Patent Description:
The present invention provides a dispenser according to claim <NUM>.

A dispenser according to the invention includes a housing, an inverted container disposed in the housing, an outlet nozzle, a pump, a first check valve, and a second check valve. The container holds a fluid. The pump is disposed between the container and the outlet nozzle. The pump includes a pump inlet in fluid communication with the container, a pump outlet in fluid communication with the outlet nozzle, and a pump chamber in fluid communication with the pump inlet and the pump outlet. The pump chamber is movable between an expanded position and a compressed position. The first check valve is disposed between the pump and the outlet nozzle, and the first check valve has a first cracking pressure. The second check valve is disposed between the first check valve and the outlet nozzle, and the second check valve has a second cracking pressure. The second cracking pressure of the second check valve is greater than the first cracking pressure of the first check valve.

An embodiment of the claimed dispenser includes a housing, an inverted container disposed in the housing, an outlet nozzle, a pump, a first check valve, and a second check valve. The inverted container holds a liquid. The pump is disposed between the container and the outlet nozzle. The pump includes a pump inlet, a pump outlet, and a pump chamber. 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 outlet nozzle. The pump chamber is movable between an expanded position and a compressed position. The first check valve is disposed between the pump and the outlet nozzle, and the first check valve has a cracking pressure that is less than about <NUM> mbar (<NUM> psi). The second check valve is disposed between the first check valve and the outlet nozzle, and the second check valve has a cracking pressure that is greater than about <NUM> mbar (<NUM> psi).

Another not-claimed dispenser includes a housing, an actuator located within the housing, a container located within the housing, a pump, at least one fast acting outlet valve located downstream of the pump, a slow acting outlet valve located downstream of the fast acting outlet valve, and an outlet nozzle. The container carries a fluid that includes soap, lotion, or sanitizer. The pump has an inlet, at least two pump chambers, and an outlet. During a selected dispensing time, the fast acting outlet valve cycles open and closed at least two times for every time the slow acting outlet valve cycles open and closed.

Another not-claimed dispenser includes a housing, an actuator located within the housing, a holder for holding a container, a pump, at least two outlet valves in series, and an outlet nozzle. The container holds a soap, sanitizer, or lotion. The pump has an inlet, at least one pump chamber, and an outlet. The at least two outlet valves are located downstream of the pump. During a selected dispensing time, at least one of the two outlet valves cycles open and closed at least two times for every time a second of the two outlet valves cycles open and closed.

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. Embodiments within the scope of the claims may include additional features, or may have less features, than those shown in the exemplary embodiments.

<FIG> illustrates dispenser <NUM> having a housing <NUM>, a container <NUM> for holding a liquid, a pump <NUM>, a first check valve <NUM>, a second check valve <NUM>, and a dispenser outlet <NUM>. As shown in the illustrated embodiment, the dispenser is an inverted dispenser. The pump <NUM> is configured to pump the liquid from the container <NUM> through the outlet <NUM> and into the hand of a user. The liquid can be, for example, soap, a concentrated soap, a sanitizer, a lotion, a moisturizer or the like. The pump <NUM> 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 <NUM> may be a sequentially activated multi-diaphragm pump. Exemplary embodiments of sequentially activated multi-diaphragm pumps are shown and disclosed in: <CIT> and titled HIGH QUALITY NON-AEROSOL HAND SANITIZING FOAM; <CIT> and titled SEQUENTIALLY ACTIVATED MULTI-DIAPHRAGM FOAM PUMPS, REFILL UNITS AND DISPENSER SYSTEMS; <CIT> and titled SEQUENTIALLY ACTIVATED MULTI-DIAPHRAGM FOAM PUMPS, REFILL UNITS AND DISPENSER SYSTEMS; <CIT> and titled IMPROVED FOAMING CARTRIDGE; <CIT> and titled FOAM DISPENSING SYSTEMS, PUMPS AND REFILL UNITS HAVING HIGH AIR TO LIQUID RATIOS; and <CIT> and titled FOAM DISPENSING SYSTEMS, PUMPS AND REFILL UNITS HAVING HIGH AIR TO LIQUID RATIOS.

