Design and construction of a multi grain cleaner.

Abstract

Rice and maize, contribute an important element in food industry and food security in Uganda. Grains are consumed in homes; schools, hospitals, among the armed forces, rehabilitation centers, refugee camps institutions, health centers, due to the large quantity of carbohydrates, proteins, vitamins and fats contained in the kernels. According to FAO, 1994 -10% grain losses occur due to poor post-harvest handling. Harvested grains have straw, chaff, sand, rocks, dust, damaged seed stones: cobs husks- and many others. The foreign matter in grains adversely affects subsequent storage and processing conditions affecting the nutritional and market value. Cleaning by traditional winnowing technology leaves the grain contaminated with foreign matter posing a reduction in farmer's income Smallholder farmers in Uganda use traditional post-harvest handling methods that expose grain to contamination by foreign matter. Manually grain cleaning: methods are inefficient, labor intensive and depend on natural wind which leaves of the gain contaminated, To overcome this problem, this study its main objective to design and construct a multi grain cleaner as -well as- testing of the constructed machine and the economic evaluation of the multi grain cleaner. It is aimed to enable the small holder farmers to enhance the and quantity of their consumable grain and enhancing (the: nutritional and market -value, with significant reduction in the quantitative post-harvest losses thus enhancing the country’s. food security status. The grains. considered in this study were rice and maize Various components of multigrain cleaner were designed using basic engineering principles and some physical properties of grains such as size, density, (760kg/m3,), moisture content, (160/0 dry basis), angle of repose, (28) and weight of the grain; The trays sieves perforations were obtained to be 11mm and 6.0mm for first and second sieves -respectively. The performance of multi grain cleaner was evaluated in terms of machine output, cleaning efficiency, cleaning loss and mechanical damage for machine output and found. as 748,44kg/hr, 7406 7.54% and 2,275% respectively. Key words: multi grain, cleaning, stratifying efficiency, cleaning output, density, size, chaff, Contaminants