| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of a detecting defective part in a coating capable of detecting the presence of the coating defective part of an embedded metal pipe, and a position of the coating defective part, without traffic regulation, or with only a short time of the traffic regulation. SOLUTION: In this method of detecting the defective part in the coating of the embedded metal pipe 1, a signal voltage is impressed between the embedded metal pipe 1 and the ground by a signal generator 2, pipe-to-ground potentials of the embedded metal pipe 1 to the ground are measured in a plurality of measuring points 3 separated from a signal voltage impressed point, and the coating defective part is detected based on changes in attenuation amounts of the pipe-to-ground potentials obtained from the measuring points 3. COPYRIGHT: (C)2005,JPO&NCIPI
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