| 摘要 |
<p>PURPOSE: To accurately and efficiently detect the direction where an underground detecting object is positioned from an aboveground optional position without requiring a great deal of labor. CONSTITUTION: A transmission coil 6 is inserted into a buried pipe 1 being a detecting object, and is moved inside. An alternating current is supplied to this transmission coil 6 from a signal supply device 8, and a magnetic field is generated, and this is detected by a magnetism detecting device 10 arranged at an aboveground observation point, and the position of the transmission coil 6 is detected. The transmission coil 6 is asynchronously rotated with the supplying alternating current around the central axis C of the buried pipe 1 by a rotary means 7, and the magnetic field generated from the transmission coil 6 is detected by plural receiving coils 14 and 15 of a magnetism detecting device 10 aligned and arranged on the same plane toward the transmission coil 6. Signals generated in the receiving coils 14 and 15 and a supply signal to the transmission coil 6 are synchronously detected, and the signal according to a turning angle of the transmission coil 6 is detected. Phases of the signal according to the turning angle of the transmission coil 6 detected by the plural receiving coils 14 and 15 are compared with each other, and the aligning direction of the receiving coils 14 and 15 whose phases coincide with each other is found, and the position of the buried pipe 1 is detected.</p> |
