Vacuum freeze-drying is a better method for dehydration of materials at present. It can freeze the freeze-dried material in advance, and then sublime the water of the material under the condition of low temperature and low pressure to achieve the purpose of dehydration. The sublimated water vapor is collected by condensation. After this vacuum freeze-drying operation, the material becomes a dehydrated material.

The substance after vacuum freeze drying has weak enzymatic effect, the original chemical and physiological properties are basically unchanged, the dried substance has a porous structure, the volume is basically unchanged, and it is easy to recover. It is particularly desirable that the material after vacuum freeze drying can be stored for several years without deterioration.

The condenser is a device used to condense the sublimated water vapor, and its working overflow can reach -45℃~-60℃. The cold source is provided by two 2F6.3 Freon refrigeration units.

The vacuum unit of the dryer is composed of two 2X-5 rotary vane mechanical vacuum pumps and a ZL-8 Roots mechanical booster pump. The vacuum unit is connected with the drying box and the condenser through vacuum pipelines and vacuum valves to form a sealed vacuum system. The vacuum unit is equipped with an electric contact vacuum gauge, which can automatically control the start of the Roots pump according to the pre-selected vacuum level. A vacuum butterfly valve is installed in the vacuum pipeline between the drying box and the condenser, which can be switched on and off at any time according to the requirements of use. The bottom of the condenser is equipped with a branch vacuum pipeline leading to the hot air blower. The middle valve is separated by a 50 butterfly valve. The function of this valve and the branch pipeline is to defrost and dry the condenser. The vacuum branch above the Roots pump is a separate When the mechanical vacuum pump is used, the passage is equipped with a solenoid valve. When the Roots pump is started, the valve is automatically closed. On the vacuum pipeline, there is an electromagnetic belt discharge shut-off valve, which can automatically close the vacuum pipeline when the vacuum pump stops, and put air into the pump at the same time to prevent the vacuum pump oil from rushing into the vacuum pipeline due to negative pressure. Corrugated hoses are installed between the connecting lines of the vacuum pump to prevent vibrations from being transmitted to its components during operation.