Electric actuators are widely used in real life. For example: electric power, metallurgy, petroleum, chemical industry, paper making, sewage treatment and other industries. Electrically drive valves and similar equipment to accomplish tasks beyond manpower. For example: Torque requirements are too large or the valve is in a bad environment.
Electric actuator is also an important executive unit in the industrial control system. It can provide a driving device for linear or rotary motion. It uses some driving energy and works under some control signal. Electric actuators use liquids, gases, electricity or other energy sources and convert them into driving functions through motors, cylinders or other devices.
With the improvement of the level of industrial automation equipment, electric actuator is an important equipment in the production of industrial enterprises. Its technical level and quality stability are the basis to ensure the sustainability, safety and production of industrial enterprises. Customers have very high requirements for reliability, safety, stability and performance of electric actuator products. Users tend to choose products with certain brand awareness and cooperate with companies with certain experience and strength, which results in higher market barriers for new products entering the industry.
Electric actuator is generally composed of control circuit and actuator, which are completely independent parts in the circuit. It can receive the control signal from the regulator, and convert it linearly into mechanical angle or linear displacement. It is used to control the regulating mechanism such as damper, baffle and valve, so as to realize automatic control. There are many kinds of valves and their working principles are different. Generally, the opening and closing control is realized by rotating the angle of the valve plate and lifting the valve plate. When matching with the electric actuator, the electric actuator should be selected according to the type of the valve.
1. Angular stroke electric actuator (angle < 360 degrees)
Electric actuator output shaft rotation is less than a week, that is, less than 360 degrees, usually 90 degrees to achieve valve opening and closing process control. This kind of electric actuator can be divided into direct connection type and base crank type according to the different installation interfaces.
1) Direct connection type: refers to the installation form of direct connection between the output shaft of the electric actuator and the valve stem.
2) Base crank type: refers to the form in which the output shaft is connected with the valve stem through the crank.
This kind of electric actuator is suitable for butterfly valves, ball valves, cock valves, etc.
2. Multi-turn electric actuator (angle > 360 degrees)
The rotation of the output shaft of the electric actuator is greater than one week, that is, more than 360 degrees. Generally, it needs more than one circle to realize the control of the valve opening and closing process.
This kind of electric actuator is suitable for gate valves, globe valves, etc.
3. Straight-stroke electric actuator (linear motion)
The motion of the output shaft of the electric actuator is linear, not rotational.
This kind of electric actuator is suitable for single-seat control valve, double-seat control valve, etc.