Book Chapter,
Tribology Data Handbook, an Excellent Friction, Lubrication, and wear Resource.
Edited by E. Richard Booser.

Whenever a proactive maintenance strategy is applied, three steps are necessary to insure that its benefits are achieved. Since proactive maintenance, by definition, involves continuous monitoring and controlling of machine failure root causes, the first step is simply 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.) and additive degradation. However, the process of defining precise and challenging targets (e.g., high cleanliness) is only the first step. Control of the fluid’s conditions within these targets must then be achieved and sustained. This is the second step and often includes an audit of how fluids become contaminated and then systematically eliminating these entry points. Often better filtration and the use of separators are required.

The third step is the vital action element of providing the feedback loop of an oil analysis program. When exceptions occur (e.g., 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. a comprehensive condition-based maintenance program results. While proactive maintenance stresses root cause control. predictive maintenance targets the detection of incipient failure of both the fluid’s properties and machine components like bearings and gears. Following the oil sampling procedures. selection of appropriate sample testing procedures, and interpretation of test results outlined in this section. immediate corrective action can then be directed to effectively avoid failure chain reactions and further self-destruction.

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Every industrial organization has experienced the consequences of shoddy maintenance: contract penalties, junked parts, injuries, catastrophic damage, ballooning costs, missed shipping dates, irate customers, and sickly quarterly financial reports. Today, machinery and equipment can be maintained to achieve useful operating lives many times those attainable just a few years ago. For oil lubricated machinery, the opportunities surround what is commonly referred to as proactive maintenance.

Carefully monitoring and controlling the conditions of the oil (nurturing) can systematically eliminate many of the root causes of failure. Case studies of highly successful organizations show that oil analysis plays a central role in this nurturing activity. For oil analysis to succeed, the user organization must first define the goals of the effort.

Some people view oil analysis as a tool to help them time oil changes. Others view it in terms of its fault detection ability. Still others apply it to a strategy for contamination control and filter performance monitoring. In fact, when a program is well designed and implemented, oil analysis can do all of these things and more. The key is defining what the goals will be and designing a program that will effectively meet them. One might refer to it as a ready-aim-fire strategy. The ready has to do with education on the subject of oil analysis and the development of the program goals. The aim uses the knowledge from the education to design a program that effectively meets the goals. The fire executes the plan and finetunes it through continuous improvement.

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Historically, water contaminated oil has been said to exist in two states:

• Dissolved water (bound molecularly in the matrix of the oil)
• Free water (not molecularly bound)

In the last 30 years or so, most of the literature, including Noria’s publications, refer to water as having three states. Free water has been redefined as being water that, by force of gravity, will phase out of the oil. This means it will separate below (most common) or above the oil phase depending on oil density.

The new third state is emulsified water. Water that is held tightly in micro-globules in the oil is no longer referred to as free water. Instead, it has been more accurately referred to as emulsified water, or a “micro-emulsion”.

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Book Chapter. Automotive Lubricants and Testing. Edited by George Totten and Simon Tung

Most oil analysis performed in North America is done on diesel engine crankcase oils, primarily for large fleets in the transportation and off-road equipment industries. Ranking second would be the analysis of lubricants used in stationary industrial machinery including compressors, turbines, gearing, bearing lubes, and hydraulics. Far down the list is engine oil analysis performed on crankcase lubes from automotive fleets or privately owned cars and trucks.

Although there are a few isolated exceptions, condition monitoring of passenger car motor oils (PCMOs) has not yet emerged as a strong market. There are several understandable reasons for this. One is the fact that most car owners are not interested in paying a premium to extend engine life. Most car owners seem to be satisfied with the current engine life expectancy. This is evidenced by the fact that less than 10 % of PCMOs in use are synthetic formulations despite their widely promoted benefits.

Unlike commercial and industrial applications, in which machine owners often run equipment to their end of useful life, car owners are more commonly enticed to sell earlier for newer models. After all, why invest in engine life extension when the benefit of the investment would only be gained by the next owner of the vehicle?