In various embodiments, the dispenser <NUM> is a "touch free" dispenser and includes an actuator <NUM> that activates the pump <NUM> to pump liquid from the container <NUM> and out of the outlet nozzle <NUM> of the dispenser <NUM>. In some embodiments, the liquid is combined with air and dispensed as a foam. Exemplary touch-fee dispensers are shown and described in <CIT> titled Electronically Keyed Dispensing System And Related Methods Utilizing Near Field Response; <CIT> title Power Systems For Touch Free Dispensers and Refill Units Containing a Power Source; <CIT> titled Apparatus for Hands-Free Dispensing of a Measured Quantity of Material; <CIT> titled Apparatus for Hans-Free Dispensing of a Measured Quantity of Material; <CIT> titled Electronically Keyed Dispensing Systems and Related Methods Utilizing Near Field Response; and <CIT> titled Touch-Free Dispenser with Single Cell Operation and Battery Banking. In embodiments that include a touch-free feature, the dispenser <NUM> may include a power source (not shown), a sensor (not shown) for detecting the presence of a hand, a controller (not shown), and a motor (not shown), which are all known in the art. 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 <NUM> VAC power supply, or combinations thereof.

In various embodiments, the dispenser is a manual dispenser. In such embodiments, the actuator <NUM> requires 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 pump <NUM> and, when a user engages the push bar, the pump causes liquid from the container <NUM> to exit the outlet nozzle <NUM> of the dispenser <NUM>.

Still referring to <FIG>, an exemplary embodiment of a pump <NUM> includes a pump inlet <NUM>, a pump outlet <NUM>, and a pump chamber <NUM>. The pump inlet <NUM> is in fluid communication with the container <NUM> such that the pump inlet receives liquid from the container <NUM>. The pump chamber <NUM> is in fluid communication with the pump inlet <NUM> such that the pump chamber <NUM> can receive liquid from the container <NUM> through the pump inlet <NUM>. The pump outlet <NUM> is in fluid communication with the pump chamber <NUM> and with the outlet nozzle <NUM> such that the pump <NUM> can pump liquid from the pump chamber <NUM> through the pump outlet <NUM> and the outlet nozzle <NUM>. In certain embodiments, the pump <NUM> is a positive displacement pump such that movement of the pump chamber <NUM> between an expanded position and a compressed position causes the pump <NUM> to pump liquid through the outlet nozzle <NUM> of the dispenser <NUM> and to move liquid from the container <NUM> and into the pump chamber <NUM>. In certain embodiments, the pump chamber <NUM> has a small volume. In certain embodiments, the volume of pump chamber <NUM> is between about <NUM> cc and about <NUM> cc when the pump chamber <NUM> is in the expanded position.

The dispenser <NUM> includes a first check valve <NUM> and a second check valve <NUM>. Both the first check valve <NUM> and the second check valve <NUM> are disposed between the pump <NUM> and the outlet nozzle <NUM>. The first check valve <NUM> may be a normally closed valve disposed adjacent to the outlet <NUM> of the pump <NUM>. In some embodiments, first check valve <NUM> may have minimal to no cracking pressure. First check valve <NUM> is a fast acting valve.

Movement of the first check valve <NUM> from the closed position to an open position allows liquid in the pump chamber <NUM> to move past the first check valve <NUM> and into the area <NUM> between the first check valve <NUM> and the second check valve <NUM>. Movement of the first check valve <NUM> from the open position back to the closed position prevents fluid, i.e. air or liquid, from flowing into the pump chamber <NUM> from the area <NUM> between the first check valve <NUM> and the second check valve <NUM>.

