1、 Preparation work
1. Sample pretreatment
Remove most of the solvent in advance through centrifugation or filtration to reduce the burden on the vacuum system.
Materials that are prone to decomposition, oxidation, or phase change should be placed in trays to prevent contamination of equipment.
Liquid solvents and flammable materials with boiling points<150 ℃ are strictly prohibited from being placed inside the box.
2. Equipment inspection
Confirm that the sealing ring of the box door is intact, close the vent valve, and connect the vacuum pump pipeline.
Clean the inner container before heating to avoid residue affecting the drying effect.
2、 Operation process
1. Loading and sealing
Place the materials evenly on the sample rack to ensure smooth airflow inside the box.
Close the box door and tighten the door handle until the sealing ring is fully fitted.
2. Vacuum pumping (pulsating core)
Open the vacuum valve → start the vacuum pump and draw a vacuum expression of -0.1MPa (approximately absolute vacuum).
Pulsation operation: Close the vacuum valve → pause the pump → repeat the vacuum pumping 3-5 times to enhance water desorption.
3. Heating and temperature control
Set temperature (usually ≤ 200 ℃): Use the secondary heating method (such as setting 50 ℃ for the target temperature of 60 ℃, and then adjusting to 60 ℃ after overshoot).
After the temperature stabilizes, enter a constant temperature state (approximately 120 minutes).
4. Inert gas injection (optional)
During the drying process, inert gases such as nitrogen can be introduced to reduce the risk of oxidation.
5. Process monitoring
Regularly observe the vacuum gauge, and if the vacuum level decreases, it needs to be refilled.
Record temperature fluctuations and calibrate the sensor if it exceeds ± 10 ℃.
3、 End process
1. Cooling and breaking vacuum
Turn off the heating power → slowly open the vent valve (to avoid damaging the sample due to sudden changes in air pressure).
After the vacuum gauge is reset to zero, open the box door (if the door is tightly closed, gently pull the sealing ring to introduce air).
2. Material retrieval and cleaning
Wear protective gloves to remove materials.
Clean up the residue inside the box in a timely manner and keep the porous plate unobstructed.
4、 Key precautions
1. Safety protection: Wear insulated gloves and goggles during operation.
2. Vacuum pump protection:
After vacuuming, the vacuum valve must be closed first and then the pump power must be turned off to prevent oil backflow.
Oil pumps are prohibited for water containing samples, and corrosion-resistant water pumps are preferred.
3. Temperature control: The set temperature for thermosensitive materials should be 20 ℃ lower than the boiling point of the solvent (such as 60 ℃ for ethanol).