cleaning head 100 may be wet and thus may operate in a viscous friction state and a dry state; the former generates viscous friction Fv while the latter generates coulomb friction Fc, controlled by normal force Fn and friction coefficient f. The resulting resistance Fr is approximated in the following equation.

Wherein forces Fr, fv, fc and Fn are in newtons; mu is the dynamic viscosity in Pa.s; a is m is ² A measured contact area; u is the speed in m/s; and y is the liquid layer thickness in m.

The above equation shows that a liquid layer with a larger contact area a and thickness y towards zero can increase the viscous friction term and thus increase the resulting drag force Fr.

It should also be noted that the relatively large contact area a required to effectively pick up liquid on the uneven surface 218 to be cleaned may result in relatively high resistance Fr, particularly on the relatively flat/smooth surface 218 to be cleaned.

Thus, in at least some embodiments, the protruding element 252 includes a porous material 168. Because of the limited contact area a between the porous material 168 and the surface 218 to be cleaned, the resistance to movement of the cleaning head 100 over the surface to be cleaned can be reduced.

The porous material layer 114 of the porous material 168 may be included in the protruding elements 252.

In some embodiments, the liquid pickup region PR of the porous material layer 114 is included in the protruding element 252 and terminates between the protruding element 252 and the portion 120. In this way, the area of porous material layer 114 to which suction is applied is limited to protruding elements 252, thereby helping to mitigate resistance to movement.

Alternatively or additionally, at least one dirty inlet 142A, 142B may be defined in the protruding element 252. Thus, suction may be applied to the portion of the cleaning head 100 that is in contact with the surface 218 to be cleaned, in other words, to the protruding element 252, the contact of the protruding element 252 with the surface 218 to be cleaned being lessened, for example, due to its swinging function.

In embodiments where the cleaning head 100 includes a portion 120 and a further portion 122 facing the surface 218 to be cleaned, the protruding element 252 may be mounted between the portion 120 and the further portion 122. In this way, the cleaning head 100 can be swung forward over the projecting elements 252 so that the portion 120 contacts the surface 218 to be cleaned, as shown in fig. 31, and swung rearward so that the further portion 122 contacts the surface 218 to be cleaned.

In such embodiments, the liquid pickup region PR of the porous material layer 114 may extend between the portion 120 and the further portion 122 and terminate between the protruding element 252 and the portion 120, and between the protruding element 252 and the further portion 122.

In the non-limiting example shown in fig. 31, the adjacent opposing edge portions 134, 136 of the porous material 168 and cleaning liquid applicator materials 126, 128 are positioned between the protruding element 252 and the portion 120. In this manner, excess cleaning liquid squeezed from the cleaning liquid applicator material 126, 128 between the protruding element 252 and the cleaning liquid applicator material 126, 128, such as by oscillation of the cleaning head 100, may be effectively delivered into the dirty inlet(s) 142A, 142B via the porous material 168.

In particular, the portion 120 shown in fig. 31 includes a first applicator portion 126, and the further portion 122 includes a second applicator portion 128. Further, in this example, the contiguous opposing edge portions 134, 136 of the porous material 168 and the first applicator portion 126 are positioned between the protruding element 252 and the portion 120, and the contiguous opposing additional edge portions 138, 140 of the porous material 168 and the second applicator portion 128 are positioned between the protruding element 252 and the additional portion 122. Thus, excess cleaning liquid that is forced out of the cleaning liquid applicator material 126, 128 between the protruding element and the first applicator portion 126 and between the protruding element and the second applicator portion 128, for example, by swinging the cleaning head 100 forward and backward, respectively, may be effectively delivered into the dirty inlet(s) 142A, 142B via the porous material 168.

In some embodiments, as shown in fig. 31, the protruding element 252 has a curved surface arranged to contact the surface 218 to be cleaned.

Such a curved (e.g., rounded) surface of the protruding element 252 may further help to minimize the contact area of the protruding element 252 with the surface 218 to be cleaned, and thereby help to minimize the resistance to movement of the cleaning head 100 over the surface 218 to be cleaned.

The curved surface of protruding element 252 may be curved, for example, between portion 120 and further portion 122, as shown in fig. 31.

In some embodiments, protruding element 252 includes the aforementioned elastomeric material 238 with porous material 168 disposed thereon. The elastomeric material 238 may be or comprise, for example, silicone rubber and/or have a hardness of less than 50 shore a, preferably less than 20 shore a, most preferably less than 10 shore a.

Referring to fig. 31, an elastomeric material 238 may be disposed between the support member 236 (e.g., rigid support member 236) and the porous material 168.

Such elastic deformation of the elastomeric material 238 may reduce the risk of damaging the porous material 168 if, for example, relatively hard protrusions are present on the surface 218 to be cleaned in contact with the porous material 168. Alternatively or additionally, the elastomeric material 238 may help the porous material 168 follow any contour of the surface 218 to be cleaned.

Alternatively or additionally, protruding element 252 may be resiliently mounted adjacent portion 120. For example, the protruding element 252 may be spring mounted to the support member 236. This may help the porous material 168 follow any contours of the surface 218 to be cleaned, thereby facilitating liquid pick-up.

In embodiments in which the elastomeric material 238 is included in the protruding element 252, the curvature of the curved surface of the elastomeric material 238 (e.g., the arc between the portion 120 and the further portion 122) may be followed by the porous material 168 to provide the curved surface of the protruding element 252.

Although not visible in fig. 31, the protruding element 252 may further comprise the impermeable portion 146 described above, the impermeable portion 146 comprising or being in the form of a polymeric film sealed to the porous material layer 114 and surrounding the dirt inlets 142A, 142B. In such an example, the under-pressure that exists behind the porous material 168 during use of the cleaning head 100 may not exist in the elastomeric material 238, but rather is contained within the sealed cavity 150 between the porous material layer 114 and the impermeable portion 146. This may help ensure that the elastomeric material 238 is substantially unaffected by the under-pressure, particularly in examples where the elastomeric material 238 itself is porous and therefore may otherwise be prone to compaction due to the under-pressure.

In other non-limiting examples, the elastomeric material 238 itself is non-porous such that the elastomeric material 238 may be included in the impermeable portion 146 sealed to the porous material layer 114 of the porous material 168, for example as described above with respect to fig. 18.

In the non-limiting example shown in fig. 31, the liquid delivery support structure 154 described above is also disposed between the porous material 168, and in particular the porous material layer 114 and the impermeable portion 146. The liquid transport support structure 154 may be defined by or include, for example, one or more mesh layers and/or surface patterns on and/or in a surface, such as a curved surface, of the elastomeric material 238.

