METHOD FOR SPECIFYING COATING DAMAGE PART OF BURYING LINE

摘要

PROBLEM TO BE SOLVED: To distinguish a noise ascribable to an induced electric current generated from buildings surrounding a burying pipe from fluctuations in a magnetic field ascribable to an electric current leaked from the burying pipe. SOLUTION: While transmitting a reference AC signal to the buried pipe 10, a search coil 30 on the ground is moved so as to detect a phase of a signal induced in the search coil 30 and measure an amount of change in the phase. COPYRIGHT: (C)2004,JPO