To automatically adjust energizing force of a spring which closes a vacuum valve according to the degree of vacuum of a vacuum water feed pipe.
A control device for a vacuum valve comprises: a changeover part 52 which changes over to/from an open position at which a valve body 35 is moved to a valve opening position and from/to a close position at which the valve body 35 is moved to a valve closing position; a changeover cylinder 98 which is partitioned into a first pressure receiving chamber 103 connected to a vacuum water feed pipe 6 side and a second pressure receiving chamber 104 having a lower degree of vacuum than that of the first pressure receiving chamber 103, and in which the side of the first pressure receiving chamber 103 opposite to the second pressure receiving chamber 104 is partitioned into a constant pressure chamber (fluid storage chamber 106); a first piston 122 which is movable from a non-operation position to an operation position; a second piston 126 which is movable from a vicinity position which it approaches to the first piston 122 to a separation position; an energizing spring 128 which is disposed between the first and second pistons 122, 126 and energizes the first piston 122 toward the operation position; and a closing operation part 125 provided on the first piston 122 and changes over the changeover part 52 from the open position to the close position.
TAKAGAKI NAOTAKE
| JP2010281141A | 2010-12-16 | |||
| JPH09196231A | 1997-07-29 | |||
| JP2012077473A | 2012-04-19 |
| WO2010113767A1 | 2010-10-07 |
Mitsuo Tanaka
Yoshiyuki Maebori
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