More generally, the protruding element 252 may include, for example, a liquid transport support structure 154 disposed between the porous material layer 114 and the at least one dirt inlet 142A, 142B.

The porous material 168 may be disposed on the elastomeric material 238 in any suitable manner, such as on a curved surface of the elastomeric material 238.

Fig. 32A and 32B schematically illustrate examples of sealingly attaching the porous material layer 114 around the dirt inlets 142A, 142B to define a liquid pick-up region PR. Further evident in fig. 32A and 32B are an impermeable portion 146 (in this case in the form of a polymeric film) and a liquid transport support structure 154 (in this case in the form of a mesh or a plurality of stacked mesh layers). The porous material 168 in this example includes or is defined by the porous material layer 114 and the additional porous material layers 156, 158. Thus, the laminate comprises further layers of porous material 156, 158, the layer of porous material 114, the liquid transport support structure 154 and the impermeable portion 146, wherein the tubes 144A, 144B providing the dirty inlets 142A, 142B are partially captured between the impermeable portion 146 and the layer of porous material 114.

In the non-limiting example shown in fig. 32A and 32B, the impermeable portion 146, the porous material layer 114 and the further porous material layers 156, 158 extend beyond the liquid transport support layer 154 in the direction of the tubes 144A, 144B. The seal 152, in this case a heat seal, also extends beyond the liquid transport support layer 154 in the direction of the tubes 144A, 144B.

By introducing clay in the area between the porous material layer 114 and the impermeable portion 146, a seal 152, i.e. a hermetic seal, is provided between the porous material layer 114 and the impermeable portion 146, the tubes 144A, 144B being guided to the impermeable portion 146. In this example, a piece of tape is then wrapped around the porous material layer 114, impermeable portion 146, tubes 144A, 144B, and clay to encapsulate the clay to avoid it sticking to another object.

The laminate may be flexible enough to be disposed on a curved surface, such as elastomeric material 238. Further, for example, the laminate may be provided with a suitable one or more fasteners 256A-D, in which case the fasteners 256A-D are VelcroIn the form of a strap for securing the laminate in the cleaning head 100.

Turning to the non-limiting example shown in fig. 33A and 33B, a laminate similar to that described above with respect to fig. 32A and 32B, including the porous material layer 114 and the additional first porous material layer 156, is disposed on the curved surface 258 of the elastomeric material 238 and secured thereto via fastener(s) 256A-D (e.g., velcro @) Is secured to the support member 236. Thus, the protruding element 252 in this example includes the elastomeric material 238 and the porous material layers 114, 156.

Since the porous material layers 114, 156 follow the curvature of the curved surface 258 of the elastomeric material 238 in this example, the protruding element 252 itself comprises a curved surface arranged to contact the surface 218 to be cleaned.

In the non-limiting example shown in fig. 33A and 33B, the protruding element 252 is mounted adjacent to the portion 120 (and in this example in particular between the portion 120 and the further portion 122) by an elastomeric material 238 attached to the support member 236 of the cleaning head 100. In this non-limiting example, the attachment is at least partially achieved by the elastomeric material 238, the elastomeric material 238 including a protrusion 260, the protrusion 260 being received within a slot 262 defined in the support member 236 and engaged with the slot 262. The projection 260 may be, for example, a push fit in the slot 262.

Fig. 33A illustrates a deformation of the cleaning liquid applicator materials 126, 128 to bring at least a portion of the cleaning liquid applicator materials 126, 128 into contact with the porous material. In this way, some cleaning liquid may be transferred from the cleaning liquid applicator materials 126, 128 to the porous material in a particularly controlled manner.

In the non-limiting example shown in fig. 33A, the cleaning liquid applicator materials 126, 128 include tufts formed from fibers and a backing layer (not visible) that supports the tufts. As shown, such tufts can deform to contact the porous material, for example, upon contact with a surface to be cleaned and/or upon wetting by a liquid such as water.

In some embodiments, the wet cleaning apparatus includes a cleaning head 100 and an under-pressure generator 178 (not visible in fig. 33A and 33B) fluidly connected to at least one of the dirty inlets 142A, 142B. This fluid connection may be achieved by the tubes 144A, 144B, in this particular non-limiting example, the tubes 144A, 144B extending to a single tube leading to the under-pressure generator at bifurcation 266.

The under-pressure generator 178 may be or include, for example, a pump, such as a positive displacement pump (the technical advantages of which are described in more detail below). Any suitable pump may be used as long as the pump is capable of withstanding the operating pressure selected for the wet cleaning apparatus, for example about 5000Pa (see Table 1 above).

In some embodiments, the under-voltage generator 178 is configured to generate a voltage by providing 15cm ³ Per minute to 2000cm ³ Per minute, preferably 40cm ³ Per minute to 2000cm ³ Per minute, more preferably 80cm ³ Per minute to 750cm ³ Per minute, most preferably 100cm ³ Per minute to 300cm ³ Flow in the range of/min to provide suction.

Such flow, i.e., flow rate, may take advantage of the under-pressure retention capability of the porous material 168 and may ensure adequate liquid pickup while limiting energy consumption.

The wet cleaning apparatus may also include a dirty liquid collection tank (not visible in fig. 33A and 33B). In such an embodiment, the under-pressure generator may be arranged to draw liquid from the at least one dirty inlet 142A, 142B to the dirty liquid tank.

In such embodiments, the dirty liquid collection tank may be arranged in any suitable manner with respect to the under-pressure generator 178, such as upstream or downstream of the under-pressure generator 178.

In some embodiments, a wet cleaning device comprising a cleaning head 100 comprises a cleaning liquid supply (not visible in fig. 33A and 33B) for supplying cleaning liquid to the cleaning head 100 for delivery through at least one cleaning liquid outlet 104 towards a surface to be cleaned. Such a cleaning liquid supply may for example comprise a cleaning liquid reservoir and a delivery device, for example a delivery device comprising a pump, for delivering the cleaning liquid to and through the at least one cleaning liquid outlet 104.

The cleaning liquid supply and the at least one cleaning liquid outlet 104 may be configured to provide continuous delivery of the cleaning liquid towards the surface 218 to be cleaned.

The cleaning liquid supply and under-pressure generator 178 may, for example, be configured such that the flow rate of the cleaning liquid delivered through the at least one cleaning liquid outlet 104 is lower than the flow rate provided by the under-pressure generator 178 to the at least one dirty inlet 142A, 142B. This helps to ensure that the surface 218 to be cleaned is not excessively wetted by the cleaning liquid. For example, the flow rate of the cleaning liquid may be 20cm ³ Per minute to 60cm ³ In the range of/min, the flow provided by the under-pressure generator 178 may be 40cm ³ Per minute to 2000cm ³ In the range of/min, more preferably 80cm ³ Per minute to 750cm ³ In the range of/min, most preferably 100cm ³ Per minute to 300cm ³ In the range of/min.

