Extreme temperature, high pressure balanced, rising stem gate valve with super preloaded, stacked, solid lubricated, metal-to-metal seal

• US 4,363,465 A
• Filed: 06/16/1976
• Issued: 12/14/1982
• Est. Priority Date: 06/16/1976
• Status: Expired due to Term

• Current Assignee: Cooper Cameron Corporation (Schlumberger NV)
• Original Assignee: Smith International Incorporated (Schlumberger NV)
• Inventors: Morrill, Charles D.
• Primary Examiner(s): Walton, George L.
• Application Number:
  US05/697,084
• Time in Patent Office: 2,372 Days
• US Class Current: 251/214
• CPC Class Codes: F16K 41/04 with at least one ring of rubber or like material between spindle and housing
• CPC Class Codes: Y10T 137/4372 Line pressure feed

Abstract

A balanced high pressure rising stem gate valve has lubricated metal-to-metal seal means between the bonnet part of the valve body and the valve actuating stem and between the chamber part of the valve body and the balancing stem. Each seal means includes plural, e.g. three dished elastic metal ring gaskets with a high temperature resistant and chemical resistant ring of solid lubricant, tetrafluoroethylene or graphite between each adjacent pair of metal gaskets. Each metal gasket is softer than the stem and is of rectangular cross-section and the edge at the inner periphery on the concave side is rounded. Each seal means is disposed in an annular pocket in the adjacent part of the valve body extending around the stem. Each pocket is closed by an annular plug screwed into the pocket far enough to flatten out the dished metal rings sufficiently for the inner and outer peripheries of each ring to engage the stem and pocket respectively with enough pressure to cause plastic deformation of the inner peripheral edge on the concave side and the outer peripheral edge on the convex side, and to deform the elastic solid lubricant rings into engagement with the stem and pocket, and to prevent movement of the seal relative to the pocket when the valve is in use despite variations in the temperature of the valve and the pressure of the fluid therein and thereabout. The valve stem sealing arrangement may also be employed for packing off lock screws and in other situations wherein relatively movable parts are to be sealed both during and after relative motion.

Claims

1. A Valve including a hollow body having a flow path therethrough, balanced rising stem gate means in the body reciprocal to control fluid flow through the body and including actuator and balance stems extending through ports in the body from the inside thereof, there being an annular pocket having a wall in the body around each stem, each of said walls being substantially parallel to the corresponding one of said stems, seal means in each pocket, and plug means engageable with each seal means for compressing said seal means, each seal means including at least one dished metal ring gasket and one sandwich ring adjacent thereto made of a more compliant material, each of said dished metal ring gaskets being deformed at its peripheral edges into metal-to-metal sealing engagement with the corresponding one of said stems and said walls upon compression of said seal means by said plug means.

2. Valve according to claim 1 in which the sandwich ring is made of lubricating material.

3. Valve according to claim 2 in which the sandwich ring is an elastomer.

4. Valve according to claim 3 in which the sandwich ring is made of "Teflon".

5. Valve according to claim 4 in which the sandwich ring material includes up to 15 percent of molybdenum sulfide.

6. Valve according to claim 5 including a second sandwich ring made of "Grafoil".

7. Valve according to claim 3 in which the sandwich ring has an unloaded diametral interference with the stem of several thousandths of an inch, e.g. 2 or more.

8. Valve according to claim 3 in which the sandwich ring is initially of a different cross section from its cross section when the seal means is compressed.

9. Valve according to claim 8 in which the sandwich ring is initially of rectangular cross section.

10. Valve according to claim 9 in which the sandwich ring when loaded is of parallelogram diamond cross section with internal angles different from 90 degrees.

11. Valve according to claim 1 in which the metal ring gasket is of rectangular cross section and rounded at the inner peripheral edge on the concave side.

12. Valve according to claim 1 in which the metal ring gasket is compressed to be partially flattened out and its inner and outer peripheries are coined where they engage the stem and pocket.

13. Valve according to claim 12 wherein the stem and pocket side are cylindrical surfaces.

14. Valve according to claim 1 in which the metal ring gaskets are frusto-conical and the adjacent faces of the plug and pocket bottom are provided with surface means for engaging said seal means of conical configuration but having greater cone angles than said metal ring gaskets.

15. Valve according to claim 14 wherein at least one of said surface means is integral with one of said adjacent faces of the plug means and pocket bottom.

16. Valve according to claim 14 wherein at least one of said surface means is provided by an adapter ring.

17. Valve according to claim 14 wherein both of said surface means are provided by adapter rings.

18. Valve according to claim 1, each seal means including a second metal ring gasket with the sandwich ring disposed between the gaskets.

