What is a pneumatic actuator?
Introduction to pneumatic actuators
As we all know, actuator is one of the very important knowledge points in our life, but in some textbooks or works, some knowledge points about actuator are worth discussing. Today, we will briefly introduce pneumatic actuators in the actuator type.
Pneumatic actuator actuator and adjusting mechanism is a unified whole, its actuator includes film, piston, fork and rack and pinion. Piston stroke is long, suitable for large thrust occasions; Film stroke is small, can only drive the stem directly. Fork pneumatic actuator has large torque, small space, torque curve is more in line with the characteristics of valve torque curve, but not very beautiful; Often used for high torque valves. Rack and pinion pneumatic actuator has the advantages of simple structure, stable and reliable action, safety and explosion-proof. It is widely used in power plant, chemical industry, oil refining and other production processes with high safety requirements.
The working principle of pneumatic actuator
When the compressed air enters the pneumatic actuator from the nozzle of the A tube, the gas pushes the double piston to move in a straight line along the two ends (cylinder head end). The rack on the piston rotates the gear on the rotating shaft 90 degrees counterclockwise, and the valve opens. At this point, the pneumatic implementation valve at both ends of the gas with B tube. Instead, when compressed air enters both ends of the pneumatic actuator from port B, the gas pushes the double plug to the middle, the rack on the piston rotates the gear on the rotation shaft 90 degrees clockwise, and the valve closes. At this time, the gas in the middle of the pneumatic actuator is discharged with the nozzle of A tube. The above is the standard transmission principle. According to user needs, the pneumatic actuator can be installed with the opposite transmission principle of the standard type, that is, the selection shaft rotates clockwise to open the valve and counterclockwise to close the valve. Pneumatic actuator A nozzle is the air inlet, B nozzle is the vent (B muffler should be installed in the pipe mouth). A nozzle air intake is the open valve, and the spring force is used to close the valve when the air is broken.
Basic composition of pneumatic actuators
The type and structure of the regulating mechanism of the pneumatic actuator are roughly the same, mainly because the actuator is different. So when introducing the pneumatic actuator, it is divided into two parts: the actuator and the regulating valve. The pneumatic actuator is composed of two parts: the actuator and the regulating valve (regulating mechanism). According to the size of the control signal, the corresponding thrust is generated to promote the action of the regulating valve. The regulating valve is the regulating part of the pneumatic actuator. Under the thrust of the actuator, the regulating valve produces a certain displacement or Angle to directly regulate the flow of fluid.
Characteristics of pneumatic actuators
1. Double piston gear compact, rack structure, high meshing accuracy, high efficiency, constant output torque.
2. Aluminum cylinder block. Piston and end cap are light in weight compared with actuators of the same specification structure.
3. The cylinder is made of extruded aluminum alloy, which is treated by hard anodizing. The inner surface is hard and the strength is high. Sliding bearing is made of low friction material, avoid direct contact between metals, low friction coefficient, flexible rotation, long service life.
4. Install pneumatic actuators and valves. According to the international standard connection size ISO5211.DIN3337 and VDI/VDE384545, can be exchanged with ordinary pneumatic actuators.
5. Air source hole conforms to NAMUR standard.
6. Pneumatic actuator bottom shaft assembly hole (pneumatic actuator)ISO5211 standard) into a double square, convenient valve linear or 4511 standard Angle installation.
7. The top and top holes of the output shaft meet NAMUR standards.
8, both ends of the adjustment screw can adjust the opening Angle of the valve.
9, the same specifications of double acting type, single acting type (spring reset).
10, according to the valve needs to choose the direction, clockwise or counterclockwise rotation.
11. Install solenoid valve according to customer's needs. Locator (opening indicator). Returner. All kinds of limit switches and manual operating devices.
