DT673 pneumatic clamp-on elastic hard seal butterfly valve can be used in the field requirements of narrow space and short pipeline distance. The pneumatic pinch butterfly valve adopts a "U" stainless steel sealing ring, the precision elastic sealing ring and the polished butterfly plate three-dimensional eccentric contact, to solve the traditional eccentric butterfly valve in the opening and closing 0 ° ~ 10 ° instant sealing surface is still in the sliding contact friction drawback, to achieve the butterfly plate in the opening instant sealing surface separation, close contact sealing effect, to achieve the purpose of prolonging service life, sealing performance is the best. Pneumatic butterfly valves are widely used in pipelines of corrosive media such as metallurgy, electric power, petroleum, chemical industry, air, gas, combustible gas and water supply and drainage, and are the best devices for regulating flow and cutting off fluids.