Pnematic control valve working condition and how to choose pneumatic control valve

After determining the output force of the actuator, select the corresponding actuator for the control valve according to the requirements of the use environment.Pneumatic control valve should be used when there are explosion-proof requirements on site.Considering from the aspect of energy saving, electric control valve should be selected as far as possible.If the adjustment precision is high, can choose the hydraulic actuator.Such as power plant transparent machine speed regulation, oil refinery catalytic unit reactor temperature regulation control.
 
The action mode of the control valve is only in the choice of pneumatic actuator, its action mode through the combination of positive and negative action of the actuator and valve formed.Combination form has 4 kinds namely positive (air off type), positive and negative (air open type), inverse (air open type), anti (air off type), through these four kinds of combination of the formation of the regulating valve action mode has two kinds of air open and air close.For the choice of control valve action mode, the following three aspects are taken into consideration:
a) process production safety;
b) characteristics of the medium;
c) ensure product quality and minimize economic losses. 
 
On the function can replace many functions are not complete products, pneumatic control valve to simplify the modeling, to solve the factory management complex, complex model selection, maintenance workload.The adjustable ratio of the electric control valve is large, generally up to 100, and from the opening of 10% to 90% can ensure good regulation.Good ability to overcome pressure difference, anti-blocking function, the flow path is the simplest, open adjustment, KV value is the largest, the best self-cleaning performance.The flow characteristic of the electric regulating valve is approximately the same percentage.And the actual work of the flow characteristics, because there is always before the valve, valve after the pressure difference, the actual curve of the traditional control valve will be very big distortion is also relatively small, so it not only has good regulation performance, but also has good economy and energy saving. 
 
Compared with pneumatic control valve, electric control valve with the power supply is both convenient and saving, eliminating the establishment of a series of trouble gas source station.According to the actual use of the environment, the lined teflon ceramic ball valve or the whole lined ceramic hard sealed ball valve, in order to obtain higher corrosion resistance and wear resistance.Extruded high strength aluminum cylinder block, the inner surface by fine grinding and hard anodizing treatment, long service life, low friction coefficient, quick action. 
 
As can be seen from the above pneumatic control valve: the basic error and sensitivity of the electric control valve is up to 0.3%, it is not necessary to establish air source in addition, it is not suitable for the occasions where the explosion-proof requirements are too high.And the basic error and sensitivity of pneumatic control valve reach 0.5%, but it is essentially safe.Pneumatic control valve is suitable for the occasions with high explosion-proof requirements.