All-metal pressure relief valve

Patent metadata

Field	Value
Publication number	US-10865901-B2
Application number	US-201816185868-A
Country	US
Kind code	B2
Filing date	Nov 9, 2018
Priority date	Nov 9, 2018
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

Abstract

A pressure relief valve having two rigid sealing surfaces lapped to a smoothness Ra of 8 micro-inches or less, and flatness within 80 micro-inches, forms a reliable seal by direct contact therebetween without an elastomer. The sealing surfaces and surrounding structures can be made of one or more metals, such as alloys of stainless steel, and can be CTE-matched, so that the valve is not impeded by environmental temperature changes. In a disclosed embodiment, a “poppet” is axially pressed against a seal plate by a spring. The poppet can be axially stabilized by sliding within a surrounding cylinder or spacer, and can contact the surrounding surface with a plurality of “arms” that reduce friction and enable gas flow therebetween. The poppet can be made from anti-galling Nitronic 60 alloy, and the surrounding structures can be stainless steel. Embodiments are suitable for low-pressure gas applications in extreme environments.

First claim

What is claimed is:

1. A pressure relief valve, comprising:
a fluid inlet and a fluid outlet;
a fixed sealing surface, the fixed sealing surface being fixed in position within a housing; and
a mobile member having a mobile sealing surface positioned in opposition to the fixed sealing surface, the mobile member being axially movable away from and toward the fixed sealing surface so as to alternately separate the sealing surfaces from each other and bring the sealing surfaces into mutual contact with each other;
wherein the mobile member is a poppet that is maintained in axial alignment with the fixed sealing surface by a spacer;
wherein the spacer includes a flange having internal scalloped edges that establish and limit a maximum disance of separation between the sealing surfaces;
wherein the pressure relief valve is closed and prevents passage of a fluid from the fluid inlet to the fluid outlet when the fixed sealing surface and the mobile sealing surface are in direct contact with each other without use of an elastomer therebetween, and the pressure relief valve is open and permits passage of the fluid from the fluid inlet to the fluid outlet when the fixed sealing surface and the mobile sealing surface are separated from each other; and
the pressure relief valve being configured to open when a pressure at the fluid inlet is higher than a pressure at the fluid outlet by more than a specified cracking pressure.

2. The pressure relief valve of claim 1 , wherein each of the sealing surfaces has a roughness Ra that is not greater than 8 micro-inches, and a flatness that is within 80 micro-inches.

3. The pressure relief valve of claim 1 , wherein each of the sealing surfaces has a roughness Ra that is not greater than 4 micro-inches, and a flatness that is within 40 micro-inches.

4. The pressure relief valve of claim 1 , wherein the mobile sealing surface is an annular surface that symmetrically surrounds a central axis of the poppet.

5. The pressure relief valve of claim 1 , wherein the poppet comprises a plurality of arms that extend radially, the arms having distal surfaces that slide along an inner surface of the spacer when the mobile member moves toward and away from the fixed member, whereby the fluid is able to flow between the arms when the pressure relief valve is open.

6. The pressure relief valve of claim 5 , wherein the distal surfaces of the arms have axial edges that are squared in shape.

7. The pressure relief valve of claim 5 , wherein the distal surfaces of the arms have axial edges that are curved in shape.

8. The pressure relief valve of claim 5 , wherein the distal surfaces of the arms are shaped as sections of a sphere.

9. The pressure relief valve of claim 1 , wherein an inner diameter of the flange is variable about a circumference of the flange, thereby reducing obstruction of fluid flow by the flange when the pressure relief valve is open.

10. The pressure relief valve of claim 1 , further comprising a spring configured to apply an axial force to the mobile member that brings the sealing surfaces into mutual contact with each other, a tension of the spring thereby determining the cracking pressure.

11. The pressure relief valve of claim 10 , wherein the spring is a coil spring that is configured to apply a force to the poppet that is symmetrically proximal to a perimeter of the poppet.

