Views: 209 Author: Site Editor Publish Time: 2021-04-19 Origin: Site
There are five types of electric actuators: linear electric actuators, quarter turn electric actuators, electric control valve actuators, PID electric control actuators and electromagnetic valve actuators. The first four belong to the DDZ type.
The following briefly introduces the electric linear actuator (DKJ) and the rotary electric actuator (DKZ). The function of the linear and angular stroke electric actuators is to receive the 0-10 mA standard direct current signal from the regulator or other instruments. After the actuator, it becomes displacement thrust or angular torque, which can be used to operate switches, valves, etc. to complete the task of automatic adjustment. These two types of actuators are composed of two parts: servo amplifier and actuator. Their structure, working principle and method of use are similar, the only difference is that one output displacement (thrust) and one output rotation angle (torque).
Servo amplifier is composed of preamplifier, trigger, silicon controlled rectifier components and so on. Its function is to compare the input DC mA signal with the feedback signal of the position transmitter. If the difference after comparison is zero, there is no output from the servo amplifier, the actuator is in a balanced state, and the position of the output shaft remains unchanged. If there is a deviation signal after comparison, it is amplified to enough power by the amplifier to drive the two-phase servo motor to rotate the output shaft of the reducer until the input signal is equal to the position feedback signal. At this time, the output is stabilized at the new position corresponding to the input signal.
Actuator refers to the proportional conversion to linear displacement or angular displacement according to the output of the regulator, and drives the valve and dampers to directly adjust the energy or conveying volume of the adjusted medium such as materials.
Classified by structure, the actuator refers to the pushing device of the actuator. The adjustment mechanism is the adjustment part of the actuator, which produces a certain displacement or angle.
According to the energy used, it is mainly divided into electric, pneumatic and hydraulic.
The advantages of electric motors are fast action, convenient energy, and suitable for remote transmission. The disadvantage is that special equipment is required for use in flammable and explosive situations.
The pneumatic structure is simple, fireproof and explosion-proof, low price, convenient for maintenance, but not suitable for remote transmission.
The hydraulic thrust is large but not used much.
The solenoid valve uses the attraction and release of the electromagnet to adjust the small diameter valve on and off. Its characteristics are simple structure and low price. Generally, fluid with a certain pressure is required. If the pressure is too high, it cannot be started, and if it is too small, it cannot be sucked in.
Electric control valve is an important executive unit instrument in industrial automation process control. With the increasing degree of automation in the industrial field, it is being used more and more in various industrial production fields. Compared with the traditional pneumatic control valve, it has obvious advantages: the electric control valve is more energy-saving (consumption of electricity only when working), environmentally friendly (no carbon emissions), and quick and convenient to install (no need for complicated pneumatic pipelines and air pump workstations).
In addition to electric control valves, the related content of electric motor actuators also includes valve positioners, electric conversion valves and voltage regulators.
