The freeze dryer equipment originated in the 1920s vacuum freeze-drying technology after 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 that other drying methods cannot match. In addition to its wide application in the fields of medicine, biological products, food, blood products and active substances, its application scale and field Still expanding. To this end, vacuum freeze drying is bound to become an important application technology in the 21st century.
Freeze-drying is a method in which an aqueous substance is first frozen into a solid state, and then the water therein is sublimated from a solid state into a gaseous state to remove water and preserve the substance.
In the process of drying compressed air, the freeze-drying is to precipitate the moisture in the compressed air by lowering the temperature of the compressed air. The freeze dryer (cold dryer) 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.
Freeze dryer equipment advantage
Drying methods are various, such as drying, boiling, drying, spray drying, and vacuum drying, but ordinary drying methods are usually carried out at temperatures above 0 ° C or higher. The products obtained by drying generally have the problems of shrinking size and hardening of the texture. Most of the volatile components are lost, some heat-sensitive substances are denatured and deactivated, and some substances are even oxidized. Therefore, the dried product has a large difference in properties compared with that before drying. The lyophilization method is basically carried out below 0 ° C, that is, in the state where the product is frozen, and only when the residual moisture content of the product is lowered 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 drug remains in the frozen ice shelf, forming a sponge-like porous structure, so the volume after drying is almost constant. Before using it again, as soon as you add water for injection, it will dissolve immediately. Freeze-drying machine Compared with the conventional method, the lyophilization method has the following advantages:
* Many heat sensitive substances do not degenerate or inactivate.
* When drying at low temperatures, some of the volatile components in the material are lost.
* During the lyophilization process, the growth of microorganisms and the action of enzymes cannot be carried out, so that the original traits can be maintained.
* Since it is dried in a frozen state, the volume is almost constant, and the original structure is maintained, and concentration does not occur.
* Since the moisture in the material exists in the form of ice crystals after pre-freezing, the inorganic salt-soluble substances originally dissolved in water are evenly distributed in the material. When sublimating, the dissolved substances dissolved in water are precipitated, which avoids the phenomenon that the inorganic salt carried by the internal moisture migration to the surface in the general drying method is precipitated on the surface to cause surface hardening.
* The dried material is porous and spongy. After adding water, it dissolves quickly and completely, and almost immediately restores its original character.
* Since drying is carried out under vacuum, there is very little oxygen, so some easily oxidizable substances are protected.
* Drying can remove 95%~99% of water, so that the products can be preserved for a long time without deterioration.
* Because the material is in a frozen state, the temperature is very low, so the temperature of the heat source for heating is not high, and 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.
The so-called lack of perfect technology, the main disadvantage of vacuum freeze drying technology is the high cost. Because it requires vacuum and low temperature conditions, the vacuum freeze dryer is equipped with a vacuum system and a low temperature system, so the investment cost and running cost are relatively high.
Freeze dryer equipment main parameters
1: Drying room: size of drying room (width * depth * height), number of shelves, effective total area of shelf, shelf size, shelf temperature
2. Is there a gland function: if it is manual or automatic
3. Condenser: material of the condenser, condenser condensate, final condenser temperature, condensing chamber door material, defroster system
4. Cooling system: compressor used
5. Drying ability: dry sample weight every day
6. Power supply:
7. Monitoring method: use external computer or machine's own liquid crystal display, and monitor the parameter design
Freeze dryer equipment application
Vacuum freeze-drying technology has a wide range of applications in the fields of bioengineering, pharmaceutical industry, food industry, materials science and deep processing of agricultural and sideline products.
Freeze drying of drugs includes two parts: western medicine and traditional Chinese medicine. Western medicine freeze-drying has been developed in China, and many larger pharmaceutical plants have freeze-drying equipment. In terms of injection, the freeze-drying process is used more, which improves the quality and shelf life of the drug, and brings benefits to both doctors and patients. There are not many varieties of freeze-dried medicines, the prices of products are high, and the drying process is not advanced. In traditional Chinese medicine, it is limited to the lyophilization of a small amount of Chinese medicinal materials such as ginseng, velvet, yam, and Cordyceps sinensis. A large number of proprietary Chinese medicines have not been freeze-dried, which is far from the foreign countries. A few years ago, Japan launched the "Western Chinese Medicine" system, which changed the method of tanning of traditional Chinese medicine, solved the tradition that Chinese medicine could not be made into injection or tablet, and solved the problem of Chinese medicine not treating acute illness. Therefore, the Chinese traditional medicine freeze-drying process And product research has great potential to dig.
In the field of biotechnology products, freeze-drying technology is mainly used for the production of drugs such as serum, plasma, vaccines, enzymes, antibiotics, hormones; biochemical inspection drugs, immunology and bacteriology; drugs; blood, bacteria, arteries, bones Long-term preservation of skin, cornea, nerve tissue and various organs.
Current status and development of freeze dryer equipment
The application and equipment of freeze-drying technology are inseparable. So far, the form of freeze-drying equipment is mainly divided into two types: intermittent and continuous. The scale of equipment ranges from less than one square meter to several tens of square meters. .
Intermittent freeze-drying equipment
Intermittent freeze-drying equipment is suitable for multi-variety and small-volume production, especially in the food field for seasonal food production. With stand-alone operation, if one device fails, it will not affect the normal operation of other devices. Intermittent freeze-drying equipment is convenient for controlling the heating temperature and vacuum requirements of different stages of material drying. The manufacturing, maintenance and repair of the equipment is easy. However, since the operations such as loading, unloading, and starting take more time, the equipment utilization rate is low and the production efficiency is not high.
Continuous lyophilization equipment
Started exploring and using continuous vacuum freeze drying equipment at home and abroad. The continuous equipment is characterized by the production of a single product with a large output and sufficient raw materials, especially for the production of pulp and granular products. Continuous equipment is easy to implement automatic control, simplifying manual operation and management, and its main disadvantage is high cost.
With the end of GMP certification, the domestically produced excellent freeze-drying equipment for medical use has entered the modernization stage, with complete functions, reliable work and stable performance. It can realize online cleaning (CIP) or steam sterilization (SIP), various technical indicators. Can meet the needs of lyophilized production of biological products and pharmaceuticals. In contrast, the specifications of foreign freeze-drying equipment are more than domestic, with complete equipment, energy-saving structure, and continuous freeze-drying equipment. In order to ensure the quality and energy saving of freeze-dried products, combined freeze-drying equipment, such as spray freeze-drying equipment, is often used in combination with freeze-drying equipment and other drying equipment.
In the future, how to improve the freeze-drying efficiency, shorten the drying time and save energy will ensure the goal of the majority of freeze-drying industry workers under the premise of ensuring product quality.