초록 ▼

A microporous filter system comprises two types of hydrophilic, microporous filter media operating in series. The two filter media have opposite zeta potentials with the upstream or first filter medium preferably having the positive zeta potential and the downstream or second filter having the negat

A microporous filter system comprises two types of hydrophilic, microporous filter media operating in series. The two filter media have opposite zeta potentials with the upstream or first filter medium preferably having the positive zeta potential and the downstream or second filter having the negative zeta potential. The first filter medium typically has an absolute pore rating of from about 0.1 to about 1.0 micrometer and the second or downstream filter medium typically has an absolute pore rating of from about 0.02 to about 0.1 micrometer. The downstream or second filter has a finer absolute pore rating than the upstream or first filter. Fluids contaminated with ultrafine particles can be purified with an essentially absolute efficiency to remove 99.99 percent or more of the particulate matter in the contaminated fluid. The filter system finds particular use in the preparation of ultrapure effluent water of near theoretical resistivity and in the removal of bacteria and endotoxins to form sterile fluids.

대표청구항 ▼

A process for the filtration of a contaminated fluid comprising ultrafine particulate material with particle sizes in the range of from about 0.001 to about 10 micrometers said process comprising: (a) passing said fluid through a first filter medium comprised of a surface modified, hydrophilic, micr

A process for the filtration of a contaminated fluid comprising ultrafine particulate material with particle sizes in the range of from about 0.001 to about 10 micrometers said process comprising: (a) passing said fluid through a first filter medium comprised of a surface modified, hydrophilic, microporous member, said first filter medium further characterized by (i) an absolute pore rating in the range of from about 0.05 to about 1.0 micrometer and (ii) a positive zeta potential, to remove electronegatively charged particulate matter from said fluid; and (b) then passing said fluid through a second filter medium comprised of a hydrophilic, microporous member, said second filter medium further characterized by (1) an absolute pore rating finer than that of said first filter membrane and in the range of from about 0.01 to about 0.1 micrometer and (ii) a negative zeta potential, to form a filtrate substantially free of (1) both electronegatively and electropositively charged particulate matter, (2) bacteria and endotoxins, and (3) particulate matter greater in size than the absolute pore rating of said second filter medium.