How does shaft seizure occur in centrifugal pumps (not due to bearings)
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How does shaft seizure occur in centrifugal pumps (not due to bearing issues)? In our workshop, two centrifugal pumps often experience shaft seizure; the reason is that the material (a suspension) undergoes sudden aggregation at the impeller, which causes the impeller to get stuck. Each time, it is necessary to disassemble the pump and clean the impeller, and this can also cause damage to the mechanical seal. It is also not conducive to the stability of production. But the cause was never found. There are a total of 8 centrifugal pumps of the same type, but this situation rarely occurs with the other 6. I would appreciate some guidance from an expert.
Carefully examine the comparative analysis of the design and operating parameters of these two pumps versus those of the other six pumps, to identify the causes of the problems.
Are the models and operating conditions of the 8 centrifugal pumps exactly the same? If they are exactly the same, the problem could be related to the imported filter, or it might be that the clearance between the port rings of the two pumps in question is smaller than that of the other pumps (this possibility is low).
The 6 units are the same; they operate under the same conditions, and all of them are equipped with filters
There must be particles inside; of course that will damage the bearings
It is necessary to check whether the fit dimensions of the bearing with the shaft and the bearing housing meet the requirements, as well as the lubrication condition.
Check if there is any blockage in the outlet pipeline. Try moving these two pumps to other normal locations.
First, it should be clarified that what you’re referring to is not called “shaft binding.” In the context of pump maintenance, “shaft binding” is a specific term that denotes a situation in which the shaft of a pump or other centrifugal equipment fuses with its bearings due to lubrication issues or other reasons, resulting in an inability to rotate. What you’re referring to is likely the impeller being stuck. Check the clearance of the ring seal – see if the clearance is not appropriate, or if the material of the ring seal isn’t suitable for the temperature of your material. Additionally, when cleaning the impeller, there’s generally no need to touch the sealing elements; however, repeated disassembly will definitely have an impact on the seals. Focus on checking the ring seal first.
1. Check if it’s a filter issue
I think it’s mainly a problem with the pump! It’s best to give the pump a thorough inspection.
The main reasons for bearing seizure are as follows: 1. Improper bearing assembly, with too small an axial clearance or excessive radial force. 2. Poor lubrication. 3. There are issues with installation alignment. 4. The temperature of the fluid pumped is high, and the cooling measures are inadequate. 5. There is a problem with the quality of the bearings. Preventive measures: 1. Check the lubrication level to ensure it is at an appropriate level – it should neither be too low nor too high, as either condition can prevent heat from being dissipated. 2. Ensure reasonable axial and radial installation clearances to provide adequate expansion clearance during pump operation. 3. Ensure precise alignment to prevent the bearings from being subjected to unnecessary forces. 4. Avoid overloading the pump, which increases the load on the bearings. 5. Avoid pump cavitation, as vibration will exacerbate bearing wear. 6. Operate the pump correctly when starting and stopping it; incorrect operations can cause damage to the pump.