Abstract:
A local melon Depodding machine was designed, developed and evaluated for performance in extracting edible melon seeds, which are time-consuming and tedious operation. The design was based on the principle of impact force. The machine has a maximum capacity of 25kg of melon per batch powered by a 1.5kW, 1140 rpm single-phase electric motor. Some engineering properties necessary for melon pod depodding such as pod major, intermediate and minor diameters; weight, volume, unit density, impact velocity, and impact energy were determined and their values are0.94cm+1.77cm,11.50cm+1.74cm,11.44cm+1.98cm, 555.83g+283.26g, 891.62cm3+457.65cm3, 0.63g/cm3+0.014g/cm3, 2.36m/s and 2.776J respectively. The determined arithmetic, geometric, square and equivalent mean diameters are approximately the same(11.3cm+1.82cm). The performance characteristics of the machine include: depodding efficiency, material discharge efficiency and overall efficiency, were evaluated at six operating speeds (200 rpm, 250 rpm, 300 rpm, 350 rpm 370 rpm and 400 rpm). The Depodding efficiency varies between 32% and 74% , while seed discharge efficiency varies between 22% and 70%. The pulp discharge efficiency varies between 0.6% and 2.1%, while the overall efficiency varies between 7.2% and 53.4%. In all, the maximum efficiency occurred at the operating speed of 300 rpm. Statistical analysis conducted indicated that there were significant differences in the means of materials discharged from the machine at different machine speeds. The magnitudes of depodding efficiency (Ed), seed discharge efficiency (Es), material discharge efficiency (Emd) and overall efficiency (Eo) tested at all speeds were significantly different. Recommendations and prospects for future works were suggested. |
