METHOD FOR MEASURING RADIAL CLEARANCES AND SPEED OF ROTOR ROTATION IN TURBOMACHINES Russian patent published in 2017 - IPC G01B7/14 G01P3/49 

FIELD: measuring equipment.

SUBSTANCE: with the ends of the blades of a working turbomachine, an eddy-current transducer driven by a sequence of power pulses is put into operation. The information signal of the measuring circuit with the eddy-current transducer of the step-shaped form is processed by a low-pass filter and in the time dependence of this signal, the areas of the first and subsequent blades are identified in the sensitivity zone of the eddy-current transducer by exceeding the analogue signal of the given threshold level. The extreme values of the signals for the first and subsequent blades are successively extracted with the help of amplitude detection. The radial clearance of the corresponding blade is calculated by the extreme value and the radial clearances are fixed in the array of measurement results. The time intervals for reaching the analogue signal by reverse front are determined for the first and subsequent blades of the adaptive threshold level determined by dividing the extreme value by a constant coefficient. The number of blades which have passed the sensitivity zone of the eddy-current transducer is counted, and the rotation speed of rotor in rotor revolution after the passage of the last blade of the wheel is calculated.

EFFECT: possibility of combining the measurement of radial clearances and the rotation speed of the rotor by a single eddy-current transducer and performing a cycle of clearance measurement in all the blades in one rotor revolution.

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