If a positive displacement pump is used as the under-pressure generator 178, such a pump may become relatively bulky and noisy at a flow rate of 1 liter/min or 2 liters/min, and thus a lower flow rate may help keep the wet cleaning apparatus relatively small, quiet and lightweight.

In principle, it is sufficient that the flow rate of the under-pressure generator 178 is equal to the flow rate of the cleaning liquid provided by the cleaning liquid supply.

However, if, for example, the porous material 168 (e.g., newly attached) encounters an overflow of water, this may risk relatively significant disturbance (necessarily under-pressure) to the system balance. For example, by having a length of 40cm ³ Cleaning liquid flow rate per minute and 50cm provided by under-pressure generator 178 ³ 50cm encountered by wet cleaning apparatus with flow rate per minute ³ Puddles may mean that about 5 minutes are required to draw in all the water (resulting in a 5 minute undervoltage drop, so the floor remains significantly more wet for a 5 minute period (because puddles remain open)). On the other hand, 250cm provided by the under-voltage generator 178 ³ The flow rate per minute may reduce it to a period of 14 seconds. The higher flow rate provided by the under-pressure generator 178 than the flow rate of the cleaning liquid provided by the cleaning liquid supply may allow the system to return to equilibrium more quickly after such a disturbance.

In the non-limiting example shown in fig. 33A and 33B, cleaning liquid is delivered, for example, from the above-described cleaning liquid reservoir via a tube 268, which tube 268 diverges to supply cleaning liquid to the cleaning liquid outlet 104 of the cleaning liquid distribution strip 108 via a first tube 270A and to the cleaning liquid outlet 104 of the further cleaning liquid distribution strip 124 via a second tube 270B.

In embodiments where the wet cleaning apparatus comprises a cleaning head 100, an under-pressure generator and a cleaning liquid supply, the under-pressure generator may be configured to provide suction to the at least one dirty inlet 142A, 142B while the cleaning liquid supply supplies cleaning liquid to the at least one cleaning liquid outlet 104 and through the at least one cleaning liquid outlet 104 (in other words, simultaneously).

In the exemplary cleaning head 100 shown in fig. 33A and 33B, the cleaning liquid distribution strips 108, 124 are engaged with each other and the support member 236 by the engagement members 272A, 272B.

In some embodiments, the wet cleaning device includes a handle (not visible in fig. 33A and 33B) coupled or attachable to the cleaning head 100. Such a handle may facilitate movement of the cleaning head 100.

In the non-limiting example shown in fig. 33A and 33B, the coupling point 254 to which such a handle may be coupled includes a vertically extending slot for adjusting the height that provides the coupling. In this example, such a coupling point 254 is provided in each of a pair of mounts 274A, 274B, with a handle engagement member 276 pivotally mounted between the mounts 274A, 274B. The handle engagement member 276 may be engaged with, e.g., receive, an end of the handle.

In some embodiments, the handle may support or include at least a portion of an under-pressure generator 178 fluidly connected to the at least one dirty inlet 142A, 142B and/or the dirty liquid collection tank. Alternatively or additionally, at least a portion of the cleaning liquid supply, such as the cleaning liquid reservoir and/or the delivery device, may be supported by or included in the handle.

In some embodiments, as shown in fig. 33C and 33D, the attachable member 248 described above (wherein the liquid pickup region PR of the porous material layer 114 is defined by the sealed attachment of the porous material layer 114 around the at least one dirty inlet 142A, 142B) includes (or defines) a protruding element 252.

In the non-limiting example shown in fig. 33C, the protruding element 252 includes an elastomeric material 238 having a porous material layer 114 disposed thereon. In this particular example, the porous material layer 114 is sealingly attached to the support member 236 via a seal 152 (e.g., a heat seal).

In this manner, the porous material layer 114 is sealingly attached to the dirty inlet(s) 142A, in this example, the dirty inlet 142A is defined in the support member 236 and the elastomeric material 238, i.e., defined by the support member 236 and the elastomeric material 238. In this particular example, the dirt inlets 142A, 142B are in the form of channels extending through the support member 236 and the elastomeric material 238.

More generally, the support member 236 to which the porous material layer 114 is sealingly attached may be included in the attachable member 248. In such an example, the support member 236 may be attached to a support included in (the remainder of) the cleaning head 100.

The attachable member 248 may be attached to the support in any suitable manner, such as by an attachable member 248, such as the support element 236, having a ridge member that is push-fit into a slot defined in the support, or by a support having such a ridge member that is push-fit into a slot defined in the attachable member 248, such as the support element 236.

In the example shown in fig. 33C, an additional layer of porous material 156 is also included in the protruding element 252. It should be noted that the process of heat sealing the porous material layer 114 to the plastic support member 236, such as via ultrasonic welding, also causes the additional porous material layer 156 to become adhered to the porous material layer 114.

The examples shown in fig. 33C and 33D differ from each other in that the liquid delivery support structure 154 shown in fig. 33C is defined by a surface pattern disposed on and/or in the surface of the elastomeric material 238, while the liquid delivery support structure 154 shown in fig. 33D is in the form of a mesh layer.

Fig. 33E illustrates an exemplary detachable element 244 that includes additional layers of porous material 158A, 158B and cleaning liquid applicator material 126, 128. This example has some similarities to the detachable element 244 shown in fig. 26, except that in this case the cleaning liquid applicator materials 126, 128 are mounted on the additional porous material layers 158A, 158B.

It should be noted that the additional porous material layers 158A, 158B may be adhered to each other, for example, via heat sealing (e.g., ultrasonic welding).

Further evident in fig. 33E is the backing layer BL and tufts TU included in the cleaning liquid applicator materials 126, 128. As previously described, backing layer BL supports tufts TU.

Figure 33F provides a perspective view of the cleaning head 100 including the protruding element 252/attachable member 248 shown in figure 33C or figure 33D and the detachable element 244 shown in figure 33E. Thus, in this case, the porous material 168 includes the porous material layer 114 and the further porous material layer 156 included in the protruding element 252/attachable member 248, as well as the further porous material layer(s) 158A, 158B included in the detachable element 244.

The separable element 244 can be detachably coupled to the cleaning head in any suitable manner100, for example by means of a separable element 244, the separable element 244 comprising a set of shoes arranged along one longitudinal side of the separable element 244 and velcro arranged on the opposite longitudinal sideA belt. In this example, each of a set of shoes receives and engages a foot provided on one longitudinal side of the rest of the cleaning head 100, and Velcro +.>The strap can be joined to complementary Velcro arranged on opposite longitudinal sides of the rest of the cleaning head 100>A belt. The set of foot-set shoe arrangements can help minimize unwanted movement of the separable element 244 in the lateral and longitudinal directions relative to the remainder of the cleaning head 100.

