Patent Publication Number: US-11647872-B2

Title: Double inlet valve for enhanced pump efficiency

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. Non-Provisional application Ser. No. 16/424,832, filed on May 29, 2019, which is a continuation-in-part of U.S. Non-Provisional patent application Ser. No. 16/175,957, filed on Oct. 31, 2018, now U.S. Pat. No. 11,089,913, which claims priority to and the benefits of U.S. Provisional Application Ser. No. 62/581,820, filed on Nov. 6, 2017, all of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     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. Dispenser systems often use a pump to pump liquid from a container and into the hand of a user. 
     SUMMARY 
     An exemplary dispenser includes a housing, a container disposed in the housing for holding a liquid, a nozzle, and a pump. The pump is disposed between the container and the nozzle. The pump includes a pump inlet, a pump outlet, a pump chamber, a first check valve, and a second check valve. The pump inlet is in fluid communication with the container and the pump chamber, and the pump outlet is in fluid communication with the pump chamber and the nozzle. The pump chamber is movable between an expanded position and a compressed position. The first check valve is disposed between the container and the pump, and the first check valve has a first cracking pressure. The second check valve is disposed between the first check valve and the pump, and the second check valve has a second cracking pressure. The first cracking pressure is greater than the second cracking pressure. 
     Another exemplary dispenser includes a housing, a container disposed in the housing for holding a liquid, a nozzle, and a pump. The pump is disposed between the container and the nozzle. The pump includes a pump inlet, a pump outlet, a pump chamber, a first check valve, and a second check valve. The pump inlet is in fluid communication with the container and the pump chamber, and the pump outlet is in fluid communication with the pump chamber and the nozzle. The pump chamber is movable between an expanded position and a compressed position. The first check valve is disposed between the container and the pump, and the second check valve is disposed between the first check valve and the pump. Movement of the pump chamber from the compressed position to the expanded position causes the first check valve to move to an open position such that a portion of the liquid moves from the container past the first check valve and causes the second check valve to open such that a portion of the liquid moves from the container past the second check valve and into the pump chamber. Movement of the pump chamber from the expanded position to the compressed position causes the first check valve to maintain a closed position such that liquid is prevented from moving from the container and into the pump chamber. The movement of the pump chamber from the expanded position to the compressed position also causes the second check valve to maintain a closed position such air cannot move into and be compressed in a space between the container and the second check valve. 
     An exemplary refill unit includes a container that has a neck. A closure is connected to the neck. The refill unit includes a liquid outlet path and a first check valve is located in the liquid outlet path. The first check valve has a cracking pressure of greater than 0.5 pounds per square inch. The refill unit includes a seal located in the passage downstream of the first check valve. 
     An exemplary dispensing system includes a housing and a container for holding a liquid. A liquid outlet is located on the bottom of the container. A sealing member seals the liquid outlet, allowing the container to be lowered into and removed from a dispenser without the liquid leaking out of the container. A first check valve is in fluid communication with the liquid outlet. The first check valve having a cracking pressure of greater than 0.5 pounds per square inch. A second check valve is in fluid communication with the liquid outlet. The second check valve has a cracking pressure that is less than the cracking pressure of the first check valve. A liquid pump chamber is located downstream of the first valve and the second check valve. A liquid outlet valve is located downstream of the liquid pump chamber. A mixing chamber is located downstream of the liquid outlet valve. Liquid flows into the liquid chamber and air from an air source flows into the mixing chamber and mixes with the liquid. An outlet nozzle is located downstream of the mixing chamber. 
     An exemplary dispenser for dispensing soap, sanitizer or lotion includes a housing, a container disposed in the housing holding a soap, a sanitizer or a lotion, and a pump disposed between the container and the nozzle. The pump includes a pump inlet in fluid communication with the container. A pump chamber is in fluid communication with the pump inlet and the pump outlet. The pump chamber is movable between an expanded position and a compressed position. A first check valve is disposed between the container and the pump. The first check valve has a cracking pressure of greater than about 0.5 psi. A second check valve is disposed between the first check valve and the pump. The second check valve having a cracking pressure that is less than about 0.5 psi. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional/schematic view of an exemplary embodiment of a dispenser; 
         FIG.  2    is a partial cross-sectional view of another exemplary embodiment of a portion of a dispenser; 
         FIG.  3    is a simplified schematic view of an exemplary embodiment of a dispenser; 
         FIG.  4    is a cross-sectional view of an exemplary embodiment of a refill unit for the exemplary embodiment of a dispenser having double inlet valves; 
         FIG.  5    is cross sectional view of an exemplary embodiment of a portion of a dispenser having double inlet valves for receiving the refill unit of  FIG.  4   ; 
         FIG.  6    is a cross-sectional view of the refill unit of  FIG.  4    in the dispenser of  FIG.  5   ; 
         FIG.  7    is a cross-sectional view of an exemplary embodiment of a refill unit for the exemplary embodiment of a dispenser of  FIG.  8   ; and 
         FIG.  8    is cross sectional view of an exemplary embodiment of a dispenser having for receiving the refill unit of  FIG.  7   . 
