| 摘要 |
Improved closed fail-safe valve comprises (a) a body having a flowway through it; (b) a closure member moveable between open and closed flowway; (c) means in which energy is generated in response to a pressure differential across the closure member, while the closure member is in the closed position; (d) means operable, upon a reduction in the pressure differential, for releasing generated energy to move the closure member from closed to open position, and hold it open so long as the controlled condition is maintained; and (e) means operable, upon loss of the controlled condition, for releasing further generated energy to move the closure member from open to closed fail-safe position.
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