Contamination in Rotary Screw Compressors

Rotary screw compressor oil is required to operate in conditions that are foreign to most lubricating products.  All oil lubricated rotary screw compressors are designed to draw in large amounts of air and force this air into an oil chamber.  Oil therefore must be able to withstand the oxidative properties of air, as well as the churning of the air oil mixture in the compression chamber.  This extreme oil aeration is unique, and requires additives or synthetic properties that are far above normal lubricant requirements.  Thus, an air compressor is essentially a reactor, which ingests air, pollutants and water vapor, and combines them with oil, heat and pressure to provide you with compressed air.

Not only is air introduced that is a chemical reactant, compressor oil is subjected to extreme heats that are catalysts to these chemical reactions.  Heat is a byproduct of not only the bearings and gears, but also the heat of compression, as the air is pressurized from atmospheric pressure through the rotary elements.  These elevated temperatures put further demands on your lubricants.

Additionally, the air that is drawn into a rotary screw compressor contains water vapor, dust, pollutants and potentially chemical gases, that all can contribute to breaking down the oil.  All of these various things are unique to a compressed air system, and must be managed by using a recommended quality lubricant, to guarantee that your compressor will operate properly.