30 November 2022

Steam Turbine Seal Bore | Turbine Fundamentals and Basics | Basic Aspects of Steam Turbine Maintenance | Part#3 | Content-10 |

SEAL BORE

  • Seal Bore readings are the Rotor Centering readings with respect to the Bearing Pedestals.
  • It is measured by means of inside micrometers from the oil guard Seat surface to the surface of the rotor Journal. At each location it is measured at the three points, Left, Right, bottom
  • Seal bore readings are the reference readings for any correction and normally should not change.
  • But over a period of time due to change in foundation characteristics it can lead to change in seal bore readings.

Check List:

1.) Ensure inside micrometers used for taking seal bore readings are calibrated.
2.) If the seal bores reading are very awkward during Dismantling, same can be improved upon during the finalization of Alignment and slope. But in the end Alignment is theĀ  Top priority.
3.) If there is no margin of improvement of seal bore then contractor should be asked to demonstrate the removal of bearing from the rotor.
4.) If the bearings come out then it is OK . But if there is problem then one has to go for pedestal rectification by offset machining for ease of bearing removal.

 

HIP seal bore clearances checking using inside micrometer

Remove HIP after checking seal bore clearances & Put in stand at turbine floor

Seal bore readingsĀ  –Just for Reference only

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