Views: 5 Author: Site Editor Publish Time: 2021-12-20 Origin: Site
Now we introduce the different classifications of pneumatic control valves and valve positioners!
Pneumatic control valve
Pneumatic control valve can be divided into linear stroke and angular stroke according to the valve action mode; divided into pneumatic and electrical according to the signal form; divided into single-acting and double-acting according to the principle of valve actuator; in addition, according to the working principle of the positioner itself, it can also be divided into multiple Various forms, specifications, models, etc.
Pneumatic control valve uses compressed gas as power source, cylinder as actuator, and uses valve positioner, converter, solenoid valve, retainer valve, gas tank, gas filter and other accessories to drive the valve to achieve the switch value. Or proportional adjustment, receiving the control signal of the industrial automation control system to complete the adjustment of the pipeline medium: flow, pressure, temperature, liquid level and other process parameters.
The valve positioner is the main accessory of the regulating valve. It receives the output signal of the regulator, and then uses its output signal to control the pneumatic control valve. When the regulating valve is working, the displacement of the valve stem is fed back to the valve positioner through a mechanical device, and the valve position status can be transmitted to the upper system through electrical signals.
The valve positioner can be divided into linear stroke and angular stroke according to the valve action mode; according to the signal form, it can be divided into pneumatic and electrical; according to the principle of valve actuator, it can be divided into single-acting and double-acting; in addition, according to the working principle of the positioner itself, it can also be divided into multiple Various forms, specifications, models, etc.
The correct installation of the valve positioner and the actuator directly affects the use effect of the valve positioner. A reasonable installation is to reasonably connect the valve positioner fixed on the mounting plate and the valve positioner installation accessories connected to the actuator into a reasonable way. One. Today we will introduce how to install the valve positioner!
1. First, fix the valve positioner and the mounting plate together. The method is to open the upper case of the valve positioner, and use three M5*20 screws to pass through the three holes in the shell to connect with the mounting plate.
2. Connect the feedback part of the valve positioner to the actuator, loosen the valve stem nut on the regulating valve, and insert the support plate in the feedback part between the indicator and the connecting nut to tighten.
3. Fix the mounting plate with the valve positioner and the actuator bracket with M10*15 screws in the two screw holes according to the required position.
4. Insert the connecting pin on the feedback connecting plate of the feedback component into the opening groove of the valve positioner cam feedback stem.
5. Different types of actuators should ensure that when the valve position is 50%, the cam feedback lever should be in the horizontal position.
6. After adjusting all parts of the installation and connection, fix and lock it.