WO2009142886A1

WO2009142886A1 - Foam dispenser with compressible porous mixing element

Info

Publication number: WO2009142886A1
Application number: PCT/US2009/042314
Authority: WO
Inventors: Nick Ciavarella; David Hayes
Original assignee: Gojo Industries, Inc.
Priority date: 2008-05-23
Filing date: 2009-04-30
Publication date: 2009-11-26

Abstract

A foam pump (14) includes a mixing chamber (48) retaining a foamable liquid and being collapsible from an expanded volume to a contracted volume upon actuation of the foam pump (14). A dispensing tube (54) includes an inlet (51) positioned in said mixing chamber (48), and a compressible porous mixing element (64) is positioned in the mixing chamber (48), with the compressible porous mixing element (64) retaining foamable liquid and air. Upon actuation of the foam pump (14), the volume of the mixing chamber (48) is progressively- collapsed from said expanded volume toward said contracted volume, and said compressible porous mixing element (64) is thereby progressively compressed so that foamable liquid and air in said compressible porous mixing element (64) are mixed, creating a foam product that is fed through said inlet (51) of said dispensing tube (54) and into said dispensing tube (54).

Description

FOAM DISPENSER WITH COMPRESSIBLE POROUS MIXING ELEMENT

FIELD OF THE INVENTION

[0001] The present invention generally relates to a foam pump wherein air and a foamable liquid are mixed to create a foam product. This invention also relates to a refill unit including the foam pump associated with a container providing the foamable liquid, the refill unit being a disposable and replaceable unit for receipt in a dispenser housing.

BACKGROUND OF THE INVENTION

[0002] Foam pumps typically include an air pump portion and a fluid pump portion — the two requiring communication to ultimately create the foam product. Such pumps have been provided through various types of pump structures, as known by those familiar with the foam pump arts. Regardless of structure, the foam pumps dispense the foam product when both the air pump portion and the fluid pump portion are actuated through movement of a simultaneously actuated member. In many of the prior art structures, both the air pump portion and the fluid pump portion must be fully actuated to ensure that a quality foam product is produced. If the foam pump and fluid pump portions are not fully actuated, the foam quality may be compromised, due to the fact that a less-than-complete actuation can result in a different air-to-foamable liquid mixing ratio. Thus, the art would benefit from a foam pump wherein a less-than-complete actuation still results in a quality foam product being dispensed.

[0003] In wall-mounted foam product dispensers, the foam pump is typically carried on a refill unit, which includes a container of foamable liquid with the foam pump secured thereto. The refill unit is inserted in a dispenser housing, which provides a push bar or other actuation member for actuating the foam pump. The refill unit is disposed of when empty, and replaced with a new refill unit with a new supply of foamable liquid. The less-than-complete actuation mentioned above typically occurs when a user does not fully depress the push bar or other actuation member. To those knowledgeable in the art, this is known as "short stroking" the dispenser, and, as already mentioned, it can lead to the dispensing of a foam product of poor quality. Thus, a need also exists in the art for a refill unit carrying a foam pump that exhibits improved performance during a short stroke dispensing. [0004] In prior art foam pumps, the air and liquid that are mixing to produce the foam are typically forced through one or more mesh screens to homogenize the air/liquid mixture into a quality foam product. However, those screens cost money and are labor intensive to secure within the pump mechanisms. Therefore, the art would also benefit from a foam pump wherein such mesh screens are not required.

SUMMARY OF THE INVENTION

[0005] In accordance with an embodiment of this invention, a foam pump is provided. The foam pump includes a mixing chamber retaining a foamable liquid and being collapsible from an expanded volume to a contracted volume upon actuation of the foam pump. A dispensing tube includes an inlet positioned in said mixing chamber, and a compressible porous mixing element is positioned in the mixing chamber, with the compressible porous mixing element retaining foamable liquid and air. Upon actuation of the foam pump, the volume of the mixing chamber is progressively collapsed from said expanded volume toward said contracted volume, and said compressible porous mixing element is thereby progressively compressed so that foamable liquid and air in said compressible porous mixing element are mixed, creating a foam product that is fed through said inlet of said dispensing tube and into said dispensing tube.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Fig. 1 is a cross sectional view of a refill unit in accordance with the present invention, shown with the pump thereof in a non-actuated rest position; [0007] Fig. 2 is a cross sectional view of the refill unit of Fig. 1, but shown as the pump thereof is initially actuated;

[0008] Fig. 3 is a cross sectional view of the refill unit, shown with the pump thereof more fully actuated; [0009] Fig. 4 is a cross sectional view of the refill unit, shown with the pump fully actuated; and

