Research On The Control Of Temperature And Temperature Uniformity For Large Vacuum Annealing Furnace

Vacuum annealing furnace is a kind of heating equipment that is widely used in vacuum heat treatment, and its temperature-dynamic characteristics influence on the product quality directly. In this research, we designed the controlling system for vacuum annealing furnace of large-scale pipe, focusing on the control of temperature and temperature uniformity.Vacuum annealing furnace for rare metal tubes has the characteristics of high capacity of furnace chamber, variety of temperature zone for heating, strong interference as well as great differences of temperature uniformity in each zone, and high accuracy of temperature-control. In this research, the control strategy for the temperature and temperature uniformity of vacuum annealing furnace, based on the productive facility and main technical parameters, is used to study the temperature-related problems of the vacuum annealing furnace. In controlling strategy, the variable parameter self-tuning fuzzy PID control strategy is used to realize the online optimization of PID parameter. What’s more, local adjustment for each temperature zone can be realized by OPC technology. All those lead to the aims of automatic control for entire vacuum process, high precision of temperature control and good temperature-unity in multi-zone. The first-order plus dead-time temperature-controlling mathematical model has been built in this experiment for model identification. Industrial Personal Computer (IPC) is used as the upper computer, both programmable controller PLC and programmable temperature-controlled instrument is used as the lower computer, based on multibus architecture, IPC+PLC+intelligent instrument based temperature controling system is finished. KingVIEW6.53configurative software is used to design the human-computer interface and collect data about temperature and its controlling parameter for the upper system, aiming for the record, display, alarm feedback and online operations in upper pictures. The system design meets the requirements of high accuracy of temperature-control in vacuum annealing furnace, and realizes temperature uniformity in multi-zone. It has advantages in ensuring product quality and reducing energy consumption, which bring great economic and social benefits.