METHOD AND SYSTEM FOR RUB DETECTION IN A STEAM TURBINE

• US 20080240902A1
• Filed: 03/28/2007
• Published: 10/02/2008
• Est. Priority Date: 03/28/2007
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Cooper, Gregory Edward
• Application Number:
  US11/692,551
• Publication Number:
  US 20080240902A1
• Time in Patent Office: Days
• US Class Current: 415/48
• CPC Class Codes: F01D 21/12 responsive to temperature
• CPC Class Codes: F05D 2220/31 in steam turbines
• CPC Class Codes: F05D 2270/112 by limiting temperatures
• CPC Class Codes: F05D 2270/3032 excessive temperatures, e.g. caused by overheating
• CPC Class Codes: G01K 1/026 arrangements for monitoring a plurality of temperatures, e.g. by multiplexing
• CPC Class Codes: G01K 13/04 for measuring temperature of moving solid bodies
• CPC Class Codes: G01N 19/02 Measuring coefficient of friction between materials testing of tyres G01M17/02; determinations of friction coefficient used in vehicle braking or traction control systems B60T8/172

Abstract

A method for detecting rubbing between components in a steam turbine, the method includes: sensing a temperature at a plurality of locations on a casing of the steam turbine; comparing the sensed temperatures of the plurality of locations; detecting the rubbing between the components if one of the plurality of locations has a higher sensed temperature than the sensed temperature at the other plurality of locations, and reporting the rub as being at a location near the one of the plurality of locations having the higher sensed temperature.

Claims

1. A method for detecting rubbing between components in a steam turbine, the method comprising:

sensing a temperature at a plurality of locations on a casing of the steam turbine;

comparing the sensed temperatures of the plurality of locations;

detecting the rubbing between the components if one of the plurality of locations has a higher sensed temperature than the sensed temperature at the other plurality of locations, and

reporting the rub as being at a location near the one of the plurality of locations having the higher sensed temperature.

2. A method as in claim 1 wherein the plurality of locations are in an annular array perpendicular to a rotor axis.

3. A method as in claim 1 wherein the plurality of locations are four locations arranged symmetrically around the casing in a plane perpendicular to a rotor in the turbine.

4. A method as in claim 3 wherein the four locations arranged along vertical and horizontal lines extending through the plane.

5. A method as in claim 1 wherein the detection of the rubbing includes comparing each of the sensed temperatures to at least one of an average of sensed temperatures, a mean of sensed temperatures and to each of the other sensed temperatures in the array.

6. A method as in claim 1 wherein the plurality of locations are arranged in an annular array in the casing and around a row of steam turbine buckets on a rotor of the turbine.

7. A method as in claim 1 wherein the plurality of locations are near an inlet to the turbine.

8. A method as in claim 1 wherein the plurality of locations are in a middle of the turbine and substantially mid-way between rotor bearings supporting a rotor to the turbine.

9. A method to detect rubbing in a steam turbine comprising:

monitoring temperature sensors in at least one sensor array in a casing for the turbine;

comparing temperature measurements of all sensors in array;

identifying a hottest temperature in array from the comparison;

determine if the hottest temperature is beyond a threshold level;

identifying a sensor reporting the hottest temperature beyond the threshold, and

issuing a warning of rubbing potentially occurring at a position near the identified temperature sensor.

10. The method of claim 9 further comprising periodically repeating the steps of the method.

11. A method as in claim 9 wherein the sensor array includes a plurality of sensors arranged in a plane perpendicular to an axis of a rotor in the turbine.

12. A method as in claim 9 wherein the array of plurality of locations are four locations arranged symmetrically around the casing in a plane perpendicular to a rotor in the turbine.

13. A method as in claim 12 wherein the array includes four sensors arranged along vertical and horizontal lines extending through the plane.

14. A method as in claim 9 wherein the comparison includes comparing the measurements of each of the sensors to at least one of an average of sensed temperatures, a mean of sensed temperatures and each of the other temperature measurements in the array.

15. A method as in claim 9 wherein the sensors include sensors arranged in an annular array in the casing and around a row of steam turbine blades on a rotor of the turbine.

16. A system to detect rubbing in a steam turbine having a casing around a rotor, the system comprising:

at least one array of temperature sensors mounted in the casing proximate to an inside casing surface facing the rotor, and

a controller monitoring temperature signals from each of the temperature sensors in the array, wherein said controller issues a rubbing warning if one of the temperature signals reports a temperature substantially hotter than other temperatures reported by the array.

17. A system as in claim 16 wherein the at least one array is arranged in a plane perpendicular to a rotational axis of the rotor.

18. A system as in claim 17 wherein the at least one array includes four sensors arranged along vertical and horizontal lines extending through the plane.

19. A system as in claim 16 wherein the controller compares each of the sensed temperatures to at least one of an average of sensed temperatures, a mean of sensed temperatures and to each of the other sensed temperatures in the array.

20. A system as in claim 16 wherein the at least one array is positioned at least at one of proximate to a row of turbine buckets at an inlet to the turbine and a row of turbine buckets between a pair of bearings supporting a rotor of the turbine.