| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique enabling shut-off valve opening and closing determination from far away by a simple configuration. SOLUTION: In a state (a valve element 4a opened state) of a latch lever 6 latched to a movable core 3d, a light signal from a light transmitting/receiving part 5a of an optical sensor 5 hits the latch lever 6 and it is reflected and returned to the light transmitting/receiving part 5a. By detection of the light signal, it can be determined that the valve element 4a is in an opened state. On the other hand, in a released state (a valve element 4a closed state) of a latch of the latch lever 6, the signal sent from the light sending and receiving part 5a passes above the latch lever 6, and it hits a cork thin plate 2c of a lid part 2b. In this case, since the light signal is irregularly reflected, a detection signal in the light sending and receiving part 5a is a threshold or less. Thereby, it can be determined that the valve element 4a is in a closed state. In such a manner, opening and closing of the shut-off valve 4 can be determined by the optical sensor 5. COPYRIGHT: (C)2010,JPO&INPIT
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