| 摘要 |
Flow control valve has a valve housing (32, 34) that provides fluid inlet (42) and outlet (44) at opposite ends coaxial with a longitudinal axis (40). A control body (36) is supported coaxially within the housing, providing a flow passage (37) for symmetric flow of fluid around the control body, having preferably cross sectional area kAi relating to an effective inlet cross sectional area Ai wherein k is about 1.1 to about 1.2. A valve member (56) is carried at a downstream end of the control body and positioned by a valve actuator (54). A control port (52) extends through support structure for the control body for communication with the actuator, according to one embodiment for which an external fluid control (88) controllably provides control fluid to the actuator under pressure through the port for controllably driving the actuator along the axis (40) for precise flow control. |
