WO1993025830A1

WO1993025830A1 - Gasket and valve incorporating same

Info

Publication number: WO1993025830A1
Application number: PCT/AU1993/000271
Authority: WO
Inventors: David John Batchen; John F. Treloar
Original assignee: L.G. Equipment Pty. Limited
Priority date: 1992-06-05
Filing date: 1993-06-07
Publication date: 1993-12-23
Also published as: CA2076985A1

Abstract

A gasket (40) comprises a ring of resilient, flexible material having generally opposed first or upper (41) and second or lower (42) sealing surfaces interconnected by connecting structure (43) in a manner whereby a volume (44) is defined between the upper and lower sealing surfaces (41, 42) into which the surfaces (41, 42) can resiliently deform when the surfaces (41, 42) are urged towards each other during assembly of the gasket (40), and internal pressure within the volume (44) can maintain a seal when adjacent sealing faces against which the sealing surfaces (41, 42) seal are retracted from each other by an initial amount. The gasket (40) is especially suited for sealing a connection between a dispensing nozzle and a filler valve of LPG equipment.

Description

GASKET AND VALVE INCORPORATING SAME

TECHNICAL FIELD

The present invention relates to a gasket and, in particular, to a gasket suited particularly (but not

exclusively) for use to seal a connection between a nozzle and a filler valve.

BACKGROUND ART

In the particular context of the supply of liquefied petroleum gas (L.P.G.) for motor vehicles and the like there exisrs a problem in relation to gasketing.

Standards Australia (AS 1596) has adopted the 1 3/4" ACME thread system for coupling pipe and hose systems carrying liquefied petroleum gas (L.P.G.), particularly associated with automotive refuelling of such gas from driveway flowmeters to motor vehicle L.P.G. onboard tanks.

L.P.G. is a highly inflammable liquid at pressures of 1600 kPa and higher. When escaping to atmospheric pressure, the liquid expands rapidly to a gaseous volume in excess of 250 times its liquid state. Such rapid expansion causes a sharp drop in temperature of the liquid to gas, which can be dangerous to human flesh, more so in the liquid state, causing "freeze" burns.

The Australian marketers of L.P.G. as a fuel for automotive propulsion, have elected to "self serve" the product, in much the same manner as standard gasolene from a driveway dispenser. However, the use of L.P.G. dispensing nozzles by laypersons provides for the need for greater care in carrying out refuelling operations safely and efficiently There are two associated products which are used in the coupling process between the driveway dispenser and the automobile filling connection, namely a dispensing nozzle and a filler valve.

The filler valve has an external 1 3/4" ACME thread connection with associated non-return valves, and the nozzle has an internal 1 3/4" ACME thread 12. The coupling process is relatively easy with a pressure proof joint being provided by a synthetic rubber gasket contained in the filler valve. The completed coupling can be likened to that associated with a screwed garden hose/tap connection except that the design constraints are more onerous due to factors such as design standards of filler valve assemblies and associated

components and the hazardous nature of the gas contained by those assemblies.

The gasket is a critical component as it provides the seal between an inner surface of the filler valve neck and a leading surface of the nose piece of the nozzle. Compressive pressure is applied to the gasket when an operator screws a swivel nut of the nozzle firmly onto an external thread connection of the filler valve neck.

In practice, the quality of the seal achieved is very sensitive to the amount of rotation applied to the swivel nut. In some cases a 1/8th turn of that swivel nut can be the difference between a secure seal and a leaking seal.

The nozzle is provided with a latching device which allows "hands free" dispensing of L.P.G. into the vehicle tank via the filler valve, after proper connection has been made. Such proper connection is in the hands of the "self serve" operator, normally the vehicle driver. Disconnection is also usually the responsibility of the driver.

On some occasions, the connection of nozzle to filler valve is not complete, due to several reasons, the main one being insufficient torque being applied to the swivel nut during the connection process. Also, the gasket in the filler valve might have deteriorated or come out of its retaining groove, eliminating the possibility of a correct leak-proof connection.

Similarly, the disconnection process provides for a correct procedure, and sometimes the nozzle is unscrewed from the filler valve without firstly releasing the operating lever and so closing the nozzle's main valve. If this happens, gas escape can occur in large volumes from the connection with possibilities of severe freeze burns

occurring to the operator.

Correct coupling and uncoupling of the system requires, as mentioned above, the gasket to be in sound condition, plus a coupling and uncoupling procedure based upon a full

"safety" understanding of the operation.

