Rotary film evaporating apparatus

Claim 1

A rotary film evaporating apparatus comprising: a vertical cylindrical housing subdivided vertically into a plurality of intercommunicating sections; a heating jacket on the side wall of said housing at each said section; a central shaft mounted for rotation within said housing; hollow spraying drums concentrically mounted on said shaft in each one of said sections; longitudinal bars defining the side wall of each said spraying drum, said bars being generally S-shaped in cross-section and arranged so that the longitudinal outer edges of said bars extend into the indented portions of the adjacent ones of said bars, defining therewith labyrinth-like passsages for a vapor; the portions of said bars which are the most remote from said shaft having apertures made therethrough for passage of a liquid; means for supplying a liquid product to be evaporated into the topmost portion of said housing; means for withdrawing a concentrate from the bottom part of said housing; means for withdrawing the vapor from the internal space of said housing; means for collecting the evaporating liquid flowing down the wall of said housing within an upper one of said sections and for directing it into said spraying drum of the underlying one of said sections, said last-mentioned means being located intermediate the adjacent pairs of said sections.