Abstract:
Vented check valves, pumps and refill units for dispensers are disclosed herein. Some embodiments disclose a refill unit including a container for holding a liquid. A pump chamber is secured to the container. The pump chamber is defined at least in part by a one-way liquid inlet check valve, a one-way liquid outlet check valve and at least one wall. The volume of the pump chamber is movable between a first volume and a second volume. The inlet check valve includes a venting recess. The venting recess allows air to flow past the inlet check valve in the opposite direction of the flow of liquid into the liquid chamber.

Description:
RELATED APPLICATIONS 
     This non-provisional utility patent application claims priority to and the benefits of U.S. Provisional Patent Application Ser. No. 61/735,795 filed on Dec. 11, 2012, and entitled VENTED CHECK VALVES, PUMPS AND REFILL UNITS WITH VENTED CHECK VALVES. This application is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to check valves, pumps and refill units, and more particularly to vented check valves, pumps and refill units having vented check valves. 
     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 by use of an air pump or air compressor. Most pumps, whether liquid pumps or foam pumps have a constant volume output and to change the volume requires one to change the pump or “short-stroke” the pump. A pump is short-stroked when the actuator of the dispenser is prevented from moving its full stroke. Problems often occur with pumps when they are short-stroked. If a blocking plate is added to the dispenser actuator so that the actuator does not drive the liquid piston the full length of the pump chambers, many pumps will not prime because an air bubble remains in the liquid piston. Another problem is that air trapped in the liquid dosing chamber results in an inconsistent output. 
     SUMMARY 
     Vented check valves, pumps and refill units for dispensers are disclosed herein. Some embodiments disclose a refill unit including a container for holding a liquid. A pump chamber is secured to the container. The pump chamber is defined at least in part by a one-way liquid inlet check valve, a one-way liquid outlet check valve and at least one wall. The volume of the pump chamber is movable between a first volume and a second volume. The inlet check valve includes a venting recess. The venting recess allows air to flow past the inlet check valve in the opposite direction of the flow of liquid into the liquid chamber. 
     In some embodiments, refill units include a container for holding a liquid and a pump secured to the container. The pump includes a pump chamber and an inlet check valve located upstream of the pump chamber. The inlet check valve includes an annular seal that has a venting recess located in the annular seal. Air in the pump chamber may pass through the venting recess in the annular seal and flow back up into the container that supplies liquid to the pump. 
     Exemplary embodiments of pumps include a pump chamber defined by a one-way liquid inlet check valve, a one-way liquid outlet check valve and at least one wall. The volume of the pump chamber is movable between a first volume and a second volume. The inlet check valve includes a venting recess. The venting recess allows air to flow past the inlet check valve in the opposite direction of the flow of liquid into the liquid chamber. 
    
    
     
       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. 1A  illustrates an cross-section of an exemplary embodiment of a vented check valve; 
         FIG. 1B  illustrates a plan view of the exemplary embodiment of the vented check valve of  FIG. 1A ; 
         FIG. 2A  illustrates the exemplary embodiment of the vented check valve of  FIGS. 1A and 1B  in a pump connected to a container; wherein the pump is set up to be short-stroked and the piston is at the innermost end of its travel; 
         FIG. 2B  illustrates the exemplary embodiment of the vented check valve of  FIGS. 1A and 1B  in a pump connected to a container wherein the piston is at the outermost end of its travel; 
         FIG. 3  illustrates another exemplary embodiment of a vented check valve; and 
         FIG. 4  illustrates yet another exemplary embodiment of a vented check valve. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of check valves, pumps and refill units disclosed herein alleviate problems of air in the liquid pump chamber that prevents a liquid pump from priming when the pump is short-stroked. The exemplary embodiments of vented check valves, liquid pumps, foam pumps and refill units having vented check valves shown and described herein may be used for many applications. 
       FIG. 1A  illustrates an exemplary embodiment of a vented check valve  100 . One exemplary vented check valve  100  is made of a thermoplastic elastomer (TPE), or a Polyolefin Elastomer, such as Dow Engage® 8401. Vented check valve  100  may be used as an inlet check valve in a liquid pump. Exemplary embodiments of such liquid pumps are described in more detail below. The vented check valve  100  includes a projecting member  102  for securing the valve in position in a pump housing (not shown) and a sealing member  104 . Sealing member  104  includes one or more venting recess(es) or notch(es)  106  in the sealing member  104 . As described in more detail below, venting recess  106  provides a path for air to escape out of a pump chamber (not shown). Venting recess  106  may be a sharp notch, a rounded notch, a hole, one or more slits or the like. 
