The production process of freeze dryer mainly includes the following steps: pre-freezing, sublimation drying and analytical drying.
Pre-freezing: Place the material to be processed in a low temperature environment so that the internal water quickly freezes into ice crystals. This step is crucial because it ensures that the water in the material exists in solid form, which is convenient for subsequent direct sublimation. Through precise temperature control, the material is quickly frozen to below the freezing point in a short time, forming a tiny ice crystal structure, thereby reducing the deformation and damage of the material during the drying process.
Sublimation drying: Under vacuum conditions, the ice crystals on the surface of the material are directly sublimated from solid to gas by heating and are pumped away by the vacuum system. The pressure in the freeze dryer is reduced to an extremely low level, so that the ice crystals can be directly sublimated into water vapor without passing through the liquid water stage. This process avoids the problems of volume expansion and structural damage caused by the presence of liquid water in the material.
Analytical drying: After sublimation drying, the temperature is further increased to cause the bound water remaining in the material to evaporate and be removed. This step can further reduce the residual moisture in the material and achieve the final drying effect.
The core technology and equipment of the freeze dryer include refrigeration system, heating system, vacuum system, control system and drying chamber. All parts work together to ensure the efficiency and stability of the drying process. For example, the technological innovation of modern vacuum freeze dryers is reflected in three aspects: intelligent control system, energy-saving design and modular structure. The advanced PID control system can monitor the material temperature, vacuum degree and residual moisture in real time, automatically adjust the heating power and cold trap temperature, and ensure the accuracy and stability of process parameters. In addition, the new heat pump auxiliary refrigeration system can reduce energy consumption by more than 30% compared with traditional compressor refrigeration, and the modular design allows users to flexibly combine the freeze-drying area according to production requirements.
