What are the Main Accessories and Functions of Pneumatic Actuators？

 

The air powered actuator uses compressed air as a power source, converts the input control signal into a pneumatic signal and adds it to the pneumatic actuator to drive the valve. In order to achieve continuous adjustment or switching action, the air actuated control valve can be equipped with various accessories to achieve multiple control functions to meet the various special requirements of the control system for the pneumatic control valve. In other words, the accessories can make the function of the air actuator control valve more reasonable and complete.

 

Main Accessories of Pneumatic Actuator

 

1. Filter pressure reducing valve is an accessory in industrial automation instrument. Its main function is to filter and purify the compressed air from the air compressor and stabilize the pressure at the required value. Filter pressure reducing valves can be used for air supply and voltage stabilizing devices of various pneumatic instruments, solenoid valves, cylinders, spraying equipment and small pneumatic tools.

 

The filter is an air purification device used to filter out water and impurities in the air. It is also an indispensable part of the pneumatic actuator. If there is no filter, the pneumatic inhalation of impurities will affect its function and service life. The pressure reducing valve adjusts the pressure of the air source to achieve a stable pressure. After the pressure reducing valve adjusts the pressure properly, a locking device is applied. The function of the lubricator is to send the oil to the air pneumatic cylinder through the air pipe to achieve the purpose of lubricating the cylinder.

 

2. Solenoid valves generally realize the opening and closing of the valve by controlling the movement process of the pneumatic actuator. Solenoid valves are often used to switch valves, and control the on and off of air source and air circuit through voltage signals to control the opening and closing of valves. It can be divided into motorized solenoid valve and air actuated solenoid valve.

 

3. Limit switch, also known as travel switch, is an electrical switch used to indicate and feedback the movement limit position of mechanical equipment. Limit switches are divided into ordinary limit switches and explosion-proof limit switches. Materials include plastic limit switches, aluminum alloy limit switches, and stainless steel limit switches.

 

4. The valve positioner is the main accessory of the control valve. It uses the valve stem displacement signal as the input feedback measurement signal and the controller output signal as the setting signal for comparison. When there is a deviation between the two, the output signal to the actuator is changed to make the actuator act, and a one-to-one correspondence between the valve stem displacement times and the controller output signal is established. When the distance between the valve positioner and actuator is more than 60m, the positioner can overcome the transmission delay of the control signal and improve the valve action response speed.

 

5. In addition, one-way speed control valves, air control valves and quick exhaust valves are also necessary accessories.

 

6. Position retention valve is also called pneumatic lock valve, which is an auxiliary component of pneumatic unit combination instrument. When the gas source system fails, the position retaining valve can automatically cut off the passage between the regulating instrument and the regulating valve, so that the opening of the regulating valve can be stopped at the position before the failure, so that the process can run normally. After the air source failure is eliminated, it can automatically resume normal operation. Therefore, the guard valve can be used as a safety protection device in the automatic control loop.