Design of an Automated Powered Peanut Shelling Machine

Groundnut is predominantly grown by communal farmers in natural farming regions 2-4 of Zimbabwe. The price of shelled kernel is approximately double that of pod. Hand shelling of peanuts is a time consuming and laborious process which is mostly used in the remote areas in Zimbabwe. Manual shelling of peanuts using “Manual Sheller’s” has been adopted to reduce the time invested in hand shelling. These machines have high defective rates of almost 50% which reduce the overall gain achieved by the farmer after harvesting. As a result, the need has risen to design an automated powered peanut Sheller machine automated using a Program Logic Controller and having a servomotor as its actuator to solve the high labour, huge amounts of time lost through shelling and the low efficiency of previous Sheller designs. First hand results were obtained in this project by determining the crushing force required to shell peanuts at approximately 10% moisture content. Regression models were then used to standardise these results to enhance accuracy. Shelling throughput, automatic gap adjustment, shelling efficiency, mechanical damage are some of the parameters used to determine the overall performance of the peanut Sheller. However exhaustive research on peanut engineering properties has to be done in future to lay out a foundation for improved future designs.