Abstract:
A foam dispenser includes a housing and a refill unit. The refill unit carries a tube pump for pumping a foamable liquid, and the housing carries an air pump for pumping air. The tube pump and air pump fluidly communicate premixed chamber in a mixing unit to create a foam product when the dispenser is actuated to actuate both the 2 pump and the air pump.

Description:
TECHNICAL FIELD 
       [0001]    The invention herein resides in the art of foam dispensers wherein a foamable liquid and air are combined to dispense a foam product. More particularly, the invention relates to a dispenser wherein a liquid tube pump is provided as part of a disposable refill unit containing the liquid, and an air pump is provided as part of the dispenser housing. 
       BACKGROUND OF THE INVENTION 
       [0002]    For many years, it has been known to dispense liquids, such as soaps, sanitizers, cleansers, disinfectants, and the like from a dispenser housing maintaining a refill unit that holds the liquid and provides the pump mechanisms for dispensing the liquid. The pump mechanism employed with such dispensers has typically been a liquid pump, simply emitting a predetermined quantity of the liquid upon movement of an actuator. Recently, for purposes of effectiveness and economy, it has become desirable to dispense the liquids in the form of foam, generated by the interjection of air into the liquid. Accordingly, the standard liquid pump has given way to a foam generating pump, which necessarily requires means for combining the air and liquid in such a manner as to generate the desired foam. However, foam generating pumps are more expensive than liquid dispensing pumps, necessarily increasing the cost of a refill unit that includes the pump mechanism. 
         [0003]    Typically, foam pumps include an air pump portion and a fluid pump portion—the two requiring communication to ultimately create the foam. It has been found that the air pump portion required for pumping the air does not wear out and degrade as quickly as the liquid pump portion required for pumping the liquid. Additionally, the air pump portion mainly comes into contact with air and thus stays more sanitary, making its periodic replacement less necessary than in the case of the liquid pump portion and the foam generating portion of a foam dispenser. Accordingly, it has been determined that it is not as necessary to replace the air pump as it is to replace the liquid pump and foam generating portion of the dispenser when replacement of the refill unit is necessary. Accordingly, there is a need in the art for foam dispensing systems that employ a disposable liquid pump and a more permanent air pump. 
       SUMMARY OF THE INVENTION 
       [0004]    In light of the foregoing, this invention provides a dispenser including a housing and a refill unit. The housing includes an air bellows having and expanded volume and a compressed volume and retaining its expanded volume when the dispenser is not being actuated. The housing further includes a container support, a pump anvil, and a push bar. The push bar provides a pump plate portion and an air bellows actuator, and is capable of reciprocal movement toward and away from the pump anvil. The refill unit includes a container holding a foamable liquid, and a tube pump fluidly communicating with the foamable liquid in the container. The tube pump includes a collapsible tube, and the flow of foamable liquid into and out of the collapsible tube is regulated by a tube pump inlet valve and a tube pump outlet valve. The container fluidly communicates with the collapsible tube through the tube pump inlet valve. The refill unit further includes a mixing unit, and the collapsible tube communicates with the mixing unit through the tube pump outlet valve. The mixing unit includes an air bellows adaptor that is secured to an air outlet of the air bellows to fluidly communicate with the air bellows through an air bellows valve. The dispenser is actuated by moving the push bar toward the pump anvil, with such movement squeezing the collapsible tube between the push plate portion and the pump anvil to force foamable liquid therein through the tube pump outlet valve and into the mixing unit, such movement also causing the air bellows actuator to move the air bellows to its compressed volume to force air therein through the air bellows outlet valve and into the mixing unit. 
