DEVELOPMENT A PROTOTYPE FOR IMPROVING THE PERFORMANCE OF THE CLEANING UNIT IN COMBINE HARVESTING MACHINE

Abstract

Seed cleaning is an important operation in a number of processes connected with the handling of seed after harvest. The goals of the current research were developing of a laboratory unit for cleaning the wheat crops in combine harvesting machine. The laboratory model was manufactured to simulate and study the aerodynamic characteristics of air and test the performance of the developed cleaning unit at four aerodynamic suction velocities 5.9, 8.5, 11.6 and 14.9 m/s., three feed rates 3, 5, and 7 kg/min, two rotational speed 245 and 350 r.p.m to operate the screens, two shapes for suction part rectangular and circle and three slope angles for screens 5°, 10° and 15° with three replicates. The results indicated that the average of minimum specific energy was 8.46 kw.h.ton-1 at 5.9 m/saerodynamic suction velocity, 5o screen slope, 0.42 ton/h feed-rate, 245 rpm rotational speed and circle shape of suction tube. Also, the maximum cleanliness was 99.41 % for aerodynamic suction velocity of 14.9 m.s-1, slope of the screen was 15o, at feed-rate of 3 kg.min-1, rotational speed of 245 rpm and rectangular shape of suction tube. On the other hand, the minimum grain losses percent was 0.53% at aerodynamic suction velocity of 5.9 m.s-1, 5o slope of the screen, 3 kg.min-1feed-rate, 245 rpm rotational speed and circle shape.