EP3323950A1

EP3323950A1 - Foam buffer and washing station

Info

Publication number: EP3323950A1
Application number: EP16199907.3A
Authority: EP
Inventors: Vincent Vaucher; Ismaël Düscher
Original assignee: Smixin AG
Current assignee: Smixin AG
Priority date: 2016-11-22
Filing date: 2016-11-22
Publication date: 2018-05-23

Abstract

The invention is in the field of low flow rate washing stations. A foam buffer (1) is provided that comprises an inlet (2) equipped for connecting the foam buffer (1) to a sink (30) of the washing station in a hydrological manner, an outlet (3) equipped for connecting the foam buffer (1) to a siphon (32) of the washing station in a hydrological manner, and a chamber (4) having a width (4.1) and a height (4.2), whereby the chamber (4) is arranged between the inlet (2) and the outlet (3), and the width (4.1) of the chamber (4) is larger than its height (4.2).

Description

The invention is in the field of water stations and concerns a washing station, in particular a washing station that guarantees an economical use of water, i.e. a so-called low flow rate washing station.
A washing station is a low flow rate washing station only if it fulfills demands set by authorities. In the case of a low flow rate hand washing station, the flow rate must not exceed 6 liters per minute, for example. However, there is an increasing demand for reduction of flow rates. Said demand is also triggered by recommendations and restrictions that consider the configuration and use of the washing station, too. In the case of handwashing stations, flow rates of even below 1 liter per minute are envisioned.
The demand for low flow rates in combination with the mandatory use of soap in a washing station causes the problem that the foam created by the soap does not get rinsed away and destroyed by a flow of water. As a result, the siphon of the washing station gets filled with foam and the foam rests in or swells back into the drain pan or sink of the washing station. This increases sedimentation in the washing station and has an impact on needed cleaning cycles, the accumulation of bacteria in the drain pan or sink and visual impression of the washing station.
The more intuitive term "sink" is used for the unit of the washing station that collects liquid dispensed by the washing station or dispensed into the washing station, in the following. This means that - depending on the kind of washing station - the term "sink" may comprise drain pans for example known from showers devices, too.
Actually, there is no washing station available meeting the demand for a low flow rate and the elimination of foam in the sink. In particular, there is no washing station available that meets these demands by itself, i.e. not by adapting the soap and/or water used.
It is an objective of the present invention to provide a device that eliminates foam in a low flow rate washing station, in particular in the sink of the low flow rate washing station.
It is a further objective of the invention to provide such a device in a manner that it can be used to upgrade easily washing stations already in use.
It is a further objective of the invention to provide the device with features adapted for foam elimination, decreased sedimentation and/or monitoring of sedimentation.
It is yet a further objective of the invention to provide a washing station that meets the demands for low flow rate and foam elimination, in particular elimination of foam in the sink.
At least one of these objectives is solved by the invention as claimed in the claims.
A foam buffer according to the invention is adapted to the needs of a washing station, in particular a low flow rate washing station as mentioned above.
In particular, the foam buffer is adapted to a hand washing station. Said hand washing station may have a flow rate of below 6 liters per minute, in particular of below 2 liters per minute or of below 2 liter per minute. The flow rate may be around 0.6 liter per minute, for example.
The foam buffer comprises an inlet, an outlet and a chamber.
The inlet is equipped for connecting the foam buffer to a sink of the washing station in a hydrological manner. Said hydrological connection may be a direct connection between the foam buffer and the sink via the inlet, for example by the inlet comprising an inlet opening with a diameter that is adapted to a diameter of a drain of the sink, or it may be an indirect connection between the foam buffer and the sink via the inlet, for example by the use of an intermediate pipe that leads a liquid from the sink to the inlet.
The inlet may be arranged to position the foam buffer relative to the sink and/or to mount the foam buffer to the sink. In particular, the inlet may make sure that the inlet opening coincides with the drain.
For example, the inlet may comprise a portion that surrounds a portion, e.g. an extension, of the drain circumferentially or that is surrounded by a portion of the drain circumferentially in the case of a foam buffer that is positioned correctly, when in use, relative to the sink. Generally, a correct positioning of the foam buffer relative to the sink comprises coincidence of the inlet opening with the drain such that no liquid and no foam leaks when flowing from the sink through the drain into the inlet opening and finally into the chamber.
The outlet is equipped for connecting the foam buffer to a siphon of the washing station in a hydrological manner, for example by means as described above. In the case of a siphon that is made of a pipe, the outlet may comprise an outlet opening with a diameter that is adapted to a diameter of the pipe, for example.
The outlet may be arranged to position the foam buffer relative to the siphon and/or to connect the foam buffer with the siphon in a hydrological manner. In particular, the outlet may make sure that the outlet opening coincides with an opening of the siphon (the "siphon opening").
For example, the outlet may comprise a portion that surrounds a part of the siphon or said pipe circumferentially or that is surrounded by a part of the siphon or pipe circumferentially in the case of a foam buffer that is positioned correctly relative to the siphon. Generally, a correct positioning of the foam buffer relative to the siphon comprises coincidence of the outlet opening with the opening of the siphon such that no liquid and no foam leaks when flowing from the chamber through the outlet opening into the siphon.
The chamber of the foam buffer has a width and a height.
In addition, the chamber of the foam buffer may comprise a volume. This volume may be a closed volume except for the inlet and outlet. However, said volume may be an open volume, in particular by a chamber being partly or completely open at its top.
