Apparatus and method for sealing a dispensing valve to a bag

Abstract

Disclosed herein is a dispensing valve and bag combination comprising, a valve body, a receptacle body and a seal. The valve body has an appendage extending therefrom and a sealing seat on the appendage. The receptacle body has a bore that is receptive of the appendage of the valve body. The receptacle body is sealable to the appendage when the seal is positioned at the sealing seat and the appendage is inserted into the bore. Further disclosed herein is a method of sealing a dispensing valve to a bag comprising, diametrically sealing a valve body to a receptacle body with a seal positioned between an appendage of the valve body and a bore of the receptacle body.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to provisional application 60/687,963 filed Jun. 7, 2005, the entire contents of which are incorporated herein by reference.

BACKGROUND

This disclosure relates to improvements in a dispenser for a dispensable fluid. One example of such a dispenser is for a hydrocarbon fuel, which includes an outer canister containing a typically organic pressurized propellant, an inner bag containing the dispensable fluid, and a normally closed valve enabling the dispensable fluid to be controllably dispensed from the inner bag.

It is known in the art to use a dispenser of the type noted above to dispense a hydrocarbon fuel to a combustion gas-powered fastener-setting tool. Typically, the inner bag of such a dispenser is made from a flexible, laminated, multi-layer sheet. The sheet may have an outermost layer of nylon film, an intermediate layer of aluminum foil, and an innermost layer of polyethylene film with suitable bonding layers between the aluminum and other layers. The polyethylene layer can be heat-sealed to itself as well as heat sealed to an injection molded receptacle body. Typically the receptacle body is mechanically sealed to a valve that interfaces with the outer canister as described below.

Referring to FIGS. 1 and 2, cross sectional views of a prior art valve and bag assembly are depicted. A tubular appendage 27 of a valve body 17 is engaged in a through hole 30 of a receptacle body 28 disposed on a bag 25. The appendage 27 extends axially from a radial surface 31 of the valve body 17. A retention barb 29 on an end of the appendage 27 has a radial lip 32 extending therefrom for engaging with an undercut diameter 23 of the receptacle body 28 and retaining the valve body 17 to the receptacle body 28. Sealing of the valve body 17 to the receptacle body 28 is achieved by axial compression of an elastomeric flat ring 18 between the surface 31 and a radially extending surface 33 of the receptacle body 28. In order to assure adequate compression of the flat ring 18 the dimensions of the components that control the amount of flat ring 18 compression must be accurately maintained. Specifically, the axial distance from the surface 31 of the valve body 17 to the lip 32 of the barb 29 must be matched to the axial length of the undercut diameter 23 and the axial length of the flat ring 18. Additional localized compression of an annular area of the flat ring 18 is be created by the addition of a raised annular bump 24 in the surface 33 of the receptacle body 28.

Compression of the flat ring 18 is critical to the integrity of the seal between the valve body 17 and the receptacle body 28. The tight tolerances required of the dimensions to maintain the necessary compression levels during the life of the product, including after component swell, is therefore critical as well. Manufacturing and maintaining the tight tolerances required may be difficult and expensive.

The pressure differential across the bag 25 is essential for the operation of the dispenser. The pressure differentional may dissipate in one of two ways, either by, leakage by the seal (created by the flat ring 18 described above), or by permeation of the propellant through the components that form the seals. The elastomeric materials used for the flat ring 18 are substantially impermeable to the propellants that are typically used, and are therefore not of concern regarding this issue. The choice of materials for the receptacle body 28, however, is limited due to the requirement that it be weldable to a layer of the bag. As such, materials used for the receptacle body 28 are typically permeable to the propellant.

Accordingly, there is a need in the art for improvements in the sealing of bags to valve bodies that do not rely on tight tolerances of several components. There is an additional need to minimize or eliminate exposure of permeable materials to a propellant pressure differential.

SUMMARY OF THE INVENTION

Disclosed herein is a device that relates to a dispensing valve and bag combination comprising, a valve body, a receptacle body and a seal. The valve body has an appendage extending therefrom and a sealing seat on the appendage. The receptacle body has a bore that is receptive of the appendage of the valve body. The receptacle body is sealable to the appendage when the seal is positioned at the sealing seat and the appendage is inserted into the bore.

Further disclosed herein is a method that relates to sealing a dispensing valve to a bag comprising, diametrically sealing a valve body to a receptacle body with a seal positioned between an appendage of the valve body and a bore of the receptacle body.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts a cross sectional view of a prior art valve assembly;

FIG. 2 depicts a magnification of the cross sectional view of FIG. 1;

FIG. 3 depicts a cross sectional view of an embodiment disclosed herein; and

FIG. 4 depicts a magnification of the cross sectional view of FIG. 3.

DETAILED DESCRIPTION

A description of exemplary embodiments of the invention will now be had, by way of exemplification and not limitation, with reference to the Figures.

Referring to FIGS. 3 and 4, a dispensing valve 38 and a bag assembly 39 are shown sealed to one another. A valve body 50 of the dispensing valve 38 has an appendage 54 extending axially from a surface 60 of the valve body 38. A barb 58 on an end of the appendage 54 has a lip 62 extending radially therefrom. Approximately midway between the surface 60 and the lip 62, along the appendage 54, is an appendage groove 56 that is annular in structure and sized to receive a seal 52, disclosed herein as an o-ring.

