Plural chambered squeeze tube

Abstract

An elongated, flexible walled, hand squeezable tube having first and second chambers for storing first and second fluids, respectively. The first chamber has a generally cylindrical configuration. A compressible and resilient interface for the first and second fluids is positioned within and movable along the axis of the first chamber. The interface compensates for variations in the cross-sectional size and configuration of the generally cylindrical first chamber by automatically assuming the cross-sectional size and configuration thereof as the interface moves along the axis of the chamber in response to hand squeeze pressure exerted upon the flexible walled tube. A dispensing mechanism is fluidly coupled to the two chambers to provide outlet passageways therefrom. In a preferred embodiment, the dispensing mechanism can be adjusted to selectively discharge the fluids and to vary the proportions thereof.

Parent Case Text

This is a continuation of application Ser. No. 245,956 filed Apr. 20, 1972, now abandoned.

Description

BACKGROUND OF THE INVENTION

The present invention relates to dispensers in general and more particularly, to a hand squeezable, plural chambered dispensing tube which utilizes a slightly compressed and resilient interface acting within a generally cylindrical chamber.

The art of plural chambered "hand squeezable" tube dispensers is quite extensive and relatively old. Early examples of such dispensers are found in Hopkins, U.S. Pat. Nos. 1,535,529; 1,639,699; and 1,699,532 issued Apr. 28, 1925; Aug. 23, 1927; and Jan. 29, 1929, respectively. More recent and also representative examples of the hand squeezable tube art include Bloom, U.S. Pat. No. 2,959,327 issued Nov. 8, 1960; Gangwisch, U.S. Pat. No. 3,200,995, issued Aug. 17, 1965; and Farrar, et al. U.S. Pat. No. 3,217,931, issued Nov. 16, 1965.

Plural chambered dispensers which utilize a movable diaphragm follower to force out one material are shown in the following United States Patents: Sperro, U.S. Pat. No. 2,873,887 issued Feb. 17, 1959; Maraffino, U.S. Pat. No. 2,914,220, issued Nov. 24, 1959; Taylor, U.S. Pat. No. 2,944,704, issued July 12, 1960; Sajada, U.S. Pat. No. 3,002,658, issued Oct. 3, 1961; Gallo, U.S. Pat. No. 3,042,263, issued July 3, 1962; and Gallo, U.S. Pat. No. 3,182,860, issued May 11, 1965. Similar hand squeezable plural chambered dispensers having a fixed, but flexible diaphragm are also known in the art, e.g., Moskovitz, U.S. Pat. 3,031,104 issued Apr. 24, 1962.

The hand squeezable, plural chambered tube dispensers illustrated in the prior art listed above are not particularly well-suited for modern day plastic molding techniques and subsequent high speed assembly and filling line operations. Furthermore, a number of new products have been proposed which are predicated upon the mixing of two chemical active agents at the point of use. The aforementioned plural chambered tube dispensers do not provide significant means to prevent cross-contamination of these two reactive ingredients, not only before and during, but also after each dispensing operation.

Additionally, new product concepts have been identified that expand upon the concept of plural chambered tube devices but which require the ability to selectively discharge the fluids and vary the proportions thereof.

When one approaches the problem of effectively protecting against product cross-contamination within a plural chambered tube produced by mass production techniques a number of variables are recognized which contribute to the problem, such as product viscosity, injection molding techniques, etc. Since the prior art was primarily concerned with relatively viscous and compatable materials such as toothpastes and striping ingredients, cross-contamination of the stored materials was not a major problem. However, with the use of thinner lotions or chemically active agents, greater precautions should be taken to guard against the occurrence of cross-contamination. An effective interface is now needed which will form a sliding, yet consistently sealing fit despite the tolerances and irregularities inherent to today's high speed molded plastic parts.

It is, accordingly, a general object of the present invention to provide an improved hand squeezable, plural chambered, dispensing tube.

It is a specific object of the present invention to provide a hand squeezable, plural chambered dispensing tube which substantially eliminates cross-contamination of the dispensed materials during the entire life cylce of the dispenser.

It is another object of the present invention to provide a hand squeezable, plural chambered dispensing tube which permits selective discharging of the stored materials.

It is still another object of the present invention to provide a hand squeezable, plural chambered, dispensing tube which permits variable ratio dispensing of the stored materials.

It is a feature of the present invention that the functional elements of the dispensing tube when assembled have the desired degree of fit and movement yet are still compatable with the dimensional tolerances common to present day plastic molding techniques.

