GB2186952A

GB2186952A - A ball valve

Info

Publication number: GB2186952A
Application number: GB08703512A
Authority: GB
Inventors: Kenneth John Walker
Original assignee: HATTERSLEY HEATON Ltd
Current assignee: HATTERSLEY HEATON Ltd
Priority date: 1986-02-14
Filing date: 1987-02-16
Publication date: 1987-08-26
Also published as: GB8703512D0

Abstract

A ball valve comprises seat means and a ball 9 so disposed that they may be removed together from a housing part 3 which defines the inlet and outlet. As shown a cage 11 supports two seating arrangements 12 and 13 disposed on opposite sides of the ball 9 to form a self-sealing wedge shaped assembly. <IMAGE>

Description

SPECIFICATION A ball valve The present invention relates to a ball valve.

Ball valves are usually employed to shut off fluid flow through a fluid flow line, and are generally known. One such known valve comprises a ball disposed in a housing which defines a fluid inlet and a fluid outlet. The ball defines a through passage, which in one position is aligned with the inlet and the outlet to permitfluidflowthrough thevalveand in another position disaligned to prevent such fluid flow. Seats are disposed between the ball and the housing to prevent or severely restrict fluid flow between the ball and the adjacent wall ofthe housing. The seats require maintenance to ensure the valve remains in correct operating condition. Access to these seats may be gained by splitting the housing and removing the ball.

This access may be restricted and therefore makes maintenance difficult. In certain circumstances for example, the valve may be in a hazardous area, possibly enclosed in concrete and access thereto normally available only by robot.

According to the present invention, there is pro vided a ball valve comprising a valve housing defining an inlet and an outlet, a valve ball disposed within the housing between the inlet and the outlet and movable between a first position in which fluid flow between inlet and outlet is prevented and a second position in which fluid flow between inlet and outlet is permitted, and seat means for the ball disposed between the housing and the ball to reducefluid leakagetherebe- tween, the seat means and the ball being so disposed that they may be removed together from the housing.

In a preferred embodimentofthe invention,the ball is disposed between two seating arrangements which are both supported in a cage. This cage is in turn supported onashaftwhich forms parts an actuator mechanism. The valve housing comprises two parts and the actuator mechanism extends through one part. When the parts are separated, the actuator mechanism, ball and seating arrangements are withdrawn with one of the parts leaving the ball and seating arrangements projecting from that part to facilitate maintenance.

In order that the invention may be more clearly understood, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a cross-section of a ball valve, and Figure 2 shows a viewsimilarto Figure 1 butofa modification of the valve of Figure 1.

Referring to the drawing, the ball valve comprises a cast metal housing 1. This housing 1 is split into two parts 2 and 3 which are bolted together by means of pairs of bolts 4 and 5, the line of separation of the parts being indicated at 6. A gasket is disposed between the two parts. The lower part3 ofthe housing defines a fluid inlet7, a fluid outlet8 and a chamberforthe ball9 of valve disposed between the inlet 7 and outlet 8. The ball 9, which defines a th rough fluid bore 10, is disposed within a stainless steel cage 11 which supports two seating arrangements 12 and 13 disposed on opposite sides respectively of the ball 9 to form a self sealing wedge shaped assembly.Each seating arrangement 12, 13 comprises a support 18, 19 formed to accept an annular soft material seat such as a graphited TFE (Tetrafluoroethylene) seat 14, 15, on one side and an annular soft material secondary seat such as a graphited TFE seat 16, 17 on the other. Seats 16 and 17 on the sloping faces of the assembly seat and seal between the housing part 3 and seat supports 18 and '19 respectively and seats 14 and 15 seat and seal between seat supports 18 and 19 and the ball 9.

The cage 11 is connected to a shaft 20 which forms part of an actuator mechanism indicated generally by the reference numeral 21. The mechanism 21 aiso comprises an actuator lever 22. The shaft extends through locknuts 23, which fix the lever 22 to the shaft 20, a washer 24, a keep plate 25, a spring adjuster 26, disc springs 27, thrust plate retainer 28, thrust plate 29, stainless steel spring 30, gland rings 31 which incorporate secondary graphite seals 32, stainless steel shims 33 and primary chevron type P.T.F.E. seals 34. The lower end of the shaft informed with a flange 35 on which cage 11 sits and a spigot 36 which extends into a complementary recess in the ball 9. Rotation of the lever22 through one quarterturn rotatesthe ball 9 through shaft 22 between valve open and valve closed positions.

When access to the ball valve seat is required for maintenance, bolts 4 and 5 are removed enabling the upper part 2 of the housing to be lifted offthe lower part. The actuator mechanism is removed with the part2 and carries with it the ball 9 and seating arrangements 12 and 13. Once clearofthe lower part 3, the whole assembly can be maintained, or replaced by a similar unit.

It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention. For example, jacking screws may be provided between adjacent parts 2 and 3 of the housing to facilitate separation of the parts.

Such an arrangement is shown in Figure 2 where one jacking screw is partially shown referenced 40. The arrangement of Figure 2 has a different disposition of secondary graphite seals 42 in the gland surrounding the mechanism 20. In other respects, the arrangement is the same orsimilartothe arrangement of Figure 1.

1. A ball valve comprising a valve housing defining an inlet and an outlet, a valve ball disposed within the housing between the inlet and the outlet and movable between a first position in which fluid flow between inlet and outlet is prevented and a second position in which fluid flow between inlet and outlet is permitted, and seat meansforthe ball disposed between the housing and the ball to reduce fluid leakage therebetween, the seat means and the ball being so disposed thatthey may be removed together from the housing.

