| 摘要 |
<p>A pilot (14) operated pressure relief valve (12) system having a modulating action. The pilot valve (14) is of the nonflowing type and comprises sleeve (80,82) and control stem (48,64,78) members translating within a channel (52). The sleeve member (80,82) comprises an exhaust valve (82) for relieving dome pressure on the relief valve (12) when lifted by the control stem (48,64,78). The control stem (48,64 78) translates in response to system pressure changes and comprises an inlet valve (78) co-operating with a seat (80) on the sleeve member (80,82) to form an inlet valve closable to isolate the dome (30) from the system pressure when the latter reaches a level predetermined in relation to a set pressure.</p> |
