Design and Fabrication of Melon Shelling and Separating Machine
Abstract
Although there are several designs on melon shelling machines, it is observed that these available designs in the market are relatively more sophisticated and expensive hence they are not affordable to majority of local farmers. The aim of this work is to design and fabricate cheap and affordable melon shelling and separating machine which can effectively shell all the species of melon through electric powered operation, with little or no technical skill required for its operation and at a cheap affordable price using local available materials. The machine was evaluated to determine the percentage number of shelled and unshelled melon seeds, shelled but broken seeds and the partially shelled melon seeds at 7% and 10% wb and concave speeds of 750, 950 and 1200 rpm. At concave speeds of 750, 950 and 1200 rpm, and moisture content (MC) of 7% wb, the calculated shelling capacity of the Sheller were 65, 128 and 148kg/h respectively. The cleaning capacity was 52kg/h, 85kg/h and 85kg/h respectively. When the MC of the melon seeds was increased to 10% wb by sprinkling the seeds with water and allowing it to dry by natural air, the shelling capacity became 53kg/h, 88kg/h and 145kg/h for the concave speeds of 750, 950 and 1200 rpm respectively. At 10% MC the cleaning capacity reduced from 53kg/h to 39kg/h at the speed of 750rpm and from 85kg/h to 66kg/h at the speed of 950rpm. However, at 1200rpm the cleaning capacity increased from 85kg/h to 109kg/h. The fraction of fully shelled melon seeds at mc of 7% wb using the concave speeds of 750, 950 and 1200rpm were 54%, 45% and 45%, while percentage of broken seeds were 85, 95 and 97%, and the number of partially shelled seeds were 42%, 54% and 54%; the percentage number of unshelled seeds were 3.9%, 1% and 0.3%. Moreover, , at the MC 10% wb using the same concave speeds of 750, 950 and 1200rpm the percentage number of broken seeds reduced to 0.8%, 2.3% and 8.9%. Based on this result, the machine is found to be very effective in peeling melon seeds at 10% M.C and at a concave speed of 1200rpm since the ratio of the number of unshelled melon seeds to the quantity in each sample is very negligible.
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Introduction
1.1 Melon cultivation:
Melon (Citrullus Vulgans), is a common vegetable crop which is widely cultivated in Nigeria (Fadamoro, 1999; Oluwale and Adedeji, 2012). Oni, (2005) classified melon as a legume crop because it has the capacity of preventing or controlling the growth of weeds on the farm and can add Nitrogen to the soil through the process of Nitrogen fixation. Melon can normally be planted twice in a year - during the rainy season and during the dry season and that it is most common in Northern parts of Nigeria particularly Kano, Kaduna and Jos. After harvesting melon, the seeds are carefully removed from the pod and washed very well with water. Solar energy is then used in the conventional way to dry them (Carter, 2002, Ogwo and Oranu, 2006).
The processing of melon is imperative to further diversify its use. This includes shelling, washing, coring, drying, fermenting, drying and extracting of oil. Shelling involves removing the outermost part (husk) from the melon kernel. Here, the seed is separated from the spiny husk. This operation can be carried out in the field or at the storage environment (Nwakire et al. 2011).
Conclusion
A simple melon seed shelling and separating machine has been fabricated, preliminary test were carried out on the melon sheller and separator to ascertain its performance. The cost, safety, maintainability, durability and efficiency were critically taken into consideration during the design. The results of the tests carried out on the machine showed a very remarkable and promising success as far as the functional requirement of the melon sheller is concerned. The machine is sustainable from the fact that the materials used for its fabrication were locally sourced, thus, the spare parts are locally available.