| 摘要 |
PURPOSE:To automatically compensate for an error of inspection output depending on distance between a flow detecting coil and a steel pipe being inspected, by providing a range finder. CONSTITUTION:A steel pipe 2 to be inspected is carried over onto a defect-detecting line. By advancing of a transfer car 24 on a track 25 and inspecting the steel pipe 2, flaw-detecting heads 8, 9 and 10 are mounted and set onto an outside surface, an inside surface and an end surface, respectively. The transfer car 24 advances by a preset flaw-detecting range to search for flaw. A range-finding coil 32 is provided in the same head 9 together with a flaw-detecting coil 28, and by an eddy current signal a range finder measures a distance between the flaw-detecting coil 28 and the steel pipe 2. variation of impedance of the flaw-detecting coil 28 is detected through an amplifier 30 and a synchronous wave detector 36. |
