... , petroleum, power plants, light industry, textile, metallurgical industrial production. pneumatic diaphragm double-seated control valveMain parts materials: Valve body, valve cover ... PTFEGasket: Rubber,, graphite spiral wound gasket Membrane covered: A3 1Cr18Ni9TICorrugated Diaphragm: NBR folder enhanced polyester fabric Spring: 60Si2Mn Stem, putting: 2Cr13 ...