| 摘要 |
PROBLEM TO BE SOLVED: To improve the reliability of an open/close device having a vacuum valve, by certainly detecting vacuum leakage of the vacuum valve with a simple structure.SOLUTION: A vacuum leakage monitoring device of a vacuum valve includes: a detection sensor 5 for detecting a signal component in a metal container 1 having a vacuum valve 3; means 12 for amplifying the signal component; envelope detecting means 13 for detecting an envelope of the amplified signal component; a first band pass filter 15a for extracting the signal component of frequency double of commercial frequency of the signal component of which the envelope is detected; a second band pass filter 15b for extracting the signal component of a frequency band of 10 kHz to 100 kHz of the amplified signal component; determining means 18 which determines that vacuum leakage from a vacuum vale 1 occurs when the signal component of the frequency double of the commercial frequency and the signal component of the frequency band of 10 kHz to 100 kHz simultaneously exceed a threshold; and a display portion 19 for displaying the determination. |
