Turning Air Measurements Into Reliability Insight

The Smart Bubble System, developed by Evamo, allows users to gain deeper insight into the behavior of air in their oil. It turns a general volume-based quantification into actionable metrics to improve your system’s reliability and performance. The SBS captures the following metrics:

Bubble diameter
Air content in your system
Bubble count
Bubble size-distribution
Oil-Air contact surface
Transient bubble events

Turning Air Measurements Into Reliability Insight

These metrics are directly related to what users see in the field. As such, it closes a gap that many users often experience when relating lab results to field integrations. Users can also trend whether the number of smaller bubbles increased, whether large bubbles began to form in their system, or whether there were transient spikes due to particular conditions in temperature, load, speed, or even return-flow conditions.

Here are a couple of examples that highlight how these values can be interpreted in the field:

If a rise in fine-dispersed bubbles occurs, then this can be indicative of persistent gas transport through the system. This affects the oil’s compressibility and can even lead to a stability issue.
If there is a rise in the number of larger bubbles, this can indicate that there is localized entrainment, return-line impact, free-surface interaction, and stronger ingestion events. If these are not addressed in time, they can damage your components.
If one detects an increase in oil-air contact surface, this can indicate that gas distribution has become more degradation-relevant in the system. This may be despite no dramatic change in the total air content.
If transient bubble events are present, this can directly point to issues related to specific operating states rather than a general system condition that needs to be addressed.
If smaller bubbles occur, this leads to much worse thermal conductivity. As such, higher operating temperatures would need to be cooled down directly with a high amount of energy, or this can lead to a much higher thermal oxidation rate. In each case, the system efficiency is reduced.

These observations set the stage for more in-depth analysis and contextual interpretation to determine whether the pattern is fluid-driven, hardware-driven, or operating-point-driven. A workflow can be easily implemented to reduce risks to your operation, as highlighted in Figure 3 below.

Figure 3: Suggested workflow for monitoring air in your oil

A robust methodology for the characterization and optimization of your system should follow a structured measurement and interpretation workflow:

Definition of the System Baseline
The first step is to establish a representative baseline condition by continuously measuring the system’s actual operating state. These parameters should include temperature, rotational speed, torque, flow velocity, pressure conditions, and load states. The baseline must capture the dependency of the oil–air behavior on these operating variables to provide a reliable reference for subsequent evaluations and further steps.
Detection of Deviations and Dynamic Transitions
Deviations from the baseline are identified using real-time monitoring metrics and transient analysis. Changes in aeration behavior, bubble content, or flow characteristics are quantified relative to the reference baseline state established in Step 1. In parallel, a prioritization strategy should be defined to identify the most critical deviations and focus optimization efforts on the parameters with the highest system impact.
Contextual Interpretation of Deviations
Detected deviations must be interpreted within the system’s physical context. The origin of the observed behavior should be determined by correlating the measured size distribution and temporal system response with potential mechanisms such as splashing, churning, vortex formation, temperature variations, fluid aging, or changes in the operating point. This contextual analysis enables the differentiation between transient operational effects and systematic design-related issues.
Implementation of Targeted Corrective Measures
Based on the contextual interpretation, focused and goal-oriented design modifications can be implemented. Possible optimization measures include adjustments to return-flow geometries, improvements in suction conditions, reductions in churning effects, optimization of pressure levels, speed or load adaptations, fluid conditioning, changes to additive formulations, or enhanced filtration strategies. The corrective actions should directly address the identified root causes of the aeration behavior.
Validation Through Continuous Measurement and Improvement
The effectiveness of the implemented measures must be validated through continuous monitoring and iterative evaluation. Repeated measurements under comparable operating conditions ensure that improvements are sustainable and quantifiable. This closed-loop approach enables continuous system refinement and supports long-term optimization of the behavior of oil–air mixtures.

By moving beyond the standard quantitative measure of air in oil, we can address critical issues occurring in our equipment. By measuring and interpreting metrics correctly, you can optimize your system’s overall performance, make it goal-oriented, and keep it focused. This supersedes the often-used trial-and-error approach, which can ultimately damage your equipment.

For those interested in taking a more serious approach to understanding the health of their oil and preventing issues before they occur, the SBS can help improve the reliability of their system.

What you see is what you get!

Find out more in the full article, "Air in Oil: The Reliability Variable Many Programs still treat too late" featured in Reliable by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd, David Placzek, Dr. Lukas Hafner

Oil Properties / Reliability

How Is Air in Oil Measured?

When we think about measuring air in oil, the top-of-mind lab tests that are well known are the foam test (ASTM D892) and the Air Release test (ASTM D3427 & DIN ISO 9120). While these two tests can provide information on the tendency of foam to dissipate or for air to be released from the oil, they don’t give the entire story of what’s happening in the oil as it relates to air.

More specifically, they do not take into account the volume of air that can be trapped in your system during operation, nor how long it will take to dissipate when everything stands still. These parameters are critical for determining the impact of entrapped air in your oil.

People can also measure the volume of air in the oil, but 5% can mean different things depending on the air’s state, as shown in Figure 2 below.

Figure 2: Scenarios where the air (gas) volume of 5% can mean different things

As we can see in Figure 2, an air (gas) volume fraction of 5% may appear the same, but it can affect your system differently.

