GB2135026A

GB2135026A - Valves

Info

Publication number: GB2135026A
Application number: GB08403339A
Authority: GB
Inventors: Raymond Jean Monrocq
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-02-15
Filing date: 1984-02-08
Publication date: 1984-08-22
Also published as: CH655558B; IT1178840B; GB2135026B; IT8467077A0; GB8403339D0; FR2540957A1; FR2540957B1

Abstract

A valve, notably for use with cryogenic fluids, of the type comprising a ball joint interposed between the end of the control stem and the movable valve member, is characterised in that it comprises a spring (34) to compensate for wear of the ball joint, operating under load, and interposed between the lower part (20') of the control stem (20) and the movable member (18), such that the control stem is always held in contact with the movable member. <IMAGE>

Description

SPECIFICATION Improvements in valves The present invention relates to improvements in valves capable of being used with all gaseous and liquid fluids and it is applicable more particularly to valves for very low temperatures, carrying cryogenic fluids such as, liquid nitrogen or helium, for example for applications in the field of nuclear energy or that of aerospace.

There exist valves in which the movable valve part is mounted on a ball joint. In this respect reference may be made to French Patent 1536167, filed on 29th February 1 968 by the present applicant, which describes a valve in which the ball joint is made in the form of a ball interposed between the movable valve member and the lower end of the control stem which makes contact, by a shoulder, with a cover on which is mounted the movable member of the valve. The present invention is intended to provide improvements in this type of valve, alleviating certain disadvantages encountered when using such valves.

In fact, in ball joint valves of the type according to the French Patent mentioned above, the ball generally makes contact with a stainless steel member provided in the lower part of the control stem of the valve, which entails wear of this ball and play, during opening and closing of the movable valve member, which is reflected in modification of the position of the movable valve member relative to the body of the valve. This modification produces variations in the flow characteristics of the valve, which cannot be tolerated in the applications mentioned above.

This invention therefore has as its object a valve of the type mentioned above, that is to say comprising a ball interposed between the end of the control stem and the movable member, characterised in that it comprises a spring to compensate for wear of the ball, operating under load, interposed between the lower part of the control stem and the movable member, such that the control stem is held always in contact with the cover on which the moving valve member is mounted.

The description given below with reference to the accompanying drawing illustrates an embodiment which does not have any limiting character. The single Figure of the drawing is a view in vertical section and elevation of a valve according to the invention.

In known manner, this valve comprises a body' 10 provided with an input duct 1 2 and an output duct 14 for fluid, and a seating 1 6.

This seating cooperates with a movable valve member, indicated in its entirety by reference 18, which is actuated by a control stem 20.

The movable member comprises a needle 22, mounted on a member-carrier 24 on which is screwed a cover 26 in which is engaged a stud 28, provided at the end of the control stem 20. Between the stud 28 and the member-carrier 24 is interposed a ball 30, serving to apply the movable member against its seat, in a manner described in French Patent 1563167 mentioned above.

The lower part of the stud 28 is provided with a plate of stainless steel 32, with which the ball 30 makes contact. It will be seen that at this level wear of the ball takes place, which generates play, during opening and/or closing of the moving valve member, which is due to the fact that the stud 28 and the cover 26 are not applied one against the other, at the emplacement A of their contact surfaces.

To alleviate this difficulty there is interposed a compression spring 34, operating under load, between the lower part 20' of the control stem 20 and the member-carrier 24; this spring, which urges the control stem 20 upwards and the member-carrier 24 (and the cover 26) downwardly suppresses the play mentioned above by holding the stud 28 and the cap 26 in contact with each other at the level A of their contact surfaces.

This arrangement, ensures automatic compensation for wear of the ball 30 and allows obtaining of the same position of the moving needle 22 in its bore at all times on opening of the valve, which ensures an unchanged flow characteristic, whatever the wear of the ball.

The invention is not of course limited to the embodiment herein described but includes all possible variants.

1. Valve, notably for controlling flow of cryogenic fluids, of the type comprising a ball joint interposed between the end of the control stem and the movable valve member, characterised in that it comprises a spring (34) for compensating for wear of the ball joint, operating under load, interposed between the lower part (20') of the control stem (20) and the movable valve member (18), such that the control stem is held always in contact with the movable valve member.

