Achieving Proactive Maintenance Through Particle Counting

27 September 2022

AUTHORED BY: Reliability360


With the widespread use of plant-level particle counters, maintenance organizations are becoming more sophisticated and skilled in the management and control of oil cleanliness. This has led to the discovery of a host of new tactics and practices that involve combining the particle counter with other important onsite oil analysis tools and methods.


Contamination can be defined as any unwanted substance or energy that enters or contacts the oil. Contaminants can appear in many forms and can be highly destructive to oil, additives, and machine surfaces. It is often overlooked as a source of failure because its impact is usually slow and imperceptible, yet, given time, the damage is analogous to eating up the machine from the inside out. While it is not practical to attempt to eradicate contamination from in-service lubricants, control of contaminant levels within acceptable limits can be accomplished and is vitally important.

Contaminants such as particles, moisture, soot, heat, air, glycol, fuel, detergents, and process fluids are commonly found in industrial lubricants and hydraulic fluids. However, particle contamination is typically recognized as the most destructive to the oil and machine, which explains why the particle counter is the most widely used instrument in oil analysis today. Additionally, the central strategy to its success in reducing maintenance costs and increasing machine reliability is proactive maintenance.

Implementing a Proactive Maintenance Strategy

While the benefits of detecting abnormal machine wear or an aging lubricant condition (which can be achieved with oil analysis programs) are important, they should be regarded as low on the scale of importance when compared to the objective of failure avoidance. This is achieved by treating the causes of failure, not simply the symptoms, and is additionally the foundation of the popular practice known as proactive maintenance. In fact, the only effective way to obtain simple solutions to complex machine maintenance problems is through proactive maintenance.

Whenever a proactive maintenance strategy is applied, three steps are necessary to ensure its benefits are achieved. Because proactive maintenance, by definition, involves continuous monitoring and controlling of machine failure root causes, the first step is to set a target, or standard, associated with each root cause. In oil analysis, root causes of greatest importance relate to fluid contamination (particles, moisture, heat, coolant, etc.).

However, the process of defining precise and challenging targets, such as high cleanliness, is only the first step. Controlling the fluid’s conditions within these targets must then be achieved and sustained. This is the second step, and it often includes an audit of how the fluids became contaminated and then systematically eliminates these entry points. Better filtration and the use of separators are often required.

The third step is the vital action element of providing the feedback loop of an oil analysis program. When exceptions occur, such as over-target results, remedial actions can then be immediately commissioned. Using the proactive maintenance strategy, contamination control becomes a disciplined activity of monitoring and controlling high fluid cleanliness, not a crude activity of trending dirt levels.

Finally, when the life extension benefits of proactive maintenance are flanked by the early warning benefits of predictive maintenance, the result is a comprehensive condition-based maintenance program. While proactive maintenance stresses root cause control, predictive maintenance targets the detection of incipient failure of both the fluid’s properties and certain machine components. It is this unique, early detection of machine faults and abnormal wear that is frequently referred to in the maintenance field as the exclusive domain of oil analysis.

Managing Particle Contamination

There is no single property of lubricating oil that challenges the reliability of machinery more than suspended particles. It would be no exaggeration to refer to suspended particles as a microscopic wrecking crew. Small particles can ride in oil almost indefinitely, and because they are not as easily friable or crumbled as their larger brothers, the destruction can be continuous.

Many studies have proven with convincing evidence that greater damage is associated with small particles. Still, most maintenance professionals have misconceptions about the size of particles and the associated harm caused.

These misconceptions relate to the definition people generally apply to what is clean oil versus dirty oil. And it is this definition that influences the setting of appropriate target cleanliness levels for lubricating oils and hydraulic fluids. The process is not unlike a black box circuit. If a change to the output is necessary for longer and more reliable machine life, then there must be a change to the input (a lifestyle change; for example, improved cleanliness). For instance, it is not the monitoring of cholesterol that saves humans from heart disease – it is the actions we take to lower cholesterol. Therefore, the best target cleanliness level is one that shows a marked improvement from historic levels.

To help with this impression, facilities have begun turning to lubricant monitoring particle counters to take the guesswork out of analyzing and gathering information from an oil analysis. As one of the only true optical particle counting technologies available, the Atten2 online particle counter features high-definition lenses, LED lighting, a camera instead of a traditional laser, and a digital processor to accurately identify and count particles, helping to determine the exact type of wear occurring in your equipment.

With Atten2 utilizing a camera to capture the particle images, the system is not only able to count the particles, but it can identify and separate out the bubbles to ensure the count is as accurate as possible. This and other product enhancements have helped make this one of the most portable, affordable, and fastest particle counting options for many facilities, especially when compared to traditional lab oil analysis methods.

There are many expensive ways to achieve clean oil, but experience has taught the wisdom of contaminant exclusion – treating the cause and not just the symptom. By effectively excluding the entry of contaminants and promptly removing contaminants upon entry, new cleanliness targets are frequently achieved.