WO2015076999A1

WO2015076999A1 - Foam dispenser with anti-clog features

Info

Publication number: WO2015076999A1
Application number: PCT/US2014/063024
Authority: WO
Inventors: Armin Arminak
Original assignee: Arminak & Associates, Llc
Priority date: 2013-11-25
Filing date: 2014-10-30
Publication date: 2015-05-28

Abstract

A mixing chamber for two fluid constituents is disclosed which provides improved mixing before the mixture is pushed through a mesh insert for the production of foam. Foam production using air and liquid is the basis of the exemplary embodiment though the disclosed mixing chamber could be used for any two fluid constituents. A single stream of air is diffused into a plurality of smaller streams of air. In the event a residual amount of foam is left behind such that it could dry out, improvement embodiments are disclosed in the form of anti- clog features.

Description

FOAM DISPENSER WITH ANTI-CLOG FEATURES

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of United States Provisional Patent Application Serial No. 61/908,366 filed November 25, 2013, which is hereby incorporated by reference.

BACKGROUND

Currently there are various dispensing devices which are constructed for handling a mixture of two fluid constituents. One example or category of such a dispensing device is a foam dispenser where the two fluid constituents are air and a liquid product, such as liquid soap. The production of foam requires a mixing of the air and the liquid product, and an initial mixing may occur prior to pushing those two constituents through a mesh or screen for bubble production by aeration. The quality of the produced foam is dependent in part on the degree or

thoroughness of the mixing of the two constituents. As used herein, the term "liquid" refers to the liquid product which is held or stored in some type of container or reservoir, whether positioned remotely or in close proximity to the location where the foam is dispensed. Although the liquid is liquid soap in the exemplary embodiment, other liquid products are contemplated such as hand sanitizes and household cleaning agents. Use of the term "product" includes the liquid state of the liquid product, and is used to describe a residual amount of foam left behind after a dispensing stroke. The issue addressed herein is how to remove this residual amount of foam before it dries out.

One consideration in the construction and arrangement of such dispensing devices is the manner in which the air and liquid flow through the dispensing device and which surfaces and/or flow orifices are contacted by any residual foam. The design aspect here is whether the charge of foam which is designed and desired for each dispensing stroke or cycle is completely dispensed. Typically, a small amount of the desired charge of foam remains inside of the device on one or more of the contacted surfaces and/or flow orifices. With regular use of the dispensing device, the next charge of air which is provided for foam production will normally remove any residual amount of foam left behind from the prior dispensing stroke or cycle. The focus here is on a residual amount of foam left behind in or on air flow orifices, passages and channels. In this repetitive removal process and considering the corresponding dispensing stroke which follows, another small amount of the produced charge of foam may remain in or on one or more of the contacted surfaces of the dispenser and/or air flow orifices, passages or channels.

When a second, subsequent dispensing stroke follows the immediately prior dispensing stroke, at least within a few hours, residual (foam) product from that prior dispensing stroke should still be in a "liquid" state to the degree that it is able to be removed by the new charge of air flowing via the air passages through the dispenser mechanism. However, when the time interval between two sequential dispensing strokes is extended to a few days, as one example or estimate, the exposure to air begins to dry out the residual foam product. If the time interval of non-use is of a sufficient length, depending on the type of product, the moisture content of the foam, and the amount of residual foam which is left behind, the air supply for the next foam production cycle and the next dispensing stroke may not be capable of removing that residual amount of dried foam. The longer the residual amount of foam is exposed to air, the more dried out it becomes. It is also envisioned that a further foam residue buildup may occur in or on surfaces and/or flow orifices within the mixing chamber portion of the dispensing device. Once again, the focus is on the air flow passages, channels, orifices, etc. If the prior residual amount of foam is not removed with the change of air for the subsequent dispensing stroke, that residual amount will form a first layer. The subsequent dispensing stroke will likely deposit its own fractional amount of residual foam on air flow passages. This additional amount of residual foam could also result in a dried out mass simply adding to the residual buildup. One concern is that air flow orifices and passages which are part of the mixing chamber construction will become at least partially clogged with foam residue as that liquid residue dries out due to its exposure to air. Partial clogging of air flow passages will likely adversely affect the quality and quantity of foam produced by the dispensing device. The disclosed embodiments of the present invention provide solutions to the issue of what may occur with infrequent use of this type of dispensing device.

SUMMARY

A mixing chamber for two fluid constituents is disclosed as part of a dispensing device and provides improved mixing before the mixture is pushed through a mesh insert for the production of foam. Foam production using air and liquid is the basis of the exemplary embodiment though the disclosed mixing chamber could be used for any two fluid constituents. The focus is on the air flow path and the possibility of a residual amount of foam being left behind and not delivered as part of that particular dispensing stroke. If the residual amount of foam dries out, it can clog or at least partially block air flow orifices, passages and channels and adversely affect foam production during a subsequent dispensing stroke.

In the exemplary embodiment, a single stream of air is diffused into a plurality of smaller streams of air. An air diffusing structure is used and is inserted into the air flow stream. When the single flow stream of air contacts the air diffusing structure, that single stream of air is separated and directed into a plurality of air channels which account for the plurality of smaller streams of air. A single stream of liquid is directed into an annular sleeve which defines a generally cylindrical cavity which extends around at least a portion of the air diffusing structure. This cavity configuration results in the creation of a thinner wall of liquid flow as compared to the larger or greater flow cross section of the entering liquid stream. This annular sleeve of a thinner wall of liquid flow surrounds the plurality of smaller streams of air.

In a second embodiment of the mixing chamber portion of the dispensing device, there are individual streams of liquid which are directed inwardly toward the individual streams of air. The mixing chamber construction disclosed can be used for any two fluid constituents, including those which might benefit from more thorough mixing.