It is an object of the present invention to overcome or ameliorate one or more of the abovementioned disadvantages of the prior art.

DISCLOSURE OF INVENTION

According to one aspect of the invention, there is provided a gasket comprising a ring of resilient, flexible material having generally opposed first or upper and second or lower sealing surfaces interconnected by connecting means in a manner whereby a volume is defined between said upper and lower sealing surfaces into which said surfaces can resiliently deform when said surfaces are urged towards each other.

According to a further aspect of the invention there is provided a gasket comprising a ring of resilient, flexible material having generally opposed first or upper and second or lower sealing surfaces interconnected by connecting means in a manner whereby a volume is defined between said upper and lower sealing surfaces into which said surfaces can resiliently deform when said surfaces are urged towards each other; and whereby said sealing surfaces are urged apart under the influence of a pressure differential between said volume and the outside of said sealing surfaces and whereby internal pressure can maintain the seal when sealing faces against which said sealing surfaces seal are retracted from each other.

According to a still further aspect of the invention there is provided a filler valve gasket for use in sealing a connection between a dispensing nozzle and a filler valve; said gasket comprising a ring of resilient, flexible material having generally opposed first or upper and second or lower sealing surfaces interconnected by connecting means in a manner whereby a volume is defined between said upper and lower sealing surfaces into which said surfaces can

resiliently deform when said surfaces are urged towards each other during connection of said dispensing nozzle to said filler valve.

According to a still further aspect of the invention there is provided an L.P.G. filler valve gasket for use in sealing a connection between an L.P.G. dispensing nozzle and an L.P.G. filler valve located on a vehicle; said gasket comprising a ring of resilient, flexible material having generally opposed upper and lower sealing surfaces

interconnected by connecting means in a manner whereby a volume is defined between said upper and lower sealing surfaces into which said surfaces can resiliently collapse when said surfaces are urged towards each other during connection of said dispensing nozzle to said filler valve whereby a seal is formed between a leading surface of said nozzle and an internal surface of a neck portion of said filler valve.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily

understood and put into practical effect, reference will now be made to the accompanying drawings wherein:-

Fig. 1 is a perspective view of a prior art L.P.G.

filler valve and part of a dispensing nozzle,

Fig. 2 is a partly sectioned, side elevational

view of the dispensing nozzle shown in Fig. 1,

Fig. 3 is a cross-sectional view of the filler

valve shown in Fig. 1, Fig. 4 is a perspective view of a gasket according to one embodiment of the invention,

Fig. 5 is a cross-sectional view of the gasket

shown in Fig. 4,

Fig. 6 is a partly sectioned, side elevational

view of a filler valve showing the gasket of Figs. 4 and 5 in place, and

Fig. 7 is an enlarged view of the top portion of

Fig. 6.

BEST MODE FOR CARRYING OUT THE INVENTION

The prior art arrangement shown in Fig. 1, includes a receptacle assembly 10 adapted to receive an L.P.G. nozzle 15. The receptacle assembly 10 comprises a shroud 11 which envelops an externally threaded neck 12 of a filler valve 25. The top of the threaded neck 12 protrudes sufficiently into the volume of the shroud 11 so as to be attachable to nozzle 15 by the action of rotating rotatable sleeve 16 so that the leading internally threaded portion 17 of rotatable sleeve 16 (see Fig. 2) threadedly engages the threaded neck 12 of the filler valve 25.

Fig. 3 is a cross-section of receptacle assembly shown in Fig. 1 and is particularly suited to installation on motor vehicles and the like.

The receptacle assembly 10 shown in Fig. 3 includes the shroud 11 which envelops the threaded neck 12 of the filler valve 25. The filler valve neck 12 has a top threaded portion 20 onto which a cap 21 is screwed when a hose nozzle is not connected. A non-gas-tight door or cover 22 covers across the very top of the shroud 11 so as to provide a cosmetic cover in alignment with vehicle body panels 18.

A diaphragm 13 engages in a slot 23 in the inner side wall of the shroud 11. Dimension D of the diaphragm 13 is sized so that leading edge 19 of diaphragm 13 forms an interference fit with the external surface of sleeve 16 of nozzle 15 when the sleeve 16 is threadedly engaged with the threaded portion 20 of the filler valve neck as well as immediately before and after such engagement is made.

Vent aperture 14 allows L.P.G. fuel or gas trapped within the volume defined by the nozzle 15, the diaphragm 13, the shroud 11 and the top of the filler valve neck to be vented from this volume in a direction away from the nozzle

15.

