The freeze dryer is composed of a refrigeration system, a vacuum system, a heating system, and an electrical instrument control system. The main components of the freeze dryer are drying box, condenser, refrigeration unit, vacuum pump, heating/cooling device, etc. The working principle of the freeze dryer is to freeze the dried items to below the triple point temperature, and then directly sublime the solid water (ice) in the items into water vapor under vacuum conditions, remove them from the items, and dry the items . After pre-processing, the materials are sent to the quick-freezing warehouse for freezing, then sent to the drying warehouse for sublimation and dehydration, and then packaged in the post-processing workshop. The vacuum system establishes low-pressure conditions for the sublimation drying chamber, the heating system provides sublimation latent heat to the material, and the refrigeration system provides the required cold energy to the cold trap and the drying chamber.

　　Freeze dryer is a technology that uses the principle of sublimation to dry. It is a process in which the dried material is quickly frozen at a low temperature, and then in a suitable vacuum environment, the frozen water molecules are directly sublimated into a process of water vapor escape. The product obtained by freeze-drying is called a lyophilized product.

　　The substance is always at a low temperature (frozen state) before drying, and ice crystals are evenly distributed in the substance. The sublimation process will not be concentrated due to dehydration, and avoid side effects such as foaming and oxidation caused by water vapor. The dry substance is porous in the form of a dry sponge, the volume is basically unchanged, and it is easily dissolved in water to restore its original shape. To the greatest extent, prevent the physical, chemical and biological denaturation of dry substances.

　　In recent years, continuous vacuum freeze dryers have been explored and used at home and abroad. The characteristic of the continuous freeze dryer is that it is suitable for the production of products with a single variety, large output and sufficient raw materials, and is especially suitable for the production of slurry and granular products. Continuous equipment is easy to realize automatic control, simplifies manual operation and management, and its main disadvantage is high cost.

　　With the end of GMP certification, domestically produced excellent pharmaceutical freeze dryers have entered the modernization stage, with complete functions, reliable work, stable performance, and can achieve online cleaning (CIP) or steam sterilization (SIP), and various technical indicators It can meet the needs of freeze-drying production of biological products and pharmaceuticals. In order to ensure the quality and energy saving of freeze-dried products, a combination freeze-drying equipment that combines freeze-drying equipment with other drying equipment, such as spray freeze-drying equipment, is often used.