From Big Medical Encyclopedia

FILTERING (a synonym filtering) — process of mechanical division of liquid or gaseous disperse systems by means of the porous partitions capable to pass a dispersion medium and to detain particles, the sizes to-rykh exceed diameter of a time of a partition. T. it is widely used in a dignity. - a gigabyte., biochemical, mikrobiol. and clinical diagnostic laboratories, in pharmakol., food and other industries.

Passed through a filtering partition — the filter (see Filters) — liquid is called a filtrate. For acceleration F. create pressure difference between the different parties of the filter, carrying out process under supertension, at high depression or in the centrifuge. Choice of the filter and way F. is defined by the size and a particle shape of a dispersed phase or the nature of a dispersion medium. The filtered sample shall not enter chemical reaction with material of the filter, volatile liquids cannot be filtered in vacuum; viscous liquids filter under pressure or at an elevated temperature for reduction vyazkost and (see). At department of the solid matters having low melting temperature, T. carry out during the cooling.

Speed F. depends on density of the filter and size of a filtering surface and is defined by the so-called filtering ability, i.e. amount of the liquid (or gas) in ml passing in 1 sec. through

1 cm2 of a filtering surface at difference (gradient) of pressure in 1 cm w.g.

See also Ultrafiltration. Bibliography: At and V. A k. Filtering, Theory and practice of division of suspensions, M., 1971; Kazakova I. A. both M about t and N and G. M. Filter mediums for air sterilization, M., 1974; Rudenko L. I. and With to l I r

V. T. Properties of supporting filter mediums, Chemistry and technology of fuels and oils, No. 10, page 12, 1981; Sh and the blvd. I e in B. F. and P and in l about in with to and I am E. I. Ceramic-metal filter elements, Reference book, M., 1972; Sh at sh to the island of E. II., Gold navel N. K. and Sherman V. S. The automatic control of straining action, in book: Automatic control and instrumentations in industrially

st of the main chemistry, under the editorship of V. S. Sherman, page 115, L., 1975; Freshwa

FILTERS 325 ter D. Page A new approach to the design of filtration systems, Filtration and Separation, v. 13, p. 244, 1976; 6

1 1 i n-g e r S. Neue Systeme zur Steril-oder Keimarm-Filtration von Roh-und Zwischen-produkten in der Kosmetika-Industrie, Sei-fen, - 01e, - Fette, Wachse, Bd98, S. 393, 1972; H e p p 1 e J. R. Filtration in the manufacture of vaccines and anti-sera, Filtration and Separation, v. 9, p. 283, 1972.

M. G. Karasyova.