         [0005]    Although the various elements of the dispenser as summarized above include particular elements as part of either a housing or a refill unit, this invention is not limited thereto or thereby, and it should be appreciated that the various dispenser elements may be provided in other ways, provided the various elements interact and function as taught herein. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is cross sectional view of an embodiment of a dispenser of this invention; and 
           [0007]      FIG. 2  is a cross sectional view of a mixing cartridge. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0008]    With reference to  FIG. 1 , the dispenser of this invention is shown and designated by the numeral  10 . The dispenser  10  includes a housing  12  adapted to receive and hold a refill unit  14 . Although the housing may take other forms, in this embodiment, the housing  12  is of the common type that includes a cover  16  secured to a backplate  18 . A container support  20  is provided as part of backplate  18 , here, in the form of a ledge  22 . A pump anvil  24  is provided below the ledge  22 , and an air bellows  26  extends outwardly from backplate  18  below the pump anvil  24 . The cover  16  includes a push bar  27 , which, when the cover  16  is closed on backplate  18 , aligns over both the pump anvil  24  and the air bellows  26 . More particularly, the push bar  27  provides a pump plate portion  28 , which aligns with the pump anvil  24 , and an air bellows actuator  30  that extends toward and connects to air bellows  26 . 
         [0009]    The refill unit  14  provides a container  32  holding a foamable liquid S. It is a collapsible container as known in the art. The container  32  is placed in the housing  12  on the container support  20 . A dispensing tube  34  extends down from the container  16 , and feeds foamable liquid S from container  16  to a tube pump  36 . The tube pump  36  includes a collapsible tube  38  positioned between the pump anvil  24  and the push plate portion  28  of the push bar  27  and is preferably secured to push bar  27  to move therewith. A tube pump inlet valve  40  regulates flow of the foamable liquid S into the collapsible tube  38 , and a tube pump outlet valve  42  regulates the flow of foamable liquid S out of the collapsible tube  38  and into a mixing unit  44 . These valves are shown as common spring biased ball valves, but other valves may be used to join with an air source. The mixing unit  44  includes an air bellows adaptor  46  extending to mate with the air bellows  26 . 
         [0010]    The air bellows  26  includes a bellows body  48  that is sealed to backplate  18  at base  50 , and is open at outlet  52 . The bellows body  48  is corrugated, as at ridges  54  and valleys  56 , and is made of a material that provides the bellows body  48  with the ability to reversibly collapse and extend between a compressed volume and an expanded volume. The air bellows adaptor  46  of the mixing unit  44  is sealed around the outlet  52  of the air bellows  26 , and the air bellows  26  fluidly communicates with the mixing unit  44  through an air bellows valve  59  (again as a ball valve, though not limited thereto) provided as part of the mixing unit  44 . 
         [0011]    The air bellows actuator  30  extends toward air bellows  26  and bypasses the tube pump  36  at an aperture  31 . A mount ridge  60  of bellows body  48  is fed through an aperture  62  in the air bellows actuator  30  so that the air bellows actuator  30  will impact the first ridge  54  when urged in the direction of arrow A. 
         [0012]    When the refill unit  14  is properly mounted in the housing  12  and the cover  16 , the dispenser  10  is actuated to dispense a foam product by moving the push bar  27  in the direction of arrow A. By moving the push bar  27  in the direction of arrow A, the collapsible tube  38  is squeezed between the push plate portion  28  of the push bar  27  and the pump anvil  24 . This forces foamable liquid in the collapsible tube  38  through the tube pump outlet valve  42  and into the mixing unit  44 . This movement of the push bar  27  also causes the air bellows actuator  30  to press against the first ridge  54  of the bellows body  48 , thus compressing the air bellows  26  to its compressed volume to force air therein through the outlet  52  of air bellows  46  and through the air bellows valve  59  into the premix passage  66  of the mixing unit  44 . Thus, foamable liquid S and air mix at the premix chamber  66  to form a coarse mixture. During actuation, this coarse mixture is forced through a mesh screen  68  to homogenize mixture and create a high quality foam product that is dispensed at the outlet  70 . As can be seen in  FIG. 2  the mesh screen  68  can be replaced with a mixing cartridge  72 , which includes a hollow tube  74  bounded on both ends by mesh screens  76  and  78 . 
         [0013]    In light of the foregoing, it should be apparent that the present invention improves the art by providing a foam dispenser having a liquid tube pump refill unit that is separate and distinct from an air pump unit, namely an air bellows. While a particular embodiment of this invention has been the focus for purposes of disclosing the invention, it should be appreciated that this invention can be modified in various ways without departing from the general concepts taught herein. Thus, this invention is not to be limited to or by any particular embodiment, rather, the claims will serve to define the invention.