Axial movement of the pump shaft
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Why does a pump experience shaft drift? What is the impact of improper shaft play on the pump? How should it be adjusted? ?
The axial movement of the pump shaft is mainly caused by unequal pressures on the front and rear cover plates of the impeller; this leads to increased bearing load. The issue can be resolved by adjusting the size of the impeller’s balance holes as well as the diameters of the front and rear cover plates.
What is the effect of thrust bearings on shaft play?
The presence of axial forces causes the shaft to tend to shift; shaft movement can also occur if the balance disk is worn, the gap in the balance drum increases, or the thrust bearings are worn.
Adjustments are made while ensuring the alignment of the flow channels, taking into account factors such as the thermal expansion and contraction of the shaft and the clearance of the balance disk.
The pump experiences a certain amount of cross-flow when it starts up; the cross-flow is minimal when the outlet valve is at its normal opening.
It is caused by the effects of stress
Look at what type of pump it is. The bearing adjustment controls the shaft play of the pump to around 0.1 mm (the gap between the bearing cover and the outer ring of the bearing is 0.02–0.06 mm, plus the play inherent in the bearing itself). A multistage pump uses a balance disk to control shaft movement; when the pump is operating, the balance disk moves back and forth within a balanced position. Adjust the balance disc gap to half of the total string length.
Axial movement of the shaft is caused by the axial force resulting from the difference in area between the suction side and the sealing side of the impeller. Multi-stage pumps generally use balance drums and balance discs to eliminate this axial force, with any remaining axial force being balanced by the bearings. The axial force of a single-stage pump is balanced by the openings in the impeller, with the remaining force being borne by the bearings
Single-stage centrifugal pumps generally should not experience shaft movement; the bearing clearance must be eliminated during installation. Multi-stage pumps require shaft play, which must be adjusted precisely