Optimization Of The Level Of The Pneumatic Control System Of Horizontal Continuous Casting Brass Holding Furnace

In the continuous casting of copper pipe,to extend the casting time and to improve the utilization of residual liquid,insulation furnace will be divided into three chambers by the German engineers,respectively,the feed chamber,pressure chamber and casting chamber.The bottom of the three chambers is connected to each other,the pressure chamber through the high pressure nitrogen,by controlling the size of the pressure to adjust the liquid level of the remaining two chambers.But the system insulation furnace level has a great fluctuation,it not only will lead to copper liquid temperature changes,insulation layer of graphite scales and impurities involved in copper liquid,seriously affecting the quality of copper,but also increase the risk of the copper liquid overflow and leakage.Therefore,the precise control of the level of the holding furnace is the key factor to ensure the safety of the copper continuous casting system,improve the quality of the brass and the utilization rate of the residual liquid.However,due to the time-varying and non-linearity of the pneumatic control system of the holding furnace level,and there are many uncertain disturbance factors,the accurate mathematical model can not be established.The conventional control can not meet the control requirements,so mew Control methods and control strategies must be taken.In this paper,based on the hydraulic control system of the heat preservation furnace of a copper tube factory,which is Transformed by Zhang Yuanshen,put forward the structure and control strategy optimization program.The sensor,which can only detect the lower limit of the pressure chamber level,liquid level and liquid level limit,will be replaced by the whole bridge circuit can be used to continuously detect the liquid level of the casting cavity laying the foundation for the follow-up precision control;Proportional pressure reducing valve instead of the original system of gas control valve to control the intake air volume,the use of proportional valve and the ball valve with a drive instead of the original system of electric control two way ball valve to control the displacement.From the theory and simulation of two aspects of its optimal analysis,so that it can achieve good control effect,thereby enhancing the system safety and brass quality.Using the AMESim simulation software,the model of the gas control system of the holding furnace is set up.The simulation results of the normal operation and the injection of copper liquid in the feed chamber are carried out to find the worst situation of the working environment of the system,and provide the controller for the next step data support.The PID control strategy is added to the system.Firstly,the mathematical model of the gas control system and the nitrogen chamber of the heating chamber are deduced.The block diagram of the system is established.Using the ZN scale method,the ratio,integral and differential coefficients of the PID controller are determined and simulated.The simulation results show that after the PID controller is added,the control effect of the gas control system is very good,which basically meets the control requirements during normal operation,layingthe foundation for the next step in designing the ideal signal of the casting chamber level change.Casting chamber level changes in the ideal signal design: As the detection system can only detect the pressure of the pressure chamber and casting chamber level changes,by the third and fourth chapter of the simulation results,we can found that the pressure of the pressure chamber is Increase and then decrease,and the pressure curve has a lot of ups and downs,so the use of pressure chamber pressure and pressure rate of change to determine the feeding time point,will cause a logical error,so that simulation can not be carried out.In this paper,the change of the liquid level of the pressurized chamber and the deviation of the ideal change amount are used to determine the time of feeding.The pressure chamber is used to determine the time of copper liquid depletion in the pressurized chamber.Ideal signal is added to the AMESim model for simulation,the results show that liquid level of casting cavity has a greater volatility after injecting copper liquid.Conventional PID controller is difficult to eliminate the fluctuation of liquid level when the injection of copper.In this paper,fuzzy self-tuning PID controller is designed by MATLAB,and AMESim is connected with MATLAB by using joint simulation technique.Using the controller in MATLAB to control the AMESim model and simulate it,it can be seen from the simulation results that the dynamic performance of the system is greatly improved when there is copper injection.