PRESSURE RELIEF DEVICE INTEGRITY SENSOR

• US 20120319857A1
• Filed: 07/30/2010
• Published: 12/20/2012
• Est. Priority Date: 07/31/2009
• Status: Active Grant

• Current Assignee: Geof Brazier, Hughie Leahy, John Tomasko, Liam Fitzgerald, Stephen Farwell
• Original Assignee: Geof Brazier, Hughie Leahy, John Tomasko, Liam Fitzgerald, Stephen Farwell
• Inventors: Brazier, Geof, Farwell, Stephen, Tomasko, John, Fitzgerald, Liam, Leahy, Hughie
• Granted Patent: US 10,139,005 B2
• Time in Patent Office: Days
• US Class Current: 340/679
• CPC Class Codes: F16K 17/16 with fracturing diaphragm ; Rupture discs
• CPC Class Codes: F16K 37/00 Special means in or on valves or other cut-off apparatus for indicating or recording operation thereof, or for enabling an alarm to be given
• CPC Class Codes: F16K 37/0083 by measuring valve parameters
• CPC Class Codes: Y10T 137/1789 Having pressure responsive valve
• CPC Class Codes: Y10T 137/8158 With indicator, register, recorder, alarm or inspection means

Abstract

A sensor for sensing the integrity of a pressure relief device, along with associated systems and methods, are disclosed. The sensor may sense a designed area of weakness of a pressure relief device, such as an explosion vent or rupture disk. A monitor may monitor a signal from the sensor, which may be transmitted between the sensor and monitor by way of a sensor loop. In response to a change in the designed area of weakness, the signal from the sensor may be altered or interrupted, indicating that the designed area of weakness has changed. The signal from the sensor may be, for example, an electrical signal, optical signal, or an air flow in a pneumatic loop.

Claims

1. A pressure relief device integrity sensor, comprising:

a sensor element configured to sense a condition of a pre-activation reactive region of a pressure relief device, the sensor element configured to transmit a signal indicative of a normal condition;

wherein a change in or interruption of the signal indicates a change in the pre-activation reactive region.

2. The pressure relief device integrity sensor of claim 1, wherein the change in the pre-activation reactive region is detected before activation of the pressure relief device.

3. The pressure relief device integrity sensor of claim 1, wherein the sensor element is configured to be attached to the pre-activation reactive region.

4. The pressure relief device integrity sensor of claim 1, further comprising:

a monitor; and

a sensor loop transmitting the signal between the sensor element and the monitor.

5. The pressure relief device integrity sensor of claim 4, wherein the sensor loop and sensor element comprise a normally closed circuit, and wherein the normally closed circuit is configured to open in response to a change in the pre-activation reactive region.

6. The pressure relief device integrity sensor of claim 1, wherein the sensor element comprises a conductive element exhibiting a first resistance.

7. The pressure relief device integrity sensor of claim 6, wherein the conductive element is configured to deform in response to a change in the pre-activation reactive region, and wherein deformation of the conductive element causes the conductive element to exhibit a second resistance.

8. The pressure relief device integrity sensor of claim 7, wherein the deformable conductive element is a strain gage.

9. The pressure relief device integrity sensor of claim 1, wherein the sensor element comprises at least one frangible fracture member.

10. The pressure relief device integrity sensor of claim 1, wherein the sensor element comprises a wire.

11. The pressure relief device integrity sensor of claim 1, wherein the sensor element is selected from the group consisting essentially of an optical measuring device, a radio wave device, and a vibration detector.

12. The pressure relief device integrity sensor of claim 4, wherein the sensor loop comprises a pneumatic tube.

13. The pressure relief device integrity sensor of claim 12, wherein the signal comprises an air flow.

14. The pressure relief device integrity sensor of claim 12, wherein the signal comprises a pressure in the pneumatic tube.

15. A pressure relief device integrity sensor, comprising:

a normally closed circuit;

wherein the normally closed circuit is configured to deform in response to a non-activating change in at least one pre-activation reactive region of a pressure relief device.

