Development of A Doum Palm Shelling Machine

Abstract The traditional method used in Nigeria for removing the shell of doum palm is tedious, consumes time and also result in musculoskeletal strains and cuts. Despite an extensive search, no published literature was available on the development of a machine to shell the nuts of doum palm. To overcome this problem, a power operated doum palm de-shelling machine was designed and developed to help improve efficiency and productivity in producing vegetable ivory, doum oil and these can profoundly influence the socio-economic security of doum palm farmers. The average dimension of the doum palm nuts for the outer and inner shell layer in the three principal axes (namely, length, width, and thickness) were found to be 48.11mm, 37.69mm, 33.28mm and 32.59mm, 26.70, 23.09 respectively and its equivalent geometric mean diameter, surface area and sphericity were also found to be 39.22mm, 4832.42mm2, 81.52% and 27.18mm, 2320.86mm2, 83.39% respectively. All materials used in the fabrication of this machine are of standard specification and locally sourced. The machine is powered by a 0.70 hp electric motor and when the doum palm nuts are fed into the hopper, they pass through to the shelling unit where the shells are removed without causing damage to the nuts. The shelling units comprises of an adjuster and a shelling drum. The doum palm nuts flows to the shelling drum and they make impact with the shelling drum and the walls of the adjuster giving rise to a very great impact force that eventually shells the doum palm nuts. The shelled doum palm nut thereafter falls out through the outlet. The adjuster is used to regulate the shelling unit to the desired fit for different sizes of the doum palm nuts to be shelled. Performances test analysis conducted show that the machine shelled the fruits without nut breakage and also that the machine capacity is 2376 nuts/hr and the shelling efficiency is 73%.