Abstract:
Furnace is an enclosed apparatus in which heat is produced, either by burning a fuel such as coal, or natural gas, or by passing current through an electrical conductor.
The developed furnace with microcontroller based temperature control system consists of outer dimension of 60cm x 60cm x 75cm and inner dimension of 30cm x 18cm x 18 cm compartments. Nickel-chromium (80% nickel and 20%chromium) with ability to heat up the chamber up to 1280oC was coiled and used as a heating element. The inner section of the furnace was heavily lagged with refractory bricks to conserve the heat. Type K thermocouple was used to regulate and permits the temperature of the chamber to be fixed to desirable points. To improve the performance of the furnace, temperature controllers which consist of high temperature sensor, pre-amplifier, buffer amplifier, analog-digital converter, microcontroller and intelligent display was designed to monitor the temperature inside the chamber. The temperature controller was calibrated using standard temperature probes such as mastech meter to determine the accuracy and precision of the system. It shows that the furnace has perfect temperature control that monitors the temperature of the chamber and responds appropriately.
Testing was carried out to evaluate the performance of the furnace. From the results obtained, it was observed that the test was successful as the furnace heated up to 1082oC in less than 30mins with fast heating rate of 67oC/min and the efficiency of 70%, which is comparable to muffle furnaces purchased from abroad. The lower cost of design of the furnace coupled with its good heat retaining capacity, uniform heating rate, long estimated life time, safety and ease of maintenance. All these justify the usage. The furnace can be used for drying, ashing, melting and firing.