It is advantageous to prevent air from entering the pump chamber <NUM> (during, for example, priming and use of the dispenser <NUM>) from the area between first check valve <NUM> and second check valve <NUM>, because air being compressed in the pump chamber <NUM> (and/or air in the pump chamber and the air between first check valve <NUM> and second check valve <NUM>) affects the efficiency of the pump <NUM> and/or may prevent the pump <NUM> from priming. That is, if air enters the pump chamber <NUM> from area <NUM>, during priming of the pump <NUM>, the air will occupy a portion of the volume of the pump chamber <NUM>, which will lead to less liquid, or no liquid at all, being pulled into the pump chamber <NUM>. In addition, because air is more compressible than liquid, air in the pump chamber <NUM> may readily compress and expand with expansion and compression of the pump chamber <NUM> and not pump any liquid, or pump smaller doses of liquid than desired. In some embodiments, it is preferred that the first check valve <NUM> is located as close as possible to the downstream end of the pump chamber <NUM>. The term pump outlet is used broadly herein and the first check valve <NUM> may be located in or at the opening of the pump outlet <NUM> from the pump chamber <NUM>.

In certain embodiments, the first check valve <NUM> is a high flow, fast acting valve. For example, in some embodiments, the first check valve closes in less than about <NUM> seconds. In some embodiments, upon activation of the pump <NUM> (for example, using a sequentially activated diaphragm pump), the first check valve <NUM> will move from the closed position to the open position between about <NUM> times and about <NUM> times in about <NUM> seconds, such as, for example, about <NUM> times in <NUM> seconds. In certain embodiments, first check valve <NUM> has minimal cracking pressure. For example, in some embodiments, the cracking pressure of the first check valve <NUM> is between about <NUM> mbar (<NUM> psi) and about <NUM> mbar (<NUM> psi). The first check valve <NUM> can be, for example, an umbrella valve, a duckbill valve, a flapper valve, or the like.

The second check valve <NUM> is disposed between the first check valve <NUM> and the outlet nozzle <NUM>. The second check valve <NUM> is a normally closed valve. The second check valve <NUM> is configured to prevent liquid from flowing out of the outlet nozzle <NUM> of the dispenser <NUM> when the pump <NUM> is not in operation. Movement of the second check valve <NUM> from the closed position to an open position allows fluid in area <NUM> to exit the outlet nozzle <NUM> of the dispenser <NUM> and be dispensed into the hand of a user. After the fluid stops moving past the second check valve <NUM> and through the outlet nozzle <NUM>, the second check valve <NUM> returns to the closed position, which prevents residual fluid in area <NUM> from flowing out of the dispenser <NUM> through outlet nozzle <NUM>. Accordingly, the second check valve <NUM> acts as an anti-drip mechanism. In some embodiments, the second check valve <NUM> is a slow reacting high flow check valve. For example, in some embodiments, upon activation of the pump <NUM>, the second check valve <NUM> remains in the open position for between about <NUM> seconds and about <NUM> seconds, such as about <NUM> seconds even though the first check valve <NUM> is opening and closing multiple times during the same time period. In certain embodiments, the second check valve <NUM> has a cracking pressure of <NUM> mbar (<NUM> psi) or greater, such as <NUM> mbar (<NUM> psi) or greater, such as <NUM> mbar (<NUM> psi) or greater, such as <NUM> mbar (<NUM> psi) or greater. The second check valve <NUM> can be, for example, a ball and spring valve, a mushroom valve, a flapper valve, or the like.

