The Design And Implementation Of The Testing System Of The Large Flow Waterway Valve

At present, we have researched and development a few valve testing systems. Unfortunately,most of their working medium was hydraulic oil, and their flow is very small. This paper, we takethe industrial control computer and PLC as the core of the control system. Then, we build a completepressure and water control system for the testing of large flow waterway valves. By the testingsystem, we can gain the experimental data of newly developed valve. Than we can gain theperformance parameters of the valve and carry out further development work on the valve byanalyzing the experimental data. The result of this experiment proves the testing system to bepractical. The work this paper finished is as follows.First, according to the water valve test requirements, a set of air-water mixture pressure pipelineneed to be designed. Through the calculation, determine the initial parameters of the system. At thesame time, proposed the strategy of the pressure controlling of the gas-liquid hybrid. The pipelinesystem comprises two20m3large pressure cylinders, four gas flow regulating valve, two centrifugalpumps, one piston pump and a high-pressure gas source. When the valve is testing, four gas flowregulating valve are respectively using to control the intake and exhaust of two20m3large pressurecylinders. In the provision of enough water the large flow water valve testing required, the precisecontrol of the pressure difference between the ends of the tested valve is needed, so as to meet thetest requirements.Second, the AMESim model of the designed the water-air mixing pressure system isconstructed. After the simulation calculation of the system is done, we can ensure that the system iseffective and system parameters are right. In the simulation of the water-air mixing pressure system,it is hard to select model for air-water interface. This paper, we take two plunger cylinders as themodel of the chamber, and take the piston whose mass is zero as model of the air-water interface.Third, In order to solve the lag problem of the practical use of the aerodynamic flow regulatingvalve, this paper adopts Knocker hysteresis compensation method, controls flow regulating valvetaking advance action in the direction of needing move. Thereby we can remove the lag of thepneumatic flow regulating valve, improve the accuracy of pressure control and eliminate the systemshock. At the same time, according to the system permissible error, a threshold is set to reduce thenegative effect brought by the Knocker hysteresis compensation method which brings the fastfrequency of the valve action. When the error of the pressure difference between the ends of thetested valve across threshold, the Knocker hysteresis compensation will be canceled to reduceaerodynamic flow regulating valve wear.Last, we finish a set of control subsystem of the valve testing system including the controlprogram of Siemens PLC and the control-display program of the industrial computer. Complete the system debugging. The experimental results validate the effectiveness of the proposed designedmethod and controlling strategy.