Development of a chopping machine for agricultural residue (a case study on grape trashes)

Abstract

The feeding mechanism was modified throughout using two drums to make the feeding uniform, distribute the dynamic load and, consequently, reduce the vibrations and increase the machine stability. The cutting system was modified throughout with a 5 kW 1,500 rpm electric motor on the frame to obtain four different operating speeds by using two fabricated pulleys with different diameters. A moving frame with three wheels was used instead of the fixed frame to facilitate the conveying, adjusting and operation of the chopper. The field experiments were conducted at four cutting speeds of 0.75, 1.19, 1.33 and 1.81 m/s as well as four feeding speeds of 0.28, 0.45, 0.75 and 1.22 m/s. Two different shapes of cutting knives (straight edged and serrated edge) were used for cutting the grape residuals. The cutting efficiency, productivity, cutting length and energy consumed compared with energy of local cutting tools were studied. The obtained results can be summarized as follows: Developing the feeding and cutting mechanisms of stationary Japanese chopper improved its performance by increasing its productivity and efficiency as well as decreasing cutting energy and chopping lengths. The maximum value of machine efficiency (93.16 %) and capacity (4.192 Mg/h) were accomplished with a feeding mechanism and cutterhead speeds of 1.22 and 1.88 m/s, respectively, using a serrated-edge. But, 0.28 m/s feeding mechanism speed and 1.88 m/s cutterhead speed gave the highest value of cutting efficiency (93.85 %). The minimum value of chopping length was 1.0 cm at feeding mechanism speed of 0.28 and 0.75 m/s using serrated-edge cutting knives while the lowest value of energy consumed was 0.776 kW h/Mg at 1.22 m/s feeding mechanism speed and cutterhead speed of 0.75 m/s. The optimum performance of the developed chopper was obtained at feeding mechanism speed of 0.28 m/s and cutterhead speed of 1.88 m/s by using serrated-edge cutting knives.