EP0797484B1

EP0797484B1 - Method and apparatus for the application of a cleansing or disinfecting foam on a surface

Info

Publication number: EP0797484B1
Application number: EP95901622A
Authority: EP
Inventors: Steven Mulder; Frank Paul Herman De Block-Bury
Original assignee: BLOCK BURY FRANK PAUL HERMAN D; De Block-Bury Frank Paul Herman
Current assignee: De Block-Bury Frank Paul Herman
Priority date: 1993-11-17
Filing date: 1994-10-10
Publication date: 1999-10-20
Anticipated expiration: 2014-10-10
Also published as: JPH09509090A; AU1078295A; DE69421297D1; WO1995013885A1; ATE185713T1; CA2176728A1; EP0797484A1; NL9301984A

Abstract

In a method for the application of a foam layer to a surface for the purposes of cleansing and/or disinfecting the surface, a concentrated high-pressure foam spray is sprayed at the surface under treatment from a large distance. An even distribution of the foam over the surface is achieved not as a result of the form of the jet, but rather as a result of the impact on the foam jet on the surface. In order to achieve this effect, the foam is sprayed at a distance of at least 4 meters from the surface, under a pressure of at least 4 bars and in a volume of at least 150 liters per minute at the surface being treated.

Description

The invention relates to a method for the application of a layer of foam to a surface for the purposes of cleansing and/or disinfecting the surface, whereby foam emanating from a spray-head held at a distance from the surface is sprayed in volume and under pressure, whereby a layer of foam which uniformly covers the surface is formed.

The invention additionally relates to a foam-spraying apparatus for the implementation of the method, containing a spray-head, mixing means equipped with a number of connection-openings to which supply pipes are connected for the supply under pressure of water, compressed air and a foaming product, and a connecting pipe which connects the spray-head to a mixing channel.

The European patent application EP-A-0466663 describes and shows such a device for foaming a surface.

This device comprises a couple of tanks containing detergent and water respectively, which are held under air pressure during operation. Further this device comprises a lance having a mixing chamber.

In industry, it is common practice to use so-called foam-cleaning for the cleansing of floors, walls and machines. This is a procedure for the application of a detergent or other soaking agent, whereby use is made of the cleansing power of the product itself, or of an additive, in order to cover the surfaces to be cleansed with a layer of foam which remains more or less adherent to the surfaces for quite some time. Advantages of this method include, among others, the what longer contact time (foam dries more slowly than liquid product), the ready visualisation of the work done (it is immediately apparent which surfaces have already been treated and which have not), and the product-savings (the product adheres to the surface and does not flow immediately towards the floor). In the application of this procedure, it is usual to make use of a rate of some 40 to 100 liters of foam per minute at the spray-head. In order to cover as large a surface as possible, use is made of a foam-pistol, whereby the spray-head is formed by a so-called flat-jet nozzle which converts the foam spray into a flat, wide jet. The optimal results are obtained at a distance of the nozzle from the surface under treatment of some 2 to 3 metres; in this way, a surface with a width of 1 to 2 metres is covered in one sweep. If this distance is increased, then the jet begins to decompose into foam chunks and the surface is not sufficiently treated with one sweep of the foam pistol.

It is a goal of the invention to provide a method of the sort mentioned in the introduction, whereby the application of the foam layer proceeds much more quickly. To this end, the method in accordance with the invention has the features set out in claim 1 is sprayed with a concentrated jet under a pressure of at least 4 bars and in a volume of at least 150 liters per minute.

As a result of this method, a whole new effect arises for the spreading of the foam over the surfaces under treatment. The distribution of the foam no longer takes place by means of handling the surfaces with a wide jet, but by means of aiming a compact jet with considerable power at a surface, whereby the spreading of the foam is achieved by virtue of the impact of the jet. In order to achieve this effect, the flow-rate of the foam at the spray-head is increased to at least 150 liters per minute and the flat-jet nozzle is replaced with a round spray-head or its use is totally avoided.

In contrast with the known low-pressure foam method, whereby the foam is spread out from the spray-head in a V-jet and is thus applied to the surfaces, the method according to the invention works with a large-volume flow of foam under high pressure. As a result of this volume-flow which emanates from the spray-head with considerable force in a focused point-jet, the foam distribution is achieved by virtue of the impact on the surface being treated. With the method according to the invention, which is based on the effect of the impact of the foam on the surface, a time savings of some 70% or more can be achieved compared to the known low-pressure foam method. Where, for example, 30 minutes used to be necessary for a given surface, the treatment can now be realised in less than 10 minutes. A further advantage of the method is that it allows surfaces to be treated from large distances, whereby the assistance of such aids as lifts or ladders will be less frequently required. A result of this is that foam cleansing is likely to be carried out more often, leading to a further time advantage and improving the general hygiene inside and outside the companies.

