US20120138639A1

US20120138639A1 - Enhanced Valve Sealing In Pressurized Dispensing Container

Info

Publication number: US20120138639A1
Application number: US12/960,773
Authority: US
Inventors: Christian T. Scheindel
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-12-06
Filing date: 2010-12-06
Publication date: 2012-06-07

Abstract

An improved valve for a pressurized dispensing container has a long sealed shelf life. This is obtained by having the valve stem button drive a tunnel into the grommet which provides both enhanced sealing between the button sidewall and grommet as well as the pinching of the grommet between the button and the valve mounting cup to prevent grommet material creep. A laterally extending annular plate from the bottom of the button facilitates dispensing in a tilt valve fashion. The lower portion of the stem has an interference fit with the grommet. The plate is spaced from the bottom surface of the grommet sufficiently so that the bending of the grommet base that occurs under pressure does not result in contact between the grommet and the tilt plate.

Description

BACKGROUND OF THE INVENTION

This invention relates to ensuring that a valve is sealed in a pressurized dispensing container when the valve is in its sealed state.
A problem in obtaining a fully effective seal in the sealed state of the valve arises in connection with dispensing products that have grit or particles. Peanut butter and Fixodent are such products.
It has been found that a number of products cannot be dispensed from these pressurized containers because in the sealed (or closed) state there is some leakage of product. One result is a loss of shelf life.
For example, in peanut butter the oil separates out from the rest of the product and, when dispensed, the oil comes out first, separate from the rest of the product. This is unsatisfactory to the end user.
The sealing elements in the valve are the button on the base of the valve stem and the resilient grommet that surrounds the valve stem. It is believed that what happens is that particles lodge between the button and the grommet providing enough communication across the seal to create some pressure differential across the product. In peanut butter, this causes oil separation when the container is not being used. Regardless of the exact mechanism, this deterioration of product has been observed.
There are two related conditions which any design must address.
The first is to provide an initial effective sealing in a sealed state.
The second is to maintain that effective sealing over a substantial period of time. This is shelf-life. For many products, shelf-life has to extend over many months and even at times years.
It has been found that product containing grit or particles tends to defeat effective sealing. It is believed that these particles cause enough of a break or separation between sealing surfaces so that a pressure gradient is established across the sealing surface. This pressure gradient at its low end is the ambient pressure of the valve stem passageway and at its high end the pressure of the product in the container. It is believed that this gradient results in a separation of product components. In the case of peanut butter, the separation is between the oil and the denser product. When the separation occurs, the result is that when the user actuates the valve, the product dispensed is not well mixed and initially the oil component is dispensed by itself. This is completely unsatisfactory for the user.
This separation problem and other degradation that occurs because of inadequate sealing becomes more severe over time and results in a limited shelf-life.
Indeed, a product that might initially be adequately sealed, will respond to the pressure differential to deteriorate over time. This shelf-life provides an unsatisfactory commercial product.
Accordingly, it is a major object of this invention to provide a valve structure that assures a complete and effective seal when the valve is in its sealed or closed state. This means there is no communication across the seal and that the product is under constant pressure while it is on the shelf.
It is a related purpose of this invention to achieve the main object in an inexpensive fashion with a design which does not compromise the dispensing operation of the container.
It is a further related purpose of this invention to achieve the above objects in a design which involves use of known types of valve components so as to minimize the cost of adopting the invention.

BRIEF DESCRIPTION

In brief, a device of this invention provides a stem button to grommet seal in which the stem button compresses an annular segment of the grommet. The compressed segment is an annular zone around the grommet central opening. The button by forcing its way into the grommet displaces and compresses grommet material to create a tunnel into which the button fits and thus provide a seal between button sidewall and grommet tunnel wall.
The creation of the tunnel also provides a highly compressed grommet zone between the button and the mounting cup to provide a tight grip on the grommet between button and mounting cup. The seal provided is not compromised by the grit or particles in the product.
The grommet base is shorter than traditional grommets to assure a tight grip on the grommet between button and mounting cup that minimizes grommet material creep. The button has a smaller diameter than most buttons to assure that the amount of grommet material displaced by the button forming a tunnel is small enough to permit the compression and displacement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of one embodiment of the valve 10 of this invention in an assembled state prior to pressurizing. FIG. 1 shows the arrangement between the annular valve stem 12 (shown in relief) and the annular grommet 14 (shown in section). The stem button 16 is at the lower end of the stem. The mounting cup 18 is in section.

