| 摘要 |
<p>PURPOSE:To detect a singular point in a short period by displaying the waveform of a reflected wave returning from a high-frequency voltage application point and the waveform of a reflected wave which returns from the singular point in the underground buried metallic pipe through the high-frequency voltage application point. CONSTITUTION:A high frequency voltage is applied between the external surface of the underground buried metallic pipe 22 and one end part of a return conductor 24. Then if there are singular points 22b, 22b' in the underground buried metallic pipe 22, the reflected wave returning from the high-frequency voltage application point 22a in the underground buried metallic pipe 22 and reflected waves returning from the singular points 22a and 22b' in the underground buried metallic pipe 22 through the high-frequency voltage application point 22a are received and the waveforms of those reflected waves are displayed to calculate the distances from the high frequency voltage application point 22 on the external surface of the underground buried metallic pipe 22 to the singular points 22b and 22b'. Consequently, the positions of the singular points 22b and 22b' can be detected in a short period.</p> |
