Development of a rice cleaner cum grader for cottage industry processors in Nigeria

The consumption of locally processed rice in Nigeria has been on the increase because of its high nutritive values and favourable government policies. There have been issues with the wide acceptability of this product as a result of the physical quality of the milled rice. A high percentage of broken grains and impurities are the concern associated with the traditional methods of processing rice. some physical and aerodynamics properties of five varieties of n of the developed machine. The machine with a blower revolving of 240 rpm to produce air velocity of 4.6 separating the contaminants. For an effective grading, apertures diameter of 3, 5.5 and 7 mm were selected for the bottom, intermediate and top sieves of the machine. Parboiled milled rice produced from single-pass steel huller was fed into the machine and tested at tilt angles of 2, 3, 4, 5 and 6o for the intermediate sieve at blower inclinations of 0 and 5o . The results obtained showed the spherical mean of range 2.85 to 3.45 mm, with sphere city existing within 0.41 to 0.50 and terminal velocity from 4.81 to 6.36ms-1. The machine has cleaning efficiency that ranged from 63.97 – 85.38%, with FARO 44 having the highest. The efficiency of grain grading was from 71.78 - 94.29% and the highest was obtained in ITA 150 at a blower inclination angle of 5o . The capacity obtained from the machine ranged from 1000 – 1200 kghr-1. Better machine performance was obtained at blower inclination of 5 o except for FARO52. The adoption of this machine after milling has upgraded cottage processed rice quality from grade 2 to grade 1. Keyword: Rice Variety, Value-Chain, Tilt Angle, Blower Inclination, Sieving and Grading