... valve a.Ozone and chemical resistance b.High temperature resistance c. Excellent weather and water resistance Double Flange Butterfly Valve: ... power, petroleum, petrochemical, heat supply, shipbuilding, medicine and metallurgy industries.Suitable Medium:Water, sewage,sea water, air ... and manufactured in accordance with the standards of GB, ASME, ANSI, API, BS, DIN, JIS etc. various high quality Double ...