FIG. 2 is a side view, in partial section similar to that of FIG. 1, of the valve 10 in its sealed state. FIG. 2 shows the proximity of the button 16 to the mounting cup 18 in the sealed state and also shows the tunnel 22 that the button forms in the grommet.

FIG. 3 is a side view, with the grommet 14 partially cut away, of the valve 10 in its dispensing state when tilted to dispense product.

FIG. 4 is a side view, in partial section (similar to that shown in FIG. 1) of the valve 10 in its dispensing state when moved vertically to dispense product.

FIG. 5 is a sectional view through the annular grommet 14 in its relaxed (unassembled) state.

TERMS

The following terms are used herein with the meaning indicated below.
Up and Down, Lower and Upper: These terms refer to the relative position of elements on the FIGs. These terms have the obvious meaning when the container and valve is in an upright position on the shelf. When dispensing, the container and valve are usually tilted and even turned upside down. However, for convenience of reference, these terms are used to refer to relationships along the axis of the valve when the valve is in an upright position as shown in the FIGs.
Mils is the abbreviation for thousandths of an inch.
ID and OD refer, respectively, to inner diameter and outer diameter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The FIGs. illustrate a single embodiment. A pressurized dispensing container (not shown) has a top center opening through which the valve 10 extends. The stem 12 of the valve is partially threaded so as to engage the threaded inner surface of a nozzle (not shown).
An annular resilient grommet 14 extends around the lower portion of the valve stem 12. The grommet is held between the button 16 at the base of the valve stem 12 and a downwardly facing ledge 20 on the valve stem 12. In the sealed state, the inner surface of the grommet 14 seals the valve stem openings 28. The lower portion of the stem 12 has an interference relation to the inner surface of the grommet 14. This contributes to effective sealing in the sealed state.
The mounting cup 18 holds the valve on the container.
Most important, the button 16, under pressure from the pressurized product, compresses an annular segment of the grommet 14 thereby forcing its way into the grommet 14 by creating a tunnel 22. This provides a forceful sealing engagement between grommet 14 and button 16. At the end of this tunnel 22, the button 16 creates an engagement of the grommet 14 so that the grommet is tightly squeezed between button 16 and mounting cup 18.
It is believed that the close spacing between button 16 and cup 18 in the sealed state provides a grip on the grommet 14 which assures that the sealing effect of the grommet is not compromised by grommet creep or other grommet rearrangement that would diminish shelf life. To provide this close spacing, the grommet base 23 is shallow compared to prior art grommets so that the button 16 will be close to the cup 18 in the sealed state.
In the embodiment shown, the stabilizing pinch is provided by a geometry wherein (a) the upper surface of the button 16 is higher than the lower surface 24 of the cup 18 and (b) the outer diameter of the button is less than the inner diameter of the cup.
A geometric relationship that brings about the close relation of button 16 and cup 18 is that the tunnel 22 created by the button 16 extends up to a point past the lower surface 24 of the cup 18.
When a nozzle (not shown) forces the valve stem 12 to move, by either tilting or by vertical movement, one or more of the valve stem openings 28 are exposed to the product held under pressure within the interior of the container. The product under pressure will then be forced through one or more of the openings 28 to a central axial passageway 30 of the valve stem to exit from an opening at the top of the valve stem into the nozzle (not shown) to be dispensed at the upper end of the nozzle.
The operation of valves in pressurized dispensing containers is well known and is described in greater detail in U.S. Pat. No. 7,222,758; U.S. Pat. No. 6,874,663 and U.S. Pat. No. 5,785,301. The teachings of these patents is incorporated in here by reference. In the closed state, the prior art devices do not create the tunnel 22 and do not bring the button 16 close to the mounting cup 18.
