Laboratory Freeze Dryer Lyophilizer with Air-cooled System, 6 kg/24h Water Catching Capacity, and ＜-75℃ Cold Trap Temperature

The principle of freeze-drying, also known as cryodesiccation or vacuum drying, involves the removal of moisture from a substance by controlling temperature and pressure to facilitate sublimation. The process operates through three key stages:

1. Freezing: The material is first frozen to a low temperature, typically below its freezing point, causing water within the material to form solid ice crystals and separate from the substance's solution.
2. Primary Drying: Under frozen conditions, a vacuum is applied to induce direct sublimation of ice crystals into gas phase without transitioning into liquid. This process lowers the boiling point of water and promotes sublimation.
3. Secondary Drying: After primary drying, residual adsorbed or bound water is removed by slightly increasing temperature to facilitate evaporation of these remaining water molecules.

The key objective of freeze-drying is moisture removal through sublimation without transitioning the substance into liquid state. This preserves the structure and activity of materials, prolonging stability and shelf life while minimizing thermal and chemical damage through low-temperature vacuum conditions.

Freeze-drying technology finds extensive applications in food processing, biotechnology, and other industries for drying and preservation purposes. It enables drying of vaccines and food products without heating, thereby avoiding degradation and preserving the activity and quality of heat-sensitive substances.