1、 Preparation before operation
1. Component inspection
Confirm that the rotating motor, distillation flask, receiving flask, condenser tube, vacuum pump and other components are intact, the glass parts are free of cracks, and the interface sealing ring is not aged.
2. Water bath pot filled with water
Inject an appropriate amount of water (or oil bath) into the heating tank to ensure that the liquid level is high enough to submerge the bottom of the distillation flask. Dry burning is strictly prohibited.
3. Connect condensate water
Connect the condensate circulation system, connect the inlet to a water source (such as a faucet), and lead the outlet to the drainage pool to test for smooth water flow.
4. Sample preparation
Pour the evaporated liquid into a distillation flask, with a volume not exceeding 1/2 of the flask's capacity (volatile organic solvents are recommended to be ≤ 1/3), to avoid splashing when boiling.
2、 Instrument connection and setup
1. Install container
Secure the receiving bottle and distillation bottle with a dedicated buckle to ensure a tight interface (vacuum grease can be applied to enhance sealing).
Adjust the lifting handle so that the distillation flask is immersed about 2cm below the liquid level of the water bath, and the liquid level is level with the liquid level inside the flask.
2. Vacuum system connection
The vacuum pump pipeline is connected to the exhaust port at the top of the condenser (non condensing water interface).
Close the ventilation valve (keep the vacuum valve parallel) and check the airtightness of the pipeline.
3. Temperature and speed preset
Turn on the power of the water bath and set the temperature (usually 10-20 ℃ below the boiling point of the solvent).
Start the condensation system cooling in advance (if low-temperature cooling is required, it needs to be started 30 minutes in advance).
3、 Start distillation
1. Vacuum pumping
Turn on the vacuum pump and observe that the pressure gauge pointer is stable below -0.08 MPa (recommended -0.09 MPa). If it does not meet the standard, check the sealing.
2. Start rotation and heating
First, turn on the rotating motor and adjust the speed to 50-300 rpm (low speed for viscous liquids), and wait for stable operation.
Turn on the water bath heating and closely observe the liquid state inside the distillation flask to prevent boiling.
3. Process monitoring
Confirm that the condensate drops evenly into the receiving bottle. If the liquid boils violently:
Suspend heating, raise the distillation flask and detach it from the water bath;
Or slightly open the ventilation valve to reduce the vacuum degree.
4、 End operation
1. Shutdown sequence
Stop rotating → raise the distillation flask → slowly open the vent valve (balance system pressure) → turn off the vacuum pump → turn off the heating → turn off the condensate.
2. Collect samples
After the pressure returns to zero, remove the receiving bottle (if concentrate is required) or distillation bottle (if residual solids are required), and be aware of the risk of burns.
3. Cleaning and maintenance
Empty the water bath and dry it to prevent scaling;
Timely clean glass components to remove solvent residues;
Check the condition of the sealing ring and replace it if necessary.
5、 Key precautions
1. Security protection
Wear goggles and solvent resistant gloves during operation, and keep flammable solvents away from sources of fire in a fume hood.
2. Prevent backflow risk
The shutdown sequence must be strictly followed: first open the atmosphere and then turn off the vacuum pump, otherwise it may cause backflow and damage to the pump body.
3. Regular maintenance
Replace the purified water in the water bath every week and regularly remove scale with citric acid; Check the oil level of the vacuum pump every month.