To improve the performance of the locally manufactured threshing machines, a feeding system wasdevelopedto use with it. The aim of this work is to reduce both the threshing costs and the injuries to the laborers.
The main objectives of this study are:
1-Develop a feeding system for threshing machine.
2-Evaluat the performance of the threshing machinesbefore modification at three moisture contents for wheat crop 17.2, 15.2 and 13.4 % and four drum speeds 700, 800, 900 and 1000 rpm (27.47, 31.4, 35.3 and 39.25 m/s) .
3-Test the threshing machinesafter modification under the same conditions at different angels of conveyor belt of 17.5, 20, 23 and 26 degree.
The experimental results showed that the performance of a threshing machine after modification is better than before modification. The value of the feeding rate after modification increased about 26% than before modification. It was of 2.28 ton/h compared to 1.68 ton/h before modification. Threshing efficiency of 99.50 %, cleaning efficiency of 99.70 %, unthreshed grain losses of 0.50 %, grain losses in straw of 0.30 %, grain damage of 0.65 %, cutting length of straw of 1.20 cm, total grain losses of 5.37 kg/ton were also recorded before modification. The operation cost was 22.8LE / ton and the threshing cost was 36.4 LE / tonafter the addition of the costs of lost grains at drum speed of 1000 rpm. These results were obtained at moisture content of 13.4 %, and conveyor belt angle of 20 degree.
On the other hand the results before modification threshing efficiency it was of 98.20 %, cleaning efficiency of 98.40 %, unthreshed grain losses 1.80 %, grain losses in straw of 1.00 %, grain damage of 2.10 %, cutting length of straw of 1.8 cm, total grain losses of 18.13 kg/ton were recorded. The operation cost was 33.33 LE/ton and threshing cost was 79.2 LE/tonafter the addition of the costs of lost grains at drum speed of 1000 rpm and moisture content of 13.4 %. The specific energies were 11.3 and 8.1 kW.h/ton before and after modification at the same previous conditions.