FOAM DISPENSERS HAVING HIGH AIR TO LIQUID RATIOS AND FOAM DISPENSERS THAT DISPENSE ACCURATE VOLUME DOSES OF FOAM

TECHNICAL FIELD

[0001]The present invention relates generally to foam dispenser systems, and more particularly to foam dispensers that dispense foams created with a high air to liquid ratio, and also to foam dispensers that dispense very accurate and repeatable micro-volume doses of foam product.

BACKGROUND OF THE INVENTION

[0002]Low pressure liquid dispenser systems, such as, for example, liquid soap dispensers, provide a user with a predetermined amount of liquid soap or sanitizer upon actuation of the dispenser. These low-pressure dispensing systems have an output pressure of less than 15 pounds per square inch (“PSI”). 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. Typically, the air to liquid ratio of foam soap dispensers and sanitizer dispensers is between about 1 to 2 to about 1 to 7. U.S. Pat. No. 10,08467 discloses foam soap product made with air to liquid ratios of up to 20 to 1 using a single air/liquid mixing chamber and up to 50 to 1 using two sequential mixing chambers, wherein air is injected into liquid in the first mixing chamber to form a liquid air mixture and additional air is injected in the liquid air mixture in the second mixing chamber to produce the foam. These low air to liquid ratios may not be applicable to all foaming products, such as liquid concentrates, which may need air to liquid ratios of greater than 50 to 1, such as for example, 75 to 1 or greater. Accordingly, there is a need for a soap or sanitizer dispenser that has the ability to provide a foam product made with a high air to liquid ratio.

[0003]In addition, current foam dispensers provide, for example, between 1 and 3 milliliters of soap or sanitizer in each dispense. The dose size often varies significantly between dispenses. This variance may be as high as a 10% variance. In addition, these dose sizes are too large for complying with efficacy standards that test products on finger pads and thumb pads. In efficacy studies that utilize a new ASTM testing method (ASTM e1838-17), which is incorporated by reference herein in its entirety), a 0.020 ml volume of the test product is added to a finger pad or thumb pad. To comply with the standard, it is critical that the volume of liquid in the test product is dispensed at precisely the required volume. This is easy to do for liquid test products. However, if the test product will be dispensed as a foam, such as, for example, a foam soap, and a user wants to test the product in its foam form, there is no reliable and repeatable way to obtain a precise volume of foam that contains 0.020 ml of liquid. Current foam dispensers cannot repeatedly provide constant accurate micro-volumes of liquid in the form of a foam, which are required to be applied to a test subject's finger and thumb pads. Accordingly, there is a need for a soap or sanitizer dispenser that has the ability to provide a micro-volume dose of foam having high air to liquid ratio.

SUMMARY

[0004]Exemplary embodiments of micro-dose foam generators and foam dispensers are disclosed herein. An exemplary foam generator includes a housing that has a charging chamber. The charging chamber includes an inlet, an upper portion and a lower portion. The lower portion has a tapered section. The tapered section has an upper side and a lower side. The charging chamber includes an outlet that has a smaller diameter than the inlet. A porous foam media is also included. At least a portion of the porous foam media is located within the tapered section. The porous foam media has a first foam density at the top of the tapered section and a second foam density as the porous media extends downward in the tapered section. The second foam density is denser than the first foam density.

[0005]Exemplary foam dispensers for mixing a precise volume of liquid with a volume of air that is greater than 75 times the volume of liquid and providing a foam output are disclosed herein. An exemplary foam dispenser includes a housing, a liquid charging chamber and a compression chamber. A porous foam media is located at least partially in the compression chamber. There is a flow path through the compression chamber. The porous foam media has a foam density that increases in density along the fluid flow path. The liquid charging chamber is configured to hold a dose of foamable liquid. An air pump is included. The air pump is configured to deliver at least about 75 times the volume of foamable liquid. During operation a dose of foamable liquid is placed in the charging chamber and the air pump pumps a volume of air into the charging chamber, wherein the volume of air is at least about 75 times the volume of foamable liquid. The dispenser includes an outlet for dispensing a foam that is formed by mixing the volume of foamable liquid with the volume of air.

