From Big Medical Encyclopedia

DRYING — process of removal of gaseous, liquid or solid matters of the liquid added to them, is more often waters (dehydration).

It is widely applied in the chemical and food industry, in galenovo-pharm century. production, during the processing of medicinal vegetable raw materials etc. V. apply at different carrying out biochemical analyses, at conservation of a blood plasma and its separate fractions, fabrics to transplantation, at morfol, or gistokhy. studying of fabrics, during the receiving drugs for a submicroscopy etc. V. is used as supportive application at disinfection. Nek-ry species of microbes (stick of an influenza, meningokokk, gonokokk, cysts of a dysenteric amoeba, etc.) at V. quickly perish. Causative agents of a typhoid and paratyphus, a brucellosis, tuberculosis, diphtheria, natural smallpox, etc. stand V. for a long time. Disputes of microbes keep viability and virulence in the dried-up state for many years. The existing methods B.

chemical binding, or sorption is the cornerstone, of the deleted liquid, its evaporation at low, high temperatures or in vacuum during the heating (see. Evaporation ) or in the frozen state — freeze drying (see. Lyophilizing ).

Laboratories B. of gases make a transmission them through konts. sulfuric to - that, being in Tyshchenko, Dreksel or Woolf's bottles, through firm absorbers, napr, the calcinated Calcium chloratum, phosphoric anhydride, etc., to-rymi also fill absorption columns or special vessels.

Dehydration of liquids is carried out entering into them of hygroscopic substances — pieces of fused Calcium chloratum or caustic heat, the calcinated cuprous sulfate or calcium oxide, etc. At the same time the dehumidifier shall not interact with the dried-up liquid chemically. Final dehydration of many organic liquids is carried out by means of sodium metal.

Solids dry up by heating them in porcelain casseroles, in braziers in the open air or in drying ovens, keeping in the exsiccator over hygroscopic substances, usually over konts. a chamois to - that, the calcinated Calcium chloratum, caustic soda, phosphoric anhydride at elimination of water, over Calcium chloratum during the dealcoholizing, over paraffin during removal of ether, heating in vacuum exsiccators or vacuum drying ovens, heating by means of infrared beams.

Leads to noticeable change physical century. - chemical properties of substances, napr, temperatures of boiling and melting, conductivity, reactivity, etc. V. of the substances which are exposed even at moderate heating in the wet or dissolved condition of a denaturation and to other irreversible changes make by method of lyophilizing. The choice of a method and V.'s conditions depends on properties of the dried-up material and its subsequent appointment.

See also Dehydration .

Bibliography: Voskresensky P. I. Technology of laboratory works, M., 1973; Use of freezing — drying in biology, under the editorship of R. Harris, the lane with English, M., 1956, bibliogr.

V. P. Mishin.