| About 70% of China’s 1.3 billion people use groundwater as drinking water, but90% of the nation’s urban groundwater has been polluted, which is pointed out in the China Sewage Treatment Industry Indepth Research and Investment Strategy Report,2013-2017.And the air flotation water purification technology has a good development prospect in the field of water treatment,the equipment is simple with fast separation and without secondary pollution.The paper fully expounded the present situation both at home and abroad and the problems existing in the development of air flotation water purification,the control system on rotary spray pressurized dissolved air flotation water purification was designed on the basis of rotary spray pressurized jet grouting pressurized,who includes rotary spray pump outlet pressure control system, secondary jet inlet gas pressure control system and cloth device inlet pressure control system.The dissolved air system adopted since the stable air dissolving tank instead of the traditional tank, using MATHCAD and FLUENT software to analysis the performance of jet pump and high pressure jet machine. For dissolving tank, secondary jet device, as well as gas device’s working principle is analyzed, according to Henry’s law to determine when the system was dissolved air rate is highest when the control Parameters.The control system was developed based on the technology of PLC and frequency converter, The selection was completed for PLC, inverter, pressure transmitter,regulating valve, level gauge in meeting to the needs of the industrial construction site and striving to maximum cost performance. Using SIMATIC instruction set, selecting statement list(STL) programming language to program, realizes the constant pressure control of the controlled object, through the system control process design, the points distribution and module configuration, and connection design module, using the force control configuration software to complete the control system of the monitoring to implement the testing process automation and improved the control precision and work efficiency.Control system mathematical model is established, using the SIMULINK of MATLAB to simulate control system, this article analyzes the characteristics of the output features of the system who is open loop,and then discusses the proportional,integral, differential control effect on the steady-state performance and dynamic performance when the system is closed loop. Then we can know that we can get a satisfactory response to the results of PID Parameters when it takes smaller proportion coefficient and the differential time constant value, through setting up suitable integral time constant in the system. |
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