The programmed charge of air and the programmed charge of liquid which are provided for each dispensing stroke are mixed and then injected or pushed through a mesh insert to produce foam. Ideally, the entirety of the charge of air and the entirety of the charge of liquid are used to produce foam. Likewise, ideally the entirety of the produced foam is actually dispensed to the user. However, the reality is that some small portion of the produced foam remains within and around the mixing chamber portion of the dispensing device. This residual amount of foam is able to migrate into contact with critical surfaces of the dispensing device. The reference herein to "critical surfaces" is directed to air flow orifices, passages and channels (herein collectively referred to as "air passages" and/or "air flow passages"). If this residual amount of foam dries out in an air flow orifice or on a similar air flow passage, something which may take a few days to occur, then the flow of air across this residual amount as part of the next foam production cycle and dispensing stroke will not be able to fully remove this prior residual amount of foam. If the residual amount of foam dries out on or in an air passage then the flow of air during the next dispensing stroke may be compromised. The thoroughness of the mixing can be affected. Further, if the amount of air for mixing is reduced without reducing the amount or proportion of liquid, then the dispensed foam could have a higher moisture content than desired.

Four exemplary embodiments are disclosed herein which address the issue of a residual amount of foam being left behind, being deposited on critical surfaces and then drying out on or in an air flow passage. To the extent or degree that this residual foam cannot be effectively removed by the action of the flow of air as part of the next foam production cycle, then the performance of the dispensing device can be compromised. One approach in terms of a solution to this problem is to design the mixing chamber in such a way as to essentially eliminate the deposit of a residual amount. As disclosed herein, the reference structure of one dispensing device includes an arrangement and orientation wherein the air flow direction into the mixing chamber is generally horizontal. One improvement approach rearranges the air flow direction to a generally vertical direction. This then allows gravity to act on the foam and if any residual amount of foam is left behind, it will likely be pulled out of any air passages due to the action of gravity.

Another approach to solving the residual foam issue is to lessen the likelihood that any residual amount of foam will adversely affect the air flow and air delivery of the next dispensing stroke. This can be achieved by enlarging the size of the air channels of the diffuser. With larger air channels, even if the full flow or cross-sectional area of a particular air channel is reduced slightly by a residual amount of dried out foam, there is still sufficient flow cross-sectional area left in order to handle the full charge of air intended to be delivered for mixing via that particular air channel, i.e. air flow passage.

Another approach is to design the mixing chamber such that the air delivery conduit is fitted with a one-way valve to close off the air supply between dispensing strokes. This construction limits the exposure of the residual amount of foam to drying air to only what is closed off within the mixing chamber. Once the charge of air is delivered for foam production, as part of one dispensing stroke, the air supply is closed off by the one-way valve. The exposure to air which is responsible for drying out the residual amount of foam is limited to the air which remains within the mixing chamber portion of the dispensing device. Reducing this volume of air is a design step which will limit the amount of air for drying the residual amount of foam. Limiting the amount of air may also reduce the rate of drying of the residual amount of foam.

Another approach is to first determine the time interval for the residual amount to begin to dry out. Then prior to the drying process being past the point of no return, sending a pulse resulting in a very small amount of air (and liquid) being sent to the mixing chamber, simply to blow out to the residual amount of foam which has been left in an air passage. The intent of the delivery of this small amount of air is to blow out the residual amount of foam before the next regular (i.e. full) dispensing stroke and before the residual amount of foam dries out.

Each exemplary embodiment of the present invention is described and illustrated herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one type of dispensing device which can utilize the mixing chamber constructions which are disclosed herein

FIG. 2 is a side elevational view of the FIG. 1 dispensing device.

FIG. 3 is a partial, top plan view of a first mixing chamber construction which is a part of the FIG. 1 dispensing device.

FIG. 4 is a diagrammatic view of the FIG. 3 mixing chamber.

FIG. 4A is a perspective view of an air diffuser used in the FIG. 3 mixing chamber.

FIG. 4B is a perspective view of an alternative air diffuser.

FIG. 4C is a perspective view of an alternative air diffuser.

FIG. 5 is a partial, top plan view of a second mixing chamber construction which may be used as a part of the FIG. 1 dispensing device.

FIG. 6 is a diagrammatic view of the FIG. 5 mixing chamber.

FIG. 6A is a perspective view of an air diffuser used in the FIG. 5 mixing chamber.

FIG. 7 is a front elevational view of a dispensing device according to another embodiment of the present invention.

FIG. 8 is a rear elevational view of the FIG. 7 dispensing device.

FIG. 9 is a top plan view of the FIG. 7 dispensing device.

FIG. 10 is a side elevational view, in full section, of the FIG. 7 dispensing device.

FIG. 11 is a front elevational view, in full section, of a mixing chamber comprising one portion of the FIG. 7 dispensing device.

FIG. 12 is a rear elevational view of the FIG. 11 mixing chamber.

FIG. 13 is a top plan view of the FIG. 11 mixing chamber.

FIG. 14 is a front elevational view of an air diffuser which comprises one portion of the FIG. 11 mixing chamber.

FIG. 15 is a side elevational view, in full section, of an alternative mixing chamber, according to the present invention. FIG. 16 is a front elevational view of an air valve casing which comprises one portion of the FIG. 15 mixing chamber.

FIG. 17 is a side elevational view, in full section, of the FIG. 16 air valve casing.

FIG. 18 is a side elevational view, in full section, of a connector which comprises one portion of the FIG. 15 mixing chamber.

FIG. 19 is a side elevational view of a valve member which comprises one portion of the FIG. 15 mixing chamber.

