How to operate freeze dryer
Freeze dryers are widely used. Our best-selling freeze dryers include KD-18ND freeze dryer, KD-10ND freeze dryer and other models. They are widely used for freeze drying of fruits, vegetables, milk, etc.
Vacuum freeze-drying technology, also known as sublimation drying, is a method of pre-freezing water-containing samples and then sublimating the water in a vacuum. Freeze-dried items have basically the same original biological, chemical and physical properties, and are easy to store for a long time. After adding water, they can be restored to the state before freeze-drying and can maintain their original biochemical properties. Therefore, the freeze-drying technology of the freeze-drying machine is widely used in the fields of medicine, food, chemical industry, biological products and so on.
At present, the freeze dryer has been widely used in many fields, especially the use of this technology in food processing to obtain high-quality dehydrated freeze-dried food. So, how to operate the freeze dryer?
how to operate freeze dryer
1. Freeze dryer pre-treatment for freeze drying
Before vacuum freeze-drying with a freeze dryer, the user must first pre-process vegetables, fruits, eggs, milk and other foods, such as red dates, vegetables, and fruits must be washed, sorted, peeled (cored), and sliced. , Liquid concentration and so on. After that, the user should evenly distribute foods such as dates, vegetables, fruits, eggs, milk, etc. in suitable trays to ensure that the evaporation surface of the product should be as large as possible and as thin as possible. The specific parameters can be determined according to factors such as the characteristics of the material and the energy consumption of the freeze dryer.
2. Before freeze-drying by freeze-drying machine
Check whether the freeze dryer is clean, whether the vacuum pump is connected to the refrigerator, turn on the power, and check the air tightness of the exhaust port and the freezing pipe. After that, the user can first put the ready-to-dry products such as red dates, fruits and vegetables, egg and milk foods in a low-temperature refrigerator or liquid nitrogen for pre-freezing, so that the products are frozen and solid. In this process, it is usually necessary to ensure that the product is completely frozen, and the pre-freezing temperature is generally 5°C-10°C lower than the eutectic point of the material shaking, generally below -30°C.
3. Start the freeze-drying machine
First start the refrigeration part, the user should first check whether the high-pressure valve remains open, and then press the "refrigerator" switch to start the operation. Secondly, start the cooling water circulating pump, refrigerator, dry silo solenoid valve and start the circulating pipeline pump. The vacuum system of the freeze dryer, close the solenoid valve of the drying chamber, start the water trap solenoid valve, and close the circulating pipeline pump.
In addition, when the water trap reaches -40°C, the vacuum pump is started. Users should pay attention to the fact that when the vacuum pump starts to work, press the plexiglass cover for a while, which is conducive to sealing. After that, the automatic heating is started, and when all the materials reach the "self-set control temperature value", the shutdown procedure is entered.
Many factors (such as chemical composition, freezing rate, freezing and dehydration stress, glass transition temperature, residual moisture in dry solids, temperature and humidity of the storage environment, etc.) will affect the freeze-drying and storage of food, medicines and organisms. Affect the stability of the active components, and even lead to inactivation. A large number of experimental studies have shown that, except for a few foods, human plasma, milk and other materials that can be directly freeze-dried, most medicines and biological products need to be added with appropriate freeze-drying protective agents and additives to prepare a mixture. Perform effective freeze-drying and storage.
Freeze-drying machine freeze-drying technology is widely used in the scientific research and production of chemical, food, materials, medicine, biological products and other fields. Freeze-dryers such as biological products, biochemical drugs, microorganisms and algae; there are also some vulnerable and easily oxidized substances Drying operations, such as the dehumidification and preservation of biological specimens and biological tissues, historical archives, and cultural relics. The basic composition of the freeze dryer includes a vacuum pump, a cold trap, a freeze-drying chamber, a vacuum and temperature control system, and other functional accessories such as multi-manifolds, capping devices, and ordinary types. Factors to consider when choosing a lyophilizer for laboratory use.
