Design and construction of an improved multi-crop engine powered threshing and separation machine for legumes.

Abstract

Threshing is one of the most important activities carried out in primary processing of legumes. It is aimed at dislodging seeds/grains from the pods and these legumes include common beans, soya beans and peas. Most farmers in Uganda grow a number of legumes at different seasons and these crops all under the primary processing of threshing in which they majorly dependent elementary methods of threshing which are Labour intensive, time consuming and wasteful in that seeds get damaged. However, the existing machines are only limited to one crop causing machine redundancy and have low cleaning efficiency thus relying on manual power for cleaning. The machine was aimed at minimizing the problem of machine idleness and improving the efficiency of seed separation from physical contaminants putting into consideration the physical properties of all legumes. In this project, an optimum performance was obtained at feed rate of 0.025Kg/s giving TE=98.9%, CE=89,5% MD=0.4% and total Machine output of 52Kg/hr. for soya beans, 0.042Kg/s giving TE=98.7%, MD-0.66% and total Machine output of 69Kg/hr. for common beans. However, there is a problem of clogging at the chaff outlet, machine immobility and bulkiness that still needs more attention. In order to maximize the cleaning efficiency of the machine, option of incorporating a shaking sieve should be considered. Furthermore, ground tyres should adopted to permit machine mobility.