Reason for Rotary Evaporator Vacuum Degree Not Dropping

Rotary evaporators are commonly used equipment in laboratories and are widely applied in chemistry, chemical engineering, biomedicine and other fields. Vacuum is the most important process parameter of the rotary evaporator.
 
Rotary evaporator is a kind of experimental equipment that can carry out negative pressure and atmospheric pressure distillation, and the whole machine has good sealing performance. But sometimes there are situations where the vacuum cannot be pumped up. Today some of the reasons why the vacuum cannot be lowered will briefly summarized here.
 
1. There is some solvent in the container, and because of the limitation of saturated vapor pressure, the vacuum cannot be lowered. At this time, the container needs to be cleaned, and then try to start it again.
2. The circulating water vacuum pump fails or the water temperature is too high, causing the vacuum to fail to drop. Replace the circulating water of the vacuum pump first. If the problem is not solved, the circulating water vacuum pump needs to be cleaned and checked.
3. The vacuum cannot be reduced due to the loose pipe connecting the vacuum pump and the rotary evaporator or the loose joint. In this case, the only thing needs to be done is to tighten the connection and joint.
4. If the radiotherapy valve or pressure control valve is blocked by foreign objects or the glass wool sandwich panel is damaged, the vacuum cannot be lowered. If the sealing degree of the rotary evaporator has leaked, it can also cause the vacuum to not drop.
5. There is also a situation that the efficiency of the condenser is not enough, which causes a large amount of gaseous materials to accumulate in the container, and the vacuum cannot continue to drop. If the gas is too volatile, it will also affect the vacuum of the rotary evaporator.
6. If the sealing ring is not replaced for a long time, it may be corroded, which will reduce the overall sealing performance of the equipment. Therefore, the sealing ring needs to be inspected and maintained regularly.