[0006]Another exemplary foam dispenser includes a housing, a first liquid pump, an air pump and a mixing chamber. The mixing chamber has a liquid inlet, an air inlet, and an outlet. The dispenser includes a foam generator. The foam generator has a tapered portion and a porous foam media. A fluid flow path extends through the foam generator. At least a portion of the porous foam media is compressed within the tapered portion. The density of the porous foam media increases along at least a portion of the flow path through the foam generator. The dispenser further includes a foam outlet.

[0007]Exemplary methodologies for producing a micro-volume dose of foam for testing formulations are also disclosed herein. An exemplary methodology for producing a micro-volume dose of foam includes providing an air pump that is configured to pump a volume of air for each dispense, providing a liquid pump that is configured to pump a volume of liquid and providing a foam generator. The foam generator has a charging chamber, a porous foam media and a tapered lower portion. At least a portion of the porous foam media is compressed in the tapered lower portion. A fluid flow path extends through the foam generator. The density of the porous foam media increases along at least a portion of the fluid flow path. The methodology includes placing a precise volume of liquid in the foam generator, wherein the precise volume of liquid is within +/−1% of a selected volume. The methodology includes pumping a volume of air through the foam generator, wherein the volume of air is at least 75 times the precise volume of liquid and dispensing the foam out of the foam dispenser.

[0008]An exemplary foam generator for a dispenser includes a housing that has a charging chamber. The charging chamber has an inlet and an outlet. The outlet has a smaller diameter than the inlet. A porous foam media is located in the housing. A fluid flow path extends between the inlet and the outlet. The porous foam media has an increasing density gradient along at least a portion of the fluid flow path.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a cross-sectional view of an exemplary embodiment of a dispenser for dispensing a foam having a precise micro-dose of liquid;

[0010]FIG. 2 is another cross-sectional view of the exemplary embodiment of a dispenser for dispensing a foam having a precise micro-dose of liquid of FIG. 1;

[0011]FIG. 3 is an exploded cross-sectional view of an exemplary embodiment of a foam generator;

[0012]FIG. 4 is a cross-sectional view of the foam generator of FIG. 3;

[0013]FIG. 5 is an exemplary embodiment of a foam dispenser that dispenses a foam having an air to liquid ratio that is greater than 75 to 1; and

[0014]FIG. 6 is an exemplary embodiment of a foam dispenser that dispenses a foam formed from a concentrate, a diluent and air, with the foam having an air to liquid ratio that is greater than 75 to 1.

DETAILED DESCRIPTION

[0015]The present application discloses exemplary embodiments of foam dispensers that produce foam with a high air to liquid ratio. High air to liquid ratio foam should be construed to mean a foam product that is produced by using an air pump that is configured to pump a selected volume of air that is mixed with a selected volume of liquid and forced through a foam generator, wherein the volume of air is at least 75 times the volume of liquid. A micro-dose of fluid should be construed to be less than 0.05 ml. In some embodiments, micro-dose of fluid may be about 0.020 ml. In some embodiments, the micro-dose of fluid may be less than 0.2 ml. In some embodiments, the micro-dose of fluid may be less than 0.1 ml.

[0016]Referring to FIGS. 1 and 2, which are cross-sectional views of an exemplary embodiment of a dispenser 100 for producing and dispensing a foam having a precise micro-dose of liquid. Dispenser 100 includes a supporting frame 100 that includes a base 102. Supporting frame 101 includes a support member 202 for supporting a foam generator 150. In addition, dispenser 100 includes an actuator 103. Actuator 103 moves up and down with respect to frame 101. In this exemplary embodiment, actuator 103 is biased upward by a pair of springs 210. Actuator 103 includes a pump retention member 212. Pump retention member 212 retains air pump 104.

