Turbomachine cold clearance adjustment

Patent metadata

Field	Value
Publication number	US-9587511-B2
Application number	US-201314105834-A
Country	US
Kind code	B2
Filing date	Dec 13, 2013
Priority date	Dec 13, 2013
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A system and method for measuring and adjusting rotor to stator clearances is disclosed, as well as a turbomachine embodying the system and method. In an embodiment, a turbomachine is assembled, including a stator having an upper and a lower stator shell, and a rotor disposed within the stator. A cold clearance between the rotor and the stator is determined at each of a plurality of clearance measurement points using an in situ clearance sensor system. Each of the clearance measurement points is axially spaced from each other clearance measurement point. The cold clearance between the rotor and the stator is adjusted based on the determined cold clearances, by displacing one of the upper stator shell or the lower stator shell relative to a foundation, thereby changing a shape of the upper stator shell or the lower stator shell to accommodate a position of the rotor within the stator.

First claim

What is claimed is:

1. A turbomachine comprising:
a rotor having a plurality of blade stages;
a stator surrounding the rotor, the stator including a lower stator shell and an upper stator shell;
an in situ clearance sensor system for determining a cold clearance between the rotor and the stator at each of a plurality of clearance measurement points, wherein each of the plurality of clearance measurement points is disposed at a position axially spaced from each other clearance measurement point,
the in situ clearance sensor system including a plurality of voltage drop sensors, wherein a voltage drop sensor is disposed at each clearance measurement point in the plurality of clearance measurement points, and the voltage drop sensor at each clearance measurement point is embedded into one of the lower stator shell or the upper stator shell such that a radially outer edge of the voltage drop sensor is substantially flush with an inner surface of the upper or lower stator shell in which the voltage drop sensor is embedded,
wherein the voltage drop sensor at each clearance measurement point is axially aligned with a rotor blade tip of an upstream stage of blades, and the voltage drop sensor is configured to measure a voltage drop across a clearance between a tip of the voltage drop sensor and the rotor blade tip; and
a plurality of displacement adjustment devices axially spaced from each other, for displacing a position of one of the upper stator shell or the lower stator shell relative to a foundation and based on the clearance determined by the in situ clearance sensor system, thereby adjusting the cold clearance between the rotor and the stator.

2. The turbomachine of claim 1 , wherein the in situ clearance sensor system further comprises a laser measurement device removably affixed to one of:
a rotor blade in a final stage of blades, the laser measurement device being configured to measure a tops-on clearance between the tip of the rotor blade and the inner surface of the upper or lower stator shell while the upper stator shell, the rotor, and the lower stator shell are assembled together, or
a nozzle ring or a nozzle cover, the laser measurement device being configured to measure a tops-on clearance between a radially inward tip of a nozzle and the rotor.

3. The turbomachine of claim 1 , wherein the plurality of clearance measurement points further comprises between two and five axially spaced clearance measurement points.

4. The turbomachine of claim 1 , wherein the plurality of displacement adjustment devices are disposed at a horizontal joint between the upper stator shell and the lower stator shell.

5. The turbomachine of claim 1 , wherein at least one of the plurality of clearance measurement points is disposed on an underside of the lower stator shell.

6. The turbomachine of claim 1 , wherein each of the displacement adjustment devices further comprises one of: a jacking screw, a set screw, or a fixator, and wherein each of the displacement adjustment devices further comprises a lock that is one of: an epoxy or a cement.

7. The turbomachine of claim 1 , wherein each of the displacement adjustment devices further comprises one of a hydraulic cylinder or a pneumatic cylinder, and
wherein each of the displacement adjustment devices further includes a valve for locking a position of the displacement adjustment device.

8. A method for adjusting rotor to stator clearances comprising:
assembling a turbomachine including a stator, the stator having a lower stator shell and an upper stator shell, and a rotor disposed within the stator;
determining a cold clearance between the rotor and the stator at each of a plurality of clearance measurement points using an in situ clearance sensor system, wherein each of the clearance measurement points is axially spaced from each other clearance measurement point,
wherein determining the cold clearance further comprises using an in situ clearance sensor system that includes a plurality of voltage drop sensors, wherein a voltage drop sensor in the plurality of voltage drop sensors is embedded into one of the lower stator shell or the upper stator shell at each of the plurality of clearance measurement points, each voltage drop sensor being configured to measure a voltage drop across a clearance between a tip of the sensor and a rotor blade tip,
wherein the voltage drop sensor is axially aligned with an upstream stage of blades; and
adjusting the cold clearance between the rotor and the stator based on the determined cold clearances, the adjusting including: changing a shape of the upper stator shell or the lower stator shell by displacing one of the upper stator shell or the lower stator shell relative to a foundation to accommodate a position of the rotor within the stator.

9. The method of claim 8 , further comprising:
after adjusting the cold clearance between the rotor and the stator, re-determining the cold clearance between the rotor and the stator at each of the plurality of clearance measurement points; and
if the re-determining indicates that the cold clearance does not meet a pre-determined threshold, re-adjusting the cold clearance between the rotor and the stator, the re-adjusting including using a displacement adjustment device to displace one of the upper stator shell or the lower stator shell relative to the foundation based on the re-determined cold clearances, thereby changing the shape of the upper stator shell or the lower stator shell to accommodate the position of the rotor within the stator.

10. The method of claim 8 , further comprising rotating the rotor within the stator at a speed of about 0.25 to about 8 revolutions per minute (RPM) while determining the cold clearances between the rotor and the stator at each of the plurality of clearance measurement points.

11. The method of claim 8 , wherein determining the cold clearance further comprises using an in situ clearance sensor system that includes a laser measurement device removably affixed to one of:
a rotor blade in a final stage of blades, for measuring a tops-on clearance between the rotor blade tip and an inner surface of the stator while the upper stator shell, the rotor, and the lower stator shell are assembled together, or
a nozzle ring or a nozzle cover, for measuring a tops-on clearance between a radially inward tip of a nozzle and the rotor.

12. The method of claim 11 , further comprising: removing the laser measurement device from the rotor blade after a final adjustment is made.

13. The method of claim 8 , wherein the adjusting further comprises adjusting a vertical position of the displacement adjustment device, wherein the displacement adjustment device includes one of: a jacking screw, a set screw, a fixator, a hydraulic cylinder, or a pneumatic cylinder.

14. The method of claim 13 , further comprising: after adjusting the cold clearance between the rotor and the stator, locking a position of the displacement adjustment device.

15. A system for adjusting a rotor-to-stator clearance in a turbomachine, the system comprising:
an in situ clearance sensor system for determining a cold clearance between a rotor and a stator at each of a plurality of clearance measurement points, the stator including a lower stator shell and an upper stator shell, and the rotor being disposed within the stator,
wherein the in situ clearance sensor system includes at least one voltage drop sensor inserted into one of the lower stator shell or the upper stator shell at a clearance measurement point, for measuring a voltage drop across a clearance between a tip of the voltage drop sensor and a rotor blade ti

Assignees

• Gen Electric

Inventors

• Willett Jr Fred Thomas
• Koza Kenneth Michael

Classifications

• Y10T29/49323

  Assembling fluid flow directing devices, e.g., stators, diaphragms, nozzles · CPC title

• F05D2270/821

  Displacement measuring means, e.g. inductive · CPC title

• G01B7/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B7/30 takes precedence) · CPC title

• F05D2230/644

  for adjusting the position or the alignment, e.g. wedges or eccenters · CPC title

• G01B11/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00) · CPC title