Abstract: In this paper, the axial force problems of 2 vertical multistage pumps used in a chemical plant in China are analyzed and calculated, and modification measures are put forward including replacing the material of guide bearing and changing the size of the seal ring of impeller. The axial force is greatly reduced, and the vibration, shaft seizing and mechanical seal leakage problems caused by the axial force are solved. Temperature and vibration monitoring instruments are also added. In addition, the principle and characteristics of axial force balancing measures commonly used for centrifugal pumps are introduced, and the treatment measures for axial force are summarized, providing reference for centrifugal pump designer, project engineers and operators to deal with the axial force of centrifugal pump.

Key words: vertical multistage pump, axial force, thrust bearing, countermeasure