Working principle: Freeze drying is a technology that u […]
Working principle: Freeze drying is a technology that uses the principle of sublimation to dry. It is a process of rapidly freezing the material to be dried at low temperature, and then in a suitable vacuum environment, the frozen water molecules are directly sublimated into a process of water vapor overflow. .
Composition of the original: mainly including cold hydrazine, vacuum pump, drying box and motor and other originals.
(1) Check the oil level gauge of the vacuum pump. Turn on the power, turn on the main switch, turn on the refrigerator, and lower the temperature. Depending on the temperature of the different refrigerators, the low temperature is generally different. Normally, the temperature is lowered for 30-40 minutes, and the general temperature is lowered below -50 ° C;
(2) Take out the pre-frozen material and put it on a drying rack. Generally, it should not be too much. One container contains less than 1/2 of the amount, and the sample is thin and freeze-dried for a short time. (For example, my sample is Schisandra chinensis extract, frozen in -80 ℃ in advance, and then put it into the freeze dryer, be sure not to put too much sample, and then spray out when lyophilized)
(3) Check to make sure that the seal ring is free of debris, then put the vacuum cover on and tightly fit the seal ring. If the seal is not tight, you can add a small amount of water to the interface, and the seal must be tight, otherwise the vacuum cannot be drawn.
(4) Confirm and close the drain and bleed valve (one valve);
(5) Turn on the vacuum gauge and vacuum pump of Freeze Dry Machine, observe the pressure indication in the display, and confirm the vacuum state of the vacuum cover. The general pressure is reduced below 20kpa;
(6) After drying, first open the drain inlet valve, then close the vacuum pump and vacuum gauge, wait for the air pressure to return to normal, and take out the sample.
(7) After the cold hydrazine ice has melted, wipe the cold hydrazine with clean paper.
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