In the invention, the second check valve <NUM> has a greater cracking pressure than the first check valve <NUM>. In various embodiments, the second check valve <NUM> can have a cracking pressure between about <NUM> mbar (<NUM> psi) and about <NUM> mbar (<NUM> psi), and the first check valve <NUM> can have a cracking pressure between about <NUM> mbar (<NUM> psi) and about <NUM> mbar (<NUM> psi). In certain embodiments, the ratio of cracking pressure for the second check valve <NUM> to the cracking pressure for the first check valve <NUM> can be between about <NUM> to <NUM> and about <NUM> to <NUM>. In alternative embodiments, the ratio of cracking pressure for the second check valve <NUM> to the cracking pressure of the first check valve <NUM> can be greater than <NUM> to <NUM>, such as for example, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM> and <NUM> to <NUM>.

To operate the dispenser <NUM>, a user activates the pump <NUM> using the actuator <NUM>, which causes fluid to flow from the pump chamber <NUM>, through the outlet nozzle <NUM>, and into a hand of the user. Activation of the pump <NUM> causes the pump chamber <NUM> to move from an expanded position to a compressed position, which causes the fluid in the pump chamber <NUM> to travel through the pump outlet <NUM> and engage the first check valve <NUM> such that a force is applied to the first check valve that causes the first check valve <NUM> to move to an open position. That is, the force applied by the fluid creates a pressure on the first check valve <NUM> that exceeds the cracking pressure of the first check valve, which causes the first check valve <NUM> to move to the open position. Movement of the first check valve <NUM> to the open position allows the fluid to move past the first check valve <NUM> and into the area <NUM> between the first check valve <NUM> and the second check valve <NUM>. As fluid moves into the area <NUM>, the fluid engages the second check valve <NUM> and applies a force to the second check valve <NUM> that causes the second check valve <NUM> to move to an open position. That is, the force applied by the fluid (from activation of the pump <NUM>) creates a pressure on the second check valve <NUM> that exceeds the cracking pressure of the second check valve <NUM>, which causes the second check valve <NUM> to move to the open position. Movement of the second check valve <NUM> to the open position allows the fluid to move past the second check valve <NUM>, through the outlet nozzle <NUM> of the dispenser <NUM>, and into the hand of a user. The contraction of pump chamber <NUM> also causes first check valve <NUM> to rapidly close in order to prevent fluid from being drawn in from area <NUM> and forcing fluid to be drawn in from container <NUM>.

After any air from upstream of the pump chamber <NUM> exits the pump chamber <NUM>, the pump <NUM> is primed (i.e., fluid is moved from the container <NUM> and into the pump chamber <NUM>) such that another activation of the pump <NUM> causes fluid to be pumped toward the outlet nozzle <NUM> of the dispenser <NUM>. When the pump chamber <NUM> fully compresses, fluid flow stops and the force applied by the fluid on the first check valve <NUM> decreases until the pressure applied on the first check valve <NUM> is less than the cracking pressure of the first check valve, which may cause the first check valve <NUM> to return to the closed position. In some embodiments, first check valve <NUM> does not return to a closed position until a negative pressure develops in pump chamber <NUM> (i.e. the pump chamber <NUM> begins to expand). As the fluid flow stops, the force applied by the liquid on the second check valve <NUM> will decrease until the pressure applied on the second check valve <NUM> is less than the cracking pressure of the second check valve, which will cause the second check valve to return to the closed position. Expansion and contraction of the pump chamber <NUM> cause the first check valve <NUM> to close and open respectively. In some embodiments, the opening and closing of first check valve <NUM>, and hence the expansion and contraction of the pump chamber <NUM> happens fast enough that sufficient fluid flow continues through area <NUM> to keep second check valve <NUM> open. In many embodiments, there are more than one pump chambers <NUM> feeding area <NUM>. In some embodiments multiple pump chambers <NUM> are sequenced so that one pump chamber <NUM> is expanding while another pump chamber is compressing, thus helping maintain a constant flow of fluid through area <NUM> and past second check valve <NUM>.

In some embodiments, the volume of area <NUM> is greater than the volume of pump chamber <NUM>. In some embodiments, the volume of area <NUM> is two or more times the volume of pump chamber <NUM>. In some embodiments, the volume of area <NUM> is three or more times the volume of pump chamber <NUM>. In some embodiments, the volume of area <NUM> is four or more times the volume of pump chamber <NUM>. In some embodiments, the volume of area <NUM> is five or more times the volume of pump chamber <NUM>.

