Study of High-temperature Three-zone Furnace and Realization of Uniform Temperature Field

Abstract

In this paper, a unique design using alumina insulation discs with the Carbolite tube furnace was proposed to enhance the temperature uniformity and reduce the heat loss when the furnace temperature is above 1000 °C. The assessment of the high temperature furnace characteristics including axial temperature distribution, radial temperature distribution, furnace loading effect and furnace reproducibility study, was conducted by using 2 pieces of Type B thermocouples after examining their in homogeneity and calibration results. The results showed that the heat loss of the furnace can be minimized and a practical realization of the temperature uniformity in both axial and radial directions can be achieved based on the different measurement requirements. In this study, it indicates that the minimum furnace non-uniformity is 0.9 °C in the temperature range 1000 • 1200 °C when immersion depth of the thermocouples are fixed at 550 mm, and the maximum furnace non-uniformity is 4.0 °C in the temperature range 1200 • 1300 °C at 200 mm zone (400 • 600 mm). Therefore, the minimum length requirement for the thermocouple using this furnace is 580 mm in future calibrations and best axial uniformity can be achieved when the thermocouple length is longer than 730 mm.