Development o f a minimum cost small scale cocoa de-pulping machine.

Abstract

Cocoa is one of the most important cash crops grown in Uganda after coffee, tea with a total land area of 25000 hectares covered by cocoa plants (www.monitor.co.ug). The crop grows in a limited geographical zone of about 200 to the north and south of the Equator (Bujjsse (2006) and Angelo, (2010)). It is widely grown in various districts in Uganda including: Bundibugyo, Mukono, Jinja, Kamuli, Buikwe, Masindi, Mayuge, Iganga and Kayunga districts on small scale. Harvesting is carried out by cutting the pod stalks with knives. The harvested pods are transported to the farmer's home, opened, seeds removed and placed in baskets to allow fermentation to take place and then dried. The above processes are accompanied by high quantitative and qualitative losses, and are highly tedious, labor intensive, time consuming. The depulping machine was designed and constructed by first sizing the components through analysis of forces acting on the components, material selection, fabricated and assembled. The selected materials were those which would withstand the applied forces in order to avoid failure of the components during operation of the cocoa seed depulper. The depulping capacity of the prototype was 3.44kg/min and an average depulping efficiency of 70%, and percentage loss of 7.64% obtained by carrying out two tests at rated engine speed of 1420rpm of a 3HP motor. The prototype has limitations of immobility, high power requirement and needs frequent cleaning. The prototype was produce at a cost 651,250 UGX. Economic analysis of prototype was carried out using the Net Present Value and Profitability Index analysis to determine its viability. The profitability index was 1.78 which shows the project was viable.