As the pump chamber <NUM> moves from the compressed position to the expanded position, a negative pressure is created in the pump chamber <NUM>. The negative pressure in the pump chamber <NUM> causes liquid from the container <NUM> to enter the pump chamber through the pump inlet <NUM>. In the invention, the first check valve <NUM> is advantageous because it prevents air and/or liquid in the area <NUM> from entering the pump chamber <NUM> through the pump outlet <NUM>. If air and/or residual liquid enter the pump chamber <NUM> through the pump outlet <NUM> during operation of the pump <NUM>, and, in particular, during priming of the pump, the pump <NUM> may be less efficient and possibly not prime. In the invention, the second check valve <NUM> is advantageous because it prevents residual fluid in the area <NUM> from dripping through the outlet nozzle <NUM> between activations of the pump <NUM>.

<FIG> illustrates a cross sectional view of a portion of an exemplary dispenser <NUM> having a novel outlet valve arrangement. Dispenser <NUM> includes a pump <NUM>, a first check valve <NUM>, a second check valve <NUM>, and an outlet nozzle <NUM>. The pump includes a pump inlet (not shown) that is in fluid communication with a container (not shown) of the dispenser <NUM>, a pump chamber <NUM>, and a pump outlet <NUM>. The pump <NUM> is an inverted setup, i.e. a container (not shown) full of fluid is in fluid communication with the pump chamber <NUM> and is positioned so that at least a portion of the fluid in the container is located above the pump chamber <NUM>. The pump chamber <NUM> is movable between an expanded position and a compressed position.

In certain embodiments, the pump chamber <NUM> includes a compressible portion <NUM> and a non-compressible portion <NUM>. The volume of the compressible portion <NUM> of the pump chamber <NUM> moves between an expanded volume (i.e., the volume of the pump in the expanded state) and a compressed volume when the pump chamber is in the compressed state. The volume of the non-compressible portion <NUM> of the pump chamber <NUM> remains constant. In certain embodiments, the volume of the compressible portion <NUM> is between about <NUM>% and about <NUM>% of the volume of the entire pump chamber (i.e., the volume of both the compressible portion <NUM> and the non-compressible portion <NUM>). In some embodiments, it is advantageous to have a pump chamber <NUM> that includes a compressible portion <NUM> that has a volume between <NUM>% and <NUM>% of the volume for the entire pump chamber because a positive displacement pump is more efficient if a larger portion of the volume for the pump chamber is compressible. In certain embodiments, the pump chamber <NUM> is a small pump chamber. For example, the pump chamber <NUM> can have a volume between about <NUM> cc and about <NUM> cc when the pump chamber is in the expanded position.

The first check valve <NUM> and the second check valve <NUM> are disposed between the pump <NUM> and the outlet nozzle <NUM>. The first check valve <NUM> is disposed between the pump <NUM> and the second check valve <NUM>. In certain embodiments, the first check valve <NUM> is disposed adjacent to the pump chamber <NUM> of the pump <NUM>. In some embodiments, the first check valve <NUM> is disposed a distance X away from the compressible portion <NUM> of the pump chamber <NUM>. The distance X can be, for example, between about <NUM> inches and about <NUM> inches, such as between about <NUM> inches and about <NUM> inches. In certain embodiments, the distance X can be <NUM> inches or less, such as about <NUM> inches or less, such as about <NUM> inches or less, such as about <NUM> inches or less.

