Machinery Lubrication magazine published by Noria Corporation
Issue link: http://www.e-digitaleditions.com/i/388231
www.machinerylubrication.com | September - October 2014 | 29 Your lubricant's additives are being consumed rather than progressively exhibiting deteriorating performance. additive depletion and lubricant failure is to establish persistent oil analysis. Histor- ical information on the lubricant's typical useful life in the given circumstances will be helpful as well. Although trending addi- tive depletion requires enhanced oil analysis methods and skills, it is now being done with increasing effectiveness. Be sure to monitor each additive in a lubricant, as it's possible to lose one additive well before another. For example, it does no good to have a lubricant with sufficient antioxidants remaining if the anti-wear additive is entirely depleted. In this case, your oil will permit accelerated wear even while anti oxidation remains stable. For lubricants in gasoline or diesel engines, the hours of operation along with the known duty cycle are often the primary gauges for determining the lubricant's remaining useful life (RUL). The engine manufacturer will provide general esti- mates of the oil change interval, because after a certain point in the lubricant's life, one of the additives likely will become depleted. Although the lubricant may appear healthy (just like the car operating on a single gallon of gas), it's only a matter of time before the effects of the distressed or non-existent additive system become detrimental to the engine. Even with condition-based oil changes, such as for turbine oil in high-speed appli- cations, it's important to conduct tests to determine the remaining useful life of each additive. Certain tests can give you an indication of residual additives and oxidation stability. The main lesson here is that your lubri- cant's additives are being consumed rather than progressively exhibiting deteriorating performance. Many people have the misconception that lubricants fail in a linear fashion. Instead, performance can drop off suddenly and catastrophically, just like a car sputtering on its last drop of gas. If you are actively monitoring your lubricant's RUL, you should be aware of the individual additive depletion probabil- ities and be able to predict the end of their useful life. About the Author Bennett Fitch is a technical consultant with Noria Corporation. He is a mechanical engi- neer who holds a Machine Lubricant Analyst (ML A) Level III certification and a Machine Lubrication Technician (MLT) Level II certi- fication through the International Council for Machinery Lubrication (ICML). Contact Bennett at bfitch@noria.com. ML o i l A n a l y s i s 36 P E R C E N T of lubrication professionals do not use oil analysis to monitor additive health, according to a recent survey at MachineryLubrication.com