Working principle:
Pure water has the highest evaporation speed under boiling condition. Under normal
pressure, pure water starts to boil at the temperature of 100oC, under
vacuum condition, as vapor pressure in the system is lower than that of material
surface, boiling point of water is under 100oC. For example, when
surface is at 0.7MPa, water will boil at the temperature of 70oC, the
higher the vacuum, the lower the boiling point. In the vacuum drier, evaporated
water can be removed quickly under the vacuum system, therefore, this drier has
larger drying capability, although it is under lower operation temperature.

Material is under static conditions during operation of the equipment, which is good
for keeping initial status of materials, and intermittent operation can adjust
process conditions at any time.