Gauge pressure sensor for hazardous applications

• US 6,715,360 B1
• Filed: 02/19/2003
• Issued: 04/06/2004
• Est. Priority Date: 02/19/2003
• Status: Active Grant

• Current Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Original Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Inventors: Vanderah, Richard J., Sickels, Dennis Gene, Pepperling, Donald Paul
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): JENKINS, JERMAINE L
• Application Number:
  US10/368,697
• Time in Patent Office: 412 Days
• Field of Search: 737/56, 737/00, 737/06
• US Class Current: 73/756
• CPC Class Codes: A62C 4/00 Flame traps allowing passage of gas but not of flame or explosion wave
• CPC Class Codes: G01L 19/0636 using particle filters
• CPC Class Codes: G01L 19/0663 Flame protection; Flame barriers
• CPC Class Codes: G01L 19/0672 Leakage or rupture protection or detection

Abstract

Methods and apparatus for sensing a gauge pressure use a pressure gauge pressure sensor that includes a housing and a gauge pressure sensing element having a first pressure inlet and a second pressure inlet. The first pressure inlet is associated with a pressure to be measured and the second pressure inlet is associated with an atmospheric pressure. A flame arrestor disposed within the sensor housing fluidly couples the second pressure inlet to an internal portion of an explosion proof device.

Claims

1. A pressure sensor for use with an explosion proof device having a chamber, the pressure sensor comprising:

a gauge pressure sensing element having a first pressure inlet and a second pressure inlet, wherein the first pressure inlet is associated with a pressure to be measured and wherein the second pressure inlet is associated with an atmospheric pressure;

a flame arrestor fluidly coupled to the second pressure inlet and;

a housing configured to hold the gauze pressure sensing element and the flame arrestor to fluidly couple the flame arrestor to a second flame arrestor that vents the chamber of the explosion proof device.

2. A sensor as defined in claim 1, wherein the flame arrestor includes a plurality of flame proof electrical connections to the gauge pressure sensing element.

3. A sensor as defined in claim 2, wherein the plurality of electrical connections are glassed-in.

4. A sensor as defined in claim 1, wherein the housing includes a connection configured to accept a combustible process fluid.

5. A sensor as defined in claim 4, wherein the connection includes a threaded engagement.

6. A sensor as defined in claim 1, wherein the pressure sensor includes a stop to retain the pressure sensing element against an explosion pressure.

7. A sensor as defined in claim 1, wherein the flame arrestor is made of sintered metal.

8. A sensor as defined in claim 1, wherein the flame arrestor has a cylindrical geometry.

9. A sensor as defined in claim 1, wherein the gauge pressure sensing element is silicon-based.

10. An explosion proof device, comprising:

a housing having a first flame arrestor that vents an inner chamber of the housing to an atmospheric pressure; and

a pressure sensor assembly including a second flame arrestor and a gauge pressure sensing element having first and second pressure inputs, wherein the first pressure input is fluidly coupled to a port configured to accept a process fluid and the second pressure input is fluidly coupled to the second flame arrestor, and wherein the second flame arrestor is fluidly coupled to the inner chamber.

11. A sensor as defined in claim 10, wherein the second flame arrestor includes a plurality of flame proof electrical connections to the gauge pressure sensing element.

12. A sensor as defined in claim 11, wherein the plurality of flame proof electrical connections are glassed-in.

13. An explosion proof device as defined in claim 10, wherein the explosion proof device is one of a process fluid regulation and a process fluid monitoring device.

14. An explosion proof device as defined in claim 10, wherein the first and second flame arrestors are made of a sintered metal.

15. An explosion proof device as defined in claim 10, wherein the second flame arrestor has a cylindrical geometry.

16. A method of sensing a gauge pressure of a process fluid, comprising:

detecting the gauge pressure of the process fluid at a first opening of a pressure sensor assembly;

venting a second opening of the pressure sensor assembly through a flame arrestor fluidly coupled to a second opening of the pressure sensor assembly into a housing of a process fluid device; and

venting the housing of the process fluid device to an atmospheric pressure through a second flame arrestor.

17. A method as defined in claim 16, wherein the flame arrestor has a cylindrical geometry.

18. A method as defined in claim 16, wherein detecting the gauge pressure of the process fluid includes conveying an electrical signal from the pressure sensor assembly through a flame proof electrical connection that passes through the flame arrestor.