Fundamentals of pneumatics

The term pneumatics comes from the Greek work "pneuma", meaning wind or breath. It refers to the use of compressed air or systems driven by compressed air in an engineering application. A modern pneumatic system in automation technology consists of subsystems for:

• generating and providing the compressed air (compressors, radiators, filters),

• distributing the compressed air (ducts, pneumatic tubing, coupling pieces),

• controlling the compressed air (pressure regulators, directional control valves, stop valves),

• performing work using the compressed air (cylinders, rotary drives).

Compressed air is most often used to perform mechanical work, i.e. to carry out movements and to generate high forces.

Pneumatic drives serve to convert the energy stored in the compressed air into kinetic energy.

For the most part, cylinders are used as pneumatic drives. They have a sturdy design, are easily installed, offer a favourable price/performance ratio and come in a wide choice of variants. These advantages have opened up a wide range of applications for pneumatics in modern engineering. The following table outlines further advantages.

Physical fundamentals

Air is a gaseous mixture with the following composition:

• approx. 78% nitrogen

• approx. 21% oxygen

It also contains traces of water vapour, carbon dioxide, argon, hydrogen, neon, helium, krypton and xenon.

To help you understand the laws of air, the physical variables that occur in this context are listed below. All specifications are in the "International System of Units", or SI for short.