Pneumatic Actuator vs. Hydraulic Actuator: Key Differences?

It is easy to find a variety of actuators in the market today. There are pneumatic, hydraulic, and electric actuators employed in various industrial applications for different purposes. But the most common of them is the pneumatic and hydraulic ones. Learning about pneumatic cylinder vs hydraulic cylinder helps decide which one to employ in a China Valve for a specific application.

The actuator’s energy source can be either hydraulic (fluid-based), pneumatic (air-pressure based), or electric. However, each energy source has a distinct set of advantages and disadvantages. To be able to employ the suitable device in a specific application, it is essential to understand everything about hydraulic actuator vs pneumatic actuator.

So, let’s get started!

What Is A Pneumatic Actuator?

A pneumatic actuator uses compressed air to operate. It does not require a motor, so it invites no hazardous materials or contamination. Pneumatic cylinders are driven by air pressure instead of fluid. But since the air is sometimes less efficient as a power source, it may cause the device to lose pressure.

The compressor powering the pneumatic actuated valve should be nearby and run continuously because the air may contaminate by equipment lubricants, thus increasing the risk of damage.

Pneumatic cylinders offer high reliability, consistent liner motion with accuracy tolerance within 0.1 inches, and repeatability tolerance within 0.001 inches. They can perform effectively even in extremely high or low temperatures, which may cripple the fluid-based hydraulic cylinders. Since these devices have no motor and employ no hazardous material, they can easily adhere to the mechanical safety requirements.

Advantages of Using a Pneumatic Actuator:

• Pneumatic actuators are ideal for operations requiring low speed and pressure.
• They can quickly meet mechanical safety requirements.
• These devices are suitable for applications requiring repeated operations.
• They are perfect for applications involving extreme high or low temperatures.
• A pneumatic actuator is cost-effective and requires little to no maintenance.
• Compared to a hydraulic actuator, the pneumatic one offers high-speed motion.

What Is A Hydraulic Actuator?

In a hydraulic actuated valve, fluid is used to operate. It means it can hold torque and force without continuous pressure application. But the sad part is that it is prone to leakages, and a leaked fluid may invite contamination. Since these cylinders produce tremendous force by handling higher pressures, they are ideal for operation in heavy construction equipment.

The best thing about hydraulic actuators is they can produce as much as 25 times more force than pneumatic actuators and have higher horsepower per weight. One of their significant perks of a hydraulic vs pneumatic actuator is its ability to hold torque and force without continuous application of fluid pressure from the power source.

However, hydraulic actuators are prone to leakages, which may cause contamination and damage to the device’s internal and external parts. Besides, it takes various other equipment to operate hydraulics – pumps, motors, fluid reservoirs, etc. They are also very noisy when outfitted with noise-reducing equipment.

Advantages of Using a Hydraulic Actuator:

• Hydraulic actuators are more efficient than pneumatic actuators.
• They can produce a force 25 times greater in a globe butterfly valve.
• They are suitable for all applications requiring higher pressure.
• A hydraulic actuator can maintain constant power and torque.
• It offers a precise linear motion compared to a pneumatic actuator.

Differentiating Between a Pneumatic and a Hydraulic Actuator:

Understanding the difference between a pneumatic and a hydraulic actuator is crucial as it helps choose the ideal equipment for a particular application. While hydraulic actuators are prone to leakages, involve high initial investment and maintenance, and make a workspace dirty and cause accidents, pneumatic actuators offer limited strength and work capacity and have a shorter life cycle.

Here is a quick table to better understand everything about a hydraulic cylinder vs pneumatic cylinder to make the right decision when employing either of these two in a certain application:

BASIS OF DIFFERENCE	PNEUMATIC ACTUATOR	HYDRAULIC ACTUATOR
PURPOSE	A pneumatic actuator uses compressed gases to convert energy into motion. These confined pressurized systems inside a 3 PC ball valve use moving air and other gases for smooth operation.	A hydraulic actuator uses incompressible hydraulic fluid to convert hydraulic into mechanical energy. These confined pressurized systems use moving liquids for smooth operation.
COMPRESSIBILITY	Since gases are compressible, there is a delay in force and movement in a pneumatic actuator.	Since liquids are not compressible, there is no delay in force and movement in a hydraulic actuator.
REQUIREMENTS	Pneumatic actuators need a compressor.	Hydraulic actuators need hydraulic fluid, cylinder, piston, pump, and valves.
APPLICATIONS	These devices are used in precision drills, moving and controlling machinery, air brakes, tampers, nail gun, and dentist chairs.	These devices are used in dump truck lifts, body blood, cars, and jaws for lifting cars.
SUITABILITY	It is ideal for applications requiring less power and more consistency, reliability, and linear motion.	It is ideal for applications requiring ball valve floating type at higher force and less precision or consistency.
REPEATED OPERATIONS	Pneumatic actuators are preferred for repeated operations.	Hydraulic actuators are not preferred for applications demanding repeated work.
PERFORMANCE	These devices can perform effectively even in extremely high or low temperatures.	These devices cannot perform under extraordinarily high or low temperatures.
HORSEPOWER-TO-WEIGHT RATIO	This ratio is lower for pneumatic motors.	This ratio is higher for hydraulic motors.
OPERATING SPEED & PRESSURE	A pneumatic actuated ball valve can function at lower pressures and speeds than hydraulic cylinders.	Hydraulic actuators are suitable for applications requiring a higher force and operating speed.
WORKING ENVIRONMENT	They are ideal for environments where hygiene and green practices are paramount.	They are ideal for environments requiring extensive or heavy-scale lifting work, such as mining and construction.

While pneumatics is a preferable choice in medical tools, dental drills, and small-scale robotics due to their flexibility of airflow and precision in use, hydraulics are suitable for high-force applications. They are often found in mining and construction environments as they offer constant torque and force despite speed variations and help maintain positional rigidity.

Pneumatics V ball valve is suitable for environments where hygiene and green practices are paramount. But, they are impractical for extensive or heavy-scale lifting work.

Final Thoughts

Pneumatic and hydraulic actuators are similar in that both use a fluid to channel the mechanical energy and in the executions, terminology, and components. The two power circuits need a specific type of pump and some valves for force and velocity control of the actuators. But, the differences between the two help determine how and where each can be employed.

While technological advances continue to enhance energy efficiency and performance on both sides, the difference between hydraulic and pneumatic cylinder boils down to context. Hopefully, the above features help everyone understand the various applications where they can employ either of the actuators effectively.

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