| 摘要 |
PURPOSE:To miniaturize an apparatus and improve the reliability thereof by monitoring the internal state of a gas container through detecting a changed of bellows by an optical means provided on the outside of said gas container without using a mechanical operate contact such as microswitch. CONSTITUTION:Bellows 2a reacts to a pressure within a compressed gas insulation switchgear 1 being a detected body to expand and contract, and is monitored by a light signal through a window 2b. A light signal from LED light-emitting circuit 5 is reflected on the irregular surface of said bellows 2a, again enters an optical fiber 4, is received by a PD light-receiving circuit 6 via optical branch coupler 7, and monitored by a microcomputer 9 via input signal processing circuit 8. When bellows 2a moves, the quantity of reflected light changes so that the movement can be found. The scale of a failure is decided by the rising speed, peak value, etc. |
