| 摘要 |
In a flow controller, a housing structure connectable in a process line is adapted to receive a process fluid from an upstream pump and to discharge the process fluid to a downstream device. A flow restrictor mounted in the housing structure is movable between an operative position wherein the flow restrictor coacts with the housing structure to define a restricted orifice and an inoperative position. A piston movable within a hydraulic cylinder is connected, via a shaft, to the flow restrictor. A valve controlled by a timer admits a hydraulic fluid, preferably water, into the hydraulic cylinder to move the piston, so as to move the flow restrictor to the operative position and hold it, and permits the hydraulic fluid to drain after a timed interval sufficient to permit the process fluid to fill the process line between the flow controller and the downstream device.
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