It is still another feature of the present invention that the functional elements thereof can be readily fabricated, assembled and filled using present day standard techniques and equipment.

It is still further feature of the present invention that hangup of one or both stored materials is minimized.

These objects and other objects and features of the present invention will best be understood from a detailed description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings, in which:

FIG. 1 is an exploded view in partial cross-section showing the structural elements of the hand squeezable, plural chambered tube dispenser;

FIG. 2 is an enlarged view in cross-section showing the dispensing mechanism of the dispensing tube in the closed position;

FIG. 3 is a view similar to that shown in FIG. 2 illustrating the dispensing mechanism in the position for dispensing one of the two stored materials;

FIG. 4 is another view in cross-section similar to that shown in FIG. 2 depicting the dispensing mechanism in position for dispensing both of the stored materials;

FIGS. 5 through 8 show in cross-section and in sequence another embodiment of the dispensing mechanism of the tube which provides for variable ratio dispensing of the two dispensed materials; and,

FIGS. 9 through 12 show in cross-section and in sequence still another embodiment of the dispensing mechanism for varying the ratio of the dispensed materials.

Turning now to the drawings and particularly to FIG. 1 thereof, there is shown in exploded and cross-sectional view a plural chambered, hand squeezable dispensing tube constructed in accordance with the present invention and indicated generally by the reference numeral 10. The squeeze tube 10 comprises four major components: a conventional, flexible walled, hand squeezable tube 12; a tubular insert 14 which defines a generally cylindrical first chamber 16; an interface 18 formed of a compressible and resilient material which is positioned within and movable along the axis of the cylindrical chamber 16; an outsert 20; and, an adjustable overcap 22.

A removable cap 24 may be supplied with the dispensing tube 10 as shown in FIG. 1 if desired. However, it should be understood that the removable cap 24 is optional and does not form a part of the invention.

The first chamber 16 defined by the tubular insert 14 is used for storing a first dispensing material or fluid. For purposes of clarity, the material stored within the first chamber 16 has been omitted from the drawings. The elongated, flexible walled tube 12 defines a second chamber 26 for storing a second dispensing material which also has been omitted from the drawing for purposes of clarity. It will be appreciated by those skilled in the art that a variety of types of materials or fluids can be stored in the first and second chambers 16 and 26, respectively. Typically, the dispenser can be used for dispensing liquids of widely varying viscosities including gels, pastes, and creams and lotions.

Recently a number of products have been proposed which have variable product characteristics depending upon the mixing ratios of two materials. For example, variable color hair dyes and bleaches can be produced by varying the ratios of a "concentrate" and "main solution." The terms "concentrate" and "main solution" are used herein for purposes of descriptive convenience and by way of illustration only and should not be construed as limiting the types of materials which can be stored in the first and second chambers of the dispensing tube 10. For example, the concentrate and main solution both can be in the form of liquids, creams, gels, lotions, etc.

Looking at FIG. 1, it can be seen that the volume of the first chamber 16 is substantially smaller than the volume of the second chamber 26. Using the terminology of concentrate and main solution, the concentrate is stored in the smaller first chamber 16, while the main solution is stored in the larger chamber 26. Normally, the concentrate fill in chamber 16 would be approximately 10 to 20 percent of the total tube capacity. However, other fill ratios can be employed to accommodate the specific requirements of the product concept.

A variety of materials can be used to fabricate the major components of the dispensing tube shown in FIG. 1 subject to a number of constraints, such as, cost, aesthetics, strength and other physical characteristics and the compatability with the concentrate and main solution, etc. Thus, for example, the tube 12 can be formed from a low density polyethylene and molded as a conventional injection headed tube. The tubular insert 14 is preferably made of polypropylene while the interface 18 is made of a moderately low density polyethylene in order to obtain the desired compressibility and dimensional memory for the interface. The fact that the interface 18 is both compressible and resilient permits the interface to conform to or assume the cross-sectional size and shape of the generally cylindrical first chamber 16.

It will be appreciated by those skilled in the molding art that the dimensional tolerances of the molded insert 14 are in the order of .+-. 10 thousandths of an inch for a chamber having an inside diameter of approximately 11/2 inches. Additionally, the interface when fabricated exhibits dimensional variations of approximately .+-. 10 thousandths of an inch. Given the variations in the molded diameter of the first chamber 16 and the size of the interface 18, the interface must have some elasticity to compensate for these variations in order to provide a leakproof interface between the materials contained in the first and second chambers 16 and 26, respectively.

