The principle of a freeze dryer is a technical method of preliminarily freezing an aqueous article and then sublimating its water under vacuum to obtain a dried article. The freeze-dried articles are easy to store for a long time, and can be restored to the state before lyophilization and retain the original biochemical characteristics after adding water.
Pilot freeze dryer is common in daily life. Air freeze-drying technology, referred to as freeze-drying, is also known as sublimation air-drying. Freeze-drying is a specific method of pre-freezing water-containing materials and then subliming them in a vacuum state to obtain air-dried objects. Freeze-dried objects have basically unchanged original biological and chemical properties, and are easy to store for a long time. After soaking in water, it can be restored to the form before freeze-drying, and its original biochemical properties can be maintained. Therefore, freeze-drying technology is widely used in various fields such as industrial chemistry and medical equipment.
The design of the freeze-drying machine automatic control system requires simple operation, starting from the material into the button, quick-freezing vacuum sublimation and drying in one go, prompting the shutdown after the freeze-drying is completed. Relevant temperature and pressure control points should be carefully selected and properly controlled. The correlation between quick freezing, vacuum holding and heating should be properly controlled, and the process curve should be set for different materials.