Abstract:
A foaming assembly includes a porous foaming element, a liquid chamber and an air chamber. The porous foaming element has an air inlet, a liquid inlet and an outlet. The porous foaming element has at least two zones of different pore sizes. The liquid chamber is in flow communication with the porous foaming element. The liquid chamber has a volume that is movable between an at rest postion to an activation position. The air chamber is in flow communication with the porous foaming element. The air chamber has a volume that is movable between an at rest position to an activation position. Liquid and air are forced into the porous foaming element under pressure wherein they mix to form foam which exits through the outlet. A dispenser may include a foaming assembly and a liquid container.

Description:
FIELD OF THE DISCLOSURE 
     This disclosure relates to foam dispensers and in particular foam dispensers having a porous foaming element wherein the air and liquid mix within the porous foaming element. 
     BACKGROUND 
     Foam dispensers are well known and widely used commercially. A wide variety of foam dispensers have been developed. In particular, a number of non-aerosol foam dispensers that use unpressurised liquid containers have been developed. The advantage of foam dispensers over soap dispensers is that for each wash less soap is used. 
     One way to reduce the costs for manufacturing is to reduce the number of components. Accordingly an embodiment that reduces the number of parts would be advantageous. 
     As well, an embodiment wherein the quality of foam is improved would also be advantageous. 
     SUMMARY 
     A foaming assembly includes a porous foaming element, a liquid chamber and an air chamber. The porous foaming element has an air inlet, a liquid inlet and an outlet. The porous foaming element has at least two zones of different pore sizes. The liquid chamber is in flow communication with the porous foaming element. The liquid chamber has a volume that is movable between an at rest position to an activation position. The air chamber is in flow communication with the porous foaming element. The air chamber has a volume that is movable between an at rest position to an activation position. Liquid and air are forced into the porous foaming element under pressure wherein they mix to form foam which exits through the outlet. A dispenser may include a foaming assembly and a liquid container. 
     The porous foaming element may have a smaller pore size zone and a larger pore size zone. The smaller pore size zone may be downstream of the larger pore size zone. Alternatively the smaller pore size zone may be upstream of the larger pore size zone. The porous foaming element may be generally bow tie shape in cross section. 
     The foaming assembly may include a foam cone, a piston and a bottle seal and wherein the piston and bottle seal define the liquid chamber, the foam cone, bottle seal and piston define the air chamber and movement inwardly of the foam cone into the bottle seal decreases the volume of the liquid chamber and the air chamber thereby forcing under pressure air and liquid into the porous foaming element. 
     The porous foaming element may be positioned in the foam cone between the foam cone and the piston. The porous foaming element may be made of compressible material and a smaller pore size zone is where the compressible material is more compressed than in a larger pore size zone. The shape of the porous foaming element may be defined by the geometry of the piston and the foam cone. 
     The foaming assembly may include a piston dome, a liquid and air bore and a main pump body and the piston dome, liquid and air bore and main body define a liquid chamber, the piston dome and liquid and air bore define the air chamber and movement inwardly of the piston dome into the main body decreases the volume of the liquid chamber and the air chamber thereby forcing under pressure air and liquid into the porous foaming element. The main pump body may include an exit nozzle and the porous foaming element is positioned in the exit nozzle between the liquid chamber and a venturi ring. The shape of the porous foaming element may be defined by the geometry of the exit nozzle and the venturi ring. 
     The foaming assembly may include a pump head, a bottle cap, an air piston, a piston and a main body and the main body and piston define the liquid chamber and the pump head, bottle cap, air piston, piston and main body define the air chamber movement inwardly of the pump head into the main body decreases the volume of the liquid chamber and the air chamber thereby forcing, under pressure, air and liquid into the porous foaming element. The shape of the porous foaming element may be defined by the geometry of the air piston and the pump head. 
     A foam dispenser includes a liquid container and a porous foaming element. The foam dispenser may further include a housing having an actuator wherein activating the actuator causes the air chamber and the liquid chamber to move between the at rest position to the activation position. The housing may further include at least one sensor and the actuator is activated responsive to the sensor sensing the presence of a user. 
     In another aspect there is provided a method of making foam including the steps of forcing air and liquid under pressure into a porous foaming element having at least two zones of different pore sizes wherein they mix to form foam which exits through the outlet. 
