Freeze-drying technology, as a drying technology, freezes water-bearing substances into a solid state and then sublimate the water from solid state to gaseous state to remove water and preserve the substance.
During drying compressed air, freeze drying is carried out by lowering the temperature of the compressed air to precipitate moisture in the compressed air. The freeze dryer (cooler) works like a refrigerator. After the compressed air passes through the frozen compressed air line, the temperature of the compressed air drops to the required temperature to meet the drying requirements.
The Lyophilization originated in the 1920s vacuum freeze-drying technology after several decades of ups and downs and made great progress in the last 20 years. In the 21st century, vacuum freeze-drying technology has become more and more popular with people due to the advantages unmatched by other drying methods. In addition to its wide application in the fields of medicine, biological products, food, blood products, and active substances, its application scale and field is expanding. Therefore, vacuum freeze drying of freeze dry machine will be an important application technology in the 21st century.
Vacuum freeze-drying method has the following advantages:
First, The dried material is porous and spongy. After adding water, it dissolves quickly and completely, and almost immediately restores its original character.
Second, Since drying of freeze dry machine is carried out under vacuum, there is very little oxygen, so some easily oxidizable substances are protected.
Third, Drying can remove 95%~99% of water so that the products can be preserved for a long time without deterioration.
Last, because the material keeps in a frozen state, with low temperature, so the heater with normal temperature or low temperature can meet the requirements. If the freezing chamber and the drying chamber are separated, the drying chamber does not need to be insulated, and there is not much heat loss, so the utilization of heat energy is economical.
However, vacuum freeze-drying technology is expensive. Because it requires a vacuum and low-temperature conditions, the vacuum Freeze Dry Machine is equipped with a vacuum system and a low-temperature system, so the investment cost and running cost are relatively high.