CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This utility patent application is a non-provisional of and claims priority to and the benefits of U.S. Provisional Patent Application Ser. No 61/583,673, filed on Jan. 6, 2012, which is also entitled LIQUID DISPENSER PUMP, which is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates generally to liquid dispenser systems and more particularly to a liquid pump, as well as a disposable refill/replacement liquid container unit which includes such a pump. 
       BACKGROUND OF THE INVENTION 
       [0003]    Liquid dispenser systems, such as liquid soap and sanitizer dispensers, provide a user with a predetermined amount of liquid upon actuation of the dispenser. Such liquid dispenser systems often include a disposable/replacement liquid container unit which may be easily removed from the system when the liquid container is empty, to be replaced by a filled unit. 
       SUMMARY 
       [0004]    Liquid dispenser systems, pumps for use in liquid dispenser systems and disposable/replaceable liquid container units for use in liquid dispenser systems are disclosed herein. In one embodiment, a refill unit for refilling a liquid dispenser system comprises a container for holding a supply of liquid and a pump connected to the container. The pump comprises a fitment portion configured for attachment to a liquid container and a pump portion which comprises an upper valve member and a lower valve member disposed along a common longitudinal axis, such that the fitment portion and the pump portion are formed as one integral piece. 
         [0005]    In this way, a simple and economical liquid dispenser system, as well as a pump and a refill unit, are provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    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: 
           [0007]      FIG. 1  is a perspective view of a first exemplary embodiment of a liquid pump  100 ; 
           [0008]      FIG. 2  is a different perspective view of the liquid pump  100  of  FIG. 1 , attached to a liquid container  200  which is shown in partial cross-section; and 
           [0009]      FIG. 3  is a cross-sectional illustration of the liquid pump  100  of  FIG. 1 , attached to a liquid container  200  which is shown in partial cross-section. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]      FIGS. 1-3  illustrate a first exemplary embodiment of a liquid pump  100 , which in  FIGS. 2-3  is shown attached to a liquid container  200 . The liquid pump  100  and liquid container  200  together form a disposable/replaceable refill unit  300  which may be used in combination with a dispensing system (not shown). As such, the liquid pump  100  includes two locking members  102 , which in this embodiment are in the form of tabs. More generally, the locking members  102  may take any form which allows the liquid pump  100  to be connected to corresponding members in the dispensing system in a secure manner, such as a lock and key fit. In that way, in the event the liquid stored in the chamber  202  of the installed disposable refill unit  300  runs out, or the installed disposable refill unit  300  otherwise has a failure, the installed disposable refill unit  300  may be removed from the liquid dispenser system. The empty or failed disposable refill unit  300  may then be replaced with a new disposable refill unit  300  including a liquid storage chamber  202 . 
         [0011]    The dispensing system (not shown) includes a housing which contains one or more actuating members (not shown) to activate the liquid pump  100 . The liquid dispenser system 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 dispensing system may additionally have other elements, such as a foaming unit which turns the liquid received from the liquid pump  100  into a foam for dispensing to a user. 
         [0012]    The liquid container  200  of the disposable refill unit  300  forms a liquid storage chamber  202 . The liquid container  200  may be a bag made from a thin plastic material. The liquid storage chamber  202  contains a supply of a liquid within the disposable refill unit  300 . In various embodiments, the contained liquid could be for example a soap, a sanitizer, a cleanser, a disinfectant or some other liquid. In the exemplary refill unit  300 , the liquid storage chamber is formed by a flexible and collapsible pouch  204 . In other embodiments, the liquid storage chamber  202  may be formed by an uncollapsible rigid housing member, a collapsible rigid housing member, or have any other suitable configuration for containing the liquid without leaking Further, the liquid container  200  may be provided with an air inlet valve (not shown) to prevent creating a vacuum in the chamber  202  as liquid is being dispensed. The liquid container  200  may advantageously be refillable, replaceable or both refillable and replaceable. In other embodiments, the liquid container  200  within the disposable refill unit  300  may be neither refillable nor replaceable. 
         [0013]    The exemplary liquid pump  100  is a bellows pump. In other embodiments, the liquid pump may have different means of pumping liquid, such as, for example, a dome pump. The liquid pump  100  is made from any convenient material such as a plastic material; for example, a linear low-density polyethylene (LLDPE). The pump  100  has a housing  104 , a valve stem  106  and, optionally, an outlet cap  108 . The housing  104  includes a canoe fitment  110 , the locking members  102 , a bellows  112  and an outlet flange  114 , all together in one integral construction. The canoe fitment  110  of the housing  104  is received within a bottom end  206  of the container  200  to form the disposable refill unit  300 . The canoe fitment  110  may be attached to the liquid container  200  using any method, such as, for example, ultrasonic welding or heat welding, a press fit connection or a mechanical connection. 
