Impeller Design
As we have discussed earlier impeller is the most vital part of a centrifugal pump. Successful impellers have been developed with many years of analysis and developmental work. Fig.4 shows one of such impeller with its one shroud plate removed for better view of vanes.
These vanes are backward curved. Backward curved vanes have the blade angle less than 90 degree. Backward curved vanes are the most preferred vane type in the industry due to its self stabilizing power consumption characteristics. This means with increase in flow rate power consumption of the pump stabilizes after a limit. Forward and radial blades are less common in the industry. The eye configuration of the impeller shown is state of the art. This vane is extracted from a Kirloskar pump model. Such projecting eye section induces better swirl of flow and guarantees high negative pressure at the suction.