Foam dispensers which are currently offered for dispensing a liquid substance with a foam consistency (due to the mixing of air) are typically configured for manual operation. A pump assembly is attached to the neck opening of a liquid reservoir (container) and cooperating air and liquid pumps are used to introduce air and liquid into a mixing chamber or area. Manually depressing an actuator causes an air piston and a liquid piston or plunger to move (usually simultaneously or nearly so) in such a way that liquid is pumped or drawn from a liquid chamber and air is drawn from an air chamber in order to produce a foam by blending these two constituents together and forcing the combination of liquid and air through a mesh screen or other similar structure in order to produce air bubbles.
One of the considerations when designing foam dispensers of the type generally described above is the suitability of the mechanical construction for a variety of liquids. The referenced “variety” includes various chemical compositions as well as various viscosities for these chemical compositions. Another consideration is the quality of foam which is capable of being produced by the mechanical construction, the manner or method of use, and the chemical composition of the liquid. A related structural feature in terms of the quality of foam includes the number, location, and style of mesh screens which are used as part of the foam production process. The production of foam involves a blending of air and the selected liquid and essentially forcing the air through a body, stream, or sheet of liquid so as to create small air bubbles. These small air bubbles are coated with a thin film of the liquid and the surface tension of the liquid tends to maintain its coated status around the small air bubbles.
Another factor which can influence the quality of foam which can be produced by the dispenser is the speed of movement of the air piston and liquid piston or plunger. Acceleration of the two pistons up to the desired speed and maintaining that desired speed contributes to defining the quality of the foam being produced. The speed of the pistons influences the speed of the flow of air and the flow of liquid through their respective passageways to the point of initial mixing. The size of the passageways or other flow openings also has an effect on the speed of the air and liquid flows. It is though not always possible to fully inform the user of the foam dispenser of these factors with only the normal printed instructions which would typically accompany the foam dispenser. The user may not understand that speed is a factor which can influence the quality of the foam which is produced and dispensed. A still further factor which needs to be assessed in the design and construction of a foam dispenser is the overall dispenser complexity. Reduced complexity of the foam dispenser can be a contributing factor to a more reliable foam dispenser. Even if reliability is not significantly improved, reduced complexity usually means a reduced cost.
The foam dispenser structure disclosed herein, i.e., the selected embodiment, is considered to have reduced complexity and it is expected that there will be a corresponding reduced cost as compared to many prior art constructions. The selected embodiment is considered to have improved reliability relative to many prior art constructions due to its simplified construction. The reduced complexity results from simpler air flow arrangements and the elimination of any type of gadget or specialized features. Often these gadgets or specialized features simply add complexity and cost and are not always directed to the ultimate objective of producing quality foam from a variety of liquids.
The selected embodiment is designed with actuator interference with respect to the receiving collar causing an increase in the level of force required to initiate downward axial movement of the actuator. Once the interference is cleared, the level of force being applied creates an acceleration of the actuator. The actuator controls the downward axial movement of the air piston and of the liquid piston or plunger and thus the acceleration of these components is also influenced by the movement or travel of the actuator. Having this acceleration means that the desired speed is achieved sooner and the quality of the foam is improved.
The selected embodiment provides a foam dispenser with less complexity than various prior art structures by enabling a premix of the air and liquid before passing through a first mesh screen which is a part of the foamer housing. This premixing, which is similar to having an extra mesh screen at this location, achieves much the same result without the added cost and without the added complexity of requiring a third mesh screen. Another design simplification offered by the selected embodiment disclosed herein is the use of a liquid flow valve structure to help control the valving of the air flow into the premix location before entry through the first mesh screen.
A foam dispenser for dispensing a liquid with a foam consistency includes a container which is constructed and arranged to hold a volume of liquid and a pump assembly which is connected to the container. The pump assembly includes an actuator defining a foam-dispensing outlet, a collar constructed and arranged to connect to a portion of the container, the collar receiving the actuator, a body defining an air chamber and a liquid chamber, a foamer housing received by the actuator and including a mesh screen, an air piston received by the air chamber, a plunger extending through a portion of the air chamber into the liquid chamber, a movable valve pin received by the plunger, an air valve received by the piston and being constructed and arranged to control the flow of replacement air into the air chamber, and a liquid flow control structure received by the body and cooperating with the volume of liquid for controlling the flow of replacement liquid into the liquid chamber.
