A METHOD FOR DESCRIBING SORTING EFFICIENCY INDEPENDENTLY OF FEED COMPOSITION

Commonly used expressions for sorting efficiency depend upon the compo sition of the material fed into the sorting machine. To describe the q uality of the sorted product, by these expressions, its relationship t o the feed composition is indeed essential. However, for general evalu ation sorting efficiency and for comparison between sorting methods an d machines, expressions that are not limited to a particular compositi on of the material are of great value. Such a method is proposed in th is paper. The approach is based on a ''sorting ratio curve'' which des cribes the sorting process with respect to the relevant property of th e sorted material. It is a curve that starts at 100% and ends at 0%, a nd the steeper the curve, the more accurate the sorting process. A met hod of determination and analysis of the sorting ratio curve is descri bed. Comparison tests were conducted with two different types of sorti ng machines and two different compositions of tomatoes. The machines d ivided the tomatoes into several classes (size ranges), and for each c lass, sorting ratio curves were composed. Analysis of the curves indic ated that the quality of the sorting operation of these two machines w as different.