~Bolt cover,structure of flip-chip balanceable pressure and light on/off operation.An oil grove is set between valves body and seal surface,which may infuse the seal grease to increase the seal capability.
Design and Manufacture: API 599,API 6D
Face to face(end to end): API B 16.10
Flanged connection: ANSI B16.5
Butt welded end: ANSI B16.25
Test and inspection: API 598,API 6D