Butterfly Valve of Rubber Seal a.Ozone and chemical resistance b.High temperature resistance Double Flange Butterfly Valve: SizeDN40 - ... , check valves, gate valves and so on with the materials of ductile iron, carbon steel, stainless steel to order. Our products ... are designed and manufactured in accordance with the standards of GB, ASME, ANSI, API, BS, DIN, JIS etc. Butterfly Valve of Rubber Seal