FIG. 20 is a perspective view of the FIG. 19 valve member.

FIG. 21 is a logic diagram directed to a method of use for a dispensing device according to another embodiment of the present invention.

DESCRIPTION OF THE SELECTED EMBODIMENTS

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates. One embodiment of the invention is shown in great detail, although it will be apparent to those skilled in the relevant art that some features that are not relevant to the present invention may not be shown for the sake of clarity.

In order to provide a reference construction for a dispensing device as background to the exemplary embodiments of the present invention, FIGS. 1-6A are provided. These reference drawings depict a dispensing device 20 with a two- constituent mixing chamber with a potential for the issues outlined herein to occur. More specifically, the disclosed structure may be susceptible to the deposit of a residual amount of foam and to the drying of that residual amount of foam due to exposure to air during a period of non-use of the dispensing device. The disclosed embodiments of the present invention address this issue and providing a reference construction for a dispensing device is believed to be helpful as part of a full understanding of the present invention.

Referring to FIGS. 1, 2 and 3, there is illustrated a dispensing device 20 which is disclosed in order to provide a reference structure for the embodiments of the present invention. Device 20 includes a liquid reservoir 22, pumping station 24, a liquid conduit 26, and air conduit 28, a mixing chamber 30 and a proximity sensor 32. In operation, once the dispensing device is properly packaged or housed and installed in the desired location, foam soap is dispensed into the hand of the user, once the presence of the user is sensed. While another substance or mixture can be produced and delivered, the exemplary embodiment of the reference structure focuses on a mixture of air and liquid soap for producing soap with a foam consistency. In this reference construction the flow paths are generally horizontal in actual use.

The pumping station 24 is constructed and arranged to generate a flow of air which travels via conduit 28 to mixing chamber 30. The pumping station is also constructed and arranged to draw a dose (or charge) of liquid, in the exemplary embodiment liquid soap, from the reservoir 22 and via conduit 26, deliver that does of liquid to the mixing chamber 30.

Referring now to FIGS. 4 and 4 A, the mixing chamber is constructed and arranged with an air inlet 34, a liquid inlet 36, a housing 38, an air diffuser 40 and a mesh insert 42. Sleeve 44 which defines the air inlet 34 receives the air diffuser

40. A portion of housing 38 connects the liquid inlet 36 with sleeve 44 so as to define a generally cylindrical cavity or space 46 surrounding sleeve 44. The details of air diffuser 40 are illustrated in FIG. 4A.

Air inlet 34 which is defined in part by sleeve 44 is generally cylindrical and is constructed and arranged for a close surrounding fit or arrangement relative to air diffuser 40. This close surrounding fit or arrangement may be achieved by a sliding fit which would be virtually line-to-line with air diffuser 40. However, even if slight clearance is left between sleeve 44 and air diffuser 40, this slight clearance does not constitute an adequate air flow pathway. Further, the air flow pathways of least resistance, due to size, are the defined air flow channels 62.

Sleeve 44 ends at approximately the juncture between the body 66 of the air diffuser 40 and its skirt 64.

In the exemplary embodiment of the reference structure the air inlet 34 and housing 38 are a unitary, integral component part. As such, housing extension 48 connects to housing 38 with a sliding fit. This interface needs to be sealed against leakage and this may be achieved by dimensioning the parts for a tight press fit or by the use of an adhesive or by ultrasonic welding.

One design variation which is contemplated for the reference structure is to make housing extension 48 and housing 38 a unitary, integral component part. This design approach results in redesigning the air inlet so that it would be received by or assembled onto (or into) a portion of housing 38. Housing extension 48 connects to housing 38 and in cooperation therewith defines mixing pocket 50 which is generally between the air diffuser 40 and the mesh insert 42. Housing extension 48 includes a shelf 52 which defines mixture opening 54 for passage of the air and liquid mixture from pocket 50 into the mesh insert 42.

In use, the mixing chamber 30 receives air via air inlet 34 and liquid via liquid inlet 36. Arrows 56 denote the air flow and arrows 58 denote the liquid flow. The air flows onto the conical top 60 of the air diffuser 40 and the four substantially equally-spaced channels 62 defined by the generally cylindrical body 66 of the air diffuser 40 (see FIG. 4A) create four smaller air flow streams extending or flowing axially in the direction of mixing pocket 50. While four air channels 62 are shown for the exemplary embodiment of the reference structure (i.e. dispensing device 20), a larger number is contemplated and while a smaller number of air channels can be used, the mixing would be expected to be less thorough. The base or skirt 64 of the air diffuser 40 includes an upper portion 64a which is shaped as a generally frustoconical form and a lower portion 64b which is generally cylindrical. The upper portion 64a defines the plurality of equally- spaced air channels 62a. Each air channel 62a is in flow communication with an aligned and corresponding one of air channels 62. The cooperating nature of air channel 62a results in each such channel receiving one air flow stream from a corresponding air channel 62 and thereafter directs its air flow stream radially outwardly. This outwardly directing of the air flow streams causes those air flow streams to travel into the sleeve of liquid which is flowing through cylindrical space 46. The intersection of these flows (air and liquid) creates initial mixing of the air and liquid. This mixing of air and liquid continues into mixing pocket 50. As illustrated, the air channels 62a break out through the outer surface of the generally cylindrical lower portion 64b.

The alternative diffuser 140 which is illustrated in FIG. 4B is similar to diffuser 40, but with a slightly different shaping. Diffuser 140 includes a conical top 160, a generally cylindrical body 166, air channels 162 defined by the body and a frustoconical skirt 164 defining air channels 162a. In comparing air diffuser 140 with air diffuser 40, it will be seen that a corresponding lower portion of a generally cylindrical shape is not included as a part of air diffuser 140.