In an embodiment with a chamber being partly or completely open at its top, the chamber may be formed such that a surface of the sink forms a top cover of the chamber when the foam buffer is mounted in the washing station.
In addition or alternatively, the chamber with a partly or completely open top may be arranged such that a plane comprising the opening at the top of the chamber is at a higher level than a plane comprising the drain of the sink when the foam buffer is mounted in the washing station. By doing so, foam and/or liquid becomes visible in the sink before it flows out from the chamber via the opening at its top.
The chamber of a foam buffer according to the invention is arranged between the inlet and the outlet and has a width that is larger than the height. In particular, the chamber is arranged between the inlet and the outlet such that a liquid and/or foam can enter the chamber trough the inlet and leave the chamber trough the outlet.
In many embodiments, the height of the chamber corresponds to the distance between the plane comprising the region in which liquid and/or foam enters the chamber and the plane comprising the region in which the liquid and/or foam leaves the chamber.
In the case of a foam buffer that is installed in a washing station, the width corresponds to a horizontal extension of the foam buffer and the height corresponds to a vertical extension of the foam buffer, generally.
The use of a width that is larger than the height has at least the following two positive effects: First, foam entering the chamber through the inlet can spread over a larger area compared to the case of a chamber with a height that is larger than its width. Hence, the foam has a larger surface area and dries faster. Second, the foam buffer can be installed under the sink where there is place for a foam buffer.
In embodiments in which the chamber has a circular horizontal cross-section or a circular horizontal cross-section except in a region in which the chamber tapers towards the outlet, the width corresponds to the diameter of the cross-section.
However, in embodiments in which the chamber has a non-uniform shape, for example by comprising a pronounced, e.g. steep, distinct portion that tapers towards the outlet, an average height and/or an average width is to be used instead of the overall height and width.
In an embodiment, the width of the chamber is larger than its height. In particular, the width is at least 1.5 times or twice the height.
As mentioned above, the width and height may be the absolute width and height, the average width and height, or a combination between an absolute and an averaged value in dependence of the shape of the chamber. In the case of a chamber with a portion that tapers towards the outlet, the width may be on average at least 1.5 times the absolute height of the chamber.
In an embodiment, the foam buffer further comprises the siphon.
In particular, the siphon can be integral with the chamber by being bonded or welded to the chamber, for example. It is also possible that siphon and chamber are fabricated such that they are integral. For example, chamber and siphon may be printed with a 3D-printer, molded or cast.
An advantage of an integral realization of chamber and siphon is that the size of the resulting foam buffer can be adapted to requirements given by a washing station. In particular, the foam buffer can have a low overall height that corresponds to the siphon that is to be replaced or that corresponds to the space available under the sink of a washing station in use, for example.
Siphon and chamber may be one piece. It is also possible that the foam buffer in total is one piece.
In embodiments in which the foam buffer comprises the siphon, the siphon may be regarded as a siphon with the specific function of the foam buffer. In other words: A foam buffer with a siphon is equivalent to a siphon arranged for foam buffering.
If the siphon is integral and/or one piece with the chamber, the outlet is integral and/or one piece with the chamber and the siphon, too. In particular, the outlet may not be recognizable as an independent part of the foam buffer.
In an alternative embodiment of a foam buffer that comprises the siphon, the siphon can be mounted to the chamber in a detachable way. Such a construction of the foam buffer simplifies installation of the foam buffer and is advantageous in the case when a foam buffer is installed in a washing station in service in order to upgrade it.
In embodiments of the foam buffer comprising the siphon, the volume of the chamber can be larger than a volume of the siphon. By doing so, the chamber acts as a real buffer compared to a siphon without an upstream chamber.
In embodiments of the foam buffer comprising or not comprising the siphon, in particular in embodiments directed towards the use in hand washing stations, the volume of the chamber is at least 0.4 liter (0.0004 m³). However, said volume may be adapted to the concrete configuration of the washing station, for example the kind and/or dimensions of the washing station, the used soap, the mixing ratio between soap and water etc., and to the siphon.
For example, the volume can be between 0.5 and 4 liters, in particular between 1 and 3 liters. Such volumes are suitable for hand washing stations, in particular.
In an embodiment, the foam buffer comprises at least a first part and a second part, wherein the first part and the second part being detachable, such that a user can access the inside of the foam buffer, in particular the inside of the chamber and the inlet and outlet, in order to clean the foam buffer.
For example, the foam buffer can have a detachable cover. In operation, the detachable cover can be rigidly connected to the chamber, e.g. by use of a bayonet joint. Alternatively or in addition, the chamber can be fabricated in two parts such that the two parts can be separated and joint reproducibly and such that one part does not change its position between the inlet and the outlet. In other words: the chamber can be opened without removing it.
In particular, the foam buffer comprises two parts.
Residuals are created in the place where foam decomposes, especially if the foam decomposes under dry conditions, i.e. if no or little water is supplied. In the following, these residuals are called "sediments".
In an embodiment, the foam buffer further comprises a sediment sensing arrangement that is arranged to determine a level of sediments in the chamber. The level of sediments may be given by a sediment height, a sediment width and/or a sediment volume, for example.
The sediment sensing arrangement comprises a sensor. Preferably, at least this sensor is positioned inside the chamber. In order to avoid errors in the measured sediment level, the foam buffer may be equipped for at least one of:

