The freeze dryer uses the method of freeze-drying to preserve the substance, the principle is to freeze the aqueous substance into a solid state first, and then directly sublimate the solid water in the substance into gaseous water, so as to achieve the purpose of removing the water in the substance.
The freeze dryer is mainly composed of refrigeration system, heating system, vacuum system, circulation system, hydraulic system, control system, CIP SIP system and box. The main components are drying oven, condenser, refrigeration unit, vacuum pump, heating and cooling device, etc.
Manual operation one.
1. Pre-freezing of products (pre-cooling of the front box).
Operation method: open the circulating pump and compressor, and open the plate cold valve after 30 seconds. Freeze the product to the temperature required by the process (generally about -35 -45).
2. The insulation stage of the product after pre-freezing I
Operation: Do not do anything, keep the state of phase 1, under special circumstances (some products can not be frozen to too low temperature), so it is necessary to turn off 1 2 compressors. After the products have reached the required temperature of the process (generally all 3 probes are required), the temperature will be kept for a period of time (generally 2-4 hours, determined by the process requirements).
3 Close the plate cooling valve, open the condenser valve, and reduce the condenser temperature to below -45. Condenser pre-cooling (rear box pre-cooling).
4 Pre-vacuuming
Turn on the vacuum pump, the butterfly valve, after 1 2 minutes, open the diaphragm valve, and after 10 to 15 minutes, open the roots pump.
5. The insulation stage after the product is pre-frozen
In the pre-cooling and pre-vacuum stages of the condenser, the temperature of the product may rise, and it is necessary to refrigerate the product according to the process requirements.
Operation method: After setting the temperature of the heat transfer oil to the desired temperature of the cold mixing in the manual parameters of lyophilization, the electric heating is turned on. The doping valve will automatically open to cool the heat transfer oil.
6 Begin to sublimate
Operation: Heating and heat preservation are carried out in stages according to the process requirements. Specific method: After setting the temperature of the heat transfer oil in the manual parameters of lyophilization, set the required time and turn on the electric heating treatment. After the temperature of the heat transfer oil reaches the set value, and the holding time also reaches the required time of the process, the next step is to heat up and heat preservation, and so on until the sublimation is completed. When the vacuum level of the front box is reduced to below the range required by the process (generally between 10 and 30pa), the product is heated and heated.
7. Product insulation stage
When the temperature of the product reaches the highest temperature required by the process, the constant temperature is 2-4 hours (determined by the process requirements).
8 Aeration stage
Operation method: In the leakage parameter setting in the freeze-drying manual parameter setting, set the parameters required by the process for aeration, and open the leakage. Due to the low moisture content in the later products, the vacuum in the box is too high, resulting in the sublimation rate slowing down, and the sublimation rate can be appropriately blended to speed up the sublimation rate.
9 Determine whether the lyophilization is over
When the 7th stage is over (generally requires 3 probes to arrive), generally speaking, it can be judged that the moisture in the product has basically been sublimated (generally requires that the moisture content of freeze-dried products should be less than 5%-3%), and there is also a way to determine that the partition valve is closed, observe the change of the vacuum degree of the front box, if the rising rate is similar to the leakage rate of the freeze-drying box, it can also be judged that the freeze-drying is over.
Automatic operation II.
Automatic operation is generally set according to the experience of manual operation after the freeze-drying process is relatively mature, and the operator is required to have a certain understanding of lyophilization before setting.
Notes:1Check the inner chamber of the instrument before use, dry (no liquid water is present).
2.Samples should be frozen well and should not have liquid water.
3.After the sample is removed, the tray should be cleaned and dried with a towel.
4.Before turning on the vacuum pump, pay attention to check the oil level and color of the vacuum pump oil, and the replacement of the vacuum pump oil is about 500 hours.