The pressure of the product within the container on the button 16 maintains the button in its closed state at the end of the tunnel 22 as well as forcing the button to create the tunnel when the valve is released after being held open. A restoring force exerted by engagement of the boot 30 of the grommet 14 against the ledge 20 on the stem 12 serves to bring the button up against the base 36 of the grommet when the manual pressure that holds the valve open is removed. Then the pressure from the product takes over to force the button 16 to compress the grommet annulus and create the tunnel 22.
A plate 32 at the base of the button 18 provides a fulcrum that assists in tilting the valve 10 into an dispensing state when the valve is used as a tilt valve. A hand operated lever (not shown) provides an assist when the valve is used as a vertically or axially moved fashion to dispense product. U.S. Pat. No. 6,340,103 provides a description of such a lever.
It is important that the button 16 be thick enough that the tilt plate 32 is spaced from the lower surface 36 of the grommet 14 in the sealed state. This geometric arrangement is important to assure that the outboard parts of the grommet base 36 which deflect downward in the sealed state do not engage the tilt plate 32 in the sealing state (see FIG. 2).
The grommet must be soft enough (a durometer of Shore D 55 in one tested sample) permits the button 16 under pressure to compress the grommet material enough to create the tunnel 22. The button diameter has to be small enough so that the annulus of grommet can be compressed. In the sample with the 45 durometer grommet, a button having a 360 mil diameter is employed with a grommet having a 256 mil inner diameter at the bottom portion of the stem and grommet.
There is an interference fit relationship between the stem 12 wall at the zone of the stem openings 28 and the adjacent grommet 14 wall. FIG. 5 shows the grommet in its unassembled and therefore relaxed state. A bump 34 on the inner wall of the grommet provides a slightly greater interference between grommet and stem to assure sealing.
Applicant believes that the above analysis is the explanation of what occurs in the use of prior art designs. But there may well be a somewhat different explanation or, more likely, a supplementary explanation.
Tests have been made with peanut butter using the valve of this invention and the results have been satisfactory in that the entire product, oil and particles, stayed sealed into the container without leakage when the valve was in its sealed state.
In one embodiment, the following approximate dimensions and parameters are employed.
Button 16 OD: 364 mils.
Button 16 height or thickness: 140 mils.
Length of tunnel 22: 130 mils.
Stem 12 wall OD in the zone of the boot 31: 256 mils.
Stem 12 wall OD at the zone of the stem openings 18: 276 mils.
Grommet 14 ID in a relaxed state at the zone of the stem openings: 254 mils.
Grommet ID in a relaxed state at the bump 34: 236 mils.
Grommet 14 base thickness: 740 mils.
Tilt plate 32 diameter: 700 mils.
Tilt plate 32 thickness: 60 mils.
Stem wall openings 28: 60 mils by 80 mils.
Grommet 14 hardness: Shore D 55.
Mounting cup 18 opening 406 mils.
The valve structure described can be used as a tilt valve or as a vertical valve. The tilt plate 32 makes it feasible to open the valve when used as a tilt valve. The tilt plate 32 is useful in both tilt and vertical uses to assure against a blow out of product. Blow out might occur if the pressure on the button forces it through the valve stem passageway. Proper attention to tolerances should assure that this will not happen. But the tilt plate provides back up assurance.
A valve stem with four openings 28 all of which are exposed to product makes it easier to dispense highly viscous product. In the case of the vertical valve used to dispense highly viscous products, it may be useful to have a spring return assist. It would also be useful to have an actuating lever to facilitate opening the valve against the higher dispensing pressures required for the more viscous products.
While the foregoing description and drawings represent the presently preferred embodiments of the invention, it should be understood that those skilled in the art will be able to make changes and modifications to those embodiments without departing from the teachings of the invention and the scope of the claims.

