Design and construction of walk-in hot air cabinet dryer for the food industry

Abstract

The need for an efficient dryer which is within the reach of all categories of food processors has resulted in the design, construction and testing of a 140-tray "walk-in" hot air cabinet dryer. It is an improvement of a dryer made by Rolls Royce Industrial Ovens Ltd of England. The number of trays were increased by 40 per cent to give a loading area capacity of 86.8 m2 with corresponding increases in air circulation and heat requirement by 17 per cent respectively. Temperature distribution tests conducted at five positions within the dryer recorded highest deviations of +2.8 °C from the set temperature at 60°C during the transient period and 1.1 °C when the temperature settled after 13 min. Further tests conducted with fermented cassava dough established a drying capacity of 3.9 kg of the dried product/m2 and an overall drying rate of 0.32 kg/l\O/h m2. The total cost of construction amounted to $10,000.00 which is 20 per cent the cost of the one from Rolls Royce industrial Ovens Ltd of England and hence its affordability. The dryer has since been exported and installed at Pouma, Cameroon