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

摘要

A defect detection device for a turbine rotor blade, wherein a turbine rotor blade implanting portion is constructed by fitting a set of rotor grooves formed on a rotor disc portion with a set of blade grooves formed on each root portion of turbine rotor blades arranged around the outer circumference of a turbine rotor rotatably installed in a turbine casing; a recess is provided in the side surface of a web provided to the inner circumferential side of a stationary blade diaphragm where stationary blades are annularly arranged adjacent to the turbine rotor blades; an eddy current probe for inspecting the state of the turbine rotor blade implanting portion is movably installed in the recess; a rod provided with a signal line for transmitting a signal detected by the eddy current probe, connected to the eddy current prove, is set up to be movable through a hole in a turbine casing and an air gap formed in the stationary blade diaphragm; the eddy current probe connected to the rod is moved toward or away from the turbine rotor blade implanting portion; and a data analyzer is provided for determining the condition of a defect occurred in the turbine rotor blade implanting portion based on the signals detected by the eddy current probe.