Design and fabrication of a manually operated rotary chili dryer.

Abstract

In Uganda, chili crop plays 8 great roles in earning a foreign exchange. It is grown as a subsistence crop and a cash crop with annual production of 300-700kg per year. It's majorly grown in Western region, West Nile, lira towns of Uganda, and Lango areas which include Ngai and Otwai sub counties in Oyam Abako, Barr and Amac sub-counties in lira. At post-harvest level, chili has been continuously not handled well which has led to the deterioration of its quality on the market. This is because of uncontrolled drying rate using natural methods of drying, and polythene papers. These methods are time wasting, energy sapping, injuries on chili and contamination due to prolonged handling by human beings. To overcome this problem, this study chose as its main objective to design and fabricate a manually operated rotary chili dryer. Different components of the rotary dryer were designed using fundamental engineering principles and some physical properties of chili such as size, density, and moisture content. The machine was then fabricated and assembled using methods like, welding, bolting, cutting, and boring. The machine was tested for both the drying rate and the heating efficiency. The drying required a period of 10 minutes to become steady at a rate of 2674g/min, with heat utilization factor of 0.89 and heating efficiency of 94%. The economic analysis using the discounting method of net present worth was used to determine the economic viability of the machine. The net present worth was Shs 2706910.871. Since NPVSO, then the machine was economically viable in a period of 5 years.