| 摘要 |
A pilot valve (26) for operating a pressure relief valve (10) having a pressure chamber (62) always in communication with system pressure formed at the upper end of a channel with a sensing piston (38) acted on by system pressure and a compression spring (44). A sleeve assembly, slideable in the channel and connected to sensing piston, has a stem assembly slideable therein to form a pilot dome chamber (73); the two assemblies forming an inlet valve for directing system pressure to the pilot dome chamber. An inlet valve spring (82) biases the inlet valve closed and an exhaust valve either ports of dome chamber to exhaust or isolates the dome chamber therefrom. |