This arrangement is effective in preventing L.P.G. fuel or gas which escapes from the nozzle/filler valve connection while the nozzle 15 is connected to the filler valve 25 or while the nozzle is engaged with the diaphragm 13 from

"blowing back" in the direction of the nozzle 15.

The shroud 11 can form an integral part of the vehicle body panels 18 or can be attached to those panels by suitable mechanical attachment means.

A retainer flange 24 may be utilised to clamp the shroud 11 to the underside of body panels 18.

The receptacle assembly 10 can be used in a free-standing mode as well as in the situation where the filler valve does not need to be hidden below the body line of a vehicle. The filler valve neck 12 has an annular interval shoulder 26 which constitutes a seat for a sealing gasket 27, which, in the prior art, is merely an annulus of constant cross-section as can be seen in Fig. 3.

A gasket 40 according to a preferred embodiment of the invention is shown in Figs. 4 and 5 and is shown

diagrammatically in position in a filler valve in Figs. 6 and 7.

The gasket 40 is generally in the shape of a ring and comprises a first or upper sealing surface 41 and a second or lower sealing surface 42 interconnected by connecting

structure 43 whereby a volume 44 is defined between the upper and lower sealing surfaces 41, 42 into which the surfaces 41, 42 can be resiliently deformed when the surfaces are urged towards each other during connection of the dispensing nozzle 21 to the filler valve neck 10 of the filler valve 25.

The upper sealing surface 41 and part of the connecting structure 43 are in the form of an upper conical flange 45 which is mated in a mirror image manner to lower sealing surface 42 and part of the connecting structure 43 which isin the shape of a lower conical flange 46.

The connecting structure 43 between the flanges 45, 46 is in the form of a flange or rim 47 which locates within a correspondingly shaped recess 48 within the filler valve neck 10. As can be seen in Figs. 6 and 7, when the gasket 40 is located in the recess 48, the lower flange 46 is somewhat compressed.

In use, the upper surface 41 of the gasket 40 is urged tαwards lower surface 42 of the gasket 40 by the action of the leading surface of the nose piece 15 of the nozzle 21. An effective seal commences to be formed from this time thereby allowing for a seal to be maintained between nozzle 21 and neck 10 over a greater distance of penetration of nose piece 15 than would be the case where the flat prior art gasket of the prior art is utilised in the same position.

Under normal conditions it is expected that when gasket 40 is compressed, as in the case when nose piece 15 of the nozzle 21 is properly located within neck 10, that the gasket 40 will adopt a closed height similar to that of a prior art flat gasket 16.

In a particularly preferred embodiment of the

invention, the gasket 40 is made of a material marketed by J.C. Ludowici as TP103 which is an injection mouldable polyester thermo-plastic material. This material has good recoverability (i.e. its ability to resume its original shape after deformation) which ranges from a Durometer a hardness of 89 at +50°C to 91 at -50°C. Polyurethane may be used if the lower temperature preformance is not so critical.

In this embodiment, the gasket has an external diameter of 34.0 mm and an internal diameter of 24.0 mm. The

thickness of each flange is from 1.6 to 1.8 mm and the thickness of the rim 47 is from 2.3 to 2.5 mm. The volume 40 has planar sides constituted by the inner faces of the flanges and interconnected by a curved surface having a radius of 1.0 mm. The preferred angle between the flanges is 82.8°, the height of the gasket is 9.0 mm and the radial width of the rim 47 is 2.5 mm.

Due to its internal bellows design, L.P.G. pressure always presses the opposed gasket lips generally away from each other and towards their respective mating surfaces when the nose piece is in pressure contact with same. This is particularly so in relation to the seal between the inner lip 49 of the flange 46 and the sealing face 50 of the valve 10 as gas in the volume 44 exerts a pressure against the inner face of the flange 46 to force the lip 49 against the face 50. Due to the incorporated "memory" of the material from which the gasket 40 is made added continuous pressure is maintained against the machined face 50 of the filler valve by the lip 49 of the gasket.

Consequently, this gasket provides a seal efficiency over a movement of the nose piece with the gasket well beyond that available with the flat gasket, currently used. The potential benefits of the gasket of the invention are:

(a) the torque required to tighten the nozzle swivel nut to the filler valve is lessened. In fact, a somewhat "loose" connection of the swivel nut to the filler valve maintains pressure integrity of the coupling,

(b) the pressure integrity is maintained even if the nozzle is partially unscrewed during the filling operation,

(c) the nozzle with its main valve unwittingly open, can be unscrewed froa the filler valve for

approximately one full rotation, before gas commences to escape and this escape is initially in small quantities,

(d) it substantially enhances the necessary safety features of the coupling/uncoupling processes associated with the "self serve" principle of operation of L.P.G. automotive refuelling, improving operator confidence and lessening the possibilities of freeze burns.

