... edge loose type, Butt weld loop loose type, Butt weld, Joint type with neck threaded, Integral type and Blind flange. d ... : flat, raised face,male and female, tongue and groove, rubber ring joint face, the lens surface and the diaphragm welded surfacee, the ... surface: flat, raised face, convex face, tongue and groove, ring joint faceFlange production standard Chinese Standard:GB/T9112-2000(GB9113.1 ...