Generally, the short path distillation equipment has passed the strict hydrostatic test and trial operation before leaving factory, whose indicators all meet the equipment requirements. The operation procedures of the short path molecular distillation will be introduced as follows.
What should be noticed:
1. The circulating hot oil in the external interlayer is adopted for heating. The temperature is relatively high, so don’t touch.
2. The short path distillation equipment is connected with a vacuum pump. The sealing performance of each component connection should be checked carefully in particular when start the device.
3. The main components of the fine tuning valve construction in a vacuum pump are high density stainless steel needle. The condensation column should be filled with liquid nitrogen before starting up. If the injection volume of the sample is large within one day, it is recommended to connect the first stage receiving port with the three-port rotary valve and use the lifting frame to support the bottom. It is not allowed to stop the device to take the sample and change the flask. It should be started the next day if it is stopped.
4. The sample injector, first stage, second stage and third stage receiving flasks are all glass grinding ports fixed with clips. Hence, don’t overexert yourself in operation.
Preparations before starting the device:
1. Start the cooling water circulating pump, adjust temperature and precondense.
2. The condensation column should be filled with liquid nitrogen, which should be pre-freezed. The liquid nitrogen should be added in time when it is less than the half. Start the oil pump and preheat it after adjusting to the required temperature.
3. Start the rotor of the film scraper for trial operation. Observe whether its rotation is uniform and continuous, and listen to whether there is any noise in the sound of the film scraper. In case of any of the above abnormalities, ask the person in charge of the device or the laboratory teacher to solve the problem.
1. Install the sample injector(tighten it clockwise), the first, second, and third stage receiving flasks, and switch on the cooling water circulation button.
2. Start the rotor of the film scraper, and adjust it to the designated rotating speed(no more than 400r/min).
3. Start the vacuum pump after the liquid nitrogen reaches the required level(no less than the half of the condensation column volume).
4. Adjust the fine tuning valve of the vacuum pump(no lower than 0.5mbar) when the pressure no longer drops.
5. Rotate the sample injector counterclockwise to adjust the injection speed after the pressure is proper.
6. The liquid can be added at any time through the sample injector during the operation.
7. Stop the vacuum pump and adjust back the fine tuning valve when the liquid volume in the injector is about 50ml and no other sample adds. Leave the device in the standby mode when the pressure is 100mbar. After the pressure is relieved, switch off the heater, take off the sample injector, pour out the remaining liquid and change to anhydrous ethanol.
8. Replace the first and second receiving flask with empty ones, turn on the sample injector and slowly inject anhydrous ethanol. Clean the device by utilizing the remaining heat.
9. Shut off the cooling water and the rotor after cleaning. The sample injector and the receiving flask should be taken off and cleaned separately.
10. Turn off the power and clean the work surface.
1. When the flow speed of the sample injector is out of control and there is no obvious improvements by tightening the control valve clockwise, remember not to use excessive force, and only switch off the vacuum pump without other operation. Contact the person in charge of the instrument or professionals to handle it in time.
2. Shut down the rotor and the vacuum pump when the sound of the film scraper is abnormal or the rotating speed is not uniform and continuous. Contact the person in charge of the instrument or professionals to handle it.
The above are introductions to the operation procedures and attentions of the short path molecular distillation. Hoping it can offer some help for people.