NOISE SUPPRESSION IN ROTARY SENSOR REMOTE FIELD EDDY CURRENT FLAW DETECTOR

摘要

PURPOSE: To detect flaw in an intricate piping system including curved pipes using a relatively simple apparatus. ;CONSTITUTION: In the remote field eddy current flaw detector in which the phases of an electromagnetic wave transmitted from a transmission coil and an electromagnetic wave received by a receiving coil are measured at each appropriate position of a flaw sensor 1 and an objective point is detected based on a phase distribution data with respect to the position of a pipe, measurements are repeated a plurality of times for an objective pipe 13 to obtain a phase distribution data each time and then the plurality of data are averaged. Since the flaw sensor 1 is run through within a pipe while rotating, travelability is enhanced especially at insertion easiness through an obstacle or a curve. It has relatively simple structure and applicable to a small diameter pipe. Furthermore, it requires no purging nor digging and can be manufactured at low cost.;COPYRIGHT: (C)1995,JPO