How to select the pneumatic valve from the use function?

1、 Installation space size. Pneumatic valve products are generally aimed at small and fine valve products, but there are also a certain number of customers with large valve caliber. There is a problem of selecting actuators here. Generally, for larger valve caliber, we use pneumatic actuators, while for smaller ball valves and butterfly valves.

2、 It is pressure and temperature resistant. This involves the selection of the nominal pressure and working temperature of the pneumatic valve. In terms of pressure resistance, if only the pressure is high, it is not difficult, mainly because the pressure difference will produce cavitation; in terms of temperature resistance, it is very easy to solve the problem below 450 ℃, and it is not difficult to solve the problem between 450 ℃ and 600 ℃, but when the temperature is above 600 ℃, the contradiction will be prominent; when the temperature is 80 ℃, it is generally not advisable to select soft sealing materials for the cut-off type control valve, and hard sealing cutting should be considered.

3、 It is a regulating function, which requires stable valve action; good performance of small opening regulation; regulating speed; selecting the required flow characteristics; meeting the adjustable ratio; small resistance and flow ratio (the ratio of rated flow parameter and nominal diameter of the valve).

4、 It's an explosion-proof star. It's the most appropriate to choose pneumatic actuator under the conditions of inflammable and explosive environment, and the nearby configuration must also be explosion-proof triple parts. Then what is the inflammable and explosive environment, such as, multi dust, multi coal ash, multi oil gas, flammable and explosive liquid, etc., which must be installed with pneumatic valve.

5、 It is the leakage and cut-off pressure difference. These are two inseparable and interrelated factors. The leakage shall meet the process requirements, and there are reliable protection measures for the sealing surface; the cut-off pressure difference (the pressure difference when the valve is closed) must be proposed (unfortunately, there is no such parameter in the calculation specification of many design institutes' regulating valves), so that the selected valve has enough output force to overcome it, otherwise, the actuator will be selected large or small.

6、 It's anti blocking. Even if it is a clean medium, there is also the problem of blocking. This is that the unclean things in the pipeline are brought into the valve by the medium, causing blocking. This is a common fault, so the anti blocking performance of the valve should be considered. Generally, the anti blocking performance of angle stroke type pneumatic valve is much better than that of straight stroke type, so the use of angle stroke type pneumatic valve will be more and more in the future.

7、 It is corrosion-resistant. It includes erosion resistance, cavitation resistance and corrosion resistance. It mainly involves the selection of materials and the service life of the valve, at the same time, it involves the economy. The essence of this problem is that the selected valve has better wear resistance and reasonable price. If you can choose all Teflon valve, you should not choose all corrosion-resistant all gold valve; if you can choose angle high-pressure valve with good anti cavitation effect and simple structure (meeting the service life of about two years), you should not choose other high-pressure valves with complex structure and high price.