PAINT FILM DAMAGE DETECTION METHOD OF BURIED COATED STEEL PIPE

摘要

PROBLEM TO BE SOLVED: To provide a paint film damage detection method of a buried coated steel pipe, capable of detecting a minute damage by suppressing the influence of other damages in a case of having plural damages. ;SOLUTION: A low-frequency alternating voltage is applied between a buried coated steel pipe 3 and an earthing pole 9, and the potential difference between two points is detected by two electrodes 1, 2 arranged along the rectangular direction against the pipe axis direction of the buried coated steel pipe 3. A potential difference distribution of the ground surface in the rectangular direction against the pipe axis direction of the buried coated steel pipe 3 is obtained by changing the positions, and a damage position of the buried coated steel pipe 3 is detected based on the potential difference distribution of the ground surface.;COPYRIGHT: (C)2000,JPO