Miniaturized pressure equalized displacement sensor assembly

• US 6,499,368 B2
• Filed: 04/28/1998
• Issued: 12/31/2002
• Est. Priority Date: 01/24/1996
• Status: Expired due to Term

• Current Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Original Assignee: MicroStrain, Inc. (Spectris PLC)
• Inventors: Arms, Steven Willard, Mundell, Steven Ward, Townsend, Christopher Pruyn
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US09/067,710
• Publication Number:
  US 20020117007A1
• Time in Patent Office: 1,708 Days
• Field of Search: 324/207.12, 324/207.18, 324/19, 324/207.24, 324/207.17, 324/207.26, 92/5.R, 731/525.9, 738/665.1, 737/44, 137/553, 137/554, 335/56, 335/59
• US Class Current: 324/207.19
• CPC Class Codes: G01D 11/245 Housings for sensors

Abstract

The novel sensor assembly is comprised of a threaded housing with pressure relief tracks through the threads that terminate at a hole through the housing and a displacement sensor. In the preferred embodiment, we have included an integral connector, a super-elastic core carrier and a Differential Variable Reluctance Transducer. Other sensor types could be used to construct a pressure equalized displacement sensor as described herein, these may include: capacitive, resistive, Hall effect, eddy current, and differential variable transformer.

The sensor is attached to a keyed connector and the entire assembly is potted into the housing. A temperature probe can also be potted with this assembly to allow for multiple tasks t1o be performed by this one housing. The housing is threaded on one end to allow for easy mounting. A hole is drilled through the housing just in back of the sensor and two tracks run perpendicular to and slightly deeper than the threads. The tracks connect to the through hole. This configuration allows fluid to freely flow from the front to the back of the sensor and putting it in equilibrium without escaping from the pressurized environment. This embodiment is hermetically sealed, extremely robust and easily mounted.

Claims

1. A sensor for mounting in a system, comprising:

a sensing device and a housing, said sensing device having a first side and a second side, an aperture in said housing, said sensing device mounted within said aperture;

a first opening in said housing exposing said first side to an environment outside said housing;

a second opening in said housing exposing said second side to said environment outside said housing, wherein said first opening and said second opening provide that pressure on said first side is equal to pressure on said second side of said sensing device; and

said housing further comprising a surface for sealably connecting said housing to the system, said sealing surface to stop fluid flow across said surface.

2. The sensor according to claim 1, wherein said sensing device comprises a differential variable reluctance transducer.

3. The sensor according to claim 1, wherein said sensing device further comprises a super-elastic core carrier.

4. The sensor according to claim 1, wherein said sensing device comprises an electrical connector.

5. The sensor according to claim 1, wherein said housing comprises a hermetic seal.

6. The sensor according to claim 1, wherein said sealing surface comprises a polymer O-ring.

7. The sensor according to claim 1, wherein said sensing device further comprises a spring.

8. The sensor according to claim 1, wherein said sensing device is for measuring displacement.

9. The sensor according to claim 1, wherein said housing comprises an approximately cylindrical unit.

10. The sensor according to claim 1, wherein said first opening comprises said aperture.

11. The device as recited in claim 1, wherein said first opening comprises a hole in said housing.

12. The device as recited in claim 11, wherein said housing comprises an axis and said hole extends along said axis.

13. The sensor according to claim 1, wherein said fastening member comprises a threaded surface.

16. The device as recited in claim 1, wherein said housing comprises stainless steel.

17. The device as recited in claim 1, further comprising a material to seal said sensing device within said housing.

18. The device as recited in claim 1, further comprising a connector to said sensing device.

19. The device as recited in claim 1, wherein said sensing device comprises a displacement sensor.

20. The device as recited in claim 19, wherein said displacement sensor comprises a core carrier tube that can slide freely within said displacement sensor.

21. The device as recited in claim 20, wherein said core carrier tube comprises a magnetically permeable metallic center.

22. The device as recited in claim 20, wherein said core carrier tube comprises a super-eleastic material.

32. The device as recited in claim 13, wherein said second opening comprises a track extending across threads of said threaded surface.

33. The device as recited in claim 13, wherein said housing further comprises a hex head for secure tightening said threaded surface into another threaded surface.

34. The device as recited in claim 32, wherein said second opening further comprises a hole extending from said track to said location.

39. The sensor according to claim 32, wherein said second opening further comprises a hole extending from said track to a location along said aperture that is beyond said sensing device.

14. A threaded member, comprising:

a shaft having a threaded surface and an end surface;

an aperture within said shaft;

a first opening extending from said end surface to said aperture;

a channel extending along said shaft from said end surface and intersecting a plurality of threads of said threaded surface; and

a second opening extending from said channel to said aperture.

15. Threaded member as recited in claim 14, wherein said first opening comprises said aperture.

35. A threaded member as recited in claim 14, wherein a sensor is located within said aperture.

36. A threaded member as recited in claim 14, wherein said shaft comprises an axis and wherein said first opening extends parallel to said axis.

37. A threaded member as recited in claim 36, wherein said first opening extends along said axis.

38. A threaded member as recited in claim 36, wherein said second opening extends perpendicular to said axis.

23. A system, comprising:

a chamber and a sensor for sensing a parameter in said chamber;

said sensor comprising a sensing device and a housing, said sensing device having a first side and a second side, an aperture in said housing, said sensing device mounted within said aperture;

a first opening in said housing exposing said first side to an environment outside said housing;

a second opening in said housing exposing said second side to said environment outside said housing wherein said first opening and said second opening provide that pressure on said first side is equal to pressure on said second side of said sensing device; and

said housing further comprising a surface for sealably connecting said housing to said chamber, said sealing surface to stop fluid flow across said surface.

24. The device as recited in claim 23, wherein said chamber comprises a cylinder.

25. The device as recited in claim 23, wherein said chamber contains a pressurized liquid or gas.

26. The device as recited in claim 25, wherein pressurized liquid or gas can flow freely to said location through said second opening to equalize pressure.

27. The device as recited in claim 23, wherein said sensing device comprises a displacement sensor.

28. The device as recited in claim 27, wherein said displacement sensor comprises a differential variable reluctance transducer.

29. The device as recited in claim 23, wherein said sensing device comprises a connector.

30. The device as recited in claim 23, wherein said sensor is sealed to said chamber.

31. The device as recited in claim 23, wherein said sensing device comprises a spring.