An embodiment of a method is characterized in that the foam is sprayed at a distance of at least 4 meters from the surface, under a pressure of at least 4 bars and in a volume of at least 150 litres per minute at the surface.

It is true that the impact effect occurs at lower values of pressure and volume and at a smaller distance from the surface, but the advantage of the time-savings only really comes into play above the aforementioned minimum values.

A further embodiment of the method according to the invention is characterised in that the foam is sprayed at a distance of at least 8 meters from the surface, under a pressure of at least 5 bars and in a volume of at least 350 liters per minute at the surface. This method can be applied to advantage if larger surfaces need to be treated, provided that sufficient space is available to allow spraying from this necessarily large distance. The effect is achieved by means of a method which requires certain minimum values with respect to distance, pressure and volume, and which is not limited in any way to certain maximum values of distance, pressure and volume. In fact, in theory, all values above the aforementioned minima can be applied.

An advantageous embodiment of the method according to the invention is characterised in that the foam is sprayed at a distance of between 10 and 16 meters from the surface, under a pressure of between 5.5 and 6 bars and in a volume of between 400 and 600 liters per minute at the surface.

As far as the foam spraying apparatus is concerned, the method of the invention has the features set out in claim 3. Preferably the spray-head has a cylindrical shape and in that during operation of the apparatus, a pressure exists in the supply pipe for the foam products of at least 5 bars and a volume-flow is present with a rate of at least 0.3 liters per minute, and that, in the supply pipe for compressed air, a pressure of at least 5 bars exists, and that, in the supply pipe for water, a pressure of at least 5 bars exists and a volume-flow is present with a rate of at least 15 liters per minute, and that, in the connecting pipe close to the spray-head, a pressure of at least 4 bars exists and a volume-flow is present with a rate of at least 150 liters per minute. In this way, a sufficiently strong foam jet can be achieved to realise the new impact effect in accordance with the invention.

An advantageous embodiment of the foam spraying apparatus according to the invention is characterised in that during operation of the apparatus, a pressure exists in the supply pipe for the foam products of approximately 6 bars and a volume-flow is present with a rate of about 1.5 liters per minute, and that, in the supply pipe for compressed air, a pressure of at about 8 bars exists, and that, in the supply pipe for water, a pressure of approximately 6 bars exists and a volume-flow is present with a rate of about 30 liters per minute, and that, in the connecting pipe close to the spray-head, a pressure of about 5.5 bars exists and a volume-flow is present with a rate of about 400 liters per minute.

A first version of the invention contains a mobile reservoir with an automated filling installation. This is achieved by means of sucking a vacuum in the tank with the aid of a Ventur-apparatus, whereby the product is sucked out of its original packaging. During the operation of the apparatus, the vacuum pump is automatically rinsed.

Another version of the invention is additionally equipped with a level-indication on the tank, containing a float which rises and drops via a straight and a spiral-shaped guide, whereby a needle is made to turn, whereby the level of the reservoir can be read from a scale.

Other versions consist of apparatus such as the above-described, but equipped with two or more reservoirs for the same product or possibly for other products, with identical or varying dosage.

Another version of the invention is equipped with protection against wasting product: a water-controlled valve blocks the supply of compressed air to the reservoir if the water pressure is insufficient.

Another version of the invention is equipped with automatic air-bleeding when the tank is at rest.

Another version of the invention is equipped with two types of pistol; one for a flat, wide jet and one for a straight jet.

Another version of the invention is embodied with a bypass to go around the foam portion so that the system can be used for later rinsing purposes.

Another version of the invention is equipped with a selection-tap so that it is possible to operate with varying concentrations of the product.

The invention will be elucidated in an exemplary manner hereinafter on the basis of a drawing. To this end:

Figure 1 schematically depicts an exemplary embodiment of a foam spraying device,

Figure 2 depicts a second exemplary embodiment of a foam spraying device,

Figure 3 depicts a portion of the internals of a storage-tank belonging to the foam device.

