DESIGN CONSIDERATIONS OF A COMBINATION MACHINE FOR CHOPPING AND MILLING ARUNDO DONAX (PART I)

Abstract

The aim of present work was to carry out theoretical analysis to design to design a combination machine to be suitable for chopping and milling Arundo donax plants and then to use the design considerations afterward to manufacture and evaluate the performance of the combination machine to reach up the optimum operating parameters. The design considerations included estimation of the following parameters: number of knives on the cutter-head, cutter-head speed, feed rolls speed and Arundo donax density in the feeding throat. The design considerations were evaluated taking into consideration the following indicators: theoretical cut length, theoretical capacity and required total power; furthermore determination of cutter-head shaft diameter as well as hammer mill shaft diameter. The design results reveal that the highest values of theoretical cut length and theoretical capacity were (29.14 mm and 756 kg/h) respectively, while the lowest values of chopping and milling units power were (9.54 and 20.17 kW), respectively and the values of cutter-head shaft diameter and hammer mill shaft diameter were (50 and 60 mm), respectively under the following conditions: number of knives on the cutter-head of 2 knife, cutter-head speed of maximum 1400 rpm and Arundo donax density in the feeding throat of 6.18 kg/m3 with adjusting feed rolls speed of 1.36 m/s.