Further evident in fig. 33F is the tag LA of the detachable element 244. The label may provide instructions for attachment/detachment and/or cleaning of the detachable element 244 after the detachable element 244 is detached from the remainder of the cleaning head 100.

More generally, a wet cleaning device according to one aspect of the present disclosure includes an under-pressure generator device and a cleaning head 100, the cleaning head 100 having at least one dirty inlet 142A, 142B and a porous material 168, the porous material 168 including a porous material layer 114 sealingly attached to the at least one dirty inlet 142A, 142B.

The cleaning head 100 may be, for example, in accordance with any of the embodiments described herein.

The under-voltage generator device includes an under-voltage generator 178 having an under-voltage generator outlet, the under-voltage generator 178 being activatable to provide flow from the at least one dirty inlet 242A, 242B to and through the under-voltage generator outlet, and being deactivatable to stop flow.

In at least some embodiments, the under-voltage generator device is configured to limit a passage of fluid from the under-voltage generator outlet toward the at least one dirty inlet 242A, 242B at least when the under-voltage generator is deactivated.

The flow provided by the under-pressure generator 178 may create an under-pressure in the at least one dirty inlet 142A, 142B. The porous material 168, and in particular the wetted porous material 168, may help to maintain the under-pressure, and liquid may be drawn through the porous material 168 and into the dirty inlet(s), as previously described.

Fig. 34 schematically illustrates an exemplary wet cleaning device 278 before (left-hand square), during (center square) and after (right-hand square) drawing a liquid 190 through the porous material 168. The left hand square of fig. 34 can be seen as depicting a completely dry system, for example, at the beginning of a cleaning cycle. The central pane of fig. 34 shows the wet cleaning device 278 in operation during which liquid 190 (e.g., water) in contact with the porous material 168 is conveyed through the wet cleaning device 278 in the direction of the dirty inlet(s) 142A. Thus, the surface 218 to be cleaned may be dried or at least drier, but not all of the liquid 190 may be transported away from the cleaning head 100, for example to a dirty liquid collection tank (not visible in fig. 34) included in the wet cleaning apparatus 278. In this non-limiting example, some liquid 190 may remain in the flow path(s) of the liquid transport support structure 154, as shown. During operation, this liquid 190 may be beneficial because it serves to keep the porous material 168 wet even when no liquid 190 is present on the surface 218 to be cleaned. As previously discussed, the residual liquid 190 in the pores 192 of the porous material 168 helps to maintain the under-pressure. While maintaining an under-pressure in the dirty inlet(s) 142A, the liquid 190 remains on the dirty inlet side(s) of the porous material 168, as shown in the central square of fig. 34.

However, when the under-pressure generator 178 is deactivated, such as by being turned off after use of the wet cleaning device 278, loss of the under-pressure may be caused by fluid (e.g., ambient air) entering through the under-pressure generator outlet. This may result in the release, e.g., dripping, of the liquid 190 from the porous material 168, as shown in the right-hand square of fig. 34.

After cleaning, such as wiping the surface to be cleaned, it is undesirable for the liquid 190 to be released through the porous material 168 when the under-pressure generator 178 is deactivated, such as back onto the surface 218 to be cleaned (or cleaned) and/or during transport of the wet cleaning device 278 to its storage location.

To this end, the under-voltage generator device may be configured to restrict (e.g., block) the passage of fluid (e.g., ambient air) from the under-voltage generator outlet toward the dirty inlet(s) at least when the under-voltage generator 178 is deactivated, e.g., when the under-voltage generator 178 is shut off. This may mitigate the release of problematic liquids from the porous material 168, for example, after cleaning the surface 218 to be cleaned and/or during loading of the wet cleaning device in a storage area after use.

Fig. 35 schematically illustrates an example wet cleaning device 278 including such an under-voltage generator device 280. In the left hand square of fig. 35, the under-pressure generator 178, in this example a pump, is activated. This is denoted "pump on". In the right hand square of fig. 35, the under-pressure generator 178 is deactivated, denoted "pump off". In contrast to the liquid leakage described above with respect to fig. 34, the passage of fluid from the under-pressure generator outlet toward the dirty inlet(s) 142A is restricted, e.g., blocked, as shown by the cross 282 in fig. 35. In this way, the under-pressure may be better maintained after the under-pressure generator 178 is deactivated, thereby mitigating problematic release of liquid from the porous material 168.

Any suitable manner of configuring the under-voltage generator device 280 to restrict the passage of fluid from the under-voltage generator outlet toward the dirty inlet(s) 142A, at least when the under-voltage generator 178 is deactivated, is contemplated.

In some embodiments, the under-voltage generator 178 itself is configured to limit backflow of fluid, such as air, from the under-voltage generator outlet in the direction of the dirty inlet(s) 142A when the under-voltage generator 178 is deactivated.

In some embodiments, as shown in FIG. 36, the under-pressure generator 178 is or includes a positive displacement pump. The design of such a positive displacement pump means that backflow of fluid (e.g., air) from the under-pressure generator outlet (in other words, the pump outlet) in the direction of the dirty inlet(s) 142A is inherently limited.

Examples of such positive displacement pumps include peristaltic pumps, diaphragm pumps, and piston pumps. Thus, the under-pressure generator 178 may include or consist of one or more of a peristaltic pump, a diaphragm pump, and a piston pump.

Referring to fig. 36, the peristaltic pump depicted may include a compressible hose 284 between a pump/under-pressure generator inlet 286 and a pump/under-pressure generator outlet 288, the compressible hose 284 being compressed in at least one position when the peristaltic pump is deactivated. Thus, when the peristaltic pump is deactivated, backflow of fluid, such as air, from the pump outlet toward the dirty inlet(s) 142A may be limited, such as blocked. Accordingly, the peristaltic pump selection may minimize under-pressure losses in the dirty inlet(s), thereby minimizing problematic liquid release outside the cleaning head 100 through the porous material 168.

The peristaltic pump may, for example, include a rotatable compression shoe assembly 290, the compression shoe assembly 290 including at least one compression shoe 292, rotation of the compression shoe assembly 290 and concomitant compression of the compressible hose 284 by the at least one compression shoe 292 providing flow.

The diaphragm pump and piston pump described above use a similar type of configuration in which the rest state of the pump, i.e. when the pump is deactivated, restricts back flow from the pump outlet 288 in the direction of the dirty inlet(s) 142A.

