Design, development and testing of hand-operated decorticator for Jatropha fruit

Abstract

Jatropha fruit, presently dehulled manually in the absence of a suitable mechanical device. Manual decortications of Jatropha fruit for the purpose of extracting seeds is a time consuming and tedious operation. A small, continuous, hand-operated machine, specially designed and constructed for decortications of Jatropha fruits has been done and evaluated for performance parameters. The major components of the machine are the frame, hopper, decorticating chamber, concave sieve, rotating blades, discharge outlet and a vibrating separator with sieve to separate seed and shell. The performance parameters of the machine including Percentage of whole seed, broken seed, partially shelled fruit, unshelled fruit, machine efficiency and decortications efficiency, were evaluated at four different moisture content (7.97%, 10.53%, 13.09% and 15.65% d.b.) with a combinations of concave clearance (18 mm, 21 mm, 24 mm and 27 mm) between concave sieve and rotating blades. The best set of conditions under which the decorticator can be operated is at fruit moisture content of 7.97% d.b. with concave clearance of 21 mm between the concave and the blade at which the maximum whole seeds of 67.94% can be achieved and machine efficiency of 90.96% can be obtained. All materials used for fabricating the components were brought from sourced locally. This design is preferred, because of its rapid operation, low human-energy expenditure, low breakage factor for the seed as well as relatively little dust being emitted during shelling; hence leading to a relatively-healthier local atmosphere for the operator.