includes filtration of fluids, gases & radiations; not for electrical or electronic filtering; filters: index FILTRATION / instrum but note MICROPORE FILTERS and AIR FILTERS are available

A process of separating particulate matter from a fluid, such as air or a liquid, by passing the fluid carrier through a medium that will not pass the particulates. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

70; FILTERS was see under FILTRATION 1970-74, was heading 1963-69