... , tongue and groove, rubber ring joint face, the lens surface and the diaphragm welded surfacee, the Soviet Union ... public diameter: 6 ~ 4000mm c, Flange structure type: welding, socket welding, threaded connection, loose, butt weld and blind flange d, ... Integral flange Unit flange a, threaded flange b, welding flange, welding neck flange, welding neck flange, socket weld flange with neck , slipon ...