Compartment Bag Assembly For Dispensing Containers

Abstract

A product dispensing container of the type including a collapsible product containing a bag assembly which is disposed within a rigid container and defines a chamber therein. The chamber is filled with a propellant. A valve dispensing means communicates with the bag assembly for discharging the product therefrom under the force of the propellant. The product containing bag assembly includes a compartment bag constructed so as to be only axially collapsible when subjected to the radial and axial forces of the propellant. The bag assembly further includes a barrier bag or sheath which encloses the compartment bag. The barrier bag is made from an impermeable film material and is flexible so as not to influence the axial collapse of the compartment bag.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to product dispensing containers which include a product containing compartment and a propellant compartment. The compartments are generally separated by a common wall of the product containing compartment. In some instances, the common wall of such dispensing containers is defined by a collapsible bag positioned internally of the container body and secured to a top closure of the latter. The top closure generally includes a manually operable valve-actuated dispensing mechanism for dispensing a product packaged within the bag under the influence of a pressurized propellant housed in the propellant chamber between the bag and the container body.

One form of collapsible bag includes fold bands axially spaced from each other to provide a pleat-like wall for rigidifying the bag and maintaining its shape against the forces acting radially and axially thereon so that the bag collapses uniformly both radially and axially without the panelling or indiscriminate folding. The elimination of the indiscriminate folding prevents blockage to the dispensing valve.

The collapsible bags are made from a plastic material such as polyethylene or the like and formed by molding such as blow molding. However, unless special precautions are taken these bags have problems with gas permeation of the propellant into the bag which may result in an undesirable mixture of the bag contents and the propellant. For this reason, the material from which the bag is made has been restricted to plastic compositions having special formulations which tends to minimize the permeation. These special formations have increased the the cost of the bag while not always providing the necessary impermeability.

By the present invention, it is proposed to provide a compartment bag arrangement which overcomes the permeability of propellant gas into the product containing or compartment bag.

This is accomplished by a compartment bag arrangement comprising a collapsible bag having a generally pleated structure to resist the radial and axial pressure forces exerted by the propellant so as to eliminate panelling or indiscriminate folding in a manner causing blockage of the product. The bag is retained in a container body clinching the open end of the bag between the rolled rim at the upper open end of the container body and the dome in which the dispensing valve is mounted.

Disposed about the pleated compartment bag is a barrier sheath or bag which is also clinched between the rolled edge and the dome. The barrier sheath is of a laminated flexible structure of which of least one of the layers is flexible non-permeable material.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a longitudinal cross sectional view of the dispensing container with parts broken away for clarity, and showing a bag arrangement embodying the structure of the prevent invention.

FIG. 2 is a longitudinal section view of the dispensing container of FIG. 1 with parts broken away for clarity and illustrating a partially collapsed position of the bag arrangement.

FIG. 3 is a greatly enlarged fragmentary sectional view of the encircled portion of FIG. 1 and showing in particular the manner in which the bag arrangement is secured to the container.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1 and 2, there is shown a product dispensing container 10 of the general type with which the product dispensing bag assembly 11 of the present invention is adapted to be used. The container 10 comprises generally a container body 12 in which a product dispensing bag assembly 11 carries the product to be dispensed, and a propellant chamber 13 defined between the exterior of the bag assembly 11 and the inside wall of the container body 12.

The container body 12 includes axially opposed top and bottom closures 14 and 16, respectively. The top closure 14 comprises a dome 17 formed with an axial opening 18 bounded by a rolled rim 19. The product is filled through the opening 20 into the product dispensing bag assembly 11. After the bag assembly 11 is filled, a cup 21 supporting a dispensing valve 22 which may be of well-known construction is attached to the rim by clinching. The bottom closure 16 is formed with an opening 23 in which a grommet or charging valve 24 is seated. The propellant is charged into the propellant chamber 13 through the charging valve in any one of the well-known procedures.

The compartment bag assembly 11 includes a collapsible product bag 26 and an outer sheath or protective bag 27. The collapsible product bag 26 is formed from a plastic material such as polyethylene and preferably by blow molding. The bag 26 is sufficiently thick so as to be capable of retaining its configuration under normal atmospheric pressure and under the propellant pressure forces acting thereon when the bag is completely filled with a product. The collapsible bag 26 includes a cylindrical side wall 28, a bottom wall or base 29 located in vertically spaced relationship with respect to an upper domed end portion 31. The upper domed end portion 31 of the bag is open and is fastened to the rim as more fully to be explained hereinafter.

To regulate the collapsing of the product bag 26 in a manner to eliminate indiscriminate panelling of the cylindrical wall 28 and the bottom wall 29, there is provided a plurality of lengthwise spaced fold sections 32. As shown, the fold sections 32 are spaced lengthwise of the cylindrical wall 28 so as to define therebetween a plurality of annular side bands 33. The fold sections 32 each comprise a pair of annular panels 34 which are arranged in V-shaped configuration and integrally joined along a common inner fold line defining the vortex of the V. The outer ends of the annular panels 34--34 are integrally joined along fold lines to the upper and lower edges of the adjacent annular bands 33. Preferably the fold panels 34--34 are inclined inwardly at about an angle of 60.degree. relative to the annular bands 33. For a more detailed description of the structure of the product bag 26, reference is made to U.S. Pat. No. 3,467,283.

