Vacuum freeze-drying is a better method of material dehydration at present. It can freeze the freeze-dried material in advance, and then sublimate the moisture of the material at low temperature and low pressure to achieve the purpose of dehydration. Sublimated water vapor is collected by condensation. After this vacuum freeze-drying, the substance becomes dehydrated.
After vacuum freeze-drying, the enzymatic activity of the material is weak, the original chemical and physiological properties are basically unchanged, the drying material is porous structure, the volume is basically unchanged and easy to recover. In particular, the vacuum freeze-dried substances can be preserved for several years without deterioration.
Condenser is a device for condensing and sublimating water vapor. Its working overflow can reach - 45 C to - 60 C. The refrigeration source is provided by two 2F6.3 Freon refrigeration units.
The vacuum unit of dryer is composed of two 2X-5 rotary vane mechanical vacuum pumps and one ZL-8 Roots mechanical booster pump. The vacuum unit is connected with the drying box and condenser through vacuum pipelines and vacuum valves, forming a sealed vacuum system. The vacuum unit is equipped with an electric contact vacuum meter, which can automatically control the starting of Roots pump according to the pre-selected vacuum position. There is a vacuum butterfly valve in the vacuum pipeline between the drying box and the condenser, which can be switched on and off at any time according to the use requirements. The bottom of the condenser is equipped with branch vacuum pipeline leading to the hot air blower, and the middle valve is separated by 50 butterfly valves. The function of this valve and branch pipeline is for defrosting and drying of the condenser. The vacuum branch pipe above the Roots pump is the passageway when the mechanical vacuum pump is used alone. It is equipped with solenoid valves. When the Roots pump is started, the width will automatically close. Close. The vacuum pipeline is equipped with a solenoid belt bleeding stop valve. When the vacuum pump stops, the vacuum pipeline can be automatically closed. At the same time, air is put into the vacuum pipeline to avoid the vacuum pump oil rushing into the vacuum pipeline due to negative pressure. A corrugated hose is installed between the connecting pipes of the vacuum pump to prevent vibration from passing to its components during operation.
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