     
    
    
     DETAILED DESCRIPTION 
     The Detailed Description describes exemplary embodiments of the invention and is not intended to limit the scope of the claims in any way. Indeed, the invention is broader than and unlimited by the exemplary embodiments, and the terms used in the claims have their full ordinary meaning. Features and components of one exemplary embodiment may be incorporated into the other exemplary embodiments. Inventions within the scope of this application may include additional features, or may have less features, than those shown in the exemplary embodiments. 
       FIG.  1    illustrates an exemplary dispenser  100  having a housing  102 , a container  104  for holding a liquid, a pump  108 , a first check valve  120 , a second check valve  122 , and a dispenser outlet  110 . The first check valve  120 , a second check valve  122  are located upstream of the liquid inlet of the pump  108 . The pump  108  is configured to pump the liquid from the container  104  through the outlet  110 . In some embodiments, the liquid can be, for example, soap, a concentrated soap, a sanitizer, a lotion, a moisturizer or the like. The pump  108  may be, for example, a displacement pump, such as, for example, a piston pump, a diaphragm pump, a rotary pump, or the like. In certain embodiments, the pump  108  may be a sequentially activated multi-diaphragm foam pump. Exemplary embodiments of sequentially activated multi-diaphragm pumps are shown and disclosed in: U.S. Non-Provisional application Ser. No. 15/429,389 filed on Feb. 10, 2017 and titled HIGH QUALITY NON-AEROSOL HAND SANITIZING FOAM; U.S. Non-Provisional application Ser. No. 15/369,007 filed on Dec. 5, 2016 and titled SEQUENTIALLY ACTIVATED MULTI-DIAPHRAGM FOAM PUMPS, REFILL UNITS AND DISPENSER SYSTEMS; U.S. Non-Provisional patent application Ser. No. 15/355,112 filed on Nov. 18, 2016 and titled SEQUENTIALLY ACTIVATED MULTI-DIAPHRAGM FOAM PUMPS, REFILL UNITS AND DISPENSER SYSTEMS; U.S. Non-Provisional application Ser. No. 15/350,190 filed on Nov. 14, 2016 and titled IMPROVED FOAMING CARTRIDGE; U.S. Non-Provisional application Ser. Ser. No. 15/356,795 filed on Nov. 21, 2016 and titled FOAM DISPENSING SYSTEMS, PUMPS AND REFILL UNITS HAVING HIGH AIR TO LIQUID RATIOS; and U.S. Non-Provisional application Ser. No. 15/480,711 filed on Apr. 6, 2017 and titled FOAM DISPENSING SYSTEMS, PUMPS AND REFILL UNITS HAVING HIGH AIR TO LIQUID RATIOS; each of which are incorporated herein in their entirety. 
     In some exemplary embodiments, the pump  108  may be a foam pump that includes a liquid pump  109  and an air pump  107 . In some embodiments, the air pump and liquid pump portions are integrated into a single pump. In some embodiments, the pump  108  is a split pump and the liquid pump portion is connected to the container as a single unit that may be replaced. In an exemplary embodiment, the liquid pump portion separates from the air pump portion, which remains with the housing. Accordingly, as used herein, pump  108  may be a liquid pump or a foam pump and may have many different configurations and should not be limited to the illustrated examples. 
