What is compressed air?



Compressed air is used all around us in everyday life. It can be used in the form of blowing air or as an energy source, from the air in a balloon, riding a roller coaster to visiting the dentist.

Compressed Air is often called “The Fourth Utility” because it is an essential element to millions of businesses around the world. Compressed air is a gas mixture, which mainly consists of nitrogen (78%) and oxygen (21%). When compressed, the air is still made up of the same mixture of gases, however, it will have been forced into a smaller space, bringing the molecules closer together. The energy that gets released when doing this is equal to the energy required to force the air into the smaller space. In other words, it stores the energy for future use.


Compressed air has been used by man since at least the 3rd Century BC.  The Greek inventor Ctesibius used compressed air in an alarm clock and in a cannon that shot arrows. His protege, Hero, used it to open the gates at the Temple of Alexandria.



Air is compressed by air compressors. Air compressors draw in air at an inlet valve, they then compress the air to the required volume and release the pressurised air through the discharge valve into a storage tank. They’re powered by an engine that turns electrical energy into kinetic energy.

There are two types of air displacement that a compressed air system may operate upon:

Positive Displacement – Positive displacement air compressors force air in a chamber where the volume is decreased to compress the air. Although the internal systems vary among different machines, the method of providing the power is the same.

Some types of positive displacement compressors are better equipped for industrial workloads while others are better for hobbyists or private projects.

Dynamic Displacement – Dynamic displacement compressors utilise a rotating blade powered by an engine to generate airflow. The air is then restricted to create pressure, and the kinetic energy is stored within the compressor. These are mainly designed for large projects, like at chemical plants or steel manufacturers, so it’s unlikely you’ll be able to find one at your local mechanic.



  • Low maintenance costs
  • Can handle high loads over long periods without the risk of overheating
  • Easy to store
  • Energy efficient
  • Can be used in manufacturing processes that demand a high level of cleanliness



Nessco Pressure Systems know how important it is to have guaranteed air supply and regular service during these unprecedented times. Our service technicians are available 24/7 in case of a breakdown.

If you would like further information regarding our compressors and services, give us a call on 1300 290 638 or send us an email and one of our BDM’s will be available to help you choose the right product for your needs.

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274 Welshpool Rd, Welshpool, Perth
1300 290 638