Turbine blade clearance on-line measurement system
AssigneeSiemens Westinghouse Power Corporation
InventorMichael Twerdochlib
Life of this patent
Estimating the term…
Abstract
A monitoring system for measuring the gap between a turbine blade and a stationery component of a turbine, includes an insertion probe having a sensor which is moved radially within the gap to a pre-selected distance from the turbine blade as measured by the sensor's output. The distance the sensor moved from a reference point to arrive at the pre-selected distance from the blade is also monitored and the gap between the fixed turbine component and the blade is determined from these measurements.
Claims21
A system for monitoring the clearance between a plurality of turbine blades and a stationary portion of the turbine, comprising:
- sensor means having an exterior tubular support structure with an axial dimension, that supports a centrally disposed drive shaft that is reciprocally mounted within the support structure to move along the axis thereof, said sensor means positioned within said stationary portion of the turbine and aligned so that the reciprocal movement of the drive shaft moves a forward end of the drive shaft, closest to the turbine blades, towards and away from the turbine blades;
- a proximity sensor that is responsive to being positioned substantially a preselected distance from the turbine blade to provide a given output representative of the preselected distance, supported at the forward end of and coupled to said drive shaft so that said proximity sensor moves with the drive shaft;
- a motor coupled to said drive shaft and operable to move said drive shaft a given distance either towards or away from the turbine blades and responsive to such movement to provide a position output from which the sensor position can be determined relative to its distance from a predetermined calibration point;
- and
- means for monitoring the sensor output and controlling the motor movement, so the sensor is substantially positioned the preselected distance from the blade determined by monitoring for the given output, and for monitoring the position output to determine the distance of the blade from the calibration point.
A method of monitoring the clearance between a plurality of turbine blades and a stationary portion of the turbine comprising the steps of:
- positioning a proximity sensor at a calibration point relative to the stationary portion of the turbine;
- driving the proximity sensor away from the stationary portion of the turbine towards the blades while monitoring an output signal of the proximity sensor;
- identifying from the output of the proximity sensor when the proximity sensor is at a preselected distance from the blades;
- monitoring a distance of movement of the proximity sensor from the calibration point to a travel point along the path of movement of the proximity sensor where the proximity sensor is at the preselected distance from the blades;
- and
- determining from the distance of movement the spacing between the stationary portion of the turbine and the blades.
Dependencies are inferred from the claim text.