     In some exemplary embodiments, the dispenser  100  may include a foam cartridge (not shown). In certain of these exemplary embodiments, a liquid pump  109  pumps liquid from the container into a mixing chamber (not shown) and the air pump  107  pumps air into the mixing chamber (not shown) to mix with the liquid, and the liquid-air mixture travels through the foam cartridge to create a rich foam. Exemplary embodiments of foam pumps are shown and described in, U.S. Pat. No. 7,303,099 titled Stepped Pump Foam Dispenser; U.S. Pat. No. 8,002,150 titled Split Engagement Flange for Soap Piston; U.S. Pat. No. 8,091,739 titled Engagement Flange for Fluid Dispenser Pump Piston; U.S. Pat. No. 8,113,388 titled Engagement Flange for Removable Dispenser Cartridge; U.S. Pat. No. 8,272,539, Angled Slot Foam Dispenser; U.S. Pat. No. 8,272,540 titled Split Engagement Flange for Soap Dispenser Pump Piston; U.S. Pat. No. 8,464,912 titled Split Engagement Flange for Soap Dispenser Pump Piston; U.S. Pat. No. 8,360,286 titled Draw Back Push Pump; U.S. Provisional Pat. Ser. No. 62/293,931 titled High Quality Non-Aerosol Hand Sanitizing Foam; U.S. Provisional Pat. Application Ser. No. 62/257,008 titled Sequentially Activated Multi-Diaphragm Foam Pumps, Refill Units and Dispenser Systems; U.S. Pat. No. 8,172,555 titled Diaphragm Foam Pump; U.S. 2008/0,277,421 titled Gear Pump and Foam Dispenser, all of which are incorporated herein by reference in their entirety. These exemplary foam pumps may be converted to liquid pumps by removing the air pump components. Exemplary embodiments of foam cartridges  134  are shown and described in U.S. Publication No. 2014/0367419 titled Foam Cartridges, Pump, Refill Units and Foam Dispensers Utilizing The Same, which is incorporated herein by reference in its entirety. 
     In various embodiments, the dispenser  100  is a “touch free” dispenser and includes an actuator  114  that activates the pump  108  to pump liquid from the container  104  and out of the nozzle  110  of the dispenser  100 . Exemplary touch-fee dispensers are shown and described in U.S. Pat. No. 7,837,066 titled Electronically Keyed Dispensing System And Related Methods Utilizing Near Field Response; U.S. Pat. No. 9,172,266 title Power Systems For Touch Free Dispensers and Refill Units Containing a Power Source; U.S. Pat. No. 7,909,209 titled Apparatus for Hands-Free Dispensing of a Measured Quantity of Material; U.S. Pat. No. 7,611,030 titled Apparatus for Hans-Free Dispensing of a Measured Quantity of Material; U.S. Pat. No. 7,621,426 titled Electronically Keyed Dispensing Systems and Related Methods Utilizing Near Field Response; and U.S. Pat. No. 8,960,498 titled Touch-Free Dispenser with Single Cell Operation and Battery Banking; all which are incorporated herein by reference. In embodiments that include a touch-free feature, the dispenser  100  may include a power source (not shown), a sensor (not shown), a controller (not shown), and a motor (not shown). The power source is in electrical communication with and provides power to the sensor, controller, and motor. The power source may be an internal power source, such as, for example, one or more batteries or an external power source, such as, for example, solar cells, or a conventional 120 VAC power supply. In some embodiments, a multiple power supplies are included, such as, for example, batteries and solar cells. 
     In various embodiments, the dispenser is a manual dispenser. In such embodiments, the actuator  114  may require manual activation, such as, for example, a user engages a push bar, a user engages a foot pedal, a pushbutton, or the like. In some embodiments that require manual activation, a push bar (not shown) is mechanically coupled to the actuator  114  and, when a user engages the push bar, the actuator  114  causes liquid from the container  104  to be pumped through the nozzle  110  of the dispenser  100 . 
     Still referring to  FIG.  1   , an exemplary embodiment of a pump  108  includes a pump inlet  112 , a pump outlet  116 , and a pump chamber  118 . The pump inlet  112  is in fluid communication with the container  104  such that the pump inlet can receive liquid from the container  104 . The pump chamber  118  is in fluid communication with the pump inlet  112  such that the pump chamber can receive liquid from the container  104  through the pump inlet  122 . The pump outlet  116  is in fluid communication with the pump chamber  118  and with the nozzle  110  such that the pump  108  can pump liquid from the pump chamber through the pump outlet  116  and the nozzle  110 . In certain embodiments, the pump  108  is a positive displacement pump such that movement of the pump chamber  118  between an expanded position and a compressed position causes the pump to pump liquid through the nozzle  110  of the dispenser  100  and to move liquid from the container and into the pump chamber. In certain embodiments, the pump chamber  118  has a small volume. In certain embodiments, the volume of pump chamber  118  is between about 0.2 cc and about 0.5 cc when the pump chamber is in the expanded position. 
