Abstract:
Winnowing process (removal of the dried seed shells) required to establish quality to cocoa beans products. The machines for this process are imported ones and importation cost is too high and unaffordable to some new investors, who are ready to go into cocoa processing. The existing firms or industries find running cost of this machine exorbitant. Hence, the development of a portable winnowing machine made from a locally sourced material which was produced at a relatively low cost and performance evaluation was carried out on the fabricated winnower. The major components of this system are spring element, shell aspirator duct, return nibs blower, vibrator, shell aspiration suction fan, the crushing chamber, linear reciprocating sieving unit, the supporting frame, electric gear motor and the beans’ silo with metering auger unit. Major designed components and their designed values are: the volume of the cocoa receptor is 0.00835 𝑚3 ; volume of silo is 0.03 𝑚3 ; power to drive auger shaft - 2.5 kW; volume of inlet hopper is 0.016 𝑚3; power required for crushing chamber - 1.5 kW, required centrifugal force is 4.8 𝑁. Capacity of suction fan and blower are 0.5 kW and 0.02 kW respectively. The designed capacity of this winnower was 0.6 tonnes (600 kg) per hour. This locally designed and fabricated winnower was tested and it was found to have efficiency of 75%, with power rating of 5.06 kW while it has a capacity of 0.6 tonne per hour with a steady weight of 220 kg and dimensions of 2603 𝑚𝑚 ×2345 𝑚𝑚 ×985 𝑚𝑚 . The production cost considering purchased materials, fabrication cost, machinery cost, and labour cost and bought out components cost amounted to four hundred and five thousand six hundred and fifty naira (₦405.650). Performance evaluation of the machine shows that 8.95% of the beans were unbroken, 8.68% were broken but shells not removed, 75.02% were properly broken with their shells well removed and qualified for further processing while 7.35% was recorded as losses during the processing. If losses, and other beans unbroken or broken but shell not removed are worked upon, the efficiency of this machine in no doubt will increase
