A. Specification: DN50-DN600 B. Characteristics: Pin-less; the valve stem has axial positioning device; the two end faces of valve seat are widened; no special-purpose flange is required; the end faces of valve seat are of tongue-and-groove structure, which could avoid deformation of valve port in case of clamping. C. Working pressure: 1.0/ 1.6MPa D. Materials Valve body: Cast iron/ ductile iron/ cast steel/ stainless steel Valve disc: Ductile iron/ bronze/ nylon/ ceramics/ stainless steel Sealing seat: Nitrile butadiene rubber (NBR) / ethylene propylene rubber (EPDM)/ fluorine rubber (VITON) silicone rubber (SEP)/ tetrafluoroethylene (PTFE)