[0017]In this exemplary embodiment, air pump 104 is a piston pump and includes a piston 108. As piston 108 moves upward, air is compressed in air pump chamber 106 and is expelled out of outlet nozzle 110. In this exemplary embodiment, a sealing member 112 is secured to the bottom of piston 108. Sealing member 112 seals against flared flange 160 of the foam generator 150 when the actuator 103 moves downward.

[0018]In this exemplary embodiment, air pump 104 has one or more air pump chambers 106. The volume of the one or more air pump chambers 106 is selected so that the volume of air in the one or more air pump chambers 106 is at least about 75 times the volume of liquid that is to be foamed.

[0019]An exemplary air pump that may be used in accordance with embodiments of the present invention is shown and described in PCT patent application number WO 2005/105320, which is titled Dispensing Device, and which is incorporated in its entirety by reference. This exemplary pump may be used by removing the dip tube and modifying the outer portion of the piston. Such modifications of the outer portion may include adding a sealing member. In this exemplary embodiment, the air pump would have two air pump chambers as the pump chamber identified as pumping liquid in WO 2005/105320 would pump air and the air pump chamber would also pump air.

[0020]Another exemplary an air pump is shown and described in U.S. Pat. No. 9,341,176, which is titled Diaphragm Pump, and which is incorporated herein by reference in its entirety. The diaphragm pump can be configured to operate for a selected number of revolutions or fractions thereof. Accordingly, the diaphragm pump may be configured to provide virtually any desired volume of air.

[0021]The air pumps are preferably configured to supply a volume of air that is at least about 75 times the volume of the liquid. In some embodiments, the volume of air is at least about 100 times the volume of the liquid. In some embodiments, the volume of air is at least about 150 times the volume of the liquid. In some embodiments, the volume of air is at least about 200 times the volume of the liquid. In some embodiments, the volume of air is at least about 250 times the volume of the liquid. In some embodiments, the volume of air is at least about 300 times the volume of the liquid. In some embodiments, the volume of air is at least about 350 times the volume of the liquid. In some embodiments, the volume of air is at least about 400 times the volume of the liquid. In some embodiments, the volume of air is at least about 450 times the volume of the liquid. In some embodiments, the volume of air is at least about 500 times the volume of the liquid. In some embodiments, the volume of air is at least about 550 times the volume of the liquid. In some embodiments, the volume of air is at least about 600 times the volume of the liquid. In some embodiments, the volume of air is at least about 650 times the volume of the liquid. In some embodiments, the volume of air is at least about 700 times the volume of the liquid. In some embodiments, the volume of air is between about 75 and 1000 times the volume of the liquid. In some embodiments, the volume of air is between about 100 and 1000 times the volume of the liquid. In some embodiments, the volume of air is between about 200 and 800 times the volume of the liquid. In some embodiments, the volume of air is between about 300 and 700 times the volume of the liquid. In some embodiments, the volume of air is between about 400 and 600 times the volume of the liquid.

[0022]Foam generator 150 includes a housing 152. In this exemplary embodiment, housing 152 is cylindrical. Housing 152 has a flared flange 160 for engaging sealing member 110 of piston 108 to provide a leak-free connection to the piston 108 sealing member 110 when the pump 104 is delivering the selected volume of air.

[0023]In this exemplary embodiment, housing 152 includes a charging chamber or mixing chamber 181. In this exemplary embodiment, charging chamber 181 is cylindrical. Other shapes, such as, for example, shapes have cross-sections in the form of an oval shape, a polygonal shape, a rectangular shape, a square shape, or the like, may be used.

[0024]In this exemplary embodiment, a foamable liquid is added to the charging chamber 181 using a pipette so that a very accurate micro dose of liquid may be foamed. In some embodiments, a liquid pump (not shown) and liquid conduit (not shown) are configured to supply liquid to the charging chamber 181.

[0025]Housing 152 includes a tapered portion 156. In this exemplary embodiment, tapered portion 156 has a conical shape. The tapered portion 156 may have other shapes that have different cross-sectional shapes, such as, for example, a triangular cross-section, a rectangular cross-section, or the like.