In the preferred embodiment, the interface 18 comprises a low density, closed cell foamed polyethylene. An example of a suitable foam polyethylene for the interface 18 is sold by the Dow Chemical Company under the trademark "Ethafoam" and the type identification of No. 220. The closed cell, foamed plastic interface 18 is die cut to the desired diameter. The die cutting operation leaves a plurality of broken cell walls adjacent to the chamber wall which provide the requisite sealing and skrimming function as the interface moves along the axis of the generally cylindrical first chamber 16. Although the interface 18 has been shown in FIG. 1 with a solid lateral surface 18a for purposes of clarity, it will be appreciated that the surface is relatively rough because of the myriad cut walls of the closed cell foam.

The interface 18 functions as a dimensional tolerator to compensate for variations in the inside diameter of the first chamber cylinder 16 caused by normal variations in the plastic molding process. These variations may be intentional, i.e., draft angle and/or inherent, i.e., shrinkage. The minimum outside diameter of the circular interface 18 is designed to be at least equal to the maximum tolerated molded inside diameter of the first chamber 16. Under most circumstances, the outside diameter of the circular interface 18 will be greater than the maximum inside diameter of the first chamber, thereby compressing the interface when the interface is inserted in the chamber as shown in FIG. 1. The resiliency or memory of the interface when in a slightly compressed state acts to constantly expand and contract and change its cross-sectional size and shape to assume the cross-sectional size and shape of the cylindrical chamber 16. It will be appreciated that even in the situation where the outside diameter of the interface is exactly equal to the nominal diameter of the first chamber 16, an effective seal between the two viscous fluids will be caused by the "zero" clearance all along the distance of the broken cell walls in the lateral surface 18a which constitutes the length or "height" of the cylindrical interface 18. Migration of the two viscous fluids is inhibited by the zero clearance path between the two fluids. Any fluid migration which does occur is absorbed by the reservoirs formed by the broken cell walls.

The outsert 20 is molded preferably from a low density polyethylene while the adjustable overcap 22 is formed from polypropylene. The alternating sequential arrangement of the relatively soft low density polyethylene and the relatively hard polypropylene for the major components of tube 12, insert 14, outsert 20 and overcap 22 is employed to facilitate the fit and assembly of these components.

Other materials besides a low density polyethylene can be used for tube 12. For example, conventional metal squeeze tubes or a laminated combination of plastic and metal foil can be used.

The flexible walled tube 12 is formed with a thicker, relatively rigid, threaded male neck portion 28 which mates with the corresponding threaded female portion 30 of the adjustable overcap 22. A plurality of upstanding supporting ribs 32 are positioned circumferentially around the inner end of the threaded neck portion 28. These ribs support the tubular insert 14 in the assembled position and define a plurality of fluid channels 34 through which the main solution passes during the dispensing operation.

In the preferred embodiment, the tubular insert 14 is formed with relatively rigid walls to prevent distortion by accidentally squeezing. If not prevented, the accidental squeezing of the tubular insert 14 could allow the concentrate in chamber 16 to be dispensed by itself and/or sufficiently distort the interface to destroy the sliding seal between the lateral surface 18a of the cylindrical interface and the inner wall surface 14a of the insert 14. However, it should be understood that the same protection can be achieved by making the walls of the tube 12 relatively rigid in the portion of the tube surrounding the insert 14 by adding a rigid sleeve in the tube in this area or by other means.

The preferably rigid walled, insert 14 has a plurality of separate or integrally molded, outwardly extending ribs 36 which together with the inner wall surface 12a of the tube 12 define a plurality of fluid channels 38. The channels 38 fluidly connect the second chamber 26 with the fluid passageways 34 so that when the flexible walled portion of the tube 12 is squeezed, the main solution in chamber 26 will pass downwardly around the outside of insert 14 and through the fluid passageways 34 into a neck portion bore 40.

Positioned within the threaded neck portion bore 40 is an extension or neck 42 of the walled insert 14 which is in fluid communication with the concentrate chamber 16 at one end and which terminates at the other end in a discharge orifice 44. The insert extension 42 is held in spaced relation with respect to the walls of bore 40 by means of a plurality of circumferentially space, outwardly extending spacer ribs 46. The open areas between the spacer ribs 46 form a corresponding plurality of main solution fluid passageways extending downwardly through the threaded neck portion bore 40.