In some embodiments, the first check valve <NUM> is a normally closed valve that prevents liquid from exiting the pump chamber <NUM> through the pump outlet <NUM> when the first check valve <NUM> is in a closed position. In some embodiments, first check valve <NUM> has a neutral state or has a very slight cracking pressure to open, provided that first check valve <NUM> quickly closes upon minimal vacuum pressure in pump chamber <NUM>. Movement of the first check valve <NUM> from the closed position to an open position allows liquid in the pump chamber <NUM> to move past the first check valve <NUM> and into the area <NUM> between the first check valve and the second check valve <NUM>. Movement of the first check valve <NUM> from the open position back to the closed position prevents liquid and/or air from entering the pump chamber <NUM> from area <NUM> of the pump <NUM>. It is advantageous to prevent air from entering the pump chamber <NUM> (during, for example, priming and use of the dispenser <NUM>) because air being compressed in the pump chamber <NUM> affects the efficiency of the pump <NUM>. That is, if air enters the pump chamber <NUM> during priming of the pump, the air will occupy a portion of the volume of the pump chamber, which may lead to less fluid being drawn in the pump chamber <NUM>, or simply compressing and decompressing the air in the pump chamber <NUM> resulting in the pump <NUM> not priming or taking a long period of time to prime.

In some embodiments, upon activation of the pump <NUM>, the first check valve <NUM> will rapidly move between the closed position and the open position between about <NUM> times and about <NUM> times in about <NUM> seconds, such as about <NUM> times in about <NUM> seconds. In certain embodiments, the first check valve <NUM> is a high flow, fast acting valve. For example, in some embodiments, the first check valve <NUM> closes in less than about <NUM> seconds. In certain embodiments, first check valve <NUM> has minimal cracking pressure. For example, the cracking pressure of the first check valve <NUM> is between about <NUM> mbar (<NUM> psi) and about <NUM> mbar (<NUM> psi). In the illustrated embodiment, the first check valve <NUM> is an umbrella valve. In alternative embodiments, the first check valve can be a duckbill valve, a flapper valve, or the like.

In certain embodiments, the pump <NUM> is a sequentially-activated multi-diaphragm pump that has a plurality of pump chambers (e.g., the pump chamber <NUM> described above). In some of these embodiments, a check valve (e.g., the first check valve <NUM> described above) may be disposed adjacent to each of the pump chambers such that each of the check valves is disposed between the corresponding pump chamber and the second check valve <NUM>. In other embodiments, a single check valve (i.e., the first check valve <NUM> described above) may be disposed adjacent to all of the pump chambers such that the single check valve is disposed between each of the pump chambers and the second check valve <NUM>. In the above-mentioned embodiments, the check valve(s) between the pump chambers and the second check valve <NUM> may take any form and act in any manner described herein with regard to the first check valve <NUM>. In the above-mentioned embodiments, the check valve(s) <NUM> between the pump chambers and the second check valve <NUM> may rapidly move between the closed position and the open position upon activation of the pump. For example, the check valve(s) <NUM> may move between closed position and the open position between about <NUM> times and about <NUM> times in about <NUM> seconds, such as about <NUM> times in about <NUM> seconds. In addition, in the above-mentioned embodiments, the check valve(s) may be high flow, fast acting valves that close in less than about <NUM> seconds. The check valve(s) also have a minimal cracking pressure, such as, for example, between about <NUM> mbar (<NUM> psi) and about <NUM> mbar (<NUM> psi). The check valve(s) may be an umbrella valve, a duckbill valve, a flapper valve, or the like.