[0026]Located at least partially within the tapered portion 156 of housing 152 is a porous foam media 170. Porous foam media 170 is preferably a sponge. The density of porous foam media 170 increases in the direction of fluid flow. Accordingly, the density of the porous foam media 170 at the top of the porous foam media 170 is less than the density of the porous foam media 170 at the half-way point. And the density of the porous foam media 170 at the half-way point is less than the density at the end of the porous foam media 170.

[0027]In some exemplary embodiments, porous foam media 170 is a sponge that is between 100% and 400% more dense than sponges used in a standard dispenser. The density of a standard density sponge used in a foam soap or sanitizer dispenser is 70 pores per inch. Accordingly, the porosity of the porous foam media 170 (in its uncompressed state) may preferably be between about 70 pores per inch and about 280 pores per inch.

[0028]In some embodiments, porous foam media 170 has a compressed state and uncompressed state. In some embodiments, in the uncompressed state, porous foam media 170 has a cylindrical shape. In some embodiments, in the uncompressed state, porous foam media 170 has a density that is substantially the same along a flow path from top to bottom and in a compressed state has a density that increases along at least a portion of the flow path from the top to the bottom. This may be achieved by, for example, compressing the sponge in a funnel shaped or tapered chamber.

[0029]In some embodiments, porous foam media 170 has an increasing density gradient. In some embodiment, porous foam media 170 has a variable density gradient.

[0030]In some embodiments, the porous foam media 170 being urged into and compressed by the tapered portion 156 causes the porous foam media to have an increasing density gradient.

[0031]In some embodiments, a tapered portion 156 is not required provided that the porous foam media 170 has an increasing density gradient for at least a portion of the fluid flow path through the porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 70 percent of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 60 percent of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 50 percent of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 40 percent of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 30 percent of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 3 millimeters of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 4 millimeters of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 5 millimeters of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 6 millimeters of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 7 millimeters of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 8 millimeters of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 9 millimeters of the length of the flow path through porous foam media 170. In some embodiments, the porous foam media 170 has an increasing foam density along at least 10 millimeters of the length of the flow path through porous foam media 170.

[0032]Foam generator 150 includes an optional screen 166. In some embodiments, there is no space between the optional screen 166 and the porous foam media 170. In some embodiments, the optional screen 166 holds the porous foam media 170 in a compressed state.

[0033]In addition, foam generator 150 includes a retaining member 164. In this exemplary embodiment retaining member 164 has a cylindrical shape and is retained within housing 152 by a friction fit. Other types of connections may be used, such as, for example, a screw connection, a welded connection, a threaded connection, an adhesive connection, or the like.

[0034]Housing 152 also includes an outlet passage 157. In this exemplary embodiment, outlet passage 157 is cylindrical. Outlet passage 157 may have other shapes, such as, for example, a slot shape.

[0035]Outlet passage 157 is configured to apply a selected back pressure to the fluid flowing through the outlet passage 157. The back pressure is generated in the fluid flow path between the air pump and the outlet. The back pressure generated by outlet passage 157 is greater than the back pressure generated by a standard dispenser outlet. The back pressure generated by a standard dispenser outlet has been observed as an average peak back pressure of 0.16 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 0.5 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 0.6 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 0.7 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 0.8 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 0.9 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 1.0 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 1.1 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 1.2 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 1.3 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 1.4 psi. In some embodiments, the back pressure generated by outlet passage 157 is greater than 1.5 psi.

[0036]To increase the back pressure, preferably outlet passage 157 is narrower than a standard dispenser outlet. A standard dispenser outlet typically has a diameter of 0.15 inches. In some embodiments, outlet passage 157 is about ½ to ¼ of the diameter of a standard outlet nozzle. Accordingly, preferably, outlet passage 157 is between about 0.075 inches to 0.0375 inches.

