| 摘要 |
PURPOSE:To monitor the leakage of a pipe or a container readily irrespective of the kinds of the pressure fluid, by detecting high frequency vibrations caused by cracks, converting the vibrations into a DC signal, and issuing warning when the rate of change in the increasing direction has exceeded a preset value. CONSTITUTION:A vibration detector 3 is fixed to a heat exchange tube 2, which pierces through a boiler 1. A high pass filter 6 is connected to the detector 3 through amplifiers 4 and 5. A detecting circuit 7, which outputs the DC signal, is connected to the output end of the filter 6. To the output side of the circuit 7, a differential circuit, which outputs a level signal corresponding to the rate of change only when the DC input signal is changed into the increasing direction, and a recorder 9, which stores the signal level, are connected. The output side of the circuit 8 is connected to a comparator 11, which compares the output of the circuit 8 and the level of a preset comparing signal and outputs a signal when the output signal level of the circuit 8 exceeds the comparing signal level. |
