| 摘要 |
PURPOSE:To enable detection of the existence and position of a joint by detecting a reflected wave appearing between a pulse-shaped acoustic wave transmitted from the other end side of a pipeline and a reflected wave from an open or closed end. CONSTITUTION:A longitudinal straight pipe part 7, for instance, of a supply pipe 1 is disconnected from a meter cock and a detecting part (an acoustic wave transmitting part 9, a receiving part 10) 11 is fitted to the upper end of the straight pipe part 7. The transmitting part 9 is constructed of a speaker converting a signal from a pulse generating means 12 into an audio signal, and an output signal of a microphone constructing the receiving part 10 is inputted to a signal processing means (CPU, etc.) 14 through a preprocessing means (an amplifier, an A/D converter, etc.) 13. A signal obtained by the processing means 14 is outputted to an output means 15. Two detection outputs of a transmitted pulse-shaped acoustic wave and a reflected wave from an open end of the pipeline 1 obtain high levels and a detection output having a low level appears between the two. This is a reflected wave from a joint. This wave can be discriminated distinctly and the presence of the joint can be detected. The position of the joint can be calculated from an acoustic wave pass time and a sound velocity. |
