Development of a twin screw extruder

The aim of this study was to design, construct a multi-purpose twin screw extruder and evaluate its performance. All parts of the extruder were constructed using locally available materials and was made suitable for both batch and continuous production. The extruder essentially consists of the hopper, barrel, variable screw speed and temperature control, electrical motor and replaceable dies to give different sizes and shapes in the final products. It could also handle feed materials of different rheology. Performance evaluation of the extruder was done using cocoyam flour, varying feed moisture content (FMC) and screw speed (SS). Both the FMC and SS were observed to significantly affect all performance indicators (expansion ratio, residence time, throughput and functional efficiency) of the extrusion process. The availability and efficient access to this equipment would encourage the development of locally made extruded products. Through effective utilization, it is expected that the extruder would expand the production and processing of extruded foods.