Mini pump with compressible air inlet chamber for providing residual suck-back

Exemplary dispensers, pumps and refill units are disclosed herein. An exemplary refill unit includes a container and a foam pump. The foam pump includes a liquid pump chamber, a compressible air inlet chamber and a compressed air inlet. The volume of the compressible air inlet chamber is less than the volume of air used to make a dose of foam. A one-way air inlet valve is located proximate the compressed air inlet. A piston is included that is movable within the liquid pump chamber and has a liquid seal member and an air seal member. The liquid pump chamber includes a liquid outlet into a center portion of the piston. One or more openings extend through the piston wall and provide a passage from the compressible air chamber to the center portion of the piston. The pump further includes mix media and an outlet.

TECHNICAL FIELD

The present invention relates generally to pumps, refill units for dispensers and dispenser systems, and more particularly to inverted liquid and foam pumps having a compressible air inlet chamber for providing residual suck back, as well as a disposable refill/replacement unit including such pumps.

BACKGROUND OF THE INVENTION

Liquid dispenser systems, such as liquid soap and sanitizer dispensers, provide a user with a predetermined amount of liquid upon actuation of the dispenser. In addition, it is sometimes desirable to dispense the liquid in the form of foam by, for example, injecting air into the liquid to create a foamy mixture of liquid and air bubbles. As a general matter, it is usually preferable to reduce the space taken up by the pumping and foaming apparatus within the overall dispenser system. This maximizes the available space for storing the liquid, and has other benefits. After dispensing a dose of foam, some of the residual foam remains in the outlet nozzle of the pump. In many inverted foam dispensers the residual foam turns into a liquid and drips out of the outlet nozzle creating a mess under the dispenser.

SUMMARY

Exemplary dispensers, pumps and refill units are disclosed herein. An exemplary refill unit includes a container. The container includes a neck. A foam pump is secured to the neck. The foam pump includes a liquid pump chamber, a compressible air inlet chamber and a compressed air inlet that receives compressed air having an air pressure of greater than ambient air pressure. The volume of the compressible air inlet chamber is less than the volume of air used to make a dose of foam. A one-way air inlet valve is located proximate the compressed air inlet. A piston is included that is movable within the liquid pump chamber. The piston has a liquid seal member for providing a movable seal against a wall of the liquid pump chamber and an air seal member for providing a movable seal against a wall of the compressible air inlet chamber. The liquid pump chamber includes a liquid outlet into a center portion of the piston. One or more openings extend through the piston wall and provide a passage from the compressible air inlet chamber to the center portion of the piston. One or more foaming elements are located within the piston and an outlet is located at the distal end of the piston.

Another exemplary refill unit includes a container. The container has a neck located at the bottom of the container. A foam pump is secured to the neck. The foam pump has a liquid pump chamber, a compressed air inlet, a compressible air inlet chamber located downstream of the compressed air inlet, a mixing chamber and one or more mixing elements located downstream of the mixing chamber. When the volume of the liquid pump chamber is reduced, liquid flows into the mixing chamber and compressed air flows in through the compressed air inlet, through the compressible air inlet chamber and into the mixing chamber to mix with liquid flowing out of the liquid pump chamber. The mixture of liquid and compressed air flow through the one or more mixing elements and is dispensed as a foam. When the volume of the liquid pump chamber is increased, the volume of the compressible air inlet chamber increases and draws residual foam and/or liquid up toward the compressible air inlet chamber.

Another exemplary refill unit includes a container having a neck and a foam pump. The foam pump includes a piston, a liquid pump chamber, a compressible air inlet chamber and a compressed air inlet that receives compressed air having an air pressure of greater than ambient air pressure. A one-way air inlet valve proximate the air inlet for allowing air to flow into the compressible air inlet chamber and preventing fluid from flowing out of the compressed air inlet is also included. A piston is movable within the liquid pump chamber and the compressible air inlet chamber. The piston has a liquid seal member for sealing against a wall of the liquid pump chamber and an air seal member for sealing against a wall of the compressible air inlet chamber. The liquid pump chamber has a liquid outlet into a center of the piston. One or more openings extend through the piston wall providing a passage from the compressible air chamber to a mixing chamber in the center of the piston. One or more foaming elements are located at least partially within the piston; and an outlet located at the distal end of the piston.

DETAILED DESCRIPTION

FIG. 1illustrates an exemplary embodiment of a foam dispensing system100. Foam dispensing system100includes a disposable refill unit110for use in a foam dispenser105. The disposable refill unit110includes a container112connected to a pump120. Pump120includes a compressed air inlet156. The disposable refill unit110may be placed within a housing of the dispenser105and the compressed air inlet156releasably placed in fluid communication with air compressor150.