     The dispenser  100  includes a first check valve  120  and a second check valve  122 . Both the first check valve  120  and the second check valve  122  are located in-line between the container  104  and the pump  108 . The first check valve  120  is a normally closed valve and it prevents liquid from entering the pump chamber  118  when the first check valve is in a closed position. The first check valve  120  also prevents fluid from flowing from the pump  108  back up into the container  104 . First check valve  120  moves to an open position when a sufficient cracking pressure is present between the pump  108  and the first check valve  120 . Movement of the first check valve  120  from the closed position to an open position allows liquid to flow from the container  104 , into the area  121  between the first check valve  120  and the second check valve  122  and past first check valve  120  into pump chamber  118 . Movement of the first check valve  120  from the open position back to the closed position prevents the liquid in the container  104  from entering the pump chamber  118 . In various embodiments, the first check valve  120  is a high flow valve that is configured to prevent static drip of liquid from the container  104  through the pump  108  when the first check valve  120  is in the closed position. The first check valve  120  may be, for example, a ball and spring valve, a mushroom valve, a flapper valve, and the like. In some embodiments, first check valve  120  has a cracking pressure of at least about 0.5 psi. In some embodiments, first check valve  120  is a slow reacting check valve and is configured to hold back head pressure from the container. 
     The second check valve  122  is disposed between the first check valve  120  and the pump  108 . In certain embodiments, the second check valve  122  is disposed adjacent to the pump chamber  118  of the pump  108 . The second check valve  122  is configured to limit the volume of the pump chamber. In some embodiments, the limited volume prevents air from being compressed in the area between the container  104  and the pump  108  which tends to prevent or inhibit upstream vacuum pressure, which may occur during, for example, priming and use of the dispenser  100 . The second check valve  122  is moved to an open position by vacuum pressure created in the pump chamber  118 . Movement of the second check valve  122  from the closed position to the open position allows liquid to flow from the container  104 , past the first check valve  120  and into the pump chamber  118 , and movement of the second check valve  122  from the open position to the closed position prevents air or liquid from flowing from the pump chamber  118  back towards the container  104 . 
     Without second check valve  122 , when a small pump chamber  118  is used, compression and expansion of the pump chamber  118  may cause compression/decompression of air between the pump chamber  118  and first check valve  120  without opening the first check valve  120  thereby resulting in a failure to prime pump chamber  118 . In certain embodiments, the second check valve  122  is a high flow, fast acting valve. In some embodiments, second check valve  122  has minimal cracking pressure. In some embodiments, the cracking pressure is between about 0 and about 2 psi. Second check valve  122  is fast acting and in certain embodiments closes in less than about 0.1 second. The second check valve  122  may be, for example, an umbrella valve, a duckbill valve, a flapper valve, and the like. In certain embodiments, the second check valve  122  is a normally-open valve. In alternative embodiments, the second check valve  122  is a normally-closed valve. The first check valve  120  has a greater cracking pressure than the second check valve  122 . 
     To operate the dispenser  100 , a user activates the pump  108  using the actuator  114 , which causes liquid to move from the pump chamber  118 , through the nozzle  110 , and into a hand of the user. In certain embodiments, the pump  108  includes a liquid pump portion  109  (that includes the liquid pump chamber  118 ) and an air pump portion  107 . In these embodiments, the liquid pump portion  109  pumps liquid from the container  104 , the air pump portion  107  pumps air, and the liquid and air mix to form a foamy mixture. In alternative embodiments, the dispenser  100  is a liquid dispenser and pump  108  that only includes a liquid pump portion  109 . 
