What may cause vertical multistage centrifugal pump shaft fracture?
The cause of shaft fracture of vertical multistage centrifugal pump is:1) the problem of the shaft itself:A) the structure design of the pump shaft is not reasonable (not reserved unloading groove), or heat treatment on the axis of improper residual stress, finally in a position to the existence of the axial stress concentration, causes the pump to run for a long time the rear axle will appear crack, crack spreading until shaft fracture.
(b) the actual operating conditions of the pump deviate from the design conditions too much (for example, the actual flow of the pump is too large or too small), which leads to the deterioration of the stress on the pump shaft and causes large vibration at the same time.Multistage centrifugal pump: centrifugal pump is a kind, but also rely on the rotation of the impeller in the acquisition of centrifugal force. The pump is more than two will have the same function together, the first level of medium pressure and second level of import relief is second level of medium pressure and export import relief level third interlinked, so the institutions formed a series of multistage centrifugal pump. The significance of multistage centrifugal pumps is to increase the set pressure. The vertical multistage centrifugal pump has the characteristics of compact structure, small size, light weight, low noise, remarkable energy saving, convenient overhaul and so on.
B) the strength of the pump shaft itself is not enough, and the safety factor used in the strength calculation is too small (usually over 3.5).C) there are internal defects in the pump shaft material (such as trachoma, cracks, etc.).2) axis external causes:A) improper assembly of the pump causing the pump shaft to be subjected to other external forces.
