| 摘要 |
<p>The valve consists of two balls which can be displaced between two extreme positions by pistons actuated by flexible membranes. In either extreme position, each ball is pressed on to a ring seal. Each ball and associated seals form three chambers, one between the seals and the others external to the seals. One chamber of each valve is connected to the pressure source and the other to the discharge duct. A solenoid operated servo valve controls pressure on one membrane and, by virtue of interconnections between the valves, admission of working fluid to drive the jack on one direction. Interruption of the supply to the membrane and discharge of the fluid through the servo valve, drives the jack the other way.</p> |
