What is compressed air?

It is important to understand what compressed air is, in order to find the right compressed air solutions. By reading this guide, you will be able to understand how the compression process works. 

About compressed air

Unlike liquids, air can be compressed, meaning that a given amount of air can be reduced by an increased pressure. It is produced by a machine with an energy source, also called a compressor.

There are very complicated compressors, but some of the simplest kind of compressors are bicycle pumps. 

With a bicycle pump, the energy source is the person pushing the lever up and down. Inside the pump, air is drawn in and compressed to approx. ¼ of its original volume. This means that the air pressure inside the bicycle tire rises four times the atmospheric pressure. The bicycle tire is therefore filled with air.


What types of compressors exists?

There are several types of compressors that can be used for various applications:

  • Piston compressors are characterized by having one or more pistons that compress the air. Piston compressors are best suited for smaller air pressure needs where they compress the air in intervals.
  • Oil-free compressors deliver oil-free compressed air. These compressors are used in situations where oil residues can damage production quality or render products unusable.
  • Screw compressors compress air by means of two counter-rotating screws moving in a housing. Screw compressors are used in a variety of industries.

How to indicate compressed air

How is the air pressure inside the bicycle tire then stated?

There are three ways to state air pressure: One way is like four times the atmospheric pressure.   The absolute atmospheric pressure is approx. 100 kPa. When you enter it four times, it is written as   400 kPa(a). • Another way is as overpressure, 300 kPa(e) • The last way is 300 kPa, where it is considered as overpressure.

Read more about compressed air and compressors here