Referring now to both FIGS. 1 and 2, it can be seen that the outsert 20 is fitted over the threaded neck portion 28 and snap fitted within the insert neck 42. The female portion of the snap fitting connection is provided by means of a snap fit ring 48 located within bore 50 of the insert neck.

The outsert 20 preferably is molded as a single unit having an outer shell ring 52, an inner, hollow nozzle element 54 and a plurality of webs 56 which support the nozzle element 54. The upper end of the nozzle element 54, as viewed in the drawings, has an outwardly extending shoulder 58 which functions as the male end of the snap fitting when the outsert nozzle element 54 is pressed into the insert neck portion 42 during assembly of the tube components. The assembled configuration of these elements can best be seen in the cross-sectional view of FIG. 2.

The lower or discharge end of nozzle element 54 has at least one concentrate metering slot 60 which is formed in the inner wall surface of the nozzle element. Similarly, at least one main solution metering slot 62 is formed in the outer surface of the nozzle element. These metering slots are used to control the relative proportions of the dispensed concentrate and main solution as will be explained below in greater detail.

The adjustable overcap 22 has a sealing plug 64 which is supported by a plurality of webs 66. The inner end of the sealing plug 64 is tapered to provide a self-centering action during the assembly of the adjustable overcap on the threaded neck portion of tube 12. Referring to FIG. 2, it can be seen that in the "Closed" position shown therein, the sealing plug 64 is positioned within bore 68 of the outsert nozzle 54 thereby sealing the concentrate metering slot 60.

The basic sealing of the main solution in the "Closed" position is obtained by means of a flexible sealing ring 70 located in the overcap 22. This ring seats itself in the "Closed" position against an outer tapered surface 72 on the end of the outsert nozzle 54 and thereby limits the tightening rotation of the overcap.

The adjustable overcap also has an inwardly extending flexible sealing ring 74 which operates in conjunction with the outer surface of the outsert nozzle element 54 to provide an annular point seal for the main solution primarily during dispensing. An outwardly extending skrim ring 76 is provided on the outer ring element 52 of the outsert to inhibit leakage of the main solution into the molded threads of the tube neck and the overcap.

Looking now at the sequential cross-sectional views of FIGS. 2, 3, and 4, FIG. 2 illustrates the "Closed" position of a dispensing tube (together with the optional, removable cap 24); FIG. 3 shows the setting of the adjustable overcap 22 for dispensing only the main solution; and FIG. 4 illustrates the setting of the overcap for dispensing both the main solution and the concentrate. Expressed in slightly different terms, the FIG. 2 setting is the OFF position, FIG. 3 is the main solution or SINGLE setting and FIG. 4 is the main solution and concentrate or BOTH setting.

Since these settings are achieved by rotating the adjustable overcap 22 about the tube axis thereby effecting a downward travel of the overcap, as viewed in the drawings, the relative setting of the dispenser can be indicated by means of the angular position of a pointer 78 on the overcap with respect to one or more reference indicia 80 located on the tube 12. The reference indicia 80 or graphic indicators can be marked with suitable colors, letters, and numbers and the like to indicate the corresponding setting of the adjustable overcap.

In order to dispense either the main solution or a combination of the main solution and the concentrate, the adjustable overcap is rotated by the user to the appropriate setting. Assuming that the cap is set for dispensing only the main solution, when the flexible wall of tube 12 are squeezed, the main solution in chamber 26 will flow downwardly through fluid channels 38 and 34 into the threaded neck portion bore 40. The main solution then passes between the outsert supporting webs 56 through the main solution metering slot 62 and finally past the sealing plug supporting web 66.

If the overcap is now rotated to the main solution and concentrate setting as shown in FIG. 4, and the flexible walled tube 12 is squeezed, the squeezing pressure is transmitted through the main solution in chamber 26 to the movable foam plastic interface 18, causing the interface to move downwardly, as viewed in the drawings. The downward, axial travel of interface 18 within the generally cylindrical chamber 16 forces the concentrate in chamber 16 into the insert neck bore 50, through the outsert nozzle bore 68 and its associated concentrate metering slot 60 and finally past the sealing plug supporting webs 66. The main solution travel path is the same as previously described in connection with the main solution or SINGLE setting.

