Seek an answer
Thread Content
A multi-stage centrifugal pump is under maintenance. After the rotor was assembled, the vibration level was within acceptable limits when the shaft sleeve cover was not tightened with force; however, it exceeded the specified limits once the cover was tightened with force (it was checked that the bending of the main shaft was within acceptable limits). What could be the cause of this? How to handle it? Answer: This is mainly caused by the impeller and sleeve end faces not being perpendicular to the axis. Solution: The end faces of the impeller and the bushing need to be manually scraped and polished so that they can make good contact. Red lead powder can be used to polish the end faces of both the bushing and the impeller, removing any high spots so that the contact area reaches over 80%; this will resolve the issue.
Check the form and position tolerances; in most cases, it is a violation of parallelism or perpendicularity.
It’s slipping; using some copper sheet with a coating should help alleviate the problem. The main issue is wear on the shaft, so it’s necessary to repair that shaft at an appropriate time
Is there anything inside between the shaft sleeve and the impeller, and are there any high points?
It’s the radial runout value, right? What type of pump: diaphragm pump, partition pump, etc.? Is it a rolling bearing or a sliding bearing? How is the centering of the pump shaft?