| 摘要 |
The valve stem of the controlled shut-off valve has a lid and a piston movable in a cylinder. A first cylindrical chamber and a second annular chamber facing the lid are separated by a piston and connected to a low-pressure chamber by ducts extending in the housing of the shut-off valve and connecting lines connected to the ducts outside the housing. The first chamber is also connected to the inlet side of the shut-off valve via a duct extending in the housing and containing at least one control valve actuated by a control line. Closing valves are provided in the connecting lines. A throttle means having a fixed flow cross-section is disposed in the duct of the first chamber inside the housing. The duct of the second chamber has a fixed minimum cross-section.
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