DEVELOPMENT OF A VARIABLE SIZE NUT CRACKER

Abstract

In this work, a variable size nut cracking machine has been designed and constructed to improve the efficiency of shelling operation of quite a number of nuts. The machine is designed to be adaptable to the cracking requirements of some number of nuts, whose shell can be processed to brittleness. The machine performs two operations, shelling of the nut and separation of the shell from the nut. The machine comprises of a hopper, rectangular box housing the cracking drum and compression plate, and a two stage agitated separating tray (to sort the nut from the shell), all supported by a frame. The cracking drum, which is driven by a v-belt connected to an electric motor, also provide the agitation to the separating tray via a v-belt connected a cam mounted shaft that helps push the tray against stationary springs to return the tray to its initial position upon the dwell of the cam. The continual return and compression of the tray against the spring subjects the tray to a vibration needed to enhance the travelling of the shell-nut mixture over it. The machine was tested with palm kernel, the strongest of the class of nuts it was designed to crack; the machine yields a cracking efficiency of 87%. The whole kernel recovery of the machine stands at a magnificent value of 87%. The machine performed satisfactorily.