The operation principle of the pneumatic control valve in industrial automation is what?

Pneumatic control valve is used to adjust in the field of industrial automation process control medium flow rate, pressure, temperature, liquid level, etc. The process parameters. According to the control signal of the automation system, the automatic pneumatic control valve opening, so as to realize the medium flow rate, pressure, temperature and liquid level of the regulation. Pneumatic control valve is usually by electric actuators or pneumatic actuators and valve body two parts together. Straight travel mainly through single seater and direct two-seater type two kinds, the latter has a large flow capacity, unbalanced and the characteristics of stable operation, so often especially suitable for large flow, little pressure drop and leakage. Quarter-turn basically has: V electric regulating valves, electric butterfly valve, ventilation, pneumatic control valve, eccentric butterfly valve, etc. Flow capacity Cv value is one of the main parameters of pneumatic control valve selection, pneumatic control valve of the flow capacity is defined as: when the pneumatic control valve fully open valve pressure difference on both ends of 0. 1 mpa, the fluid density is 1 g/cm3, pneumatic - valve on the number of traffic flow diameter per hour, called flow capacity, also known as the flow coefficient, expressed as a Cv, unit for t/h, Cv value of the liquid press type calculation. According to the flow capacity Cv value look-up table size, you can determine the nominal size of the pneumatic control valve DN. In the automatic control of modern factory, pneumatic control valve plays a very important role, the production of the factory depends on the correct flow of the liquid and gas distribution and control. These controls both the exchange of energy, pressure reducing, or is a simple container loading, all need * some final control element to complete. The final control element can be thought of as the automatic control strength. In the regulator low energy level and high level necessary for the execution of flow fluid control function, the final control element to complete the necessary power amplification effect.