COMPRESSORS 101: HOW DOES AIR COMPRESSION WORK?

Air compressors have a wide variety of applications at every level of industry. Some handy people may even have air compressors at home for construction and maintenance projects.

As common as compressors are, however, the science behind them can seem dense. Even regular users may not have a clear picture of how they work. Here are some of the basic principles behind air compression and the most common mechanisms in use today:

How Compressors Work

While most air compressors are designed to handle air at a specific pressure, all of them take advantage of the same basic principle: Boyle’s law.

According to this scientific law, so long as the surrounding temperature remains constant, the air pressure within a container is inversely proportional to the volume of the container. As a result, reducing the volume of even a small container can generate high pressure, creating a great deal of untapped energy.

Air compressors exploit this principle to maximize the energy contained in pressurized air. The electrical energy needed to compress air becomes kinetic energy contained in the heavily pressurized air. The kinetic energy in the compressed air can then be used to power a variety of tools and machines, from industrial equipment to small drills and spray guns.

Finding the Right Mechanism

There are several different methods for compressing air, but most compressors use pistons or a rotary mechanism.

In a piston compressor, an electrical or gas-powered motor rotates a crankshaft, pushing the piston in and out of a smooth cylinder. When the piston enters the cylinder, it reduces the cylinder’s volume, increasing the pressure of the air within it.

The compressed air is then released through specialized valves on the side of the container and stored in an external receiver tank, from which the pressurized air can be taken and used to power a machine or tool. Many piston compressors include a valve switch that stops the piston once the machine has reached the desired air pressure. 

Rotary compressors, on the other hand, use rotary mechanisms to compress air, providing a steadier stream of compressed air. Rotary compressors come in two flavors: rotary vane and rotary screw.

Rotary screw compressors have two parallel rotors with external screws that intersect longitudinally, separated by a critical minimum clearance. When the compressors is running, these two rotors mesh together, compressing the air.

In a rotary vane compressor, a single rotor with longitudinal slots houses offset sliding vanes, which slide in and out of the rotor to form compression pockets. The mechanism is simpler, less sensitive, and more efficient than the rotary screw, giving this compressor a longer lifespan and a lower cost over time. 

Nuts and Bolts

As you might expect, air compressors have specific maintenance needs. They need to be regularly lubricated to ensure that the piston and crankshaft operate smoothly and reduce wear on the cylinder. Their cooling systems also need to be regularly monitored so that the air remains at a constant temperature.

No matter what you’re working on, there’s a compressor that meets your needs. To learn more about how rotary vane compressors work and how they can benefit your business, don’t hesitate to contact us today.