     Venting recess  106  has a recess depth  110 . Sealing member  104  has a depth  112 . In one embodiment, the sealing member  104  depth  112  is about 0.090 inches and the venting recess  106  depth  110  is about 0.025 inches. In some embodiments, recess depth  110  of venting recess  106  is less than about 20% of depth  112  of sealing member  104 . In some embodiments, recess depth  110  of venting recess  106  is less than about 30% of depth  112  of sealing member  104 . In some embodiments, recess depth  110  of venting recess  106  is less than about 40% of depth  112  of sealing member  104 . In some embodiments, recess depth  110  of venting recess  106  is less than about 50% of depth  112  of sealing member  104 . 
       FIGS. 2A and 2B  illustrate the exemplary vented check valve  100  in a refill unit  200 . Refill unit  200  includes a container  202  for holding a liquid. In some embodiments, the liquid is a foamable liquid. In such embodiments, the exemplary refill unit  200  includes a mixing chamber (not shown) and an air inlet (not shown) into the mixing chamber. In addition, an air compressor (not shown) would be included. The air compressor may be separate from the refill unit  200  or integral with the refill unit  200 . 
     Connected to container  202  is a pump housing  203 . Pump housing  203  includes a cap  204  that is securable to container  202 . Cap  204  and container  202  may be connected by a threaded connection, a snap-fit connection, a welded connection, an adhesive connection or the like. A base  205  is located within cap  204 . Base  205  includes a mounting aperture  201  for receiving and retaining vented check valve  100 . During assembly, projection  102  is forced up through aperture  201  and projection  102  retains vented valve  100  in place. In addition, base  205  includes one or more liquid inlet apertures  206 . 
     Pump housing  203  includes cylindrical wall  208  and cylindrical base  209 . Located within pump housing  203  is a liquid pump chamber  220 . A piston  232  is moveable within liquid pump chamber  220 . In one embodiment, piston  232  is hollow and has a piston head  230  located at one end. An aperture  236  in piston head  230  places the interior of piston  232  in fluid communication with the liquid pump chamber  220 . An outlet check valve  238  is located in fluid communication with the hollow interior of piston  232 , and in one embodiment is located within piston  232 . An outlet  242  is located downstream of the outlet check valve  238 . In some embodiments, a mixing chamber (not shown) and an air inlet (not shown) are included and located downstream of the outlet check valve  238 . In addition, a mix media may be located downstream of the outlet check valve  238 . Mix media may be, for example, one or more screens, baffles, sponge, porous material or the like that causes liquid and air to mix together to form a foam. Piston  232  includes annular projection  246  for engaging with an actuator (not shown) of a dispenser (not shown) for operating pump  203 . 
     The vented check valve may be used in many types of conventional pumps used today for the dispensing of liquid soap and sanitizers. Other exemplary embodiments of liquid and foam pumps that may be used with the exemplary embodiments of vented check valves include U.S. patent application Ser. No. 13/208,076, titled Split Body Pumps for Foam Dispensers and Refill Units, filed on Aug. 11, 2011; U.S. Provisional Patent Application No. 61/692,290, titled Horizontal Pumps, Refill Units and Foam Dispensers With Integral Air Compressors, filed on Aug. 23, 2012; and U.S. Provisional Patent Application No. 61/695,140, titled Horizontal Pumps, Refill Units and Foam Dispensers, filed on Aug. 30, 2012, each of which is incorporated herein by reference. 
     Similarly, the vented check valves may be used in many dispensers where it is desirable to short-stroke the dispenser. The dispensers may be designed to be short-stroked, may be modified to be short-stroked in the factory or may be modified to be short-stroked in the field. Exemplary embodiments of dispensers that may utilize the exemplary embodiments of vented check valves if modified to be short-stroked may include, for example, U.S. Pat. No. 7,086,567, titled Wall-Mounted Dispenser Assembly With Transparent Window, filed on Jul. 25, 2002; and U.S. Patent Publication No. 2010/0059550, titled Pump Having a Flexible Mechanism for Engagement With a Dispenser, filed on Sep. 11, 2009, each of which is incorporated herein by reference. 
