There is an old adage which is also a law of physics; what goes in will eventually come out. This applies to compressor lubricant in oil-flooded rotary screw compressors. At a rate of 2 ppm carryover, an oil-flooded 100 hp compressor operating for one year (8000 hrs) will introduce over 4 gallons of lubricant into a compressed air system. Eventually, this lubricant will drop out.
Compressed air users are becoming increasingly intolerant of contamination in their systems, whether it is in a patient’s lungs, food and beverage products, pharmaceuticals, semiconductors, or any process that requires clean, dry air. Compressed air can also be dried and filtered to dry nitrogen specifications and used in applications where the inert quality of nitrogen is not required. This is typically known as “CDA” (clean dry air) in the electronics industry, but every industry can benefit by using it. CDA may mean different things in different industries in regards to dew point (how dry the air is), but all CDA systems have one thing in common, the air must be oil-free and that requires the use of oil-free air compressors. For industries that require compressed air to make their products, the higher the quality of the compressed air, the better the product and the lower the cost to produce it.
Most companies who have standardized to oil-free compressors started out using oil-flooded compressors. System contamination was not detected and accumulated gradually. In some cases this occurred within a year, in some almost five years until the inevitable occurred; contaminated product, production shut down and the cost to replace contaminated piping, filtration, dryers, receivers and compressors. In one case, the owner moved out of a facility entirely, installed oil-free compressors and lived with a six month interruption in production, a tremendous price to pay. Most major food manufacturers have tried using oil-flooded compressors at some point in their history, with disastrous results. Product recall because of compressor lubricant is a high price to pay in dollars and reputation!