Sampling is another impediment. Automobiles are not fitted with convenient oil sampling valves, nor are these valves easy to retrofit on engines. The only practical alternative is to obtain a sample from the dipstick port by drop-tube vacuum sampling or from the oil pan drain port. Neither of these locations is suitable for obtaining a representative sample.

The other factor is the cost and turnaround time of getting the data. Although laboratory automation has increasingly enabled basic tests to be performed quickly and with minimal cost of labor, routine oil analysis is still expensive for personal car owners. Some instruments are actually an integration of several conventional oil analysis sensors and often include viscometry, molecular spectroscopy, and atomic spectroscopy, typically with no needed glassware or sample preparation steps. So too, many new onboard sensors have been introduced that monitor key oil properties in real time. They displace the need for oil sampling and can alert the car owner to the optimal timing of an oil change or the presence of aberrant oil properties and wear metals.

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It takes only a small amount of water (less than 500 ppm) to substantially shorten the service life of rolling element bearings. There is a vast amount of research that supports this. Being a career-long crusader of clean and dry oil, I will certainly not argue the contrary. In fact, water’s destructive effects on bearings can easily reach or exceed that of particle contamination, depending on the conditions.

My theme for this column, therefore, is not about whether water imparts harm but rather how it does. Knowing how water attacks and causes damage helps in setting important dryness targets and also aids failure investigations post mortem. Further, when water contamination is unavoidable, understanding these water-induced failure modes can be valuable in the optimum selection of lubricants, bearings and seals for defensive purposes.

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Every industrial organization has experienced the consequences of shoddy maintenance: contract penalties, junked parts, injuries, catastrophic damage, ballooning costs, missed shipping dates, irate customers, and sickly quarterly financial reports. Gone are the days when a machine had a predictable service life, after which it was replaced, continuing the cycle. Today, machinery and equipment can be maintained to achieve useful operating lives many times those attainable just a few years ago. For oil lubricated machinery there are many opportunities in what is commonly referred to as proactive maintenance.

By carefully monitoring and controlling the conditions of the oil (nurturing), many of the root causes of failure are systematically eliminated. Case studies of highly successful organizations show that oil analysis plays an important, central role in this nurturing activity. But first, in order for oil analysis to succeed the user organization must define what the goals will be.

Some people see oil analysis as a tool to help them time oil changes. Others view it in terms of its fault detection ability. Still, others apply it to a strategy relating to contamination control and filter performance monitoring. In fact, when a program is well designed and implemented, oil analysis can do all of these things and more. The key is defining what the goals will be and designing a program that will effectively meet them. One might refer to it as a ready-aim-fire strategy. The ready has to do with education on the subject of oil analysis and the development of the program goals. The aim uses the knowledge from the education to design a program that effectively meets the goals. The fire executes the plan and fine-tunes through continuous improvement.

The post Successful Oil Analysis Practices in the Industrial Plant appeared first on Tesibis.

The majority of wear related failures occur as the direct result of particulate contamination. A recent article published in Lubrication Engineering magazine concludes that more than 82% of wear related losses are contaminant induced. And, the largest portion of this is abrasive wear; the direct result of particles wedged between rolling and sliding surfaces.

According to work done by SKF, bearings can have “infinite life” when the influence of particle contamination is eliminated. In some cases more than a 75-times life extension can be achieved by maintaining exceedingly clean lubricating fluids. It is also worth noting that the penalty associated with a contaminated lubricant is identical to that of using a lubricant with just 25% of the recommended viscosity.

There are few forms of internal machine failure that don’t release particles into the lubricant; detecting increases in particle contamination can be extremely important. Figure 1 lists some of the failure types detectable using contaminant monitoring.

As a predictive maintenance technique, abnormal particle trends are the early symptoms of several non-particle induced conditions. Once the abnormal trends are recognized, a more precise assessment of lubricant condition or machine malfunction can be pursued.

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