One feature of the selected embodiment is the presence of an interference fit between the collar and the actuator so as to require a higher force initially which results in actuator acceleration.
Another feature of the selected embodiment is using the valve pin to open both a liquid passageway and an air passageway wherein movement of the valve pin is achieved by the use of liquid flow.
For the purposes of promoting an understanding of the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated device and its use, and such further applications of the principles of the disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates.
Referring to
The
In view of the secure mechanical connection between the collar 24 and the remainder of the pump assembly 21, the threaded assembly of collar 24 onto neck 25 assembles the pump assembly 21 to and into the container 22. In the
As used herein, the terms “up”, “top”, “down”, and “bottom” each have their normal or conventional meanings based on the foam dispenser 20 being set or positioned upright with the bottom surface of the container 22 being placed on a substantially horizontal surface. While this does not preclude the user or someone on behalf of the user picking up the foam dispenser and changing its orientation as foam is being dispensed, it is felt that the more common or likely use will be in the described vertical orientation on a substantially horizontal surface. Accordingly, this orientation is what has been used to define the terms mentioned above. This is also the orientation used for all of the drawings.
The actuator 33 might also be referred to as a nozzle or dispensing nozzle since this single piece component part of the pump assembly 21 is the component part used both as an actuator to initiate the production and delivery of foam and as the means for actually dispensing the foam through an outlet opening. As the foam is produced, it travels through the nozzle portion 33a and then out through dispensing opening 34. Nozzle portion 33a defines the shape and size of the dispensing opening 34. Hereafter, this component part will simply be referred to as actuator 33.
With continued reference to
The annular collar 24 is further illustrated in
With continued reference to
With regard to some of the terminology being utilized in the description of the first selected embodiment, the exemplary shape of the outer wall 82 of the actuator 33 and the exemplary shape of the opening defined by the raised actuator lip 52 of the collar 24 have been described as oval or elliptical. Since the term “oval” would typically denote a continuous annular form which is not necessarily circular, that provides one option for the first selected embodiment. However, an elliptical shape has a more precise geometric definition and is symmetrical with regard to the major and minor axes. Accordingly, the first selected embodiment is elliptical in shape as to these components and that is the term to be used hereinafter. The elliptical shape also means that the actuator 33 will install into the collar in one of only two orientations which are 180 degrees apart. In order to have these two assembly options available, and in order to position the open end 28 in a corner of the container, the two alignment portions 58 must be 180 degrees apart.
As would be understood, the series of threads on neck 25 are constructed and arranged, including the start location of the series of threads relative to the body of container 22, in order to control the orientation or positioning of collar 24 once it is fully threaded onto the neck. This control of the threads and the threaded engagement enables a relatively precise positioning or orientation of the elliptical opening 24a in a side-to-side direction relative to the wider front panel portion of container 22. This means that the major axis of the elliptical shape of opening 24a is generally parallel with the plane of the front panel portion (i.e., the front label surface) of container 22.
When the actuator 33 is assembled into collar 24, the cooperating elliptical shapes cause the nozzle portion 33a to be directed sideways relative to the front panel portion, as illustrated in
It is to be understood that an oval shape for the actuator body and for the receiving opening would also be acceptable and consistent with the remaining structures disclosed herein by making the necessary modifications to the alignment features. As noted, one alternative construction is to change these elliptical shapes to circular (i.e., cylindrical). This alternative construction is illustrated in
The upper end 72 of outer wall 63 is formed with a flange 73 which includes the two alignment projections 59. Assuming proper alignment of the projections 59 into or with the two alignment portions 58, flange 73 is constructed and arranged to snap into channel 54. In addition to having compatible sizes and shapes, radially inward rib 74 of collar 24 provides the reduced clearance for the snap-fit assembly. The outer wall 63 defines therein an air vent hole 63a. The six (6) gussets 40b are optionally molded on the concave side of bend 68 for reinforcement of wall 64 and overall stabilizing.
