There’s no doubt that equipment reliability is critical. Whether it’s a hydraulic press in a manufacturing plant, or an off road loader in a mine, downtime is costly. Oil contamination, though one of the main causes of premature equipment failure and downtime, is often overlooked. Interestingly, in many cases the greatest cost associated with equipment failure isn’t the component replacement cost, but the cost associated with production downtime. Add to that the cost of the lubricants themselves, whose life is significantly diminished by contamination, and the added costs associated with disposal or recycling them. Neglecting oil contamination can bring an operation to its knees.
There are two ways to deal with contamination: prevent it or remove it. While in most cases it may be important to do both, and of course to also have in place a comprehensive oil sampling and analysis program to monitor the lubricants’ condition and overall machine health, there is no doubt that removing contaminants is significantly more costly than preventing them to begin with. As nearly all gearboxes, reservoirs and storage tanks are designed to breathe, allowing only clean, dry air to enter the system is one of the best measures to prevent contamination. Simply replacing standard breather/filler caps with a desiccant breather immediately prevents moisture and moves particle filtration from 40 micron to 2 micron.
U.S. Lubricants has assembled a comprehensive range of solutions to help you prevent oil contamination, as well as to remove it. We can also assist you in developing and implementing a Comprehensive Precision Lubrication™ program, as well as to manage it on site. We can provide you the tools to monitor oil quality and help you design and implement a proper oil sampling process. U.S. Lubricants' OilChek® oil analysis services can provide you with ongoing analyses and an early warning mechanism that could help you avoid costly equipment failures and downtime, and help you extend the life of your machinery.
The two main sources of contamination for your lubricants are dirt/particles and moisture. Various studies have pointed out that 70% of component replacements or ‘loss of usefulness’ is due to surface degradation. In hydraulic and lubricating systems, 20% of these replacements result from corrosion, and the remaining 50% results from mechanical wear.
Most particles start off as dirt that becomes airborne. It finds its way into lubricant and fuel reservoirs, and is later transported to bearings, bushings, seals, valves, and other machine components. There they become key ingredients in abrasion, erosion, and fatigue failures. Particles that manage to enter your lubrication system can cause tremendous damage as they essentially amplify and accelerate the contamination by generating new contaminants (by abrading and wearing out critical components in your equipment that in turn create more contaminants, and so on). The contaminants also cause lubricant degradation, shortening the life of the lubricant and decreasing its ability to lubricate.
Some type and quantity of internal particulate contamination is inevitable and can point to a problem with the machine or a component. Internal particulate contamination includes any particles that contaminate the oil once it has been added to the closed lubrication system - wear particles, seal material, etc. When you have reasonable confidence that external particulate contamination is under control, oil analysis or condition monitoring equipment that identifies a high particle count could be an early warning signal for a developing abnormal wear situation.
Particles, especially catalytic metal particles like copper, iron and lead, increase the oxidation rate and strip the oil of its anti-wear and extreme pressure additives, rust inhibitors and dispersants. Numerous small particles in stable suspension can cause the oil's viscosity to increase, compromising its pumpability and may also promote foaming. Finally, as mentioned earlier, these particles are also abrasive. And as with all particulate contaminants, once in the oil, they accelerate the wear rate dramatically, because abrasive wear can cause a chain reaction in lubricated machinery.
With machine clearances nowadays measured in thousandths of an inch, it doesn't take much contamination to affect bearings and other sensitive components. Even particles that are 10 micron or smaller can disrupt the lubricant film and cause a great amount of wear.
There are many likely sources for water contamination, primarily including leaks (heat exchanger, seals), condensation associated with high airborne humidity, inadequate reservoir covers, temperature reduction (causing dissolved water to turn into free water), and equipment wash-down.
Once water has entered the lubricant, it can exist in one or more of the following forms; dissolved, emulsified, or free water.
Dissolved water contains water molecules that are dispersed one-by-one through the air in contact with, or within the lubricant. This form of water is invisible to the naked eye.
Emulsified water contains microscopic pockets of water that are dispersed in stable suspension in the oil. As the oil ages this area of water will expand, causing the lubricant to look cloudy.
Free water is the phase separation of emulsified water. Free water, when mixed with the lubricant, readily settles to the bottom of the equipment.