Detailed explanation of freeze dryer
Freeze-drying is a drying technology using the principle of sublimation. It is a process in which the dried material is quickly frozen at low temperature, and then in a suitable vacuum environment, the frozen water molecules are directly sublimated into water vapor to escape. The product obtained by freeze-drying is called a lyophilizer, and the process is called lyophilization. The substance is always at a low temperature (frozen state) before drying, and the ice crystals are evenly distributed in the substance. The sublimation process will not cause condensation 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 soluble in water and returns to its original state. Physicochemical and biological denaturation of dry substances is prevented to the greatest extent possible. The freeze dryer is composed of a refrigeration system, a vacuum system, a heating system, and an electrical instrument control system. The main components are drying box, condenser, refrigeration unit, vacuum pump, heating/cooling device, etc. Its working principle is to freeze the item to be dried to below the triple point temperature, and then directly sublime the solid water (ice) in the item into water vapor under vacuum conditions, and remove it from the item to dry the item. After pre-processing, the materials are sent to the quick-freezing bin for freezing, then sent to the drying bin for sublimation and dehydration, and then packed in the post-processing workshop. The vacuum system establishes low pressure conditions for the sublimation drying chamber, the heating system provides latent heat of sublimation to the material, and the refrigeration system provides the required cooling capacity to the cold trap and drying chamber. The equipment adopts high-efficiency radiation heating, and the material is heated evenly; it adopts high-efficiency water-trapping cold trap, which can realize rapid defrosting; adopts high-efficiency vacuum unit, which can realize oil-water separation; adopts parallel centralized refrigeration system, multi-channel on-demand cooling, working conditions It is stable and beneficial to energy saving; artificial intelligence control is adopted, with high control precision and convenient operation. Xinyu Instrument Network The quality requirements for freeze-dried products are: unchanged biological activity, uniform appearance and color, full shape, firm structure, fast dissolution rate, and low residual moisture. To obtain high-quality products, one should have a more comprehensive understanding of the theory and process of freeze-drying. The lyophilization process includes three stages: pre-freezing, sublimation and re-lyophilization. Reasonably and effectively shortening the freeze-drying cycle has obvious economic value in industrial production.
