| 摘要 |
Pilot-controlled pneumatic valve comprising a body 10, 30 comprising an upstream space 1 able to be connected to an upstream pressure source and a downstream space 2 able to be connected to a downstream use, a valve element 53 capable of shutting off and opening a passage between the upstream space 1 and the downstream space 2, the valve element 53 being applied against its seat 19A by a spring 56 and being able to move by action of a rod 35 securely fixed to a membrane 31 arranged in a chamber 31A, 31B within the said body 10, 30 and separating the said chamber 31A, 31B into a first and a second compartment 31A, 31B, the said first compartment 31A comprising an outlet and the said second compartment 31B being able to be connected to pilot-control means 45 in order to establish therein a first pressure which is sufficient for moving the membrane 31 in a first direction in order to open the valve element 53 and a second pressure in order to move the membrane 31 in the other direction in order to close the valve element 53, characterised in that the rod 35 is hollow and traverses the membrane 31 and the second compartment 31B and in that it is in communication with the outside. Possibility for draining the downstream space 2 of the valve after its closure. <IMAGE>
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