FIELD: production of commercial gaseous and liquid oxygen and other gases; oxygen stations of metallurgical, chemical and engineering plants. SUBSTANCE: method consists in cleaning the air from dust and mechanical impurities, compression of air in compressor stages, cleaning the compressed air from carbon dioxide, drying and cleaning it from hydrocarbons, liquefaction and rectification of air for separation and accumulation of separated gases; at least part of air before separation in above-mentioned plant is subjected to preliminary separation in one vortex device for separation of media at heterogeneous field of densities and at different molecular mass of components ensuring increased content of oxygen, for example at air-separating plant inlet. Vortex device of combined air-separating unit includes flow swirler; second flow swirler is mounted on inlet section of vortex pipe at some distance from flow swirler. One outlet of vortex device is brought in communication with inlet of air-separating plant. EFFECT: reduced power requirements at improved quality of air separation; enhanced operational efficiency of air-separating plant. 18 cl, 12 dwg
