What Every Compressor User Needs to Know but their Supplier Wishes They Didn’t

If your company uses oil-injected rotary screw air compressors, you’ve undoubtedly heard your supplier talk about the major impact the compressor’s oil (coolant, compressor fluid) has on compressor performance and reliability. At the same time, you probably heard them stress the “need” to regularly replace your oil at their prescribed interval. Unfortunately, like many of the myths perpetuated in the compressor industry over the decades, only about half of what you hear is true and there’s a lot more they’re not telling you that they don’t want you to know.

For example, yes, the performance of your rotary screw compressors’ oil is absolutely a leading factor affecting its performance, reliability and cost of maintenance, and definitely deserves special consideration and treatment. But, no, your compressors’ oil does not “need” to be regularly replaced at any specified time interval, especially those created by the OEMs’ marketing departments. “Time-based” oil changes, like those still promoted by the compressor OEMs, are obsolete, wasteful, and given today’s technologies, should be considered maintenance malpractice. Perpetuated by the compressor companies with the goal of selling more oil, time-based oil replacement totally ignores one thing that’s really important – the oil’s actual condition. The OEMs’ time-based oil changes dictate that even oil in good condition gets replaced whether needed or not, and it ignores the root causes responsible for oil failure and replacement, like additive depletion.

So to help set the record straight and dispel some of the myths and misinformation that’s needlessly costing you time and money, below are some important truths every compressor user needs to know about rotary screw compressor oils and their additives, that they won’t hear from their compressor supplier.

Additives are Vital Ingredients Used in All Compressor Oils

Regardless of whether the oil is formulated from mineral or synthetic base stocks, all rotary screw compressor fluids rely on a combination of additives to improve their performance and service life. Special chemical compounds are added to the base oil to enhance its good properties, suppress its undesirable properties, and impart new properties specifically needed for the application.

Compared to most other types of rotating equipment, oil-injected screw compressors present severe challenges for the oil. These compressors have a unique “forced-contamination” design that creates an extreme oxygen and contaminant rich environment that makes them one of the toughest oil applications there is. In addition to the oil’s basic functions as a lubricant, coolant and sealant, its most important and challenging functions are resisting oxidation, acid production and protecting vital compressor internals against corrosion, wear, deposits and fouling – the root causes responsible for most preventative maintenance and repairs. Without special additives, the oil’s base stocks wouldn’t stand a chance

Additives Improve Oil Performance and Service Life

Two of the most important additives used in rotary screw compressor fluids are its oxidation and corrosion inhibitors. Given the compressor’s unique design, these additives have a particularly profound impact on oil performance and compressor reliability. Without a healthy dose of these additives, oxidation rates, acid production and oil degradation would accelerate unimpeded, and the oil’s ability to protect compressor internals and deliver long life would only be a fraction of a fully formulated oil.

Compressor OEMs & Oil Suppliers Limit Their Oil’s Additive Levels

With any oil formulation there is a direct relationship between its additive levels, oxidation resistance, corrosion protection and useful life. In simplistic terms, for any given base oil and additive package, the higher the dose of additives used, the better it resists oxidation and degradation, the better it protects compressor internals, the longer its life, the lower the users oil consumption, maintenance frequency, downtime and costs.

The compressor OEMs know all this, however, instead of optimizing oil additive levels for their customers’ benefit, they choose to limit their additive levels and artificially limit oil life for their own benefit. They could easily formulate their oils with a more robust additive package to provide increased protection and longer life, but they would rather sell more oil at their customers’ expense.

Additives Constantly Deplete and Performance Suffers

While in service, compressor oils and additives are under constant attack by the air, humidity, heat and other harmful contaminants that are continuously being ingested by the compressor and pumped into the oil. Inside the compressor a destructive series of chemical reactions is constantly taking place with the oil’s additives providing the first line of defense. With every CFM of air that passes through the oil, its oxidation and corrosion inhibiting additives are called into action where they are sacrificed for the good of the oil and naturally deplete. As additives deplete and oil defenses weaken, oxidation and acid production accelerate, and the oil’s protective additives deplete faster and faster. Like a freight train barreling downhill, this chain reaction of oxidation, additive depletion, acid production and oil degradation continuously gathers speed racing towards catastrophic failure or premature replacement.

Additives are Easily Replenished to Restore Protection and Increase Life

Fortunately, there are easy ways to dramatically slow this oxidation – degradation cycle. Preblended additive concentrates containing the same oxidation and corrosion inhibitors used in new oils are readily available for routine replenishment. Not surprisingly, you won’t find them offered from the traditional compressor oil suppliers. That’s because they know that by periodically adding small doses of additives users can easily replenish additives to healthy new oil levels, restore protection, and dramatically increase oil life causing their oil sales to plummet. When combined with proactive contaminant controls, additive replenishment has been shown to increase oil life up to 10 times, and virtually eliminate the OEMs’ obsolete, wasteful and expensive time-based oil changes.

Fluid Metrics is the industry leader in compressor oil formulation, contaminant control and fluid conditioning technologies. Contact us today and let us show you how easy it is to replenish your oil’s additives, improve your compressors’ reliability and save you time and money.