Abstract:
Exemplary two chamber foam pumps, refill units and dispensers utilizing the same are disclosed herein. An exemplary refill unit includes an inverted container having a neck located at the bottom of the container and a foam pump secured neck. The foam pump includes a first air pump chamber, a liquid pump chamber and a second air pump chamber. In addition, the pump includes a piston. The piston has a hollow central portion. A first air inlet aperture is located through a wall of the piston between the first air pump chamber and the hollow central portion. A liquid inlet aperture is located below the first air inlet aperture and between the liquid pump chamber and the hollow central portion. A second air inlet aperture is located through the wall the piston located below the liquid inlet aperture and between the second air pump chamber and the hollow central portion.

Description:
RELATED APPLICATIONS 
     This application claims priority to and the benefits of U.S. Provisional Patent Application Ser. No. 62/003,951 filed on May 28, 2014 and entitled “DUAL AIR CHAMBER FOAM PUMPS, REFILL UNITS AND DISPENSERS,” which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to foam pumps, refill units and dispenser systems and more particularly dual air chamber foam pumps, refill units and dispensers utilizing dual air chamber foam pumps. 
     BACKGROUND OF THE INVENTION 
     Liquid dispenser systems, such as liquid soap and sanitizer dispensers, provide a user with an amount of foam upon actuation of the dispenser. In order to create a foam output having a desirable characteristic, the air to liquid ratio is generally about 10 to 1. To accomplish this, most prior art foam pumps have an air pump chamber that has an outside diameter that is larger than the interior diameter of the neck of the container. Consequently, the air pump chamber is typically located outside of the neck of the container. Locating the air pump chamber outside of the container increases the overall size of the refill and increases the shipping costs. 
     SUMMARY 
     Exemplary two chamber foam pumps, refill units and dispensers utilizing the same are disclosed herein. An exemplary refill unit includes an inverted container having a neck located at the bottom of the container and a foam pump secured neck. The foam pump includes a first air pump chamber, a liquid pump chamber and a second air pump chamber. In addition, the pump includes a piston. The piston has a hollow central portion. A first air inlet aperture is located through a wall of the piston between the first air pump chamber and the hollow central portion. A liquid inlet aperture is located below the first air inlet aperture and between the liquid pump chamber and the hollow central portion. A second air inlet aperture is located through the wall the piston located below the liquid inlet aperture and between the second air pump chamber and the hollow central portion. The refill unit also includes an outlet. 
     Another exemplary refill unit includes an inverted container having a neck located at the bottom of the container, foamable liquid contained in the inverted container and a pump secured neck. The pump has a first cylindrical chamber, a second cylindrical chamber; and a third cylindrical chamber. The pump includes a first air pump wiper seal is movable in a reciprocating fashion within the first cylindrical chamber. In addition, a second air pump wiper seal is included that is movable in a reciprocating fashion within the third cylindrical chamber. A pair of opposing liquid pump wiper seals is movable in a reciprocating fashion within the second cylindrical chamber. A foam outlet nozzle is also included. A passage is located between the first cylindrical chamber, the second cylindrical chamber, the third cylindrical chamber and the foam outlet nozzle. An opening in the first cylindrical chamber allows liquid to contact a top portion of the first air pump wiper seal and an opening in the third cylindrical chamber allows liquid to contact a top portion of second air pump wiper seal. 
     Another exemplary refill unit includes an inverted container having a neck located at the bottom of the container. A foamable liquid is contained in the inverted container and a foam pump is secured neck. The foam pump includes a first cylindrical member forming a portion of an air pump chamber, a second cylindrical member forming a portion of a liquid pump chamber and a third cylindrical member forming a portion of a second air pump chamber. The foam pump includes a piston having a second air pump sealing member movable within the second air pump chamber to pump air and also includes an opening between the interior of the container and the interior of the upper portion of third cylindrical chamber. The opening allows liquid to flow into the upper portion of the third cylindrical chamber and contact the upper portion of the second air pump sealing member. 
     In this way, a simple and economical dual air chamber foam pumps, refill units and dispensers for same are provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will become better understood with regard to the following description and accompanying drawings in which: 
         FIG. 1  is a cross-section of an exemplary liquid dispenser having a refill unit with a vertical pump; and 
         FIGS. 2 and 3  are partial cross-sections of an exemplary refill unit having dual air chamber foam pump. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exemplary embodiment of a dispenser  100  with a vertically operated pump  120 . (The cross-section of  FIG. 1  is taken through the housing  102  to show the foam pump  120  and container  116 ). Foam pump  120  is a dual air chamber foam pull pump. Dispenser  100  includes a disposable refill unit  110 . The disposable refill unit  110  includes a container  116  having a neck  117  connected to pump  120 . The dispenser  100  may be a wall-mounted system, a counter-mounted system, an un-mounted portable system movable from place to place or any other kind of liquid dispenser system. 