In some embodiments, for example, as an alternative or in addition to the positive displacement pump described above that constitutes the under-pressure generator 178, the under-pressure generator device 280 includes a valve assembly, for example, represented by a cross 282 in fig. 35, configured to restrict the passage of fluid from the under-pressure generator outlet 288 toward the at least one dirty inlet 142A.

In the non-limiting example shown in fig. 35, the valve assembly is configured to restrict the passage of fluid between the under-pressure generator inlet 286 and the at least one dirty inlet 142A.

Alternatively or additionally, a passage of fluid may be restricted between the under-pressure generator outlet 288 and the under-pressure generator inlet 186, e.g., as described above with respect to the positive displacement pump included in the under-pressure generator 178 or defining the under-pressure generator 178.

The valve assembly may be of any suitable design. In some embodiments, the valve assembly is configured to restrict the passage of air in response to the under-pressure generator 178 being deactivated. This may be considered an "active" valve that is triggered by the undervoltage generator 178 being deactivated to shut down the system (by restricting the passage of fluid from the undervoltage generator outlet 288 toward the dirty inlet(s) 142A).

In some embodiments, the valve assembly includes a one-way valve configured to prevent fluid from being delivered in the direction of the at least one dirty inlet 142A. The one-way valve may be considered a "passive" valve. Such a one-way valve may be provided to allow a flow of fluid, such as air and/or liquid, to leave the porous material 168, but prevent the fluid (e.g., air and/or liquid) from returning toward the dirty inlet(s) 142A when and after the under-pressure generator 178 is deactivated. Any suitable one-way valve design is contemplated, such as a ball check valve.

In a non-limiting example, an additional porous material portion, for example made of microfiber fabric, is disposed between the porous material layer 114 and the under-pressure generator outlet 288. The additional porous material portion can allow fluid flow (e.g., air and/or liquid) to leave the porous material layer 114, but at least restrict fluid (e.g., air and/or liquid) from returning toward the porous material layer 114 when the under-pressure generator 178 is deactivated.

More generally, the under-voltage generator 178 may be configured such that when flow is provided by the (activated) under-voltage generator 178, the flow is at 40cm ³ Per minute to 2000cm ³ In the range of/min, more preferably 80cm ³ Per minute to 750cm ³ In the range of/min, most preferably 100cm ³ Per minute to 300cm ³ In the range of/min.

To reiterate, the wet cleaning device 278 may include a dirty liquid collection tank (not visible in fig. 35 and 36) for collecting dirty liquid, and the under-pressure generator device 280 is arranged such that flow to and through the under-pressure generator outlet 288 draws dirty liquid from the at least one dirty inlet 142A to the dirty liquid collection tank. In such embodiments, the valve assembly described above may be arranged in any suitable manner, for example, upstream or downstream with respect to the dirty liquid collection tank.

In some embodiments, a sealed flow path is defined between the dirty inlet(s) 142A and the under-pressure generator outlet 288.

This helps to maintain the under-voltage.

In alternative embodiments, a fluid (e.g., air) may enter via one or more regions of the wet cleaning device 278 other than the under-pressure generator outlets 288 and the pores 192 of the porous material 168.

However, in such an alternative embodiment, the configuration of the under-pressure generator device 280 may still help to maintain the under-pressure by (at least) restricting the passage of fluid from the under-pressure generator outlet 288 in the direction of the dirty inlet 142A.

In some embodiments, the under-pressure generator device 280 includes a valve assembly 282, such as the valve assembly 282 described above, positioned between the one or more regions and the dirty inlet(s) 142A, thereby limiting backflow from the one or more regions toward the dirty inlet(s) 142A. In such an embodiment, the valve assembly 142A may, for example, limit backflow from one or more regions in addition to restricting the passage of fluid from the under-pressure generator outlet 288 in the direction of the dirty inlet(s) 142A.

More generally, a wet cleaning device according to another aspect of the present disclosure includes an under-pressure generator device 280 and a cleaning head 100, the cleaning head 100 having at least one dirty inlet 142A, 142B and a porous material 168 covering the at least one dirty inlet 142A, 142B. In some embodiments, the porous material 168 includes a porous material layer 114 sealingly attached to at least one of the dirty inlets 142A, 142B. The cleaning head 100 may be, for example, in accordance with any of the embodiments described herein. In this aspect, the under-pressure generator device 280 includes an under-pressure generator 178, the under-pressure generator 178 configured to provide a flow inside the wet cleaning device for drawing fluid through the porous material 168 into the at least one dirty inlet, the under-pressure generator device 280 configured to control the flow based on a pressure between the porous material 168 and the under-pressure generator 178, for example on an inner side of the wet cleaning device in the at least one covered dirty inlet 142A, 142B.

By controlling the flow by the under-pressure generator device 280 based on the pressure on the inside of the wet cleaning device between the porous material 168 and the under-pressure generator 178, the fluid delivery through the porous material 168 may be advantageously controlled. In some non-limiting examples, such control may minimize foam accumulation in the porous material 168 and downstream of the porous material 168.

In some embodiments, the under-pressure generator device 280 is configured to control the flow such that the pressure remains at or above a predetermined pressure threshold.

By controlling the flow to maintain the pressure at or above a predetermined threshold (in other words, at or below an under-pressure threshold), stable and efficient operation of the wet cleaning device 278 may be facilitated. In particular, maintaining the pressure at or above the predetermined threshold may mean that the under-pressure generator 178 may operate more efficiently, such as by intermittently disabling/switching off, thereby taking advantage of the above-described capabilities of the porous material 168 to help maintain the under-pressure in the covered dirty inlet(s) 142A, 142B.

As previously mentioned, control of the flow rate may also help control the humidity of the surface to be cleaned.

Fig. 37A schematically illustrates pores 192, such as micropores 192, of the porous material layer 168 filled with a liquid 190, such as water. The retained liquid 190 may thus help to maintain an under-pressure in the dirty inlet(s) 142A, with or without the flow applied by the under-pressure generator 178, as previously described.

As also previously explained, each of the pores 192 of the porous material 168 may have a burst pressure at which the surface tension of the (residual) liquid 190 residing in the pores 192 is no longer subject to internal under-pressure and is allowed to pass. When this occurs, the aperture 192 is no longer effectively closed by the liquid contained therein, but rather air may begin to be delivered into the dirty inlet(s) 142A.

A typical pump used as the under-pressure generator 178 may be, for example, a flow-driven pump or a positive displacement pump, such as a piston pump, and may be moved toward its maximum operating pressure, such as 20000Pa, when the porous material 168 is plugged. The latter may be above the average burst pressure of the porous material 168, for example about 5000Pa, so that the porous material 168 may begin at a point to allow air to pass therethrough.