         [0014]    In some prior systems, a canoe fitment is manufactured as a separate component from the pump mechanism, and the two are then connected together by a snap-fit or closure interface. Forming these components as one integral construction, as in the exemplary pump  100 , is simpler and less expensive than the prior art systems. 
         [0015]    The valve stem  106  is disposed within a channel  116  of the housing  104 , and may move longitudinally up and down within the channel  116  as described further below. In one embodiment, the valve stem  106  includes a valve cap  118 , an upper valve member  120  and a lower valve member  122  as one integral piece. The valve cap  118  extends out of the channel  116  and up into the liquid storage chamber  202  and has an outer periphery which is wider than the width of the channel  116 . The valve cap  118  is flexible and resilient, allowing the valve stem  106  to be pushed up through the channel  116  so that the cap  118  compresses and then expands to retain the valve stem  106  within the pump housing  104 . One or more passages  124  within the valve cap  118  permit liquid stored within the chamber  202  to flow down into an intermediate chamber  126  of the channel  116 , located within the canoe fitment  110  between the valve cap  118  and the upper valve member  120 . 
         [0016]    The upper valve member  120  of the valve stem  106  may be received within an upper valve seat  128  formed at the intersection between the canoe fitment  110  and the bellows  112 . The lower valve member  122  of the valve stem  106  may be received within a lower valve seat  130  formed at the intersection between the bellows  112  and the outlet flange  114 . Thus, the bellows  112  defines a bellows chamber  132  of the channel  116  between the two valve members  120  and  122 . The upper and lower valves open and close as the valve stem  106  reciprocates up and down within the channel  116 , as described further below. 
         [0017]    In some embodiments, such as the one in  FIGS. 2-3 , an outlet cap  108  of the liquid pump  100  is connected to the outlet flange  114  of the housing  104 . Other embodiments may not include an outlet cap  108 . When used, the bottom surface  134  of the outlet cap  108  contains one or more apertures  136  for dispensing liquid out of the liquid pump  100 . In some embodiments, the apertures  136  are simply channels leading out of the outlet cap  108 . In other embodiments, the apertures  136  may include one or more one-way check valves to prevent back flow of liquid from outside of the pump  100  back through the apertures  136 . 
         [0018]    The liquid pump  100  operates as follows.  FIG. 3  illustrates the pump  100  in a primed position. In that position, liquid is free to flow under the force of gravity from the liquid storage chamber  202  down into the intermediate chamber  126  through the passages  124  in the valve cap  118 . However, liquid within the intermediate chamber  126  is prevented from flowing into the bellows chamber  132  by the closed upper valve member  120  being received within the upper valve seat  128 . More specifically, the upper valve member  120  is made from a flexible and resilient material. The upper valve member  120  is resilient enough that it remains in the “closed” position shown in  FIG. 3 , so long as the only force acting on it is the downward force of gravity by the liquid in the intermediate chamber  126 . However, the upper valve member  120  is flexible enough so that when a suction force is applied by the bellows chamber  132  underneath the member  120 , the member  120  will separate from the upper valve seat  128  and permit liquid to flow from the intermediate chamber  126  into the bellows chamber  132 . 
         [0019]    Still describing the primed position of  FIG. 3 , the lower valve member  122  of the valve stem  106  is received within the lower valve seat  130 . In that way, a supply of liquid is trapped within the bellows chamber  132  between the two valve members  120  and  122 , and is prevented from leaking out of the refill unit  300 . The lower valve member  122  may be biased to its closed position in any number of ways. In one embodiment, the lower stem portion  138  of the valve stem  106  may be elastically stretched in the closed position of  FIG. 3 , so that the lower valve member  122  is held firmly against the lower valve seat  130 . In other embodiments, a separate biasing member (not shown) such as a coil spring may instead or in addition be used to help bias the lower valve member  122  into the closed position. The natural resiliency of the bellows  112  expanding itself to an extended position may also help to create a seal at the lower valve. The biasing mechanism(s) hold the lower valve member  122  in the closed position of  FIG. 3  at all times, except when liquid is being dispensed out of the pump  100 . 
