Temperature Uniformity Control In a Gas Heated Box Furnace

Industrial heat treatment furnaces are used to create desirable material properties in metals. Such furnaces are qualified for certain interior volumes and temperature ranges to ensure all material meets the required specifications. These qualifications are established and maintained by a Temperature Uniformity Survey (TUS). This paper investigates the temperature uniformity of a gas powered industrial box furnace, establishes a mathematical model of the furnace in the form of a reduced-order transfer function (TF), and tests the impact of control system changes in terms of temperature rise time and steady state error. The goal is to determine if a better configuration of installed hardware exists. This study shows that fine adjustments to the Proportional, Integral, Derivative (PID) controller yield measurable reductions in rise time while maintaining compliance with the TUS standard.