Mainly consists of two parts, the heating chamber and the evaporation chamber. The heating chamber is provided with the heat required to evaporate the liquid, which causes the liquid to boil. The vapor generated in the heating chamber is provided with a large amount of liquid, and to the evaporation chamber of the larger space, the liquid is separated from the vapor by the action of the self condensation or the addition of the foam. Usually the foam remover is located at the top of the evaporation chamber. The evaporator is divided into 3 kinds according to the operating pressure, pressure, pressure and pressure. According to the solution in the evaporator of the movement situation is divided into: 1. Boiling solution in the heating chamber several times through the heating surface, such as a central circular tube, the suspension basket type, external heat type, Levine and forced circulation type etc.. Single pass type. Boiling solution in the heating chamber in a by heating the surface without circulation, discharged concentrated liquid, such as rising film type, falling film type, stirring film type and centrifugal film type. Direct contact type. Heating medium and solution direct contact heat transfer, such as submerged combustion evaporator. Evaporation device in the operation process, to consume a large amount of heating steam, in order to save heating steam, can use multiple effect evaporation device and steam re compression evaporator. Evaporator is widely used in chemical industry, light industry and other departments.