Freeze dryer is widely used in medicine, biological products, chemical industry and food industry. Freeze drying technology is very suitable for heat sensitive substances such as antibiotics, vaccines, blood products, enzyme hormones and other biological tissues.
The freeze dryer is composed of refrigeration system, vacuum system, heating system and electrical instrument control system. The main components are drying box, condenser, refrigerating unit, vacuum pump, heating / cooling device, etc. Principle of vacuum freeze-drying: vacuum freeze-drying is to cool and freeze the material containing a large amount of water into a solid in advance, and freeze it to the temperature below the three-phase point of the material. Then using the principle of solid state sublimation, the moisture in the material is sublimed directly from the solid in the form of water vapor under vacuum, and the material itself is left in the frozen ice shelf, so that the dried product does not lose the original solid skeleton structure, maintains the original form of the material, and the product has excellent rehydration. The material is always in low temperature (frozen state) before drying, and ice crystals are evenly distributed in the material. The sublimation process will not be condensed due to dehydration, avoiding the side effects such as froth and oxidation caused by steam. The dry material is porous, and its volume is basically the same. It is easy to dissolve in water and return to its original state. To prevent the physical, chemical and biological denaturation of dry materials to the greatest extent.
Advantages of vacuum freeze drying technology:
(1) Freeze drying is carried out at low temperature, so it is especially suitable for many heat sensitive substances. For example, protein and microorganism will not denature or lose biological activity.
(2) In the process of freeze-drying, the growth of microorganisms and the role of enzymes can not be carried out. So it can keep the original character.
(3) When drying at low temperature, the loss of some volatile components and heat denatured nutrients is very small, which is suitable for drying some chemicals, drugs and food.
(4) Due to the drying in the frozen state, the volume and shape of the products are almost the same, and the original structure is maintained, without concentration. The dried material is porous and spongy. It dissolves quickly and completely after adding water, and almost immediately recovers its original properties.
(5) When drying in vacuum, the materials are in the state of high oxygen deficiency, and the easily oxidized materials are protected.
(6) Drying can remove more than 95-99% of the moisture, so that the dried products can be stored at room temperature for a long time without deterioration.
After using the freeze dryer for a period of time or after using and operating improperly, the vacuum pump oil may be less oil and the emulsified and whitened vacuum pump will continue to smoke. Then, a new vacuum pump oil needs to be filled.
How to change vacuum pump oil in freeze dryer? The following is the operation steps for you to replace the vacuum pump of the freeze dryer:
1. Unscrew the drain hole under the vacuum pump with a screwdriver to drain the remaining waste oil;
2. After the waste oil is drained, tighten the drain hole;
3. Unscrew the filling valve above the vacuum pump and refill the new vacuum pump oil;
4. Observe from the side liquid indicator, fill the vacuum pump oil to two-thirds of the liquid indicator, and then tighten the oil filling valve.
The above is the right way to replace the vacuum pump of the freeze dryer, hoping to help you better use the freeze dryer.