VERTICAL TURNINE PUMPS
A vertical turbine pump, also called a deep well turbine pump, is a vertical axis centrifugal or mixed flow type pump comprising of stages which accommodate rotating impellers and stationary bowls possessing guide vanes. The bowl assemblies are nearly always located beneath the water surface and hence the deep-well turbine pumps are adapted to seasonal fluctuations in water level in the well. They are specially adapted to tube wells where the pumping water level is below the practical limits of a volute centrifugal pump. The comparatively small diameter of turbine pumps suit their installation in tubewells.
Vertical turbine pumps are adapted to high lifts and have high efficiencies under optimum operating conditions. They have, however, higher initial cost and are more difficult to install and repair, as compared to volute pumps.
As with all centrifugal pumps, the pressure head developed depends on the diameter of the impeller and the speed at which it is rotated. In the deep-well turbine pump, the diameter of the bowl and that of the impeller inside it are restricted by the relatively small diameter of the tubewell. Hence, the pressure head developed by a single impeller is not large. Additional head is obtained by adding more bowl assemblies or stages.