DEVELOPMENT an‎d EVALUATION OF A LOCAL INDUSTRIAL MACHINE FOR WATERMELON SEEDS EXTRACTION Shreen, F.A. Mohamed.

The overall objective of the present investigation was to modify and evaluate the performance of a local manufactured machine for extracting seeds from watermelon seeds. There were two problems facing the traditional machine, firstly, the seeds which extricated by the machine must be washed and the second problem was the increase of seeds damage ratio. To overcome these problems washing unit was added in the end of separating stage. The primary experiments show that the principle part which caused the increase in seed damage was crush drum. Then; theoretical studies were carried out to determine the permissible feed rate, knives number on crash drum, drum speed and clearance between crash drum and concave. The results indicated that the maximum value of cleaning efficiency was 93.8% with concave clearance of 3 cm, drum speed of 0.46 m/sec, knives number of 14 and feed rate of 60 kg/min. Too, the minimum value of 79.0% was obtained under concave clearance of 1 cm, drum speed of 1.4m/s, knives number of 6 and feed rate of 120kg/min. The Maximum cost value of 1052 LE/ton was achieved at feeding rate of 60 kg/min and drum speed of 1.4m/s. While, the least cost was estimated at 120 kg/min feed rate for all different ranges of drum speed. The developed unit saved about 61.4 % and the cost per ton was 1052LE compared to the manual extraction.