Device for detecting defect of turbine rotor blade and method for detecting defect of turbine rotor blade

摘要

In a defect detection device for a turbine rotor blade, a recess is provided in a side surface of a web provided to the inner circumferential side of a stationary blade diaphragm where stationary blades are annularly arranged adjacent to turbine rotor blades. An eddy current probe is movably installed in the recess, and 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 is moved toward or away from the turbine rotor blade implanting portion, and a data analyzer determines the condition of a defect occurred in the turbine rotor blade implanting portion based on the signals detected by the eddy current probe.

主权项

1. A defect detection device for a turbine rotor blade having a turbine rotor blade implanting portion constructed by fitting a set of rotor grooves formed on a rotor disc portion of a turbine rotor and a set of blade grooves formed on a root portion of the turbine rotor blade, wherein the turbine rotor is rotatably installed inside a turbine casing, and around an outer circumference of the turbine rotor, a plurality of turbine rotor blades are annularly arranged, and wherein a stationary blade diaphragm, where a plurality of stationary blades are annularly arranged adjacent to the turbine rotor blades, is provided with an annular web in an inner circumference side thereof, and an outer circumference side thereof is fixed with the turbine casing, comprising:
a movable eddy current probe for inspecting a state of the turbine rotor blade implanting portion, installed in a recess provided in a side surface of the annular web of the stationary blade diaphragm, facing the turbine rotor blade implanting portion; a fiber rod provided with a signal line for transmitting a signal detected by the eddy current probe, connected to the eddy current probe, and set up to be movable through a hole formed in the turbine casing and an air gap formed in the stationary blade of the stationary blade diaphragm, the fiber rod being a flexible fiber rod and inserted in the air gap formed in the stationary blade of the stationary blade diaphragm to be bent in a hole in the annular web so as to change a direction of the fiber rod to axial direction of the turbine rotor, so that the eddy current probe connected to the fiber rod is moved toward or away from the turbine rotor blade implanting portion; and a data analyzer for determining a condition of a defect that has occurred in the turbine rotor blade implanting portion based on the detection signal of the turbine rotor blade implanting portion detected by the eddy current probe transmitted through the fiber rod; whereby the turbine rotor blade implanting portion is inspected by the eddy current probe under a condition that the turbine rotor is rotatably installed inside of the turbine casing.