The principle of electric actuators, the working principle of electric actuators
Electric valve actuator = electric actuator + valve body
There are many types of valve bodies: straight-through valves, electric butterfly valves, ball valves, gate valves, etc.
Electric actuators + various valve bodies form another type of product - electric control valve (can also be subdivided into: electric adjustable straight-through valve, electric modulating butterfly valve, electric control valve, etc.).
Therefore, it is customary for an electric actuator to be an electric actuator without a valve body.
The electric actuator is composed of an electric motor, a speed reduction mechanism, a limit mechanism, an over-torque protection mechanism and a position feedback device.
The electric actuator uses a motor as a driving source and a DC current as a control and feedback signal.
When the upper meter or the computer sends out the control signal, the electric actuator moves in proportion to the signal size, and the valve or the damper is opened to the corresponding opening degree through the output shaft, and the system opening degree signal is fed back to the control room, thereby completing the system. Adjustment function.
Electric actuators can also be used with instruments such as operators and servo amplifiers.
The role of the operator is:
A. Pass the signal to provide the operator with visual input and feedback signal values in the control room for easy observation of the on-site valve position.
B. When the control signal fails or repairs the system, it can be directly operated by the electric actuator to complete the manual manual operation under the condition of accident maintenance.
The role of the servo amplifier (ie position locator) is:
Signal amplification, which accepts a 4-20 mA control signal, amplifies the signal into a strong electrical signal that controls the motor's forward and reverse rotation, and controls the actuator to achieve forward or reverse rotation.
There are two modes for servo amplifiers to choose from:
A. A servo amplifier function on the control panel of the actuator itself is compact and does not need to occupy the space behind the instrument panel. Installation and debugging are relatively simple (ie, electronic integration).
B. Another type of position locator that is placed separately, installed behind the instrument panel, is a more traditional application method, which is easier to repair and replace (ie, discrete proportional adjustment type).
The electric actuator is coupled to various valve bodies to form various regulating valves.