Shaft and column stretch in enclosed tube vertical turbine pumps result from mechanical and hydraulic forces, impacting performance, alignment, and efficiency. Shaft stretch occurs due to tensile forces on the shaft, while column stretch results from compressive forces acting on the pump column. Factors such as load transmission, material properties, and operating conditions influence these effects. Proper design, material selection, and preloaded bearings help mitigate these issues, ensuring optimal pump operation and longevity by maintaining the correct impeller lateral positioning, so it runs at the appropriate distance from the bottom of the bowl at the pump design condition.