[0010] Fig. 5 is a perspective view of a piston assembly of the pump.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS [0011] With reference to Fig. 1 it can be seen that a refill unit in accordance with this invention is shown and designated by the numeral 10. The refill unit is shown is cross section, and, in accordance with preferred embodiments, is generally cylindrical, as connoted by its threaded engagement with the neck of a container. It should be appreciated that the refill unit may deviate from a generally cylindrical design inasmuch as it will operate as disclosed without a specific cylindrical structure. The refill unit 10 includes a container 12, which holds a foamable liquid S for dispensing. The refill unit 10 also includes a foam pump 14 having a cap 16 that mates with the container 12 through the interaction of cap threads 18 with container threads 20. Other means for securing the foam pump 14 to the container 12 can be employed. [0012] The cap 16 provides a source plate 22 that covers the open end 23 of the container 12, and provides a liquid source passage 24 having an inlet 26 communicating with the foamable liquid S in the container 12, and an outlet 28, communicating with a liquid feed chamber 30, which will be discussed more fully below.

[0013] A piston housing 32, which is defined by at least one sidewall 34, extends from the cap 16, steps outwardly at step 36, and extends on to provide an open distal end 38. A feed plate 40 is secured in the piston housing 32, proximate the step 36. The feed plate 40 is secured to the interior of the piston housing 32 through a snap fit connection 42, which can visually be appreciated in the drawing as a mating groove and protrusion, the groove being provided in the sidewall 34, and the protrusion being provided by a feed plate 40. The feed plate 40 is also stabilized by extending over the step 36, though it should be appreciated that the present invention is not to be limited to or by any particular piston housing shape or feed plate connection. [0014] The feed plate 40 provides a shuttle passage 44, which is aligned with the liquid source passage 24, and provides liquid feed apertures 46, spaced outwardly from the shuttle passage 44. The liquid feed chamber 30 is defined between the source plate 22, the feed plate 40 and the sidewall 34. The feed plate 40 also defines one boundary of a mixing chamber 48, the other boundaries being provided by the sidewall 34 and a piston assembly 50.

[0015] The piston assembly 50 includes a piston plate 52, and a dispensing tube 54 that extends through the piston plate 52 from an inlet 51 inside the mixing chamber 48 to an outlet 53 outside the mixing chamber 48. In this particular embodiment, the dispensing tube 54 is formed as part of the piston plate 52, such that the dispensing tube 54 moves with the piston plate 52. The dispensing tube 54 is aligned with the liquid source passage 24 and the shuttle passage 44 such that it can mate with a shuttle piston 56 that extends through both the liquid source passage 24 and the shuttle passage 44. The shuttle piston 56 mates with the dispensing tube 54 at dispensing end 57, through a snap fit connection 55. With this construction, the shuttle piston 56 also moves with the piston plate 52. The piston plate 52 is sealed to the sidewall 34 at a wiper seal 58, and is biased to the non-actuated rest position of Fig. 1 by any suitable biasing mechanism, which is here shown as a spring 60. The piston plate 52 is retained in the mixing chamber 48 by a rib 62 proximate open end 38. If desired, the dispensing tube 54 could be made stationary with an appropriate wiper seal between the piston plate 52 and the dispensing tube 54 and with appropriate connection between piston plate 52 and shuttle piston 56. [0016] A compressible porous mixing element 64 is provided in the mixing chamber 48, and is preferably sized to extend from the feed plate 40 to the piston plate 52 to surround those portions of the shuttle piston 56 and the dispensing tube 54 that reside within the mixing chamber 48. The compressible porous mixing element 64 is also sized such that it is positioned inwardly of the liquid feed apertures 46. The piston plate 52 provides a ramped surface 66 extending to a seat surface 68, where the compressible porous mixing element 64 is received and held at the bend 69. In some embodiments, the compressible porous mixing element 64 is sufficiently resilient such that the spring 60 is not necessary, i.e., the compressible porous mixing element 64 would provide the biasing force necessary to cause the piston assembly 50 to be held at the non-actuated position of Fig. 1.

