Patent Publication Number: US-2005139612-A1

Title: Foam dispenser

Description:
FIELD OF THE INVENTION  
      This invention relates to foam dispensers and in particular foam dispensers having a rotary drive mechanism.  
     BACKGROUND OF THE INVENTION  
      Liquid dispensers for dispensing soap and the like are well known. There are a wide variety of liquid dispensers for use in association with liquid soap. Some of these dispense the soap or other liquid in the form of a foam. There are a number of advantages that are realized by dispensing in the form of foam. Specifically foam is easier to spread than the corresponding liquid. As well there is much less splashing or run-off since the foam has a much higher surface tension than the liquid. In addition, the foam requires much less liquid to produce the same cleansing power as compared to the un-foamed liquid due to the much higher surface area of the foam. Accordingly the cost to wash a specific number of hands is reduced since the amount of soap used is reduced. Similarly there are environmental benefits from using the foam since the amount of product used is reduced.  
      There are typically two types of foamers, one which uses a jet of air and another which mixes the liquid with air and then drives the combination through a porous material. The former type of foamer has the disadvantage that the quality of foam varies depending on the dispensing force. The latter design, although it works very well under most circumstances, has a number of characteristics that in certain circumstances are undesirable. For example it is difficult to adjust the ratio of air to liquid. Two example of the latter type of foamers are shown in U.S. Pat. No. 5,445,288 issued Aug. 29, 1995 and U.S. Pat. No. 6,082,586 issued Jul. 4, 2000 both issued to Banks. These foamers use a lever or pushbutton to activate the device. Another example of the latter type of foamer is shown in U.S. Pat. No. 5,037,006 issued Aug. 6, 1991 to Kock. This foamer is a squeeze operated foamer. All of these examples of foamers suffer from the limitation described above wherein ratio of air to liquid cannot be easily adjusted.  
      Accordingly it would be advantageous to provide a foam dispenser that has a consistent yet adjustable amount of discharge per shot. Further it would be advantageous to provide a foam dispenser wherein the ratio of the air to the liquid can be easily adjusted. Still further it would be advantageous to provide a foam dispenser that has a method of actuation that can easily be adapted to be used with a lever, a push button or an electrical motor.  
     SUMMARY OF THE INVENTION  
      The present invention is a foam dispenser for use with a container containing soap or other liquid. The device includes a rotary soap pump, a rotary air pump, a mixing chamber, an aeration gauze and an actuator or driver. The rotary soap pump has a soap inlet and a soap outlet and the soap inlet is operably connectable to the container. The rotary air pump has an air inlet and an air outlet. The mixing chamber is in flow communication with the air outlet and the soap outlet and the mixing chamber has an outlet. The aeration gauze is positioned such that an air and soap mixture that passes through the mixing chamber outlet passes through the gauze thereby producing foam. The actuator or driver is operably connected to the rotary soap pump and the rotary air pump.  
      In another aspect of the invention the invention is a foam dispenser for producing and dispensing foam. The dispenser includes a container, a rotary soap pump, a rotary air pump, a mixing chamber, a porous membrane an actuator or driver and a housing. The container is for containing a liquid. The rotary soap pump has a soap inlet and a soap outlet and the soap inlet is operably connectable to the container. The rotary air pump has an air inlet and an air outlet. The mixing chamber is in flow communication with the air outlet and the soap outlet. The mixing chamber has an outlet. The porous membrane is positioned such that an air and soap mixture that passes through the mixing chamber outlet passes through the porous membrane thereby producing foam. The actuator or driver is operably connected to the rotary soap pump and the rotary air pump. The housing has an interior and the container, the soap pump, the air pump, the mixing chamber are housed within the housing interior.  
      Further features of the invention will be described or will become apparent in the course of the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention will now be described by way of example only, with reference to the accompanying drawings, in which:  
       FIG. 1  is a perspective view of a liquid dispenser constructed in accordance with the present invention;  
       FIG. 2  is a cross sectional view of a liquid dispenser of the present invention;  
       FIG. 3  is a cross sectional view of one embodiment of the rotary foam pump assembly of the present invention wherein the assembly includes a double lobe pump;  
       FIG. 4  is a cross sectional view of an alternate embodiment of the rotary foam pump assembly of the present invention wherein the assembly includes a double vane pump;  
       FIG. 5  is a cross sectional view of a third embodiment of the rotary foam pump assembly of the present invention wherein the assembly includes a double gear pump;  
       FIG. 6  is a cross sectional view of a fourth embodiment of the rotary foam pump assembly of the present invention wherein the assembly includes a double peristaltic pump. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIG. 1  and  FIG. 2 , a liquid dispenser containing a liquid container and pump is shown generally at  10 . Dispenser  10  includes a housing  12  and a drive bar or lever  14 . The lever  14  is operably connected to the rotary pump assembly  16  which is connected to a collapsible liquid container  18 . The lever  14  is attached to a drive rack  34  which engages the pumps in the rotary pump assembly.  
      Referring to  FIG. 3 , the first embodiment of the rotary pump assembly is a double lobe pump and is shown generally at  20 . Double lobe pump  20  includes a soap pump  22  and an air pump  24 . The soap pump  22  and the air pump  24  each have a pair of intermeshing tri-lobes  26  and  28 , respectively. Each pair of tri-lobes  26 ,  28  rotate in opposite directions. Each of the soap pump  22  and the air pump  24  have a soap pump housing  30  and an air pump housing  32 , respectively. A drive rack  34  is connected to the drive bar or lever  14 . The drive rack  34  is operably connected to the lobes  26  and  28 . The drive rack  34  is biased in the rest position. The soap pump  22  has a soap inlet  38  and a soap outlet  40 . A one way soap valve  42  is positioned in the soap outlet  40 . The soap inlet  38  is in flow communication with the liquid inside the collapsible container  18 . The air pump  24  has an air inlet  44  and an air outlet  46  with a one way air valve  48  positioned therein. The soap outlet  40  and the air outlet  46  are in flow connection with a mixing channel or chamber  50 . The soap/air mixture passes through a porous membrane or aeration gauze  52  to produce foam  54 .  