Determination of the time passed since the last usage of the washing station. In this case, the foam buffer or the sediment sensing arrangement itself may be configured to start a measurement of the sediment level after a defined period of time of non-use of the washing station, only. For example, this period of time is longer than 2 hours, in particular between 5-12 ours (non-use over night) or between 24 and 48 ours (non-use over weekend).
Determination of the presence of foam, e.g. by measuring the light scattering properties within the chamber. In this embodiment, the foam buffer may further comprise a light source, e.g. a laser or a lamp that generates the light that is scattered towards the sensor or an additional sensor. In the case of determining the presence of foam, a measurement of the sediment level is only started if no foam is present.

In addition, the sediment sensing arrangement may be equipped to generate an output signal in the case a sediment level has been measured that requires cleaning of the foam buffer.
For example, the sediment sensing arrangement generates an output signal if the measured sediment height is larger than 1 cm and/or if the chamber volume is reduced significantly, for example by 15%, 20% or 30%.
In addition or alternatively to a sediment sensing arrangement, the foam buffer may comprise a counting unit that counts usage cycles. The counting unit may be equipped to generate an output signal in the case a number of cycles has been counted that requires cleaning of the foam buffer.
In an embodiment, the foam buffer comprises an aeration element that contributes to foam elimination. In particular, the aeration element fastens foam decomposition, e.g. by expose it to fresh air, draught, ventilation and/or an increased, changed or changing air pressure.
At least in the context of a foam buffer that comprises an aeration element, foam decomposition and foam elimination means that the bubbles constituting the foam are destroyed or reduced in size. The latter leads to bubbles that flow better towards the outlet and through the outlet and siphon. However, foam can also be eliminated from a portion of the washing station, e.g. from the sink or the chamber, by letting it flow away or by causing it to flow away.
In particular, the aeration element comprises at least one of:

An air-inlet opening. The air inlet-opening may be an opening in the chamber that connects the inside of the chamber with an outside of the chamber. Such an opening in the chamber is at a top region of the chamber, preferably.

In the case of a chamber that is partly or completely open at its top, the opening at the top may be the air-inlet opening or part of it.
Preferably, the air-inlet opening is at a horizontal plane that is higher (with respect to the ground) than a horizontal plane comprising the drain or any other part of the sink. By doing so, foam or liquid becomes visible in the sink before any foam or liquid leaks through the air-inlet opening, e.g. in the event that the siphon is clogged.
The aeration element that comprises an air-inlet opening may further comprise an assembly for preventing foam to leak through the air-inlet opening or to leak through the air-inlet opening without being noticed by the user. This assembly is called the "safety assembly" in the following. For example, the safety assembly is needed in the case of an air-inlet opening that is not at a horizontal plane that is higher than a horizontal plane comprising the drain or any other part of the sink.
For example, the safety assembly may comprise a venting channel, e.g. a tube, that shifts the air-inlet opening to a horizontal plane that is higher than a horizontal plane comprising the drain or any other part of the sink.
The safety assembly may comprise a membrane arranged to let air enter the chamber and to prevent foam and/or liquid to leak out of the chamber.

A fan. The fan may be positioned in the chamber or outside the chamber. In the latter case, the fan acts through an air-inlet opening, e.g. an air-inlet opening as described above.

In an embodiment, the foam buffer comprises a foam elimination member, in particular an active foam elimination member, i.e. a foam elimination member that comprises a movable part that acts directly or indirectly on the foam.
At least in the context of a foam buffer that comprises a foam elimination member, foam elimination means that the bubbles constituting the foam are destroyed or reduced in size. The latter leads to bubbles that flow better towards the outlet and through the outlet and siphon. However, foam can also be eliminated from a portion of the washing station, e.g. from the sink or the chamber, by letting it flow away or by causing it to flow away.
The foam elimination member may comprise at least one of:

A centrifugation unit adapted to spin a part of the foam buffer around an axis.
A grid, sieve and/or breaking wall that is/are movable relative to the chamber or any other foam bearing surface. Grid, sieve and/or breaking wall may be arranged to cause mechanical destruction of the foam.

