Vacuum dryer is through the smoke to pack the air inside the container after the desired vacuum, removal equipment parts water in a container. Drying time under vacuum in tank, jacketed pass hot water (or steam, heat conducting oil) heating, with the tank low speed rotation, the material in the tank up and down, inside and outside, "diamond trail" campaign and absorbing the evaporation, water vapour through the vacuum line continuous discharge, reached for drying purposes. In the dry mixture at the same time, built-in spray according to customer requirements, filtering, grinding device can achieve its multifunctional operations.