      In use, a user pushes the lever  14  which drives the drive rack  34  and causes the soap lobes  26  and the air lobes  28  to advance, thus moving soap from the soap inlet  38  to the soap outlet  40  and air from the air inlet  44  to the air outlet  46 . The soap and the air mix in the mixing chamber  50  and the soap/air mixture is forced through the gauze  52  to produce foam  54 .  
      The above describes the basic concept of the rotary foam dispenser of the present invention. However it will be appreciated by those skilled in the art that there are a number of different rotary pumps that could also be used. For example a vane pump ( FIG. 4 ), a gear pump ( FIG. 5 ) or a peristaltic pump ( FIG. 6 ). Each of which is described in more detail below. Only the features that are different from those described above will be discussed.  
      Referring to  FIG. 4 , a double vane pump is shown generally at  60 . Double vane pump  60  includes a soap vane pump  62  and an air vane pump  64 . Each of the soap pump  62  and the air pump  64  have a soap pump housing  66  and an air pump housing  68 , respectively. Each vane pump has a plurality of vanes  70  extending outwardly from a rotatable drive wheel  72 . The vanes  70  are evenly spaced around the rotatable drive wheel  72 . A drive rack  34  is connected to the drive bar or lever  14 . The drive rack  34  is operably connected to the rotatable drive wheels  72 . The drive rack  34  is biased in the rest position. The soap pump  62  has a soap inlet  38  and a soap outlet  40 . A one way soap valve  42  is positioned in the soap outlet  40 . The soap inlet is in flow communication with the liquid inside the collapsible container  18 . The air pump  64  has an air inlet  44  and an air outlet  46  with a one way air valve  48  positioned therein. The soap outlet  40  and the air outlet  46  are in flow connection with a mixing channel or chamber  50 . The mixture passes through a porous membrane  52  to produce foam  54 .  
      Referring to  FIG. 5 , a double gear pump is shown generally at  80 . Double gear pump  80  includes a soap gear pump  82  and an air gear pump  84 . Each of the soap pump  82  and the air pump  84  have a soap pump housing  86  and an air pump housing  88  respectively. The soap pump  82  and the air pump  84  each have a drive gear  90  and  92  and a pump gear  94  and  96  respectively and the drive gear is rotatable in the pump gear. A drive rack  34  is connected to the drive bar or lever  14 . The drive rack  34  is operably connected to the drive gears  90  and  92 . The drive rack  34  is biased in the rest position. The soap pump  82  has a soap inlet  38  and a soap outlet  40 . A one way soap valve  42  is positioned in the soap outlet  40 . The soap inlet  38  is in flow communication with the liquid inside the collapsible container  18 . The air gear pump  84  has an air inlet  44  and an air outlet  46  with a one way air valve  48  positioned therein. The soap outlet  40  and the air outlet  46  are in flow connection with a mixing channel or chamber  50 . The mixture passes through a porous membrane  52  to produce foam  54 .  
      Referring to  FIG. 6 , a double peristaltic pump is shown generally at  100 . Double peristaltic pump  100  includes a soap peristaltic pump  102  and an air peristaltic pump  104 . Each of the soap pump  102  and the air pump  104  have a soap pump housing  106  and an air pump housing  108 . The soap pump  102  has a flexible soap tube  110  around the inside periphery and a peristaltic drive wheel  112  with a plurality of paddles  114  are attached thereto. The paddles  114  engage the flexible soap tube  110  and move soap therethrough. Similarly the air pump  104  has a flexible air tube  116  and a peristaltic air drive wheel  118  with a plurality of paddles  120  attached thereto. A drive rack  34  is connected to the drive bar or lever  14 . The drive rack  34  is operably connected to the soap drive wheel  112  and air drive wheel  118 . The drive rack  34  is biased in the rest position. The soap pump  102  has a soap inlet  38  and a soap outlet  40  both in flow communication with the soap tube  110 . The soap inlet  38  is in flow communication with the inside of the collapsible container  18 . The air peristaltic pump  104  has an air inlet  44  and an air outlet  46 , each in flow communication with the air tube  116 . The soap outlet  40  and the air outlet  46  are in flow connection with a mixing channel or chamber  50 . The mixture passes through a porous membrane  52  to produce foam  54 .  
      It will be appreciated by those skilled in the art that the amount of air and soap can be easily adjusted by adjusting the stroke of the drive rack  34 . Further the ratio between the air and the soap can be easily adjusted by adjusting the gear ratio between the lever and the soap drive wheel relative to the lever and the air drive wheel.  
      The dispenser shown herein could be further enhanced by including a motion detector to determine when an object is within a predetermined range and to activate the device. Further, it will be appreciated by those skilled in the art that although the dispenser is shown with a lever  14  as an actuation device there are a number of other methods of actuation that would also work. Specifically, by way of example, dispensing could also be actuated with a push button or a crank.  
      As used herein, the terms “comprises” and “comprising” are to be construed as being inclusive and opened rather than exclusive. Specifically, when used in this specification including the claims, the terms “comprises” and “comprising” and variations thereof mean that the specified features, steps or components are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.  
      It will be appreciated that the above description related to the invention by way of example only. Many variations on the invention will be obvious to those skilled in the art and such obvious variations are within the scope of the invention as described herein whether or not expressly described.