The structural composition of a pneumatic control valve mainly includes two parts: the pneumatic actuator and the control valve (valve body). The following is a detailed summary of these two parts:
1、 Pneumatic actuator
The pneumatic actuator is the power source of the pneumatic control valve, responsible for converting the air pressure signal into mechanical motion, thereby driving the valve core action of the control valve. It mainly consists of the following components:
Cylinder:
The cylinder is the core component of a pneumatic actuator, with a piston or diaphragm inside, used to convert air pressure signals into linear motion.
Pistons or membranes:
In a piston actuator, the piston moves up and down inside the cylinder, and the linear motion is transmitted to the valve stem through the connecting rod.
In the thin film actuator, the thin film converts the air pressure signal into mechanical force, which drives the push rod to move.
Push rod:
The push rod connects the piston or diaphragm to the valve stem of the regulating valve, transmitting thrust to cause the valve core to move.
Spring (partial actuator):
Used to provide reset force, ensuring that the valve core can return to its initial position when the air pressure signal disappears.
enclosure:
Including locators, converters, solenoid valves, etc., used to control the input and output of air pressure signals, achieving precise adjustment.
2、 Regulating valve (valve body part)
The regulating valve is the control part of the pneumatic regulating valve, responsible for regulating the flow rate, pressure, temperature and other parameters of the fluid in the pipeline. It mainly consists of the following components:
Valve body:
The casing of valves is usually made of materials such as cast iron, carbon steel, stainless steel, etc., which have good strength and corrosion resistance.
Valve core:
Components that directly control fluid flow and pressure, common valve core structures include straight through, right angle, spherical, plunger shaped, etc. The valve core cooperates with the valve seat to adjust the flow rate by changing the gap size.
Valve seat:
Cooperate with the valve core to form a sealing surface, preventing fluid from passing through. The material and hardness of the valve seat need to match the valve core to ensure sealing performance and service life.
Valve stem:
Connect the valve core and the push rod of the pneumatic actuator to transmit thrust and make the valve core move. The valve stem needs to have sufficient strength and stiffness to withstand the thrust of the actuator and the impact force of the fluid.
Packing box:
Seal the gap between the valve stem and valve body to prevent medium leakage. Packing boxes are usually made of materials such as flexible graphite and polytetrafluoroethylene, which have good sealing performance and corrosion resistance.
Other components:
Including valve covers, bolts, nuts, and other connecting components, as well as auxiliary parts such as guides and seals that may be required.