Dintsu Engineering Technologies (Pty) Ltd
Autorised Distributor of Ingersoll Rand

How do oil-free air compressors work?

Oil-free compressors are a great option when you need a lightweight, low maintenance air compressor. They aren’t suited for heavy-duty jobs or commercial and industrial use. They are also convenient in places where there is a need to avoid having the consequence of oil contamination in the air. Oil-free air compressors can provide a higher quality of compressed air. This is how oil-free compressors work.

Oil-free compressors draw in air through their unloader air valve then pass it through an inlet air filter. This filter is important in ensuring to maintain the quality of the air and to minimise the damage that dirt and dust may cause to the internal components of the compressor.

The unloader valve opens up to let the compressor pump air into the chamber. This is where air beings to be compressed. The compressor starts to produce heat because there is no oil flowing through the compressor to cool and lubricate it.

After the air is compressed, pistons push the air through the spiral, where the air is cooled. This element cools the air for it to be further compressed. This is highly important because the heat produced can damage the compressor. In a rotary screw compressor oil-free just means that the rotors that reduce the volume of the air aren’t lubricated with oil. This is why they can’t run for long periods as oil-based compressors can.

The cooled air is then returned to the main chamber to be further compressed. This does mean that the air will become very hot again so it will require cooling once more. As the fully compressed air flows it will pass through to the aftercooler and a check valve to prevent any backflow. The air can finally be stored or sent out for use.  

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