A further design variation for the reference structure which is contemplated and illustrated in FIG. 4C is to have each air channel 262 of diffuser 240 end or be closed off at the juncture between the generally cylindrical body 266 of the diffuser 240 and skirt 264. Body 266 defines the four air channels 262 or whatever number of air channels one might select. By filling in or closing off any air channel portions in the skirt, the skirt 264 becomes a deflector for the air flow streams from air channels 262 rather than functioning as a director of those air flow streams.

The incoming stream of liquid enters the mixing chamber as a single stream and then spreads out into a generally cylindrical flow stream, essentially forming a sleeve of liquid flowing through cylindrical space 46 and surrounding the air flow. The single stream of incoming liquid is reshaped into a sleeve whose wall thickness is less or smaller when compared to the thickness of the incoming single flow stream. Then, when the individual streams of air deflect outwardly and intersect the sleeve of liquid, multiple mixing intersections and interactions occur at circumferentially spaced locations. By placing the air flow and its individual streams radially inside of the liquid flow which is rearranged into a generally cylindrical flow sleeve, the air and liquid mix at multiple sites and this mixing at multiple sites is an improvement as compared to mixing which is based on air flowing into a single stream of liquid which has a rod shape instead of a sleeve shape as provided by the disclosed embodiments of the reference structure.

Referring now to FIGS. 5, 6 and 6 A, another mixing chamber 70 is disclosed. Mixing chamber 70 is suitable for use with dispensing device 20 (i.e. the reference structure) and is intended to be represented by FIG. 5. The diagrammatic view of FIG. 6 and the air diffuser perspective view of FIG. 6A are similar to FIGS. 4 and 4A in some respects. Accordingly, the structural differences associated with mixing chamber 70 as compared to mixing chamber 30 will be described.

In the embodiment as represented by mixing chamber 70, the air inlet 72 is now configured with flow passages 74 so as allow liquid to flow radially inwardly toward the air diffuser 76. The housing extension 78 is constructed so as to close off any passageway or opening for the flow of liquid directly into the mixing pocket 80. Instead, with the lower end of the cylindrical space 82 closed off, all of the liquid must flow inwardly toward the outer surface of the diffuser 76 which is constructed with four liquid flow grooves 84 which are alternately arranged with the four air channels 86 which extend substantially the full length or height of the diffuser body 88 (see FIG. 6A). The liquid flow grooves 84 are not full height relative to body 88 as they each begin at approximately the location of the flow passages 74. The result of this flow pattern of air and liquid is to introduce eight separate flow streams into the mixing pocket 80. There are four flow streams of air alternating with four flow streams of liquid in a circumferential direction around the body of the air diffuser 76. This pattern of eight flow streams results in improved mixing of the two constituents within mixing pocket 80 before the mixture is pushed through the mesh insert 90.

As explained in the Background and Summary, with dispensing devices of the type generally illustrated in FIGS. 1-6 A, it is possible for a small amount of foam product to remain as a foam residue within the mixing chamber portion. As would be understood with this type of dispensing device there are various flow surfaces and various flow orifices and the sizes of these passages may be relatively small. The quality of the foam produced is dependent in part on the mixing of liquid product and air and having smaller flow streams can be advantageous in an improved foam quality. It is also desirable to try and dispense as much as possible of the foam product produced from a single cycle or charge rather than having some portion of that foam product left behind as residue. While this is clearly the preference, the reality is that some small amount of produced foam is left behind within the mixing chamber portion as a residue.

There are at least two related concerns with the possibility of a residual buildup of the foam product which is produced by the dispensing device. First, if the dispensing device is not used for several days after an immediately prior dispensing stroke, then the residual amount of foam product may dry out. If this residual amount dries out or at least dries to some extent, then it may not be removable during the next dispensing stroke as a result of air flowing across that residual amount. One concern is whether this residual amount of foam will adversely affect air flow and air delivery for the next dispensing stroke. Another concern is that over time additional residual amounts might accumulate and thereafter interfere with the air flow of subsequent dispensing strokes. There may be adverse performance consequences if critical air flow openings or passageways are partially clogged. One possible consequence is that the anticipated or designed amount of air for proper mixing with the quantity of liquid product will not be delivered. As a result, the foam quality may be adversely affected. For example, if the proportions of liquid product and air are shifted from those originally designed and additional liquid is provided due to reduced air, the foam may be too wet. The desired air flow pattern may also be affected resulting in less thorough mixing.

One solution to the issue of a residual amount of foam drying out on or in an air flow passage is to change the orientation of the mixing chamber and importantly to change the orientation of the air flow passages. The reference structure of dispensing device 20 as illustrated in FIGS. 1-3 is arranged and oriented for its intended use into what is best described as a generally horizontal position or configuration. The reference herein to generally or substantially "horizontal" refers to an earth reference and corresponds to what one would typically think of or assume as "horizontal".

Focusing on the air diffuser 40, the individual air channels 62 (i.e. air flow passages) are generally horizontal when dispensing device 20 is oriented as it would be for its intended use. In the reference structure 20 of FIG. 3, mixing chamber 30 is constructed and arranged such that the air diffuser 40 is oriented with it its length or longitudinal axis extending in a generally horizontal direction as illustrated. In this orientation, any residual foam which may migrate into one or more of the air passages 62 (i.e. air channels) of air diffuser 40 will not drain out of the one or more passages 62 due simply to gravity. A gravitational force still acts on the residual amount of foam, but any potential for downward travel of the residual amount simply draws some portion of that residual amount against a substantially horizontal retaining surface or length edge of the corresponding air passage 62. There is no opportunity for the residual amount of foam to actually drain out of the end of one or more air passages 62, due to gravity, when the diffuser 40 is oriented horizontally. The exemplary orientation of mixing chamber 30 wherein the air diffuser 40 is positioned in a generally vertical orientation was initially considered as simply one other construction option driven merely by the preferences of the designer. However, the orientation of the diffuser has taken on added importance when the issue of having a residual amount of foam left behind was recognized along with the realization that this residual amount of foam might dry out.

