| 摘要 |
The pilot operated relief valve includes 1st and 2nd pilot stages and a balanced main relief valve(7). A valve body(A) contains the stages and includes two inlet exhaust(12)(11) and test ports. A first stage poppet(18) co-acts with a first seat below a predetermined product pressure. A second stage plunger(28) has upper and lower ends and co-acts with second and third seats for first and second plunger positions. Product pressure, exceeding the predetermined valve, moves the poppet from the first to the second position and the plunger moves to the second position thereby isolating inlet port to prevent further product flow through the first seat.
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