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Adjustable ratio description of pneumatic control valve


Release time:

2021-07-24

In the process of automatic control,Pneumatic control valveQuality failure will cause the automatic control process to lose high-quality conditioning, poor flow characteristics will affect the quality of regulation, large leakage and unreliable action will cause the regulation to fail, which will cause great loss in the production process and increase labor intensity. Therefore, the selection and use of pneumatic control valve has been paid more and more attention.

Adjustable ratio description of pneumatic control valve

In the process of automatic control,Pneumatic control valveQuality failure will cause the automatic control process to lose high-quality conditioning, poor flow characteristics will affect the quality of regulation, large leakage and unreliable action will cause the regulation to fail, which will cause great loss in the production process and increase labor intensity. Therefore, the selection and use of pneumatic control valve has been paid more and more attention.
The accuracy of the control of the pneumatic control valve can be changed through the performance of the energy and flow of the logistics. Regulating valve control energy can be used to determine the adjustable ratio, adjustable ratio refers to the control valve on both sides of the differential pressure for a fixed value, the control valve can control the ratio of large flow and small flow. When the control valve is used in series pipelines, the adjustable ratio is proportional to the square root of the pressure drop ratio; when used in parallel pipelines, the greater the bypass flow, the lower the adjustable ratio, and the smaller the control ability. When there are 2 or more than 2 control valves are operated in parallel and at the same time, it is necessary to pay attention to the degree of bypass. In actual production, in addition to the control valve, there are other pipelines, so the pressure difference before and after the control valve will change, which is called the operation flow characteristic. There are linear valves, equal percentage valves and parabolic valves in detail. Among them, the use of equal percentage valves is more extensive and adaptable.
The selection of pneumatic control valve needs to be based on the characteristics of the medium, control requirements, installation environment, etc. combined with their own flow characteristics and structure for reasonable selection. In addition to these considerations, you also need to consider the way the bonnet and the choice of packing.
Pneumatic control valve daily maintenance of the main content should be the following:
1. Inner wall of valve body. Check its pressure resistance and corrosion resistance.
2. Valve seat. Due to the infiltration of the medium, the inner surface of the thread used to fix the valve seat is susceptible to corrosion and the valve seat is loose, so attention should be paid to it when viewing. For high-pressure occasions, you should also check whether the valve seat sealing surface is damaged.
3. Spool. To carefully check whether the various parts of the spool is corroded and worn, especially in the case of high pressure difference, the spool wear is more serious, should pay attention. In addition, it should also be checked whether the valve stem has a similar phenomenon, or the connection with the valve core is loose, etc.