When starting multistage centrifugal pump, the water has not yet had time to spray into the channel, and the drive shaft starts to move like a pendulum. The operator quickly stops. On-site analysis, first of all, it is considered that the installation of the horizontal multistage centrifugal pump is unqualified. From the assembly workshop, an experienced engineer was transferred to re-install and calibrate one unit, and the test drive was again tested. The drive shaft was still vibrating. Later, it was considered that the shaft was not stiff enough, especially the vibration of the top one was the most powerful. Then the upper shaft is changed from φ70 to φ90. After carefully replacing the last transmission shaft, the vibration condition is improved, but the vibration is still obvious. After repeated fiddling, the problem remains unresolved. Later, by calculating and reviewing the strength and stiffness of the drive shaft, it turned out that the transmission model was incorrect. The reason is that the torsional stiffness is not enough. An effective measure to solve the problem of insufficient torsional stiffness is to reduce the span of the two points of the shaft. After the correction, the driving test was carried out and the upper drive shaft no longer vibrated. Then the bearing brackets were added to the second and third transmissions in turn, and the final problem was solved.
Changsha Zoomlian Pump's Engineer suggests:
1. Do not just simplify the structure and reducing costs.
2. When solving the problem of pump station failure, it must be theoretically calculated and analyzed to provide guidance and theoretical basis for improvement measures.