In an embodiment, the foam buffer comprises a hydrophilic surface arranged to promote foam diffusion and/or foam elimination, for example foam elimination that results from foam diffusion.
In particular, the hydrophilic surface is such that it destabilizes the foam in contact with the hydrophilic surface.
A hydrophilic surface promotes spreading of the liquid and bubbles over the surface, and thereby drying and/or destruction of bubbles by reducing the bubble film thickness.
Preferably, the hydrophilic surface of the foam buffer is at least part of the surface defining the inside space of the chamber. In this case, the hydrophilic surface may be arranged to spread the foam and fill the foam buffer.
In particular, the hydrophilic surfaces may be surfaces of the chamber that are vertical or close to vertical and/or overhanging surfaces, e.g. the surfaces forming a top region of the chamber.
In an embodiment, the foam buffer comprises a hydrophobic surface that promotes flow of sediments such that at least one of flow of the sediments towards the siphon and outflow of the sediments through the siphon is established.
Preferably, the hydrophobic surface is at least part of the surface defining the inside space of the chamber. In this case, the hydrophobic surface may be arranged to direct the sediments towards the siphon.
In particular, any portion of the chamber that tapers towards the siphon may have the hydrophobic surface.
In addition or alternatively, the inside of the outlet and/or the inside of a part or of the whole siphon may comprise the hydrophobic surface.
The hydrophobic surface may be or may comprise a structure and/or material that promotes the lotus effect.
In an embodiment, the foam buffer comprises a hydrophilic surface and a hydrophobic surface of the kind describe above. In particular, surfaces defining the inside of the chamber that are essentially vertical and/or overhanging may be hydrophilic whereas surfaces tapering towards the siphon and/or surfaces with a low inclination angle may be hydrophobic.
In addition or alternatively to the surface defining the inside space of the chamber being hydrophilic, hydrophobic or partly hydrophilic and partly hydrophobic, said surface may be treated for chamber sterilization. For example, said surface may comprise silver particles
In an embodiment, the foam buffer comprises a self-cleaning unit. The self-cleaning unit comprises at least one of

A vibrating system. In particular, the vibrating system puts at least a part of the foam buffer in vibration. For example, the part set in vibration can be chamber or part of the chamber, e.g. the region tapering towards the siphon or part of that region, and/or the outlet and/or the siphon or the part of the siphon directed towards the chamber or outlet.
A nozzle that dispenses a liquid, in particular water, of a pressure capable of removing the sediments from the surface defining the inside of the chamber. In other words, the nozzle sprays a liquid, e.g. water, of high pressure into the inside of the chamber.
The nozzle may be arranged inside the chamber or act through a nozzle opening in the wall defining the chamber.
The nozzle is arranged to direct the liquid to different position on the surface defining the inside of the chamber. This can be done by a movable nozzle or by a nozzle comprising a liquid directing unit. For example, the nozzle can dispense the liquid in a cone-like manner wherein the opening angle of the cone is reduced during self-cleaning.
A brush that is movable over at least the surface defining the interior of the chamber or a part of it and/or the outlet and/or the siphon or the part directed towards the chamber or outlet.

For example, the brush can be mounted rotatably in the chamber.
Any embodiment of the foam buffer can be realized as an upgrade unit. The upgrade unit can comprise the foam buffer with or without siphon and/or with or without sink. In particular, the upgrade unit comprises the siphon in addition to the foam buffer.
Any embodiment of the foam buffer may further comprise a distributor that mixes an additive adapted to promote foam elimination into at least one of the water and the foam. Mixing the additive into the foam may be done by spraying it over or into the foam, e.g. when the foam is in the chamber or the inlet.
The additive may promote foam elimination, for example by causing the foam wall to thin and collapse.
The additive may comprise silicone and/or it may be a silicone based substance.
In particular, the additives are so-called "defoamers" or "anti-foaming agents".
None, one or more features, specific elements, components and device parts of the embodiments described above can be present in a foam buffer according to the invention. In particular, this concerns the siphon, the multi-part foam buffer, the sediment sensing arrangement, the aeration element, the foam elimination member, the hydrophilic surface, the hydrophobic surface and the self-cleaning unit as well as features related to said components.
Furthermore, the invention concerns a washing station that comprises a foam buffer according to the invention, in particular according to any of the above-described embodiments of the foam buffer.
In particular, the washing station may be a hand washing station.
In an embodiment, the washing station comprises the sink and the siphon, wherein the foam buffer is placed between the sink and the siphon and wherein the inlet of the foam buffer is connected to the sink in a hydrological manner and the outlet of the foam buffer is connected to the siphon in a hydrological manner.
The foam buffer may be placed below the sink, generally. However, the foam buffer or part of the foam buffer may also be placed somewhere else. In the case of a washing station that is used from a well-defined user-side, e.g. given by a tap and/or the presence of a wall to which the washing station is mounted, the foam buffer or part of it may be placed towards the side opposite to the user-side. The position of the drain and/or siphon may be adapted accordingly, for example in order to shorten the length of the inlet.
Exemplarily embodiments of the invention are shown in the following figures. In the figures, the same reference symbol is used for identical or comparable elements. It shows:

