METHOD AND DEVICE FOR BURIED PIPELINE COATING DAMAGE DETECTION

摘要

PROBLEM TO BE SOLVED: To improve damage detecting sensitivity to coating and prevent malfunction caused by noise. ;SOLUTION: In order to detect the damage of coating 16 for protecting a pipe body 15 of a conduit 11, an alternating current from a signal generator 12 is fed to the conduit 11 through a coil 17. In case of the coating 16 being damaged by a soil excavating heavy machine, a signal current leaking into soil from a damaged place increases, and surface potential of the conduit 11 decreases at t2 that is damage generated time as shown in (b). Since the coil 17 is inserted, even when the output impedance of the signal generator 12 is low, the change of pipe potential is easily detected by the rise of equivalent output impedance caused by the inductance of the coil 17, and damage detecting sensitivity can be improved.;COPYRIGHT: (C)1998,JPO