Abstract:
The development of indigenous furnace technology is vital to the Nigerian engineering industry. Existing efforts have developed hydrocarbon fuel fired types such as crucible and rotary furnaces, but with concomitant problems of operational difficulties, environmental pollution, poor product qualities, and temperature control. Fortunately, these problems are usually absent in electric type furnaces. Therefore, there is the need for the development of electric furnaces. This is the thrust for this work: Development of a laboratory bench top electric heating furnace designed to generate heat by ohmic heating, and achieve a temperature of l200°C in one hour (on 220V ac), with electronic temperature monitoring and control. Towards constructing the design, the required electrical components, construction steel sheet and bars were sourced from the local technical market. The refractory raw materials requirements of the design were sourced from two local deposits- lgbokoda beach silica sand and Ijapo Kaolinitic clay deposits, both in Ondo state. Process routes for using these local deposits to produce the refractories were determined by varying pretreatments, particle sizes, compositions and moulding methods for different samples to obtain the combination which will give the best of desired properties in the products. The prototype was constructed with least design modifications. The resulting furnace was tested for performance evaluation. Although firing could not be continued to exactly 1200°C due to insufficient insulation bricks, a promising heat build up average rate of 20°C per minute was obtained. Also, the control system served for switching on/off the furnace at various set temperatures. The developed furnace has the advantages of ease of operation and control, environmental friendliness, and low cost of operation over the hydrocarbon fuel fired ones.
