The working principle of the pilot freeze dryer is a technique that uses the principle of sublimation to dry. It is to quickly freeze the dried aqueous material into a solid state at a low temperature in advance, and then directly sublimate the frozen water molecules under an appropriate vacuum environment. It becomes a process in which water vapor escapes to remove moisture and preserve substances.
Pilot freeze dryer working principle
In order to ensure the biological activity and quality of the sample, it is necessary to pre-freeze the sample, complete the pre-freezing in the refrigerator or pilot freeze-drying machine, and put it into the shelf of the freeze-drying warehouse to carry out the main drying process of the sample. At this time, the water in the sample was directly sublimated into steam under the action of low temperature and high vacuum in the pilot freeze dryer, and was captured by the low temperature cold trap and vacuum pump. After tens of hours of main drying, most of the moisture in the sample is sublimed away, and the sample is completely retained. The sublimated gas condenses into ice in the cold trap. Due to the pressure relationship, the gas sublimates continuously and then The cold trap condenses into ice, which absorbs heat during sublimation, causing the temperature of the sample itself to decrease and slowing the rate of sublimation. In order to increase the rate of sublimation and shorten the drying time, the product must be properly heated. In order to ensure a higher purity of the sample, the sample can be heated and freeze-dried at this time. It can also be called the post-drying process. The temperature of the sample can reach room temperature, and the entire freeze-drying process is completed.
Advantage
① The substance is always at a low temperature (frozen state) before drying, and the ice crystals are evenly distributed in the substance. The sublimation process will not be concentrated due to dehydration, which avoids the side effects of foaming and oxidation caused by water vapor.
② The dry substance is porous and the volume of the sponge is basically unchanged. There is no shrinkage. It is easily soluble in water and returns to the state before freeze-drying.
③ The principle of ordinary drying is by heating, but these drying methods are carried out at a temperature of 0°C or higher, and the physical and chemical shapes of the dried product vary greatly. During the freeze-drying process, the growth of microorganisms and the action of enzymes cannot be carried out. To a large extent, the original biological and chemical properties of the dried substance are prevented from being denatured, with good stability and easy storage for a long time.
④ The products are dried, desorbed, and plugged in a sterile state in the lyophilization chamber.
⑤ It can remove 95%~99% of water in the substance.
⑥ It is especially suitable for the dry storage of those heat-sensitive substances, such as vaccines, strains, poisons, blood products, etc.
⑦ The major components of the freeze dryer have an optimal structural arrangement, which is conducive to transportation, installation and production operations; it is conducive to cleaning and maintenance, and meets GMP requirements.