The outer barrier sheath or protective bag 27 is of generally tubular construction and includes a side wall 36 and a bottom wall 37 and an open upper end 38. The sheath 27 is sized to loosely encompass the compartment bag 26 and is made from a non-permeable film material to provide a gas barrier between the propellant and the interior of the compartment bag 26. In the embodiment shown, the impermeable film is of a laminate or co-extruded structure of polyethylene. An impervious plastic material such as Saran polyethylene and a metal foil laminate structure of polypropylene and polyester plastic may also be used to form a protective barrier. The wall of the sheath 27 is of minimum thickness so that it collapses indiscriminately and in this way does not interfere with the controlled collapse of the compartment or product bag 26.

The compartment bag 26 is inserted into the straight sided and flexible protective sheath 27 and the upper end thereof is fastened to the collapsible compartment bag 26. This may be accomplished by inserting the loosely assembled barrier bag 27 and compartment bag 26 through the opening 18 in the dome 17. A heat flanging tool is then inserted into the bag opening and into engagement with the upper ends of the sheath 27 and the compartment bag 26 so that they are simultaneously sealed to each other and over the curl 19. Thereafter, the cup 21 is seated in the opening and clinched over the prior heat sealed area of the compartment bag 26 and the sheath 27 and the curl 19. Alternatively, the compartment bag 26 may be loosely inserted into the sheath 27 prior to insertion of the latter into the can body 12. The sheath 27 may then be heat sealed to the internal compartment bag 26 at the dome area which normally overlies the curl. The assembled sheath 27 and the compartment bag 26 may then be inserted into the can body in the more or less conventional manner with the sealed area on the curl 19. The cup 17 is then clinched over the curl 19 thereby clamping the bag assembly 11 therebetween.

In operation when the valve 22 is released so that the product is dispensed therethrough, the pressure forces of the propellant within the propellant chamber 13 are operative to react on bag assembly 11 to force the compartment bag 26 axially upward. As the bag 26 moves axially upward, the annular panels 34--34 each fold about the inner fold line and the outer fold lines. As the panels 34--34 fold during dispensing of the product, the included angle therebetween gradually decreases until the panels lie in superimposed horizontal relationship. The panels 34--34 thus form in the nature of rigidifying bands which resist the radial forces acting on the side wall 29 to prevent radial collapse of the bands 33 inwardly. At the same time, the panels 34--34 also exert an axial force tending to maintain the base 24 substantially normal to the side wall of the container body 12 whereby the bag collapses uniformly along its length without tilting relative to the longitudinal axis. In this manner the contraction of the product dispensing bag 26 is regulated and controlled. At the same time, the barrier bag or sheath 27, which is flexible, is indiscriminately forced against the sides of the compartment bag 26. The sheath 27 does not, because of its flexibility, influences the discharge of the product from the bag 26.

As the product is further dispensed through the valve 22 after the panels 34--34 are folded superimposed relationship, the side bands 33 collapse irregularly under the force exerted by the propellant. As shown in FIG. 2, the side bands collapse by folding so that substantially areas of the outer surfaces thereof are in face to face contact. In this connection, it should be mentioned that the width of the side bands 33 is preferable such that in the collapsed condition, no portion thereof is disposed outboard of the vortex of the collapsed panels 34--34 thereby to provide an uninterrupted center passage for the flow of the product to the dispensing valve 22. Moreover, the thickness of the collapsed side bands 33 is substantially uniform about the circumference so that a minimum of axial tilting occurs whereby the base 29 remains substantially parallel to the bottom closure 14 when the compartment bag 26 approaches the dome 17. The base 29 may bulge upwardly to force further product through the valve 22. During the entire collapse of the compartment bag 26, the barrier bag 27 is held by the pressure forces in indiscriminate engagement with the bag 26. The barrier bag 27 is of thin wall construction in the nature of a film and provides a barrier layer which serves to prevent permeation and mixture of the propellant with the contents of the compartment bag 26.

Claims

What is claimed is:

1. In a product dispensing container having a pressurized container body including a base and a top closure at axially opposite ends of said body, a dispensing valve carried by said top closure, and a collapsible product dispensing bag assembly disposed in the interior of said container body and defining with said container body a propellant chamber charged with a pressurized propellant, said bag assembly comprising a product-containing compartment bag having a plurality of lengthwise spaced fold sections so as to be axially collapsible, and a non-dispensing closed gas filled tubular sheath attached to and enclosing said compartment bag for transmitting pressure from the propellant chambers to the compartment bag, said tubular sheath being made from an impermeable film to provide a barrier between said compartment bag and said propellant chamber and maintaining the initial quantity of gas therein during the entire operating period, to maximize dispensing of the product contained in said bag assembly.

2. The invention as defined in claim 1 wherein said tubular sheath is attached to the upper end of said compartment bag.

3. The invention as defined in claim 2 wherein said tubular sheath is attached to said compartment bag by a heat seal.

4. The invention as defined in claim 3 wherein said compartment bag is made from plastic, and wherein said tubular sheath is made from a laminate having at least one layer of plastic.

5. The invention as defined in claim 4 wherein said laminate includes a metal foil layer.