The gasket 41 is further illustrated in
The actuator 33 is further illustrated in
With continued reference to
The inner wall 81 of actuator 33 is generally cylindrical. The outer wall 82 of actuator 33 has an elliptical shape which is constructed and arranged in cooperation with interior opening 24a of collar 24. The lower end 93 of outer wall 82 is formed with an outwardly protruding portion 94 which is preferably of a continuous annular form corresponding to the elliptical shape of outer wall 82. Protruding portion 94 has a bulbous outer surface which contacts the inner surface 52a of the raised actuator lip 52. Dimensionally, the size of the outer surface of protruding portion 94 is larger than the size of the inner surface of the raised actuator lip 52. By creating these two contacting surfaces with this dimensional interference (i.e., an interference fit in the up position), a pre-designed force level is required to break loose the actuator 33 from this interference fit and the temporary “capture” by the collar 24.
As is illustrated in
It is also envisioned that the outwardly protruding portion 94, in lieu of a continuous annular form, in this embodiment elliptical, could be formed in sections spaced apart around the surface of the outer wall 82. A further design variation is to mold or machine a detent or detents into the inner surface 52a of the actuator lip 52. Such a detent or detents would be sized and shaped to receive protruding portion 94, similar to a ball detent arrangement. A further design variation on this alternative design option is to reverse the male/female forms of the ball detent. This would mean a detent or detents formed in the outer wall 82 of the actuator 33 and a protruding portion (or portions) which would typically have a bulbous shape, formed on the inner surface 52a of the actuator lip 52. Even if detents are not used, the current embodiment which is illustrated could have the roles reversed by forming the bulbous projection on the collar and modifying the shape of the lower end of the outer wall 82 in order to be compatible and provide the desired interference fit.
The interference which is designed into the relationship between collar 24 and actuator 33, referring now to surface 52a of collar 24 and outwardly protruding portion 94 of actuator 33, is essentially the same when the elliptical contours of the first embodiment are changed to cylindrical contours for the second embodiment. The “acceleration” of the actuator which is described in greater detail below is essentially the same, whether the cooperating contours are generally elliptical or the cooperating contours are generally cylindrical.
Referring now to
Wall 101 has an upper portion 101a which is a larger outside diameter extension of wall 87 and a lower portion 101b. The interior surface 101c of portion 101a is constructed and arranged with a series of six (6) equally-spaced axial splines 101d with air flow channels 101e being defined therebetween by the axial splines. The enlarged inside diameter at the lower free end of portion 101b is constructed and arranged to receive the radial rib 109 of the plunger 42. The larger diameter of portion 101a relative to the outside diameter of wall 87 creates a relatively narrow radial shelf 101f which is contacted by the lower edge 86a of the inner wall 81 of actuator 33, during manual axial depression of the actuator 33 to initiate the production of foam. The corner junction 56 of wall 99 and connecting section 103 defines a plurality of spaced-apart air vent openings 110. These opening are closed off by a skirt portion of one-way valve 44. A positive pressure within air chamber 30 on the valve 44 skirt during the dispensing stroke seals these air vent openings 110 closed. A sufficient negative pressure within air chamber 30 pulls the one-way valve skirt 44c away from the air vent openings 110, allowing air from the atmosphere to flow into the air chamber 30 by way of the air vent openings 110.
A second embodiment for the arrangement of and cooperation between piston 243 (based on piston 43 of the first embodiment) and one-way valve 244 is illustrated in
Cooperating with piston 243 and the “new” location for the air vent openings 245 of this alternative embodiment is an alternative embodiment for the one-way valve 244 (generally corresponding to one-way valve 44 of the first embodiment). The construction and arrangement of one-way valve 244 is described further in conjunction with the discussion regarding
Shelf 101g defines central aperture 106. On the upper surface of shelf 101g there are three abutment ribs 101h which are constructed and arranged to cooperate with the positioning of foamer housing 45. These abutment ribs 101h maintain the desired minimum spacing between shelf 101g and mesh screen 46. On the lower (opposite) surface of shelf 101g there are six abutment ribs 101i. These lower abutment ribs 101i are constructed and arranged to cooperate with the valve pin 39 so as to prevent travel of the valve pin head up against shelf 101g which would effectively close off central aperture 106.
