Safety valve supply channel links inlet to outlet with inbuilt shut=off valve

摘要

The supply channel (2) has an inlet-facing (P) sector (42) between inlet and outlet (A) which is larger in flow section than the outlet-facing sector (43) and both sectors are served by a station (46, 47) taking static pressures in both sectors. These two static pressure readings are routed to a primary control (54) to load the opposing control faces (62, 63) of a primary control element (64), using the static pressure of the second sector to load the element in the closing direction. The switching response adjuster (68) forming part of control (54) uses its spring (67) to load the element in the closing direction. A vent channel (66) controlled by the element communicates with the main control chamber (18) which is limited by the shut-off strike face (35) as loaded by the fluid outlet pressure. The shut-off valve unit (5) is placed between the two channel (2) sectors. The channel sector (45) following sector forms the outlet proper and commands the same flow section as the first sector.