Fig. 1; a cross-section through a foam buffer;
Fig. 2; the foam buffer of figure 1 with detached cover before mounting to a sink;
Figs 3-5; perspective views of the foam buffer from the side (fig. 3), from the top (fig. 4) and from the bottom (fig. 5);
Fig. 6: a cross-section through a foam buffer (without cover) comprising a siphon;
Fig 7: a perspective view of the foam buffer from the side (without cover);
Fig. 8: a perspective view of the foam buffer comprising a siphon from the bottom;
Fig. 9: a cross-section through a foam buffer comprising an aeration element;
Fig. 10: a cross-section through a foam buffer comprising a sediment sensing arrangement; and
Fig. 11: a cross-section through a foam buffer comprising a foam elimination member.

Figure 1 shows a cross-section through a foam buffer 1. The foam buffer 1 comprises a first part 1.1 and a second part 1.2. The first and the second part are detachably mounted to each other, for example by the use of a bayonet joint 8 or a snap lock. When mounted to each other, the first part 1.1 and the second part 1.2 form a chamber 4.
In the embodiment shown in figure 1 , the first part 1.1 is a cover 5 comprising an inlet 2 with an inlet opening 6. The second part 1.2 forms the side-walls and the bottom of the chamber 4 and comprises an outlet 3 with an outlet opening 7. In use, the chamber is connected hydrologically, i.e. direct or indirect by the use of an intermediate pipe for example, through the inlet 2 to a sink 30 as shown in figure 9 and through the outlet 3 to a siphon 32, as shown in figure 6 , for example. Thereby, liquid and foam can enter the chamber 4 via the inlet opening 6 and leave the chamber 4 via the outlet opening 7.
The cover 5 comprises a fixation mechanism 9 in order to fix the cover 5 to the sink 30 or to the intermediate pipe. In the embodiment shown, the fixation mechanism 9 is a screw clamping connection, i.e. a connection in which the inlet 2 (or part of it) and a portion of the sink 30, e.g. an extension 34 of a drain 31, or of the intermediate pipe are pressed against each other in reaction to a rotational movement initiated by the user. The pressure needed to hold the cover 5 and the corresponding portion of the sink 30 or the intermediate pipe together can be generated by a conical element 14, for example.
The chamber 4 has a width 4.1 and a height 4.2, wherein the width 4.1 is larger than the height 4.2.
In the shown embodiment, the chamber 4 has essentially the basic shape of a cylinder, unless a portion of the chamber 4 that tempers towards the outlet 3. However, the chamber 4 may have any other basic shape apart from the shape of a cylinder, for example the shape of a cuboid or any shape with a polygonal or elliptical horizontal cross-section.
It can be shown that a width 4.1 between 10 and 30 cm and a height 4.2 between 5 and 10 cm yields good results concerning foam buffering at least when using a cylinder-like chamber 4 in combination with siphons 32 typically used with hand washing stations. In particular, a width 4.1 between 15 and 25 cm and a height 4.2 between 5 and 7.5 cm, resulting in chamber volume between 0.9 and 3.7 liters is preferred. In many cases, a chamber volume of around 2 liters, for example realized by a cylinder-like chamber 4 with a width 4.1 (diameter) of around 20 cm and a height 4.2 of around 6 cm, is sufficient.
Figure 2 shows the foam buffer 1 with detached cover 5 and before mounting to the sink 30. The sink 30 comprises the drain 31 with an extension 34 at its bottom.
For mounting, the cover 5 is moved towards the sink 30 such that the extension 34 engages with the inlet 3 and the inlet 3 surrounds the extension 34 circumferentially. The cover 5 is then fixed to the sink 30 by the use of the fixation mechanism 9. In the embodiment shown, it is the cover 5 that comprises the fixation mechanism 9. Finally, the second part 1.2 of the foam buffer 1 forming the side-walls and the bottom of the chamber 4 is fixed to the cover 5 (i.e. to the first part 1.1 of the foam buffer 1) by the use of the bayonet joint 8.
The bayonet joint 8 comprises a first element 8.1 being arranged on the first part 1.1 of the foam buffer 1 and a second element 8.2 being arranged on the second part 1.2 of the foam buffer.
This way of mounting the foam buffer 1 to the sink 30 leads to a chamber 4 whose interior, i.e. the inside side-walls and the inside bottom but also the inlet 2 and outlet 3, can be made accessible easily. In particular, the interior can be made accessible without the use of any tools, without untightening the fixation between the foam buffer 1 and sink 30 and hence without risking to establish a leak during cleaning, for example.
The embodiment shown in figure 2 comprises further the optional feature of a hydrophilic surface 27 and of a hydrophobic surface 28. The portion of the inside wall of the chamber 4 that defines the bottom of the chamber 4 comprises the hydrophobic surfaces 28. Any portion of the inside wall of the chamber 4 that defines the side wall of the chamber comprises the hydrophilic surface 27. By doing so, foam elimination is promoted where the foam is in contact with the side wall of the chamber 4 and the outflow of sediments through the outlet 3 is promoted at the bottom of the chamber 4 where most sediments accumulate.
Independent of the presence of the hydrophobic surface 28, the shape of the bottom of the chamber 4 is adapted to increase sediment outflow through the outlet 3. This is done by a bottom that tapers towards the outlet 3. Thereby, the bottom may taper towards the outlet 3 under a varying angle, e.g. under an increasing angle as shown in figure 2 .
Figure 3 shows the foam buffer 1 from the side, wherein the first part 1.1 (the cover 5 in the embodiment shown) and the second part 1.2 are mounted to each other by the use of the bayonet joint 8.
The fixation mechanism 9 comprises a corrugated surface 11 for easier initiation of the rotational movement and for establishing an increased fixation compared to the use of a flat surface.
The outside region of the second part 1.2 of the foam buffer 1 comprises holding extensions 10. These extensions 10 are adapted to improve a grip on the foam buffer land to simplify the mounting of the second part 1.2 to the first part 1.1.
In the embodiment shown in figure 3 , the siphon 32 (as shown in figure 6, for example) is connected to the foam buffer 1 via the outlet 3.
For mounting the siphon 32 and the foam buffer 1 to each other, the outlet 3 of the foam buffer 1 is pushed into a siphon opening such that it is surrounded by the portion of the siphon 32 directed towards the foam buffer 1.
In particular, the outlet 3 is inserted into the siphon 32 such that a distal end of the outlet 3 is plunged into the stagnant water of the siphon 32. However, it is also possible that the distal end of the outlet 3 does not reach the stagnant water. This allows easier unmounting of the siphon 32 and/or the foam buffer 1 or its second part 1.2.
The foam buffer 1 shown in figure 3 comprises reinforcement protrusions 13. Said reinforcement protrusions 13 reinforce mechanically the region around the outlet 3. In other words, the reinforcement protrusions 13 increase the stability of the foam buffer 1 in case of load. In particular, they make sure that the tapering towards the outlet 3 is unchanged when the second part 1.2 is loaded by an internal (for example water) or external (for example loads that apply during mounting or dismounting) load.
Figure 4 shows the foam buffer 1 according to figure 3 from the top. The foam buffer 1 comprises the cover 5 that is mounted to the second part 1.2 of the foam buffer 1 by bayonet joints 8. The cover comprises the inlet 2 with the inlet opening 6 and the fixation mechanism 9 comprising the corrugated surface 11.
Figure 5 shows the foam buffer 1 according to figure 3 from the bottom. The foam buffer 1 comprises a bottom of the chamber 4 that tapers towards the outlet 3 with the outlet opening 7.
In the embodiment shown, the reinforcement protrusions 13 extend radially from the outlet 3 towards the side-walls of the foam buffer 1.
Figure 6 shows a cross-section though a foam buffer 1 comprising the siphon 32. The siphon 32 is one piece with the second part 1.2 of the foam buffer 1. Further, the siphon 32 is formed such that it connects horizontally to a drainpipe. This form of the siphon 32 has at least one of the following effects:

