Laminated microporous fluorocarbon membrane and fluorocarbon filter cartridge using same

A microporous polyfluorocarbon filter cartridge comprising:

• a filter cartridge body formed of polyfluorocarbon and having an inlet and an outlet,
• a polyfluorocarbon filter membrane assembly disposed in said cartridge body so that fluid moving from said inlet to said outlet must pass therethrough, said membrane assembly having:
• a microporous, integral, composite polyfluorocarbon membrane made up of three or more sheets of aggregated microporous fluorocarbon polymer, said polymer having in the unaggregated state an average individual particle diameter of not more than about 0.3.mu.m, said membrane having a fine porosity pore-containing microporous fluorocarbon polymer sheet having an average pore diameter of from about 0.01.mu.m to about 1.mu.m integrally formed between a first sheet or sheets of larger porosity microporous fluorocarbon polymer and a second sheet or sheets of larger porosity microporous fluorocarbon polymer, at least one of said first and second sheets having an average pore diameter of from about 1.mu.m to about 10.mu.m and,
• a polyfluorocarbon mesh support secured in said cartridge body so as to support said membrane against the pressure of fluid flow through said cartridge body.