[0017] Although other materials will be found to be suitable, and the recitation of particular materials herein is not to be considered to limit this invention, it has been found that the foam pump of this invention can be actuated to yield a high quality foam product by employing a sponge as the compressible porous mixing element 64. In a particular embodiment, the compressible porous mixing element 64 is an open cell polyurethane, thermoplastic or rubber sponge element. In yet other embodiments, the compressible porous mixing element 64 is a thermally reticulated open cell polyurethane, thermoplastic or rubber foam sponge element. In accordance with particular embodiments, such open cell foam sponge elements are employed having a cell count of from 50 to 100 parts per square inch, in other embodiments, from 60 to 90 parts per square inch, and in other embodiments, from 70 to 80 parts per square inch. In particular embodiments, these open cell foam sponge elements have a density of from 1.2 to 2.8 pounds per cubic foot, in other embodiments, from 1.5 to 2.5 lbs/cubic foot, and in other embodiments, from 1.8 to 2.2 lbs/cubic foot. [0018] The shuttle piston 56 forms a source valve 70 at a source end 72 positioned inside the volume of the container 12 (the interior side of the cap 16). More particularly, the cap 16 provides a valve seat 74 proximate the liquid source passage 24, and the source end 72 of the shuttle piston 56 provides a complimentary valve seat 75 that, in the rest position of Fig. 1, is pulled downwardly to seal against valve seat 74. The shaft 76 of the shuttle piston 56 is smaller than the liquid source passage 24 so that the foamable liquid S can pass from the interior of container 12 to the liquid feed chamber 30 when the seal between valve seat 74 and valve seat 75 is broken. A shuttle valve 78 surrounds the shaft 76 and is positioned in the liquid feed chamber 30. The shuttle valve 78 is held on the shaft 76 through friction, such that it moves with the shaft 76, though its movement is limited by contact with the source plate 22 and the liquid feed plate 40. More particularly, the frictional fit between the shuttle valve 78 and the shaft 76 is such that, when the shuttle piston 56 is moved upwardly and the shuttle valve 78 contacts the source plate 22, the shuttle piston 56 may continue to move upwardly, with the shaft 76 sliding through the shuttle valve 78. Similarly, when the shuttle piston 56 moves downwardly and the shuttle valve 78 contacts the feed plate 40, the shaft 76 may slide through the shuttle valve 78, permitting the shuttle piston 56 to continue to move downwardly. [0019] With the general structure of the refill unit 10 having been disclosed above, the actuation of the foam pump 14 is now described. The non-actuated rest position is shown in Fig. 1. To actuate the foam pump 14, the piston assembly 50 is moved upwardly toward the feed plate 40. Because the shuttle piston 56 is secured to the piston assembly 50, it moves with the piston assembly 50, and the source valve 70 opens when valve seat 75 is removed from valve seat 74. This opens the liquid source passage 24, as seen in Fig. 2, permitting some foamable liquid S to pass from the container 12 into the liquid feed chamber 30 under gravity, as seen at arrows A. Foamable liquid S will be fed into the liquid feed chamber 30 until such time as the shuttle valve 78 contacts the source plate 22 and closes off the liquid source passage 24, as seen in Fig. 3. The foamable liquid S in the liquid feed chamber 30 can advance to the mixing chamber 48 through the liquid feed apertures 46, and foamble liquid S within the mixing chamber 48 is urged into and through the compressible porous mixing element 64, as the volume of the mixing chamber 48 decreases with the advancement of the piston assembly 50 toward the feed plate 40. [0020] After the shuttle valve 78 closes off the liquid source passage 24, the piston assembly 50 may still be advanced further upward toward the feed plate 40, as seen in Fig. 4, wherein the foam pump 14 has been fully actuated. In this position, the mixing chamber 48 is fully collapsed, and much of its content has been forced through the compressible porous mixing element 64, through inlet 51, into dispensing tube 54, and out at outlet 53. This is generally represented by arrows B in Figs. 2-4. As seen in the perspective view of the piston plate 52, shown in Fig. 5, the contents of the mixing chamber 48 can enter the dispensing tube 54 through inlets 51, which are formed at multiple positions around the sidewall 80. [0021] From this fully actuated position, the force moving the piston assembly 50 toward the feed plate 40 is removed (for example, by release of a dispenser push bar after an actuation/dispensing stroke), and the piston assembly 50 begins to move back toward the rest position of Fig. 1. During the return stroke, the shuttle valve 78 moves with the shuttle piston 56 such that the liquid source passage 24 is open until the valve seats 74 and 75 meet. This is similar to the opening shown in Fig. 2 during movement toward the fully actuated position. Thus, an additional amount of the foamable liquid S is charged into the liquid feed chamber 30. As this is occurring, the mf. ipg chamber 48 is also exp|nding,%ή^ this djiaws a vacuum up through outtβj|53 andjrffie

