How Do Air Compressors Work?

An air compressor includes an electrical motor that compresses the air into a tank. The compressed air can be released at the picked pressure when required. How does an air compressor work? What are the criteria for choosing a suitable gas compressor? Well there are a range of various compressor types.

Let’s continue with a summary. Normally compressors used in automation and workshops are the so-called positive displacement compressors. When air is drawn into a container and the volume of that space is minimized, here pressure is induced. For this article we want to limit ourselves to this type of compressor. Let’s take a closer look at the reciprocating compressor.

The crankshaft turns which moves the piston inside the round chamber. An inlet valve also called an intake valve permits atmospheric air to enter the cylinder. This is done during a suction blow from the cylinder. The vacuum valve opens or deflates at high pressure during the pressure paddle.

The air is heated up when it is compressed. This is a problem for every single compressor. The result is not simply a less efficient compression cycle, but also the danger of a real explosion if any flammable compounds, such as oil or lubes, touch with the piston and air. Therefore, the pressure of a single phase compressor is limited to an output pressure of about 10 bar or 145 lbs To attain higher pressures, you can use a multi-step compressor.

In a two phase compressor, the big piston builds the first stage. The air that exits the first stage can now be cooled prior to getting in the second phase. With a two-stage compressor, you can attain pressure in excess of 20 bar or 290 psi. Multistage compressors can also be used with high-power water-cooled jackets to avoid getting too hot. Based upon its working principle, the reciprocating compressor supplies just pulse compressed air.

This type of compressor is used in conjunction with a tank. The use of a tank supplies the advantage that the compressor can be operated with a two-point controller, resulting in less power consumption and wear.

The diaphragm compressor comes from the piston compressor family. Here the suction chamber of the piston is shut by a diaphragm. The advantage of a diaphragm compressor is the compressed air in the compression chamber does not come in contact with the piston and is lubricated. Therefore it can be kept without oil. Here are some examples:


Because flexibility is limited, the weak point of a diaphragm compressor is typically its diaphragm itself. Diaphragm compressors are used for example in the food industry or for filling scuba divers bottles.

The working principle is totally unique from the so-called rotary compressor, which is also called a vane compressor. A typical rotary compressor has a round chamber. Adjustable rotors with their center point on the drive shaft are linked to the chamber.

So when the pivot rotates, these rotors develop a chamber of different sizes. Air is compressed into the biggest chamber, then compressed and left in the tiniest chamber. An advantage here remains in pulsed free circulation in contrast to piston compressors. So an air tank might be optional. Additionally, these compressors are low noise and fairly insensitive to dirt.

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