The foam dispenser system100may be a wall-mounted system, a counter-mounted system, an un-mounted portable system movable from place to place or any other kind of foam dispenser system. Foam dispenser105includes an air compressor150permanently mounted to foam dispenser105. Air compressor150includes an air conduit152with a connector154for releasably connecting to the compressed air inlet156of pump120. Optionally, connector154may be secured to the compressed air inlet156pump120. In one embodiment, connector154is a two-part connector, and one part is connected to pump120and the other to air conduit152. Accordingly, refill unit110and pump120may be removed from dispenser housing105and discarded without removal of the air compressor150. Connector154may be a quick release connector, a releasable snap-fit connector, a releasable compression-fit connector or a sealing member such as, for example, a foam member that compresses to form a seal between air conduit152and compressed air inlet156of pump120.

The container112forms a liquid reservoir114. The liquid reservoir114contains a supply of a foamable liquid within the disposable refill unit110and the dispenser housing105which holds the refill unit110. In various embodiments, the contained liquid could be for example a soap, a sanitizer, a cleanser, a disinfectant or some other foamable liquid. In the exemplary disposable refill unit110, the liquid reservoir114is formed by a collapsible container112, such as a flexible bag-like container. In other embodiments, the liquid reservoir114may be formed by a rigid housing member, or have any other suitable configuration for containing the foamable liquid without leaking. If the container112is not collapsible, a vent (not shown) may be included to alleviate vacuum pressure from building up in container112. The container112may advantageously be refillable, replaceable or both refillable and replaceable. In other embodiments, the container112may be neither refillable nor replaceable.

In the event the liquid stored in the reservoir114of the installed disposable refill unit110runs out, or the installed refill unit110otherwise has a failure, the installed refill unit110may be removed from the foam dispenser system100. The empty or failed disposable refill unit110may then be replaced with a new disposable refill unit110including a liquid-filled reservoir114. The air pump150remains located within the foam dispenser system100while the disposable refill unit110is replaced. In one embodiment, the air pump150is also removable from the housing of the dispenser system, separately from the disposable refill unit110, so that the air pump150may be replaced without replacing the dispenser105, or alternatively to facilitate removal and connection to the refill unit110. Sanitary sealing isolates the air pump150from the portions of the foam pump120that contact liquid so that the air pump mechanism does not contact liquid during operation of the foam pump120. Sanitary sealing may be achieved with a one-way valve as described in more detail below.

The housing of the dispensing system100further contains an actuator160to activate the foam pump120. Actuator160is connected to foam pump120by linkage162. Actuator160and linkage162are generically shown as it will be appreciated by one of ordinary skill in the art, there are many different kinds of pump actuators, linkages and gearing which may be employed in the foam dispenser system100. The pump actuator of the foam dispenser system may have any type of actuator, such as, for example, a manual lever, a manual pull bar, a manual push bar, a manual rotatable crank, an electrically activated actuator or other means for actuating the foam pump120within the foam dispenser system100. Electronic pump actuators may additionally include a motion detector164to provide for a hands-free dispenser system with touchless operation. Various intermediate linkages162connect actuator160to the foam pump120within the dispenser housing105, the linkages may include gears, racks, pinions and the like. The exemplary foam pump120is a “push-activated” pump. That is, the pump120dispenses foam by pushing a nozzle upward. The external actuator may be operated in any manner, so long as the intermediate linkages transform that motion to an upward force on the nozzle170. In some embodiments, foam pump120includes a spring to return nozzle170to its downward position. In some embodiments, actuator160moves the nozzle170to its downward most position. Nozzle170includes annular protrusions171,172for engaging with linkage162to move nozzle170. In addition, nozzle170has an outlet175for dispensing foam, and dispenser housing105includes an opening106that allows foam to be dispensed to a user.

Air pump150includes an air inlet155having a one-way air inlet valve156. One-way air inlet valve156allows air to enter air pump150to recharge the air pump150. In some embodiments, the air inlet155is located inside of housing105so that air from inside of the dispenser housing105is used to feed the air pump150. Using air from inside the housing105may help prevent moisture from entering air pump150through air inlet155and air inlet valve156. In some embodiments, a vapor barrier157is provided. Vapor barrier157allows air to pass through and the air inlet and enter the air pump150, but prevents moisture from entering air pump150. A suitable vapor barrier is a woven one-way vapor barrier, such as, for example, Gortex®, that is arranged so that vapor does not enter air pump150. Preventing moisture from entering air pump150may prevent mold and bacteria from growing inside the air pump and contaminating the dispensed foam. The term “air pump” and “air compressor” may be used interchangeably herein and have the same meaning, namely a device for providing compressed air at a pressure that is higher than the ambient air pressure.

