Research And Application Of Annealing Process Control System Of Bell Furnace

In this paper, the author has researched annealing process control system of Tongling Jinvi Copper Bell Furnace based on many years of application experience. The paper reveals all kinds of process control law and control principles to the batch annealing process. For the feature that the main process parameter- temperature requires a higher control quality, the author analysises its control method and control algorithm.As bell furnace heating process is a multi-volume, delay, non-linear process, the temperature change mechanism is very complex and difficult to use mathematical reasoning method to establish the mathematical model of the controlled process. Thus the temperature step response experimentation is done, the time constant, dead time, and magnification factor of the controlled process are obtained. The approximate mathematical model is then established. The PID control law is selected based on the object characteristics. Because gas burner combustion depend on the combustion media flow, the "burner misfire" phenomenon occurs and a high accuracy temperature control cannot be obtained when the PID control signal is very small. So an intelligent fuzzy controller is applied to control burner. From the real-time control results we can see that the fuzzy controller improves the temperature control accuracy from±5℃up to±1℃.Except temperature control, the batch annealing process also includes pressure, protective atmosphere and other control objects. So a multi-level system composed of instruments, PLC and computer is designed to control the batch annealing process. The paper describes the batch annealing process control system on two aspects:hardware selection and software design.Many years of operation practice proves that the batch annealing process control system of bell furnace shown in this paper is safe and reliable, and control system performance achieves the expected requirement.