It allows for an easy exchange of a siphon 32 in use that does not comprise a foam buffer 1 by a siphon 32 with integrated foam buffer 1, especially if the foam buffer 1 comprises a reliable, easy-to-install fixation of the foam buffer 1 to the sink 30, e.g. by the fixation mechanism 9 as shown in figure 1 and figure 2 . It goes without saying that a foam buffer 1 that comprises the siphon 32 may be seen as a siphon 32 that comprises a foam buffer 1.
The siphon 32 can be connected to the drainpipe by pushing an end of the siphon 32 into an opening of the drainpipe, i.e. there is no need for a sophisticated connection mechanism. In particular, this is the case when the foam buffer 1 comprises a reliable fixation of the foam buffer 1 to the sink 30 or the intermediate pipe, e.g. by the fixation mechanism 9 as shown in figure 1 and figure 2 .

Figure 7 shows a perspective view of a foam buffer 1 comprising the siphon 32. The foam buffer 1 is shown without first part 1.1 (in the embodiment shown, this means without cover 5) such that portions of the side-walls and of the tapering bottom of the chamber 4 are visible.
In the shown embodiment, the second part 1.2 comprises a collar 33 that surrounds circumferentially the portion of the chamber wall directed towards the cover 5, when the foam buffer 1 is in use.
The collar 33 extends from the exterior side-wall of the chamber 4 and runs in a direction towards the cover 5 (when the foam buffer 1 is in use) wherein the collar 33 runs in said directions in a manner that it is spaced from the portion of the chamber wall directed towards the cover 5 in the outmost region of said portion, at least.
In the embodiment shown, the portion of the second part 1.2 that faces the cover 5 is essentially "U"-shaped.
A corresponding, e.g. circumferential, protrusion 35 of the cover 5 (as shown in figure 10 , for example), can be positioned in said space between chamber wall and collar 33 such that the second part 1.2 and the cover 5 can be connected in a liquid- and foam tight manner.
If the corresponding protrusion 35 of the cover 5 is "U"-shaped too, a double level concentric lip 24 is realized.
An essentially "U"-shaped geometry of the collar 33 in combination with a "U"-shaped corresponding protrusion 35 of the cover 5 allows further to compensate for fabrication tolerances. For example, if the collar 33 produced has a diameter larger than aimed for, the inside lip will do the tightness. However, if the collar 33 has a diameter smaller than aimed for, the tightness will be done by the external lip. In both case the material is never over stressed by compression or expansion.
Each bayonet joint 8 comprises a first element 8.1 that is arranged on the cover 5 and a second element 8.2 that is arranged on the second part 1.2 of the foam buffer 1.
The bayonet joint 8 is designed such that a force in vertical direction needed to lock the second part 1.2 to the cover 5 leads to a widening of the space between the collar and the chamber wall. This allows for easy introduction of the protrusion 35 of the cover 5 and avoids unfavorable clamping effects during the locking of the second part 1.2 to the cover 5.
In the sown embodiment, the second elements 8.2 are arranged equidistantly along the collar 33.
Figure 8 shows a perspective view of a foam buffer 1 that comprises a siphon 32 from the bottom. The siphon 32 and the second part 1.2 of the foam buffer 1 may be a single part produced out of a single plastic injection molding step.
Alternatively, the siphon 32 and the second part 1.2 of the foam buffer 1 may be glued, welded or clipped to each other, for example.
Figure 9 shows a cross-section through a foam buffer 1 comprising an aeration element 20. The aeration element 20 comprises an air-inlet opening 21 and a venting channel in the shape of an aeration tube 40. The aeration tube 40 is fixed to the outside of the air-inlet opening 21 in a liquid- and foam tight manner. The aeration tube 40 further comprises an aeration opening 41 that is in a horizontal plane that is higher from the ground than a horizontal plane comprising the drain 31 of the sink 30.
The aeration tube 40 has the effect that the effective opening of the air-inlet into the chamber 4 is shifted to the aeration opening 41. This is advantageous in the case of too much foam in the chamber 4 because the foam becomes visible in the sink 30 before it leaks out of the chamber 4 via the air-inlet opening 21.
In particular, the aeration tube 40 may be flexible. This allows for adaptation to any sink shape and/or for sticking the aeration tube 40 on the sink 30. Additionally, the aeration tube 40 may be led through a through bore in the sink 30 such that any foam leaving the aeration opening 41 drops into the sink 30.
Alternatively or in addition, the aeration element 20 may comprise a membrane that is permeable for air but not for liquid and/or foam.