In this exemplary embodiment, the second check valve <NUM> includes a mushroom member <NUM> and a biasing member <NUM> (e.g., a spring). Other check valves with similar properties may be used, such as, for example, a spring and ball valve. The second check valve <NUM> is movable between an open position and a closed position. The second check <NUM> valve is in the closed position when the mushroom member <NUM> engages an sealing surface <NUM> of the area <NUM>, and the second check valve <NUM> is in the open position when the mushroom member <NUM> is moved away from the sealing surface <NUM> in the direction D. The second check valve <NUM> is a normally closed valve, in which the biasing member <NUM> exerts a force on the mushroom member <NUM> in the direction Z that causes the second check valve to maintain the closed position. When the second check valve <NUM> is in the closed position, fluid in the area <NUM> is prevented from moving past second check valve <NUM> and outlet nozzle <NUM>. Movement of the mushroom member <NUM> in the direction D moves the second check valve <NUM> to the open position and allows fluid from the area <NUM> to move past second check valve <NUM> and through the outlet nozzle <NUM>. In certain embodiments, the second check valve <NUM> is a high flow valve that is configured to prevent static drip of fluid from the outlet nozzle <NUM> when the second check valve <NUM> is in the closed position. In some embodiments, the second check valve <NUM> is a slow acting check valve that, for example, has a cracking pressure of <NUM> mbar (<NUM> psi) or greater, such as <NUM> mbar (<NUM> psi) or greater, such as <NUM> mbar (<NUM> psi) or greater, such as <NUM> mbar (<NUM> psi) or greater. In some embodiments, upon activation of the pump <NUM>, the second check valve <NUM> will remain in the open position for between about <NUM> seconds and about <NUM> seconds (the operating time to dispense a selected dose of fluid), such as about <NUM> seconds even though first check valve <NUM> opens and closes multiple times in that same time period. In the illustrated embodiment, the second check valve <NUM> is a mushroom valve. In alternative embodiments, the second check valve <NUM> can be, for example, a ball and spring valve, a flapper valve, or the like.

In the invention, the second check valve <NUM> has a greater cracking pressure than the first check valve <NUM>. In various embodiments, the second check valve <NUM> has a cracking pressure between about <NUM> mbar (<NUM> psi) and about <NUM> mbar (<NUM> psi), and the first check valve <NUM> has a cracking pressure between about <NUM> mbar (<NUM> psi) and about <NUM> mbar (<NUM> psi). In certain embodiments, the ratio of cracking pressure for the second check valve <NUM> to the cracking pressure for the first check valve <NUM> is between about <NUM> to <NUM> and about <NUM> to <NUM>. In alternative embodiments, the ratio of cracking pressure for the second check valve <NUM> to the cracking pressure of the first check valve <NUM> can be greater than <NUM> to <NUM>.

To operate the dispenser <NUM>, a user activates the pump <NUM> using the actuator (not shown), which causes fluid to flow from the pump chamber <NUM>, through the outlet nozzle <NUM>, and into a hand of the user. Activation of the pump <NUM> causes the pump chamber <NUM> to move from an expanded position to a compressed position, which causes the fluid in the pump chamber <NUM> to travel through the pump outlet <NUM> past the first check valve <NUM> with a force sufficient to cause the first check valve <NUM> to move to an open position. That is, the force applied by the fluid creates a pressure on the first check valve <NUM> that exceeds the cracking pressure of the first check valve <NUM> which causes the first check valve <NUM> to move to the open position. Movement of the first check valve <NUM> to the open position allows the fluid to move past the first check valve <NUM> and into the area <NUM> between the first check valve <NUM> and the second check valve <NUM>. As fluid moves through the area <NUM>, the fluid engages the second check valve <NUM> with a force applied to the mushroom member <NUM> of the second check valve <NUM> sufficient to cause the mushroom member <NUM> to move to an open position in the direction D. That is, the force applied by the fluid (from activation of the pump) also creates a pressure on the second check valve <NUM> that exceeds the cracking pressure of the second check valve, which causes the second check valve to move to the open position. Movement of the second check valve <NUM> to the open position allows the fluid to flow past the second check valve <NUM>, through the outlet nozzle <NUM> of the dispenser <NUM>, and into the hand of a user. The contraction of pump chamber <NUM> also causes first check valve <NUM> to rapidly close in order to prevent fluid from being drawn in from area <NUM> and forcing fluid to be drawn in from container.