piil|j!g air Jcom the

and fchrbugh the^*fόmprφtsϊble porous mixiiig ^'"elemfrft 6441& «#0 thl mixing|clbιamber>^!48. This suction offair wijl benefidaUyJllear tjje dispensing tubj?54 of respiial liquidxand foam, Wiich _xffili prej|ent drippirigfbf product fcgm outl%t|53. Because the shuttle valve 78 quickly reciprocates between blocking the shuttle passage 44 and the liquid source passage 24, only a small amount of liquid is fed from the container 12 during the reciprocal movement of the piston assembly 50. Because the mixing chamber 48 is recharged with a quantity of air upon the expansion of the mixing chamber 48, there is a mixture of both air and foamable liquid S in the mixing chamber 48. As a result, upon actuation, both air and foamable liquid S are fed through the compressible porous mixing element 64, and a foam product is created and forced through the dispensing tube 54. The foaming action is similar to the lathering of a sponge element when squeezed with a soap solution impregnated therein.

[0022] It has been found that this design significantly eliminates the problems associated with short stroking a dispenser. More particularly, the refill unit 10 can be received in a typical wall-mounted dispenser housing, and can be appropriately associated with a push bar of the dispenser housing so that pushing the push bar causes the pump 14 to be actuated. In such a combination, the push bar of the dispenser does not have to be fully pressed in order to ensure that a suitable foam product is dispensed. This results from the fact that the compressible porous mixing element 64 creates a foam, when impregnated with a foamable liquid and squeezed. The creation of the foam product does not depend upon the extrusion of a porous liquid and air mixture through a mesh screen element, as in the prior art. Indeed, in an embodiment of this invention, there is an absence of such a screen element, though one might be used, if desired, in other embodiments.

[0023] In light of the foregoing, it should be apparent that the present invention provides a foam pump, refill unit and dispenser that substantially improve the art. While only particular embodiments have been described in detail hereinabove, it would be appreciated that the present invention is not necessarily limited to or by any particular embodiments so disclosed. The attached claims will serve to define the invention.

Claims

CLAIMSWhat is claimed is:

1. A foam pump comprising: a mixing chamber retaining a foamable liquid and being collapsible from an expanded volume to a contracted volume upon actuation of the foam pump; a dispensing tube including an inlet positioned in said mixing chamber; and a compressible porous mixing element positioned in said mixing chamber, said compressible porous mixing element retaining foamable liquid and air, wherein, upon actuation of the foam pump, the volume of the mixing chamber is progressively collapsed from said expanded volume toward said contracted volume, and said compressible porous mixing element is thereby progressively compressed so that foamable liquid and air in said compressible porous mixing element are mixed, creating a foam product that is fed through said inlet of said dispensing tube and into said dispensing tube.

2. The foam pump of claim 1, wherein said mixing chamber is defined by a piston housing and a piston plate received in the piston housing and adapted to reciprocate between a rest position and an actuated position, the movement of said piston plate from said rest position to said actuated position causing said mixing chamber to collapse and said compressible porous mixing element to compress.

3. The foam pump of claim 2, wherein said dispensing tube extends through said piston plate to provide an outlet outside of said mixing chamber.

4. The foam pump of claim 3, wherein said compressible porous mixing element surrounds said inlet of said dispensing tube.

5. The foam pump of claim 4, wherein said mixing chamber is further defined by a liquid feed plate opposed to said piston plate such that said piston plate is moved toward said liquid feed plate as it is moved from its rest position to its actuated position.

6. The foam pump of claim 5, wherein said compressible porous mixing element extends from contact with said liquid feed plate to contact with said piston plate, such that, as said piston plate is moved from its rest position to its actuated position, said compressible porous mixing element is squeezed between said liquid feed plate and said piston plate.

7. The foam pump of claim 2, further comprising: a liquid feed plate opposed to said piston plate such that said piston plate is moved toward said liquid feed plate as it is moved from its rest position to its actuated position, said liquid feed plate further defining said mixing chamber; a source of foamable liquid; a source plate including a liquid source passage communicating with said source of foamable liquid; and a liquid feed chamber defined between said source plate and said liquid feed plate, said liquid feed chamber receiving foamable liquid from said source of foamable liquid, through said liquid source passage.

8. The foam pump of claim 7, further comprising: a shuttle piston having a shaft and a valve seat, said shaft extending through said liquid source passage in said source plate and though a shuttle passage in said liquid feed plate, said shaft being operatively associated with said piston plate to move therewith, said valve seat closing said liquid source passage when said piston plate is in said rest position and opening said liquid source passage when said piston is moved toward said actuated position; a shuttle valve retained on said shaft to move therewith, said shuttle valve being capable of moving relative to said shaft, wherein the movement of said shuttle valve with said shaft is limited by its contact with said liquid feed plate and said source plate.