The use of pure water, for example, as the liquid 190 may cause little, if any, difficulty. However, problems may occur when foaming cleaning agents are included in the cleaning liquid 190. Referring to fig. 37B, the ruptured holes 294 may begin delivering air at the rate of the under-pressure generator 178 (e.g., a pump), which may risk generating a relatively large amount of foam 296, which foam 296 may, for example, relatively quickly flood a dirty liquid collection tank (not visible in fig. 37B).

In a specific non-limiting example, the pump of the cleaning liquid supply described above (not visible in FIG. 37B) delivers 40cm ³ A flow of cleaning liquid per minute. Thus, it may be only 40cm ³ For example water, can be used for pick-up. In this example, the under-pressure generator 178 (e.g., pump) delivers approximately 150cm ³ Flow per min. The combination can produce a composition of at least (150 cm ³ Per minute-40 cm ³ 110 cm/min =) ³ Foam per minute. For example, when 400cm ³ When a volumetric dirty liquid collection tank is included in the wet cleaning apparatus 278, this may reach capacity (at 40cm in about 4 minutes ³ Pick-up rate per minute reaches capacity in about 10 minutes).

This means that if no remedial action is taken, particularly when aqueous cleaning agents are included in the cleaning liquid, rapid foam build-up can cause disruption in the use of the wet cleaning device 278. Such interruptions may include frequent interruptions of cleaning to empty the dirty liquid collection tank.

Thus, the predetermined pressure threshold may be set, for example, to avoid reaching a burst pressure of at least some of the pores 192 (e.g., most or all of the pores) of the porous material 168. This helps to avoid operational problems associated with foam when using a cleaning agent.

The pressure threshold may be set/predetermined based on the burst pressure of the porous material 168 (as measured using the test device 166 and test procedure described above). Thus, the predetermined pressure threshold may be set to a value that limits the underpressure, in other words, the pressure difference between the inside of the wet cleaning device between the porous material and the underpressure generator and the outside of the cleaning head 100, e.g. the atmospheric pressure, to (e.g. at most) 2000Pa to 13500Pa, preferably 2000Pa to 13500Pa, more preferably 5000Pa to 9000Pa, most preferably 7000Pa to 9000 Pa.

Studies have shown that the higher the under-pressure, the drier the surface to be cleaned may become, as explained before (see table 1 above). This concludes as follows: the wet cleaning device 278 desirably operates at the burst pressure of the porous material 168.

The above studies indicate that operating at an under pressure of 5000Pa can provide advantageous surface drying results. Thus, a working window capable of preventing foaming can be defined. Table 3 provides specific non-limiting examples of the operating parameters of exemplary wet cleaning device 278.

Cleaning liquid supply pump flow	40cm ³ Per minute
		Flow delivered by an under-pressure generator 178 (e.g., pump)	150cm ³ Per minute
Fracture pressure of porous material 168	6500Pa
		Operation ofPressure of	5000Pa

TABLE 3 Table 3

The above parameters may reflect that the porous material 168 may exhibit advantageous surface drying capacity at 5000Pa, and may start "cracking" only at 6500 Pa.

Thus, by adjusting the pressure, in other words selecting the above-described pressure threshold, such that the under-pressure behind porous material 168 does not reach the cracking pressure of porous material 168, foaming may be minimized or prevented.

Fig. 37C illustrates an operating window of the wet cleaning device, particularly when the wet cleaning device is started. Fig. 37C shows the pressure versus time relative to atmospheric pressure.

The burst pressure BP of the porous material 168 may be considered negative (with reference to atmospheric pressure). Accordingly, the pressure of the inside of the wet cleaning device between the porous material 168 and the under-pressure generator 178 may be maintained above the under-pressure BP. On the other hand, if the burst pressure of the porous material is an absolute pressure (see vacuum, 0 Pa), the pressure of the inside of the wet cleaning device between the porous material 168 and the under-pressure generator 178 may still be maintained above such absolute pressure, particularly by the flow being controlled so as to maintain the pressure at or above a predetermined threshold PT.

Fig. 37C also shows a "safe zone" SZ at or above a predetermined threshold PT at which the wet cleaning device may be operated without approaching the burst pressure BP of the porous material 168. Furthermore, fig. 37C shows an optimal working zone OZ where the need to avoid reaching the burst pressure BP of the porous material 168 is combined with the realization of a sufficient liquid pick-up from the surface to be cleaned.

More generally, controlling flow based on pressure in the at least one covered fouling inlet 142A may be accomplished in any suitable manner. In some embodiments, such as the embodiment shown in fig. 38, the under-pressure generator device 280 includes a sensor 180 and a controller 298, the sensor 180 being arranged to sense a measurement of the pressure of the wet cleaning device on the inside between the porous material 168 and the under-pressure generator 178, the controller 298 being configured to control the under-pressure generator 178 to provide a flow rate based on the sensed pressure measurement.

The controller 298, such as a microcontroller, may receive the sensor signal from the sensor 180, as indicated by arrow 300 in FIG. 38, and send a control signal 302 to the under-voltage generator 178 based on the sensor signal.

For example, the control signal 302 may trigger the under-voltage generator 178 to activate to provide flow or deactivate to stop flow. Alternatively or additionally, the control signal 302 may increase or decrease the flow rate in accordance with the sensor signal 300. Disabling or reducing the flow provided by the under-voltage generator 178 in this manner may help reduce the power consumption of the wet cleaning device 278. This may help to maintain battery power in examples where the wet cleaning device is battery-powered/battery-powered, and thereby increase run time.

In some embodiments, the controller 298 is configured to control the flow provided by the under-pressure generator 178 such that the pressure on the inside of the wet cleaning device between the porous material 168 and the under-pressure generator 178 is maintained at or above the predetermined pressure threshold described above. In a non-limiting example, if the sensed pressure measurement indicates that the pressure is below a predetermined pressure threshold, the under-pressure generator 178 may control the under-pressure generator 178 to deactivate to stop or reduce the flow.

In a non-limiting example, the controller 298 (e.g., including or in the form of a proportional-integral controller) is configured to compare the sensed measurement of pressure to a desired operating pressure (e.g., as described above with reference to the burst pressure setting of the porous material 168) and to control the under-pressure generator 178 based on the comparison.

In some embodiments, the sensor 180 is arranged to sense a measure of pressure in at least one of: a cavity 150 between the porous material 168 and the at least one dirty inlet 142A, and a tube 144A (or a plurality of tubes 144A,144 b) connecting the at least one dirty inlet 142A with the under-pressure generator 178.

The pressure measurement in the sensing cavity 150 may be particularly advantageous because the flow may be more directly tuned to the characteristics of the porous material 168 during use.