After air from upstream of the pump chamber <NUM> exits the pump chamber <NUM>, the pump <NUM> is primed (i.e., fluid is moved from the container and into the pump chamber <NUM>) such that another activation of the pump causes fluid to be pumped toward the outlet nozzle <NUM> of the dispenser <NUM>. In some embodiments, multiple pump chambers <NUM> are used. In some embodiments, one or more of the multiple pump chambers <NUM> pump air, and thus do not need to prime and the remaining pump chambers <NUM> pump liquid. In some embodiments, the one or more pump chambers <NUM> pump a mixture of liquid and air, and thus are primed when a selected percentage of the volume comprises liquid. As the pump chamber <NUM> is fully compressed, the force applied by the liquid on the first check valve <NUM> will decrease until the pressure applied on the first check valve is less than the cracking pressure of the first check valve, which may cause the first check valve <NUM> to return to the closed position. In some embodiments, first check valve <NUM> does not return to a closed position until a negative pressure develops in pump chamber <NUM>. As the fluid stops flowing out of the outlet nozzle <NUM>, the force applied by the liquid on the second check valve <NUM> will decrease until the pressure applied on the second check valve <NUM> is less than the cracking pressure of the second check valve, which will cause the second check valve <NUM> to return to the closed position.

As the pump chamber <NUM> moves from the compressed position to the expanded position, a negative pressure is created in the pump chamber <NUM>. The negative pressure in the pump chamber <NUM> causes liquid from the container to enter the pump chamber through the pump inlet <NUM> and causes the first check valve <NUM> to close. In some embodiments, the first check valve <NUM> is advantageous because it prevents air and/or liquid in the area <NUM> from entering the pump chamber <NUM> through the pump outlet <NUM>. If air and/or residual liquid enter the pump chamber <NUM> through the pump outlet <NUM> during operation of the pump <NUM>, and, in particular, during priming of the pump, the pump <NUM> may be less efficient and possibly not prime. In the dispenser according to the invention, the second check valve <NUM> is advantageous because it prevents residual fluid in the area <NUM> from dripping through the outlet nozzle <NUM> between activations of the pump <NUM>.

Claim 1:
A dispenser (<NUM>, <NUM>) comprising:
a housing (<NUM>);
an container (<NUM>) disposed in the housing (<NUM>) for holding a liquid;
the container (<NUM>) having a liquid outlet located proximate the bottom of the container (<NUM>);
an outlet nozzle (<NUM>); and
a pump (<NUM>, <NUM>) disposed between the container (<NUM>) and the outlet nozzle (<NUM>, <NUM>),
the pump (<NUM>, <NUM>) having:
a pump inlet (<NUM>) in fluid communication with the liquid outlet of the container (<NUM>);
a pump outlet (<NUM>, <NUM>) in fluid communication with the outlet nozzle (<NUM>, <NUM>);
a pump chamber (<NUM>, <NUM>) in fluid communication with the pump inlet (<NUM>) and the pump outlet (<NUM>, <NUM>), wherein the pump chamber (<NUM>, <NUM>) is movable between an expanded position and a compressed position;
a first check valve (<NUM>, <NUM>) disposed between the pump (<NUM>, <NUM>) and the outlet nozzle,
wherein the first check valve (<NUM>, <NUM>) has a first cracking pressure; and
a second check valve (<NUM>, <NUM>) disposed between the first check valve (<NUM>, <NUM>) and the outlet nozzle, wherein the second check valve (<NUM>, <NUM>) has a second cracking pressure;
wherein the second cracking pressure of the second check valve (<NUM>, <NUM>) is greater than the first cracking pressure of the first check valve (<NUM>, <NUM>),
wherein the dispenser (<NUM>, <NUM>) is an inverted dispenser in which the container (<NUM>) is inverted and the container (<NUM>) is positioned so that at least a portion of the fluid in the container is located above the pump chamber (<NUM>, <NUM>).