Design, Fabrication and Testing of a Torsional Compression Thread-based Gari Screw-type Press (Cassava Pulp Mechanical Dewatering Machine)

Abstract

Gari is a popular type of food in Africa obtained from the dry frying of dewatered cassava pulp. Unfortunately, small scale Gari producers in Africa are hampered by adoption of inefficient and inappropriate pressing methods. This delays Gari production and results in low quality products. The purpose of this study is to design, fabricate, and test a torsional thread-based cassava pulp mechanical dewatering screw press which will provide a cheaper way of pressing cassava compared to the modern methods which are too expensive for the ordinary farmer due to the complexities involved in their processes and the components used in manufacturing them. The aim is to make a more hygienic system by enclosing the cassava pulp in a confined cylindrical space and providing a way of trapping the liquid emanating from the compressed cassava pulp during pressing. The screw will make it easy to drive and press the cassava pulp. The research also gives details of the manufacturing processes, tools, materials, that will be used if the product is fabricated. Cassava was not utilized in the testing process, rather, a wet napkin to test the pressing mechanism by reducing its moisture content. It was found that the machine could dewater 2 kg wet a napkin with 70 % to 15 % moisture in about 3 minutes. The maximum stress reported on the screw shaft handle was 2.773 ×107 N/m2 which was less than the yield strength of the material used for the simulation.