     The container  116  forms a liquid reservoir that contains a supply of foamable liquid within the disposable refill unit  110 . In various embodiments, the contained liquid could be, for example, a soap, a sanitizer, a cleanser, a disinfectant, a lotion or the like. In the exemplary disposable refill unit  110 , the container  116  is a collapsing container and can be made of thin plastic or like material. The container  116  may advantageously be refillable, replaceable or both refillable and replaceable. In some embodiments, the container  116  is non-collapsing and a vent (not shown) is provided to vent the container  116  with air to prevent a vacuum in the container  116  that would prevent the foam pump  120  from priming. 
     In the event the liquid stored in the container  116  of the installed disposable refill unit  110  runs out or the installed refill unit  110  otherwise has a failure, the installed refill unit  110  may be removed from the foam dispenser  100 . The empty or failed disposable refill unit  110  may then be replaced with a new disposable refill unit  110 . 
     The housing  102  of the dispenser  100  contains one or more actuating members  104  to activate the pump  120 . As used herein, actuator or actuating members or mechanisms include one or more parts that cause the dispenser  100  to move liquid, air and/or foam. Actuator  104  is generically illustrated because there are many different kinds of pump actuators which may be employed in the foam dispenser  100 . The actuator  104  of the foam dispenser  100  may be 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 pump  120 . Electronic actuators may additionally include a sensor  132  for detecting the presence of an object and to provide for a hands-free dispenser system with touchless operation. Various intermediate linkages, such as for example linkage  105 , connects the actuator member  104  to the pump  120  within the dispenser housing  102 . An aperture  115  is located in bottom plate  103  of housing  102  and allows fluid dispensed from the nozzle  125  of pump  120  to be dispensed to a user. In one exemplary embodiment, during operation, actuator  104  and linkage  105  move nozzle  125  of pump  120  to its upward-most position (as shown in  FIG. 1 ) to prime or charge the foam pump  120 . The actuator  104  and linkage  105  pulls nozzle  125  downward to dispense a foam product. 
       FIGS. 2 and 3  are partial cross-sections of an exemplary embodiment of refill unit  110 .  FIG. 2  illustrates pump  110  in its primed state and  FIG. 3  illustrates pump  110  in its dispensed state. Pump  110  includes a first cylindrical housing  202  and second smaller cylindrical housing  204 . First cylindrical housing  202  forms a part of a first air pump chamber  203 . Second cylindrical housing  204  extends partway up into first cylindrical housing  202 . The top of first cylindrical housing  202  is open to the container  116 . Seal plate  210  snaps on to a lower flared out portion  206  of second cylindrical housing member  204 . 
     Seal plate  210  includes one or more openings  212  therethrough for liquid to flow up into liquid chamber  205  which is formed in part by second cylindrical housing  204 . The outer portion of an annular seal  214  is compressed between the bottom of second cylindrical housing  202  and seal plate  210  to secure the annular seal  214  in place. The annular seal  214  acts of one-way liquid inlet valve that allows fluid to flow through one or more openings  212  up into liquid chamber  205 . Seal plate  210  also includes wiper seal  216  which forms a seal against a stem portion  251  of piston  250 . 
     Secured to seal plate  210  is a third cylindrical housing  220 . Third cylindrical housing  220  has a base that includes a wiper seal  223  that seals against stem portion  252  of piston  250 . Third cylindrical housing  220  also includes one or more slits  225  that provide a pathway for liquid in container  116  to flow into the upper portion of the third cylindrical housing member  206 . In some embodiments, slits  225  may be replaced by one or more apertures. Third cylindrical housing  220  also includes a closure member  224 . Closure member  224  secures pump  110  to the neck  117  of container  116 . A gasket (not shown) may be included in closure member  224  to seal between closure  224  and the top of neck  117  to provide additional leakage protection. Third cylindrical housing  220  forms a portion of second air pump chamber  221 . Third cylindrical housing  220  also forms a portion of a liquid pumping chamber  222 . 
