Vibration problems in centrifugal pumps
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The plant has a centrifugal pump that meets API610 standards, model 40-400, with a flow rate of 24 m3/h and a head of 150 m. Vibration levels during water transport tests were above the acceptable range (the vibration measurement device indicated 70 mm), but no issues were detected regarding vibration after the pump was returned to the factory for further testing. Now, after pulling it back and reinstalling the vibration sensor, the level is still above the limit; the inlet has a diameter reduction from 100 to 80, while the outlet has a diameter reduction from 40 to 80. Please help analyze the reasons!
Vibration is excessive when the coaxiality exceeds 10 microns
Putting the assembly issues aside, isn’t the outlet diameter a bit too large?
First, check whether there is vibration when the motor runs idle; second, check the flow rate issue – there may be a problem with the outlet diameter, resulting in an excessively high flow velocity.
Is the foundation solid? Are there any diameter changes at the outlets, and are there many elbows?
I agree with the view from the fifth floor: the maximum for imports is 100, and the minimum for exports is 40. This diameter reduction is not just a bit large – it’s actually quite large
Expansion joints are present at the inlet and outlet, causing resonance
You can contact the manufacturer and ask them about the size of the pipes used for water transport tests. Personally, I think it might be due to improper piping design; the high flow rate causes excessive vibration. Adjust the opening degree of the outlet control valve and observe any changes in vibration. The opening degree should not be too small, as too small an opening can also lead to high outlet pressure, which in turn can cause cavitation and vibration. Another question: is the medium for this pump also water? What’s the temperature? I hope the original poster can also share that. If the problem is resolved, please let me know the reason and the solution; I hope to learn from it.
Problems such as installation leveling and alignment, pipeline layout, and fluid cavitation are all possible. It would be best for the poster to upload a photo for easier analysis.