Therefore, while the initial consideration of a vertical or generally vertical orientation was simply as a design choice, it now has added significance in terms of allowing the action of a gravitational force or pull to help remove this residual amount of foam. The use of "vertical" herein will be understood as a direction which is substantially perpendicular to "horizontal".

This issue is further addressed by the orientation of dispensing device 300 as illustrated in FIGS. 7-13. Dispensing device 300 includes an outer housing 302, a dispensing mechanism 304, an air deliver system 306, a liquid delivery system 308 and a mixing chamber 310. Dispensing device 300 is constructed and arranged as a hands-free device such that upon activation of sensor 312, a charge of air and a charge of liquid are delivered by their corresponding delivery systems, to the mixing chamber 310. The charge of air is provided to the mixing chamber 310 by the air delivery system 306 in a metered or measured amount which has the desired mix ratio to the charge of liquid to be delivered so that foam of the desired consistency will be produced. The charge of liquid is provided to the mixing chamber 310 by the liquid delivery system 308. By using the same pump mechanism, as one option, activation of sensor 312 causes both delivery systems to provide their corresponding charge of constituent. Within the mixing chamber 310, the charge of air and the charge of liquid are mixed together and then directed through a mesh insert 314 and thereafter dispensed as foam, presumably into the hand(s) of the user.

Outwardly protruding portion 322 as an extension of the outer housing 302 is constructed and arranged to house the mixing chamber 310 and the component parts of the mixing chamber 310, including air diffuser 324. Portion 322 is specifically constructed and arranged so as to be able to position the air diffuser 324 in what is described as a generally vertical orientation. The frame of reference for terms such as "horizontal" and "vertical" as used herein is based on the assumption that the dispensing device 300 is stationed in an upright configuration such that its longitudinal axis 324a or centerline is substantially vertical. As with "horizontal" the term "vertical" is in reference to the normal use of that term relative to earth reference. This upright vertical configuration is the same whether the dispensing device 300 is mounted to or within another structure or is freestanding.

With this understanding, dispensing device 300 is configured in a generally vertical orientation and protruding portion 322 is configured in a generally horizontal orientation. Within protruding portion 322 is mixing chamber 310 and within the mixing chamber 310 is air diffuser 324. Air diffuser 324 has a longitudinal axis 324a or centerline which is substantially vertical. The air flow passages 62 (see FIG. 4 for example) are preferably constructed and arranged so as to be in alignment with the longitudinal axis 324a of the air diffuser 324. The portion of each air flow passage 62 which is around and defined by cylindrical body portion 324b is substantially parallel with the longitudinal axis 324a. Each air flow passage 62 is recessed relative to the outer surface (body portion 324b) of the air diffuser 324.

Positioning the air diffuser 324 in the illustrated and described orientation allows any residual amount of foam which might find its way into one or more of the air flow passages 62 to drain out of the one or more air flow passages 62 due to gravity. With this generally vertical orientation of the air diffuser and considering the manner in which the foam may migrate within the mixing chamber, it is less likely that foam will be able to reach the air flow passages 62 of the air diffuser 324 when that air diffuser is in the substantially vertical orientation. In order for the foam coming out of the lower end of the mesh insert 314 to reach the air diffuser 324, the foam must travel upwardly, against the gravitational pull.

Accordingly, the vertical orientation of the air diffuser 324 as compared and contrasted with a horizontal orientation, results in two improvements relative to the issue of a residual amount of foam being left behind and drying out on or in an air passage. One improvement is to make it less likely that foam will migrate

"upstream" to even reach the air diffuser 324. Secondly, if foam does reach the air diffuser 324, the lubricity of the foam product, combined with the gravitational pull, increases the likelihood that any residual amount of foam, or at least a majority of the residual amount, will drain out of the lower end of the one or more air passages. This embodiment of a dispensing device is directed to trying to prevent foam from blocking an air passage, by first preventing the foam from reaching the air diffuser and secondly by removing any foam from the air diffuser before it can dry out in or an air passage.

Another improvement embodiment directed to the residual foam concern as outlined and described herein is illustrated in FIG. 14. It is to be understood that the improvement represented by FIG. 14 is suitable for use whether the air diffuser 400 is positioned in a generally horizontal orientation or in a generally vertical orientation. This being said, it is likely that providing the FIG. 14 style of air diffuser 400 in the construction of dispensing device 300 will result in an improved structure. When air diffuser 400 is used in dispensing device 300, the design obtains the benefit of the vertical orientation as outlined above, and the benefit of having enlarged air flow passages 402 as part of (and defined by) air diffuser 400.

