Centrifugal pumps types are primarily based on the manner in which the pumps are installed on the site.
These types of centrifugal pumps are installed and operated with the impeller axis of rotation parallel to the ground level. This is the most common type of installation. For such installation, the suction side piping arrangement is very critical in ensuring smooth operation of the pump. The prime mover (motor), is either coupled to the shaft of the pump, or the impeller is directly mounted on the motor shaft (mono block type).
In vertical type execution, the impeller axis is perpendicular to the ground level. The motor is mounted on the top of the shaft. Such type of pump can be closely coupled motor shaft or extended shaft pumps with distance of the hydraulic components as much as 12 metres from the support plate. These pumps are very popular in corrosive application or when the NPSH conditions are critical since the hydraulic components can be completely submerged in the liquid.
SUBMERSIBLE MOTOR PUMPS
Submersible motor pumps are installed with the entire pump assembly, including the motor, is completely submerged inside the liquid to be pumped. In such installations, the motor is made of special leak proof construction and the impeller is directly mounted on the motor shaft with shaft sealing between the electric and the hydraulic components. Since the pump assembly is completely submerged inside the liquid, no pump parts are visible on the ground level. It also eliminates noise arising from pump operation.