DIAPHRAGM FOAM PUMP FOR FOAM DISPENSERS AND REFILL UNITS
A refill unit for a foam dispenser including a liquid container and a diaphragm foam pump connected to the liquid container and diaphragm foam pumps. The diaphragm foam pump includes an elastomeric diaphragm having an air piston bore and a bellows. The air piston bore forms at least a portion of an air chamber. A reservoir is located at least partially within the bellows that includes a liquid inlet. The diaphragm foam pump includes a piston that forms a portion of the air chamber wherein the piston bore may be moved relative to the piston. Movement in a first direction causes air in an air chamber to be compressed and draws liquid into the reservoir and further movement in the same direction causes compressed air to flow into the reservoir where it mixes with the liquid and is expelled as a foam.
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The present invention relates generally to foam pumps and more particularly to diaphragm foam pumps for a foam dispensing system and refill units for the same.
BACKGROUND OF THE INVENTIONLiquid dispensers, such as liquid soap and sanitizer dispensers, provide a user with a predetermined amount of liquid upon the actuation of the dispenser. It is sometimes desirable to dispense the liquids in the form of foam by, for example, injecting air into the liquid to create a foamy mixture of liquid and air bubbles. Many prior art foam pumps have many parts which add to the complexity and cost of the pump.
SUMMARYA refill unit for a foam dispenser including a liquid container and a diaphragm foam pump connected to the liquid container is disclosed herein. The diaphragm foam pump includes an elastomeric diaphragm having an air piston bore portion and a bellows portion. The air piston bore portion forms at least a portion of an air chamber. In addition, a reservoir is located at least partially within the bellows. The reservoir includes a liquid inlet. In addition, the diaphragm foam pump includes a piston that forms at least a portion of the air chamber. The piston bore may be moved relative to the piston. Movement of the air piston bore portion in a first direction causes air in the air chamber to be compressed and draws liquid into the reservoir and further movement of the air piston bore in the same direction causes compressed air to be released from the air chamber and to flow into the reservoir where it mixes with the liquid and is expelled as a foam.
A plurality of diaphragm foam pumps are disclosed herein. In one embodiment, a diaphragm foam pump includes an elastomeric diaphragm having an air piston bore portion and a bellows portion. The air piston bore portion is located at least partially within the bellows portion. A reservoir is located within the bellows. The reservoir includes a liquid inlet and an air inlet. A piston post is also included and the piston bore moves relative to the piston post to compress air. Movement of the piston bore portion of the elastomeric diaphragm causes liquid to be drawn into the reservoir and causes air to be forced into the reservoir to mix with the liquid.
Embodiments of diaphragm foam pumps may include a housing for connecting the diaphragm foam pump to a liquid container; a piston post secured to the housing; a shell configured to at least partially fit within a neck of the liquid container and held in place by the housing. The shell may include a cylinder and a liquid inlet. In addition, a elastomeric diaphragm located at least partially between the shell and the housing. The elastomeric diaphragm includes a bellows and a piston bore. The piston bore has an opening in one end and is sized to fit over the piston post to form an air chamber and the piston bore is configured to fit at least partially within the cylinder of the shell. Movement of the piston bore over the piston post compresses the air chamber and accordingly compresses air located therein. The compressed air travels between the outside of the piston bore and the cylinder into the bellows where it mixes with the liquid and is expelled out of the pump as a foam.
These and other features and advantages of the present invention will become better understood with regard to the following description and accompanying drawings where:
An exemplary embodiment of a diaphragm foam pump 108 is illustrated in
Diaphragm 240 is molded from an elastomeric material, such as, for example, a thermoplastic elastomer (“TPE”), thermoplastic rubber (“TPR”), thermoplastic vulcanizate (“TPV”). Other suitable material may include rubber, EPDM, Nitrile, Silicon, etc. Diaphragm 240 includes piston bore 242, sealing plate 243, aperture 245 through sealing plate 243 leading to outlet cylinder 350, a one-way outlet check valve 246 and a compressible reservoir 244, such as a bellows. Preferably, diaphragm 240 is constructed of a unitary piece. Optionally, certain portions, such as outlet valve 246, are constructed separately and attached to diaphragm 240. In one embodiment, one-way outlet valve 246 is a duck-bill valve that is integrally formed with diaphragm 240, but may be any type of one-way outlet valve and may be secured to diaphragm 240 rather than integrally formed therewith. Sealing plate 243 has an opening located in the center that has a sloped wall 350. Sloped wall 350 forms a passageway with projection member 302 of shell 210 when the pump 108 is assembled. Sloped wall 350 leads to a bellows 244 which extends below the top surface of sealing plate 243. Bellows 244 partially surrounds piston bore 242 which extends up above sealing plate 243. Bellows 244 and piston bore 242 are joined at their respective bottom portions.
