The advantages of pneumatic actuators and their common three types
Pneumatic actuator has the advantage that, even if the leak will not pollute the environment, its work environment adaptability is good, not inflammable, explosive, strong magnetic, strong radiation, etc. The influence of the bad environment, can be in power, oil source, signal will be reset to the default security valve position, protect the valve system, because of the air compressor, pneumatic movement stability is a bit poor.
According to its working principle, the pneumatic actuator can be divided into three types: ordinary type, fast closing type and regulating type
ordinary
Air source treatment triplet elements (including filters, pressure relief valves and oil mist) and solenoid valves are a basic form. When the valve needs to be opened, the solenoid valve enters the actuator A chamber through the solenoid valve (the gas in the actuator B chamber is discharged into the atmosphere through the solenoid valve), pushing the left side of the piston, and the valve is opened. When the valve needs to be closed, the solenoid valve loses power, the pressure gas enters the B chamber of the actuator through the solenoid valve (the gas of the actuator A chamber is discharged into the atmosphere through the solenoid valve), and pushes the piston to the right to close the valve. When the actuator is a single function, the solenoid valve to select two - way type. When the actuator is dual function, the solenoid valve chooses two five-way type, when the valve is out of power to preserve position, the solenoid valve chooses three five-way type when the gas.
A fast shut
Single-acting actuators are commonly used for rapid valve closing. Fast opening pneumatic actuator is based on the ordinary pneumatic actuator to increase the fast exhaust valve, quickly discharge the gas in A cavity, and speed up the closure of the actuator. When the valve needs to be opened, the solenoid valve is charged, and the gas enters the A chamber of the actuator through the solenoid valve and the quick exhaust valve. The compression spring pushes the left side of the piston and the valve opens. When the valve needs to be closed, the solenoid valve loses power, the gas is cut off, A under the pressure of the spring, the gas in the chamber is quickly discharged through the rapid exhaust valve, and the piston right row valve is quickly closed.
External regulation
Pneumatic actuators can receive current, voltage or airflow signals from the system (among which current signals are more common). The opening of the valve can be adjusted according to the size of the signal. The opening of the valve can be fed back to the system in the form of signals according to the requirements of users, forming a closed-loop control. The electric positioner or air positioner actuator is used to replace the solenoid valve in the ordinary pneumatic actuator to form the regulating pneumatic actuator. The default values of the locators are different for different manufacturers. You need to adjust them based on user requirements.
