The membrane stack consists of PTFE filter membrane and imported deflector layer, and possesses superior properties of oxidation-resistance and chemical-resistance. Its A type’s shell, central rod and end cover adopt PP material. Its B type’s end is made from high temperature resistance material with high temperature lining, and is usually applied to the site of rather high temperature. Its C type’s shell central rod and end cover adopts imported PTFE/PFA material with steel lining, and can be applied to the site of high temperature resistance.