| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum device in which an assembling workability of the vacuum valve device is outstandingly enhanced and a reliability of the vacuum valve device is also outstandingly enhanced. SOLUTION: In the vacuum valve device 30, a piston 34, a bellows diaphragm 36 and a return spring 38 are disposed in a cylinder 32 and a valve body 42 is mounted to a tip end of a piston rod 40 connected to the piston 34 by a nut 43. A detector 60 for detecting a return motion of the piston 34 is provided with a casing 62; an operation body 64 which is arranged in the casing 62 and of which a projection is projected from the casing 62; and a return spring 66 for urging the operation body to a projection direction of the projection 64a; a magnet 68 buried in the operation body 64; and a lead switch 70 sensitive to a magnetic flux of this magnet 68.
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