In the embodiment shown, the aeration element 20 comprises a variety of air-inlet openings 21 and aeration tubes 40. This increases the ventilation of the chamber 4 which promotes foam elimination further.
The aeration element 20 may comprise a fan 22 in addition or alternatively to the air-inlet opening 21 and the aeration tube 40 and/or membrane. The fan 22 promotes foam elimination by generating air swirling in the chamber 4 resulting in increased and/or varying air pressure on the foam.
The fan 22 may be placed inside the chamber 4, as shown in figure 9 , or outside the chamber. In the latter case, the fan 22 effects air swirling in the chamber 4 via openings in the chamber, for example the air-inlet opening 21 (with or without membrane), the aeration opening 41, or an opening at the top of the chamber given by a chamber without cover or by a cover with at least one opening.
The fan 22 can be switched on after a washing procedure performed by the washing station in which the foam buffer 1 is mounted automatically and it can be switched off automatically again. Switching off may be triggered by at least one of on-time and a measurement of foam presence in the chamber, e.g. by measuring the light scattering properties in the chamber.
In particular, the fan 22 can be a fan used for hand drying in a hand washing cycle of the washing station.
Figure 10 shows a cross-section through a foam buffer 1 comprising a sediment sensing arrangement 26. The sediment sensing arrangement 26 comprises a status lamp 26.3 and a sensor 26.1. The sensor 26.1 is arranged to measure or at least estimate the sediment thickness in the chamber 4. For example, the sensor 26.1 measures the distance between the sensor 26.1 and an area of the bottom of the chamber 4 or the optical properties of said area, e.g. its reflection and/or scattering properties.
The sediment sensing arrangement 26 may comprise a floater instead of the sensor 26.1 or in addition to the sensor 26.1. In particular, the floater is heavier than foam and lighter than all kind of sediments and/or grease.
The status lamp 26.3 is connected to the sensor 26.1 or floater and can be switched on by the sensor 26.1 or floater. The status lamp 26.3 is switched on when a sediment thickness was measured that necessitates cleaning of the chamber 4. Hence, the status lamp 26 indicates the need for chamber cleaning.
Alternatively or in addition to the sensor 26.1 or floater, the sediment sensing arrangement 26 comprises a counter 26.2. The counter 26.2 counts the number of washing cycles performed by the washing station. The counter 26.2 may be connected to the status lamp 26.3 and switch it on if a number of washing cycles was reached that necessitates cleaning of the chamber 4.
In addition or alternatively, the sediment sensing arrangement 26 may indicate the necessity of cleaning to a remote controller by a wired or wireless communication channel.
Figure 11 shows a cross-section through a foam buffer 1 comprising a foam elimination member 25. In the embodiment shown, the foam elimination member 25 comprises a breaking wall 25.1 and a suspension 25.2 comprising a rotatable protrusion 25.3.
The breaking wall 25.1 rotates inside the chamber 4 around a rotation axis given by the rotatable protrusion 25.3, wherein the breaking wall 25.1 is close to or in gliding contact to the bottom and side-wall of the chamber 4. The rotation of the breaking wall 25.1 has two effects in particular: First, foam is eliminated by the mechanical impact of the breaking wall 25.1. Second, foam is directed towards the outlet 3.
The breaking wall 25.1 may have a shape that supports directing foam from a region close to the cover 5 and/or from a region close to the side-wall of the chamber 4 towards the outlet 3. For example, the breaking wall 25.1 may be mounted under an angle relative to the rotation axis such that a top region of the breaking wall 25.1 is in the direction of breaking wall movement overhanging relative to a bottom region of the breaking wall 25.1. In other words: the top region of the breaking wall 25.1 runs ahead of the bottom region of the breaking wall 25.1.
In addition or alternatively, the breaking wall 25.1 may have a curved shape in a cross-section perpendicular to the rotation axis such that foam is directed from regions close to the side-wall of the chamber 4 to the outlet 3.
The bottom of the chamber is preferably tapered towards the outlet 3 which reduces the need of a breaking wall 25.1 curved in a cross-section perpendicular to the rotation axis.
The breaking wall 25.1 may have a surface that promotes foam elimination, e.g. by being structured, and/or may be hydrophobic.
The rotation of the breaking wall 25.1 can be switched on after a washing procedure performed by the washing station in which the foam buffer 1 is mounted automatically and it is switched off automatically again. Switching off may be triggered by at least one of on-time and a measurement of foam presence in the chamber, e.g. by measuring the light scattering properties in the chamber.

