Importance

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Abstract

Disclosed is an in-service test valve and system. The in-service test valve includes a body having a first chamber with a relatively small diameter bore and second chamber axially spaced apart from the first chamber and having a relatively large diameter bore. An imperforate shuttle is slidingly mounted in the valve body and includes a first piston slidingly sealingly mounted in the first chamber bore and a second piston slidingly sealingly mounted in the second chamber bore. An in-service inlet is provided in the valve body for introducing in-service pressure into the first chamber to apply sensing pressure to the first piston and urge the shuttle toward the second chamber. A test inlet is provided for introducing test pressure into the second chamber to apply test pressure to the second piston to urge the shuttle in the direction of the first chamber. A check valve is provided in the valve body for allowing communication of test pressure to the first chamber when test pressure is greater than first chamber pressure. A valve operated by the shuttle is provided for isolating the in-service inlet from the first chamber when test pressure is applied. An outlet is provided in the valve body for communicating pressure within the first chamber exterior of the valve.

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First Claim