FIELD: forming foam from liquid and gaseous phases; circulation of foam in unit and cleaning unit due by circulating foam. SUBSTANCE: foam is formed due to suction of respective liquid phase and gaseous phase through porous lining. Circulation is ensured by forming reduced pressure after second end of unit. Cleaning the unit is effected by means of cleaning foam produced by said method. Foam generating unit has chamber with porous lining between inlet and outlet holes and device for sucking liquid and gas through porous lining. Foam generating unit includes foam generating system, connector and liquid and gas sucking device. EFFECT: possibility of generation and circulation of foam at pressures equal to or below atmospheric pressure. 6 cl, 6 dwg, 4 tbl, 4 ex
