GB2103767A

GB2103767A - Ball valve

Info

Publication number: GB2103767A
Application number: GB08222218A
Authority: GB
Inventors: Muhammad Iobal
Original assignee: Pegler Ltd
Current assignee: Pegler Ltd
Priority date: 1981-08-13
Filing date: 1982-08-02
Publication date: 1983-02-23
Also published as: GB2103767B

Abstract

A ball valve having a body part (10) with a through bore (12) and a spherical ball member (14) with a bore portion (16) which can be aligned with the bore of the body part so that the valve is fully open or brought to a position extending at right angles to said bore so that the valve is closed. So that the valve can be manufactured at relatively low cost, the spherical ball member (14) is urged into abutment with a fluid seal (18) located at what in use of the valve will be its downstream side, by means of a retaining ring element (24) having outwardly inclined resilient gripping tabs (26) which engage a plain portion (28) of the bore of the body part to prevent it from moving away from the ball member. <IMAGE>

Description

SPECIFICATION Ball valve The invention relates to ball valves.

Ball valves are well known for the shutting off of fluid flow in pipes.They are used for a wide variety of applications, that is to say in pipelines carrying all kinds of fluids, the material of which they are made being selected according to the particular application.

The main advantages possessed by ball valves are simplicity of construction and the fact that they have very few component parts, and the fact that when open they exhibit full bore flow without any restriction of fluid flow.

A conventional ball valve has a body part with a through bore and a spherical ball member with a bore portion which can be aligned with the bore of the body part so that the valve is fully open or brought to a position extending at right angles to said bore so that the valve is closed.

The valve has a suitable fluid seal on at least one side of the sperhical bail member, that is to say a seal which must be on the downstream side of the ball member when the valve is in use, the fluid seal at that side of the ball member bearing against a shoulder formed within the bore of the body part. On the other side of the ball member there is usually an annular nut screwthreaded within the bore of the body part, the nut acting either directly against the ball member or acting through a further fluid seal to urge the ball member into abutment with the first mentioned fluid seal.The forming of a screwthread within the bore portion of the body part is a relatively expensive operation, that is to say constitutes a substantial part of the entire cost of machining the body part if the latter is made of metal and represents a problem if the body part is to be of moulded plastics construction.

The invention aims to provide a construction of ball valve which does not require the provision of the screwthread referred to within the bore of the body part and which can thus be manufactured at relatively low cost.

According to the invention, there is provided a ball valve including a body part with a through bore and a spherical ball member with a bore portion which can be aligned with the bore of the body part so that the valve is fully open or brought to a position extending at right angles to said bore so that the valve is closed, the valve having a fluid seal at least on the side of the ball member which in use of the valve will be the downstream side of the ball member, the other side of the ball member being acted on by an annular retaining ring element having outwardly inclined resilient gripping tabs engaging a plain portion of the bore of the body part, the arrangement being such that the annular retaining ring element, on being entered into the bore of the body part on assembly of the valve, can act against the ball member to pre-load it against the fluid seal but is prevented from moving away from said ball member by virtue of the engagement of the outer ends of the resilient gripping tabs with the plain portion of the bore of the body part. The fluid seal will preferably be constituted by a resilient O-ring and the annular retaining ring element will preferably bear against the spherical ball member through a washer, the latter either being a resilient washer or a metal washer with a seating surface complementary to the shape of the ball member.A spindle having a key piece capable of engaging a slot in the spherical ball member will preferably be fitted in position from the inside of the bore in the body part, a shoulder formed on said spindle being capable of engaging a stepped part of a radial aperture in which the spindle is fitted, and in this case an outer end of the spindle will be adapted for the connection of an extraneous key or for the fitment of a handle by means of which the spherical ball member is to be turned.On the other hand, a spindle capable of being plugged into driving engagement with the spherical ball may be fitted in position in a radial aperture in the body part from the outside of said body part and in this case an outer end of the spindle may be adapted for the connection of an extraneous key or for the fitment of a handle, or may be formed integrally with a handle part, by means of which the spherical ball member is to be turned. In either case, the spindle may be encircled by an O-ring for sealing the aperture against leakage.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal section through a bail valve embodying the invention, and Fig. 2 is a view on the direction of arrow 2 in Fig. 1.

Referring now to the drawings, the ball valve there illustrated includes a body part 10 with a through bore 12 and a spherical ball member 14 with a bore portion 1 6 which can be aligned with the bore of the body part so that the valve is fully open, as shown in Fig. 1, or can be brought to a position extending at right angles to said bore so that the valve is closed.

The valve has a fluid seal on the side of the ball member which, in use of the valve, will be the downstream side of the ball member, the fluid seal in the illustrated example being shown to be constituted by a rubber O-ring 1 8 abutting against a shoulder 20 formed within the bore of the body part. The other side of the ball member is acted on by an annular abutment ring 22, which has a seating surface complementary to the shape of the ball member, and by an annular retaining ring element 24 which bears against the abutment ring.The annular retaining ring element has a plurality of outwardly inclined resilient gripping tabs 26, as shown, engaging a plain portion 28 of the bore of the body part, and the arrangement is such that the annular retaining ring element, on being entered into a bore of the body part on assembly of the valve, can act against the ball member to pre-load it against the O-ring 1 8 but is prevented from moving away from the ball member by virtue of the engagement of the outer ends of the resilient gripping tabs with the plain portion of the bore of the body part.

