REGENERATION OF AIR

From Big Medical Encyclopedia

REGENERATION OF AIR (late lat. regeneratio revival, resuming) — process of recovery of composition of air or the gas mixtures intended for breath with their cleaning of waste products of the person and technological emissions. Sometimes include not only purification of air, but also conditioning in this concept (see. Air conditioning ).

The river of century for the purpose of ensuring breath is carried out in the pressurized objects — flight cabins, compartments of spacecrafts, manned compartments of submarines, deep-water diving complexes, bathyscaphes and bathyspheres, hydrostats and submersibles, underground constructions, and also in individual space suits (see) and respiratory devices (see. Oxygen and respiratory equipment ). For R. for century the technological life support system providing removal of carbon dioxide gas, carbon monoxide, other harmful impurity, smells and excess of moisture, attemperation and speeds of exchange of gases, enrichment of oxygen and emergency supply of gases, and if necessary dusting and pathogenic microflora is used (see the scheme).

Scheme of a standard revitalization system of air and gas mixture

Distinguish individual and collective revitalization systems of the closed and half-closed cycle. Individual revitalization systems are applied preferential in the individual isolating respiratory devices of willows space suits, and also in subsystems of emergency air delivery and gas mixture to individual breath. In loop systems of R. it is carried out on a complete cycle, including recovery of all initial parameters of a gaseous fluid; in semiclosed circuits from the reserve stock provided in a life support system.

At design of system P. of century as initial use fi-ziol. parameters of the «standard» person (tab).

Removal of carbon dioxide gas is carried out chemical, physical. - chemical or biol. in the way. The most widespread chemical way of removal of carbon dioxide gas is absorption by its sorbents disposable — natroncalc, hydrates of lithium oxide, calcium and barium (see. Sorption ). So, 1 kg of slaked lime or the chemical absorber of limy (CAL) is capable to connect apprx. 150 l of carbon dioxide gas. Peroxides and superoxides of alkali metals not only delete carbonic acid, but also generate oxygen (see), napr, the oxylitas consisting of sodium peroxide and superoxide of potassium absorbs excess of carbonic acid and water and emits oxygen:

Na 2 O 2 + 2KO 2 + 2CO 2 = Na 2 CO 3 + To 2 CO 3 + 2O 2 + 98 kcal

During the use of lithium hydroxide (caustic alkali) in the absorption block shall be filter (see), protecting from hit of a sorbent on skin, mucous and a cornea of an eye. For safety at storage and use of peroxides and superoxides of metals their isolation from water and active coal is provided in a revitalization system.

Physical. - chemical purification of air of carbon dioxide gas is carried out by means of the regenerated firm sorbents molecular sieves (see). As an absorber zeolite — alyuminosilikat alkali metals can be used. Zeolite after heating is recovered and can be reused.

Physical. methods of purification of air of carbon dioxide gas of other harmful impurity and moisture are based, as a rule, on use of the cryogenic equipment. At biol. to purification of air of carbon dioxide gas live organisms are used (e.g., a chlorella), to-rye absorb carbon dioxide and in the course of photosynthesis emit oxygen.

Carbon monoxide (see) collects in the pressurized compartments as a result of life activity of the person, and also incomplete combustion of oils and other substances in technical nodes of a life support system. Gopkalitovy filters — the oxidizers consisting of mix of copper oxide and manganese dioxide are used to cleaning of it. The preheated air comes into contact with catalyst (see), at presence to-rogo carbon monoxide and hydrogen are oxidized oxygen of air to carbon dioxide gas and water.

For purification of air of harmful impurity and smells it is used active coal (see). Excess of moisture is deleted with method of condensation on the cooled surface, and also by means of silica gel, aluminogel and other dry gels (see).

Process of regeneration provides recovery of concentration of oxygen, temperature and humidity after cleaning of a gaseous fluid of carbon dioxide gas and carbon monoxide, smells, harmful impurity and excess of moisture. For recovery of the oxygen content its missing part is generated one of the specified chemical ways or filled up from a reserve stock in a life support system, to-ry it is stored in gas bottles or vessels of the Dewar. For enrichment of air and gas mixtures oxygen use also electrolysis of water and water vapors with an ion-exchange membrane and sulfate electrolyte and an asbestos matrix. The dosed supply of oxygen for enrichment of air and gas mixtures is carried out under control gas analyzers (see). In the individual isolating devices the dosed tanks are applied to this purpose, to-rye fill automatically according to frequency rate of exchange of volume of gases.

Heating and moistening of air and gas mixtures before receipt in the pressurized compartment is carried out by means of humidifiers and heatelectric heaters.

For safety of operation of revitalization systems by means of special devices periodic or constant control behind composition of gas mixtures, content in them of microimpurity and behind indicators of a microclimate is conducted. In sovr. life support systems these devices are connected with other blocks and form the uniform automated system.

At disturbance of a revitalization system in the pressurized compartments accumulation of waste products can become the reason of poisoning with carbon dioxide gas, hypoxias, poisonings with alkalis, and at the fires and accidents — the carbon monoxide, harmful impurity, toxicants emitted by finishing synthetics at their burning. Marginal parameters of a microclimate are developed for prevention of diseases and poisonings, the structure of gas components and harmful impurity for breath in the pressurized compartments and the isolating regenerative devices is defined. Concentration of carbon dioxide gas shall not exceed 1%, oxygen there have to be not less than 17% and no more than 25%, carbon monoxide no more than 20 mg/m 3 , total hydrocarbons no more than 300 mg/m 3 .

Control for a dignity. - a gigabyte. working conditions in the pressurized compartments and the isolating regenerative respiratory devices it is carried out by medical staff.

&Tablitsa.Nbsp; PHYSIOLOGICAL PARAMETERS of the «STANDARD» PERSON FOR DESIGN of REVITALIZATION SYSTEMS of AIR





Bibliography: Alatyrtsev A. A. and d river. Engineering reference book on the space equipment, M., 1969; Dubinin M. M. Physical and chemical bases of the sorption equipment, M. — JI., 1935; Uniform safety rules of work at diving works, M., 1980; Encyclopaedic dictionary of military medicine, t. 4, Art. 1078, M., 1948.


G. I. Kurenkov.

Яндекс.Метрика