Arranging the sensor 180 such that the pressure measurements sensed in the tube(s) 144A,144B may provide a relatively straightforward way to incorporate the sensor 180 into a wet cleaning device.

In embodiments where the under-pressure generator 178 is disposed downstream of the dirty liquid tank, the sensor 180 may also be positioned in the dirty liquid tank. In this case, for example, the height of the dirty liquid collection tank arranged on or in the handle may generate noise (dp=h×cos (α) ×ρ×g), where H is the height of the dirty liquid collection tank in the vertical position and α is the angle of the handle relative to the vertical direction. However, this noise may be compensated for by including an angle sensor (e.g., an accelerometer) in the sensor 180.

More generally, the sensor 180 may be any suitable type of sensor that is capable of sensing a measurement of the pressure on the inside of the wet cleaning device between the porous material 168 and the under-pressure generator 178. For example, the sensor includes a pressure sensor, such as a microelectromechanical (MEMS) pressure sensor.

In some embodiments, such as the embodiment shown in fig. 39, the under-pressure generator device 280 includes a mechanical regulator 304, the mechanical regulator 304 configured to control flow based on pressure on an inner side of the wet cleaning device between the porous material 168 and the under-pressure generator 178.

The mechanical regulator 304 may, for example, comprise valves 306, 308, the valves 306, 308 being arranged to control fluid communication between the under-pressure generator 178 and the at least one dirty inlet 142A in dependence of the pressure in the at least one covered dirty inlet 142A.

In the non-limiting example shown in fig. 39, the valve 306, 308 includes a valve seat 306 and a valve member 308, the valve member 308 being configured to assume an initial position in which the valve member 308 is separated from the valve seat 306 to allow fluid communication between the under-pressure generator 178 and the at least one dirty inlet 142A, and a closed position in which the valve member 308 abuts the valve seat 306 to limit fluid communication between the under-pressure generator 178 and the at least one dirty inlet 142A.

In some embodiments, the valves 306, 308 are configured such that when the pressure is below the predetermined pressure threshold described above, the valve member 308 is caused to move against the valve seat 306 by the pressure in the at least one covered dirty inlet 142A.

The valve member 308 may be, for example, in the form of a flexible rubber membrane that adopts a flat profile at the initial position and is thus spatially removed from the valve seat 306 when there is no under-pressure in the covered dirt inlet(s) 142A. After the under-pressure generator 178 (e.g., a pump) is activated, an under-pressure may be generated in the covered dirty inlet(s) 142A and the mechanical regulator 304. The under-pressure may act on the exposed surface of the rubber membrane in the mechanical regulator 304, which may thus begin to deflect inward in the direction of the valve seat 306.

In this non-limiting example, the threshold pressure may be set/predetermined by the distance between the flexible rubber membrane and the valve seat 306. The greater the distance, the higher the under-pressure (or equivalently, the lower the pressure) in the covered dirt inlet(s) 142A required to deform the rubber membrane to contact the valve seat 306.

Once the under-pressure reaches a level where the rubber membrane contacts the valve seat, fluid communication between the under-pressure generator 178 and the porous material 168 may be removed, thereby preventing the under-pressure from reaching a level higher than that set by the mechanical regulator 304. The brown-out generator 178 may maintain the brown-out operation at the same rate toward its maximum operation. When the under-pressure in the covered dirt inlet(s) 142A decreases, the flexible membrane may move back toward the flat state described above, opening the valves 306, 308 and allowing the under-pressure generator 178 to resume the desired under-pressure level.

In another non-limiting example, the mechanical regulator 304 includes a switch, actuation of which controls the under-voltage generator 178, and a deflectable member, such as a diaphragm, configured to actuate the switch in response to pressure.

Such a mechanical regulator, in this case an electromechanical regulator, may be configured such that when, for example, the pressure is at or above a predetermined pressure threshold, a switch is actuated by the diaphragm, for example, to deactivate the under-pressure generator 178.

Such a switch-diaphragm device may provide a simple and inexpensive way to control flow based on pressure without the need for an additional controller, such as a microcontroller.

In some embodiments, as shown in fig. 40 and 41, the under-pressure generator 178 itself includes a pump configured to control flow in response to pressure in the at least one covered fouling inlet 142A.

Such a pump may be considered a pressure limiting pump. The pressure limiting pump is capable of creating a certain pressure difference over the pipe to which it is connected. In principle, the pump pressure may be tuned to the pressure required to cover the porous material 168 of the dirt inlet(s) 142A.

The pressure limiting pump may comprise or be, for example, a centrifugal pump. The pump, for example a centrifugal pump, may be or comprise a liquid pump. Such a liquid pump may be arranged, for example, between the dirty inlet 142A and the dirty liquid tank 310.

In the non-limiting example shown in fig. 40, an under-pressure generator 178, such as a centrifugal pump and/or a liquid pump, is disposed in the cleaning head 100.

Alternatively, the pump, for example a centrifugal pump, may be or comprise an air pump. Such an air pump may be arranged downstream of the dirty liquid tank 310, for example.

It should be noted that the dirty liquid collection tank 310 may be arranged at a certain height 312 on the handle, for example 0.5m. Additional head may be required:

P＝h*ρ*g＝0.5*1000*9.81～5000Pa

when considering the position of the handle, including where the handle is lying on a horizontal surface 218 to be cleaned, such as a floor surface (where the head of water becomes zero), the pressure change across the porous material 168 may be equal to its operating pressure. The latter may be addressed by attaching the tube 144A at a fixed height relative to the floor, regardless of the position of the handle, for example by directly attaching (a portion of) the dirty liquid collection tank 310 to the porous material 168.

Fig. 41 schematically illustrates a wet cleaning device 278 in which an under-pressure generator 178 is used to regulate pressure using a pressure-limiting air pump (e.g., a centrifugal air pump). This may provide a start-up benefit over the example shown in fig. 40, as the pump may always be operated with air, thereby ensuring that the pump is able to produce the required under-pressure (porous material 168 is completely dry) at start-up.

In some embodiments, the under-voltage generator 178, regardless of its design, is configured such that when a flow rate is provided, the flow rate is at 40cm ³ Per minute to 2000cm ³ In the range of/min, more preferably 80cm ³ Per minute to 750cm ³ In the range of/min, most preferably 100cm ³ Per minute to 300cm ³ In the range of/min.

Such a flow, i.e. flow rate, may take advantage of the under-pressure retention capability of the porous material and may ensure adequate liquid pick-up while limiting energy consumption, as previously described.

More generally, the wet cleaning device 278 may be or include, for example, a wet floor cleaning apparatus, a window cleaner, a sweeper, or a wet vacuum cleaner, such as a canister, a stick, or an upright wet vacuum cleaner.

