| 摘要 |
A piston-like member slides within a valve body, with one end sealingly engageable against a valve seat communicating with an inlet port. The other end of the piston-like member forms a movable wall of an expansible chamber which, when it expands, moves the member toward valve closure. Preferably, both ends of the piston-like member are engaged against diaphragms, one of which seals against the valve seat to close the valve and the other of which serves as the movable wall of the expansible chamber. The valve may be solenoid operated, preferably with a solenoid of linear force characteristics, the solenoid being connected to the piston-member via a pivoted arm. The solenoid-controlled valve can be used to control the flow of a very highly pressurized or large-volume inlet fluid with a relatively low solenoid force by connecting the expansible chamber with inlet pressure, so that inlet pressure acts on both ends of the piston-like member, tending to balance forces. Without solenoid operation, the valve can serve as a relief valve or as a pilot operated valve with pilot pressure connected to the expansible chamber. The valve can also serve as a pressure regulator for establishing a constant ratio of outlet pressure to inlet pressure, by connecting the valve outlet with the expansible chamber, with the expansible chamber diaphragm being of larger effective area than the valve closure diaphragm.
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