2. Valve according to claim 1, in which the ball joint is provided in the form of a ball 30, with which a stud (28) provided at the end of the control stem makes contact, characterised in that said spring (34) makes contact, on the one hand, with the lower part (20') of the control stem and, on the other hand, with a member-carrier (24) such that said stud (28) and the cover (26) on which the member-carrier (24) is mounted are always applied against each other, at the level of their contact surfaces (A).

3. A valve comprising a movable valve member for controlling flow of fluid through the valve, a control stem for controlling the position of the movable valve member, a ball

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in valves The present invention relates to improvements in valves capable of being used with all gaseous and liquid fluids and it is applicable more particularly to valves for very low temperatures, carrying cryogenic fluids such as, liquid nitrogen or helium, for example for applications in the field of nuclear energy or that of aerospace. There exist valves in which the movable valve part is mounted on a ball joint. In this respect reference may be made to French Patent 1536167, filed on 29th February 1 968 by the present applicant, which describes a valve in which the ball joint is made in the form of a ball interposed between the movable valve member and the lower end of the control stem which makes contact, by a shoulder, with a cover on which is mounted the movable member of the valve. The present invention is intended to provide improvements in this type of valve, alleviating certain disadvantages encountered when using such valves. In fact, in ball joint valves of the type according to the French Patent mentioned above, the ball generally makes contact with a stainless steel member provided in the lower part of the control stem of the valve, which entails wear of this ball and play, during opening and closing of the movable valve member, which is reflected in modification of the position of the movable valve member relative to the body of the valve. This modification produces variations in the flow characteristics of the valve, which cannot be tolerated in the applications mentioned above. This invention therefore has as its object a valve of the type mentioned above, that is to say comprising a ball interposed between the end of the control stem and the movable member, characterised in that it comprises a spring to compensate for wear of the ball, operating under load, interposed between the lower part of the control stem and the movable member, such that the control stem is held always in contact with the cover on which the moving valve member is mounted. The description given below with reference to the accompanying drawing illustrates an embodiment which does not have any limiting character. The single Figure of the drawing is a view in vertical section and elevation of a valve according to the invention. In known manner, this valve comprises a body' 10 provided with an input duct 1 2 and an output duct 14 for fluid, and a seating 1 6. This seating cooperates with a movable valve member, indicated in its entirety by reference 18, which is actuated by a control stem 20. The movable member comprises a needle 22, mounted on a member-carrier 24 on which is screwed a cover 26 in which is engaged a stud 28, provided at the end of the control stem 20. Between the stud 28 and the member-carrier 24 is interposed a ball 30, serving to apply the movable member against its seat, in a manner described in French Patent 1563167 mentioned above. The lower part of the stud 28 is provided with a plate of stainless steel 32, with which the ball 30 makes contact. It will be seen that at this level wear of the ball takes place, which generates play, during opening and/or closing of the moving valve member, which is due to the fact that the stud 28 and the cover 26 are not applied one against the other, at the emplacement A of their contact surfaces. To alleviate this difficulty there is interposed a compression spring 34, operating under load, between the lower part 20' of the control stem 20 and the member-carrier 24; this spring, which urges the control stem 20 upwards and the member-carrier 24 (and the cover 26) downwardly suppresses the play mentioned above by holding the stud 28 and the cap 26 in contact with each other at the level A of their contact surfaces. This arrangement, ensures automatic compensation for wear of the ball 30 and allows obtaining of the same position of the moving needle 22 in its bore at all times on opening of the valve, which ensures an unchanged flow characteristic, whatever the wear of the ball. The invention is not of course limited to the embodiment herein described but includes all possible variants. CLAIMS

3. A valve comprising a movable valve member for controlling flow of fluid through the valve, a control stem for controlling the position of the movable valve member, a ball between the movable valve member and an end of the control stem for transmitting thrust therebetween and a spring urging surfaces of the movable valve member and the control stem together.

4. A valve according to claim 3, in which the movable valve member comprises a carrier for carrying means to open and close the valve and the spring is under compression and engages an end of the control stem and the carrying member.

5. A valve according to claim 4 in which a cover is mounted on the carrying member and an end of the stem is provided with a stud which makes contact with the ball positioned inside the cover, the spring urging the stud against a surface of the cover.

6. A valve, substantially as hereinbefore described with reference to the accompanying drawings.