What exactly is an air cylinder?

Air cylinders, also known as pneumatic cylinders, are systems that convert the energy of air into a linear or rotary motion by means of a pressing motion. Thanks to this force, a cylinder can push, pull, lift or rotate various parts directly or indirectly.

The cylinders contain different parts that vary depending on the type and design of the cylinder. But the goal is always to set the mechanism attached to the cylinder in motion.

What exactly is an air cylinder?

Pneumatic cylinders, also known as pneumatic actuators, are products used to deliver linear or rotary movements and forces to automated systems, machines, and processes, for example in industrial applications.

Pneumatic cylinders and actuators are a simple way to apply force and generate precise linear and rotational motion and can be used in harsh environments, such as extreme temperatures. They are lightweight and require little maintenance, but generally produce less power than hydraulic or electrical systems, but nevertheless remain a cost-effective alternative.

Different types of air cylinders

The most common type of air cylinders are single-acting, double-acting, and piston rodless cylinders. Each type of cylinder has its own operation and application that we would like to list.

A single-acting cylinder exerts force in only one direction, compressive or tensile force. This means that the movement of the cylinder with pressure only moves in one direction. It allows the air cylinder to clamp, eject and lift. This type of cylinder is often used in the following applications:

• Metal industry: Single-acting cylinders hold metal sheets in place during cutting or drilling (clamping). 
• Packaging industry: Single-acting cylinders eject finished packaging from molds (ejection). 
• Agriculture: For lifting work such as in pneumatic lifting systems for agricultural machinery (lifting).

A double-acting cylinder exerts force in multiple directions, both compressive and tensile force. This means that the cylinder works in both directions with pressure and tensile force. It allows the air cylinder to make a more precise movement and also has finer force control. This type of cylinder is often used in the following applications:

• Automotive industry: Double-acting cylinders are used in assembly lines to drive mounting arms (precise movement). 
• Textile industry: Double-acting cylinders control looms and other equipment (force control). 
• Logistics: In conveyor systems for moving goods (precise control).

• Electronics industry: Piston rodless cylinders are used for the linear movement of electronic components in assembly lines. 
• Beverage industry: For lifting and moving heavy drums and bottles.
• Paper: In cutting machines for linear paper cutting.

Regulations regarding air cylinders

Actuators and cylinders are produced according to "house standards" – which are likely to be unique to a particular manufacturer – or according to generally accepted or international standards. NFPA standards for pneumatic actuators are used in North America, while ISO is the standard common in Europe. 

ISO stands for International Organization for Standardization. The purpose of ISO standards is to ensure that products, services and systems meet the highest levels of quality, safety and performance.

A single-acting cylinder makes a 'working stroke'. The recurrent stroke must be made by its own weight or by an internally mounted spring. A good example of a cylinder with an internal spring is a round single-acting cylinder ISO 6432.  A single-acting cylinder also has only one air connection.

A double-acting cylinder is a cylinder in which the input and output stroke can be a 'working stroke'. Compared to a single-acting cylinder, these cylinders also do not have an internal spring to return the piston rod to its original position. A double-acting cylinder also has two air connections.