16. The pressure relief device integrity sensor of claim 15, wherein the normally closed circuit is configured to attach across the at least one pre-activation reactive region.

17. The pressure relief device integrity sensor of claim 16, wherein the normally closed circuit comprises a conductive element, wherein the conductive element is configured to break in response to the non-activating change in the at least one pre-activation reactive region.

18. The pressure relief device integrity sensor of claim 17, wherein the conductive element comprises a frangible fracture member.

19. The pressure relief device integrity sensor of claim 17, wherein the conductive element comprises a wire.

20. The pressure relief device integrity sensor of claim 17, further comprising a tab, wherein the conductive element is configured to impinge on the tab in response to the non-activating change in the at least one pre-activation reactive region.

21. The pressure relief device integrity sensor of claim 16, wherein the normally closed circuit comprises a pneumatic circuit.

22. A system for sensing the integrity of a pressure relief device, comprising:

a pressure relief device having one or more pre-activation reactive regions; and

at least one sensor element configured to transmit a signal indicating a condition of at least one of the one or more pre-activation reactive regions before the pressure relief device activates.

23. The system of claim 22, further comprising:

a monitor configured to monitor the signal from the sensor element; and

a sensor loop configured to transmit the signal between the sensor element and the monitor.

24. The system of claim 23, wherein the sensor loop comprises a normally closed circuit.

25. The system of claim 24, wherein the normally closed circuit is configured to open in response to a change in the pre-activation reactive region.

26. The system of claim 25, wherein the normally closed circuit comprises an electrical circuit.

27. The system of claim 26, wherein the sensor element comprises a frangible member.

28. The system of claim 25, wherein the normally closed circuit comprises an optical circuit.

29. The system of claim 25, wherein the normally closed circuit comprises a pneumatic loop.

30. A method of monitoring a pressure relief device, comprising:

sensing a condition of a pre-activation reactive region of the pressure relief device; and

transmitting a signal indicative of a condition of the pressure relief device.

31. The method of claim 30, wherein sensing a condition of a pre-activation reactive region further comprises sensing a non-activating deformation of the pre-activation reactive region.

32. The method of claim 31, further comprising:

triggering an alarm when the signal indicates that a condition of the pressure relief device has changed without activation of the pressure relief device.

33. The method of claim 32, further comprising:

changing the signal to indicate a change in a physical condition of the pre-activation reactive region; and

wherein triggering an alarm further comprises triggering an alarm when the signal is changed.

34. The method of claim 30, wherein the signal comprises an electrical signal having a current, the method further comprising:

changing the current in response to a change in the pre-activation reactive region.

35. The method of claim 30, wherein the signal comprises an electrical signal having a voltage, the method further comprising:

changing the voltage in response to a change in the pre-activation reactive region.

36. The method of claim 30, wherein the signal comprises an air pressure, the method further comprising:

changing the air pressure in response to a change in the pre-activation reactive region.

37. The method of claim 30, further comprising:

interrupting the signal in response to a change in the pre-activation reactive region.

38. The method of claim 37, further comprising:

triggering an alarm when the signal is interrupted.

39. A pressure relief apparatus for a pressurized system comprising:

a pressure relief device comprising an activating portion configured to relieve pressure when pressure in the pressurized system exceeds a threshold, wherein the activating portion comprises a designed area of weakness and a pre-activation reactive region; and

an integrity sensor configured to sense the integrity of the pressure relief device before activation.

40. The apparatus of claim 39, wherein the designed area of weakness comprises a score line.

41. The apparatus of claim 39 wherein the designed area of weakness comprises a first score line and a second score line, wherein:

the first score line and second score line define an angle between them; and

the pre-activation reactive region is defined within the angle between the first and second score lines.

42. The apparatus of claim 41, wherein the integrity sensor is attached to the activating portion at the pre-activation reactive region.

43. The apparatus of claim 42, wherein the pre-activation region is defined on a line bisecting the angle between the first and second score lines.

