The POREFLON Membrane Module uses POREFLON hollow fibers as the filter membrane. The membrane has a composite structure comprising an outer filter layer and an inner support layer, as shown in the Illustration of POREFLON Hollow Fiber Membrane.

The closely packed outer filter layer determines the pore size. The coarse inner support layer provides strength. Both are constructed of PTFE and are integrated. The double-layer structure of the hollow fiber membrane ensures that the POREFLON Membrane Module exhibits both high permeability and high strength.