It should be noted that in the embodiment disclosed in FIGS. 2 through 4 only one concentrate metering slot 60a is employed, together with a plurality of circumferentially spaced equal length main solution metering slots, two of which are shown in the Figures and identified by the referenced numerals 62 and 62b. This arrangement provides for a fixed ratio dispensing of the main solution and concentrate. It will be appreciated that the ratio of the main solution and concentrate can be changed by altering the length, width and/or number of the concentrate and main solution metering slots 60 and 62, respectively. For example, the amount of main solution dispensed with respect to the dispensed concentrate can be varied, as shown in FIGS. 5 through 8, or the amount of concentrate can be varied with respect to the amount of dispensed main solution as shown in the embodiments depicted in FIGS. 9 through 12.

Referring to the first sequence illustrated in FIGS. 5 through 8, it can be seen that there are two equal length concentrate metering slots 60a and 60b. Although two slots 62a and 62b are provided for metering the main solution, these slots are of unequal length. FIG. 5 illustrates the closed setting for this embodiment of the hand squeezable dispensing tube. When the adjustable overcap is rotated and thereby moved downwardly to the first setting as shown in FIG. 6, only the main solution metering slot 62a is opened to allow a predetermined amount of the main solution to exit from the dispenser. Further rotation or downward travel of the adjustable overcap 22, shown in FIG. 7, opens the two concentrate metering slots 60a and 60b. In this setting, both the concentrate and main solution are dispensed in a ratio which is determined by the relative sizes of the main solution metering slot 62a and the concentrate metering slots 60a and 60b. If the adjustable overcap 22 is again rotated, the cap will travel downwardly to the position shown in FIG. 8. At this position, a second main solution metering slot 62b is opened thereby increasing the amount of dispensed main solution with respect to the amount of dispensed concentrate.

It is also possible as noted above to vary the amount of concentrate with respect to the amount of dispensed main solution. This particular embodiment is illustrated in the sequential cross-sections shown in FIGS. 9 through 12. FIG. 9 illustrates the embodiment in the closed position with the optional cap 24 shown in dotted form. Note that in this configuration, the main solution metering slots 62a and 62b are of equal length. However, the two concentrate metering slots 60a and 60b are of unequal length so that the slots will be exposed sequentially as the adjustable overcap 22 moves in a downwardly direction as viewed in the drawings. FIG. 10 illustrates the main solution only setting for the dispensing tube with only the main solution metering slots 62a and 62b open. FIG. 11 shows the first setting in which both the main solution and the concentrate are dispensed from the tube. In this setting, both of the main solution metering slots 62a and 62b are open together with the single concentrate metering slot 60a. If the adjustable overcap is rotated downwardly to the setting shown in FIG. 12, it can be seen that in addition to the previously mentioned open concentrate metering slot 60a, metering slot 60b is also open. Thus, it can be seen that at the setting shown in FIG. 12, the volume of the dispensed concentrate has been increased with respect to the volume of the dispensed main solution.

It will be appreciated from the preceding description of the operation of the plural chambered dispensing tube 10 that the combination of the metering slots and adjustable overcap selectively controls the discharge or fluid coupling of the concentrate and main solution fluid paths to the chambers 16 and 26. Thus, it is possible to fluidly couple the dispensing tube outlet to one or both or neither of the chambers merely by rotating the adjustable overcap 22 to the appropriate setting of Main Solution and Concentrate or Closed. Additionally, the amount or degree of fluid coupling can be varied by selection of the appropriate combination of concentrate and main solution metering slots.

Although the main solution metering slots 62 have been shown in the drawings on the outer surface of the outsert nozzle 54, other arrangements can be employed. For example, the main solution metering slots 62 can be placed on the inner surface of the adjustable overcap and operate in conjunction with a solid outer surface on the outsert nozzle 54.

It has already been mentioned that in the preferred embodiment of the present invention, the insert walls 14 are relatively rigid in order to prevent accidental discharge of the concentrate and deformation of the foam plastic interface 18. Given the relatively rigid configuration of the insert walls 14a or alternatively the surrounding portion of the tube walls 12, it can be seen that when the concentrate in chamber 16 has been fully dispensed so that the movable interface 18 is in its full downward position as viewed in the drawings, the main solution could occupy the volume formerly occupied by the insert 18. With typical fill ratios of 4:1 main solution to concentrate, up to 20 percent of the main solution could be hungup or trapped within the cylindrical chamber of the insert 14.