     The activation of the pump  108  causes the pump chamber  118  to move from an expanded position to a compressed position. When the pump chamber  118  compresses, check valve  122  closes preventing fluid from flowing into the space between check valve  120  and check valve  122 . This movement from the expanded position to the compressed position forces liquid in the pump chamber  118  to move through the pump outlet  116  and out a nozzle  110  of the dispenser. During this movement of the pump chamber  118  from the expanded to the compressed position, the second check valve  122  closes very fast and maintains a closed position preventing air in the passage between the container  104  and the pump chamber  118  from compressing/uncompressing thus preventing the pump  108  from operating properly. After the liquid is dispensed through the nozzle  110 , the pump chamber  118  moves back to an expanded position, which creates a negative pressure in the pump chamber  118 . This negative pressure creates a vacuum pressure that causes the first check valve  120  and the second check valve  122  to move from a closed position to an open position. The movement of the first check valve  120  and second check valve  120  to the open position allows liquid from the container  104  to flow past the first and second check valves  120 ,  122 , through the pump inlet  112  and into the pump chamber  118 . The second check valve  122  must be fast acting and is advantageous because without it, air being compressed between the container  104  and the pump  108  may prevent the pump chamber  118  from being sufficiently filled with liquid from the container  104  during operation of pump  108 , and in particularly during priming of the pump  108 , which would cause the pump  108  to be less efficient or not work at all. 
     Referring to  FIG.  2   , another exemplary embodiment of a double acting valve portion of a dispenser  200  includes an inlet  204  that is connected to a container (not shown), a pump  208 , a first check valve  220 , and a second check valve  222 . The pump  208  includes a pump inlet  212 , a pump outlet (not shown), and a pump chamber  218 . The pump chamber  218  is movable between an expanded position and a compressed position. In certain embodiments, the pump chamber  218  is a small pump chamber. In certain embodiments, pump chamber  218  has a volume between about 0.2 cc and about 0.5 cc when the pump chamber is in the expanded position. 
     The first check valve  220  and the second check valve  222  are disposed between the inlet  204  from the container and the pump  208 . The first check valve  220  includes an inlet  230 , an outlet  232 , a ball  226 , and a biasing member  228  (e.g., a spring). The first check valve  220  is movable between an open position and a closed position. The first check  220  valve is in the closed position when the ball  226  engages the seal  231  of inlet  230 , and the first check valve  220  is in the open position when the ball  226  is moved away from the seal  231  in the direction D allowing fluid flow. In certain embodiments, the first check valve  220  is a normally closed valve, in which the biasing member  228  exerts a force on the ball  226  in the direction Z that causes the first check valve  220  to maintain the closed position. When the first check valve  220  is in the closed position, liquid from the inlet  204  is prevented from moving through the inlet  230  and the outlet  232  of the first check valve  220 . In some embodiments, first check valve  220  has a cracking pressure that is greater than the head pressure in the container. The first check valve  220  moves to an open position when sufficient vacuum pressure is developed in the system downstream of first check valve  220 . Movement of the ball in the direction D moves the first check valve  220  to the open position and allows liquid from the inlet  204  to move through the check valve inlet  230  and the outlet  232  of the first check valve  220 , through the second check valve  222 , and into chamber  218  of the pump  208 . In certain embodiments, the first check valve  220  is a high flow valve that is configured to prevent static drip of liquid from the inlet  204  into the pump  208  when the first check valve  220  is in the closed position. 
     The second check valve  222  is disposed between the first check valve  220  and the pump  208 . In certain embodiments, the second check valve  222  is disposed adjacent to the pump chamber  218  of the pump  208 . The second check valve  222  is configured to prevent air from being compressed between the pump  208  and the first check valve  220  during priming and use of the dispenser  200 . Dispensers not having the second check valve  222  may have air being compressed/uncompressed in a space between (e.g., space  240  of the first check valve  220 ) that is between the inlet  230  and the pump  208 . The second check valve  222  prevents air from being compressed/uncompressed in space  240 . Movement of the second check valve  222  from the closed position to the open position allows liquid to flow from the container (not shown), through first check valve  220  and into the pump chamber  218 , and movement of the second check valve  222  from the open position to the closed position prevents fluid from flowing past the second check valve  22  toward the container. It also limits the volume of the pump chamber  218  and prevents air from being compressed/uncompressed between the inlet  230  and the pump  208 . In certain embodiments, the second check valve  222  is a high flow, fast acting valve. The second check valve  222  can be, for example, an umbrella valve, a duckbill valve, a flapper valve, or the like. In certain embodiments, the second check valve  222  is a normally-open valve. In alternative embodiments, the second check valve  222  is a normally-closed valve. In certain embodiments, the second check valve  222  has a minimal cracking pressure, such that pressure from the movement of the liquid causes the second check valve to move to an open position. 
     In certain embodiments, the first check valve  220  has a greater cracking pressure than the second check valve  222 . In various embodiments, the first check valve  220  can have a cracking pressure between about 0.5 psi and about 3 psi. The second check valve  222  can have a cracking pressure between about 0 psi and about 2 psi. 
