BigPatents India

The invention concerns a downward flow evaporator, with internal condensation, comprising at least a vertical evaporator tube (12) housed in a casing (10), and a dispensing vessel (16) arranged above the evaporator tube (12), from which a liquid to be evaporated can be brought to the evaporator tube (12), producing a downward flowing film in its tubular housing. In order to ensure condensation of the vapour formed during evaporation of the liquid, there is provided a heat-exchanging device (18, 52), whereof the condensation surfaces consist, in accordance with the invention, of at least a condensation tube (18) arranged vertically in the evaporation tube (12), and having substantially the same axis. Above said pair of tubes (12, 13) are housed reception means (20, 22) in the casing (10), capable of collecting separately, the non-evaporated liquid concentrate, flowing from the evaporator tube (12), and the condensed liquid distillate, flowing from the condensation tube (18). (FIG.1).