| 摘要 |
<p>PURPOSE:To accurately calculate the distance from an underground hole to a joint part by excavating the ground to form the underground hole ranging from the surface of the ground to an underground pipe and catching the ultrasonic wave reflected from the joint part of the underground pipe by the receiver set to the underground pipe using the underground hole. CONSTITUTION:The oscillator 3a and receiver 3b of an ultrasonic type range finder 3 are set to the peripheral surface of an underground pipe 1 using an underground hole 2. If necessary, the outer peripheral surface of the underground pipe 1 is cleaned by a proper grinder in order to set the oscillator 3a and the receiver 3b. Ultrasonic wave are emitted to the underground pipe 1 by the oscillator 3a so as to go toward the joint parts 1a, 1b on both sides of the pipe 1 and the ultrasonic waves reflected from the joint parts 1a, 1b of the underground pipe 1 among the ultrasonic waves propagating through the underground pipe 1 are caught by the receiver 3b. As a result, the positions of the joint parts can be certainly and accurately detected.</p> |