In a particular non-limiting example, wet cleaning device 278 is a battery-powered (or battery-powered) wet cleaning device, such as a battery-powered (or battery-powered) wet mopping apparatus, wherein under-voltage generator 178 (e.g., a pump) is powered (or is powered) by a battery electrically connected (or electrically connectable) thereto. As a result of the above-described power consumption reduction effect, which is specifically mentioned for this example, the power consumption reduction effect may be provided by the porous material 168 covering the dirty inlet(s) 142A, 142B, with suction from the under-pressure generator 178 being provided to the dirty inlet(s) 142A, 142B.

Fig. 42 schematically illustrates an exemplary wet cleaning device 278 in the form of a wet vacuum cleaner. In this non-limiting example, the wet cleaning device 278 includes the dirty liquid collection tank 310 and the clean liquid reservoir 313 described above. The cleaning head 100 comprised in the wet vacuum cleaner is movable over a surface 218 to be cleaned, in this example assisted by wheels 314 comprised in the wet vacuum cleaner.

In some examples, the wet cleaning device 278 may be or include a robotic wet vacuum cleaner or robotic wet mopping apparatus configured to autonomously move the cleaning head 100 over a surface to be cleaned (e.g., a surface of a floor).

Fig. 43 schematically illustrates an exemplary wet cleaning device 278 in the form of a robotic wet vacuum cleaner. The robotic wet vacuum cleaner may be autonomously moved over the surface 218 to be cleaned, for example by automatic control of the wheels 314.

During autonomous movement of the robotic wet vacuum, cleaning liquid stored in the cleaning liquid reservoir 313 may be delivered to the surface to be cleaned, and the liquid may be picked up and collected in the dirty liquid collection tank 310 via the covered dirty inlet(s) 142A of the cleaning head 100. The under-pressure generator 278/under-pressure generator device 280 and/or the cleaning liquid supply may also be automatically controlled.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims shall not be construed as limiting the scope.

Claims

1. A cleaning head (100) for a wet cleaning device, the cleaning head having:

at least one cleaning liquid outlet (104) through which cleaning liquid can be delivered;

a cleaning liquid applicator material (126, 128) arranged to apply the cleaning liquid to a surface to be cleaned;

at least one dirty inlet (142A, 142B); and

a porous material (168) covering the at least one dirty inlet, the porous material comprising a porous material layer (114), the porous material layer (114) being sealingly attached to the at least one dirty inlet, wherein the cleaning liquid applicator material is deformable to bring at least a portion of the cleaning liquid applicator material into contact with the porous material.

2. The cleaning head (100) of claim 1, wherein the cleaning liquid applicator material (126, 128) is deformable to bring an edge portion (136) of the cleaning liquid applicator material into contact with the porous material (168); optionally, wherein the edge portion of the cleaning liquid applicator material is arranged to contact the surface to be cleaned at least when the cleaning liquid applicator material is deformed.

3. The cleaning head (100) according to claim 1 or 2, wherein a liquid pick-up region (PR) of the porous material layer (114) is defined by a sealed attachment of the porous material layer around the at least one dirty inlet (142A, 142B), wherein the liquid pick-up region is arranged relative to each of the at least one cleaning liquid outlet (104) such that the liquid pick-up region is bypassed by the cleaning liquid delivered towards the surface to be cleaned.

4. A cleaning head (100) according to claim 3, comprising at least one cleaning liquid distribution portion (108, 124) in which the at least one cleaning liquid outlet (104) is arranged, wherein each of the at least one cleaning liquid distribution portion (108, 124) is spatially separated from the liquid pick-up region (PR).

5. The cleaning head (100) according to any one of claims 1 to 4, comprising:

-a portion (120) for facing the surface to be cleaned; and

a protruding element (252) mounted adjacent to the portion, the protruding element protruding from the cleaning head in the direction of the surface to be cleaned, wherein the protruding element comprises the porous material (168).

6. The cleaning head (100) of claim 5, wherein the cleaning liquid applicator material (126, 128) is deformable to bring the at least a portion of the cleaning liquid applicator material into contact with the porous material (168) between the protruding element (252) and the portion (120).

7. The cleaning head (100) according to claim 5 or 6, wherein the protruding element (252) has a curved surface arranged to contact the surface to be cleaned.

8. The cleaning head (100) according to any one of claims 5 to 7, wherein the protruding element (252) comprises an elastomeric material (238), the porous material (168) being arranged on the elastomeric material, and/or the protruding element being resiliently mounted in the vicinity of the portion (120).

9. A cleaning head (100) according to any one of claims 5 to 8, comprising a further portion (122) for facing the surface to be cleaned, wherein the protruding element (252) is mounted between the portion (120) and the further portion, allowing the cleaning head to swing forward on the protruding element to bring the portion into contact with the surface to be cleaned and back to bring the further portion into contact with the surface to be cleaned.

10. The cleaning head (100) of claim 9, wherein the cleaning liquid applicator material (126, 128) comprises a first applicator portion (126) and a second applicator portion (128), the first applicator portion (126) being included in the portion (120) and the second applicator portion (128) being included in the further portion (122), wherein the first applicator portion is deformable to bring at least a portion of the first applicator portion into contact with the porous material (168) between the portion and the protruding element (252), and wherein the second applicator portion is deformable to bring at least a portion of the second applicator portion into contact with the porous material between the further portion and the protruding element.

11. The cleaning head (100) according to any one of claims 1 to 10, wherein the cleaning liquid applicator material (126, 128) is separable from each of the at least one cleaning liquid outlet (104); and/or at least a portion of the porous material (168) is separable from each of the at least one dirty inlet (142A, 142B).

12. The cleaning head (100) according to any one of claims 1 to 11, wherein the porous material (168) comprises a plurality of layers of different colors that gradually wear through use of the cleaning head such that the color of the porous material acts as a wear indicator.

13. The cleaning head (100) according to any one of claims 1 to 12, wherein the porous material (168) comprises one or more further layers of porous material (156, 158).

14. A wet cleaning device comprising:

the cleaning head (100) according to any one of claims 1 to 13; and

an under-pressure generator (178) for providing suction to the at least one covered dirt inlet (142A, 142B).

15. The wet cleaning device according to claim 14, wherein the wet cleaning device isWet mopping devices, and/or wherein the under-voltage generator (178) is configured to generate a voltage by providing a voltage at 15cm ³ Per minute to 2000cm ³ Per minute, 40cm ³ Per minute to 2000cm ³ Per minute, more preferably 80cm ³ Per minute to 750cm ³ Per minute, and most preferably 100cm ³ Per minute to 300cm ³ Flow in the range of/min to provide the suction.