GB2111646A

GB2111646A - Valve

Info

Publication number: GB2111646A
Application number: GB8136847A
Authority: GB
Inventors: Geoffrey Train; Alexander Bissett Laird
Original assignee: Thorn Domestic Appliances Electrical Ltd
Current assignee: Electrical and Musical Industries Ltd
Priority date: 1981-12-07
Filing date: 1981-12-07
Publication date: 1983-07-06

Abstract

The body of a valve, for a cylinder of pressurized carbon dioxide, in which has a main bore 13 with a reduced diameter bore 16 extending from one end to provide a shoulder 17 which forms a valve seat. The valve member includes a head 22 slidable in the main bore and a stem 23 slidable in the reduced diameter bore. The valve member has, at the junction of the head and stem, a resilient sealing ring 18 secured or bonded thereto, this, in use, engaging the valve seat. The valve member and a retaining spring 24 are all insertable from the other end of the valve body for ease of manufacture. <IMAGE>

Description

SPECIFICATION Valve The present invention relates to valves, and in particular to valves for gas cylinders which may, for example, bused in aerated drinks machines.

Valves currently used for this latter purpose are rather complex, and therefore costly to manufacture, and are found to have a tendency to leak.

It is now proposed, according to the present invention, to provide a valve comprising a valve body having a first end and a second end opposite thereto, a main bore of a given diameter extending axially from the first end towards the second end, a reduced diameter bore extending axially from the second end and coaxial with the main bore, the valve body having an annular shoulder at the junction of the main bore and the reduced diameter bore, the valve member having a valve head axially slidable in the main bore, an integral valve stem on said valve head axially slidable in the reduced diameter bore, a resilient sealing ring secured or bonded on the valve member at the junction between the valve stem and the annular face of the valve head surrounding the valve stem and a spring in the main bore to urge the valve member towards the second end, sealingly to engage the sealing ring with the annular shoulder on the body, the valve member and stem, the sealing ring and spring being insertable from the first end, the valve stem being actuable from the second end to compress the spring to unseat the sealing ring from the annular shoulder.

Such a structure has been found to be very reliable while being inexpensive to manufacture. Because the shoulder between the main bore and the bore of reduced diameter is used as the seat, it is not necessary to have any special inserts which are conventionally used to form the valve seat. The assembly being all from the first end greatly simplifies the manufacture.

It has been found most important to have the sealing ring secured or bonded to the valve member at the junction between the valve stem and the valve head. Such an arrangement does not rely on the resilience of the sealing ring itself to retain it in place and equally importantly the arrangement is such that any permeation of gas which might occur through the seal does not cause the seal to lift. This can be a problem because if the seal lifts first of all it may become disconnected from the valve member and secondly may not adequately allow the valve to be opened.

Preferably the actual body of the valve is simply bored out using a special boring tool which may have a particular profile to form the shoulder.

In order further to reduce the cost of the valve, the valve stem may be made, for example, as a plastics material moulding, so that it is integral with the valve head.

The actual means for positioning the sealing ring may take many forms. For example the sealing ring may be bonded by an adhesive directly to the annular face and the valve stem in which case the junction point is preferably preformed to the shape of the seal which may, for example, bean O-ring. An alternative arrangement is that the sealing ring is bonded to a material, such as Loctite, which is moulded into an annular groove in the valve stem adjacent the junction with the valve head.

A further proposal is for the valve head to have a peripheral skirt which is deformed or peeved over to secure the sealing ring in place. A further possibility is for the sealing ring to be directly moulded in situ onto the valve member.

The spring may be retained in the main bore by a retaining means such as a plug which is screwable into an enlarged portion of the main bore at the first end. This plug may itself comprise a piercing nozzle which is adapted to pierce the diaphragm of a disposable gas container. Alternatively, where a non-disposable gas container is used, and the valve is permanently maintained on the container, the neck of the cylinder of gas itself may be used as a retaining means.

