PURPOSE: To perform monitoring with high accuracy without always using an expensive optical technique, by finally evaluating erosion quantity using an erosion quantity initial estimation device in such a state that the timewise change of erosion quantity becomes constant.
CONSTITUTION: A non-contact type blade surface shape measuring means 20 utilizing laser beam is mounted on the stationary member of the low pressure part of a steam turbine and the surface profile of a blade in an initial state is preliminarily operated at a stationary time by an initial profile measuring operator 21. An erosion quantity after an operation elapse time ΔT is operated by a blade surface erosion quantity evaluation operator 24. The estimated erosion quantity is corrected from the ratio of the timewise change quantity of the output Ec of an erosion quantity initial estimation device 27 to that of the output E of the blade surface erosion quantity evaluation operator 24. The measuring processing of the erosion quantity based on the detection values of these optical means is performed only for a time until reaching a steady region and, thereafter, final evaluation is performed using the operationally processed value of the erosion quantity initial estimation device 27. By this method, the erosion advance state of a turbine blade can be effectively monitored with high accuracy.
TAKI TOMOYUKI
TSUBOUCHI KUNIYOSHI
SATO TAKESHI
Next Patent: METHOD FOR WIDE AREA MONITOR OF FLUID LEAKAGE