First, before drying, firstly treat the sample material […]
First, before drying, firstly treat the sample material to make the sample shape and size uniform, loosely spread on the metal plate, or placed in glassware and other containers to make the thickness uniform, generally less than 2cm.
Second, the sample containers should be placed on the metal plate. Do not stack the containers with each other. There should be no space between the container and the metal plate.
Third, due to the different nature of the various sample materials, the minimum temperature required and the time of maintenance are different. Generally, the water content is high, the nutrient is rich, and the object with special odor requires rapid freezing to keep its nutrients. It is destroyed and retains its original smell.
Fourth, when freezing the sample material, it is generally required to freeze the sample to the minimum temperature and keep it for 1-2 hours before vacuuming for drying. If it is not frozen, the sample will rupture under the action of the vacuum. If the sample is a liquid substance, it will erupt, causing the freeze-drying to fail.
Fifth. when lyophilizing, the temperature of the condensation chamber of the Freeze Dry Machine should be kept below -40 °C, and the vacuum pump should be able to maintain a certain degree of vacuum. The general pressure is between 0.1 and 0.3 mbar.
Finally, when the sample material is dry, the temperature of the sample chamber of the Freeze Dry Machine should be raised to (lower) to room temperature. First, close the valve between the vacuum pump and the sample chamber, the condensation chamber, then turn off the vacuum pump, and slowly open the vent valve. Open all the way to avoid the dry sample being blown away.