Freeze vacuum dryer instructions

Fundamental

Under the high pressure freezing vacuum state, the sublimation principle is used to remove the water in the pre-frozen material from the ice state to the water vapor, thereby drying the material.
Vacuum freeze dryers are widely used in a variety of products to ensure that the protein, vitamins and other nutrients in the product, especially those volatile heat-sensitive components, are not lost, thus maximizing the original nutrients. It can also effectively prevent oxidation during the drying process and avoid the conversion of nutrients and state changes. The lyophilized product has a sponge shape, no shrinkage, good rehydration, and little water content. After storage, it can be stored and transported at room temperature for a long time.

Steps

1. The system is ready to check whether the system is clean and dry, whether the vacuum pump is connected to the freezer, turn on the power supply, and check the tightness of the exhaust port and the freezing tube.
2. The sample should be pre-cooled to at least -40 ° C and can be carried out in a deep freezer (-70 ° C) or liquid nitrogen (-196 ° C). Open the sealed tube switch, remove the freezer compartment, and place the sample on the partition in the freezer compartment. Close the sealed tube switch.
3. Open the freezer switch and wait for 20 to 30 minutes until the temperature of the freezer compartment is below -40 °C.
4. Vacuum the vacuum pump switch and wait 10 to 15 minutes until the system pressure is below 100 millitorr.
5. The monitoring process ensures that the system parameters (freezing temperature, vacuum pressure) are within the normal range;
Regularly check the icing in the freezer to determine whether to defrosting;
Observe whether the sample is completely dry. Generally, the drying process takes 24 to 72 hours, depending on the specific sample.
6. Turn off the system to turn off the main switch, connect the exhaust pipe or open the sealed pipe switch to release the vacuum.
Turn off the vacuum switch, turn off the freeze switch, and take out the sample.
7. System maintenance defrost: If there is frost in the compression chamber below the freezer compartment, connect the drain pipe and then use a small amount of hot water (not more than half the volume of the compression chamber) to promote the melting of the frost. It is not possible to defrosting by tapping on ice.
Dehumidification: The water mist on the surface of the compression chamber, freezer compartment, vacuum pump compressor and gasket should be dried.
Cleaning: The compression and freezing compartments can be cleaned with a mild detergent or soda, then dried and removed, and the drain hole resealed.
Pump oil: Check the oil level regularly to eliminate oil mist.

Precautions

1. The sample should be kept frozen and cannot be “refused”.
Most solvents have a freezing point above -40 ° C, so a freezer compartment temperature below -40 ° C keeps the average sample ice.
To ensure that the sample does not “return”, the frozen sample can be made into small pieces of less than 20 mm.
2. Toxic or corrosive samples.
It is best not to use freeze-drying. If it is necessary, it requires more system maintenance and requires the purchase of a specific filter to protect the vacuum pump.
3. Vacuum pump oil should be kept clean.
The yellowish or colorless oil is clean, the darker color indicates acid contamination, and the hazy turbidity indicates water contamination. Need to change the oil when there is pollution.