Abstract: The invention relates to a heat exchange element (1) which is made up of a bag of a film material, such as plastic film, and to a heat exchanger made up of such heat exchange elements, the heat exchanger being suitable, for example, for the evaporation of effluents which contain solid matter, such as effluents from bleaching. The transfer of heat takes place in the bags (1) from a vapor condensing in the interior (3) of the bags to a liquid evaporating on their exterior surfaces (2). The forming evaporated vapor may be recycled via a compressor to the interior of the bags as heating vapor so that the heat exchanger will function as a distillation apparatus.

Abstract: A liquid distributor for distributing liquid over the heat transfer surface of an evaporator includes a channel array including one or more supply channels and downwardly deviating distribution channels. Each distribution channel has a step-shaped expansion located downstream with respect to the supply channel and connecting therewith via a sharp point, restricting the liquid suction created in the distribution channel. Sharp points provided in the supply channel or channels further restrict the liquid suction.

Abstract: A liquid distributor in an evaporator, intended in particular for the evaporation treatment of liquid suspensions which contain fibers or other such solid ingredients. The distributor comprises, located at the upper end of the heat exchange surface, a transverse frame, liquid conduits disposed therein distributing the liquid over the entire width of the heat exchange surface. According to the invention the liquid conduits are made up of feed conduits slanted obliquely downwards and of distribution conduits branching out therefrom and leading to the heat exchange surface. At the branching points of the conduits their wall surfaces on the downstream side with respect to the feed flow are rounded into curved dividing surfaces by means of which the dividing of the flow is carried out.

Abstract: The invention relates to a heat exchanger wherein the heating vapor is fed onto heat exchange surfaces of membrane material from a vapor distributor, the vapor distributor having parallel conduits for directing vapor over the entire width of the surfaces. According to the invention the vapor distributor is made up of two opposing wall elements which are fastened to each other by means of projections in one element and corresponding recesses in the other element. The upper end of the membrane constituting the heat exchange surface is locked between the projections and recesses that are fastened to each other. Thus, pleats are produced in the membrane as an expansion leeway for the vapor space delimited by the membrane.