The six axial splines 101d (see
Referring now to
The body 45a is a single piece, molded part, preferably fabricated out of polypropylene with a defined generally cylindrical hollow interior.
The standard mesh of screen 46 has a mesh strand centerline-to-centerline dimension of approximately 0.22 mm and an opening size dimension of approximately 0.165 mm (square). The fine mesh of screen 47 has a centerline-to-centerline dimension of approximately 0.11 mm and an opening size dimension of approximately 0.086 mm (square). Each mesh screen is generally circular with a thickness of approximately 0.10 mm. The material options include nylon, HDPE, polypropylene and polyester and the preferred material is nylon.
Referring now to
Referring now to
Referring now to
The shape and enlargement of tip 126 relative to section 124b allows a retained snap-fit into the top portion of spring clip 38. The head 125 is constructed and arranged with lower frustoconical portion 128, a flange 129, and a generally cylindrical wall 130 connecting portion 128 with flange 129. Frustoconical portion 128 is sized and shaped to fit generally flush against frustoconical surface 116 of the plunger 42 when the valve pin 39 is in its down and seated position prior to initiation of the foam production process. The spring is constructed and arranged so as to place a modest preload on plunger 42 upwardly against head 125 of valve pin 39. The lower end of spring 37 pushes against flange 137 of spring clip 38. This spring force in turn draws the upper end of spring clip 38 against tip 126. The upper end of spring 37 pushes up on plunger 42 which pushes up on valve pin 39 and thus the spring preload. As the actuator 33 is depressed, the preload is released, allowing the valve pin 39 to essentially float with plunger 42. Without the spring preload, the flow of liquid which is used to lift or raise valve pin head 125 off of the valve seat is able to create a suitable flow path for that liquid. Since the spring preload has been released, the force due to liquid flow only has to exceed the weight of the valve pin 39.
Flange 129 has a continuous outer annular surface 129a which is generally cylindrical without any radial openings therethrough. Radially inwardly of surface 129a are axial flow openings 129b which are defined by the construction and arrangement of flange 129. The lower surface of flange 129 is constructed and arranged to seat on the upper surface 131 of plunger 42 concurrently with portion 128 seating on surface 116. In this seated position prior to the depression of actuator 33, the upper portion of each spline 101d, which extends above the upper surface 131 of plunger 42, is closed or blocked off by the outer annular surface 129a, (see
Referring now to
The interior of top portion 136 is constructed and arranged to receive tip 126 of valve pin 39. The tapered shape of tip 126 enables an easy insertion and resulting snap-fit which allows the shaping of the interior of top portion 136 to capture and retain tip 126 while still permitting relative axial movement between section 124b of valve pin 39 and the top portion 136 of spring clip 38, see
The assembly of foam dispenser 20 is accomplished in sequential stages using subassemblies. One of the subassemblies is foamer housing 45 comprised of the two mesh screens 46 and 47 which are welded to the housing body 45a. Another subassembly (the valve pin subassembly) includes spring 37, spring clip 38, valve pin 39, and plunger 42. A portion of spring 37 is received within plunger 42 and a portion of spring 37 is received by spring clip 38. The valve pin 39 seats within plunger 42 with lower tip 126 received by spring clip 38. In the context of this description of the subassemblies and the assembly of foam dispenser 20, piston 43 and piston 243 are considered to be generally equivalent to each other. Likewise, one-way valve 44 and one-way valve 244 are considered to be generally equivalent to each other relative to the subassemblies and the assembly sequence. However, it is to be noted that piston 243 and one-way valve 244 are constructed and arranged to be used together as part of the second embodiment of pump assembly 221.
With these first two subassemblies completed, the next stage includes assembly of the foamer housing into piston 43 and the assembly of the one-way valve 44 into piston 43. This piston subassembly receives the valve pin subassembly and these two subassemblies are received by body 40. The one-way valve 44 fits up into piston 43 with an interference fit which is continuous in annular form and seals up into the interior corner of piston 43.
