This is an Invited Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 5 (2003): A. Tabatabaeefar, H. Aghagoolzadeh, and H. Mobli. Design and Development of an Auxiliary Chickpea Second Sieving and Grading Machine. Vol. V. December 2003.

Sieving and grading are two final operations of high quality grain production. Farmers in Iran normally winnow chickpea by hand, which leaves a large amount of debris among the chickpea. To correct this problem, a machine was designed and developed at Tehran University to sieve and grade chickpea a second time. A low price, easy maintenance and usage, and technology appropriate for Iranian farmers were important considerations in the development of the machine. The following steps were taken during the design of the machine: Physical properties, terminal velocity, and coefficient of friction of five different varieties of Iranian chickpea: Jam, Philip, Bivanij, ILC-482 and ILC-12-60-31--were determined. The following parameters and factors affecting machine operation were determined. The arithmetic mean diameter was 6.7-9.7 mm with an average of 7.8 mm. The terminal velocity of a whole chickpea was 10-15 m/s, with an average of 12.6 m/s. For the dried leaves and stems, the averages were 3.0 m/s and 5.5 m/s, respectively. The minimum coefficient of friction occurred on galvanized steel and was 0.28, and the maximum coefficient of friction value of 0.33 occurred on fiberglass. The cleaning, grading, and overall efficiency of the machine were evaluated with 2 kg of hand-cleaned peas (debris-free) mixed with 15 grams chaff and stem and 100 grams of clods and stones. The cleaning efficiency of the whole chickpea was 93 % and the debris was 91 %. Overall, the machine efficiency was 84 %.