     Some prior art pumps fail to prime when the pump is purposely short-stroked to provide a reduce output because air is compressible. Accordingly, if a normal inlet check valve (not shown) is used as a piston travels to its innermost position (which is short of traveling the entire length of the liquid pump chamber) the air compresses. Often the air pressure fails to build up high enough to reach the cracking pressure of the outlet check valve. If it does build enough pressure to open the outlet check valve, some air may escape out of outlet nozzle; however, once the pressure falls below the cracking pressure of outlet check valve, the outlet check valve closes leaving pressurized air in the pump chamber. In addition, with a normal inlet check valve (not shown), as the piston moves outward, the compressed air expands and a vacuum is created in the pump chamber. A normal inlet check valve (not shown) does not open until a vacuum pressure builds up that is greater than the cracking pressure of the normal inlet check valve (not shown). In many cases, although the vacuum pressure increases while the piston moves outward, the vacuum pressure does not increase beyond the cracking pressure of the normal inlet check valve and the valve does not prime. 
     The refill unit  200  of  FIG. 2A  illustrates the piston  232  located at its innermost position when refill unit  200  is installed in a dispenser (not shown) that is set up to short-stroke the pump  203  so that the dispenser has a smaller output dose. In some embodiments, the recess  106  of inlet check valve  100  forms an opening between the inside wall  207  of cylindrical wall  208  and seal  104  of inlet check valve  100 . Thus, vented inlet check valve  100  becomes essentially a normally open valve. Accordingly, liquid may flow into the pump chamber  220  through recess  106  and air may flow out of pump chamber  220  and up into container  202 . 
     In some embodiments, recess  106  does not form an “opening” between the inside wall  207  and seal  104 ; however, it does form a weakened area, or an area that has a lower cracking pressure. In such embodiments, the lower cracking pressure in that area allows air trapped in liquid pump chamber  220  to be forced out of the liquid pump chamber  220  without significantly raising the air pressure in the liquid pump chamber  220 . Accordingly, when piston  232  is moved toward its outermost position, shown in  FIG. 2B , liquid is drawn into liquid chamber  220 . 
     When piston  232  moves back to the position shown in  FIG. 2A  and compresses liquid chamber  220 , air may flow up into container  202  until the air has been evacuated from the liquid pump chamber  220 , sufficient pressure builds to seal of inlet valve  100  against inner wall  207 , or liquid contacts the sealing member  104  and causes the sealing member  104  to seal against inner wall  207 . As the liquid pump chamber  220  continues to compress, liquid is forced from liquid pump chamber  220  through opening  236  and through the hollow interior of piston  232  past outlet check valve  238  and out of outlet nozzle  242 . 
       FIG. 3  illustrates another exemplary embodiment of a vented inlet check valve  300 . Inlet check valve  300  includes a projection  302  for securing inlet check valve  300  to a housing (not shown). Inlet check valve  300  includes a sealing member  304 . Sealing member  304  has a venting recess  306 . Venting recess  306  has an arcuate shape. Additional shapes for venting recesses are contemplated herein, such as, for example, a sharp notch as shown in  FIGS. 1A-2B , a plurality of slits, a u-shape cutout or the like. The venting recess  306  forms a passageway that may be normally open when the inlet check valve is not under pressure from the pump chamber, or forms a weakened cracking pressure in that area for the passage of air that seals to prevent liquid from flowing past. 
       FIG. 4  illustrates yet another exemplary embodiment of inlet check valve  400 . Inlet check valve  400  is illustrated in a pump housing  450 . Check valve  400  has an interference fit with housing  450  (which is exaggerated in  FIG. 4  and not shown to scale for illustrative purposes). Sealing member  404  has a contact depth  430  with wall  450 . Vented recess  406  has a recess depth  420 . In one embodiment, sealing member  404  has a contact depth  430  of about 0.011 inches and venting recess  406  depth  420  of about 0.025 inches. In some embodiments, recess depth  420  is greater than about 100% of contact depth  430 . In some embodiments, recess depth  420  is greater than about 130% of contact depth  430 . In some embodiments, recess depth  420  is greater than about 140% of contact depth  430 . In some embodiments, recess depth  420  is greater than about 150% of contact depth  430 . In some embodiments, recess depth  420  is greater than about 200% of contact depth  430 . 
     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. 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 applicant&#39;s general inventive concept.