The control valve is a control element widely used in the industrial field. It can control the flow, pressure, temperature and other parameters of the medium in the pipeline, so as to realize the precise control of the industrial process. Hongguang instrument introduces the types, structures, working principles and applications of control valves in detail.
1. Types of control valves
According to the structural form and control mode of the control valve, the control valve can be divided into the following categories:
（1）Globe valve: used to cut off the flow of medium in the pipeline, mainly suitable for low-speed flow and high pressure difference occasions.
（2）Regulating valve: used to adjust the flow and pressure of the medium in the pipeline, mainly suitable for medium and low speed flow and medium and low pressure difference occasions.
（3）Safety valve: used to protect the safety of pipelines and equipment. When the pressure of the medium in the pipeline exceeds the set value, the safety valve will automatically open to discharge the excess medium.
（4）Pressure reducing valve: used to reduce the high-pressure medium in the pipeline to the required low-pressure level to ensure the normal operation of the pipeline and equipment.
（5）Check valve: used to prevent the medium from flowing back and protect the safety of pipelines and equipment.
（6）Solenoid valve: It is used to control the switch, direction, flow, pressure and other parameters of the fluid, and is widely used in automatic control systems.
2. Second, the structure of the control valve
The structure of the control valve is mainly composed of valve body, valve cover, valve seat, valve core, actuator, seal and other parts. Among them, the valve body and bonnet are generally cast or forged parts, and the valve seat and valve core are made parts. Actuating agencies include manual, electric, pneumatic, hydraulic and other types, which are used to control the opening and closing and adjustment of valves.
3. The working principle of the control valve
The working principle of the control valve is based on the principles of fluid mechanics and control theory. When the actuator acts on the valve core, the gap between the valve core and the valve seat will change, thereby controlling the flow and pressure of the medium. The exact working principle depends on the different types of valves.
For example, for the stop valve, when the actuator acts on the valve core, the valve core will move to the valve seat, so that the sealing surface on the valve seat and the sealing surface on the valve core fit together, thus cutting off the flow of the medium in the pipeline. As for the regulating valve, the flow and pressure of the medium are controlled by changing the gap between the valve core and the valve seat.
4. Fourth, the application of the control valve
Control valves are widely used in petroleum, chemical industry, electric power, metallurgy, light industry, medicine, environmental protection and other industrial fields. They are often used to control the flow, pressure, temperature and other parameters of the medium in the pipeline, so as to ensure the safe, stable and efficient operation of the industrial process.
For example, in the oil refining industry, control valves can control the flow and pressure of crude oil, oil products, gases and other media to ensure the stability and quality of the refining process; in the chemical industry, control valves can control the flow and pressure of various chemicals , to ensure the accuracy and safety of chemical reactions.
As an important industrial control component, control valve is of great significance to ensure the safe, stable and efficient operation of industrial production.