Development of a pedal operated seed cleaner for seeds with diameter size range of 6.6 – 18mm

Abstract

In Uganda, legumes and grains seeds are mainly cleaned using traditional methods of manual winnowing and conventional screening which are inefficient, labour intensive and time consuming. The available imported seed cleaners are not only energy demanding but also expensive in terms of ownership, operation and maintenance. In an effort to provide a solution, a Pedal Operated Maize Grain Cleaner (PoM-Cleaner) was developed locally but was limited to maize cleaning. In this study, a Pedal Operated Seed Cleaner (PoS-Cleaner) was developed and its performance evaluated. The cleaner consists of a bicycle-like pedaling system, hopper, a centrifugal fan, and three cleaning sieves which include two inside interlocking sieves (one sieve fixed and the other adjustable); whose meshes can be adjusted to be larger than the size of the unclean seeds by longitudinally translating the second sieve to achieve the appropriate sieve gaps. This allows trapping of foreign impurities larger than the seeds. Appropriate engineering principles and methodologies were used in the sizing and construction of the machine. The POS-Cleaner was tested on cleaning maize grains, beans and groundnuts. Cleaning efficiencies of 95.09%, 87.61% and 81.67%, at cleaning rates of 571kg/h, 375kg/h and 375kg/h for maize grains, beans and groundnuts respectively were achieved. The POS-Cleaner presents a more viable cleaning option for smallholder farmers in rural and remote areas with no access to the national grid, therefore producing clean grains. This will eventually facilitate agricultural value addition and increase individual family incomes in the grain producing areas of Uganda.