VALVE SEALING ARRANGEMENTS AND METHODS

• US 20100090146A1
• Filed: 10/13/2009
• Published: 04/15/2010
• Est. Priority Date: 10/13/2008
• Status: Active Grant

• Current Assignee: Swagelok Company
• Original Assignee: Swagelok Company
• Inventors: Keeper, Branden W., Glime, William H.
• Granted Patent: US 8,490,945 B2
• Time in Patent Office: Days
• US Class Current: 251/172
• CPC Class Codes: F16K 5/188 Sealing effected by the flowing medium
• CPC Class Codes: F16K 5/205 Sealing effected by the flowing medium

Abstract

A valve includes a valve body, a valve element to selectively control flow through the valve, and a seal member and seat member together providing a fluid-tight seal between a valve cavity and a fluid passage in the valve body. A live-loaded biasing member is adapted to apply a live-loaded sealing force to the seat member to bias the seat member toward sealing engagement with the valve element. When the pressure in the fluid passage exceeds the pressure in the valve cavity, an unbalanced passage pressure load biases the seat member toward sealing engagement with the valve element. When the pressure in the valve cavity exceeds the pressure in the fluid passage, an unbalanced cavity pressure load biases the seat member toward sealing engagement with the valve element. The live-loaded sealing force is in parallel with each of the unbalanced passage pressure load and the unbalanced cavity pressure load.

Claims

1. A valve comprising:

a valve body comprising a valve cavity and a fluid passage;

a valve element at least partially disposed in the valve cavity to selectively control flow through the fluid passage;

a seat member at least partially disposed in the fluid passage, the seat member being axially movable along the fluid passage to seal against a sealing surface of the valve element;

a seal member disposed between the seat member and the valve body, the seal member and seat member together providing a fluid-tight seal between the valve cavity and the fluid passage; and

a live-loaded biasing member adapted to apply a live-loaded sealing force to the seat member to bias the seat member toward sealing engagement with the valve element;

wherein when pressure in the fluid passage exceeds pressure in the valve cavity, an unbalanced passage pressure load biases the seat member toward sealing engagement with the valve element, and when the pressure in the valve cavity exceeds the pressure in the fluid passage, an unbalanced cavity pressure load biases the seat member toward sealing engagement with the valve element, the live-loaded sealing force being in parallel with each of the unbalanced passage pressure load and the unbalanced cavity pressure load.

2. The valve of claim 1, wherein the live-loaded biasing member is adapted to apply the live-loaded sealing force to a first bearing surface of the seat member, and the seal member is adapted to apply at least a portion of the unbalanced passage pressure load to a second bearing surface of the seat member, the second bearing surface being separate from the first bearing surface.

3. The valve of claim 2, wherein the seal member is adapted to apply the portion of the unbalanced passage pressure load to the second bearing surface through a force transmitting member axially disposed between the seal member and the seat member.

4. The valve of claim 3, wherein the live-loaded biasing member is configured to apply the live-loaded sealing force to the seat member through the force transmitting member.

5. The valve of claim 3, wherein the force transmitting member extends axially through an opening in the live-loaded biasing member to engage the first bearing surface.

6. The valve of claim 2, wherein the seal member is configured to apply the portion of the unbalanced passage pressure load to the first bearing surface through first and second force transmitting members axially disposed between the seal member and the first bearing surface.

7. The valve of claim 6, wherein the first force transmitting member is provided with a first radial thickness sized to support the seal member, and the second force transmitting member is provided with a second radial thickness sized to accommodate assembly with the live-loaded biasing member.

8. The valve of claim 2, wherein the first bearing surface is axially spaced from the second bearing surface.

9. The valve of claim 2, wherein the first bearing surface is radially spaced from the second bearing surface.

10. The valve of claim 2, wherein the first and second bearing surfaces are coplanar.

11. The valve of claim 2, wherein the first and second bearing surfaces are at least partially radially aligned.

12. The valve of claim 2, wherein the live-loaded biasing member is axially disposed between the first bearing surface and the valve element.

13. The valve of claim 2, wherein one of the first and second bearing surfaces is disposed on a flange portion extending radially from an outer peripheral wall of the seat member, such that the first and second bearing surfaces are axially spaced and at least partially radially aligned with each other.

14. The valve of claim 1, wherein the live-loaded biasing member is axially disposed between the seal member and the valve element.

15. The valve of claim 1, wherein the seal member is axially unbounded by the seat member in a direction away from the valve element.

16. The valve of claim 1, wherein the live-loaded sealing force is isolated from the unbalanced passage pressure load.

17. A valve comprising:

a valve body comprising a valve cavity and a fluid passage;

a valve element at least partially disposed in the valve cavity to selectively control flow through the fluid passage;

a seat member at least partially disposed in the fluid passage, the seat member being axially movable along the fluid passage to seal against a sealing surface of the valve element;

a seal member radially disposed between the seat member and the valve body;

a force transmitting member axially disposed between the seal member and the seat member, the force transmitting member being configured to transmit a first sealing force from the seal member to a first bearing surface on the seat member in response to pressurized fluid applied to the fluid passage to axially bias the seat member towards sealing engagement with the valve element; and

a live-loaded biasing member configured to apply a second sealing force to a second bearing surface on the seat member separate from the first bearing surface, to axially bias the seat member towards sealing engagement with the valve element.

18. The valve of claim 17, wherein the seal member is axially unbounded by the seat member in a direction away from the valve element.

19. The valve of claim 17, wherein the seat member comprises a proximal head portion fixedly retaining a seat ring for sealing against the sealing surface of the valve element, a medial shoulder portion circumferentially stepped down from the head portion, and a distal tail portion circumferentially stepped down from the shoulder portion, with the first bearing surface being disposed on an axially outer face of the shoulder portion, and the second bearing surface being disposed on an axially outer face of the head portion.

20. The valve of claim 17, wherein the first bearing surface is axially and radially spaced from the second bearing surface.

22. The method of claim 20, wherein applying the live-loaded sealing force to the seat member comprises isolating the live-loaded sealing force from the unbalanced passage pressure load.

21. A method of sealing a seat member at least partially disposed in a fluid passage of a valve against a movable valve element at least partially disposed in a valve cavity of the valve, the method comprising:

providing a fluid-tight seal between the fluid passage and the valve cavity;

directing pressurized fluid within the fluid passage such that an unbalanced passage pressure load biases the seat member toward sealing engagement with the valve element when pressure in the fluid passage exceeds pressure in the valve cavity;

directing pressurized fluid within the valve cavity such that an unbalanced cavity pressure load biases the seat member toward sealing engagement with the valve element when pressure in the valve cavity exceeds pressure in the fluid passage; and

applying a live-loaded sealing force to the seat member, the live loaded sealing force being in parallel with each of the unbalanced passage pressure load and the unbalanced cavity pressure load.