Is Oil analysis still relevant today?

With the many advancements in Artificial Intelligence, Machine Learning and the advent of countless different sensors on the market, the question arises, “Is Oil Analysis still relevant today?”. Granted that these advancements have significantly transformed the industry, we need to recognize that they are here to help evolve what we already do and not necessary replace it.

These advancements build upon the foundations of the techniques of oil analysis. With artificial intelligence and machine learning, we can train models to interpret oil analysis data and trigger alerts accordingly but there should always be a human present to overview these. In the real world, not every situation has occurred or been recorded yet hence the models do not have that particular data to learn from nor can they make decisions about it since it simply doesn’t exist in their “brain”.

Humans can “think outside the box” and formulate patterns or trends which may not be triggered by the models simply because these models have not been taught these patterns. Hence it is important to always have a human in the loop and not rely solely on these models especially when million-dollar decisions can be negatively initiated with the wrong interpretations.

Lately, sensors have gained more traction and a wider adoption as they can be integrated into warning systems to alert users to potential deviation from known characteristics of the oil. However, as noted above, sensors rely on data sets to compare the information and on some form of capacitance which must be converted into a signal before it can be interpreted.

With lab equipment performing the actual tests, there is a higher rate of accuracy plus the added advantage of having humans review the results for discrepancies before sending off the report. While sensors can be the first warning system for some users, lab equipment should be utilized for those more precise tests which require a higher level of accuracy.

In essence, oil analysis remains very relevant today. However, it has significantly evolved over the last few decades. Today, oil analysis can achieve a higher efficiency level with the integration of the advancements in technology (AI, machine learning and sensors) and other available monitoring technologies. Together, these should all be used to create a greater impact on improving the reliability of the machines.

Find the full article here on Engineering Maintenance Solutions Magazine.

Oil Properties / Used Oil Analysis

Oil analysis vs Other technologies

Just as oil analysis is similar to blood testing, we can think of our bodies as a critical machine with various components which need to be monitored. If we get a fractured bone, a blood test will not help us to assess if the bone is broken or can be repaired. In this case, we may need an x-ray. Similarly, with machines, there are various types of tests to determine different aspects to be monitored.

Typically, oil analysis can provide the operator with insight into whether there has been any internal damage to the equipment in the form of wear particles which can be quantified. As with most condition monitoring methods, being able to trend the patterns over time helps the operators to identify if wear is occurring at an increased rate or whether the oil is degrading.

On the other hand, other technologies such as vibration analysis or ultrasound analysis or even thermography are not able to detect the presence of molecules. These other types of analyses focus on alignment, or other mechanical issues as they occur and can trend them over time. However, oil analysis can accurately detect the presence or absence of contaminants or additive packages which could affect the health of the oil and by extension that of the machine.

Oil analysis should not be used as the only technology in your condition monitoring artillery. Other technologies can be used alongside oil analysis to provide the user with a more comprehensive overview of the health of the asset. For instance, if the oil analysis discovered high wear, the next step would be to identify where the wear was coming from. Perhaps in this case, one of the other technologies could identify a misalignment or other mechanical issue which could be the source of this wear. Thus, these technologies should be used to work together to achieve better reliability for their asset owners.

Find the full article here on Engineering Maintenance Solutions Magazine.

Oil Properties / Used Oil Analysis

Why oil analysis?

The P-F curve is one that is used throughout reliability to demonstrate the point at which a component is expected to have a functional failure. There are many variations of the PF curve, and different monitoring technologies can be placed in specific orders accordingly. However, it remains dominant that oil analysis is among the top three techniques used for early detection of failure.

Oil analysis can be used to detect the presence of contaminants, metals and other molecules at a microscopic level and quantify these appropriately. Most OEMs (Original Equipment Manufacturers) publish their acceptable standards for various tests (usually standardized tests by some accredited body such as ASTM) and have these available to laboratories around the world. When an oil analysis test is performed (as per the stipulated standards), the lab will compare the actual values to the expected values (from the OEM) and then provide some guidance to the user on possible steps forward.

Every lab will have a specific format for reporting the results of your oil analysis (similar to the labs for reporting on blood samples). Typically, the actual value is shown and then there may be an expected range for the various characteristics or just an indication of whether the actual value falls outside of the range (on the higher or lower end of the scale).