Claims

A foam buffer (1) for use in a low flow rate washing station, the foam buffer (1) comprising
- an inlet (2) equipped for connecting hydrologically the foam buffer (1) to a sink (30) of the washing station,

- an outlet (3) equipped for connecting hydrologically the foam buffer (1) to a siphon (32) of the washing station,

- a chamber (4) having a width (4.1) and a height (4.2)
characterized in that the chamber (4) is arranged between the inlet (2) and the outlet (3), and in that the width (4.1) is larger than the height (4.2).
The foam buffer (1) according to claim 1, wherein the width (4.1) is at least 1.5 times the height (4.2).
The foam buffer (1) according to claim 1 or 2, wherein the foam buffer (1) comprises the siphon (32).
The foam buffer (1) according to claim 3, wherein the siphon (32) is integral with the chamber (4).
The foam buffer (1) according to claim 3 or 4, wherein the chamber (4) comprises a volume of the chamber (4) and wherein the volume of the chamber (4) is larger than a volume of the siphon (32).
The foam buffer according to any one of the previous claims, wherein the chamber (4) comprises a volume of the chamber (4) wherein the volume of the chamber is at least 0.4 liters.
The foam buffer (1) according to any one of the previous claims, wherein the foam buffer (1) comprises a first part (1.1) and a second part (1.2), the first part and the second part being detachable such that the chamber (4) can be cleaned.
The foam buffer (1) according to any one of the previous claims, further comprising a sediment sensing arrangement (26) arranged to determine a level of sediments in the chamber.
The foam buffer (1) according to any of the previous claims, comprising an aeration element (20) arranged to eliminate foam.
The foam buffer (1) according to claim 9, wherein the aeration element (20) comprises at least one of
- an air-inlet opening (21)

- a fan (22).
The foam buffer (1) according to any one of the previous claims, further comprising a foam elimination member (25).
The foam buffer (1) according to any one of the previous claims, wherein the chamber (4) comprises a hydrophilic surface (27) arranged to promote foam diffusion and/or elimination.
The foam buffer (1) according to any one of the previous claims, wherein the chamber (4) comprises a hydrophobic surface (28) arranged to promote flow of sediments towards the siphon (32) and/or through the siphon (32).
A washing station comprising a foam buffer (1) according to any one of the previous claims.
The washing station according to claim 14, further comprising a sink (30) and a siphon (32), wherein the foam buffer (1) is placed between the sink (30) and the siphon (32) and wherein an inlet (2) of the foam buffer (1) is connected hydrologically to the sink (30) and an outlet (3) of the foam buffer (1) is connected hydrologically to the siphon (32).