[0037]In some embodiments, outlet passage 157 has a length and a width (or diameter depending on its shape or configuration). In some embodiments, the length of outlet passage 157 is greater than about 5 times the width or diameter. In some embodiments, the length of outlet passage 157 is greater than about 6 times the width or diameter. In some embodiments, the length of outlet passage 157 is greater than about 7 times the width or diameter. In some embodiments, the length of outlet passage 157 is greater than about 8 times the width or diameter. In some embodiments, the length of outlet passage 157 is greater than about 9 times the width or diameter. In some embodiments, the length of outlet passage 157 is greater than about 10 times the width or diameter.

[0038]Preferably the entire volume of the air pump 104 is pumped through the foam generator in about 0.7 seconds or less. In some embodiments, the entire volume of the air pump 104 is pumped through the foam generator in about 0.6 seconds or less. In some embodiments, the entire volume of the air pump 104 is pumped through the foam generator in about 0.5 seconds or less. In some embodiments, the entire volume of the air pump 104 is pumped through the foam generator in about 0.5 seconds or less. In some embodiments, actuator 103 is an electrically driven actuator. In some embodiments, use of an electrically driven actuator may be preferred so that the volume of air is pushed through the foam generator 150 in substantially the same amount of time for each dose of foam delivered.

[0039]One method of operation for foam dispenser 100 may include using placing 0.20 ml of foamable liquid in charge chamber 181. The liquid may be placed by, for example, using a pipette (not shown) or a micro-dose pump (not shown). Actuator 103 is moved downward. Actuator 103 may be moved downward manually or with a motor (not shown) including any necessary gearing (not shown). As sealing member 112 engages flared flange 152, an air-tight seal is created. Further downward movement of actuator 103 compresses the one or more air pump chamber 160. As the one or more air pump chambers 160 are compressed, air is forced out of air outlet 110 and mixes with the foamable liquid in charge chamber 181 and the fluid mixture is forced through optional screen 166, through the porous foam media 160, which may be a sponge, and through the outlet passage 157, where the foam is dispensed out of outlet 158. As described above, the sponge preferably has an increasing foam density in the direction of flow.

[0040]In some embodiments, this method is “pre-run” several times to “wet” the porous foam media 170. After the foam dispenser 100 has been used enough so that porous foam media 170 has been pre-wetted, the foam dispenser 100 provides a high air to liquid ratio foam that is made of a precise dose of fluid.

[0041]FIG. 3 is an exploded cross-sectional view of an exemplary embodiment of a foam generator 350. Foam generator 350 includes a housing 352. In this exemplary embodiment, housing 352 is cylindrical.

[0042]Housing 152 includes a tapered portion 356. In this exemplary embodiment, tapered portion 356 has a conical shape. The tapered portion 356 may have other shapes, such as, for example, a triangular cross-section, or the like. Housing 352 includes an outlet passage 357. In this exemplary embodiment, outlet passage 357 is cylindrical. Outlet passage 357 may have other shapes, such as, for example, a slot shape.

[0043]Outlet passage 357 is configured to apply a selected back pressure to the fluid flowing through the outlet passage 357. As discussed above, the selected back pressure may be greater than 0.5 psi, greater than 0.6 psi, greater than 0.7 psi, greater than 0.8 psi, greater than 0.9 psi, greater than 1.0 psi, greater than 1.1 psi, greater than 1.2 psi, greater than 1.3 psi, greater than 1.4 psi, and/or greater than 1.5 psi. The back pressure generated by outlet passage 357 is greater than the back pressure generated by a standard dispenser outlet. Preferably outlet passage 357 is narrower than a standard dispenser outlet. A standard dispenser outlet typically has a diameter of 0.15 inches. In some embodiments, outlet passage 357 is about ½ to ¼ of the diameter of a standard outlet nozzle. Accordingly, preferably, outlet passage 357 is between about 0.075 inches to 0.0375 inches.

