Drying advantages of freeze dryer

2021-02-01 09:55:07
Drying advantages of freeze dryer
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 item into water vapor under vacuum conditions, and remove it from the item to make the item dry. 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 of the freeze dryer 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. The freeze dryer adopts high-efficiency radiant heating, and the material is heated evenly; it adopts high-efficiency water traps and can realize rapid defrost; adopts high-efficiency vacuum unit, and can realize oil-water separation; adopts parallel centralized refrigeration system, multi-channel cooling on demand, The conditions are stable and energy-saving; artificial intelligence control is adopted, with high control precision and convenient operation.

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, you should have a more comprehensive understanding of freeze drying theory and technology. The freeze drying process of the freeze dryer includes three stages: pre-freezing, sublimation and re-freezing. Reasonably and effectively shorten the freeze drying cycle has obvious economic value in industrial production.

The dried products generally have the problems of reduced volume and hard texture. Most of the volatile components will be lost. Some heat-sensitive materials will be denatured and deactivated, and some materials may even be oxidized. Therefore, there is a big difference in the properties of the dried product compared to the one before drying. The freeze drying method is basically carried out below 0°C, that is, the product is carried out in a frozen state. Only when the residual moisture content of the product is reduced in the later stage, the product is allowed to rise to a temperature above 0°C, but generally does not exceed 40°C. Under vacuum conditions, when the water vapor is directly sublimated, the medicine remains in the frozen ice shelf, forming a sponge-like loose porous structure, so the volume of the freeze dryer is almost unchanged after drying. Before using again, just add water for injection and it will dissolve immediately.

Advantages of freeze dryer:

1. Many heat-sensitive substances will not be denatured or inactivated;

2. When drying at low temperature, some volatile components in the substance lose little;

3. During the freeze drying process of the freeze dryer, the growth of microorganisms and the action of enzymes cannot proceed, so the original properties can be maintained;

4. Since the drying is carried out in a frozen state, the volume is almost unchanged, the original structure is maintained, and no concentration phenomenon occurs;

5. Since the moisture in the material exists in the form of ice crystals after pre-freezing, the dissolved inorganic salt substances originally dissolved in water are evenly distributed among the materials;

6. The dried material of the freeze dryer is loose, porous, and sponge-like. It dissolves quickly and completely after adding water, and restores its original properties almost immediately;

7. Since the drying is carried out under vacuum, there is very little oxygen, so some easily oxidized substances are protected by the freeze dryer.