Plug valve having a seal boss

• US 7,451,959 B2
• Filed: 12/14/2006
• Issued: 11/18/2008
• Est. Priority Date: 12/14/2006
• Status: Active Grant

• Current Assignee: SPM Oil & Gas Incorporated (Caterpillar Incorporated)
• Original Assignee: SPM Flow Control Inc. (Caterpillar Incorporated)
• Inventors: Matzner, Mark D.
• Primary Examiner(s): Bastianelli; John
• Application Number:
  US11/638,965
• Publication Number:
  US 20080142752A1
• Time in Patent Office: 705 Days
• Field of Search: 251/172, 251/175, 251/192, 251/309, 251/317, 137/375
• US Class Current: 251/192
• CPC Class Codes: F16K 5/0464 in the housing
• CPC Class Codes: Y10T 137/86871 Plug

Abstract

A fluid control valve utilizes a rotatable plug valve member mounted in a fluid passage to control the flow of fluids. Two segments are placed on each side of the plug valve member within a recess located between the plug valve member and the body of the fluid passage. The outer surface of the segments includes an elastomeric seal and metal annular boss, which acts as a stop to limit deformation of the seal when the valve is closed and under pressure.

Claims

1. A fluid control valve comprising:

a body having a flow passage therethrough and a transverse opening therein;

a rotatable plug valve member mounted in the transverse opening for rotation about an axis, the rotatable plug valve member having a port therethrough and being capable of movement between a closed position in which the rotatable plug valve member prevents fluid flow through the flow passage and an opened position in which the port aligns with the flow passage;

a recess in the body located at an intersection of the flow passage and the rotatable plug valve member;

a segment located within the recess, the segments having an inner wall surface in sealing contact with the rotatable plug valve member and an outer wall surface, the segment having a hole whose axis aligns with the flow passage;

a channel located on the outer wall surface of the segment, the channel having two sides and a bottom;

an elastomeric seal located within the channel, the elastomeric seal in sealing engagement with a base of the recess; and

a rigid boss protruding towards the base of the recess from the outer wall surface of the segment adjacent to one side of the channel and adjacent to the hole for contact with the base of the recess adjacent to the point where the elastomeric seal contacts the base of the recess.

2. The fluid control valve of claim 1, wherein the boss comprises a shim.

3. The fluid control valve of claim 1, wherein the boss comprises a coating formed on the segment.

4. The fluid control valve of claim 1, wherein the inner wall surface of the segment and the plug valve member form a metal-to-metal seal.

5. The fluid control valve of claim 1, wherein the boss has a face that is normally spaced from the base of the recess, but which contacts the base of the recess if sufficient fluid pressure exists when the valve is closed.

6. The fluid control valve of claim 1, wherein the boss is annular and encircles the hole in the segment.

7. The fluid control valve of claim 1, wherein the boss is formed of metal.

8. The fluid control valve of claim 1, wherein:

when the plug valve member is in the opened position, the elastomeric seal is deformed into sealing engagement with the base of the recess, and the boss is spaced from the base of the recess by a clearance; and

the thickness of the boss is selected so that under a selected pressure in the flow passage with the plug valve member in the closed position, the boss contacts the base of one of the recess and the elastomeric seal further deforms but still protrudes from the channel.

9. The fluid control valve of claim 1, wherein the elastomeric seal is located a greater distance away from the axis of the hole than the boss.

10. The fluid control valve of claim 1, wherein the inner wall surface of each segment forms a portion of a cylinder.

11. A fluid control valve comprising:

a body having a flow passage therethrough and a transverse opening therein;

a rotatable plug valve member mounted in the transverse opening for rotation about an axis, the rotatable plug valve member having a port therethrough and being capable of movement between a closed position in which the rotatable plug valve member prevents fluid flow through the flow passage and an opened position in which the port of the rotatable plug valve member aligns with the flow passage;

a pair of recesses, each located in the flow passage between the rotatable plug valve member and the body;

two partially cylindrical segments, each located within one of the recesses and having an inner wall surface in contact with the rotatable plug valve member and an outer wall surface adjacent a base of the recess, each segment having a hole whose axis aligns with the flow passage;

a channel located on the outer wall surface of each segment, the channel having two sides and a bottom and surrounding the hole of the segment on which it is located;

a metal annular boss adjacent to the channel, protruding from the outer wall surface of each of the segments towards the base of the recess and surrounding one of the holes, each of the bosses having a face spaced from contact with the base of one of the recesses when the plug valve member is in the opened position;

an elastomeric seal located in the channel on the outer wall surface of each of the segments, each elastomeric seal being located a greater distance from an axis of the hole than the boss and in sealing engagement with the base of one of the recesses; and

the protrusion of each boss being selected such that when under a selected fluid pressure acting on the plug valve member while in the closed position, a downstream one of the elastomeric seals deforms further into its channel and the face of a downstream one of the bosses contacts the base of the recess to limit the deformation of the downstream one of the elastomeric seals.

12. The fluid control valve of claim 11, wherein each of the bosses comprises a shim.

13. The fluid control valve of claim 11, wherein each of the bosses comprises a coating formed on one of the segments.

14. The fluid control valve of claim 11, wherein each of the faces of each of the bosses protrudes from the outer surface of one of the segments a distance in the range of 0.002 inches to 0.003 inches.

15. The fluid control valve of claim 11, wherein the inner wall surface of a downstream one of the segments forms a metal-to-metal seal with the plug valve member.

16. A method of controlling the flow of fluid through a conduit, the method comprising the steps of:

(a) connecting a plug valve into the conduit, the valve comprising a rotatable plug valve member located within a transverse cavity of a body, a downstream segment having an inner wall surface in contact with the rotatable plug valve member, a hole therethrough and an outer wall surface, an elastomeric seal deformed within a channel made up of a bottom and two sides located on the outer wall surface surrounding the hole, the elastomeric seal being in sealing engagement between the outer wall surface and a portion of the body, and a boss located on the outer wall surface of the segments adjacent to the channel;

(b) applying fluid pressure to the plug valve and moving the plug valve member to a closed position, causing a downstream directed force due to the fluid pressure to push the downstream segment in a downstream direction, further deforming the elastomeric seal against the body and causing the boss to contact the body to stop movement of the downstream segment;

then,

(c) opening the plug valve member, thereby causing the elastomeric seal to push the downstream segment in an upstream direction and moving the boss from contact with the body.

17. The method according to claim 16, wherein step (b) further comprises forming a metal-to-metal seal between the inner wall surface of the downstream segment and the plug valve member.