EFFECT OF PULLEY SIZE VARIATION ON THE PERFORMANCE OF AN ARMFIELD-FT28 SCREW PRESS IN VEGETABLE OIL EXTRACTION

The relationship between operating parameters namely press worm shaft speed, feed rate and choke clearance and dependent variables which included percentage oil yield, cake yield, oil extraction efficiency, material loss and throughput capacity was investigated while mechanically expressing oil from the Mai Bargo variety groundnut seeds (Arachis hypogaea L.). A 3 ×3×5 factorial concept fitted into completely randomized design was used in three replications. The speed was varied over   64.6,56.6,40.6 and 32.6 rpm using pulley arrangement, choke clearance was varied at three levels of 2.0, 4.0, and 6.0 mm using feeler type gauges. Calibration markings were made on the press once these desired settings where attained. The product feed rate was at Pre-calibrated values of 500,1000 and 1500g/minutes. Data collected from performance evaluation of the screw press were analyzed through analysis of variance (ANOVA) using Statistical analysis system (SAS). More comparison mean was further analyzed to know the level of significant using Tukey’s test.  Throughput capacity of 3.20kg/h was obtained at 40.6rpm worm speed of operation, 2.00mm of choke clearance   and1500g/min feed rate. The results showed that worm speed of operation, choke clearance and feed rate had significant influence on percentage oil yield. Pulley diameter of 312.5 mm gave the best speed for the Optimal percentage oil yield oil of 32.20% at throughput capacity of 3.20kg/h and at maximum feed rate. The determination co-efficient (R2) of these models were 0.929 and 0.973 for liner and quadratic respectively, which means that the models had a favorably fitting degree. The result of this study would be useful for rational design and development of groundnut oil screw press