| 摘要 |
PURPOSE:To obtain a detector having a wide leakage detection monitoring region and a good S/N ratio, by suppressing the noise from various machinaries in a plant by a sound shield and removing the noise generated in piping as the difference between a plurality of detection points. CONSTITUTION:For example, in the detection of the water leakage of the water supply pipe of a nuclear reactor having a large number of transport pipings, a piping group 2 is held by a support 11 and surrounded by a sound shield box 3 arranged for the purpose of sound shielding and heat insulation. The audible sound in the sound shield box 3 is detected by microphones 41-44 and outputted from an envelope circuit 5 as the envelope signals of the detection signals of the microphones 41-44. Hereupon, the difference signals not only between the microphones 41, 43 not adjacent to each other but also between the microphones 42, 44 not adjacent to each other by differential amplifiers 61, 62 and a comparator 7 judges whether the output signals of the differential amplifiers 61, 62 exceeds a positive or negative set value and, if said output signals exceeds said set value, an alarm is generated by an alarm 7 to inform the generation of leakage. |
