Design and construction of an improved groundnut sheller.

Abstract

In Uganda, traditional methods are used for shelling groundnuts. These include, beating with sticks on a flat surface and the use of hands. These are all laborious. There are many mechanical shellers on the market that can shell at a rate of up to six bags every hour. The hand cracked, the tyre manual type and the motorized ones are quite expensive for the farmers and are also associated with high levels of kernel breakage. Therefore, the objective of this study was to design and construct an improved manually operated groundnut sheller aimed at addressing the problem of kernel breakage by ensuring that the right groundnut size is shelled by the rightful sieve and clearance at the cheapest cost possible. This machine presented a cheap, effective, sustainable and affordable tool to small scale processers and farmers for shelling groundnuts without many limitations since it is actually be operated without a power source making it both cost effective and easy to be operated. (W.W., et al. 2002). The design of the various machine parts was carried out by analyzing forces acting on them. Force analysis led to selection of proper materials to withstand the forces to avoid failure. Mild steel of various sizes and grades were used, engineering drawings of the various components were drawn before the various components were constructed. Then prototype assembly was done last according to the engineering drawings. A fully functional prototype resulted after all the above operations. Testing of the prototype was carried out and the figures revealed that the machine had an efficiency of about 81% and a shelling capacity of 108kg/hour and the shelling loss of about 8.6%.