Methods and apparatus to monitor diaphragm condition

• US 20080202606A1
• Filed: 02/27/2007
• Published: 08/28/2008
• Est. Priority Date: 02/27/2007
• Status: Abandoned Application

• Current Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Original Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Inventors: Burke, Joseph Michael, O'Hara, Dennis E.
• Application Number:
  US11/711,402
• Publication Number:
  US 20080202606A1
• Time in Patent Office: Days
• US Class Current: 137/551
• CPC Class Codes: F16K 37/0083 by measuring valve parameters
• CPC Class Codes: F16K 7/123 the seat being formed on the bottom of the fluid line
• CPC Class Codes: Y10T 137/8158 With indicator, register, recorder, alarm or inspection means

Abstract

Methods and apparatus are disclosed that monitor a diaphragm condition. In one example, a fluid control device includes a body and a fluid passage through the body, the fluid passage including an inlet and an outlet. The example fluid control device also includes a diaphragm within the fluid control device to control the flow of fluid through the passage, and a sensor coupled to the diaphragm to monitor a condition associated with wear of the diaphragm.

Claims

1. A fluid control device comprising:

a body;

a fluid passage through the body, the fluid passage including an inlet and an outlet;

a diaphragm within the fluid control device to control the flow of fluid through the passage; and

a sensor coupled to the diaphragm to monitor a condition associated with wear of the diaphragm.

2. A fluid control device as defined in claim 1, wherein the condition associated with wear of the diaphragm is at least one of a material condition of the diaphragm or a material condition of the sensor coupled to the diaphragm.

3. A fluid control device as defined in claim 1, wherein the sensor is at least one of mounted to the diaphragm or embedded within the diaphragm.

4. A fluid control device as defined in claim 1, wherein the sensor is at least one of a voltage sensor, a current sensor, a continuity sensor, or a strain gauge.

5. A fluid control device as defined in claim 1, wherein the condition associated with wear of the diaphragm comprises at least one of a durometer, a force, a resistance, a conductance, a voltage, or a current.

6. A fluid control device as defined in claim 1, wherein the sensor is operatively coupled to a controller to calculate signal parameter changes from the sensor.

7. A fluid control device as defined in claim 6, wherein the signal parameter changes comprise at least one of a propagation delay, a frequency, a force, a resistance, or a conductance.

8. A fluid control device as defined in claim 6, wherein the controller comprises a memory to store the signal parameters changes, and wherein the controller is to compare the signal parameter changes to a baseline measurement to determine the condition associated with wear of the diaphragm.

9. A fluid control device as defined in claim 1, wherein the condition of the diaphragm is at least one of new, aged, damaged, critical, or a numerical value indicative of a proximity to a threshold value of the condition associated with wear of the diaphragm.

10. A fluid control device as defined in claim 1, wherein the sensor further comprises at least one of a control unit including a processor, a memory, or an input/output (I/O) port.

11. A fluid control device as defined in claim 1, wherein the diaphragm receives a loading pressure from a process control instrument.

12. A diaphragm as defined in claim 1, wherein the diaphragm is in direct contact with the fluid.

13. A method to determine a diaphragm condition, comprising:

receiving a measured signal from a sensor operatively coupled to a diaphragm;

obtaining a baseline signal; and

comparing the measured signal to the baseline signal to determine the diaphragm condition.

14. A method as defined in claim 13, wherein the measured signal is received when the diaphragm is at least one of in an unactuated position, in a fully actuated position, or in an intermediately actuated position.

15. A method as defined in claim 13, wherein the measured signal is indicative of a voltage, a current, a resistance, a conductance, or a force.

16. A method as defined in claim 13, wherein the baseline signal is measured when the diaphragm is new.

17. A method as defined in claim 13, wherein comparing the measured signal to the baseline signal comprises calculating at least one of a relative difference or an absolute difference between the baseline signal and the measured signal.

18. A method as defined in claim 13, further comprising conveying the diaphragm condition to at least one of a warning indicator or a controller.

19. A method as defined in claim 18, wherein reporting the diaphragm condition comprises storing the measured signal to a memory.

20. A method as defined in claim 13, further comprising comparing the diaphragm condition to a threshold value.

21. A method as defined in claim 20, further comprising providing a warning indicator when the diaphragm condition exceeds the threshold value.

22. A diaphragm for a process control device comprising:

a portion of the diaphragm having a flexible, pressure responsive region; and

a sensor operatively coupled to the pressure responsive region to provide a signal indicative of a physical condition of the pressure responsive region.

23. A diaphragm as defined in claim 22, wherein the sensor is at least one of mounted to the pressure responsive region or located remotely to the pressure responsive region.

24. A diaphragm as defined in claim 23, wherein a control unit is at least one of integral with the sensor or located external to the sensor.

25. A diaphragm as defined in claim 22, wherein the sensor is at least one of a voltage sensor, a current sensor, a continuity sensor, an impedance sensor or a strain gauge.

26. A diaphragm as defined in claim 24, wherein the control unit comprises at least one of a memory, a processor, or an input/output (I/O) port.

27. A diaphragm as defined in claim 24, wherein the control unit is at least one of a personal computer, a microprocessor, or a programmable logic controller (PLC).

28. A diaphragm as defined in claim 22, wherein the pressure responsive region receives a loading pressure from a process control instrument.

29. A diaphragm as defined in claim 22, wherein the pressure responsive region is in direct contact with a process fluid.