Development and performance evaluation of impact bambara groundnut sheller

A centrifugal bambara groundnut shelter was designed, constructed and evaluated. The sheller consists of a feed hopper with a flow rate control device, shelling unit. separating unit and power system. Nine different impellers were used for the investigation at three different pod moisture contents. Results of the performance tests were examined using a 3 x 3 x 3 factorial design with moisture content, impeller slot angulations and number of impeller slots as variables. Results showed that moisture content, impeller slot angulations, number of impeller slots and interaction between these variables statistically affected the performance indicators (shelling efficiency, percentage of breakage, percentage of partially shelled pods, percentage of unshelled pods and winnowing efficiency) at the significance level of 5%. The forward facing impeller with eight slots gave the best performance of 96% shelling efficiency, 3.4% breakage, 0.6% partially shelled pods. No unshelled pods were recorded, and winnowing efficiency of 97.3% was recorded at an average feed rate of 215.8 kg h(-1).