Bureau Veritas, 2017, gives an example of a report and all of the variables involved here:

BV_Understanding-An-Oil-Analysis-Report_FINAL_11_8_2017

While this is their reporting standard, other labs will have a different format, but the tests will all conform to the same internationally recognized standard. As such, if oil is tested in the United States (as per a particular standard) and then tested in Italy (as per the same standard) then there can be some comparisons of these results. However, one must also be aware of the types of instruments being used and their calibration as this can account for slight differences in test results. As such, oil analysis provides a global standard for which equipment performance can be compared across regions.

Find the full article here on Engineering Maintenance Solutions Magazine.

Oil Properties / Used Oil Analysis

What is oil analysis?

For those not familiar with oil analysis, it can be likened to performing blood tests for the human body. Oil in our machines is often compared to the blood in our bodies. Blood circulates throughout the body taking important blood cells with food and oxygen in it to the various organs, similarly oils follow this behaviour. However, oils transport additives which provide varying functions including reducing wear or friction or even preventing corrosion or oxidation to name a few.

When performing a blood test, we can test for a few things; the overall condition of the organs or we can test for specific things such as the presence of bad cholesterol. With oils, we do a very similar practice where we can test for the overall health of the machine or pinpoint exact components and look for distinct changes which are reflected in the characteristics of the oil.

Basically, oil analysis can help you to determine the condition of your oil (if it is degrading or if the additives have depleted such that it no longer protects the equipment) and the health of your asset as the oil can reflect if there is wear occurring in the components. As such, it can provide very useful information to help operators and maintenance personnel to plan effectively for any type of maintenance to be done on the components.

Find the full article here on Engineering Maintenance Solutions Magazine.

Industrial / Strategic Tips

ISO 4406 rating

Is the ISO 4406 rating important?

Yes, it is very important!

The ISO 4406 rating tells us the cleanliness level of our lubricant. It tells us the number of particles that can pass through a 4, 6 and 14 micron rating.

However, the value on the ISO rating does not represent the number of particles. On the contrary, it represents the range in which the number of particles can lie.

One key point to remember is that the rating will always change from the time that the sample was taken to the date that the results were processed.

Therefore, it is a good idea to use the sample result as a guide as estimate a bit higher for the real value of your lubricant.

Check out our article which goes into more detail about ISO 4406.

Matt Spurlock CLS, CMRP, MLE explains further about redefining the ISO code in his article entitled; "A Twist on Particle Evaluation: Redefining the ISO Cleanliness Code".

Used Oil Analysis

Used Oil Analysis Tips

“When should an oil sample really be taken?”

In used oil analysis, oil samples can be taken at any time, but one should always consider the insight that they are trying to gain before testing the sample. This is crucial in deciding the type of tests and the intervals at which they should be performed.

For instance, if we are testing the quality of the oil or we want to compare a fresh batch to a used one, then we can take a sample directly from the drum.

If we are trying to decide the rate at which the additives are being depleted or wear being accumulated then we can take a sample at different operating hours to trend the data. This method can work if we are trying to determine the most appropriate run time for a lubricant in particular conditions.

However, if we are trying to track the health of the components on a regular basis as part of our PM program then taking a sample at the end of the scheduled maintenance interval is desired.

Taking an oil sample from a component is like performing a blood test by the doctor. It helps us to understand what’s really happening. It can show us if there is excessive wear, contamination or lubricant degradation which allows us to identify its “health”. However, the correct tests need to be carried out to determine these conditions.

There must be a reason behind taking the oil sample, not just a random act. When trying to establish a trend regarding a particular aspect of the oil, this should guide your choice of tests otherwise we can end up paying for tests that do not add value.

Always ensure sound reasoning behind testing rather than just checking the box!

While taking an oil sample at the end of the scheduled operating hours is very convenient, is it truly efficient?

When a piece of equipment is scheduled for maintenance, it is usually taken out of service for a couple of hours to perform the assigned
maintenance tasks.

However, if an oil sample is taken a couple days in advance of the scheduled maintenance, then when the results return the maintenance team can be on the lookout for issues highlighted by the results.

For instance, if the value for iron was significant or rising then they can perform inspections for areas which may cause this type of wear and address this challenge while the equipment is offline.

The graphic on the side can be used as a quick guide to determining when to take a sample.

