... valves,ball valves,butterfly valves,diaphragm valves,mud valve ect.And it has complete inspection equipment, such ... T79.1~79.25.Pressure test of general valve: GB/T139276.Valve inspection and test: JB/T90927.Drivign manner: ... -tightening force applied to have inlet and outle dual-way sealed;and the open-close moment with ... the sealing face inlaid witn PTFE,so has dual seals of PTFE to metal and metal,the ...