Bellows 244 is expandable and contractible and has an engagement member 250 located near the bottom of the bellows 244. In one embodiment, bellows 244 may be replaced by a dome pump, wherein the dome is expandable and contractible. Engagement member 250 allows an actuator (not shown) to move the piston bore 242 up and down and compress and expand bellows 244. Piston bore 242 has a sealing member 248 and is sized to fit within cylinder 212. Sealing member 248 is molded as an integral part of piston bore 242. Optionally, sealing member 248 may be formed as a separate part, such as for example, and o-ring secured to piston bore 242 by for example, a recess (not shown). Sealing member 242 forms an airtight and liquid tight seal between piston bore 242 and the inside wall of cylinder 212 when diaphragm foam pump 108 is assembled. In addition, piston bore 244 has a horizontal slit-valve 344 formed in its side wall. Horizontal slit-valve 344 may be formed by, for example, stretching the elastomeric material, slitting the material and letting the material contract. Such a process creates a slit in the material with edges that mate under normal conditions and pressure is required to allow air to pass there-thorough. Horizontal slit-valve 344 opens only under pressure to allow air to flow out of air chamber 354 in piston bore 242 to an area in the piston bore 242 and cylinder 212. In one embodiment, horizontal slit valve 344 comprises one or more small apertures, such as small pin holes. Along the bottom interior of piston bore 242 are longitudinal recesses 348 and corresponding ribs 349. Piston bore 242 is sized to snugly fit over piston post 266.
Piston post 266 is a portion of hosing 260 and piston bore 242 rides up and down on piston post 266. Housing 260 also includes a cap 360 having threads 362 for securing diaphragm foam pump 108 to container 106. Housing 260 has a base 363 with a first aperture 364 leading into cylinder 366. Outlet cylinder 352 and one-way outlet valve 246 of diaphragm 240 fit within and extending through cylinder 366. Base 363 includes a second aperture 368. Bellows 244 and air piston bore 242 of diaphragm 240 fit through aperture 368 when the pump is assembled. Housing 260 also includes one or more support arms 262 and 264 that are connected to base 268. Base 268 supports piston post 266. Support arms 262 and 264 should be rigid enough to ensure piston post 266 has little to no movement with respect to housing 260 during operation.
As actuating member 240 is moved to its upper position shown in
Diaphragm 640 is substantially the same as diaphragm 240; however, outlet cylinder 640 has a different configuration than outlet cylinder 352. Outlet cylinder 640 includes a base 646 with an aperture therethrough. Outlet valve 642, which may be for example a slit valve, rests on base 646. Outlet valve 642 may be sized to fit snugly within outlet cylinder 640. In one embodiment, a retaining ring (not shown) may be pressed into outlet cylinder 604 over the top of outlet valve 642 to hold it in place. Such a retaining ring may be slightly larger in diameter than the interior diameter of elastomeric outlet cylinder 604 and thus will be held in place by the elasticity of the walls of outlet cylinder 604. Slit valve 642 has a dome shape with a slit 644 in the center. Under pressure the dome shape inverts and the foamy mixture passes through slit 644. Upon cessation of pressure, the dome reverts back to its original shape. In one embodiment, slit valve 642 sucks back residual foamy mixture as it reverts back to its original shape.
In this embodiment, housing 660 has a modified cylinder 662. Cylinder 662 has an outlet nozzle 666 formed by tapered walls 664 of cylinder 662. In one embodiment, a foam generator 668 is placed in cylinder 662 prior to assembly of the diaphragm foam pump 600. Accordingly, the foamy mixture may be further enhanced by being forced through the foam generator 668 as it is expelled from the diaphragm foam pump.
While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, molding both the inlet and outlet valve into the elastomeric diaphragm makes it possible to fabricate the entire pump with three parts. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicants' general inventive concept.