Figure 1 schematically depicts an exemplary embodiment of a foam spraying device 1 which is constructed around a mixing channel 3 formed by a hollow metal cylinder which is connected to a spray-head 7 via a connecting pipe 5. The spray-head 7 has a circular-cylindrical form for the realisation of a concentrated foam spray 9. A connecting mouth 11 for the connection of a (non-depicted) high-pressure water supply is situated at one extreme of the mixing channel 3. Moreover, two further connecting

mouths

13, 15 are situated on the mixing channel 3. One of these connecting mouths 13 is connected via a supply pipe 16 to a storage tank 17 within which a foam product 19 is located. A supply pipe 21 for compressed air is connected to the other connecting mouth 15, which supply pipe can be connected with an extreme 23 of a (non-depicted) compressed-air source. The connecting pipe 21 has yet another branch 25 which leads to the supply tank 17, whereby the foam product 19 can be transported under pressure to the mixing channel 3.

In addition to the supply tank 17, it is possible to attach other (non-depicted) supply tanks with different foam products, whereby by means of switching the connection of the supply pipe 16 to another supply tank, it is possible to apply these other foam products. Instead of working with supply tanks, it is also possible to connect another dosage-system to the supply pipe 16. The total system can be affixed to a movable trolley and can also be equipped with a compressor for the provision of the compressed air. The spraying can be commenced by means of opening (non-depicted) external water and compressed air taps. As an alternative, taps can be mounted on the apparatus, with which taps the water current and compressed air current can be regulated. For the foam products, it is possible to use alkaline products with a pH value between 0 and 14, acidic foaming cleansing products or a disinfecting foaming product. The advantageous effect commences at a water-pressure value of 5 bars (preferably 10 bars) and a water current of 15 liters per minute (preferably 30 to 35 liters per minute). The supply tank and connecting mouth for compressed air are hereby connected to a compressed-air pressure of 5 bars (preferably 8 bars), whereby the foam product also enters the mixing channel at approximately the same pressure level. The volume flow of the foam product obtained in this manner amounts to at least some 0.3 liters per minute (preferably 1.5 to 1.75 liters per minute).

During operation, a foam spray of some 225 liters per minute (preferably 400 liters per minute) at a pressure of at least 4 bars (preferably 5.5 to 6 bars) can be realized at the spray-head with the aforementioned values. A foam layer 31 can be applied to the surface under treatment 29 (which can be, for example, a floor or wall of a workplace, for example, in the food industry), from a distance 27 from the spray-head 7 to the surface of at least 4 meters (preferably 10 to 16 meters). The invention can be applied in both mobile and stationary installations and can be implemented for one or more concurrent operators.

Figure 2 shows a second exemplary embodiment of a foam spraying device 1' in more detail. Compressed air is supplied via a first connecting tap 201, and the necessary water is supplied via a second connecting tap 202. The second connecting tap 202 is coupled to a water-reducer 204 via a connecting point 203 (which can be, for example, a so-called quick-release coupling). The water reducer 204 is coupled with a tap 205 for shutting off the water and the compressed air by means of a valve 218. The other side of the tap 205 is (additionally) coupled via a flow-back protection 206, an excess-pressure valve 207 and a fine-dosage regulator 208 to a collector 209.

The first connecting tap 201 is coupled via a tap-in point 215 (for example, via a quick-release coupling) and an air filter 216 to a compressed air pressure-regulator 217. The output of the pressure regulator is coupled to a valve 218 which is operated by the tap 205. The output of the valve 218 is connected via a regulating tap 221 and a non-return valve 222 with the collector 209. The foam supply can be made wetter or drier with the regulating tap 221.

The output of the pressure regulator 217 is also coupled to a three-way tap 225 for selecting either filling or emptying of a storage tank 234 for the foam product. An output of the three-way tap 225 is coupled to a valve 223 via a pressure regulator 226 and a non-return valve 227 so that the compressed air pipe can be bled via a quick-bleeding air valve 224.

The storage tank 234 is coupled with the collector 209 via a regulating valve 232 and a non-return valve 233. The storage tank 234 can be filled or emptied via a tap-in point 235 and a respective filling or emptying hose 236.

The output of the valve 218 is coupled to a quick-bleeder 224 via a non-return valve 220 so that the pressure of the storage tank 234 can be rapidly reduced via a non-return valve 230. The (water) supply 219 rinses a vacuum pump 229 during the delivery of foam.

The pressure in the storage tank is limited via an excess-pressure valve 231.

