... seat with seal Polytetrafluoroethylene Lining Butterfly Valve(PTFE Lining Butterfly Valve)PTFE lined valve adopting the PTFE butterfly board to ... in the rotary base between the butterfly board and valve seat, therefore, the impact and beautiful outloo,reasonable ... sulfuric acid, hydrofluoric acid, phosphoric, chlorine, strong alkaline, aqua regia etc.a)Connection Type; Wafer type, Flange typeb) ...