| 摘要 |
A control arrangement (10) for a shut-off valve actuable by vacuum and intended for use in vacuum waste water systems, comprising a first valve (14) which is actuated by static pressure of collected waste water, and including a chamber (56) which can be put under vacuum via the first valve, whereby a second valve (20), charged by a spring (71), is abruptly opened when the pressure in the chamber drops below a preset level, so that vacuum reaches the shut-off valve and opens it, and, in case static pressure is reduced, the first valve closes and the chamber is gradually ventilated until the pressure in this chamber reaches a preset level at which the second valve and in turn the shut-off valve abruptly close.
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