The operation of the foam spraying device 1' is as follows. After the storage tank 234 has been filled with foam concentrate (product) and the air supply 201 and the water supply 202 are connected, a collector 209 is filled with the product which is to be foamed. The output of the collector is coupled via a tap-in point 210 and a foam hose 211 via a blocking tap 212 to a foam-mouth, either for a straight jet or for a V-jet 214 (for a further explanation, see the general description accompanying figure 1).

Figure 3 depicts a portion of the internals of the storage tank 234, for the external read-out of the amount of foam concentrate in the storage tank.

An indicator 301 provides an indication of the amount of liquid in the tank. The indicator is mounted on a plate 303 which is placed in such a manner that it can be rotated on a pipe 312 which pipe is additionally used for the supply of compressed air or for the vacuum generation in the storage tank. A float-body 316 is also attached to this pipe 312, which float-body 316 moves upwards and downwards in unison with the level of the liquid.

The float-body is connected to the plate 303 via a spiral-shaped rod 7. During the respective rising and falling of the float-body, the spiral-shaped rod pushes (and thereby rotates) the plate 303.

In this exemplary embodiment, two floats 217 are coupled to the float-body 316. The compressed air is further let in to and out of the storage tank via an input and output 315, respectively. The product (foam concentrate) is let in to and out of the storage tank via an input/output 314.

Another embodiment of the system is equipped with a safety device on the respective filling and emptying hose so that in connected state the tank can only be emptied under low pressure (e.g. 0.5 bars) via the respective filling and emptying hose.

Claims

Method for applying a layer of foam to a surface for the purposes of cleansing and/or disinfecting the surface, whereby foam emanating from a spray-head held at a distance from the surface is sprayed in volume and under pressure, whereby a layer of foam which uniformly covers the surface is formed, which method is characterized in that a concentrated foamable product (19) is supplied by air-pressure from a tank (17, 234) to a mixing-chamber (3, 209), to which mixing chamber also air and water under pressure are separately supplied, which mixture of concentrated foamable product, air and water is supplied from the mixing chamber to the spray-head.
Method in accordance of claim 1, characterized in that the concentrated foam product, air and water are supplied to the mixing chamber at such pressure, that the mixture emanating from the spray-head is sprayed as a concentrated jet under a pressure of at least 4 bars and in a volume flow of at least 150 liters per minute.
Apparatus (1,1') for implementing the method in accordance with one of the previous claims, comprising one tank (17, 234), a spray-head (7, 123), a mixing chamber (3, 209) equipped with a number of inlet-openings to which supply lines are connected for supplying under pressure foamable product, water and compressed air and connecting line which connects the spray-head to the mixing chamber, characterized in that the mixing chamber comprises three inlet openings, whereby the inlet-openings are separately connected to a water supply line, a compressed air supply line and a supply line from the tank (17, 234) for supplying concentrated foamable product contained in the tank to the mixing chamber, and that the apparatus is provided with means for pressurizing the concentrated foamable product.
Apparatus (1,1') in accordance to claim 3, characterized in that the pressurizing means are formed by a connection line (25) between the tank and the compressed air supply line.
Apparatus (1,1') in accordance to claim 3 or 4, characterized in that the spray head has a cylindrical shape and that means are present for providing, in operation of the apparatus, a pressure in the supply line for the concentrated foam product of at least 5 bars and a volume-flow with a rate of at least 0.3 liters per minute, and in the supply line for compressed air, a pressure of at least 5 bars, and in the supply line for water a pressure of at least 5 bars and a volume flow with a rate of at least 15 liters per minute, and in the connecting line for mixture leaving the mixing chamber close to the spray-head, a pressure of at least 4 bars and a volume flow with a rate of at least 150 liters per minute.
Apparatus (1,1') in accordance to claim 5, characterized in that means are present for providing, in operation of the apparatus, a pressure in the supply line for the concentrated foamable product of at least 6 bars and a volume flow with a rate of at least 1.5 liters per minute, and in the supply line for compressed air, a pressure of at least 8 bars, and in the supply line for water a pressure of at least 6 bars and a volume flow with a rate of at least 30 liters per minute, and in the connecting line for the mixture leaving the mixing chamber close to the spray-head, a pressure of at least 5.5 bars and a volume flow with a rate of at least 400 liters per minute.
Apparatus (1,1') in accordance to claim 5 or 6, characterized in that the apparatus comprises an automatic filling installation.
Apparatus (1,1') in accordance to claim 5, 6 or 7, characterized in that the apparatus comprises a level-indication on the tank indicating the level of the concentrated foam product.