Abstract
A drying machine for selected vegetable extracts under varying temperatures and moisture content was developed in this work. The design of the machine was carried out with Autodesk Inventor 2018 software after careful design calculations and considerations. The machine consists of sub-components: belt and pulley system, dryer enclosure, conveyor assembly, air fans, heat sources, product feeder and other accessories. Considering the power transmission system, the total power transmitted by the belt and pulley system was 72.53 W. The speed of the dryer shaft and length of the belt that connect the motor and dryer pulleys together were estimated to be 60 rpm and 957.94 mm respectively with tension values of 176.77 N (T1) and 22.46 N (T2) on tight and slack sides of the belt. The designed value for the diameter of the dryer shaft for full strength was estimated as 10.7 mm. In the conveyor belt analysis; the corrected length, corrected factor, belt speed, belt capacity, belt power and pressure loss through the belt were estimated to be 1070 mm, 1.035, 0.47 m/s, 0.279 kg/s, 11.57 W and 450 pa respectively. The mass of the load per unit length of the belt was 2.14 kg/m while the maximum belt tension and feed flow rate on the conveyor belt which the machine can handle were 388.4 N and 1.01 kg/s (3636 kg/hr) respectively. In the dying process analysis; the drying rate of 0.856 kg/s at the fresh air rate of 9.51 kg/s was obtained. The thermal energy requirement of the heating chamber was 1352.3 W over the heat transfer area of 4.55×10-4 m2. The total electrical power of the conveyor dryer was 46.11 W while the overall efficiency of the machine estimated was 71.64 %.