· Centrifugal’ means directing or moving away from the axis.
· Centrifugal pumps use an impeller and a volute to create partial vacuum and discharge pressure necessary to move water through the casing.
· Radial flow and mixed flow pumps are commonly referred to as centrifugal pumps.
· The rotating element of a centrifugal pump is called impeller.
· An open impeller consists of a hub to which vanes are attached, while a closed impeller has plates or shrouds on each side of the vanes.
· The open impeller is less efficient compared to closed one but suited to handle liquids containing solids liquids containing solids.
· Radial pumps are provided with a spiral casing, often referred as a volute casing, which guides the flow from the impeller to the discharge pipe.
· A gradually increasing cross section around the casing tends to maintain a constant flow velocity within the casing.
· Some pumps have diffuser vanes between impeller exit and volute casing.
· Some pumps are double suction type
· Higher the pressure drop or head, lower is the flow rate.
