Pneumatic Valve Actuator

Operating Conditions:

1. Operating Media

Dry or lubricated air, or the non- corrosive gases,The maximum particle dia meter must less than 30 μm.

2. Air Supply Pressure

The minimum supply pressure is 2 Bar. The maximum supply pressure is 8 Bar.

3. Operation Temperature

Standard:-20℃~+80℃, Low-temperature Type:-40℃~+80℃, High-temperature Type:-20℃~+160℃

4. Travel Adjustment: Have adjustment range of ±5° for the rotation at 0° and 90°

5. Application: Either indoor or outdoor

Pneumatic actuators are actuators that use air pressure to drive open and close or adjust valves. They are also called pneumatic actuators or pneumatic devices, but they are generally called pneumatic heads. Pneumatic actuators are sometimes equipped with certain auxiliary devices. Commonly used are valve positioners and handwheel mechanisms. The function of the valve positioner is to use the feedback principle to improve the performance of the actuator, so that the actuator can realize accurate positioning according to the control signal of the controller. The function of the handwheel mechanism is to use it to directly control the control valve to maintain the normal production when the control system is out of power, gas, no output from the controller or failure of the actuator.

Working principle

When compressed air enters the pneumatic actuator from the A nozzle, the gas pushes the double piston to move linearly to both ends (cylinder head end). The rack on the piston drives the gear on the rotating shaft to rotate 90 degrees counterclockwise, and the valve is opened. . At this time, the gas at both ends of the pneumatic actuator valve is discharged with the B nozzle. Conversely, when compressed air enters the two ends of the pneumatic actuator from the B Guanzui, the gas pushes the double plug to move linearly in the middle, and the rack on the piston drives the gear on the rotating shaft to rotate 90 degrees clockwise, and the valve is closed. At this time, the gas in the middle of the pneumatic actuator is discharged with the A nozzle. The above is the standard transmission principle. According to user needs, the pneumatic actuator can be installed with the transmission principle opposite to the standard type, that is, the clockwise rotation of the collimated shaft is selected to open the valve, and the counterclockwise rotation is to close the valve. Single-acting (spring return type) pneumatic actuator A nozzle is the air inlet, B nozzle is the exhaust hole (the B nozzle should be installed with a muffler). The inlet of nozzle A is to open the valve, and the valve is closed by spring force when the air is cut off.

The type and structure of the adjustment mechanism of pneumatic actuators are roughly the same, mainly because the actuators are different. Therefore, in the introduction of pneumatic actuators, it is divided into two parts: the actuator and the regulating valve. Pneumatic actuator is composed of two parts: the actuator and the regulating valve (regulating mechanism). According to the magnitude of the control signal, a corresponding thrust is generated to push the regulating valve to act. The regulating valve is the regulating part of the pneumatic actuator. Under the action of the thrust of the actuator, the regulating valve produces a certain displacement or angle to directly regulate the flow of the fluid.

Basic composition

1. The pneumatic device is mainly composed of cylinders, pistons, gear shafts, end covers, seals, screws, etc.; the complete set of pneumatic devices should also include opening instructions, stroke limits, solenoid valves, positioners, pneumatic components, manual mechanisms, and signals Feedback and other components.

2. The connection size of the pneumatic device and the valve should meet the requirements of ISO5211 (bottom), GB/T12222 and GB/T12223.

3. The pneumatic device with manual mechanism should be able to use its manual mechanism to open and close the pneumatic ball valve when the air source is interrupted. When facing the hand wheel, the hand wheel or handle should rotate counterclockwise to open the valve, and rotate clockwise to open and close. The valve is closed.

4. When the end of the piston rod is internally or externally threaded, there should be a wrench mouth suitable for standard wrenches.

5. The sealing ring of the piston should be easy to replace and repair.

6. For pneumatic devices with buffer mechanism, the stroke length of the buffer mechanism can refer to the regulations in "Table 1".

7. The pneumatic device with adjustable buffer mechanism should have a mechanism for adjusting the buffer function outside the cylinder.

8. The thread size of the air inlet and outlet of the cylinder should comply with MANUR NORM (accessory standard) sypv, GB/T7306.1, GB/T7306.2 and GB/T7307.