The falling film evaporator is a kind of high efficiency evaporation equipment, it is also a thin film evaporator which include rising film evaporator and scraper film evaporator. Thin film evaporator has obvious advantages and is widely used in chemical industry, light industry and food processing industry to concentrating the liquid. The structure of falling film evaporator is quite simple, just combined with a heat exchanger and a film distributor. But it has an obvious difference between normal exchanger, the shell side is heating fluid, tube side is evaporated material. The materials in the falling film evaporator tube side are transfered from the top of the heat exchanger tube, with its own gravity to the downstream along the tube in the heat exchanger tube, and should be distributed by the film-distributor before be sent to the heat exchanger. So the materials will be film state in the heat exchanger, the water will be evaporated in the process of downstream and t...