Views: 238 Author: Site Editor Publish Time: 2021-03-01 Origin: Site
Actuators are divided into air powered actuators, electric motor actuators and hydraulic actuators according to their energy form. They have their own characteristics and are suitable for different occasions. In this article, we focus on understanding the characteristics of pneumatic actuators.
The type and structure of the adjustment mechanism of the pneumatic air actuators are roughly the same, mainly because the actuator is different. The pneumatic device is mainly composed of cylinder, piston, gear shaft, end cover, seal, screw, etc. The valve actuator mounting kits should also include opening instructions, stroke limits, solenoid valves, positioners, pneumatic components, manual mechanisms, signal feedback and other components.
It can receive continuous air signals and output linear displacement (after power-on/air conversion device, it can also receive continuous electrical signals), and some can output angular displacement when equipped with a rocker arm.
The pneumatic rotary actuator has positive and negative functions.
The moving speed is high, but the speed will slow down when the load increases.
The output force is related to the operating pressure.
High reliability, but the pneumatic angle seat valve cannot be maintained after the air supply is interrupted (it can be maintained after adding a retaining valve).
It is inconvenient to realize segment control and program control.
Its maintenance is simple and adaptable to the environment.
The output power is large, and has the explosion-proof function.
The pneumatic rack and pinion actuator has a compact double-piston gear, rack-and-pinion structure, precise meshing, high efficiency, and constant output torque.
Aluminum cylinder block, piston and end cover have the lightest weight compared with the actuator of the same specification structure.
The pneumatic rotary cylinder is made of extruded aluminum alloy and is treated with hard anodizing. The inner surface is hard, with high strength and hardness. The sliding bearing made of low-friction materials avoids direct contact between metals, has low friction coefficient, flexible rotation and long service life.
Pneumatic actuator and valve installation and connection dimensions are designed according to international standards ISO5211, DIN3337 and VDI/VDE3845. It can be interchanged with ordinary pneumatic actuators.
The air source hole complies with NAMUR standard.
The shaft assembly hole at the bottom of the pneumatic actuator (in accordance with ISO5211 standard) is a double square, which is convenient for linear or 45° angle installation of the valve with a square rod.
The top holes of the output shaft comply with NAMUR standards.
The adjustment screws at both ends can adjust the opening angle of the valve.
The same specifications are double-acting and single-acting (spring return). Correspondingly, the cylinder includes single acting pneumatic cylinder, double acting pneumatic cylinder and spring return pneumatic cylinder.
The direction can be selected according to the needs of the valve, clockwise or counterclockwise.
According to user needs, install solenoid valve, positioner (opening indication), echo device, various limit switches and manual operating devices.
The control accuracy is low. The double acting pneumatic actuator cannot return to the preset position after the air supply is cut off. The single acting pneumatic actuator can return to the preset position by spring after the air source is cut off.
