PAINT FILM DAMAGE DETECTION METHOD OF BURIED PAINT 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 even a minute damage on the under surface of a pipe body of the buried coated steel pipe, and capable of specifying the position in the circumferential direction. ;SOLUTION: A low-frequency alternating voltage is applied between a buried paint-coated steel pipe 3 and an underground earthing pole 9, and the potential difference between two points is detected by two electrodes 1, 2 arranged in the depth direction in a vertical pit 10 formed near the buried paint-coated steel pipe 3. An underground potential difference distribution along the vertical pit 10 is obtained by changing the depth of the two electrodes 1, 2 in the vertical pit 10, and a damage 4 position of the buried paint-coated steel pipe 3 is detected based on the potential difference distribution.;COPYRIGHT: (C)2000,JPO