Do you ever ask yourself and think about one thing is: “Why oil free air compressors more expensive than oil-injected one?”

When we request of 100% oil-free compressed air for business, we need an oil-free compressor. The basic principle of the oil-free screw compressor is similar with the oil-injected compressor, but there is no oil injected during compression process.

100% dry oil-free means that there is no oil for lubricating the rotors and for cooling the compressed air, elements and other parts inside compression room. Since no oil for sealing, the rotors need to be very Precision and have very small tolerances, the rotors don’t touch each other, but the air-gap need very small.

You may ask, if the rotors get too hot and grind to a stop during the operation, how to avoid it? DENAIR dry oil free air compressors divide it into 2 parts: 1 stage compression and 2 stage compression.

The first stage compresses the air into about 2.1 bar. The air is cooled down by the after cooler, and the second stage compresses the air into the end pressure which customer requested. The 2 stages work together to produce the required output pressure, special design make them could work in a perfect balance.

Now we described why the oil-free screw compressors are more expensive: because they have two compression stages, compared to one stage compression oil-injected compressors. Further more, the elements used in oil-free air compressors are more expensive than oil-injected type, since they are manufactured with much smaller clearances.