Air diffuser 400 has a construction which essentially the same as air diffuser 40 and air diffuser 324, except for the size and shape of the air passages 402 which are defined by the outer surface 404 of air diffuser 400. Consistent with the construction and arrangement of the other two air diffusers, air diffuser 400 includes a generally cylindrical body portion 406 and a frustoconical portion 408. Extending down the side of the body portion 406 and continuing into the frustoconical portion 408 are air passages 402 which are defined by the outer surface 404 of the air diffuser 400 and are generally equally spaced around the air diffuser 400. Only a single air passage 402 is illustrated in FIG. 14, but it is to be understood that preferably a plurality of equally-spaced air passages 402 will be present, typically 2, 3, 4, 5 or 6. One improvement which is realized by enlarging the air passages 402 of the air diffuser 400 is providing an air passage which is capable of delivering a full charge of air, even if part of the cross-sectional area of one or more air passages 402 is partially blocked by a residual amount of foam which is dried out in one or more of the air passages 402. In this regard, it is important to understand that a certain volume of air needs to pass through the air passages defined in part by the air diffuser so as to achieve the proper mix ratio with the charge of liquid being delivered. Each air flow passage which is longitudinal in nature has a transverse cross-sectional flow area. The cumulative cross-sectional flow area of all air flow passages provide sufficient volumetric flow for the desired charge of air to pass completely to the mixing location without any back flow, loss or other diversions. When the air flow passages are enlarged as described and illustrated herein, this enlarging of those air flow passages increases their lateral cross-sectional area. This increase in the cumulative cross-sectional area is in excess of what is required for the designed charge of air to flow to the mixing location. In turn, this means that if some small portion of one or more of those air flow passages are blocked (partially) by a small amount of residual foam which is now dried out, then that loss of cross-sectional area does not reduce the total cross-sectional area of all air flow passages to a value which is lower than the required area for adequate flow.

When air diffuser 400 is positioned in a generally vertical orientation, there is a type of symbiotic enhancement by adding the enlarged air passages in combination with the vertical orientation. This is explained as follows. When a residual amount of foam migrates into an air passage, the volume of foam relative to the cross-sectional size of the air passage may result in the foam blocking some portion of the air passage, whether entirely or only partially. With a relatively small air passage, in terms of its cross-sectional area, it is conceivable that the residual amount of foam may actually contact a majority if not the entirety of the inside surface of that particular air passage. Then as gravity works on the foam to facilitate the draining of the foam out of the air passage, the surface friction between the foam and the air passage has to be overcome. The greater the surface area of contact, the higher the surface friction. When the air passage is enlarged, as disclosed and illustrated herein, it is expected that there will be less surface area of contact with the foam and it is more likely that the gravitational force will be sufficient to drain the foam out of the air passage.

Another improvement embodiment directed to the residual foam concern is outlined and described herein is illustrated in FIGS. 15-20. This improvement is directed to limiting the exposure to air by any residual amount of foam which might be left behind in the mixing chamber. In order to illustrate this improvement embodiment, a representative mixing chamber 500 is illustrated in FIG. 15.

With further reference to FIG. 15, mixing chamber 500 includes an air input fitting 502 and a liquid input fitting 504. Each fitting 502, 504 is used to connect to a corresponding supply source for the corresponding constituent. Once these two constituents are introduced into mixing chamber 500, the initial mixing occurs, followed by the production of foam. Mixing chamber 500 further includes an air valve casing 506, valve member 508, connector 510, air diffuser 512, mesh insert 514, dispensing tip 516 and sleeve 518. These are each generally annular component parts. Valve member 508 operates in cooperation with air valve casing 506 in order to create an air valve for the mixing chamber. Further, mixing chamber 500 (see FIG. 15) is constructed and arranged such that the air diffuser 512 is positioned in a generally horizontal orientation. This orientation is selected to reinforce the understanding that the addition of air valve 508 should be sufficient to adequately address the residual foam issue, independently of incorporating any of the other improvement embodiments which are disclosed herein.

The improvement embodiment represented by FIGS. 15-20 is directed to limiting the volume of drying air to which the residual amount of foam is exposed. Without the use of the air valve (air valve casing 506 in combination with valve member 508), the interior of the mixing chamber remains open to the upstream air inlet 502 and the air source. An air pump is used to supply air to the mixing chamber. By remaining open to these upstream volumes of air, any residual amount of foam left in the interior of the mixing chamber 500 has a higher likelihood of drying out as there is more drying air available. By closing off these upstream air supplies, the residual amount of foam is exposed to less drying air.

An added benefit of adding an air valve (components 506 and 508) is that this air valve closes off any reverse flow (i.e. upstream) and/or any flow migration of any residual foam left in the mixing chamber 500. The air valve also closes off the upstream flow of any liquid into the air inlet passage. If any foam or liquid gets into any portion of the air inlet passage it might find its way into the air pump (not illustrated). Introducing foam or liquid into the air pump would adversely affect the performance of the air pump.

With continued reference to FIGS. 15-20 the air input fitting 502 is assembled into the air valve casing 506. The air valve casing 506 has a snap-fit assembly with connector 510. Interior panel 520 of air valve casing 506 includes an annular ring pattern of six air flow apertures 524. The center of this annular ring pattern includes a receiving hole 526. The valve member 508 is a unitary, elastomeric member and includes a generally circular cover 528 and a center stem 530. Center stem 530 has a snap-fit assembly into the receiving hole 526 of air valve casing 506. Once center stem 530 is secured into receiving hole 526, the upstream-facing surface 532 of cover 528 is pulled against the down-stream facing surface 534 of interior panel 520. The level of abutment force or the degree of engagement between surface 532 and surface 534 is such that air flow between these two engaging surfaces will not occur when the corresponding dispensing device is idle. The cover 528 has an outer edge periphery size which is larger than the outermost edge of each air flow aperture 524 such that the cover is effective in closing off any air flow through any of those flow apertures.

When the dispensing device is operated, the flow of air into the mixing chamber is achieved by using air pressure to deflect (raise) an edge portion of cover 528 away from surface 534 and thereby uncover (at least partially) one or more of the air flow apertures. When an edge portion of the cover is deflected or pushed away from surface 534 due to incoming air flow, a portion of at least one air flow aperture 524 is uncovered and this then allows air from the air pump to flow into the mixing chamber 500. This air flow is from the air pump via air input fitting 502 and from there past the air valve and into the mixing chamber for mixing with liquid and thereby the production of foam.

