Impeller Eye Shift - Vibration Trouble
Impeller Eye Shift - Vibration Trouble
(OP)
Ladies and Gents,
We are investigating the cause of vibration during the operation of a cantilever pump. It should be noted that the pump has vibrated ever since the impeller was changed some months ago.
We have found that the center of the impeller eye is NOT the center of the impeller vanes. We have measured the varience and have determined that the center of the impeller (the white dot in the photograph) is 0.25" off from the center of the impeller vanes. My question is whether or not this would contribute dramatically to a hydraulic imbalance or if this varience should be no problem at all. The impeller is 13.87" in diameter. The rotational speed is 1200RPM. The cantilever shaft is ~4 ft. long from the lower bearing.
Please note that the dimensions given in the attached picture are 3" from the center of the vanes. The white dot is the actual center of the impeller and also coincides with the position of the shaft (it is centered on the back of the impeller). Again, the varience is 0.25" from impeller center to vane tip center.
Our belief is that the impeller vanes are unevenly loaded causing the measured vibration. I look forward to your thoughts.
Thanks in advance.
Adam
We are investigating the cause of vibration during the operation of a cantilever pump. It should be noted that the pump has vibrated ever since the impeller was changed some months ago.
We have found that the center of the impeller eye is NOT the center of the impeller vanes. We have measured the varience and have determined that the center of the impeller (the white dot in the photograph) is 0.25" off from the center of the impeller vanes. My question is whether or not this would contribute dramatically to a hydraulic imbalance or if this varience should be no problem at all. The impeller is 13.87" in diameter. The rotational speed is 1200RPM. The cantilever shaft is ~4 ft. long from the lower bearing.
Please note that the dimensions given in the attached picture are 3" from the center of the vanes. The white dot is the actual center of the impeller and also coincides with the position of the shaft (it is centered on the back of the impeller). Again, the varience is 0.25" from impeller center to vane tip center.
Our belief is that the impeller vanes are unevenly loaded causing the measured vibration. I look forward to your thoughts.
Thanks in advance.
Adam





RE: Impeller Eye Shift - Vibration Trouble
Adam
RE: Impeller Eye Shift - Vibration Trouble
Adam
RE: Impeller Eye Shift - Vibration Trouble
RE: Impeller Eye Shift - Vibration Trouble
Walt
RE: Impeller Eye Shift - Vibration Trouble
After any works on impellers dynamic balancing is a must to avoid problems subsequently since we have most affected/ sensitive member of the system at risk; in a way!
Best Regards
Qalander(Chem)
RE: Impeller Eye Shift - Vibration Trouble
Thanks all.
Adam
RE: Impeller Eye Shift - Vibration Trouble
If the above is correct and true.
May I suggest to check its balance in a pan like manner with respect to It's Center of gravity and recheck through dynamic balancing then repeat till fully balance either way?
This is just out of blue,I suggest;for possible trouble shoot indeed.
Best of luck
Best Regards
Qalander(Chem)
RE: Impeller Eye Shift - Vibration Trouble
Adam
RE: Impeller Eye Shift - Vibration Trouble
Impeller removed from shaft and Very very Critically statically balanced for its center of gravity in a Nice horizontal flat condition,therafter rechecked for dynamic balancing and few times rechecking/repeating the process.
Slight trial and error to resolve the issue I mean.
Best Regards
Qalander(Chem)