     Further features will be described or will become apparent in the course of the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments 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 foam dispenser including a foaming assembly with a porous foaming element; 
         FIG. 2  is blown apart perspective view of the foaming assembly of the foam dispenser of  FIG. 1 ; 
         FIG. 3  is a sectional view of the foaming assembly of  FIG. 2 ; 
         FIG. 4  is a sectional view of an alternate embodiment of the foaming assembly of  FIG. 2 ; 
         FIG. 5  is a sectional view of a further alternate embodiment of the foaming assembly of  FIG. 2 ; 
         FIG. 6  is a blown apart perspective view of a prior art foaming assembly; 
         FIG. 7  is a blown apart perspective view of an alternate embodiment of a foaming assembly; 
         FIG. 8  is a sectional view of a foam dispenser including the foaming assembly of  FIG. 7 ; 
         FIG. 9  is an enlarged sectional view of the nozzle portion of the foaming assembly shown in  FIGS. 7 and 8 ; 
         FIG. 10  is a sectional view of a partially assembled dispenser shown in  FIG. 8  but showing the porous foaming element and venturi ring disassembled; 
         FIG. 11  is a blown apart perspective view of a further alternate embodiment of a foaming assembly; 
         FIG. 12  is a sectional view of the foaming assembly of  FIG. 11 ; 
         FIG. 13  is a perspective view of the soap dispenser of  FIG. 1  and showing an outer housing broken away; and 
         FIG. 14  is a side view of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 to 3 , an unpressurized, non-aerosol foam dispenser is shown generally at  10 . Dispenser  10  includes a foaming assembly  12  connected to a liquid container  13 . The liquid container  13  is an unpressurized liquid container. 
     The foaming assembly  12  includes foam cone  14 , a piston  16  and a bottle seal  18 . The piston  16  and bottle seal  18  define a liquid chamber  20 . The foam cone  14 , bottle seal  18  and piston  16  define an air chamber  22 . The liquid chamber  20  is a central liquid chamber and the air chamber  22  is an annular air chamber. The foam cone  16  moves relative to the bottle seal  18 . The piston  16  is operably connected to the foam cone  14  with a press fit. An O-ring  24  slides between the piston  16  and the bottle seal  18  and provides a liquid seal therebetween. 
     The liquid container  13  is in flow communication with the liquid chamber  20 . A bottle seal valve  28  controls the inlet  30  of the liquid chamber  20 . A top hat valve  32  controls the outlet  34  of the liquid chamber  20 . 
     A porous foaming element  36  is positioned between the piston  16  and the foam cone  14 . The porous foaming element  36  has an air inlet  38 , a liquid inlet  40  and an outlet  41 . The air inlet  38  and liquid inlet  40  are spaced apart. The porous foaming element  36  has zones of different porosity. By way of example only the porous foaming element  36  has a smaller pore size zone  44  and a larger pore size zone  46 . The porous foaming element  36  may be compressible material or it may be manufactured such that the pore size varies as prescribed. By way of example only the compressible material may be sponge material. Generally as pore size decreases the foam quality changes. It has been observed that as pore size decreases the resultant foam appears smoother or richer and thus would be considered better quality foam. As air and liquid are forced under pressure through the porous foaming element  36  the foam quality improves. 
     It will be appreciated by those skilled in the art that with a compressible porous foaming element the zones of different porosity are defined by the geometry of the piston  16  and the foam cone  14 . Compression of the porous foaming element  36  is achieved during assembly. As shown in  FIGS. 3 to 5 , a variety of different configurations may be constructed such that the porous foaming element  36  has a compressed zone  44  having smaller pores and an expanded zone  46  with larger pores. The porous foaming element  36  may have a generally bow tie shape as shown in  FIG. 3  wherein the larger pore size zone  46  is around the outside and the smaller pore size zone  44  is in the center, a half bow tie at the bottom as shown in  FIG. 4  wherein the small pore size zone  44  is downstream of the larger pore size zone  46 , or a half bow tie at the top as shown in  FIG. 5 , wherein the small pore size zone  44  is upstream of the larger pore size zone  46 . Note that where the porous foaming element is made from compressible material there may be a gradual transition of pore size between the large pore size zone  46  to the small sore size zone  44 . 
     In use when the dispenser  10  is activated the foam cone  14  moves inwardly relative to the bottle seal  18  thus moving between an at rest position to an activation position decreasing the internal volume of the liquid chamber  20  and the air chamber  22  thus pressurizing the liquid and air therein and forcing the liquid and air under pressure into porous foaming element  36 . This embodiment is similar to that shown in U.S. Pat. No. 8,104,650 issued to Lang et al. on Jan. 31, 2012. 
     One advantage of the porous foaming element  36  is that it acts as both a foaming element and an anti-drip element. Thus in the embodiment described above a number of elements may be reduced. Comparing a prior art foaming component  49  shown in  FIG. 6  to the embodiment described above, most of the components are the same except that it does not include the porous foaming element  36 . Rather it includes the upstream gauze tube  50  having large gauze pores, downstream gauze tube  52  having smaller gauze pores and venturi ring  54 , all of which are not needed in the embodiments of the present disclosure. The foam cone  14 , valve  32 , piston  16 , O-ring  24 , bottle seal valve  28  and bottle seal  18  are similar to those described above with regard to foaming assembly  12 . 
