Wireless sensor assembly for circumferential monitoring of gas stream properties

• US 6,642,720 B2
• Filed: 07/25/2001
• Issued: 11/04/2003
• Est. Priority Date: 07/25/2001
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: DeLancey, James Peter, Maylotte, Donald Herbert
• Primary Examiner(s): Deb, Anjan K.
• Application Number:
  US09/682,130
• Publication Number:
  US 20030020480A1
• Time in Patent Office: 832 Days
• Field of Search: 324/464, 324/658, 324/519, 324/686, 73/233.1, 73/310.5, 73/280.1, 733/350.4, 416/96.R, 123/676, 340/870.17, 340/870.31, 340/870.37
• US Class Current: 324/464
• CPC Class Codes: G01N 33/0022 using a number of analysing channels

Abstract

A wireless sensor assembly for circumferential monitoring of gas stream properties comprises a drive system attachable to a hot gas path housing. A rake is movably coupled to the drive system for unrestricted circumferential movement. At least one RF sensor is disposed on the rake for generating a signal responsive to the gas stream properties. Circuitry is provided for remotely powering the at least one RF sensor and for remotely detecting the signal.

Claims

1. A wireless sensor assembly for circumferential monitoring of gas stream properties comprising:

a drive system attachable to a hot gas path housing;

a rake movably coupled to said drive system for unrestricted circumferential movement;

at least one RF sensor disposed on said rake for generating a signal responsive to said gas stream properties; and

circuitry for remotely powering said at least one RF sensor and for remotely detecting said signal.

2. A wireless sensor assembly in accordance with claim 1, wherein said wireless sensor assembly is capable of operating at temperatures of greater than about 200°

C.

3. A wireless sensor assembly in accordance with claim 2, wherein said circular drive path mechanism is at least one of a chain or a cable.

4. A wireless sensor assembly in accordance with claim 3, wherein said chain or cable is capable of operating at 1400°

F. (760_°

C.) or greater.

5. A wireless sensor assembly in accordance with claim 3, wherein said chain is made of stainless steel.

6. A wireless sensor assembly in accordance with claim 1, wherein said drive system is a circular drive path mechanism.

7. A wireless sensor assembly in accordance with claim 6, wherein said circular drive path mechanism is a circumferential channel.

8. A wireless sensor assembly in accordance with claim 1, further comprising a prime mover disposed outside said hot gas path and coupled to said drive system for circumferential movement thereof.

9. A wireless sensor assembly in accordance with claim 1, wherein said drive system moves in the range between about 10_°

/minute to about 360_°

/minute.

10. A wireless sensor assembly in accordance with claim 1, wherein said drive system moves in the range between about 48_°

/minute to about 90_°

/minute.

11. A wireless sensor assembly in accordance with claim 1, further including a position detection control mechanism.

12. A wireless sensor assembly in accordance with claim 1, wherein said position detection control mechanism is a timer.

13. A wireless sensor assembly in accordance with claim 1, wherein said rake is a rod.

14. A wireless sensor assembly in accordance with claim 1, wherein said rake is a bifurcated rod.

15. A wireless sensor assembly in accordance with claim 1, wherein said rake is an angled rod.

16. A wireless sensor assembly in accordance with claim 1, wherein said rake is made of a material selected from the group consisting of Hastelloy, a nickel-based alloy and a cobalt-based alloy.

17. A wireless sensor assembly in accordance with claim 1, wherein said drive system further comprises a carriage mount for coupling said rake to said drive system.

18. A wireless sensor assembly in accordance with claim 17, wherein said carriage mount is capable of operating at temperatures greater than 1400°

F.

19. A wireless sensor assembly in accordance with claim 17, wherein said carriage mount positions said rake substantially normal to said hot gas path housing.

20. A wireless sensor assembly in accordance with claim 1, wherein said RF sensor comprises an LC circuit including an induction coil and a capacitor having a dielectric material, which dielectric material has a dielectric constant that is a function of temperature.

21. A wireless sensor assembly in accordance with claim 20, wherein said dielectric is capable of sensing temperatures of at least 900°

F. (482_°

C.).

22. A wireless sensor assembly in accordance with claim 21, wherein said ceramic base is selected from the group consisting of alumina and zirconia.

23. A wireless sensor assembly in accordance with claim 1, wherein said RF sensor is responsive to a frequency of at least 1 MHz.

24. A wireless sensor assembly in accordance with claim 1, wherein said RF sensor is responsive to a frequency in the range between about 200 MHz to about 600 MHz.

25. A wireless sensor in accordance with claim 1, wherein said RF sensor is sensitive to a property selected from the group consisting of temperature, NOx concentration, salt concentration, oxygen concentration, carbon monoxide concentration, carbon dioxide concentration and particulate concentration.

26. A wireless sensor assembly in accordance with claim 1, wherein said RF sensor has a ceramic base.

27. A wireless sensor assembly in accordance with claim 1, wherein said circuitry is a pulsed circuit.

28. A wireless sensor assembly in accordance with claim 1, wherein said circuitry includes a power source, a microprocessor and an RF detector.

29. A wireless sensor assembly in accordance with claim 28, wherein said circuitry further includes a data acquisition device.

30. A wireless sensor assembly in accordance with claim 29, wherein said circuitry includes at least one antenna disposed upon said housing.

31. A wireless sensor assembly in accordance with claim 30, wherein said at least one antenna is two antennas spaced apart by 180°

.

32. A wireless sensor assembly in accordance with claim 31, wherein said at least one antenna generates a signal to power said RF sensor.

33. A wireless sensor assembly in accordance with claim 31, wherein said antenna generates a signal having a bandwidth to cover the range frequencies for each respective RF sensor.

34. A wireless sensor assembly in accordance with claim 31, wherein said antenna generates a signal having a bandwidth with a specific frequency related to a specific RF sensor.

35. A wireless sensor assembly in accordance with claim 31, wherein said antenna sends pulses to said at least one RF sensor.

36. A wireless sensor assembly in accordance with claim 31, wherein said RF detector can discriminate between frequencies to determine which RF sensor is detected.

37. A wireless sensor for circumferential monitoring of gas stream properties within a hot gas path housing, said sensor comprising:

an RF sensor for generating a signal responsive to said gas stream temperature said RF sensor including an induction coil and a capacitor, said capacitor having a dielectric material, which dielectric material has a dielectric constant that is proportional to temperature;

an antenna for generating signals to power said RF sensor;

an RF detector for detecting the signal generated from the RF sensor; and

a microprocessor coupled to said RF detector to correlate the detected signal with the temperature of said gas stream.

38. A method of monitoring gas stream properties within a hot gas path comprising the steps of:

positioning an RF sensor sensitive to a respective gas stream property within said hot gas path for generating a signal responsive to said property;

rotating said RF sensor about said hot gas path housing;

remotely powering said RF sensor;

remotely monitoring said generated signals; and

detecting said generating signals.