One preliminary step prior to body 40 receiving the two subassemblies is to place ball 36 on the valve seat 67. Another preliminary step in terms of the assembly equipment which is preferably used is to located the body in the desired location and with its desired orientation. Projection 40a is sized and shaped to fit within a receiving pocket or recess in the automated assembly equipment in order to achieve the desired location and the desired orientation. The subassembly which is created after this last stage is assembled into collar 24 and actuator 33 is snapped into collar 24. This assembly step seats the foam housing 45 up into the interior of the actuator 33, as previously explained.
The final step prior to threaded connection of the pump assembly 21 to the container 22 is to insert the upper end of the dip tube 26 into the body 40 (interference fit). The insertion of the dip tube completes the pump assembly 21. Since it is necessary to add the desired liquid into the container 22, this step is typically performed by a filler prior to the step of connecting the pump assembly 21 to the container. A further required step is to apply the overcap 23. The overcap 23 can be snapped onto the collar prior to connection of the pump assembly 21 to the container 22. Since each pump assembly 21 is not uniquely matched with a corresponding container 22, at least not prior to the addition of liquid, the pump assemblies 21 are able to be shipped to the filler, either with the containers, when coming from the same source of supply, or separately, when coming from different sources of supply.
In use, the status of foam dispenser 20 begins generally as illustrated in
After this initial priming stroke, the subsequent downward axial travel of piston 43 and plunger 42 (the second overall stroke) reduces the open volume size of the air chamber 30 and the open volume size of the liquid chamber 31, respectively. The designed volume sizes of air chamber 30 and liquid chamber 31 have a size ratio of approximately 9.5:1 which essentially governs the air-to-liquid ratio by volume. The downward axial travel of piston 43 and plunger 42 reduces the air chamber 30 and liquid chamber 31 volumes proportionately so as to maintain approximately this same ratio. The reduction in volume means an increase in pressure. In the air chamber 30, this internal pressure seals the tapered skirt 44c of the one-way valve 44 against the inside surface of the body, preventing any noticeable escape of air through or across this interface. The internal pressure forces the volume of air in the air chamber 30 to seek an exit passageway or exit aperture.
The downward axial movement of plunger 42 pressurizes the liquid chamber 31 and forces the pre-charge of liquid contained therein, due to the initial charging stroke, to seek a flow opening or passageway in order to exit from the liquid chamber 31. As would be understood, the pressurizing of the liquid chamber pushes ball (valve) 36 against the frustoconical seat 67 formed by body 40. Structurally, a liquid passageway is provided through the interior defined by intermediate wall 64 of body 40. This upward flow of liquid passes through spring 37 and through the interior of plunger 42. This liquid flow passageway is defined by the inside diameter of plunger 42 and by the outside diameter of elongated body 124 of valve pin 39. When this liquid flow reaches the head 125 of valve pin 39 (as seated on plunger 42), the liquid pressure acts on the lower portion 128 of head 125. When the liquid pressure force, due to the flow of liquid, exceeds the weight of the valve pin 39, the valve pin head 125 is raised or lifted off of the frustoconical seat 116. This movement opens a passageway around head 125, allowing a flow of liquid to enter space 145 (see
When the valve pin head 125 moves in an axially upward direction off of frustoconical surface 116, the valve head flange 129 moves out of its blocking position against splines 101d. This movement creates an air flow passageway for the air under pressure within the air chamber 30 to escape. It is the flow of liquid which lifts or raises the valve pin head 125 and this action creates not only a liquid flow passageway around the valve head 125, but the lifting action caused by the flow of liquid also creates an air flow passageway through the splines 101d and through the valve head flow openings 129b into space 145. The single action of liquid flow at a sufficient “lifting” pressure or force, in cooperation with the valve pin head 125, creates both a liquid flow passageway and then an air flow passageway (see
The force of liquid flowing up against the valve pin head 125 causes the valve pin head 125 to lift off of frustoconical surface 116. Accordingly, there is some amount or volume of liquid which actually reaches space 145 before the leading edge of the air flowing past the splines 101d is able to reach space 145. In turn, this means that there is a flow of air into and through the initial volume of liquid before this air-liquid mixture flows through central aperture 106 on its way to foamer housing 45. This initial flow of air into the initial volume of liquid in space 145 functions similar to the mixing and aeration achieved by a mesh screen. The timing of the initial liquid flow and the initial air flow subsequent thereto which move into space 145 causes the combination of flows to functionally behave to some extent or degree similar to a mesh screen without the cost of providing what would be a third mesh screen. The use herein of the term “mixing” is intended to refer to aeration of air and liquid whereby air bubbles are created and some portion of these are coated with a thin film of the corresponding liquid.