44. The apparatus of claim 39, wherein the pre-activation reactive region overlaps with the defined area of weakness.

45. The apparatus of claim 39, wherein the pre-activation reactive region is defined adjacent to the defined area of weakness.

46. The pressure relief device of claim 40, wherein the score line defines an arctuate shape surrounding at least a portion of the activating portion.

47. The pressure relief device of claim 46, wherein activating portion further comprises an indentation.

48. The pressure relief device of claim 47, wherein the arctuate shape comprises a first end and a second end, wherein:

the pressure relief device further comprises a hinge area between the first end and second end of the arctuate shape;

the hinge area and the indentation define a line; and

the pre-activation reactive region is defined on the line on the opposite side of the indentation from the hinge area.

49. The pressure relief device of claim 48, wherein the integrity sensor is positioned adjacent to the pre-activation region.

50. A method of monitoring the integrity of a pressure relief device having a pre-activation reactive region, wherein the pressure relief device is installed with a pressurized system, comprising:

sensing a strain at the pre-activation reactive region; and

generating a signal when the strain indicates that the pressure relief device has been deformed without activating.

51. The method of claim 50, further comprising:

sensing a pressure of the pressurized system;

wherein strain is sensed as a magnitude of strain; and

wherein generating a signal further comprises generating a signal when the level of strain exceeds an allowable threshold level of strain at the sensed pressure.

52. The method of claim 50, further comprising:

sensing the pressure of the pressurized system;

calculating a rate of change of strain per unit of pressure; and

wherein generating a signal further comprises generating a signal when the rate of change of strain per unit of pressure exceeds an allowable threshold.

53. The method of claim 50, further comprising:

calculating a rate of change of strain per unit of time; and

wherein generating a signal further comprises generating a signal when the rate of change of strain per unit of time exceeds an allowable threshold level at a magnitude of strain.

54. A method of monitoring the integrity of a pressure relief device, comprising:

applying a pressure to the pressure relief device;

measuring a strain of at least one region of the pressure relief device;

identifying a pre-activation reactive region based on the strain measured at the at least one region of the pressure relief device; and

monitoring a deformation of the pre-activation reactive region.

55. The method of claim 54, further comprising:

identifying at least one magnitude of strain that indicates the pressure relief device may be compromised.

56. The method of claim 55, wherein identifying at least one magnitude of strain comprises identifying a maximum safe allowable magnitude of strain.

57. The method of claim 54, wherein applying a pressure to the pressure relief device further comprises applying a plurality of pressures to the pressure relief device, and wherein measuring the strain of the at least one region of the pressure relief device further comprises measuring the strain at each of the plurality of pressures, the method further comprising:

identifying at least one rate of strain per unit of time that indicates the pressure relief device may be compromised.

58. The method of claim 57, wherein identifying at least one rate of strain per unit of time comprises identifying a maximum safe allowable rate of strain per unit of time.

59. The method of claim 58, wherein identifying a maximum safe allowable rate of strain further comprises identifying a maximum safe allowable rate of strain per unit of time at a given magnitude of strain.

60. The method of claim 54, wherein applying a pressure to the pressure relief device further comprises applying a plurality of pressures to the pressure relief device, and wherein measuring the strain of the at least one region of the pressure relief device further comprises measuring the strain at each of the plurality of pressures, the method further comprising:

identifying at least one strain at a threshold level of pressure that indicates the pressure relief device may be compromised.

61. The method of claim 60, wherein identifying at least one strain at a threshold level of pressure comprises identifying a maximum safe allowable strain at a threshold level of pressure.

62. The method of claim 54, further comprising:

applying a sensor to the pre-activation reactive region.

63. The method of claim 54, wherein the pressure relief device is a first pressure relief device, the method further comprising:

identifying a pre-activation region of a second pressure relief device corresponding to the pre-activation region of the first pressure relief device; and

monitoring a deformation of the pre-activation region of the second pressure relief device.

64. The method of claim 63, further comprising:

applying a sensor to the pre-activation reactive region of the second pressure relief device.