2. A ball valve as claimed in claim 1, in which the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A ball valve The present invention relates to a ball valve. Ball valves are usually employed to shut off fluid flow through a fluid flow line, and are generally known. One such known valve comprises a ball disposed in a housing which defines a fluid inlet and a fluid outlet. The ball defines a through passage, which in one position is aligned with the inlet and the outlet to permitfluidflowthrough thevalveand in another position disaligned to prevent such fluid flow. Seats are disposed between the ball and the housing to prevent or severely restrict fluid flow between the ball and the adjacent wall ofthe housing. The seats require maintenance to ensure the valve remains in correct operating condition. Access to these seats may be gained by splitting the housing and removing the ball. This access may be restricted and therefore makes maintenance difficult. In certain circumstances for example, the valve may be in a hazardous area, possibly enclosed in concrete and access thereto normally available only by robot. According to the present invention, there is pro vided a ball valve comprising a valve housing defining an inlet and an outlet, a valve ball disposed within the housing between the inlet and the outlet and movable between a first position in which fluid flow between inlet and outlet is prevented and a second position in which fluid flow between inlet and outlet is permitted, and seat means for the ball disposed between the housing and the ball to reducefluid leakagetherebe- tween, the seat means and the ball being so disposed that they may be removed together from the housing. In a preferred embodimentofthe invention,the ball is disposed between two seating arrangements which are both supported in a cage. This cage is in turn supported onashaftwhich forms parts an actuator mechanism. The valve housing comprises two parts and the actuator mechanism extends through one part. When the parts are separated, the actuator mechanism, ball and seating arrangements are withdrawn with one of the parts leaving the ball and seating arrangements projecting from that part to facilitate maintenance. In order that the invention may be more clearly understood, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a cross-section of a ball valve, and Figure 2 shows a viewsimilarto Figure 1 butofa modification of the valve of Figure 1. Referring to the drawing, the ball valve comprises a cast metal housing 1. This housing 1 is split into two parts 2 and 3 which are bolted together by means of pairs of bolts 4 and 5, the line of separation of the parts being indicated at 6. A gasket is disposed between the two parts. The lower part3 ofthe housing defines a fluid inlet7, a fluid outlet8 and a chamberforthe ball9 of valve disposed between the inlet 7 and outlet 8. The ball 9, which defines a th rough fluid bore 10, is disposed within a stainless steel cage 11 which supports two seating arrangements 12 and 13 disposed on opposite sides respectively of the ball 9 to form a self sealing wedge shaped assembly.Each seating arrangement 12, 13 comprises a support 18, 19 formed to accept an annular soft material seat such as a graphited TFE (Tetrafluoroethylene) seat 14, 15, on one side and an annular soft material secondary seat such as a graphited TFE seat 16, 17 on the other. Seats 16 and 17 on the sloping faces of the assembly seat and seal between the housing part 3 and seat supports 18 and '19 respectively and seats 14 and 15 seat and seal between seat supports 18 and 19 and the ball 9. The cage 11 is connected to a shaft 20 which forms part of an actuator mechanism indicated generally by the reference numeral 21. The mechanism 21 aiso comprises an actuator lever 22. The shaft extends through locknuts 23, which fix the lever 22 to the shaft 20, a washer 24, a keep plate 25, a spring adjuster 26, disc springs 27, thrust plate retainer 28, thrust plate 29, stainless steel spring 30, gland rings 31 which incorporate secondary graphite seals 32, stainless steel shims 33 and primary chevron type P.T.F.E. seals 34. The lower end of the shaft informed with a flange 35 on which cage 11 sits and a spigot 36 which extends into a complementary recess in the ball 9. Rotation of the lever22 through one quarterturn rotatesthe ball 9 through shaft 22 between valve open and valve closed positions. When access to the ball valve seat is required for maintenance, bolts 4 and 5 are removed enabling the upper part 2 of the housing to be lifted offthe lower part. The actuator mechanism is removed with the part2 and carries with it the ball 9 and seating arrangements 12 and 13. Once clearofthe lower part 3, the whole assembly can be maintained, or replaced by a similar unit. It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention. For example, jacking screws may be provided between adjacent parts 2 and 3 of the housing to facilitate separation of the parts. Such an arrangement is shown in Figure 2 where one jacking screw is partially shown referenced 40. The arrangement of Figure 2 has a different disposition of secondary graphite seals 42 in the gland surrounding the mechanism 20. In other respects, the arrangement is the same orsimilartothe arrangement of Figure 1. CLAIMS

2. A ball valve as claimed in claim 1, in which the seat means are disposed in a cage.

3. A ball valve as claimed in claim 2, in which the cage is supported on a shaft which forms part of an actuator mechanism.

4. A ball valve as claimed in claim 3, in which the valve housing comprises two parts and the actuator mechanism extends through one part.

5. A ball valve as claimed in claim 4, in which, when the parts are separated, the actuator mechanism, ball and seat means are withdrawn with one of the parts leaving the ball and seat means projecting from the part.

6. A ball valve as claimed in any preceding claim, in which at least one jacking screw is provided to facilitate separation of the parts.

7. A ball valve as claimed in any preceding claim, in which the seat means and ball form a self sealing wedge shape assembly which is disposed in a complementarywedgeshaped cavity inthe housing.

8. A ball valve as claimed in any preceding claim, in which theseatmeans comprisetwo seating arrangements disposed on opposite sides respectively ofthe ball.

9. A ball valve as claimed in claim 8, in which each seating arrangement comprises a supportformed to accept annular soft material seats on opposite sides respectivelythereof, one being operative to seat and seal between the support and the housing and the other being operative to seat and seal being the support and the ball.

10. A ball valve as claimed in claim 9, in which each annular soft material seat comprises graphited tetrafluoroethylene.

11. A ball valve substantially as hereinbefore described with reference to Figure 1 orto Figure 2 of the accompanying drawings.