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What is the Pneumatic Actuators?

What is the Pneumatic Actuators?

Sep 26,2022
Pneumatic Actuators
In the text, we are going to discuss the movement of pneumatic actuators. We will carefully study the operation and application of the most common spring of pneumatic actuator/diaphragm linear pneumatic actuators.

First of all, let's look at a general actuator. What are actuators? Briefly, the actuator is a kind of equipment for moving or operating objects.

Actuators make our lives easier every day, and they are the main force in the industry. For example, your dentist uses an actuator to move the chair up and down.

Type of actuator classified by energy category

Based on the definition of energy source, there are three typical types of actuators used in the industry.

Typical actuators in the industry include:


Liquid pressure


Let's continue the focus of our article, the pneumatic actuator. The pneumatic actuator converts the energy in the form of compressed air into motion.

Type of the actuator (by its motion)

Pneumatic actuators are classified by their movement type. They are either linear or rotating.

A linear pneumatic actuator can move something in a straight line. For example, a rod moves in and out of the cylinder in a straight line through pneumatic energy.

Rotating the pneumatic actuator puts something in a circular motion. For example, the rod in the gear rack drive system is used to generate rotational motion.

Let's look at some examples of how rotating and linear pneumatic actuators operate because each actuator has many different types.

1)Rotate the pneumatic actuator

Blade and rack gears are very common in rotary pneumatic actuator categories.

1-1)Leaf actuator

The blade actuator has a cylindrical chamber in which the movable blades are mounted on the shaft. The pressurized pneumatic air applied to the side of the blade rotates it during the stroke.

1-2) Rotation and small rotation

The rack and pinion actuators use the pistons connected to the rack gear. When air pressure is applied, the piston and rack move linearly, rotating the pinion and drive shaft.

2) Linear motion control device

In-line air movement control device category, reinforced/diaphragm type, and active block type emergency.

2-1) Active citadel

The piston-type pneumatic actuator uses the piston in the cylinder. The movement of the piston is caused by the application of air pressure that moves the piston upward.

Removing the pneumatic pressure causes the piston to move downward due to the pressure of the spring. This action is known as the Air-to-Retract.

Air extension movements can also be achieved by rearranging the springs, pistons, and pneumatic supplies.

2-2) Spring / diaphragm

The spring/diaphragm pneumatic actuator may be the most common actuator used to operate industrial process control valves.

The spring/diaphragm pneumatic actuator consists of a diaphragm and plate connected to the actuator rod. A flexible diaphragm is enclosed in a pressure-resistant housing.

Pneumatic pressure enters the housing and applies pressure to the diaphragm. As the air pressure on the diaphragm increases, the force applied to the spring increases, causing the actuator rod to move.

Lowering the pressure will lead to an expansion diaphragm.

The actuator rod moves the valve in or out of the valve body.

Under pneumatic operating conditions, the spring forces the valve to close.

The air pressure on the diaphragm creates a force that overcomes the force of the spring and opens the valve.

By rearranging the spring air sources, this type of actuator can fail to open or close upon loss of air pressure.

If you have any questions about pneumatic actuators or want to purchase pneumatic actuators, welcome to contact us.

UG Controls is a custom valve actuator and accessories manufacturer.  The main business is all kinds of automation equipment and technology entry and exit. UG Controls is a proprietary business solution, comprehensive chemical engineering, water, petroleum and natural gas, power plants, manufacturing, food, and beverages, etc.
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