A receptacle body 40 attached to a bag 25 has a diameter through bore 42 therethrough sized to receive the appendage 54. The diameter of the through bore 42 is slightly smaller than the diameter of the lip 62 of the barb 58 thereby creating an interference of the lip 62 with the bore 42. During installation of the appendage 54 into the receptacle body 40 this interference may be forcibly overcome, however, the interference is sufficient to prevent extraction of the appendage 54 from the receptacle body 40 during normal use of the apparatus. Thus, the barb 58 serves to retain the receptacle body 40 to the valve body 50. The receptacle body 40 has a seal recess 44 disposed along the through bore 42 to receive the seal 52. As illustrated, the recess is approximately midway between surfaces 46 and 48 on opposing ends of the receptacle body 40. Thus, the appendage groove 56 and the seal recess 44 are positioned in axial alignment with one another in response to the lip 62 of the barb 58 being in axial alignment with the surface 46 of the receptacle body 40.

In the embodiment of the present invention described above the seal 52 is compressed radially between an outer diameter 63 of the appendage groove 56 and an inner diameter 65 of the seal recess 44 thereby sealing the valve body 50 to the receptacle body 40. Thus, only two dimensions are required to maintain the desired compression of the seal 52, namely, the outer diameter 63 and the inner diameter 65.

One of the benefits of the disclosed embodiments is that dimensions may be held to looser tolerances than that required in the prior art. These looser tolerances may translate into lower manufacturing costs. Specific dimensions that may have looser tolerances are, the length between the surface 60 and the lip 62 of the appendage 54, and the length of the receptacle body 40 between surfaces 46 and 48, for example. In the prior art, such dimension must be very accurately controlled whereas in the present disclosure these dimensions may tolerate somewhat greater lengthwise variations without detrimental effect with respect to pressure sealing.

It should be noted that the groove 56 in the appendage 54 and the seal recess 44 in the receptacle body 28 are optional features. In embodiments of the invention that do not incorporate the groove 56 or the seal recess 44, the seal 52 would seal directly to a seal seat portion of the appendage 54 and to the bore 30 of the receptacle body 28.

Since, as was noted above, the receptacle body 40 is permeable to many propellant chemical species intended to remain outside of the bag 25, a tolerance take up device 64 is placed in a notch 66 of the valve body 50. The notch 66 is positioned such that it locates the tolerance take up device 64 against the surface 48 of the receptacle body 40 in radial alignment with an outer circumferential surface 67 of the receptacle body 40. This location of the tolerance take up device 64 occludes the propellant from reaching the surface 48 and thereby prevents the propellant from permeating through the receptacle body 40. The tolerance take up device 64 is biased by a pressure gradient from the outside of the bag 25 toward the inside of the bag 25, which forces the tolerance take up device 64 into contact with the surface 48 of the receptacle body 40. This pressure on the tolerance take up device 64 is sufficient to prevent any significant infiltration of propellant from the outside of the bag 25 to the inside of the bag 25. The balance of the components illustrated in FIG. 3 are conventional in the art and are identified hereinbelow solely for purposes of clarity.

A compression spring 68 is compressed between the valve body 50 and a valve stem 70 to hold the valve stem 70 in a normally closed position against an internal gasket 72. The valve is disposed within an outer canister 74 which further comprises a mounting cap 76 and an external gasket 78 disposed between the outer canister 74 and the mounting cap 76.

While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.

Claims

1. A dispensing valve and bag combination, comprising:

a valve body;

an appendage extending from the valve body;

an appendage seal seat encircling the appendage and receptive of a seal;

a receptacle body having a bore receptive to the appendage of the valve body; and

a seal positioned at the appendage seal seat and sealable against the bore when the appendage is inserted in the bore.

2. The dispensing valve and bag combination of claim 1, wherein:

the seal is an o-ring.

3. The dispensing valve and bag combination of claim 1, wherein:

the seal is made with a low permeability material.

4. The dispensing valve and bag combination of claim 1, wherein:

the seal is made of an elastomeric material.

5. The dispensing valve and bag combination of claim 1, wherein:

the valve body is injection molded with a low permeability resin.

6. The dispensing valve and bag combination of claim 1, further comprising:

a bag wherein the receptacle body is heat sealed thereto.

7. The dispensing valve and bag combination of claim 1, further comprising:

a circumferential notch in the valve body at a radial location substantially equal to an outer circumferential surface of the receptacle body; and

a tolerance take up device disposed at the notch between the valve body and the receptacle body.

8. The dispensing valve and bag combination of claim 7, wherein:

the tolerance take up device has a rectangular cross section.

9. The dispensing valve and bag combination of claim 7, wherein:

the tolerance take up device is made with a low permeability material.

10. The dispensing valve and bag combination of claim 7, wherein:

the tolerance take up device is made of an elastomeric material.

11. The dispensing valve and bag combination of claim 1, further comprising:

a groove annularly encircling the appendage wherein the seal seat is disposed within the groove.

12. The dispensing valve and bag combination of claim 1, further comprising:

a seal recess within the bore of the receptacle body.

13. The dispensing valve and bag combination of claim 1, further comprising:

a barb disposed at the appendage spaced from the valve body and engagable with the bore of the receptacle body.

14. A method of sealing a dispensing valve to a bag, comprising:

diametrically sealing a valve body to a receptacle body with a seal positioned between an appendage of the valve body and a bore of the receptacle body.

15. The method of claim 14, further comprising:

occluding propellant from permeating through the receptacle body with a tolerance take up device disposed against a surface of the receptacle body in a notch of the valve body.

16. The method of claim 15, further comprising:

biasing the tolerance take up device against the receptacle body with a pressure gradient that exists from the outside of the bag toward the inside of the bag.

17. The method of claim 14, further comprising:

retaining the receptacle body to the valve body with a barb on the appendage of the valve body that has a greater radial extension than the through bore of the receptacle body.