     To operate the dispenser  200 , a user activates the pump  208 , which causes the pump chamber  218  to move from an expanded position to a compressed position. This movement from the expanded position to the compressed position forces liquid in the pump chamber  218  to move through the pump outlet and into a hand of the user. During this movement of the pump chamber  118  from the expanded to the compressed position, the second check valve  222  maintains a closed position. After the liquid is moved through the pump outlet  216 , the pump chamber  218  moves back to the expanded position, which creates a vacuum pressure in the pump chamber  218 . This vacuum pressure creates a suction that causes the ball  226  of the first check valve  220  to move in the direction D, which causes the first check valve  220  to be in an open position, and allows liquid to flow past the second check valve  222  and enter the pump chamber  218  to prime the pump  208 . The second check valve  222  is advantageous because air entering the pump chamber  218  during priming of the pump  208  may prevent the pump chamber  218  from being sufficiently filled with liquid from the inlet  204 , which would cause the pump  208  to be less efficient or not work at all. 
     The first check valve  220  remains in the open position until there is no longer a vacuum pressure in the pump chamber  218  that exceeds the cracking pressure of the first check valve  220 . Once the pump chamber  218  no longer has a vacuum pressure that is higher than the cracking pressure, the biasing member  228  forces the ball  226  to move in the direction Z such that the first check valve  220  is in a closed position. When the first check valve  220  is in the closed position, the liquid from the inlet  204  is prevented from entering the chamber  218  of the pump  208 . The pump  208  is in a primed position when the pump chamber  218  is filled with liquid, and the first check valve  220  is in the closed position. After the pump  208  is in the primed position, the dispenser  200  is ready for use by a user, and the cycle for operating the dispenser  200  described above is used to dispense liquid from the dispenser. 
     The exemplary embodiments of the pumps, first check valves, and second check valves described herein can be part of a replaceable refill unit for a dispenser, or can be fixed to the housing of a dispenser. In addition, the exemplary first and second check valves described herein can be disposed within the housing of the pump, or can be separate from the pump. 
       FIGS.  3 - 8    are additional embodiments of dispenser systems having two inlet valves and the inlet valves may have any of the characteristics identified above. The inlet valves may be referred to herein as one-way valves, or one way-check valves.  FIG.  3    is a simplified schematic view of an exemplary embodiment of a dispenser  300 . Dispenser  300  includes a housing  302 . In this exemplary embodiment, housing  302  surrounds container  320  when the dispenser  300  is in use. In some embodiments, housing  302  only partially surrounds container  302 . Container  302  is removable from dispenser  302 . Container  302  includes a sealing member  322 . In some embodiments, sealing member  322  is a seal that is broken by liquid inlet conduit  330  when container  302  is inserted into dispenser  300 . In some embodiments, sealing member  322  “reseals” container  302  when container  302  is removed from dispenser  300 . Thus, when container  302  is removed from dispenser  300 , fluid inside of container  302  is prevented from draining out of container  302 . In some embodiments, sealing member  322  is a valve, such as a slit valve, a displacement valve, a flap valve, or the like. 
     Dispenser system  300  includes a first check valve  334 . First check valve  324  is in fluid communication with liquid inlet conduit  330 . First check valve  324  is a one-way valve. In some embodiments, first check valve  324  is a ball and spring valve. First check valve  324  has a cracking pressure that is sufficient to hold back head pressure in container  330  when container  330  is connected to dispenser  300 . In some embodiments, first check valve  334  has a cracking pressure of greater than or equal to 0.5 pounds per square inch (“psi”). In some embodiments, first check valve  334  has a cracking pressure of greater than or equal to 1.0 psi. In some embodiments, first check valve  334  has a cracking pressure of between about 0.5 psi and about 4 psi. In some embodiments, first check valve  334  has a cracking pressure of between about 0.5 psi and about 3 psi. In some embodiments, first check valve  334  has a cracking pressure of between about 0.75 psi and about 2 psi. In some embodiments, first check valve  334  has a cracking pressure of between about 0.75 psi and about 1.25 psi. In some embodiments, first check valve  334  has a cracking pressure of about 1 psi. 