         [0020]    Although not shown in the Figures, the liquid dispenser system in which the liquid pump  100  is situated has a pump actuator mechanism. There are many different kinds of pump actuators which may be employed in the liquid dispenser system. The pump actuator of the liquid dispenser system 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 liquid pump  100  within the liquid dispenser system. Electronic pump actuators may additionally include a motion detector to provide for a hands-free dispenser system with touchless operation. 
         [0021]    Various mechanical and/or electronic intermediate linkages connect an external actuator member to an internal actuator member (all not shown). A user operates the external actuator in order to actuate the pump  100 . As a result, the internal actuator member exerts a force on the outlet flange  114  of the liquid pump  100 , perhaps via an outlet cap  108  if used, to move it upwardly toward the liquid container  200 . The interface between the locking members  102  and the liquid dispenser system holds the canoe fitment  110  firmly in place, so that the bellows  112  contracts as the outlet flange  114  is forced upward. 
         [0022]    As the bellows  112  contracts, the upper valve member  120  remains in the closed position of  FIG. 3 , which has two consequences. First, it continues to prevent the liquid within the intermediate chamber  126  from flowing down into the bellows chamber  132 . Second, due to the contracting bellows chamber  132 , the liquid which is already disposed within the bellows chamber  132  is forced past the closed biasing of the lower valve member  122  to be dispensed. The internal actuator stops the upward movement of the outlet flange  114  when the bellows  112  reaches a fully contracted position, or has contracted far enough to dispense a desired amount of liquid. 
         [0023]    When a desired amount of liquid has been dispensed, the internal actuator stops the upward movement of the outlet flange  114 . At that time, the outlet flange  114  is free to move downwardly back to the primed position shown in  FIG. 3 . Such movement may occur due to the natural resiliency of the bellows  112  extending to that position, or under the forceful direction of the internal actuator, or by a separate biasing member such as a coil spring, or some other means. 
         [0024]    As the bellows  112  expands, a vacuum suction force is generated within the bellows chamber  132  by the closed lower valve member  122 . That force is sufficient to overcome the cracking pressure or resiliency of the upper valve member  120  and separate it from the upper valve seat  128 . Thus, during the downward stroke, liquid passes from the intermediate chamber  126  down into the bellows chamber  132 . Once the downward stroke ends, returning the pump  100  to the primed configuration of  FIG. 3 , the vacuum suction force ceases. At that time, the upper valve member  120  returns to its resting and closed position shown in  FIG. 3 . Thus, the pump  100  is ready for another actuation. 
         [0025]    As just described, in the specific embodiment of  FIGS. 3 , the valve stem  106  which includes the valve cap  118 , the upper valve member  120  and the lower valve member  122  is formed of one integral construction. In an alternative embodiment (not shown), the valves may be formed by an assembly of one or more separate pieces. As one example, such a valve assembly may be comprised of two pieces, an inner valve stem  106   a  and an outer valve sheath  106   b.  The inner valve stem  106   a  includes the lower valve member  122  and the lower stem portion  138 . The outer valve stem  106   b  includes the valve cap  118 , the upper valve member  120 , and an intermediate body which has a central channel to slidably receive the lower stem portion  138 . The inner valve stem  106   a  slides up and down in the outer valve sheath  106   b  and the channel  116  to operate the pump, while the sheath  106   b  remains stationary within the channel  116 . 
         [0026]    More specifically, when the internal actuator initially moves the outer flange  114  upwardly to operate the pump, the inner valve stem  106   a  remains in place within the channel  116 . As a result, the stationary lower valve member  122  is separated from the upwardly moving lower valve seat  130 . In that way, the lower valve is opened to permit liquid to flow downwardly out of the bellows chamber  132 . If an outlet cap  108  is employed, the liquid can then exit the pump through the apertures  136  in the bottom surface  134  of the outlet cap  108 . 
         [0027]    Eventually, the outer flange  114  is moved far enough upwardly that the bottom surface  134  of the outlet cap  108  contacts the lower valve member  122  of the inner valve stem  106   a . Further upward movement of the outlet flange  114  continues to contract the bellows  112 , but also moves the inner valve stem  106   a  upwardly within the outer valve sheath  106   b  and the channel  116 . The lower stem portion  138  of the inner valve stem  106   a  may be short enough that its upper end always remains disposed within the outer valve sheath  106   b.  Alternatively, the lower stem portion  138  may extend upwardly out of the outer valve sheath  106   b  and into the liquid storage chamber  202 . In such a case, the valve stem  106   a  may include a seal to prevent liquid from flowing from chamber  202   a  past valve stem  106   a.    
