Vacuum low-temperature evaporating crystallizer

The utility model relates to a vacuum low-temperature evaporating crystallizer. The vacuum low-temperature evaporating crystallizer is of an integrated structure in which a condenser is directly connected with the top of an evaporator. Cooling water in the condenser passes through a tube side, secondary steam passes through a shell side, spiral gradually-changing variable-interval secondary steam guiding baffle plates are arranged in the shell side, namely the spiral interval of the upper part is large and the interval of the lower part is small, an electromotor arranged at the bottom of a central flow guiding cylinder is used for directly driving streamlined impellers for stirring circulation, and the rotating speed is regulated by a frequency converter.