9.2.1 Centrifugal Pump
This is a radial machine in which fluid enter at its center and comes out from the periphery of a rotating element impeller. Side view of a centrifugal compressor having volute casting is shown in Fig.9.2.1(a)along with the nomenclature of its different parts. Impeller is made of a hub on which number of vanes are casted at equiangular position either on its one or bolt faces making passage for the fluid to glide through it for which the curvature of vanes is so designed that fluid flows without separation. Pump is known as single or double suction pump accordingly. A double suction pump is used where large mass flow rate is required. A shaft connects hub to motor and passes through the pump casing, which provides bearing for the shaft, see Fig.9.2.1(b). Seal is provided between casing and pump shaft to stop leakage od fluid.