ABSTRACT
In this work, a household wet beans de-hulling and separation machine was designed and fabricated to take care of the difficulty involved/faced during manual washing/peeling of beans and separation.
The machine was fabricated using locally sourced materials which are readily available around us. The machine parts include: hopper, conveyor shaft, peeling plates and a separation chamber. The beans is soaked in water between 5 to 10 minutes, then drained and charged into the hopper which is then conveyed to the peeling plates. The peeling plates are two in number which are about 5 to 6 mm apart; where one is stationary and the other is dynamic. As the beans is conveyed in between the plates, the dynamic plate rubs the beans against the stationary plate and with the help of friction, the peels are rubbed off the beans. Separation is done by a roller. This roller is within the separation unit/chamber. The chamber is guided in both sides with plates leaving only a small space that can only pass peels. As the beans and peels fall on the roller, it drags the peels down into the peel/chaff chamber, then the clean beans dances on the roller towards the outlet and it’s collected.
After the fabrication, some tests were carried out which involved two persons and the machine. 0.2 liters of beans (one tin of medium tomato paste container) containing about 725 seeds and weighing about 178g were measured to person A and person B respectively to wash manually and timed. At the end of 5 trials respectively, it was shown from result obtained that person A could complete the task of peeling and separation for an average time of 9.8 minutes while person B could complete the task for an average time of 10.9 minutes. The machine was then tested 5 times as well with the same measure of beans and was seen to complete the task at an average time of 5.6 minutes. This in other words shows that it will take the machine less time to complete the task of peeling and de-hulling compared to humans. It should be noted that the persons involved in this test are into Akara business (beans cake) and as such are professionals in washing beans. Another test was carried out repeatedly for eight (8) times. After each test, the total number of beans fed in, the number of beans peeled, the number of unpeeled beans and the number of lost beans were recorded and tabulated. The efficiency based on through put is 95.6% and the efficiency base on peeling is 91.5%. Therefore, the average efficiency of the machine was calculated and found to be 93.55%.
The fabricated machine worked and was able to address the difficulty in processing of beans.