     It will be appreciated by those skilled in the art that the porous foaming element described above may also be used in other type of pumps, for example dispenser  60  shown in  FIG. 10  and described in detail in U.S. application Ser. No. 13/458,318 filed Apr. 27, 2012 to Banks et al. Referring to  FIGS. 7 to 10 , dispenser  60  includes a pump or foaming assembly  62  and a liquid container  64 . Pump  62  includes a piston dome  66 , a liquid and air bore  68  and a main pump body  70 . The main pump body  70  includes an exit nozzle  72 . A porous foaming element  74  is positioned in the exit nozzle  72 . A venturi ring  76  is downstream of the porous foaming element  74 . A valve  78  is positioned in exit nozzle  72  to selectively open and close the outlet  82  of liquid chamber  80 . The liquid and air bore  68  and main body  70  define a liquid chamber  80 . The piston dome  66  and liquid and air bore  68  define the air chamber  84 . Movement inwardly of the piston dome  66  into the main body  70  decreases the volume of the liquid chamber  80  and the air chamber  84  thereby forcing under pressure air and liquid into the porous foaming element  74 . 
     The porous foaming element  74  is positioned in the exit nozzle between the liquid chamber  80  and the venturi ring  76 . The porous foaming element  74  is made of compressible material and a smaller pore size zone  86  is where the compressible material is more compressed than in a larger pore size zone  88 . The porous foaming element  74  is defined by the geometry of the exit nozzle  72  and the venturi ring  76 . In the assembly process the porous foaming element  74  is positioned in the nozzle  72  and then the venturi ring  76  is inserted into the nozzle  72 . The geometry of the venturi ring  76  is configured to create a compressed area such that there is a smaller pore size zone  86  and a larger pore size zone  88  as best seen in  FIG. 9 . Referring to  FIGS. 11 and 12 , another example of a porous foaming assembly  90  is similar to that shown in U.S. Pat. No. 5,443,569 issued to Uehira et al. on Aug. 22, 1995 but modified to include a porous foaming element  106 . 
     The porous foaming assembly  90  includes a pump head  92 , a bottle cap  94 , an air piston  96 , a piston  98  and a main body  100 . The main body  100  and piston  98  define the liquid chamber  102  and the pump head  92 , bottle cap  94 , air piston  96 , piston  98  and main body  100  define the air chamber  104 . Movement inwardly of the pump head  92  into the main body  100  decreases the volume of the liquid chamber  102  and the air chamber  104  thereby forcing, under pressure, air and liquid into a porous foaming element  106 . 
     The porous foaming assembly  90  includes a valve stem  108  and air valve  110 , a valve step  112 , liquid valve  114  and main body seal  116 . A spring  118  biases pump head  92  into an at rest position. Moving the pump head  92  into the main body  100  and into an activation position decreases the volume of the air chamber  104  and liquid chamber  102 . The shape of the porous foaming element  106  is defined by the geometry of the air piston  96  and the pump head  92  defining a smaller pore size zone  120  and a larger pore size zone  122 . 
     The dispensers described above may further include a housing. Referring to  FIGS. 13 and 14 , dispenser  10  may further include a housing  124 . The housing  124  has an actuator  126  that engages foam cone  14  such that moving the actuator  126  moves the foam cone  14 . Housing  124  may include a sensor  128  that activates the sensor response to the sensor sensing the presence of a user. 
     Various embodiments and aspects of the disclosure will be described with reference to details discussed below. The following description and drawings are illustrative of the disclosure and are not to be construed as limiting the disclosure. Numerous specific details are described to provide a thorough understanding of various embodiments of the present disclosure. However, in certain instances, well-known or conventional details are not described in order to provide a concise discussion of embodiments of the present disclosure. 
     As used herein, the terms, “comprises” and “comprising” are to be construed as being inclusive and open ended, and not exclusive. Specifically, when used in the specification and claims, the terms, “comprises” and “comprising” and variations thereof mean the specified features, steps or components are included. These terms are not to be interpreted to exclude the presence of other features, steps or components. 
     As used herein, the term “exemplary” means “serving as an example, instance, or illustration,” and should not be construed as preferred or advantageous over other configurations disclosed herein. 
     As used herein, the terms “about” and “approximately” are meant to cover variations that may exist in the upper and lower limits of the ranges of values, such as variations in properties, parameters, and dimensions. In one non-limiting example, the terms “about” and “approximately” mean plus or minus 10 percent or less. 
     As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result.