The production of foam involves essentially the creation of small air bubbles which are coated with a thin layer of the liquid, allowing the liquid surface tension to maintain the liquid coating, even as larger bubbles are made smaller as that mixture passes through a subsequent mesh screen. Starting with what would preferably be a planar stream of liquid, the air is forced through the liquid so that the aeration into smaller bubbles is accomplished in the presence of the liquid, which in turn coats a majority of those bubbles as the bubbles are formed. As larger bubbles are split or aerated into smaller bubbles, the liquid continues to coat the outer surface and cling to that outer surface due to the surface tension of the liquid.
The air-to-liquid ratio (by volume) is controlled principally by the volumes of the air chamber 30 and the liquid chamber 31. To a lesser degree, the flow openings or passageways are a factor. It is considered that a high quality foam will be produced with an air-to-liquid ratio (by volume) in the range of from approximately 9.5:1 up to approximately 10.0:1 or perhaps higher.
With a continuation of the downward stroke of actuator 33, the air and liquid mixture is forced from and through space 145 into foamer housing 45. The travel of the air and liquid mixture into and through housing 45 begins (i.e., enters) with the standard (coarser) mesh screen 46 and then exits through the finer mesh screen 47. The exiting foam is dispensed out through nozzle portion 33a and specifically out dispensing opening 34. These three foam production stages progressively create smaller and smaller bubbles and ultimately achieve what is regarded as quality foam.
Another factor which has a bearing on the quality of foam is the speed of the air-liquid mixture as it is pushed through the mesh screens 46 and 47. Slow pumping of the liquid and air mixture is likely to flood the first mesh screen 46 and the result is a poorer quality foam or no foam.
As described, the interference fit between the collar 24 and actuator 33 causes a greater actuation force to be exerted over what would otherwise be required to actually depress the actuator, assuming no interference fit. Once the outwardly protruding portion 94 of the actuator 33 travels downwardly passed the interference surface of actuator lip 52, the actuator 33 to some extent breaks free and experiences an acceleration which helps to generate the desired speed for the movement of the piston 43 and thus the desired speed for the flows of liquid and air. This interference between the collar 24 and actuator 33 and the resulting acceleration can be further described by thinking of what happens when a refrigerator door is opened. Once the magnetic force is overcome, the door experiences a brief period of acceleration due to the added force which has been applied and is now higher than needed to move the door. While this higher force was required initially to overcome the magnetic force, once that magnetic force or attraction is broken, the door breaks free and there is a brief period of acceleration. The flow speed of the liquid and air constituents is also influenced to some degree by the size of the flow openings and passageways.
As the downward stroke of the actuator continues, the compression force on spring 37 increases, thereby storing kinetic spring energy for the spring return stroke which will move the actuator 33 and the related components back to their upper starting position as illustrated in
The negative pressure in the air chamber due to the upward movement of piston 43 pulls tapered skirt 44c away from the inside surface of wall 99 and thereby uncovers the air vent openings 110. Thereafter, replacement air is able to enter the air chamber 30 by way of the separation gap or space 97 between the collar 24 and the actuator 33 (see
Referring now to
Referring now to
As noted, while the principle change to piston 43 in creating piston 243 was to change the locations for the plurality of air vent openings 245, minor shape changes were made to various wall portions and sections. These are all illustrated in
Referring now to
While the preferred embodiment of the invention has been illustrated and described in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that all changes and modifications that come within the spirit of the invention are desired to be protected.
This application is a continuation-in-part of application Ser. No. 12/776,665, filed May 10, 2010, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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Parent | 12776665 | May 2010 | US |
Child | 12875178 | US |