Clearance measurement system and method of operation

• US 20070005294A1
• Filed: 06/27/2005
• Published: 01/04/2007
• Est. Priority Date: 06/27/2005
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (GE Vernova, Inc.)
• Original Assignee: General Electric Company
• Inventors: Jiang, Jie, Andarawis, Emad, Dasgupta, Samhita, Balasubramaniam, Mahadevan, Anderson, Todd, Mani, Shobhana, Shaddock, David
• Granted Patent: US 7,333,913 B2
• Time in Patent Office: Days
• US Class Current: 702/155
• CPC Class Codes: G01B 7/144 Measuring play on bearings

Abstract

A clearance measurement system is provided. The clearance measurement system includes a reference geometry disposed on a first object having an otherwise continuous surface geometry and a sensor disposed on a second object, wherein the sensor is configured to generate a first signal representative of a first sensed parameter from the first object and a second signal representative of a second sensed parameter from the reference geometry. The clearance measurement system also includes a processing unit configured to process the first and second signals to estimate a clearance between the first and second objects based upon a measurement difference between the first and second sensed parameters.

Claims

1. A clearance measurement system, comprising:

a reference geometry disposed on a first object having an otherwise continuous surface geometry;

a sensor disposed on a second object, wherein the sensor is configured to generate a first signal representative of a first sensed parameter from the first object and a second signal representative of a second sensed parameter from the reference geometry; and

a processing unit configured to process the first and second signals to estimate a clearance between the first and second objects based upon a measurement difference between the first and second sensed parameters, wherein the second signal from the reference geometry changes as a function of the clearance between the first and second objects.

2. The system of claim 1, wherein the sensor system is configured to measure the clearance as the first object moves relative to the second object.

3. The system of claim 1, wherein the first object comprises a rotating member and the second object comprises a stationary member disposed about the rotating member in a turbine.

5. The system of claim 1, further comprising:

an excitation source configured to supply excitation signals to the sensor;

a phase detector configured to detect a plurality of reflected signals from respective ones of the first object and the reference geometry and to perform a plurality of phase measurements to determine a phase between each of the reflected signals and the respective excitation signals.

6. The system of claim 1, wherein the sensor is a capacitive probe, and the first and second sensed parameters are capacitances.

7. The system of claim 6, wherein the capacitive probe comprises at least two probe tips for measuring an axial and a radial clearance.

8. The system of claim 1, wherein the reference geometry comprises a recess, or a protrusion disposed on the first object.

9. The system of claim 1, wherein a plurality of reference geometries having dissimilar geometries are disposed on the continuous surface of the first object.

10. The system of claim 9, wherein each of the plurality of reference geometry comprises different depths.

11. The system of claim 1, wherein the reference geometry comprises a multi-level structure.

13. The system of claim 1, further comprising a clearance control unit coupled to the processing unit for controlling the clearance between the first and second objects based upon the clearance estimated by the processing unit.

4. (canceled)

12. The system of clam 1, wherein the processing unit comprises a look-up table, or a calibration curve, or an analytical model, or a calculation, or combinations thereof for estimating the clearance between the first and second objects based upon the measurement difference between the first and second sensed parameters.

14. A rotating machine, comprising:

a rotating component spaced apart from a stationary component, wherein the rotating component comprises a continuous surface in the direction of rotation of the rotating component;

a multi-level reference geometry disposed on the continuous surface of the rotating component;

a sensor configured to generate first and second signals representative of first and second sensed parameters corresponding to the rotating component and different levels of the multi-level reference geometry, respectively; and

a processing unit configured to process the first and second signals to estimate a clearance between the rotating and stationary components based upon a measurement difference between the first and second sensed parameters and pre-determined depths of the different levels of the multi-level reference geometry.

15. The rotating machine of claim 14, wherein the sensor is disposed within the stationary component of the rotating machine.

16. The rotating machine of claim 14, wherein the rotating machine comprises a steam turbine, or a generator, or an electric motor, or a pump, or a compressor.

17. The rotating machine of claim 16, wherein the rotating component comprises a rotating bucket and the stationary component comprises a carrier disposed about the rotating bucket.

18. The rotating machine of claim 14, wherein the sensor comprises a capacitive probe and the first and second sensed parameters comprise capacitances.

27. The rotating machine of claim 14, wherein the second signal representative of the second sensed parameter corresponding to the reference geometry changes as a function of the clearance between the rotating and stationary components.

28. The rotating machine of claim 14, further comprising a plurality of reference geometries having dissimiliar geometries from one another disposed on the continuous surface of the rotating component.

29. The rotating machine of claim 18, wherein the capacitive probe comprises at least two probe tips for measuring an axial and a radial clearance.

19. A method of measuring a clearance between a first object and a second object, comprising:

generating a first signal indicative of a first sensed parameter corresponding to the first object via a sensor disposed on the second object, wherein the sensor comprises at least two probe tips for measuring axial and radial clearances between the first and second objects;

generating a second signal indicative of a second sensed parameter corresponding to a reference geometry disposed on a continuous surface geometry of the first object via the sensor disposed on the second object;

processing the first and second signals to estimate the clearance between the first and second objects based upon a measurement difference between the first and second sensed parameters; and

controlling the clearance between the first and second objects based upon the estimated clearance between the first and second objects.

20. The method of claim 19, wherein generating the second signal comprises generating a signal corresponding to the referenced geometry having a pre-determined depth.

21. The method of claim 19, wherein generating the second signal comprises generating a plurality of signals corresponding to a plurality of reference geometries having dissimilar geometries from one another disposed on the first object.

22. The method of claim 19, wherein processing the first and second signals comprises detecting a plurality of reflected signals from respective ones of the first object and the reference geometry and performing a plurality of phase measurements to determine a phase between each of the reflected signals and corresponding excitation signals.

23. The method of claim 19, wherein generating the first and second signals comprises measuring first and second capacitance values as the first and second sensed parameters.

30. The method of claim 19, wherein generating the second signal indicative of the second sensed parameter corresponding to the reference geometry comprises generating the second signal that changes in response to the clearance between the first and second objects.

24. (canceled)

25. A system for measuring a clearance between a first object and a second object, comprising:

means for generating capacitive measurements between the first and second objects;

means for converting direct current based capacitive measurements to time varying capacitive measurements between first and second objects;

means for processing the time varying capacitive measurements to estimate a clearance between the first and second objects.

26. A rotating machinery, comprising:

a rotating component spaced apart from a stationary component, wherein the rotating component comprises a continuously circular structure having at least one reference geometry interrupting the continuity of the continuously circular structure about an axis of rotation of the rotating component; and

a clearance measurement system coupled to the rotating component and to the stationary component, wherein the clearance measurement system is configured to convert direct current based capacitive measurements between the rotating and stationary components to time-varying capacitive measurements based on the at least one reference geometry, and to estimate a clearance between the rotating and stationary components based on the time-varying capacitive measurements.