[0044]In some embodiments, outlet passage 357 has a length L and a width or diameter D. In some embodiments, the length L of outlet passage 357 is greater than about 5 times the width or diameter D. In some embodiments, the length L of outlet passage 357 is greater than about 6 times the width or diameter D. In some embodiments, the length L of outlet passage 357 is greater than about 7 times the width or diameter D. In some embodiments, the length L of outlet passage 357 is greater than about 8 times the width or diameter D. In some embodiments, the length L of outlet passage 357 is greater than about 9 times the width or diameter D. In some embodiments, the length L of outlet passage 357 is greater than about 10 times the width or diameter D.

[0045]Located at least partially within the tapered portion 356 of housing 352 is a porous foam media 370. Porous foam media 370 is preferably a sponge. The density of porous foam media 370 increases in the direction of fluid flow. Accordingly, the density of the porous foam media 370 at the top of the porous foam media 370 is less than the density of the porous foam media 370 at the half-way point. And the density of the porous foam media 370 at the half-way point is less than the density at the end of the porous foam media 370. As described above, the tapered portion 356 may not be needed provided that the porous foam media 370 has an increasing density gradient along at least a portion of the fluid flow path.

[0046]In some exemplary embodiments, porous foam media 370 is a sponge that is between 100% and 400% more dense than sponges used in a standard dispenser. The density of a standard density sponge is 70 pores per inch. Accordingly, preferably, the porosity of the porous foam media 170 (in its uncompressed state) is between about 70 pores per inch and about 280 pores per inch.

[0047]In some embodiments, porous foam media 370 has a compressed state and uncompressed state. In some embodiments, in the uncompressed state, porous foam media 370 has a cylindrical shape. In some embodiments, in the uncompressed state, porous foam media 370 has a density that is substantially the same along a flow path from top to bottom and in a compressed state has a density that increases along at least a portion of the flow path from the top to the bottom.

[0048]In this exemplary embodiment, porous foam media 370 has a cylindrical shape in an uncompressed state as shown in FIG. 3 and a conical shape in its compressed state as shown in FIG. 4. The porous foam media 370 may include any of the physical characteristics and/or attributes identified above with respect to porous foam media 170, a few of which are redescribed below.

[0049]In some embodiments, a tapered section 356 may not be needed provided porous foam media 370 has an increasing density gradient. In some embodiments, porous foam media 370 has a variable density gradient.

[0050]Foam generator 350 includes an optional screen 366. In some embodiments, there is no space between the optional screen 366 and the porous foam media 370. In some embodiments, the optional screen 366 holds the porous foam media 370 in a compressed state. In addition, foam generator 350 includes a retaining member 364. In this exemplary embodiment retaining member 164 has a cylindrical shape and is retained within housing 352 by a friction fit. Other types of connections may be used, such as, for example, a screw connection, a welded connection, a threaded connection, an adhesive connection, or the like.

[0051]FIG. 4 is a cross-sectional view of the foam generator 350 in its assembled state.

[0052]The exemplary foam generator 350 may be used in a configuration, such as that described above for a micro-dose foam dispenser. In the micro-dose foam dispensers, a dose of liquid is placed in the charge chamber 380 or mixing chamber 380. After the liquid is placed in the charge chamber 380, air is forced through the charge chamber 380 where the air mixes with the liquid and is passed through the increasing density gradient of the porous foam media 370.

[0053]The exemplary foam generator 350 may also be used in commercial foam dispenser that is used for dispensing soap or sanitizer in a user's hand for the purpose of washing or sanitizing the persons hands. FIGS. 5 and 6 illustrate some exemplary foam dispensers 400, 500.

