Pneumatic actuators are a kind of classification in actuators. From the perspective of technical performance, the advantages of pneumatic actuators mainly include the following four aspects:
(1) Quick action and quick reaction.
(2) Motor is easily damaged when stroke is blocked or the valve stem is stuck.
(3) The large load can adapt to the application of high torque output. However, the current electric actuators have gradually reached the current aerodynamic load level.
(4) Good adaptability to working environment, especially in flammable, dusty, explosive, strong magnetic, radiation and vibration and other bad working environment, better than hydraulic, electronic, electrical control.
Due to the special use environment of pneumatic actuators, the probability of failure in operation is greatly increase, among which vibration is one kind. Vibration of control valve of pneumatic actuators will cause the control system to fail to work normally, and the main reasons for vibration are as follows:
1. External vibration source, that is, the equipment pipe itself has vibration.
2. Vibration caused by fluid erosion.
3, pneumatic actuator control valve selection does not meet the requirements of selection. Such as flow characteristics do not fit, valve diameter is large, poor spring stiffness and so on, causing the control valve vibration.
If it is found that the vibration is inherent in the equipment pipe. The equipment pipe can clean and adjust again to make the vibration disappear.
If it is the problem of pneumatic actuator control valve itself, the restrictor orifice can use to absorb part of pressure drop, reduce throttling speed and overcome valve vibration. Moreover, the restrictor orifice can also change the natural frequency of the system to avoid vibration caused by the natural frequency of the control valve being close to the natural frequency of the system.