Why don't oil-free compressors use lubricating oil?

What is an oil-free air compressor? Do you want to use air compressor oil?

The so-called "oil-free" means that the gas is not in contact with the oil during the compression process and does not use air compressor oil.

In the oil-injected screw compressor, a large amount of lubricating oil is injected into the compressed gas medium, which plays the role of lubrication, sealing, cooling and noise reduction. The oil-injected screw compressor does not have synchronous gears, and the male rotor directly drives the female The rotor rotates. In addition to reducing the exhaust temperature, the lubricating oil also provides lubrication for friction pairs such as bearings, mechanical seals, and slide valves.

The oil-free air compressor uses water lubrication, so the final gas does not contain oil.