US Patent 7063304 Extended stroke valve and diaphragm

An extended stroke poppet valve particularly suited for handling caustic fluids and having features enabling an extended service life for the valve. The valve includes a two part primary diaphragm assembly with a wetted diaphragm made from highly fatigue resistant fluoropolymer material, and a diaphragm backer made from high strength fluoropolymer material designed to withstand the high stress loads imposed by an extended valve stroke. The combination of these two layers in a single primary diaphragm assembly yields a highly durable, caustic chemical resistant, diaphragm capable of use in a long stroke poppet valve and having a relatively long service life.