Claims

1. In a valve for use with a pressurized container for dispensing a product, the valve having a stem with a button, an annular mounting cup and an annular sealing grommet made of a resilient material, the stem extending through a central opening of the grommet, the valve having a sealed state and a dispensing state, the improvement to provide enhanced shelf-life comprising:

in said sealed state, said button of said stem compressing an annular segment of said grommet at said opening in said grommet to create a tunnel for said button within said grommet, and

in said sealed state, said button providing a seal between the surface of said button and the tunnel surface of the compressed grommet, said button also providing a stabilizing pinch of said grommet between said button and said mounting cup.

2. The improvement of claim 1 wherein the lower portion of said stem has an interference fit relation with the adjacent portion of said grommet.

3. The improvement of claim 1 further comprising: a plate on the base of said button extending outboard of said button to provide a lever to permit tilting said valve into a dispensing state.

4. The improvement of claim 2 further comprising: a plate on the base of said button extending outboard of said button to provide a lever to permit tilting said valve into a dispensing state.

5. The improvement of claim 1 wherein, in said sealed state, said stabilizing pinch is provided by (a) the outside diameter of said stem button being less than the inside diameter of said valve cup and (b) the upper surface of said button being higher than the lower surface of said valve cup.

6. The improvement of claim 2 wherein, in said sealed state, said stabilizing pinch is provided by (a) the outside diameter of said stem button being less than the inside diameter of said valve cup and (b) the upper surface of said button being higher than the lower surface of said valve cup.

7. The improvement of claim 3 wherein, in said sealed state, said stabilizing pinch is provided by (a) the outside diameter of said stem button being less than the inside diameter of said valve cup and (b) the upper surface of said button being higher than the lower surface of said valve cup.

8. The improvement of claim 4 wherein, in said sealed state, said stabilizing pinch is provided by (a) the outside diameter of said stem button being less than the inside diameter of said valve cup and (b) the upper surface of said button being higher than the lower surface of said valve cup.

9. The improvement of claim 1 wherein: The durometer of said grommet is sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated.

10. The improvement of claim 2 wherein: The durometer of said grommet is sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated.

11. The improvement of claim 3 wherein: The durometer of said grommet is sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated.

12. The improvement of claim 4 wherein: The durometer of said grommet is sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated.

13. The improvement of claim 5 wherein: The durometer of said grommet is sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated.

14. The improvement of claim 6 wherein: The durometer of said grommet is sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated.

15. The improvement of claim 7 wherein: The durometer of said grommet is sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated.

16. The improvement of claim 8 wherein: The durometer of said grommet is sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated.

17. The improvement of claim 3 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

18. The improvement of claim 4 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

19. The improvement of claim 7 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

20. The improvement of claim 8 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

21. The improvement of claim 11 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

22. The improvement of claim 12 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

23. The improvement of claim 13 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

24. The improvement of claim 16 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

25. The improvement of claim 17 wherein: in said sealed state, there is a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.

26. In a valve for use with a pressurized container for dispensing a product, the valve having a stem with a button, an annular mounting cup and an annular sealing grommet made of a resilient material, the stem extending through a central opening of the grommet, the valve having a sealed state and a dispensing state, the improvement to provide enhanced shelf-life comprising:

in said sealed state, said button of said stem compressing an annular segment of said grommet at said central opening in said grommet to create a tunnel for said button within said grommet,

in said sealed state, said button providing a seal between the surface of said button and the tunnel surface of the compressed grommet, said button also providing a stabilizing pinch of said grommet between said button and said mounting cup,

the lower portion of said stem having an interference fit relation with the adjacent portion of said grommet.

in said sealed state, said stabilizing pinch provided by (a) the outside diameter of said stem button being less than the inside diameter of said valve cup and (b) the upper surface of said button being higher than the lower surface of said valve cup,

the durometer of said grommet being sufficiently low to permit said button to create said tunnel and sufficiently high to assure a return to a sealed state when the dispensing state is terminated,

27. The improvement of claim 26 further comprising:

a plate on the base of said button extending outboard of said button to provide a lever to permit tilting said valve into a dispensing state.

in said sealed state, a gap between the upper surface of said plate and the lower surface of said grommet, said gap being sufficiently great to prevent said grommet from contacting said plate when pressure causes said grommet to distort by flaring downward.