Electric Actuators vs Pneumatic Actuators

There are different applications for each type of actuator and different reasons to use each type. This article will help you to understand the differences between electric and pneumatic actuators, what advantages and disadvantages they each have and when to choose either one for the best results.

What is an Actuator?

An actuator is a device that creates movement based on a signal or instruction it receives. It uses power sources like electricity, hydraulic pressure, or pneumatic (air) pressure to create mechanical motion. Essentially, an actuator is what makes things move or operate.

In various applications, actuators are essential for controlling and automating mechanisms. Actuators enable precise regulation of processes by operating components, like valves, to manage the flow of fluids such as oil or water, or gas, through a pipeline. 

Actuators can have two different types of motion: 

• Linear motion is movement that is forward or backwards in a line. They are found in production lines and often in the oil and gas, and mining industries.
• Rotational motion is where an actuator can rotate an item within a 360 degree arc of movement. An actuator with rotational motion can be used to control the opening or closing of a valve, to allow the flow of liquids or gases.

An actuator gets a signal from a control system, which is usually an electrical panel called a ‘programmable logic control’ or PLC for short. The signals are sent via transmitters and tell the actuator what to do, such as when to open or close a valve. 

There are three main kinds of actuators. Electric actuators which convert electrical energy into motion, pneumatic actuators which use compressed air to provide motion, and hydraulic actuators which utilise liquid to create motion. 

What is a Pneumatic Actuator?

A pneumatic actuator is a device that converts the energy from compressed air into mechanical motion. Pneumatic actuators are primarily used for linear motion and rotational motion of up to 90 degrees, exerting force to push or pull components. For instance, a spring diaphragm linear actuator utilises air pressure to move a rod, or for rotating ball and butterfly valves, common uses for a pneumatic actuator. This type of actuator is effective in applications requiring repetitive motion, such as managing the flow of gases or liquids through pipelines.

Pros and Cons Of Using A Pneumatic Actuator

Pneumatic actuators are extremely reliable and hard working, but there can be some pros and cons to using them with your equipment, such as the need for different actuators depending on the size of the job, which can be costly. Pneumatic actuators are used extensively in water treatment and chemical treatment industries.

What Is An Electric Actuator?

An electric actuator is a device that converts electrical energy into mechanical motion, capable of exerting both rotational and linear motion. This precision makes it ideal for various applications, such as clamping, holding, and controlling the motion of machinery and equipment. For example, electric actuators are commonly used to control the opening and closing of valves in the oil and gas industry.

Electric actuators use an electric motor to drive either an internal or an external gearing system (gearbox) that transforms rotational forces to linear motion via helical screw spindle.

Electric actuators are driven by an electric motor, which can be controlled to change speed through a Variable Speed Drive (VSD). This allows for accuracy and precision in moving or clamping. For example, our Maxtorque series of electric actuators are used for tasks such as opening and controlling process systems used in the chemical, water, oil & gas industry.

Pros and Cons Of Using An Electric Actuator

As with the pneumatic actuators, there are some real advantages and some less than ideal factors when utilising these actuators. They are used in water management to regulate flow rate and pressure and their precision is well-used in the production and packaging of pharmaceuticals and in the food and beverage manufacturing industries. 

Key Differences Between Electric and Pneumatic Actuators

In general, actuators are designed to translate energy into motion. However, there are some key differences between pneumatic and electric actuators. These differences often determine their application and uses.

