| 摘要 |
<p>A pilot operator and a relief valve are provided in the same housing. The pilot-operating mechanism is contained partially within the main closure element (34) of the valve and partially within the valve cap. Inlet pressure to the valve is communicated to the pilot via an access passage (39) extending through the main closure element (34). In response to high-pressure flow from the inlet, a pilot piston moves a spacer rod (48) through the passage (39) and into engagement with a spring-loaded vent closure. The piston induced movement of the rod (48) opens the vent to relieve the pressure behind the main closure element (34), which in turn permits the main closure element (34) to open and relieve the inlet pressure through the valve outlet. Opening of the main closure element (34) terminates flow through the access passage (39).</p> |
