摘要 |
<p>Actuator control system (1) includes two parallel connected orifices (17, 18) between a pair of fluid passages (7, 8) providing communication between an actuator (15) and a flow control valve (2). Relief valves (19, 20) in series with the respective orifices (17, 18) block fluid flow through the orifices (17, 18) at low differential pressures between the fluid passages (7, 8), thereby preserving the original high pressure gain of the control valve (2) in a region about valve null. At higher differential pressures outside the valve null region, the relief valves (19, 20) open to permit restricted flow through the respective orifices (17, 18) to reduce the pressure gain of the control valve (2) in a region outside the valve null region, which effectively reduces the stiffness of the control valve (2).</p> |