The S/S is a single open impeller centrifugal submersible drainage pump designed to function either partlytotally submerged. The impeller, mounted on the end of the drive shaft, consists of a back disk and blades. The fluid enters the rotating blade channel through the suction where it moves radially from the center outwards, acquiring energy both in the form of pressure and increased speed. When it leaves the impeller the fluid is conveye-towards the volute, Here part of the kinetic energy is transformed into pressure energy, and the fluid leaves the pump via the side delivery opening in the pump body Correct motor cooling is ensured by the fluid being pumped.