| 摘要 |
<p>A pressure control valve for providing a fluid pressure which is a substantially fixed value higher than a control pressure comprises a valve member slidable in a cylinder, one end of the cylinder communicating with a source of fluid pressure. The cylinder is provided with a circumferential groove in its periphery and the groove communicates with a drain and is arranged to be uncovered by the valve member as the latter is moved towards the other end of the cylinder by the fluid under pressure. A resilient means is located in the other end of the cylinder, and means is provided for generating a control pressure which is admitted to the other end of the cylinder. The arrangement is such that the valve member will move to control the pressure in the one end of the cylinder to a value proportional to the control pressure plus a substantially fixed value determined by the resilient means.</p> |