Advantageously a lateral bore communicates with the main bore intermediate the ends thereof, the lateral bore accommodating a bursting disc which is retained in position by a bursting disc plug having oppositely arranged venting ports.

In orderthatthe present invention may readily be understood, the following description is given, merely by way of example, reference being made to the accompanying drawings in which FIGURE 1 is a cross-section through one embodiment of valve according to the invention shown mounted on the neck of a gas cylinder; and FIGURES 2,3,4 and 5 are side elevations, on an enlarged scale, of the valve member of Figure 1 and of three further embodiments of such valve member.

Referring first to Figure 1, the valve illustrated therein comprises a valve body 10 provided adjacent its upper end with an external thread 11 and adjacent its lower end with a hexagon spanner-engaging portion 12. The body 10 is preferably made of a material such as brass and is provided with an axially extending main bore 13 extending from a first end 14thereof towards a second upper end 15. The main bore 13 does not extend fullyto the end 13, but communicates with a reduced diameter bore 16 coaxial with the main bore, the two meeting at the radially extending annular shoulder 17.

At its upper or second end, the reduced diameter portion 16 is provided with a wide conically tapered mouth 20, opening into a recess 19.

Axially slidable within the main bore is a valve member indicated by the general reference numeral 21, this comprising a valve head 22 and an integral valve stem 23 which slides within the bore 16. It will be seen that the upper end of the stem 16 is located within the conical mouth 20 and recess 20A. A helical coil compression spring 24 is located within the main bore 13 and urges the valve body 21 axially upwards. Onto a shoulder 25 formed on the upper end face of the valve head 22 and surrounding the valve stem 23 and within a peripheral skirt 19 is moulded a sealing ring 18. This can be seen more readily in Figure 2.

In order to retain the spring in place there is provided a spring retaining plug 36 which has an external thread for engaging an internal thread 29, the lower surface of the plug 36 being provided with a nozzle 37 which, as can be seen from Figure 4, is of hexagonal form to enable the plug to be screwed into place. The plug has an annular shoulder 38 and this is sealingly engaged against an O-ring 39 which is retained in place by a protection 40.

The lower end of the nozzle is tapered to an annular knife edge 41 which is used to pierce the membrane of the disposable gas cylinder. Also within the widened bore at the lower end of the main bore is a further seal 42. Thus, when a disposable container is screwed into the internal thread 29 the top is initially urged against the seal 42 and shortly thereafter the knife edge 41 pierces the membrane of the disposable cylinder so that gas can be discharged up through the bore 43, via a filter 26 and into the main bore 13.

A lateral bore 30 communicates with the main bore 13 intermediate the ends thereof and this accommodates a sealing ring 31 and a bursting disc 32 of conventional type, retained by a bursting disc plug 33 having oppositely extending vent ports 34 and 35.

In use a container or cylinder 28 is screwed onto the thread 29 and the spring 24 urges the valve member 21 so that the sealing ring 17, 18 thereof is in abutting relation with the annular shoulder 17 to form a seal so that gas cannot escape from the cylinder 28. When one wishes to discharge some gas, for example, in an aerated drinks machine, one depresses the stem 23 which unseats the sealing ring 18 from the annular shoulder 17.There is a small clearance between the bore 13 and valve member, and between the bore 16 and the valve stem 23 which is sufficient to allow the gas to escape, but is not too large, so there is always a good measure of axial alignment of the valve member within the bores.

Other forms of valve member are shown in Figures 3,4 and 5. In Figure 3the sealing ring 18A is of generally similar form, although it could be a simple O-ring, and it is retained in the valve member by the skirt portion 19A being deformed or peeved inwardly. An adhesive may also be applied if desired.

