Pneumatic actuators are vital to hundreds of different industries and have a wide variety of uses. To understand how to apply cylinders, you should be familiar with the basics.
This guide will answer the following questions: what is a pneumatic actuator, how does an actuator work, what are the different types available, and what is the function of a pneumatic actuator?
What is a pneumatic actuation system?
Pneumatic actuators are highly reliable, efficient, and safe sources of motion control that use compressed air or gas to convert energy into rotary or linear motion. They are especially useful for repeatedly opening and closing valves and other industrial applications where the use of electricity can create a fire or fire hazard. Actuators are commonly used to control valves that direct the movement of fluids in the chemical and process industries.
Pneumatic actuators are known by several different names, including pneumatic cylinders, air cylinders, and pneumatic actuators. Each of these terms is a synonym for the other, as they both identify the device as an air pressure-based device. Another name for a cylinder is a pneumatic plunger, where a plunger refers to a linear piston.
How do pneumatic actuators work?
Pneumatic actuators rely on some form of pressurized gas -- usually compressed air -- entering a chamber, where the gas builds up pressure. When it builds up enough pressure compared to the external atmospheric pressure, it causes controlled dynamic movement of devices such as pistons or gears. The resulting motion can be linear or circular.
Because the conversion of compressed gas to energy is highly controllable, reliable, and repeatable, pneumatic actuators are one of the most popular mechanical devices in modern industry.
Type of cylinder
There are two main types of pneumatic linear actuators - single-acting and double-acting. They are both used to push the piston, but the main difference is the return method and the number of ports.
Single-acting cylinders have a port that allows air to flow into the cylinder. The pressure builds up and pushes the piston forward or backward, depending on whether it's a push or a pull. A large spring returns the piston to its original position in preparation for another burst of pressure. The spring is either inside the cylinder or outside.
Double-acting cylinders operate without springs but instead have two ports, one at each end of the piston. The first application of pressure pushes the piston forward, a step in the shared process between the two models. Then, the second burst of pressure on the other side of the cylinder pushes the piston back into place. The device applies pressure back and forth to create a smooth linear motion.
Generally, double-acting cylinders are better suited for industrial use where speed and strength are required because they deliver more force at a faster speed. They also provide a longer lifespan before needing to be replaced. However, they are a more expensive option by comparison. Aside from the cost, single-acting cylinders have other advantages. They have simpler designs, are more compact, and require half as much compressed air to operate.
Pneumatic actuator application
Pneumatic actuators have a wide range of applications. The most common and popular use is for pistons and ignition chambers in gasoline-powered vehicles. They use the ignition of air and gasoline to create the pressure that eventually moves the pistons and converts energy into the car's crankshaft. However, most pneumatic actuators rely solely on a united pressurized gas to generate the required mechanical force.
In addition to traditional combustible automotive engines, pneumatic actuators are essential in transportation equipment such as air compressors, packaging and production machinery, mail pipes, and rail and aircraft applications. They are also critical in many other industrial environments where switch, pump or sensor control is required.
Pneumatic and electric actuators
Cylinders work with pressurized air, while electric actuators work with electricity. Electric actuators consist of a screw, a coupling and a motor, such as a stepper or a servo. The screw turns and moves the nut, causing the link or carriage to move the load. While pneumatic and electric actuators serve similar purposes, they are not directly interchangeable in every industry.
The two types of actuators differ in several other ways:
Cost: Overall, the initial cost of pneumatic actuators is lower than electric actuators, but each has its purpose and ultimately saves operating costs. Pneumatic cylinders are most cost-effective when the compressor is sized to match the number of cylinders it drives. Electric actuators offer the highest levels of efficiency at mid-scale, although they generally have lower operating costs.
Force: In a pneumatic actuator, speed and thrust are positively correlated, which means that when one increases, the other also increases. In electric actuators, thrust and speed do not have the same connection, as one decreases and the other increases. You can design them to perform differently, but this requires a higher fee.
Control: Cylinders are more suitable for industries that require force, and electric actuators provide more accurate control and positioning. Standard models of the electric variety can move precisely one hundredth to one-thousandth of an inch.
Advantages of pneumatic actuators
The advantages of pneumatic actuators stem from their overall safety and reliability. First, because pneumatic actuators can convert energy into motion without ignition or electricity, they are highly sought after and sparks and burns cannot be tolerated. In these settings, compressed air can be stored and used in an efficient and repeatable manner without posing a fire risk.
Second, because combustion-independent pneumatic actuators can be easily manufactured and are relatively simple devices, they are also very durable, require minimal maintenance, and provide a long service life when used correctly.
The above briefly introduces the advantages and classification of pneumatic actuators. If you want to buy pneumatic actuators, please contact us.
UG Controls is a professional custom valve actuator manufacturer. We use our engineering expertise and industry experience to continuously improve our products, striving to provide efficient solutions and competitive prices. UG is also a global supplier of highly engineered actuators and accessories serving the oil and gas, mining, chemical, pharmaceutical, water and power, food and beverage, and general industrial markets.