19. Valve according to claim 18 in which both gaskets are dished in the same direction.

20. Valve according to claim 19, each seal means including a third gasket dished in the same direction and a second sandwich ring between the second and third gaskets.

21. Valve according to claim 20 in which said gaskets are dished toward the valve pressure to be sealed against.

22. Valve according to claim 21 in which the seal means is super preloaded.

23. A sealing system for a high pressure valve including a valve body having inlet and outlet conduits and upper and lower apertures with a chamber therebetween, a bonnet closing the upper aperture, a cap closing the lower aperture, an upper stem and a lower stem mounted within the valve body and having a gate disposed therebetween, a gate seat disposed within the chamber and housing the gate, the upper stem extending into the bonnet, the lower stem extending into the cap, and the valve having an open position where the gate permits flow through the conduits and a closed position where the gate blocks flow through the conduits, the improvements comprising:

first dual seal means providing at least two separate means for providing metal-to-metal sealing engagement between the upper stem and the bonnet, one of said separate means of said first dual seal means including at least one dished metal ring gasket deformed at its peripheral edges into such metal-to-metal sealing engagement with both the upper stem and bonnet;

second dual means providing at least two separate means for providing metal-to-metal sealing engagement between the lower stem and the valve body, one of said separate means of said second dual means including at least one dished metal ring gasket deformed at its peripheral edges into such metal-to-metal sealing engagement with both the lower stem and valve body.

24. A sealing system for a high pressure gate valve including a valve body having inlet and outlet conduits with a chamber therebetween, an upper stem reciprocably disposed in a bonnet mounted on the valve body, a gate mounted below and attached to the upper stem and reciprocably disposed in a gate seat mounted within the chamber and a reciprocating apparatus for moving the gate between a closed position where flow is blocked through the conduits and an open position where flow is permitted through the conduits, the improvement comprising:

first seal means for providing a metal-to-metal sealing engagement between the upper stem and the bonnet, said first seal means including at least one dished metal ring gasket deformed at its peripheral edges into such metal-to-metal sealing engagement with both the upper stem and bonnet;

and second seal means for providing a metal-to-metal sealing engagement between the upper stem and the bonnet in the open position, said second seal means including an annular enlargement portion on said upper stem engageable with an annular seat in said bonnet when such valve is in such open position.

25. A valve including a hollow body having a flow path therethrough and a port therethrough, rising stem gate means in the body reciprocable to control fluid flow through the body and including an actuator and a stem extending through the port in the body from the inside thereof, there being an annular pocket in the body around the stem, the pocket having a wall, said wall being substantially parallel to said stem, seal means in the pocket, and a packing gland engageable with the seal means for compressing the seal means, the seal means including at least one dished metal ring gasket and one sandwich ring adjacent thereto made of a more compliant material than the metal ring gasket, said dished metal ring gasket being deformed at its peripheral edges into metal-to-metal sealing engagement with said stem and said wall upon compression of said seal means by said packing gland.

26. A valve including a hollow body having a flow path therethrough and a port, stem gate means in the body for controlling fluid flow through the body and including a stem extending through the port in the body from the inside thereof, there being an annular pocket in the body around the stem, seal means in the pocket for preventing fluid from flowing from the body through the annular pocket, and compression means engageable with the seal means for compressing the seal means, the seal means including metal ring gaskets and means for urging each of the metal ring gaskets into metal-to-metal sealing engagement with both the stem and the pocket upon compression of the seal means by the compression means, each of said metal ring gaskets being deformed at its peripheral edges where such metal-to-metal sealing engagement is effected.

27. A subassembly of a seal system, the seal system used to prevent a flow of fluid along the wall of a moving stem and along a fixed wall closely positioned to the moving stem and parallel thereto, comprising

a non-extrudable seal ring juxtaposed to and in sealing engagement with both the wall of the moving stem and the fixed wall for preventing such flow of fluid said non-extrudable seal ring being deformed at its peripheral edges into metal-to-metal sealing engagement with said fixed wall and said stem wall;

an extrudable seal ring;

said non-extrudable seal ring being positioned to prevent said extrudable seal ring from extruding under pressure between said non-extrudable seal ring and the wall of the moving stem and between said non-extrudable seal ring and the fixed wall.

28. A seal system between a fixed wall and a wall of a moving component, such walls being substantially parallel to each other, for preventing fluid flow from the fluid side of the seal to the atmospheric side of the seal, comprising:

a sandwich ring;

a metal ring gasket disposed between such fixed wall and such wall of such moving component;

compression means for compressing said sandwich ring and said metal ring gasket and for deforming said metal ring gasket at its peripheral edges into metal-to-metal sealing engagement with both of such walls.