     Liquid conduit  336  places first check valve  334  in fluid communication with second check valve  338  and liquid pump chamber  340 . Preferably, second check valve  338  has a cracking pressure of less than first check valve  334 . In some embodiments, the cracking pressure of second check valve  338  is less than 2 psi. In some embodiments, the cracking pressure of second check valve  338  is less than 2 psi. In some embodiments, the cracking pressure of second check valve  338  is less than 1.5 psi. In some embodiments, the cracking pressure of second check valve  338  is less than 1 psi. In some embodiments, the cracking pressure of second check valve  338  is less than 0.5 psi. In some embodiments, the cracking pressure of second check valve  338  is about 0.0 psi. In some embodiments, the cracking pressure of second check valve  338  is between 0 and 2 psi. In some embodiments, the cracking pressure of second check valve  338  is between 0 and 1 psi. In some embodiments, the cracking pressure of second check valve  338  is between 0 and 0.5 psi. 
     In some embodiments, second check valve  338  is a fast acting valve and its actuation rate is faster than first check valve  334 . In some embodiments, second check valve  338  actuates two or more times for each actuation of first check valve  334 . In some embodiments, second check valve  338  actuates five or more times for each actuation of first check valve  334 . In some embodiments, second check valve  338  actuates ten or more times for each actuation of first check valve  334 . In some embodiments, second check valve  338  actuates twenty or more times for each actuation of first check valve  334 . 
     Liquid pump chamber  340  is in pump  341 . Pump  341  is operated by motor  370 . Downstream of pump chamber  340  is a pump outlet valve  342 , a mixing chamber  356 , and outlet conduit  358 , a foaming cartridge  360 , which may container one or more foaming members (not shown), such as, for examples, one or more screens, baffles, sponges, and combinations thereof, and an outlet nozzle  362 . Pump  370  also includes an air pump chamber  352 , an air inlet valve  350 , and an air outlet valve  354 . 
     During operation, motor  370  is actuated when a dispense of fluid is desired. Actuation of motor  370  compresses and expands liquid pump chamber  340  and air pump chamber  352 . When air pump chamber  352  expands, one way air-inlet valve  350  opens allowing air to flow into the air pump chamber  352 . As air pump chamber  352  contracts, one-way check valve  350  shuts and one-way air outlet valve  354  opens allowing air to flow into the mixing chamber  356 . Expansion of liquid pump chamber  342  draws liquid in through conduit  330 , through first check valve  334 , through conduit  336 , through second check valve  338  and into pump chamber  340 . Compression of liquid pump chamber  340  causes second check valve  338  to close. First check valve  334  is biased closed and closes when liquid stops flowing through liquid inlet conduit  330 , however, first check valve  334  may not close each time that second check valve  338  closes. In some embodiments, pump chamber  340  expands and contracts fast enough that liquid continues to flow through liquid inlet conduit  330 , without first check valve  334  closing each time liquid pump chamber  342  contracts and expands. In some embodiments, first check valve  338  remains open substantially the same amount of time as motor  370  operates to dispense fluid and second check valve  338  opens and shuts many times during the same time period. As liquid pump chamber  342  compresses, liquid outlet valve  342  opens and liquid flows into mixing chamber  356 , where the liquid and air mix and flow out of outlet conduit  358 , through foam generator  360  and out of outlet  262  in the form of a foam. 
       FIG.  4    is a cross-sectional view of an exemplary embodiment of a refill unit  400  for a dispenser  500 . Refill unit  400  includes a contain  402  having a neck  404 . A closure  406  is connected to neck  404 . Located in closure  406  is an optional annular channel  420  and a container vent valve  422  secured thereto. As liquid is pumped out of container  402 , vacuum pressure draws air in through air vent valve  422 . In some embodiments, the container  402  is collapsible and therefore may not require an air vent valve  422 . Air vent valve  422  is a one-way air inlet valve and accordingly, prevents liquid from flowing out of the container  402 . In addition, closure  406  includes an optional annular channel  408 . A sealing member  410  is located in annular channel  408 . Annular channel  408  and annular channel  420  are optional and other means or areas may be used to secure the optional vent valve  422  and sealing member  410 . In some embodiments, sealing member  410  is a pierceable member that is pierced by a liquid inlet conduit. Preferably, sealing member  410  is a valve that opens when contacted with a liquid inlet conduit, and closes when separated from the liquid inlet conduit. This allows the refill unit  400  to be able to be removed without leaking. Exemplary sealing members that open when contacted with liquid inlet conduit  406  and close when separated from the liquid inlet conduit  406  include, for example, a slit valve, a displacement valve, a flapper valve, and the like. 