[0054]FIG. 5 is an exemplary embodiment of a foam dispenser 500 that dispenses a foam having an air to liquid ratio that is greater than 75 to 1. Foam dispenser 500 includes a housing 502. Foam dispenser 500 includes a liquid container 520. Liquid container 520 may be a permanent reservoir that is refillable. In some embodiments, container 520 is part of a refill unit, that may be removed when empty and replaced with a full refill unit. Foam dispenser 500 includes a pump 525. A liquid conduit 524 extends from container 520 to pump 525. Foam dispenser 500 includes a one-way liquid inlet valve 528 proximate a foam generator 350. A liquid inlet conduit 527 extends from pump 525 to an optional one-way liquid inlet valve 528. Foam dispenser 500 includes an air pump 530. An air inlet conduit 531 places air pump 530 in fluid communication with foam generator 350. Preferably liquid pump 525 and air pump 530 are separate pumps. However, in some embodiments, liquid pump 525 and air pump 530 are part of a single pump, such as, for example, the sequentially activated multi-diaphragm foam pumps shown and described in U.S. Pat. No. 10,080,467, U.S. Patent No. U.S. Pat. No. 10,065,199, U.S. Patent No. U.S. Pat. No. 10,143,339, which are incorporated herein in their entirety by reference. When using a sequentially activated multi-diaphragm foam pump, the liquid pump chamber may have a very small volume, while a plurality of air pump chambers have very large volumes in comparison with the volume of the liquid pump chamber. In addition, the speed of the rotation of the pump may be high enough that “slippage” occurs. Slippage results in significantly more air being pumped per rotation of the pump than liquid as the air pump chambers pump full chambers of air, while the liquid pump chamber pumps less than full chambers of liquid. Optionally, a flow control valve (not shown) may be used to choke or slow the flow of liquid to create the desired ratio of air to liquid.

[0055]Foam dispenser 500 is preferably a touch-free foam dispenser and includes all of the standard components for controlling the operation of the dispenser, such as, for example, a power source (not shown), an object sensor (not shown), a processor (not shown), memory (not shown), one or more indicators (not shown), one or more motor controllers (not shown), and any other required components. In some embodiments, foam dispenser 500 is a manual dispenser.

[0056]The foam dispenser 500 may operate in a number of ways. In some embodiments, air and liquid are sequentially pumped into foam generator 350. In some embodiments, liquid is pumped into the charge chamber (not shown) and then air is pumped through the charge chamber. In some embodiments, air and liquid are pumped simultaneously into the charge chamber. In some embodiments, a shot of liquid is pumped into the charge chamber and the shot of liquid is followed by two or more shots of air, or a steady stream of air. This process may be repeated until a full dose of foam is produced.

[0057]FIG. 6 is an exemplary embodiment of a foam dispenser 600 that dispenses a foam formed from a concentrate, a diluent and air, with the foam having an air to liquid ratio that is greater than 75 to 1. Foam dispenser 600 is similar to foam dispenser 500 and like parts are not redescribed with respect to FIG. 6. Foam dispenser 600 also includes a second container 620. Second container 620 is a concentrate container. In this exemplary embodiment, container 520 is filled with a diluent, such as, for example, water. Container 620 may be a permanent reservoir. Container 620 may be a refill unit that is removed when empty and replaced with a full container. Dispenser 625 includes a second liquid pump 625, which is placed in fluid communication with container 620 through conduit 624. The outlet of pump 625 is placed in fluid communication with foam generator 350 through conduit 627 and one-way liquid inlet valve 628.

[0058]Similar to foam dispenser 500, pumps 525, 530 and 625 pumps may be separate pumps. In some embodiments, two or more of the pumps are included in a single pump housing.

[0059]The foam dispenser 600 may operate in a number of ways. In some embodiments, air, concentrate and diluent are sequentially pumped into foam generator 350. In some embodiments, liquid concentrate is pumped into the charge chamber (not shown), diluent is pumped into the charge chamber and then air is pumped through the charge chamber. In some embodiments, air, concentrate and water are pumped simultaneously into the charge chamber. In some embodiments, a shot of concentrate is pumped into the charge chamber and the shot of concentrate is followed by one or more shots of diluent, followed by one or more shots of air. This process may be repeated until a full dose of foam is produced. In some embodiments, the concentrate and the diluent are “premixed” prior to being pumped into the charge chamber. Other sequences may be used depending on the mix ratios desired. In some embodiments, all of the liquid is pumped into the charge chamber and then the air is pumped into the charge chamber to foam the fluid and dispense the foam.

[0060]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 applicants 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 applicants' general inventive concept.