In one embodiment, air pump150includes an anti-microbial substance molded into the air pump housing. One suitable anti-microbial substance contains silver ions and or copper ions. A silver refractory, such as, for example, a glass, oxide, silver phosphate may be used. One suitable commercially available product is Ultra-Fresh, SA-18, available from Thomson Research Associates, Inc. The anti-microbial substance prevents mold or bacteria from growing inside of the air pump150.

FIGS. 2 and 3are partial cross-sections of an exemplary embodiment of a refill unit200that includes pump210and container202for use in the exemplary foam dispensing system100. Container202includes a neck204. Pump210includes a housing211. Housing211includes a collar212. Collar212secures pump210to the neck204of container202. Collar212may be secured to neck204by any means, such as, for example, a threaded connection as shown, a snap-fit connection, an adhesive connection, a welded connection or the like. Pump housing211includes a cylindrical wall213that extends at least partially up into neck204. An upper wall214is located at the upper end of cylindrical wall213. One or more liquid apertures215are located in upper wall214and a one-way liquid inlet valve216is located proximate the one or more liquid inlet apertures215. One-way liquid inlet valve216allows liquid to flow into a pump chamber220that is formed in part by cylindrical wall213and upper wall214. One-way liquid inlet valve216may be any type of valve that allows liquid to flow into pump chamber220and prevents liquid from flowing out of pump chamber220back into container202.

Pump housing211includes a lower cylindrical wall219. A compressed air inlet opening217is located through cylindrical wall219. An air inlet conduit218surrounds the air inlet opening217. A one-way air inlet valve280is located in air inlet conduit218. One-way air inlet valve280prevents fluid from flowing from the pump210back toward a compressed air source (not shown), such as the air pump150shown inFIG. 1. Pump housing211also includes a piston stop221that retains a piston250in pump housing211.

Piston250includes an upper portion252that forms part of the liquid pump chamber and includes a cylindrical wiper seal254that engages with cylindrical wall213. Wiper seal254may be made of the same material as piston250or of a different material. One or more liquid outlet openings256are located in the floor of the upper portion252. A one-way liquid outlet valve258is located proximate the one or more liquid outlet openings256. The one-way outlet valve256and liquid outlet openings256allow liquid to flow out of the liquid pump chamber220and into mixing chamber275located in the center of piston250.

Piston250also includes a lower portion260. Lower portion260has a cylindrical wall that includes a plurality of openings262providing a path from a compressible air inlet chamber222located on the exterior of lower portion260into the mixing chamber275. Piston250also includes mix media or foaming elements, such as, for example, screens274located downstream of the mixing chamber to create turbulence in the mixing of air and foamable liquid. Piston250includes a nozzle portion270having annular projections271,272for engaging with an actuator of a dispenser.

An air wiper seal264that engages with cylindrical wall219to form the compressible air inlet chamber222is also provided on piston250. In some embodiments, the air wiper seal264is made of the same material as piston250and in some embodiments is made of a different material and secured to piston250.

A biasing member290, such as, for example, a spring, biases the piston toward its downward most position shown inFIG. 2, with piston stop219preventing the piston250from further downward movement. In some embodiments, biasing member290is not used and the actuator (not shown) moves the nozzle270in both the upward dispensing direction and downward priming direction.

FIG. 2illustrates the pump210in a primed position ready to dispense a dose of foam. During operation, nozzle270, and accordingly, piston250is pushed upward to dispense foam. As piston250moves upward, liquid wiper seal254engages cylindrical wall213and the volume of liquid pump chamber220is compressed pushing liquid into mixing chamber275. The lower portion260of piston250also moves upward. As it does so, air wiper seal264moves along cylindrical wall219and the volume of compressible air chamber222is compressed pushing a small amount of air and any residual liquid into the mixing chamber. The volume of the compressible air inlet chamber222is less than the volume of air that is required to produce one dispense of foam. Simultaneous to the movement of piston250upward, compressed air from an air pump (not shown) is forced past one-way air inlet valve280through air conduit218through compressible air inlet chamber222, through openings262and into the mixing chamber275. The liquid and air mix in the mixing chamber275and the mixture is forced through mix media274and out of nozzle270in the form of a foam.

Once a dispense cycle has been completed, shown inFIG. 3, piston250is urged back its rest or primed position shown inFIG. 2. As the piston250moves back to its rest position liquid is drawn into liquid chamber220. In addition, residual foam and liquid in the mixing chamber275, mix media274and nozzle270are drawn up toward, and in some embodiments into, compressible air inlet chamber222as its volume expands. Accordingly, the compressible air inlet chamber222sucks back residual fluid and prevents dripping of the foam dispenser after a dispense cycle is completed.

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. Moreover, elements described with one embodiment may be readily adapted for use with other embodiments. 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.