Two-stage seal for a valve

Patent metadata

Field	Value
Publication number	US-9644742-B2
Application number	US-201414185821-A
Country	US
Kind code	B2
Filing date	Feb 20, 2014
Priority date	Mar 15, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A two-stage seal, such as a ring seal for use in a pressurized process fluid line, has a dynamic sealing member and a static sealing member. The dynamic sealing member is arranged to continuously sealingly engage against a seal surface that slides along the dynamic sealing member. The static sealing member is arranged to sealingly engage against the seal surface in response to an increased process fluid pressure within the process fluid line to increase static seal pressure against the seal surface. The static sealing member is also arranged to release from the seal surface to minimize friction with the seal surface when the process fluid pressure drops and/or in response to movement of the seal surface. The two-stage seal may be used in arrangements requiring both dynamic sealing and static sealing, such as in some process control valves. A process control valve having the two-stage seal is disclosed.

First claim

What is claimed:

1. A two-stage seal for forming a static lateral seal and a dynamic lateral seal along a sliding interface between a first sealing surface and a second sealing surface in a pressurized process line, the seal comprising:
a body defining a dynamic seal member and a static seal member, wherein each of the dynamic seal member and the static seal member is arranged to sealingly engage the first sealing surface, the first surface arranged to shift in relation to the body, wherein the body has a profile comprising a base member, wherein the dynamic seal member extends from the base member in a first direction, and wherein the static seal member extends laterally from the base member in a second direction; and
a spring member carried by the body, wherein the spring member is encased within the base member;
wherein the dynamic seal member is arranged to form a dynamic seal with the first sealing surface;
wherein the static seal member is arranged to form a static seal with the first sealing surface in response to an increased pressure in the pressurized process line and is arranged to release the static seal; and
wherein the dynamic seal member functions substantially independently of the static seal member.

2. The two-stage seal of claim 1 , wherein the profile of the body further comprises:
a first seal wall extending from the base member in the first direction, the first seal wall defining the dynamic seal member;
a groove adjacent the base member and adjacent the first seal wall; and
a wiper seal extending laterally from the base member in the second direction, the wiper seal defining the static seal member;
wherein increased fluid pressure in the groove causes the wiper seal to shift laterally in the second direction.

3. The two-stage seal of claim 2 , wherein the base member bows away outwardly from the groove and shifts the wiper seal laterally in the second direction in response to the increased pressure.

4. The two-stage seal of claim 2 , wherein the spring member is carried by the base member and is arranged to urge the wiper seal laterally in a third direction opposite the second direction.

5. The two-stage seal of claim 2 , wherein the spring member forms an arch laterally across the base member, the arch being convex toward the groove.

6. The two-stage seal of claim 1 , wherein the seal comprises a ring seal.

7. A two-stage seal having a profile extending along a longitudinal axis, the profile comprising:
a body defining a base member extending laterally from a first end to a second end, a first seal wall extending upwardly from the first end of the base member, a second seal wall extending upwardly from the second end of the base member, a first wiper seal extending laterally outwardly from the first end of the base member, wherein the base member and the first and second seal walls define a groove opposite the first wiper seal; and
a lateral spring member carried by the base member, the lateral spring member having a second profile extending from the first end to the second end of the base member;
wherein the base member and the lateral spring member urge the wiper seal laterally outwardly toward a static sealing position in response to an increased pressure inside the groove, and wherein the lateral spring member urges the wiper seal laterally inwardly from the static sealing position.

8. The two-stage seal of claim 7 , wherein the wiper seal is offset downwardly from the base member.

9. The two-stage seal of claim 7 , wherein the lateral spring member has an arched profile with a convex side directed upwardly toward the groove.

10. The two-stage seal of claim 7 , wherein the lateral spring member comprises a hinge portion along the profile.

11. The two-stage seal of claim 7 , wherein the body further comprises:
a first support rail projecting downwardly from the base member; and
a second support rail projecting downwardly from the base member;
wherein the base member and the first and second support rails define a cavity.

12. The two-stage seal of claim 11 , wherein the body further comprises:
a bottom wall enclosing the cavity.

13. The two-stage seal of claim 12 , further comprising:
foam disposed inside the cavity.

14. The two-stage seal of claim 12 , wherein the bottom wall extends from the first support rail to the second support rail and seals the cavity.

15. The two-stage seal of claim 7 , wherein the lateral spring member extends continuously along the longitudinal axis.

16. The two-stage seal of claim 7 , wherein the body forms a ring seal, and wherein the body comprises a first material, the lateral spring member comprises a second material, and the second material is stiffer than the first material.

17. A valve assembly for a pressurized process flow line, the valve comprising:
a valve body defining a flow passage extending from an inlet to an outlet;
a flow control member disposed in the flow passage, wherein the flow control member is arranged to shift in relation to a fixed surface along the flow passage to open and close the flow passage; and
a two-stage seal having a seal body and a spring member encased within the seal body, wherein the seal body is arranged to form a dynamic seal and a static seal across an interface between the flow control member and the fixed surface, wherein the seal body is arranged to engage the static seal in response to a pressure spike in the flow passage, and wherein the spring member is arranged to disengage the static seal.

18. The valve assembly of claim 17 , wherein the seal body comprises:
a base member having a first end and a second end, the base member extending laterally across the interface between the flow control member and the fixed surface;
a first seal wall extending from the base member and forming the dynamic seal;
a first wiper seal extending laterally outwardly from the base member and arranged to form the static seal; and
a groove adjacent the base member and the first seal wall;
wherein the spring member is carried by the base member, the spring member extending laterally from the first end to the second end of the base member, and
wherein the base member and the spring member urge the wiper seal laterally outwardly toward a static sealing position between the flow control member and the fixed surface in response to an increased pressure inside the groove, and wherein the lateral spring member urges the wiper seal laterally inwardly from the static sealing position.

19. The valve assembly of claim 18 , wherein the fixed surface comprises a cage, wherein the flow control member comprises a land, and wherein the two-stage seal is disposed inside the land.

20. The valve assembly of claim 17 , wherein the valve assembly comprises a sliding stem valve.

Assignees

• Fisher Controls Int Llc

Inventors

• Linser Mark J

Classifications

• F16K25/02

  Arrangements using fluid issuing from valve members or seats · CPC title

• F16K3/24

  with cylindrical valve members · CPC title

• F16J15/3276

  with additional static sealing between the sealing, or its casing or support, and the surface on which it is mounted · CPC title

• F16K3/267

  Combination of a sliding valve and a lift valve (F16K3/262, F16K3/265 take precedence) · CPC title

• F16J15/164 Primary

  the sealing action depending on movements; pressure difference, temperature or presence of leaking fluid · CPC title