| 摘要 |
Apparatus for locating an object in a pipeline, comprising a transmitting station having means for transmitting in the pipeline acoustic emissions having a frequency in the range from 20 KHz to 200 KHz; a receiving station having a receiver capable of receiving the acoustic emissions transmitted by the transmitting station; one of the receiving station and the transmitting station being located at a known position on the pipeline and the other of the receiving station and the transmitting station being located on the object; and clock means to determine the time taken for the acoustic emissions to travel between the transmitting station and the receiving station. |
