Small vacuum freezing dryer drying process, by dry material need heat is mainly composed of heating plate at the bottom of the screen, conduction.
in the sublimation stage, the beginning of the vessel wall and heat transfer between frozen material is very effective.
Soon, however, a layer of ice, and dry area of the porous formed.
Then the container wall between the material and produce the corresponding temperature ladder.
To have dry area of the thermal conductivity fall in ice cores, the rise of temperature if ice core temperature rises to above freezing point temperature, the material began to thaw.
This is particularly used to uneven material and thickness of multilayer structure.
Therefore must be precisely controlled the drying stage of the heat supply, temperature and pressure.
