PURPOSE: To simply measure a leak width of liquid, by a method wherein a leak width of liquid is determined by a difference between a time, for which a pulse propagates over the whole length of a cable, detecting leakage of liquid from a change in impedance, in the case of liquid permeation, and a time for which it propagates in a similar manner in the case of no liquid permeation.
CONSTITUTION: According to an instruction of a controller 2, a pulse from a pulse generator 1 is applied a detecting cable 3 running along an oil pipe line and the like, the pulse reflects from opposite ends of an oil leak part 4, and reflects also from the terminal of the cable 3 whereto a terminal impedance 5, being difference from the characteristic impedance of the cable 3, is connected. A sample hold time at a sample hold circuit 7 is controlled by the controller 2, and a waveform of a terminal reflection wave is detected through an A/D converter 8 to determine a time for which the pulse propagates the cable 3. A difference between a propagating time in the case of liquid leak and that in the case of no liquid leak is found, and this enables to perform a simple measurement of a leakage width corresponding to a change in the propagating speed of the pulse based on a change in impedance due to leakage.
MASUDA KIYOSHI
HIRAI SABUROU
| JPS5323687A | 1978-03-04 |