The above describes only some embodiments of the present invention and modifications, obvious to those skilled in the art can be made thereto without departing from the scope and spirit of the present invention.

INDUSTRIAL APPLICABILITY

The gasket can be used with fittings for handling

L.P.G. and other fittings for handling any compressed, liquefiable gas for example bulk L.P.G./propane

installations, anhydrous ammonia installations and the like.

The gasket can also be used in conjunction with

disconnectable fittings associated with tanks on gas powered fork lifts, domestic L.P.G. installations and the like.

Claims

THE CLAIMS

1. A gasket comprising a ring of resilient, flexible material having generally opposed first or upper and second or lower sealing surfaces interconnected by connecting means in a manner whereby a volume is defined between said upper and lower sealing surfaces into which said surfaces can resiliently deform when said surfaces are urged towards each other.

2. A gasket according to claim 1 wherein the upper sealing surface and the lower sealing surface comprise, respectively, opposed conical flanges.

3. A gasket according to claim 2 wherein the conical flanges are joined about their periphery at an acute angle to a plane passing through said periphery.

4. A gasket according to claim 3 wherein said volume is open towards the centre of said gasket.

5. A gasket according to claim 4 wherein said connecting means define an outer rim to said gasket.

6. A gasket comprising a ring of resilient, flexible material having generally opposed first or upper and second or lower sealing surfaces interconnected by connecting means in a manner whereby a volume is defined between said upper and lower sealing surfaces into which said surfaces can resiliently deform when said surfaces are urged towards each other; and whereby said sealing surfaces are urged apart under the influence of a pressure differential between said volume and the outside of said sealing surfaces and whereby internal pressure can maintain the seal when sealing faces against which said sealing surfaces seal are retracted from each other.

7. A gasket according to claim 6 wherein the upper and lower sealing surfaces comprise a conical flange extending upwardly, inwardly away from a rim portion.

8. A gasket according to claim 7 wherein said upper and lower sealing surfaces are joined at the rim so as to form the connecting means.

9. A filler valve gasket for use in sealing a connection between a dispensing nozzle and a filler valve; said gasket comprising a ring of resilient, flexible material having generally opposed first or upper and second or lower sealing surfaces interconnected by connecting means in a manner whereby a volume is defined between said upper and lower sealing surfaces into which said surfaces can resiliently deform when said surfaces are urged towards each other during connection of said dispensing nozzle to said filler valve.

10. An L.P.G. filler valve gasket for use in sealing a connection between an L.P.G. dispensing nozzle and an L.P.G. filler valve located on a vehicle; said gasket comprising a ring of resilient, flexible material having generally opposed first or upper and second or lower sealing surfaces

interconnected by connecting means in a manner whereby a volume is defined between the upper and lower sealing

surfaces into which the surfaces can resiliently deform when said surfaces are urged towards each other during connection of said dispensing nozzle to said filler valve whereby a seal is formed between a leading surface of said nozzle and an internal surface of a neck portion of said filler valve.

11. An L.P.G. filler valve assembly comprising a body defining a valve chamber having an inlet thereto and an outlet therefrom, a valve member and associated valve seat in the valve chamber, and means for connecting the valve

assembly to an L.P.G. gas nozzle, said connecting means including a neck surrounding the inlet to the valve chamber, said neck having an internal seat surrounded by a locating recess and a gasket seated in the gasket, said gasket

comprising a ring of resilient, flexible material having generally opposed first or upper and second or lower sealing surfaces interconnected by connecting means in a manner whereby a volume is defined between said upper and lower sealing surfaces into which said surfaces can resiliently deform when said surfaces are urged towards each other.

12. A valve assembly according to claim 11 wherein the connecting means defines an outer rim.

13. A valve assembly according to claim 12 wherein the locating recess is larger than the thickness of the rim of the gasket but smaller than the thickness of the gasket from the outside of the rim to the outer face of the second or lower flange so that the lower flange is compressed between the top of the recess and the internal seat.

14. A valve assembly according to claim 11 wherein the volume between the upper and lower flanges extends over the internal seat in the neck so that pressure of gas within the volume forces the lower flange against the internal seat.