Seeking help with centrifugal pump evacuation
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Dear technical experts, I would like to ask for your advice: one of the centrifugal pumps in our unit’s negative pressure tower often runs out of fluid; it takes a long time to refill the pump, and once it stops operating, it will definitely need to be refilled again next time! The inlet pipeline of the centrifugal pump is very long and has many elbows; I think it’s caused by the excessive length of the inlet pipeline – I’m not sure if that’s indeed the reason!
What kind of material is the poster trying to transfer? The centrifugal pump does not have very strong self-priming capability, and the inlet pipeline is too long with many bends; there is negative pressure inside the tower, which prevents the centrifugal pump from drawing in the material, resulting in vacuum conditions that damage the mechanical seal
It’s possible that the length of the pipeline does have an impact.
Just find a check valve and install it; it should be available. Check to see if there’s any internal leakage ? ?
1. It’s probably caused by high hydraulic losses; your guess is likely correct.
It is caused by the pipeline being too long and too thin. Solutions: 1. Ensure stable level control； 2. Minimum pump backflow opening.
Try connecting the pump outlet to the tower.
What is being transported are heavy aromatics, and the bottom temperature of the tower is around 230°C! Thank you for your reply!
Thank you all. If the inlet pipeline is too long, according to Bernoulli’s equation, it’s likely that the suction head at the inlet is too low, which results in insufficient flow at the outlet and an easy risk of vacuum formation. I’m not sure if my understanding is correct!
Yes, the most reasonable solution is to move the pump closer to the bottom of the tower; the closer, the better. Either increasing the inlet head pressure or enlarging the inlet pipe diameter will work.
The centrifugal pump has weak suction power, and feeding is relatively slow. You can try adding a foot valve, or switch to a positive displacement pump