| 摘要 |
This disclosure is directed to a dump valve. In the preferred and illustrated embodiment, the dump valve incorporates a valve operator and comprises a valve body having a side located port for admission of high pressure fluid and an axial outlet. The valve operator powers an elongate push rod which passes through an axial passage in the body and supports a hard metal valve element at the tip which is profiled to fit against a valve seat, blocking flow in the axially located passage. Additionally, it incorporates a second seat which is formed of a shaped inner valve of resilient material. This comprises a second valve element. The two valve elements collectively seal the passage. This is particularly helpful in that a hard trimmed, primary shutoff mechanism is first provided incorporating the hard trimmed valve element and seat, and a second soft trimmed valve element and seat cooperates with it. The hard trim valve must seat first before the rubber plug is expanded.
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