12. The pressure relief valve of claim 1 , wherein the fixed sealing surface is formed on a seal plate.

13. The pressure relief valve of claim 12 , wherein the seal plate is in threaded attachment to the housing, and wherein the mobile member is maintained within the housing by the seal plate.

14. The pressure relief valve of claim 13 , wherein threads of the threaded attachment are sealed by a thread sealant.

15. The pressure relief valve of claim 12 , wherein the seal plate, the mobile member, and the housing all have matched thermal coefficients of expansion.

16. The pressure relief valve of claim 12 , wherein the seal plate, the mobile member, and the housing are all made from metal.

17. The pressure relief valve of claim 12 , wherein the seal plate, the mobile member, and the housing are all made from stainless steel.

18. The pressure relief valve of claim 1 , wherein each of the sealing surfaces has a high degree of smoothness and flatness, thereby allowing for relatively frictionless movement.

19. The pressure relief valve of claim 17 , wherein the mobile member is made from an alloy comprising 17% chromium, 8% manganese, 8.5% nickel, 4% sulfur, 0.13% nitrogen, 0.1% carbon, and iron.

20. A method of manufacturing a pressure relief valve that forms a seal by mutual contact between rigid sealing surfaces, the method comprising:
providing a seal plate having a fixed sealing surface and a mobile member having a mobile sealing surface;
smoothing and flattening each of the sealing surfaces; and assembling the seal plate and mobile member into a housing such that:
the mobile sealing surface is positioned in opposition to the fixed sealing surface, the mobile member being axially movable away from and toward the seal plate so as to alternately separate the sealing surfaces from each other and bring the sealing surfaces into direct contact with each other without use of an elastomer therebetween wherein the mobile member is a poppet that is maintained in axial alignment with the fixed sealing surface by a spacer having a flange with internal scalloped edges that establish and limit a maximum distance of separation between the sealing surfaces;

the pressure relief valve is closed and prevents passage of a fluid from an inlet to an outlet when the sealing surfaces are in direct contact with each other without use of an elastomer therebetween, and the pressure relief valve is open and permits passage of the fluid from the inlet to the outlet when the sealing surfaces are separated from each other; and
the pressure relief valve is configured to open when a pressure at the inlet is higher than a pressure at the outlet by more than a specified cracking pressure.

21. The method of claim 20 , wherein smoothing and flattening each of the sealing surfaces includes smoothing and flattening each of the sealing surfaces until each of the sealing surfaces has a roughness Ra that is not greater than 8 micro-inches and a flatness that is within 80 micro-inches.

22. The method of claim 20 , wherein smoothing and flattening each of the sealing surfaces includes smoothing and flattening each of the sealing surfaces until each of the sealing surfaces has a roughness Ra that is not greater than 4 micro-inches and a flatness that is within 40 micro-inches.

23. The method of claim 20 , wherein smoothing and flattening each of the sealing surfaces includes lapping each of the sealing surfaces.

24. A pressure relief valve, comprising:
a fluid inlet and a fluid outlet;
a seal plate having a seal plate sealing surface, the seal plate being fixed in position within a housing; and
a poppet having a mobile sealing surface positioned in opposition to the seal plate sealing surface, the poppet being axially movable away from and toward the seal plate so as to alternately separate the sealing surfaces from each other and bring the sealing surfaces into mutual contact with each other;
wherein the mobile member is a poppet that is maintained in axial alignment with the fixed sealing surface by a spacer;
wherein the spacer includes a flange having scalloped

Assignees

• Bae Sys Inf & Elect Sys Integ

Inventors

• Cleveland Kenneth D
• Colosimo Joseph A
• Patrick Michael J
• Talbourdet John A

Classifications

• F16K25/005

  Particular materials for seats or closure elements · CPC title

• F16K17/0413 Primary

  in the form of closure plates · CPC title

• F16K17/0426

  with seat protecting means · CPC title

• F16K15/147

  the closure elements having specially formed slits or being of an elongated easily collapsible form · CPC title

• F16K17/08

  with special arrangements for providing a large discharge passage · CPC title