DEVELOPMENT AND EVALUATION OF A FLOATING FISH FEED PRECONDITIONING SYSTEM

Abstract

The preconditioners heats, hydrates and mixes the dry raw materials before extrusion and automatically doses the pre-treated product into the extruder. FUTA has developed a floating fish feed extruder, however there is no locally available preconditioning system that could enhance the floatability of the fish feed. Therefore a fish feed preconditioner was designed, fabricated and tested to improve the quality and floatability of the feeds. The machine consists of two insulated cylindrical barrel, paddles configuration on a shaft, frame, hotwater and feed mash inlet, discharge chute, chain and sprocket. Various components of the preconditioner were designed using standard engineering formulae. The preconditionerthroughput capacity is 650 kg/hr. It is poweredbya three-phase 11KW electric motor which transmits power to the machines shaft and paddle configuration via chain and sprocket. The effects of particle size and paddle rotating speed on mixing efficiency, final moisture content and temperature of the preconditioned feed was evaluated. The machine was evaluated using NIOMR feed formulation at feed mash particle sizes of 900 μm, 550 μm, 520 μm and paired paddle rotating speed of the lower and upper chamber at (96.8; 145.2), (122.6; 183.2) and(174.5; 260.8) rpm respectively.Hot water and feed mash were introduced into the preconditioner simultaneously at rate of 2 litres per 13kg batch.The analysed results obtained from the evaluation shows that at paired paddle speeds of (96.8; 145.2) rpm all the particulate absorbed more moisture and temperature. There was a significant increase in temperature and moisture content level of particles size 550 μm and 520 μmat all paired paddle rotating speed.The uniformity of mix (mixing efficiency) at the lowest paired paddle speed was the best with its Biot number averaging 0.1. The study suggests that appropriate combination of the processing parameters will improve heating and hydration of feed particles in the machine. The machine is recommended for use in feed production.