Remember to always evaluate the reason behind establishing the sampling frequency before scheduling sampling.

Lubricant Degradation

Microdieseling

What is Microdieseling?

Microdieseling is also called Compressive Heating and is a form of pressure induced thermal degradation.

The oil goes through 4 stages in this degradation process:

1. There is a transition of entrained air from a low pressure to a high pressure zone

2. This produces localized temperatures in excess of 1000°C

3. The Bubble interface becomes carbonized

4. The oil darkens rapidly and produces carbon deposits due to oxidation

The conditions required for microdieseling can be either:

Low flashpoint with LOW implosion pressure
Low flashpoint with HIGH implosion pressure

For a low flashpoint with a HIGH implosion pressure, this constitutes to ignition products of incomplete combustion such as soots, tars and sludge

However, for a low flashpoint with a LOW implosion pressure, adiabatic compressive thermal heating degradation occurs to produce varnish from carbon insolubles such as coke, tars and resin.

Lubricant Degradation

Electrostatic Spark Discharge

What is Electrostatic Spark Discharge?

Electrostatic Spark Discharge is real and extremely common for turbine users!

Static electricity at a molecular level is generated when dry oil passes through tight clearances.

It is believed that the static electricity can build up to a point whereby it produces a spark.

There are three stages of ESD.

1. Static Electricity builds up to produce a spark – Temperatures exceed 10,000°C and the lubricant begins to degrade significantly.

2. Free radicals form – These contribute to the polymerisation of the lubricant

3. Uncontrolled polymerisation – Varnish and sludge produced (some may remain in solution or deposit on surfaces) which can also result in elevated fluid degradation and the presence of insoluble materials.

Storage & Handling of Lubricants

Colour Coding

What is the importance of Colour Coding?

Quite often when we are correcting or helping companies set up their lubrication storage areas, we get asked a lot of questions regarding colour coding.

Ideally, the concept of colour coding is to allow field personnel to easily identify and associate particular lubricants with their applications.

However, like most things in reliability, this can be customized to suit your organization. There are no hard and fast rules of using only yellow to represent hydraulic oils.

What if we had someone that was colour blind?

Usually, when we start colour coding lubricant storage containers, we include symbols and actual names of the lubricant. This helps to assist personnel in having a 3 point verification system.

First they can verify the colour, then the symbol and of course the name of the lubricant.

Names are crucial! Especially for varying viscosities (such as gear or hydraulic oils). For instance all gear oil would have the same colour and symbol but you wouldn’t want to put an ISO 100 gear oil in a gearbox suited for ISO 680.

Used Oil Analysis

ISO 4406

A lot of people get confused when reading the ISO 4406 rating. The rating specifies a range of the number of particles of certain sizes that can pass through 3 particular sized filters namely; 4micron, 6 micron and 14 micron filters respectively.

For instance; a rating of 13/11/8 indicates:

13 represents 4000-6000 particles over the size of 4um
11 represents a range of 1000-2000 particles over the size of 6um and
8 represents a range of 130-250 particles over the size of 14um.

These values are actually the number of particles per milliliter. It does not mean that you have 13, 11 or 18 particles only in your oil, it's much more than that!

There are different ratings for different levels of cleanliness.

If your numbers are really high (25/22/19) then there’s definitely a high level of contamination!

Different components have different ISO cleanliness ratings. For instance, a roller bearing has a higher cleanliness target than a Variable Vane pump.

Understanding the ISO 4406 codes are crucial for determining the steps needed in “cleaning up” your system lubricants.

However, when we test for the cleanliness of an oil, there are a couple things that we need to consider:

When testing, we have exposed the oil to the elements (highly dependent on the method of sampling)
Results are not instantaneous (even with an onsite lab, there will be a timeframe between collecting the sample and processing it)

Since there are lag times involved, the value that is reported for the ISO4406 rating is never really truly representative of the oil. As such, when analysing the results of this test, it is important to consider that the actual value may potentially be higher than reported.

Matt Spurlock CLS, CMRP, MLE explains further about redefining the ISO code in his article entitled; "A Twist on Particle Evaluation: Redefining the ISO Cleanliness Code".

Tagged: oil analysis

What is Microdieseling?

What is Electrostatic Spark Discharge?

What is the importance of Colour Coding?