Cover 528, as an elastomeric component, resiliently returns into sealing contact against surface 534 and closes over the apertures 524 when the air pressure due to air flow from the air pump or other source is removed. As one of ordinary skill would appreciate, there needs to be a minimum of threshold air pressure which is sufficient to deflect the cover 528 out of sealing contact or engagement. Once the air flow is allowed into the mixing chamber 500, the air moves to the air diffuser 512 and mixes with the liquid. This air and liquid mixture is then pushed through the mesh insert 514. The foam output of the flow through the mesh insert 514 travels to the dispensing tip 516 where it is made available to the user.

Once the input charge of air has been delivered into the mixing chamber, the cover 528 closes and this limits the volume of air which might be seen by any residual amount of foam. By reducing the volume of drying air, the likelihood of the residual amount of foam drying out is reduced. The rate of drying out is also reduced. Accordingly, the next charge of air might be delivered before the residual amount of foam dries out enabling this next charge of air to blow out this residual amount of foam from within the mixing chamber 500.

With the cover 528 closed against surface 534, any foam or liquid left within the mixing chamber 500 is unable to flow upstream through the air passage whereby it might otherwise reach the air pump and adversely affect the operation of the air pump.

The improvement embodiment of FIGS. 15-20 may additionally

incorporate the improvement embodiment of FIG. 14 (enlarged air passages defined by the air diffuser). Still further, the orientation of the FIG. 15 mixing chamber may be generally horizontal, as illustrated, or generally vertical as an option, consistent with the teachings of the improvement embodiment of FIGS. 7- 13. All three of these improvement embodiments can be integrated in combination as there is no structural conflict nor any performance conflict between these three improvement embodiments and these three improvement embodiments are not considered to be mutually exclusive.

Another improvement embodiment directed to the issue of residual foam is illustrated in the flow diagram of system 600 of FIG. 21. This flow system 600 represents part of the electronic "intelligence" and a specific operational procedure (i.e. procedural steps) which is part of a representative hands-free dispensing device which is suitable for use with a dispensing device as disclosed herein.

The beginning step 602 of system 600 is startup, followed by an initializing step 604. These two steps set up system 600 for its intended operation. System 600 is intended for use as part of a hands-free dispensing device and there is a decision step 606 regarding whether or not the infrared (IR) sensor beam is broken. What is being accomplished by system 600 is a selective pulsing of the air and liquid for a short duration to use air to blow out any residual amount of foam left behind on or in one or more air passages of the air diffuser, after the last foam dispensing stroke or cycle has concluded. Accordingly, the first decision step 600 wants to determine if the IR beam is broken. If the IR beam is not broken, it should mean that the prior dispensing stroke has been initiated and the hands of the user have been with drawn from the proximity of the dispensing device. This should mean that foam soap has been dispensed and the user is washing the hands before rinsing. At decision step 606, if the beam is still broken, then we move to step 608 which institutes a 5-second interval and then returns to the start of step

606. During the 5-second interval, an LED signal light flashes as a way to indicate that the user is still interfacing with the dispensing device. This loop of 606 to step 608 and back to step 606 is repetitive until the IR beam is no longer broken. At this point, a "NO" response to step 606 results in moving to step 610. At step 610 the LED lights up for 3 seconds as a way to confirm that the system 600 is going into a sleep or idle mode at 612. The next decision point at 614 queries for how long has the dispensing device been idle. This step is programmable for a desired time interval (the duration of the idle status). In the exemplary embodiment it has been determined that the residual amount of foam is likely to dry out in

approximately 96 hours. After this time interval of non-use, it is anticipated that the residual foam will dry out such that the air delivery of the next cycle will not be able to blow out this residual amount of foam from within the air diffuser air passages or from within other portions of the mixing chamber. Depending on the type and composition of the liquid and depending on how "wet" the foam might be, the foam drying out time interval of 96 hours could be longer or shorter, and for this reason, that time interval needs to be selectively programmable.

At decision step 614, the query is the length of idle time since the last dispensing cycle compared to the time interval which has been programmed into that decision step. If, in the exemplary embodiment, the actual idle time interval is less than 96 hours, then the process goes to step 616 and checks to see if the IR beam is broken. If the IR beam is broken then the system proceeds to step 618 for normal dispensing. This activates the delivery of air and liquid for 1.2 seconds at step 618. If the idle duration is at least 96 hours, then a "cleaning" pulse of air and liquid of 0.2 seconds duration is produced at step 620. This brief pulse provides a small charge of air directed into the mixing chamber and specifically directed into the air passages of the air diffuser for blowing out any residual amount of foam which has not yet dried to the point that a brief pulse or charge of air would be ineffective. The focus here is on residual foam which is on or near one or more of the air passages of the diffuser. Residual foam which may dry out on or in one or more of those diffuser air passages could adversely affect the desired air delivery of the subsequent delivery stroke. After step 620 is performed, the timing interval is reset back to zero at step 622 in order to resume the time count up to 96 hours. As indicated, the selection of 96 hours is for the exemplary embodiment as the specific time interval may depend on a variety of factors and is thus both selective and programmable.

Subsequent to dispensing step 618 there is a voltage check loop for battery power beginning with decision step 624 with regard to resetting the dispensing device for the next dispensing stroke. The voltage check loop first queries whether the dispensing device voltage is below 4.7 volts. If the voltage is 4.7 volts or higher, the system goes to step 626 and from there checks the status of the IR beam at step 628. Step 628 queries whether or not the IR beam is broken. If the beam is broken, the system keeps checking (at step 630) every 5 seconds until the hand or hands of the user are withdrawn from the IR beam. If the IR beam is not broken, the system resets back to the juncture between step 610 and 612.