• Power source: Pneumatic actuators require air supply to operate. Electric actuators require electricity.
• Component size: Pneumatic actuators are generally smaller than electric actuators.
• Design: The design of a pneumatic actuator is far more simple than its electric cousin. Pneumatic actuators transform energy into motion with little finesse or control, which means they don’t need to be complicated. Electric actuators often have precision jobs they perform, and hence their design is far more technical.
• Force & Speed: The force of a pneumatic actuator depends on air pressure, but the speed is considered high. An electric actuator relies on screw pitch/lead for force, and the speed of such an actuator is considered slow and precise. If more torque  is required by an electric actuator, they can be coupled with an external gear box. The gear box is used to open and close a valve either rotationally or linearly. 
• Efficiency & Cost: Pneumatic actuators are not very efficient in comparison to electric ones, but they do have a low initial cost for setting up. Electric actuators are very efficient but have a high set up cost. However, this high setup cost is offset by the low overall cost during the life of the actuator.
• Temperature Range: Pneumatic actuators generally perform well in higher ambient temperatures, but they can be less efficient in extremely cold environments due to issues like air freezing. Electric actuators, on the other hand, can operate effectively in much lower temperatures. Temperature range for pneumatic actuators can vary based on the o-ring you have. Standard temperature range for our pneumatic actuators are -20°C to +80°C. High temperature o-rings can allow a temperature range from -15°C to +150°C, while a cold temperature o-ring allows a range of -60°C to +80°C. Our electric actuators are rated from -20°C to +80°C.
• Accuracy & Repeatability: Electric actuators are known for their high accuracy and repeatability, making them ideal for tasks requiring precise control. Pneumatic actuators, while effective for high-force applications, typically offer less precision and repeatability.
• Environment and Noise: Pneumatic actuators work very well in harsh environments but they are quite noisy. Electric actuators are quiet, in comparison. 
• Safety: Electric actuators and pneumatic actuators both have their pros and cons regarding safety. Pneumatic actuators are considered safer because they have spring-return failsafe options which are not as easily implemented with electric actuators, however, Fluidflo's Maxtorque range of electric actuators have built in super-capacitors for failsafe operations. On the other hand, electric actuators are considered safer than pneumatic in emergency stop applications as they don’t rely on trapped air to hold the cylinder in place.The load is held more reliably as there is no leakage between the cylinder and the valve. However, electric actuators are vulnerable to overheating during prolonged use.

Choosing the Right Actuator

Not all actuators are created equal. Each has their own advantages and disadvantages, as we've seen, which lends itself to understanding how to choose the right actuator for the job at hand. Selecting the right actuator involves evaluating several key factors to ensure optimal performance for your specific application. Consider the following factors:

• Precision: Required level of accuracy and control.

• Force: Amount of force needed for the task.

• Speed: Desired speed of movement.

• Power Source: Availability of electrical power or compressed air.

• Environmental Conditions: Exposure to elements, temperature, and other environmental factors.

• Cycle Duration Times: this is the duration of operations per hour.

Understanding these factors will help you determine whether an electric or pneumatic actuator is the most suitable choice for your needs.

When to Choose an Electric Actuator

Electric actuators are ideal for applications requiring precise control and accurate positioning, such as in oil and gas, water treatment, and chemical processing. Their ability to provide consistent and adjustable speed makes them well-suited for managing complex valve operations where exact flow regulation is crucial. 

Additionally, electric actuators integrate seamlessly with automated control systems, offering advanced control and monitoring capabilities. Their reliability and minimal maintenance needs make them practical in environments with readily available electrical power, where reducing downtime is essential for maintaining operational efficiency. They are also advantageous in colder environments, where pneumatic actuators might suffer from efficiency loss due to factors like air freezing.

When to Choose a Pneumatic Actuator

Pneumatic actuators are well-suited for applications involving repetitive motion where precision is not the primary concern. In industries such as water treatment and chemical processing, pneumatic actuators excel due to their ability to handle high force operations and rapid movements efficiently. For example, in water treatment plants, pneumatic actuators manage the frequent opening and closing of large valves to regulate water flow, ensuring consistent and reliable operation. 

These actuators are advantageous in environments where combustion risks need to be minimised. Since they operate using compressed air, they eliminate the risk of ignition associated with electrical actuators, making them suitable for explosive or flammable environments. The durability and high force capabilities of pneumatic actuators make them a dependable choice for managing demanding industrial processes where speed and strength are critical.

If you want to learn more about electric actuators or pneumatic actuators,  then we invite you to speak to one of our experts here at Fluidflo Valve Solutions. We take pride in the quality of our products and the knowledge we have to share.