| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for detecting a coating film damage position of embedded piping capable of stably measuring and surely detecting a coating film damage position. SOLUTION: The method for detecting the coating film damage position of the embedded piping comprises the steps of applying a voltage from an AC power source 2 between a coated steel pipe 1 and a ground electrode 4 via a power amplifier 3, and supplying a current. The method further comprises the step of running an inspecting pig 6 in the pipe 1 in this state. A pair of wheel electrodes 9 are provided at the pig 6 via a copying mechanism 8 in a lengthwise direction of the pig 6. A unit for measuring a voltage between the pair of electrodes 9 and recording it is provided in a body of the pig 6. A voltage between the electrodes 9 is almost none at a place except the coating film damage 5. However, when the damage 5 is moved between the two electrodes 9, a voltage is generated therebetween, and hence the presence of the damage 5 and its magnitude can be detected.
|