A spindle generally indicated 29, having a key piece 30 capable of engaging a slot in the spherical ball member, is provided for turning the ball member between open and closed positions.

The spindle is rotatably mounted in the body part in a very simple manner, being fitted in position from inside the bore in the body part before the ball member has been fitted in position. As shown, a shoulder 32 is formed on the spindle and is capable of engaging a stepped part of the radial aperture in the body part in which the spindle is fitted.The spindle is grooved intermediate its ends, the groove receiving an O-ring 34 for sealing the aperture against leakage. (The manner in which the spindle can be turned so that the ball member can be moved between the closed and open positions is not shown in the drawings but it will be understood that it can be formed with a screwdriver slot, with an aperture for the fitment of an Allen key, or can be provided with a square or hexagonal head for the fitment of a key or wrench.) It will be seen that the ball valve has a minimum number of parts. It can therefore be produced very economically. The fact that the bore of the body part is devoid of a screwthread for the fitment of an annular nut for retaining the ball element in position also tends to reduce costs and the assembly of the valve is made very simple.

Similarly, the fact that the spindle can be fitted into position so very simply and easily reduces the cost of manufacturing and assembly.

Depending on the particular application for which the valve is intended, the body part and the component parts can be made of various materials. If made of metal, the cost of machining the body part of the illustrated embodiment will be relatively low due to the absence of a screwthread within the bore and due also to the absence of a screwthread in the aperture in which the spindle is to be mounted. If moulded in a synthetic plastics material, the body part will be capable of being produced very economically for these same reasons.

Various modifications may of course be made.

For example, it may be possible to provide an adequate fluid seal between the ball member and the shoulder formed within the bore of the body part without the need for O-ring 18 if the abutting surfaces are fairly soft (and especially if the valve will not require to be operated many times throughout its working life). On the other hand, it may be desired to provide a fluid seal on both sides of the ball member; this may be achieved by making the abutment ring of a relatively soft material or by fitting a further O-ring seal at that side of said ball member. Furthermore, it will be understood that it is not essential that the spindle 29 should be fitted in position from inside the bore of the body part before the ball member has been fitted in position; it could be fitted from outside the body part but in that case would require alternative means for retaining it in position.On the other hand, in that case the outer end of the spindle need not necessarily be adapted for the connection of an extraneous key or for the fitment of a handle but could be formed integrally with a handle part by means of which the spherical ball member could be turned. It will be understood that the need for the key piece and slot connection between the spindle and spherical ball member in the illustrated embodiment is dictated by the fact that the ball member is to be capable of being entered into its seated position in the body part with the spindle already in position in the body, that is to say with the key piece of the spindle lying longitudinally of the body part to allow the ball member to be slid into position. However, if the spindle is fitted in position from outside the body part it could have any convenient form of non-rotatable plug-in driving connection with the ball member.

It will of course be understood that the opposite ends of the body part need not necessarily be adapted for the fitment of compression type fittings as in the illustrated embodiment. The body part could be designed for the fitment of any other type of pipe connection.

Claims

1. A ball valve including a body part with a through bore and a spherical ball member with a bore portion which can be aligned with the bore of the body part so that the valve is fully open or brought to a position extending at right angles to said bore so that the valve is closed, the valve having a fluid seal at least on the side of the ball member which in use of the valve will be the downstream side of the ball member, the other side of the ball member being acted on by an annular retaining ring element having outwardly inclined resilient gripping tabs engaging a plain portion of the bore of the body part, the arrangement being such that the annular retaining ring element, on being entered into the bore of the body part on assembly of the valve, can act against the ball member to pre-load it against the fluid seal but is prevented from moving away from said ball member by virtue of the engagement of the outer ends of the resilient gripping tabs with the plain portion of the bore of the body part.

2. A ball valve according to claim 1, in which the fluid seal is constituted by a resilient O-ring.

3. A ball valve according to either one of the preceding claims, in which the annular retaining ring element bears against the spherical ball member through a washer, the latter either being a resilient washer or a metal washer with a seating surface complementary to the shape of the ball member.

4. A ball valve according to any one of the preceding claims, in which a spindle having a key piece capable of engaging a slot in the spherical ball member is fitted in position from the inside of the bore in the body part, a shoulder formed on said spindle being capable of engaging a stepped part of a radial aperture in which the spindle is fitted, an outer end of the spindle being adapted for the connection of an extraneous key or for the fitment of a handle by means of which the spherical ball member is to be turned.

5. A ball valve according to any one of claims 1 to 3, in which a spindle capable of being plugged into driving engagement with the spherical ball is fitted in position in a radial aperture in the body part from the outside of said body part.

6. A ball valve according to claim 5, in which an outer end of the spindle is adapted for the connection of an extraneous key or for the fitment of a handle, or formed integrally with a handle part, by means of which the spherical ball member is to be turned.

7. A ball valve according to any one of claims 4 to 6 in which the spindle is encircled by an O-ring for sealing the aperture against leakage.

8. A ball valve constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.