Administering corrosion protective covering 1 on the corrosion protective covering damage position method of detection null outside of the embedding metallic conduits

摘要

PROBLEM TO BE SOLVED: To provide a method for detecting a damaged location in a corrosion- proof coating of embedded metal pipes capable of heightening work efficiency, reducing cost, and accurately knowing the damaged location in the coating.;SOLUTION: A signal current is passed between a damaged part 3 in the coating of the metal pipe 2 embedded in the ground to which the corrosion-proof coating 1 is applied and a counter electrode 5 embedded in the ground 4 from a measuring signal transmitter 6. The potential difference of a ground surface is detected by each of wheel electrodes 10 in a receiving device 9 to detect damage in this method for detecting the damaged location in the corrosion-proof coating in the embedded metal pipe. Two types of different carrier-frequency signal currents are simultaneously supplied across the embedded metal pipe 2 and the embedded counter electrodes 5 and 7, and the signals of the two types of frequency components detected by the receiving device 9 are compared with each other to determine the damaged part 3 in the coating.;COPYRIGHT: (C)2003,JPO