     Piston  250  has a first air pump wiper seal  252  that reciprocates within first cylindrical housing  202 . In addition, piston  250  has a hollow central portion  262  that is sealed off at the top by plate  263 . Located below plate  263  are one or more first air inlet openings  254  that provide a passageway from first air pump chamber  203  into the hollow central portion  262  of piston  250 . 
     Piston  250  also includes a pair of opposed liquid wiper seals  256  and  258  that reciprocate up and down in second cylindrical housing member  204 . One or more liquid inlet openings  260  are located between the pair of opposed liquid wiper seals  256 ,  258  and below the first air inlet openings  254 . The one or more liquid inlet openings  260  allow foamable liquid to pass from liquid chamber  205  into the hollow central portion  262  of piston  250 . 
     In addition, piston  250  includes a second air pump wiper seal  272  that reciprocates up and down in third cylindrical housing  206 . Piston  250  has one or more second air inlet openings  274  that allow air to move between second air chamber  221  and the central portion  262  of piston  250 . Second air inlet openings  274  are angled upward. Second air inlet openings  274  are located below liquid inlet openings  260 . In some embodiments, the second air inlet openings are located proximate the second air pump wiper seal  272 . 
     Piston  252  includes mix media  276 . Mix media  276  may be for example, a pair of screens  276 . In some embodiments, mix media  276  may be a plurality of baffles, one or more porous members, or the like that impart turbulence in the flow path in hollow central portion  262  and create a thorough mixing of the air and foamable liquid to create a rich foam is dispensed out of outlet  281  of nozzle  125 . Nozzle  125  includes a first cylindrical projecting member  282  and a second cylindrical projecting member  284  that releasably engage with an actuator (not shown) to move piston  250  up and down. 
     In some embodiments a shipping seal  218  is also included. Shipping seal  218  is part of seal plate  210 , however shipping seal  218  may be a separate part affixed to seal plate  210 . Shipping seal  218  engages an annular groove  219  on wiper seal  272 . When the refill unit  110  is shipped, shipping seal  218  fits within annular groove  219  and provides a sealing mechanism to seal a potential leakage passage that might allow the refill unit  110  to leak during shipping. 
     Pump  110  is shown as primed position in  FIG. 2 . As pump  110  is moved to the position shown in  FIG. 3 , first pump chamber  203  is compressed and air from first pump chamber  203  flows through one or more openings  254  into the central portion  262  of stem  251 . Simultaneously liquid from liquid chamber  205  flows past wiper seal  258  through one or more openings  260  into the hollow central portion  262  of stem  251  where it mixes with the air and is forced downward through hollow central portion  262 . 
     In addition second air pump chamber  221  is compressed forcing air up through one or more openings  274  in the central portion  262  of stem portion  252 . Thus, air from second air pump chamber  221  also mixes with the air and liquid mixture flowing through hollow central portion  262  which adds air to the mixture and helps force the air and liquid mixture to flow through mix media  276  were is converted to rich foam. The rich foam is dispensed out of outlet  281 . 
     In addition, liquid flows from container  116  through one or more slots  225  into liquid pumping chamber  222 . Fluid also flows from container  116  into the upper portion  207  of first cylindrical housing member  202  (if the liquid is above the top of first cylindrical housing  202 ). 
     As piston  250  moves from the dispensed position shown in  FIG. 3  to the primed position shown in  FIG. 2 , air and residual foam flow up the hollow central portion  262  of stem portions  252 . The residual foam is sucked into the second air chamber  221  which prevents dripping. Liquid is pushed out of liquid pumping chamber  222 . A portion the liquid flows through one or more openings  212 , past annular seal  214  and into liquid chamber  205 . The remainder the liquid in liquid pumping chamber  222  is forced back through one or more slits  225  into container  116 . The liquid in the upper portion  207  of first cylindrical housing  202  is also pushed up and into the container  116 . 
     In some embodiments forcing liquid out of liquid pump chamber  222  helps to mix the contents of container  116 . This may be beneficial if the liquid contains ingredients that may separate out of the foamable liquid and settle to the bottom of the container, such as, for example, zinc. In some embodiments, a screen (not shown) covers slits  225  and material, such as for example, glitter, sparkles, colored balls, or the like, located within container  116  are forced upward by the returning liquid in the container which provides a positive visual display. Such visual displays may encourage children to use the soap or sanitizing dispenser. As piston  250  is moved upward, liquid fills liquid chamber  205  and air fills first air chamber  203  and second air chamber  201 . At this point pump  110  is primed and ready to dispense another dose of foam. 
     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 applicant 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. 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 applicant&#39;s general inventive concept.