Going back to step 624, if the voltage is below 4.7 volts, then at step 632 there is a query to see if the system voltage is below 4.2 volts. If the system voltage is below 4.2 volts, then the system shuts down at step 634. If the voltage is at least 4.2 volts, then at step 636 there is a low voltage warning by means of a 15- second illumination of the LED. This 15 -second LED illumination occurs after each dispensing stroke (i.e. actuation). Following step 636, the system continues with step 626.

System 600 may be used independently of any of the other improvement embodiments disclosed herein as well as used in combination with one or more of any of these other improvement embodiments. As noted, these improvement embodiments are not mutually exclusive of one another. These various

improvement embodiments address, in a novel and unobvious manner, the concern over a residual amount of foam drying out in or on one or more of the air passages.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes, equivalents, and modifications that come within the spirit of the inventions defined by following claims are desired to be protected. All publications, patents, and patent applications cited in this specification are herein incorporated by reference as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated by reference and set forth in its entirety herein.

Claims

1. A mixing chamber for air and liquid for the production of foam, said mixing chamber comprising:

a first flow inlet for air;

an air diffuser positioned downstream from said first flow inlet for dividing an incoming air flow into a plurality of air flow streams;

a second flow inlet for liquid;

a mixing pocket constructed and arranged for receipt of air and liquid; and an air valve positioned between said first flow inlet and said air diffuser.

2. The mixing chamber of claim 1 wherein said air valve includes a valve casing and a valve member.

3. The mixing chamber of claim 2 wherein said valve casing defines an air flow opening.

4. The mixing chamber of claim 3 wherein said valve member includes a stem and a sealing portion.

5. The mixing chamber of claim 4 wherein said stem is received by said valve casing such that said sealing portion closes off said air flow opening.

6. The mixing chamber of claim 5 wherein said valve member is an elastomeric, unitary component.

7. The mixing chamber of claim 1 wherein said air diffuser includes a longitudinal centerline and is positioned such that the longitudinal centerline is substantially vertical.

8. A hands-free dispensing device for delivery of a foam composition, said hands-free dispensing device comprising:

an air delivery system; a liquid delivery system;

a mixing chamber constructed and arranged in flow communication with said air delivery system and in flow communication with said liquid delivery system;

means for producing a foam composition from a mixture of air and liquid, said air being supplied by said air delivery system and said liquid being supplied by said liquid delivery system; and

an anti-clog control system integrated with said air delivery system for producing a pulse of air for removal of residual foam.

9. The hands-free dispensing device of claim 8 which further includes an air diffuser which is positioned in said mixing chamber, said air diffuser defining an air flow passage.

10. The hands-free dispensing device of claim 9 wherein said residual foam is left behind in said air flow passage and said pulse of air is directed through said air flow passage.

11. An anti-clog control system for use with a foam dispensing device which includes an air delivery system, a liquid delivery system, a mixing chamber, means for producing foam and an air diffuser included in the mixing chamber, said anti-clog control system comprising:

means for setting a target value for an interval of non-use of the foam dispensing device;

means for checking the interval of non-use of the foam dispensing device; and

means for sending a pulse of air via said air delivery system to said mixing chamber when the interval of non-use exceeds the target value.

12. The anti-clog control system of claim 11 wherein said target value is approximately 96 hours.

13. The anti-clog control system of claim 11 wherein said pulse of air has a pulse duration of approximately 0.2 seconds.

14. The anti-clog control system of claim 11 which further includes means for checking a battery voltage status.

15. A dispensing device for delivery of a foam composition, said dispensing device comprising:

an air delivery system;

a liquid delivery system;

an air diffuser positioned in said mixing chamber, said air diffuser defining an air passage wherein said air diffuser has a longitudinal centerline and said air diffuser is positioned within said mixing chamber such that said longitudinal centerline is in a substantially vertical orientation to facilitate the draining of any residual form which may be left in said air passage.

16. The dispensing device of claim 15 wherein said air diffuser defines a plurality of air passages.

17. The dispensing device of claim 16 wherein each air passage of said plurality of air passages is longitudinal and extends along an outer surface of said air diffuser.

18. The dispensing device of claim 15 wherein said mixing chamber in cooperation with said air diffuser defines a longitudinal air flow path between said air delivery system and said means for producing a foam composition.

19. The air diffuser of claim 18 wherein said any residual foam is produced by said means for producing a foam composition and is not dispensed to a user as a part of the same dispensing stroke producing the foam composition.

20. The dispensing device of claim 15 which further includes an air valve positioned upstream from said air diffuser to limit the volume of air to which the residual foam is exposed.

21. A mixing chamber for two fluid constituents comprising:

a first flow passage for a first fluid constituent;

a diffuser with a longitudinal centerline is positioned in said first flow passage for dividing flow of said first fluid constituent into a plurality of flow streams;

a second flow passage for a second fluid constituent;

a sleeve surrounding said diffuser, said sleeve being in flow communication with said second flow passage for a flow of said second fluid constituent to be arranged in a flow pattern which surrounds said diffuser; and

a mixing pocket constructed and arranged for receiving said two fluid constituent flows, wherein the diffuser is positioned such that its longitudinal centerline is substantially vertical.

22. The mixing chamber of claim 21 wherein said diffuser is used for managing the flow of air and is constructed and arranged with a plurality of longitudinal air passages whose combined lateral cross-sectional flow area is in excess of a calculated cross-sectional flow area based on the amount of liquid to be mixed for foam.

23. The mixing chamber of claim 22 wherein each air passage is defined by and extends along an outer surface of said air diffuser.

24. The mixing chamber of claim 22 which further includes an air valve positioned between said first flow inlet and said air diffuser.