| 摘要 |
The valve control gas spring in a dome (12) is compensated by a variable orifice at which a pressure is derived and fed back to the control diaphragm (20) of the valve via a tube (28). The orifice is defined by an annular member (26), movable against a preloaded spring (88) and a second orifice is defined between the member and the wall of a passage (24) in which it moves. The second orifice opens only after the preload is overcome by the force of fluid flowing through the member after passing through the valve seat. The valve can handle liquids or gases and is applicable to the accurate control of pressure or flow rate in the chemical and process industries. |
