Sea water desalination apparatus

The invention discloses a sea water desalination apparatus, comprising a heater, a single-effect evaporator, a double-effect evaporator, a triple-effect evaporator, a water collector, a condenser and a sea water pump, wherein the single-effect evaporator is a first plate heat exchanger and both the double-effect evaporator and the triple-effect evaporator are second plate heat exchangers. In the apparatus provided by the invention, tubular heat exchangers are replaced with the plate heat exchangers, two media in the plate exchangers reversely flow, heat exchange efficiency is high, and thus an end temperature difference about 1 DEG C can be economically achieved; meanwhile, plates need not be too long, and compared with the tubular heat exchangers, the apparatus enables the effective reduction in size of the heat exchangers and thus enables the reduction in floor area of a sea water desalination multiple-effect evaporation system.