| 摘要 |
<p>PCT No. PCT/GB93/01110 Sec. 371 Date Mar. 13, 1995 Sec. 102(e) Date Mar. 13, 1995 PCT Filed May 27, 1993 PCT Pub. No. WO94/00709 PCT Pub. Date Jan. 6, 1994.A pressure relief valve includes an apertured ball valve element which is spring loaded and is rotatably and axially mounted in the valve bore so that when an over pressure situation arises fluid forces the ball axially off the valve seat against the force of a spring and causes the ball valve to rotate such that the aperture in the ball valve connects the inlet bore and outlet bore of the valve housing so that fluid can flow through the pressure relief valve. When pressure at the inlet falls beneath a predetermined value, the spring forces the ball to rotate and move back against the valve seat, thus closing the valve. With this arrangement there is minimal pressure exerted on the valve housing and the valve will operate with a back pressure up to 50% of the inlet pressure. This means that much smaller bore outlet piping can be used with a savings in weight and, consequently, cost.</p> |