       FIG.  5    is cross-sectional view of an exemplary embodiment of a portion of a dispenser  500  having double inlet valves for receiving refill unit  400 . Dispenser  500  includes housing  502  and a back plate  503 . Located within housing  502  is a receptacle  504  for receiving refill unit  400 . Extending up from the floor of receptacle  504  is liquid inlet conduit  506 . First check valve  510  is in fluid communication with liquid inlet conduit  506  when the refill unit  400  is inserted in dispenser  500 . In this exemplary embodiment, first check valve  510  is a ball and spring valve and includes a ball  511  and spring  512 . In addition, in this exemplary embodiment, first check valve  510  includes an o-ring seat for ball  511  to seal against. 
     Dispenser  500  includes a pump  550 . Pump  550  is operated by motor  522 . Pump  550  includes a liquid pump chamber  521  and an air pump chamber  532 . In addition, pump  550  incudes a second check valve  521  (the liquid chamber inlet valve), an air inlet check valve  533 , and a fluid outlet valve  540 . In this exemplary embodiment, fluid outlet valve  540  is the outlet valve for both the liquid pump chamber  520  and the air pump chamber  540 . In some embodiments, separate outlet valves may be used. 
     First check valve  510  is in fluid communication with liquid pump chamber  520  and second check valve  521 . First and second check valves  510 ,  521  may have any of the features/parameters/settings described herein with respect to the valves herein, including the first and second check valves and/or first and second inlet valves. Dispenser  500  further includes a mixing chamber  542 , outlet conduit  543 , a pair of foaming members  544 , such as, for example, a pair of screens. Dispenser  546  also includes an outlet  546 . 
       FIG.  6    is a cross-sectional view of the refill unit  400  in the dispenser  500 . Receptacle  504  receives the neck and closure of refill unit  400 . Liquid inlet conduit  506  extends through sealing member  410  placing the liquid inlet conduit  506  in fluid communications with the interior of container  402 . When refill unit  400  is removed from dispenser, sealing member  410  reseals itself preventing any fluid located within container  402  from flowing out of the container  402 . Dispenser  500  operates similar to the other embodiments described herein. 
       FIG.  7    is a cross-sectional view of an exemplary embodiment of a refill unit  700  for dispenser  800 . In this exemplary embodiment, many of the components are the same as those described with respect to refill unit  400  and components having the same numeric identifiers are not re-described herein. Closure  706  is connected to the neck  404  of the container. Closure  706  includes an optional vent valve  422 . Closure  706  includes an annular projection  708 . Sealing member  410  is located in annular projection  708 . In addition, first check valve  770  is secured to annular projection  708 . In this exemplary embodiment, first check valve  770  is a ball and spring valve. First check valve  770  includes a ball  772  and a spring  774 , and in addition, first check valve  770  includes an o-ring  773  that serves as a seat for ball  772 . 
       FIG.  8    is cross sectional view of an exemplary embodiment of a dispenser  800 . Dispenser  800  includes a housing  802 . This exemplary embodiment is similar to dispenser  500  described herein and similar components have been identified with the same numeric identifier. Unlike housing  502 , hosing  802  does not contain a first check valve as the first check valve is in refill unit  500 . Refill unit  700  may be inserted and removed from dispenser  800 . Dispenser  800  operates similar to the dispenser described herein. 
     While various inventive aspects, concepts and features of the inventions may be described and illustrated herein as embodied in combination with exemplary embodiments, these various aspects, concepts and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein, all such combinations and sub-combinations are intended to be within the scope of the present inventions. Still further, while various alternative embodiments as to the various aspects, concepts and features of the inventions—such as alternative materials, structures, configurations, methods, circuits, devices and components, software, hardware, control logic, alternatives as to form, fit and function, and so on—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts or features into additional embodiments and uses within the scope of the present inventions even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the inventions may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present disclosure; however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated. Moreover, while various aspects, features and concepts may be expressly identified herein as being inventive or forming part of an invention, such identification is not intended to be exclusive, but rather there may be inventive aspects, concepts and features that are fully described herein without being expressly identified as such or as part of a specific invention. Descriptions of exemplary methods or processes are not limited to inclusion of all steps as being required in all cases, nor is the order that the steps are presented to be construed as required or necessary unless expressly so stated.