Claims
1. A refill unit for a foam dispenser comprising:
- a liquid container and
- a diaphragm foam pump connected to the liquid container;
- the diaphragm foam pump including; an elastomeric diaphragm having an air piston bore portion and a compressible reservoir portion formed as a unitary piece; the air piston bore portion forming at least a portion of an air chamber; a liquid inlet into the compressible reservoir; a piston forming at least a portion of the air chamber, wherein the piston bore moves relative to the piston to compress air;
- wherein movement of the air piston bore portion relative to the piston in a first direction causes air in the air chamber to be compressed and draws liquid into the reservoir and wherein further movement of the air piston bore causes compressed air to be released from the air chamber and to flow into the reservoir.
2. The refill unit of claim 1 wherein the piston is stationary and the compressible reservoir is a bellows.
3. The refill unit of claim 2 wherein the air piston bore has a slit valve located in a wall.
4. The refill unit of claim 2 wherein the air piston bore is located at least partially within the reservoir.
5. The refill unit of claim 2 wherein the piston is secured to a cap which connects to the liquid container.
6. The refill unit of claim 2 further comprising an outlet passage from the reservoir that has a first cross-sectional area that is different than a second cross-sectional area.
7. The refill unit of claim 2 further comprising one or more recesses in the piston bore for allowing air to enter the air chamber.
8. A diaphragm foam pump comprising:
- an elastomeric diaphragm having an air piston bore portion and a bellows portion, wherein the air piston bore portion is located at least partially within the bellows portion;
- a reservoir at least partially formed by the bellows and the outside of the piston bore portion;
- a liquid inlet into the reservoir;
- a piston post, wherein the piston bore moves relative to the piston post to compress air;
- an air inlet into the reservoir; wherein movement of a portion of the elastomeric diaphragm causes liquid to be drawn into the reservoir and causes air to be forced into the reservoir to mix with the liquid.
9. The diaphragm foam pump of claim 8 comprising an air outlet in a wall of the air piston bore wherein the air is sized to restrict air flow therethrough.
10. The diaphragm foam pump of claim 9 wherein the air outlet is a slit valve.
11. The diaphragm foam pump of claim 8 further comprising an outlet passage that has a first portion with a first cross-sectional area and a second portion with a second cross-sectional area that is greater than the first.
12. The diaphragm foam pump of claim 8 wherein the piston post is secured to a cap that is securable to a liquid container.
13. The diaphragm foam pump of claim 8 further comprising a container filled with a foamable liquid.
14. The diaphragm foam pump of claim 8 wherein the liquid inlet passage is formed between a portion of a shell and the diaphragm.
15. A diaphragm foam pump comprising:
- a housing for connecting the diaphragm foam pump to a liquid container;
- a piston post secured to the housing;
- a shell configured to at least partially fit within a neck of the liquid container and held in place by the housing;
- the shell having a cylinder and a liquid inlet located therein;
- an elastomeric diaphragm located at least partially between the shell and the housing;
- the elastomeric diaphragm having a bellows and a piston bore;
- the piston bore having an opening in one end sized to fit over the piston post to form an air chamber;
- the piston bore configured to fit at least partially within the cylinder of the shell; wherein movement of the piston bore over the piston post compresses the air chamber and compresses air located therein; and compressed air travels between the outside of the piston bore and the cylinder into the bellows.
16. The diaphragm foam pump of claim 15 further comprising an outlet duck-bill valve.
17. The diaphragm foam pump of claim 15 wherein the piston bore has a slit valve through one of its walls for the compressed air to pass therethrough.
18. The diaphragm foam pump of claim 15 wherein the outlet valve is integrally formed with the elastomeric diaphragm.
19. The diaphragm foam pump of claim 15 wherein the piston bore comprises one or more elongated recesses for allowing air to enter the air chamber.
20. The diaphragm foam pump of claim 15 wherein the elastomeric diaphragm further comprises an actuator member for engaging with a dispenser actuator.
Type: Application
Filed: Oct 13, 2011
Publication Date: Apr 18, 2013
Applicant: GOJO INDUSTRIES, INC. (Akron, OH)
Inventor: Keith Allen Pelfrey (Wadsworth, OH)
Application Number: 13/272,443
International Classification: F04B 45/02 (20060101); F04B 43/02 (20060101);