What to do about vibration during the operation of a multi-stage centrifugal pump?
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The balance disc is also free of wear, and the bearing is N308
This post was last edited by CHANGBAISHI on 2020-1-18 at 16:18. For problems that occur with such pumps during normal operation, one can only check whether the coupling and related components are damaged, or examine the bearings at both ends; if the problem persists, the pump will need to be disassembled for inspection, which is a time-consuming process. After disassembly, it is also necessary to check whether the spindle is bent or to perform dynamic balancing. For reference.
Inspect the coupling and the clearance of the support bearings; after the impeller is assembled, perform dynamic balancing on the entire shaft. Check the coaxiality of the bearing rings with the inner circle of the pump casing. The amount of work involved is significant, and many multi-stage pumps experience excessive vibration or a decrease in head after maintenance. The causes can be identified through the points mentioned above – give it a try!
If the vibration is too severe, it needs to be thoroughly disassembled for dynamic balancing. If it’s detected early, balance adjustment can be carried out; if detected late, the mouth rings on various parts could end up in trouble.
The balance device shows no wear, indicating that the axial force is well balanced. Then look for the reasons in production, structure, and operation. 1. What is the imbalance amount of the entire rotor? What is the static deflection of the shaft? 2. What is the diameter-to-length ratio of the shaft? Is the stiffness of the bracket sufficient? 3. Are the vibrations at the front and back consistent? Do they originate from the piping, or from the motor or coupling? 4. Measure the spectrum (they are available on Taobao at a fairly low price) to identify the source of vibration.
In the previous post, you said that dynamic balancing hadn’t been done yet – how much the shaft is bent also causes vibration
Did the vibration occur suddenly? Is it operating at the optimal operating point? Is the concentricity between the bearing housing and the pump body satisfactory? Axis bending? Clearance between the bearing and the bearing housing? Rotor dynamic balancing?
Boiler feed water pump: check alignment and leveling. Dynamic balance check. Is the process fluctuating?