         [0028]    When a desired amount of liquid has been dispensed, the internal actuator stops the upward movement of the outlet flange  114 , which is then free to move downwardly back to the primed position shown in  FIG. 3 . During the initial downward and expanding movement of the bellows  112 , the inner valve stem  106   a  remains in an upper position within the outer valve sheath  106   b  and the channel  116 . As a result, the stationary lower valve member  122  comes into contact with the downwardly moving lower valve seat  130 . In that way, the lower valve is closed to prevent liquid and air from flowing past the lower valve. Further downward movement of the outlet flange  114  continues to expand the bellows  112 , but also moves the inner valve stem  106   a  downwardly within the outer valve sheath  106   b  and the channel  116 , which creates a vacuum to refill bellows chamber  132 . Once the downward stroke ends, the pump  100  returns to the primed configuration of  FIG. 3 , and the pump is ready for another actuation. 
         [0029]    If an outlet cap  108  is used in conjunction with an inner valve stem  106   a  and an outer valve sheath  106   b,  the apertures  136  may be disposed outside of the periphery of the lower valve member  122 . In other embodiments using an outlet cap  108 , the apertures  136  may instead or additionally be placed in the center area of the bottom surface  134 . In such an embodiment, the valve surface of the lower valve member  122  may also have apertures, so that liquid may reach the central apertures  136  when the lower valve member  122  is contacting the bottom surface  134 . When the lower valve is closed as shown in  FIG. 3 , the apertures within the lower valve member  122  are closed off by the lower valve seat  130 . 
         [0030]    The rest position of the embodiment shown in  FIGS. 1-3  is a primed pump. In yet other alternative embodiments (not shown), the rest position may be an unprimed state, such that actuation both primes the pump and then dispenses the primed liquid. 
         [0031]    In the embodiment of  FIGS. 1-3 , the passages  124  in the valve cap  118  are wide enough that liquid is free to move from the liquid storage chamber  202  to the intermediate chamber  126  at all times. In an alternative embodiment (not shown), the passages  124  may be small enough that the surface tension of the liquid in chamber  202  prevents the liquid from flowing down into the intermediate chamber  126  by the force of gravity alone. In some such embodiments, the passages  124  may function as the upper valve, so that the upper valve member  120  may not be needed. That is, the surface tension of the liquid in the chamber  202  keeps the liquid there until the bellows  112  expands in a downward stroke, creating a vacuum suction force to overcome the surface tension. 
         [0032]    The liquid pump  100  of  FIGS. 1-3 , or any other liquid pump embodiment disclosed herein, may be manufactured in any number of ways. As one example, the housing  104  and the valve stem  106  may be separately molded from suitable plastic material(s). Then the valve stem  106  may be inserted into the channel  116  of the housing  104 , because the valve cap  118  resiliently collapses as it passes through the channel  116  and then expands when it exits the channel  116  to hold the valve stem  106  in place. Then the outlet cap  108 , if desired, may be placed on the housing  104 . 
         [0033]    The liquid pump  100  may be attached to a filled liquid container  200  in any number of ways. As one example, the pump housing  104  may be first attached to the container  200 , which is then filled through the channel  116  before the valve stem  106  is inserted. Or, the pump  100  may be manufactured entirely separately from the container  200  and then attached thereto, before filling the container with liquid from an open top end which is then welded or otherwise sealed shut. As yet another option, the liquid container  200  may be filled with liquid and then held upside-down as a completed pump assembly  100  is attached to the container at its bottom end  206 . 
         [0034]    The exemplary liquid pump  100  may allow for a simple and inexpensive replacement of the liquid supply in a liquid dispenser system. Once the supply of liquid in the liquid storage chamber  202  runs out, the now-empty disposable refill unit  300  may be replaced with a new refill unit  300  containing a supply of liquid. 
         [0035]    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. For example, in a very simple embodiment, what has been described above as a refill unit  300  for use in conjunction with a separate liquid dispensing system may instead be used alone as the entire pumping system. The locking members  102  may simply be received in a mounting bracket, and the pump  100  actuated by a user pressing his or her hand on the outlet flange  114  to dispense liquid. 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 general inventive concept.
Liquid dispenser systems, pumps for use in liquid dispenser systems, and disposable/replaceable liquid container units for use in liquid dispenser systems are disclosed. A refill unit for refilling a liquid dispenser system comprises a container for holding a supply of liquid and a pump connected to the container. The pump comprises a fitment portion configured for attachment to a liquid container, and a pump portion which comprises an upper valve member and a lower valve member disposed along a common longitudinal axis, such that the fitment portion and the pump portion are formed as one integral piece.