Axial movement of centrifugal pump shaft
Thread Content
What are the causes and ways of regulation? Is it the thrust bearing or the radial bearing that limits the amount of shaft play?
Radial positioning bearings serve to limit shaft play; the generation of axial thrust also leads to shaft play. Thrust bearings are capable of overcoming the axial thrust that occurs during pump operation
Sending a picture of the pump; hello everyone, I’m here to help solve your problem
The thrust bearings are used to control the shaft runout. If this problem occurs after some time of use, it is likely that the thrust bearings have worn out severely. If they are new bearings, then the shaft runout needs to be adjusted by adding shims as appropriate. In the case of thrust bearings, the radial bearings do not bear any thrust forces; whereas in the absence of thrust bearings, usually two deep groove ball bearings are used, which then bear certain axial forces
Radial bearings are subjected only to radial forces, while thrust bearings are subjected to both axial and radial forces. When a centrifugal pump starts, it attempts to move forward toward the outlet for an instant; at this time, the thrust bearing resists this movement by exerting force. Uneven water inflow on both sides of the double-suction impeller during operation, or wear of the balance disk in multi-stage pumps, can both increase shaft play. The amount of play is mainly adjusted by the thickness of the adjustment shims in front of the bearing.
Is it possible that the shaft has shifted, causing the suspension assembly to move outward? It’s not necessarily a problem with the bearings
In a vertical centrifugal pump, the thrust bearings are installed face to face, with a spacer ring in between. The allowable shaft play is 0.1–0.2 mm; the actual measured shaft play is 0.09 mm. The experienced technicians said that it’s necessary to reprocess the intermediate spacer ring and increase its height, which will allow for more shaft play
Was it said upstairs that radial positioning bearings serve to limit shaft play? Is that correct? What is the proper way to measure shaft play, and how can the thickness of the shims be adjusted?
Regarding the shaft play in multi-stage centrifugal pumps, information on this can be found on Baidu. During operation, the shaft play corresponds to the gap in the balance disc; if this play is too large, the mechanical seal will leak, and in severe cases the bearings will be damaged. The thickness of the adjustment shim is something that is machined when adjusting the clearance of the balance disc; depending on different maintenance experiences, the amount of the shim used can be increased or decreased as needed!
The main cause of shaft play in vertical pumps is wear of the thrust bearings. It is the result of the long-term effect of gravity and the axial force of the centrifugal pump. Face-to-face adjustment can be carried out by adding thin shims between the inner rings of the thrust bearings.