Development and Testing of A Rice Destoning Machine

Abstract

A rice destoner was developed locally for separating stone from milled rice. The major components of the machine includes: reciprocating screen and blower as well as hopper. The separation of stone is achieved by the vertical and horizontal oscillation of the reciprocating screen which as result of the forced air flow (produced by the blower) through the machine causes the rice kernels to float on a cushion of air just above the screen. This, then allows the reciprocating screen to convey the more dense stones up the screen to a discharge chutes, thereby ensuring the separation of the stones from the rice kernel. The machine was designed to be powered by a 2 hp electric motor. It was tested for its efficiencies in terms of stone and rice separation. The tray loss and impurity level after separation were also measured. The results showed that the machine has 69.0% and 87.7% stone and rice separation efficiency respectively. The tray loss and impurity level after separation were 12.8% and 8.1% respectively. The successful development of this machine is expected to solve problem of stone infestation usually associated with the locally produced rice.