The problem of main solution hangup can be substantially eliminated if the flexible tube walls 12 have a memory so that they will return to their unsqueezed shape after the squeezing pressure is released. In this case, air will be sucked back through the main solution fluid path into the second chamber 26. With air present within the tube, pressure still can be exerted upon the main solution even when the level of the main solution is depleted below the upper end of the insert cylinder 14 (as viewed in the drawings). If the insert 14 is provided with a plurality of circumferentially spaced main solution slots 82 as shown in FIG. 1, the main solution can be forced outwardly through the slots 82 and then downwardly through the normal main solution channels 38. This configuration minimizes the amount of main solution trapped within the insert and allows the user to discharge substantially all of the main solution. The depth of the main solution slots 82 is less than the axial length or height of the cylindrical interface 18 in order to provide a sufficient seal between the lateral surface 18a of the interface and inner wall surface 14a of the insert.

It will be appreciated that in the case of self-collapsing tubes which do not have a memory, such as, metal tubes, no air is sucked back through the main solution fluid path. Accordingly, a greater amount of main solution remains trapped within the insert cylinder 14.

Looking at FIG. 1, it can be seen that the generally cylindrical interface 18 has a substantial axial length or height. In order to achieve maximum volumetric replacement of the concentrate within chamber 16, the length of the cylindrical interface 18 is made substantially equal to the height or fill level of the concentrate within chamber 16. Thus, when the concentrate is fully depleted, the cylindrical interface 18 replaces the same volume as the concentrate.

Having described in detail a preferred embodiment of the plural chambered dispensing tube of the present invention, it will be apparent to those skilled in the art that various modifications and alternative constructions can be made without departing from the scope of the invention. For example, the first chamber 16 and the interface 18 have been depicted in the drawings as having a circular cylindrical configuration. However, other cylindrical shapes, such as, elliptical, rectilinear, etc., can be used for the first chamber 16 together with a correspondingly shaped interface 18.

The interface itself has been described as comprising a low density polyethylene foam which provides the desired degree of compressibility and resiliency. It will be appreciated that the interface can have a relatively rigid core portion with a perimeter section of a compressible and resilient material. The compressibility and resiliency of the perimeter section should be sufficient to compensate for the molding tolerances of the insert chamber 16.

Claims

What I claim and desire to secure by Letters Patent of the United States is:

1. A plural chambered, hand squeezable, dispensing tube suitable to be produced in commercial quantities and functioning effectively under tolerances permissible in such commercial production, said dispensing tube comprising:

1. an elongated, flexible walled, squeeze tube means defining first and second chambers for storing first and second fluids, respectively, said first chamber having a generally cylindrical configuration;

2. first and second fluids stored in said first and second chambers, respectively;

3. a generally circular cylindrical first and second fluid interface of polymeric foam positioned within and movable along the axis of said first chamber, said interface having an outside diameter greater than the maximum diameter of the generally circular cylindrical first chamber and being compressed when positioned within said first chamber to form a sliding seal of zero clearance with the walls of the first chamber which automatically assumes the cross-sectional size and shape of the generally cylindrical first chamber to maintain said zero clearance as the interface moves along the axis thereof;

4. selectively operable outlet means for fluidly coupling to one, both or neither of said first and second chambers; and,

5. selectively operable means for varying the ratio of the fluid couplings between said outlet means and said first and second chambers whereby the ratios of the dispensed first and second fluids can be varied.

2. A plural chambered, hand squeezable, dispensing tube suitable to be produced in commercial quantities and functioning effectively under tolerances permissible in such commercial production, said dispensing tube comprising:

1. an elongated, flexible walled, squeeze tube means defining first and second chambers for storing first and second fluids, respectively, said first chamber having a generally circular cylindrical configuration;

2. first and second fluids stored in said first and second chambers, respectively;

3. a generally circular cylindrical first and second fluid interface of low density polyethylene foam positioned within and movable along the axis of said first chamber, said interface having an outside diameter greater than the maximum diameter of the generally circular cylindrical first chamber and being compressed when positioned within said first chamber to form a sliding seal of zero clearance with the walls of the first chamber which automatically assumes the cross-sectional size and shape of the generally cylindrical first chamber to maintain said zero clearance as the interface moves along the axis thereof;

4. selectively operable outlet means for fluidly coupling to one, both or neither of said first and second chambers; and,

5. selectively operable means for varying the ratio of the fluid couplings between said outlet means and said first and second chambers whereby the ratios of the dispensed first and second fluids can be varied.

3. The apparatus of claim 2 wherein said first and second fluid interface is a closed cell, low density polyethylene foam and wherein the sliding seal formed by said first and second interface comprises a plurality of said foam cells that are in open, fluid communication with the walls of the first chamber and are not in fluid communication with each other.