DEVICE FOR DETECTING DEFECT OF TURBINE ROTOR BLADE AND METHOD FOR DETECTING DEFECT OF TURBINE ROTOR BLADE

摘要

A device for detecting the defect of a turbine rotor blade, wherein a portion for implanting a turbine rotor blade is constituted by fitting a blade groove formed at the root of turbine rotor blades arranged on the outer circumference of a turbine rotor installed rotatably in the turbine casing to a rotor groove formed in a rotor disc portion, a recess is provided in the side face of a web provided on the inner circumferential side of a stationary blade diaphragm where stationary blades are arranged annularly and contiguously to the turbine rotor blades, an eddy current probe for detecting a state at the portion for implanting a turbine rotor blade is installed movably in that recess, a rod provided with a signal line connected with the eddy current probe and transmitting a signal detected by the eddy current probe is arranged so as to move with in a hole in a turbine casing and an air gap formed in the stationary blade diaphragm, the eddy current probe connected with the rod is made to move toward or away from the portion for implanting a turbine rotor blade, and a data analyzer for judging a defect condition occurring at the portion for implanting a turbine rotor blade based on the detection signal from the eddy current probe is provided.