In the Figure 4 construction there is no skirt corresponding to the skirt 19 but the junction betweenthevalve stem 16B and the annularshoulder 25B is formed with a circular cross-section groove 37 to accommodate the sealing ring which is in the form of an O-ring 18B. The two are secured together by a suitable adhesive. In fact it is quite difficult to find an adhesive which is capable of providing a strong bond with both the resilient sealing ring and the body of the valve member. This difficulty is overcome in the construction of Figure 5 in which the sealing ring 18C is bounded to a collar 38 of "Loctite" which is moulded into an annular groove 39 formed at the junction of the annular face 25C and the valve stem 16C. While the Loctite does not actually bond to the valve stem it forms a key in the groove 39.

Claims

1. A valve comprising a valve body having a first end and a second end opposite thereto, a main bore of a given diameter extending axially from the first end towards the second end, a reduced diameter bore extending axially from the second end and coaxial with the main bore, the valve body having an annular shoulder at the junction of the main bore and the reduced diameter bore, the valve rrrember having a valve head axially slidable in the main bore, an integral valve stem on said valve head axially- slidable in the reduced diameter bore, a resilient sealing ring secured or bonded on the valve member at the junction between the valve stem and the annular face of the valve head surrounding the valve stem and a spring in the main bore to urge the valve member towards the second end, sealingly to engage the sealing ring with the annular shoulder on the body, the valve member and stem, the sealingly ring and spring being insertable from the first end, the valve stem being actuable from the second end to compress the spring to unseat the sealing ring from the annular shoulder.

2. Avalveaccordingto claim 1, wherein the sealing ring is an O-ring.

3. A valve according to claim 1 or 2, wherein the sealing ring is bonded by an adhesive to said annular face and the valve stem.

4. A valve according to claim 1 or 2 wherein the sealing ring is bonded to a material which is moulded into an annular groove in the valve stem adjacent said junction with the valve head.

5. A valve according to claim 1 or 2, wherein the sealing ring is secured by a deformed portion of the valve head.

6. Avalveaccordingtoclaim 1, wherein the sealing ring is moulded in situ into the valve member.

7. Avalve according to any preceding claim in which means are provided at the first end to- rete the spring in the main bore.

8. Avalve according to claim 7 wherein said retaining means comprise a plug screwable into an enlarged portion of the main bore at the firstend.

9. A valve according to claim 7 or 8, wherein said plug comprises a piercing nonle adapted to pierce the diaphragm of a disposable gas container

10. A valve according to claim' 9 and fuprtter comprising an O-ring seal between said plug and the valve body.

11. A valve according to any preceding claims and further comprising a lateral bore communicating with the main bore intermediate the ends thereof, the lateral bore accommodating a bursting disc retained in position by a bursting disc plug having oppositely arranged venting ports.

12. Avalve substantially as hereinbefore ds scribed with reference to and as illustrated in Figures 1 and 2 of the accompanying drawings.

13. A valve according to claim 12 modified substantially as hereinbefore described with refer ence to and as illustrated in Figure 3 of the accompanying drawings.

14. Avalve according to claim 12 modified substantially as hereinbefore described with reference to and as illustrated in Figure 4 of the accompanying drawings.

15. A valve according to claim 12 modified substantially as hereinbefore described with reference to and as illustrated in Figure 5 of the accompanying drawings.

New claims or amendments to claims filed on 10 Now 32.

Superseded claim 1 New or amended claim 1

1. A valve comprising a valve body having a first end and a second end opposite thereto, a main bore of a given diameter extending axially from the first end towards the second end, a reduced diameter bore extending axially from the second end and coaxial with the main bore, the valve body having an annular shoulder at the junction of the main bore and the reduced diameter bore, the valve member having a valve head axially slidable in the main bore and in contact therewith, an integral valve stem on said valve head axially slidable in the reduced diameter bore and in contact therewith, a resilient sealing ring secured or bonded on the valve member at the junction between the valve stem and the annular face of the valve head surrounding the valve stem and a spring in the main bore to urge the valve member towards the second end, sealingly to engage the sealing ring with the annular shoulder on the body, the valve member and stem, the sealing ring and spring being insertable from the first end, the valve stem being actuable from the second end to compress the spring to unseat the sealing ring from the annular shoulder.