Vacuum freeze dryer, referred to as freeze dryer, uses the principle of sublimation to make the moisture in the pre-frozen material directly sublimated into water vapor in the ice state without the melting of the ice, so as to achieve the purpose of drying. It is suitable for the drying of some biochemical samples, medicines and foods.
Tips for vacuum freeze dryer operation
1. Before drying, firstly process the sample material to make the shape and size of the sample consistent, and lay it loosely on the metal plate to make the thickness consistent, generally not more than 2cm.
2. Due to the different properties of various samples, the required minimum temperature and holding time are also different. Generally, objects with high water content, rich nutrients and special odor require rapid freezing to keep their nutrients from being destroyed and to maintain their original odor.
3. When freezing the sample material, it is generally required that the sample is frozen to the set minimum temperature and kept for 1 to 2 hours before vacuuming and drying. If it is not frozen, the sample will rupture under the vacuum. If the sample is a liquid substance, it will erupt and cause the failure in freeze-drying.
4. When the drying of sample material is completed, the temperature of sample chamber should rise to room temperature. First, close the valve between vacuum pump and sample chamber and condensation chamber, then turn off vacuum pump, and slowly open vent valve. Do not open it all at once to avoid blowing the sample away.
5. Before each startup of laboratory freeze dryer, check whether the refrigeration system is normal and whether the oil level of vacuum pump is between the two red lines.
6. After drying of the sample material, please turn off the main power, slowly and completely open air valve, and at the same time release the water in the cold well after defrosting.
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