| 摘要 |
<p>There is disclosed a pilot operated valve which includes a valve body (1), a main valve having a main valve member (13) controlling fluid communication between an inlet port (14) and an outlet port (3), a pilot valve (2) including a vent passage sensing downstream pressure to open and close the main vlave member (13) as the sensed pressure is above or below a predetermined pressure, and selectively operable override means (16) to suspend pilot operation of the valve. The override means may be means to occlude the vent passage (10) and thus close the main valve, means to open the vent passage (10) to atmosphere and thus open the main valve, or means to bypass the main valve.</p> |
