Method and apparatus for freeze drying

摘要

In the freeze drying method of the present invention, a predetermined amount of water is poured on the refrigerating/heating surface provided in the drying chamber, which surface is cooled to a temperature below 0 DEG C., so that an ice film is formed on the refrigerating/heating surface. After that, while the thus formed ice film is kept at a temperature below 0 DEG C., a liquid material is supplied to the surface of the ice film so that a frozen layer of the liquid material is formed on the surface of the ice film. Under such circumstances, a vacuum is produced in the drying chamber to conduct the freeze drying operation of the frozen material in a vacuum environment.