Abstract
Abstract
The need for the use of shelling machines for an average value of 220, 000 tons of unshelled castor seeds produced annually in the Northern Nigerian has been stresses. The traditional sheller has very low output capacity and high energy demand is greatly insufficient. Lack of locally developed castor seed sheller and high cost of imported one necessitate the development of the machine. Design related properties of castor seeds facilitated the design of some of the machine components. This work involves the design, fabrication and evaluation of the performance of castor seeds (Riscinus commnis) Institute for Agricultural Research Samaru (IAR) shelling machine. The machine was designed to have a total power requirement of 3.5 hp and shell selected variety of castor seeds at small scale level suitable for small and medium scale castor seeds produces. The prototype machine was designed, fabricated and assembled in the Department of Agricultural and Bio – Resources Engineering, Ahmadu Bello University, Zaria. The machine consists of a hopper, shelling cylinder, concave with grate, bearing, bolt and nuts, cleaning unit, pulley, grain outlet, shaft, prime mover seat and frame The developed machine was evaluated using factorial experiment with five levels of cylinder speed (220, 240, 260, 280 and 300 rpm), three levels of concave clearance (15, 20, and 28 mm) and three cylinder types (metal, rubber and wood) arranged in 5 ×3 ×3 completely randomized design (CRD). Data collected for shelling efficiency, cleaning efficiency, mechanical damage, scattered grain and output capacity were analyzed using statistical analysis software SAS. The result from the evaluation of the machine showed that the best cylinder types were metal, followed by rubber and wood. The machine found to perform better at cylinder speed of 220 rpm, cylinder concave clearance 15 mm with metal cylinder. When operate at this parameters the machine gives the maximum values for the shelling efficiency, cleaning efficiency, mechanical grain damage, scattered grains and output capacity of 82.25, 75.14, 6.04, 2.89% and 12.19 kg/h, respectively.
Keywords: Development; castor seed, capacity, shelling machine, shelling efficiency, cleaning efficiency

Key words: Keywords: Development; castor seed, capacity, shelling machine, shelling efficiency, cleaning efficiency