We have Xhiter Anckeleman as the person to thank for the first actuators. In particular, he introduced the pneumatic and hydraulic actuation systems. He made these inventions during the time of World War II to create better breaks.
Today, you’ll see actuators in different applications across all industries. We also now have electricity-based systems along with other types of actuators.
How far has technology advanced since 1938? What are the differences between electric, pneumatic, and hydraulic actuators? Keep on reading to learn how they work and what are their advantages.
Hydraulic actuators are the most popular type, especially in high force applications. They’re quite common in construction, cargo, military, and transportation industries.
How It Works
The most common type of hydraulic actuators uses incompressible liquid in a piston-cylinder configuration.
The compression transfers the pressure into motion. It then moves the piston inside the hollow cylinder. The piston goes back to its original position by a spring-back force.
In most cases, that liquid is a form of oil. Oil is difficult to compress. As such, it allows hydraulic systems to transfer higher amounts of energy by volume.
To go into detail, the spring force usually holds the piston in the closed position. A hydraulic supply line supplies fluid into the lower chamber, increasing the pressure.
The pressure then pushes the piston in the opposite direction of the spring force. As the spring compresses, the valve opens.
Conversely, as the liquid exits, the pressure in the chamber decreases. The spring pushes the piston to its original position, closing the valve again.
The incompressible nature of the oil makes hydraulic actuators more suitable for heavy-duty tasks. They produce 25 times more forces than pneumatic cylinders of the same size. These machines can also hold constant force and torque without having to need more fluid.
Hydraulic systems are also quite safe and secure to operate. They are easy to control. And, you can even place their pumps and motors at a farther distance without much loss in power.
Hydraulics, however, have lots of parts to maintain. They have different pumps, motors, a fluid reservoir, heat exchangers, release valves, and many more.
Hydraulic fluid leaking is also a serious risk. The oil hard to clean, and it might damage the surrounding components and machines.
For some, the biggest issue is the cost. Hydraulic systems are big investments, but if you use them the right way, they pay back over time.
Pneumatic actuators are popular for applications involving the opening and closing of valves. You’ll see them in packaging machinery, combustible automobile engines, and air compressors. They’re also common in the transportation industry.
How It Works
Pneumatic systems go way back into 3000 B.C. when people used compressed air to start a fire. Today, in actuators, it converts the energy of pressurized gas into mechanical motion. They work the same way as hydraulic actuators, except the driving force here is air.
The compressed air enters the chamber through a valve, building up the pressure. As the pressure builds up higher than the atmospheric pressure, it moves the piston in a linear direction.
Pneumatic linear actuators have two types: single-acting and double-acting. The concept is the same but they differ in the return method and the number of ports.
A single-acting system only has one port, which supplies the air into the chamber. A spring positioned either inside or outside pushes the piston back to position.
A double-acting system has two ports and no spring. One port supplies air to move the piston. Meanwhile, the other port supplies air on the opposite side to push the piston back into place.
Pneumatic actuators are safer than other types, especially in applications dealing with extreme temperatures. Because it uses compressed air, it doesn’t require ignition or electricity.
They’re simple machines, but they’re the fastest on the market, allowing for higher cycle times. Double-acting systems provide force even more quickly.
Pneumatic systems tend to be the cheapest option, as well. To add to that, they’re durable and easy to maintain.
They’re better for light to medium applications because it supplies limited power. The compressibility of air and losses in pressure make them less capable of producing greater forces.
Oil or lubrication can also contaminate the air. You should also keep the air-water content in check to avoid performance issues.
Electric actuators were initially much weaker. Thanks to the advances in technology, though, they’re now reliable machines. They’re common in the automotive, wastewater treatment, and food industries.
How It Works
This type of actuator converts rotational energy to linear force. An electric motor creates rotary motion, which a gearbox then reduces to increase the torque. The rotation of a part called the ball screw nut creates a linear motion of the attached hollow piston rod.
An electric drive controls the motor. This allows users to control the rotation speed and, in turn, the linear speed. Users can also program the actuator to return to the original position, stop, or move.
Out of all the three types of actuators, electricity-powered systems are the most precise. They don’t have tolerances like backlash, slack, and flex.
They also have fast response times, allowing for quick, precise, and quiet work. Users can program the positioning and force output with ease. Electric actuators provide complete control over the speed, stroke lengths, and such.
Electricity is clean energy, as well. There are no risks of contamination and leakage.
Electric actuators are best for light work. They don’t provide the same level of power you can get with pneumatic and hydraulic actuators. The initial investment costs are greater, as well.
They’re also not suitable in all kinds of conditions. The designs of the machines can be quite complicated, too. This leads to higher maintenance requirements.
Get High-Quality Actuators
Electric, pneumatic, and hydraulic actuators all play important roles in every industry. Consider your needs to determine which one best fits your purpose.
What also matters is the quality of the machinery you choose. Contact us today and let us know your requirements.