Views: 1 Author: pneumaticmfg Publish Time: 2024-12-03 Origin: pneumaticmfg
Air actuators are available in various design options. They are broadly categorized based on whether they produce a rotary or linear motion. Linear motion types are mostly piston and diaphragm-based, while rotary actuators use rack and pinion gears or vane assemblies.
In a linear air actuator, motion happens along a straight line. To produce the movement, air presses against the surface area of a movable piston. Alternatively, this can be a spring-loaded diaphragm connected to a rod.
In this type of actuator, a piston moves back and forth inside a cylinder. The piston connects to a rod, which, in turn, links it to the load (the part moved).
When compressed air enters the cylinder, its force causes the piston to move, and the actuator performs the required function. The pneumatic piston actuator can be single-acting or double-acting.
In the single-acting type, a return spring retracts the piston when air pressure reduces. The double-acting version uses pressurized air to perform the same function.
The pneumatic diaphragm actuator comprises a flexible diaphragm inside a sealed enclosure and a moving rod or actuating stem. The single-acting type includes a return spring to pull back the diaphragm at the end of a stroke.
To produce the required movement, a control valve sends a compressed gas into the area above the diaphragm. The diaphragm, now under pressure, moves downward, compressing the spring and moving the stem.
At the end of the cycle, the air exhausts from the housing. The diaphragm is no longer under pressure. The spring releases its energy and pushes the diaphragm to its former position.
In some actuator versions, compressed air flows into the opposite side of the diaphragm to push it back. These do not require a return spring.
The rotary type rotates a shaft and transfers motion to the actuating component. Most often, the device is a piston rack-and-pinion system or a vane assembly. Let’s see how each of these actuator types works.
In this type, a movable piston connects to a rack and pinion gear. When pushed by a compressed gas, the piston moves the rack gear back and forth.
The moving rack then rotates the pinion gear, and this causes rotation. Like other actuators, this movement can move a load and perform a function.
Pneumatic rack and pinion actuators have varied applications in manufacturing systems. Other uses include the control of butterfly and ball valves of large pipelines.
These actuators use a moving vane mounted inside a sealed housing. The vane has a shaft connected to it. Introducing pressurized air into the housing causes the vane to move in one direction.
The vane then moves in the opposite direction when the air is released. The back-and-forth motion rotates the shaft and performs a desired function.
Vane-type pneumatic actuators are simple in construction, compact, and less demanding to maintain than other air actuators. They’re also low-cost and more reliable.
Examples of pneumatic or air actuators
Like any other type of actuator, such as hydraulic or electric, the pneumatic actuator has both advantages and disadvantages. These should inform your choice, usually based on the intended application or device operating environment.
The advantages of pneumatic actuators are summarized below.
Rapid actuation/response time
Simple design and operation
excellent reliability i
Safe to use around flammable materials
Higher power-to-weight ratio when compared to other pneumatic actuator types
Low accuracy level
Affected by impurities, including condensation
Require the use of an air compressor
Pneumatic air actuator in an industrial setting
You can use a pneumatic or air actuator in many settings. It can be an actuator to open and close a valve, for example, or the mechanism of a power tool. Popular uses include those in the list below.
Material handling and process control equipment
Automotive and aerospace systems
In robotic systems to operate grippers, etc.
To automate the valves of wastewater, chemical, or oil and gas pipelines
Process and flow control in HVAC devices and systems
In the switching devices of power plants and other high-voltage systems
Pneumatic actuator manufacturers make all kinds of these devices. Typically, these include linear and rotary actuators. Based on the required function, one may use either type.