In Scenario A, the bubble sizes are larger, so these will rise to the surface more quickly and dissipate. As such, there are fewer disturbances and pressure fluctuations.

In this case, these might indicate localized entrainment, suggesting churning or impact from your return line. Another source could be coalescence, driven by oil properties, splash effects, and other factors. The risk of air bubbles becoming trapped in dead zones increases.

However, in Scenario B, the average bubble size is smaller, which means there are many more air bubbles in the oil! This means that there is a higher surface contact area and an increased potential for foaming. This can increase the rate of oxidation and, by extension, the risk of the oil forming varnish.

This also significantly affects the oil’s compressibility. With the advent of these smaller bubbles, there is usually system-wide aeration, such as vortexing or suction issues. The risk of inefficient cooling and overheating your oil in heaters has increased significantly.

With only a 5% air volume result, we would be missing critical information, such as what could be causing the issue or whether it is an immediate threat to our operations. This is where the SBS (Smart Bubble System) changes the entire game.

Find out more in the full article, "Air in Oil: The Reliability Variable Many Programs still treat too late" featured in Reliable by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd, David Placzek, Dr. Lukas Hafner

Oil Properties / Reliability

The Chemistry Behind Air in Oil

The oil’s chemistry also plays a significant role in determining its air content. All finished lubricants consist of base oil and additives. The characteristics of your base oil can determine important factors such as your viscosity, interfacial behavior, density, and gas solubility. The surface tension of your oil can also be affected by the size of the bubbles and how long they stay in that formation of the bubble.

Depending on the oil application, the appropriate ratios and types of additives vary. As such, there may be more emphasis on certain characteristics such as oxidation stability, viscosity behavior, or foam control. These additives all affect how long air can remain in the oil and the oil’s state, which can affect our machinery.

As shown in the video below, we can compare the air content percentage of an oil at varying temperatures and observe significant differences.

As shown in the first video, for a wind turbine gearbox using Optigear Syn CT320, the oil contains less air as the temperature increases, decreasing from 2% at 80°C to 0.7% at 110°C. At 110°C, we see a further decrease in air content to 0.65%. As the temperature starts decreasing again toward 80°C, we observe a volume with 2.2% air content in the oil. This is simply due to a temperature change in the oil, not to any additional air ingress.

As such, for the Optigear Syn CT320 oil in this wind turbine gearbox application, we can conclude that if the oil operates at temperatures around 80°C, we can expect up to 2% air volume in the oil. We observe that for lower temperatures, the air content may increase due to the impact of viscosity on air-release capability.

But if the temperatures increase (to a temperature that is tolerated within the system), then the volume of air will decrease, which is a good thing. However, as temperature increases, your chances of thermal and non-thermal oxidation also increase.

In the video above, we see a completely different behavior with the Fuchs Titan EG ATF D VI oil in an automotive gearbox, which starts off at 45 °C. There is a low air volume in the oil at 0.1%. However, when the temperature reaches 73°C, the volume of air increases by 0.7%.

The air bubbles are much larger, increasing the contact surface and their count within the oil. As the temperature decreases to 49°C, the volume decreases by 0.4%, and the number of bubbles decreases. With the continued drop in temperature to 44°C, the air volume decreases to 0.2% and then tapers off to 0.1%, with smaller, fewer bubbles.

In a wind turbine gearbox application using industrial gearbox oil, we observe that the air content decreases as temperature increases. Conversely, in an automotive gearbox using transmission gear oil, the air content increases with rising temperatures. This is very specific to the oils tested in these examples, as different oils will have varying ratios and types of additives and base oils, which can be affected in diverse ways.

The chemistry of the oil is, therefore, another critical part of understanding the air in your oil. If this is properly understood and measured, it can be very useful for monitoring your oil’s health in the field.

Find out more in the full article, "Air in Oil: The Reliability Variable Many Programs still treat too late" featured in Reliable by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd, David Placzek, Dr. Lukas Hafner

Oil Properties / Reliability

How Does Air Get Into Oil?

Air is inert, so it shouldn’t affect your oil, right?! This is a concept that many people get wrong or don’t fully understand. Air in your oil can literally cost your facility millions of dollars in damage if it is not treated or removed from your system early.

It can affect the compressibility of your oil, its thermal behavior, and the oxidation stability of hydraulic and drivetrain systems, leading to degradation or efficiency loss. With reduced efficiency, overall production will decline, which can negatively impact the profitability of your operations. Before we dive into the ways it can affect your system, we need to understand the basics.

The Four States of Air in Oil

Air can exist in four states within your oil and machine. As shown in Figure 1, these include;

Dissolved air
Entrained air
Foam
Headspace interaction

Figure 1: Different states in which air exists in your system

Each of these states can affect your system differently, as shown in the table below, and will have corresponding sources of ingression.

Reliability Meaning for Various States of Air

State	Reliability Meaning	Typical Sources
Dissolved Air – this usually represents 8-12% of dissolved air at atmospheric pressure	Affects solution chemistry. Can come out of solution when pressure, temperature or shear conditions change. Often a hidden source for future entrained air.	Equilibrium with headspace air usually in the sump, make up oil (when oil is added to the sump), storage, temperature or pressure changes.
Entrained Air	Reduces effective bulk modulus (compressibility). Has a big impact on control stability, efficiency, and thermal behaviour. Drives cavitation and microdieseling risk. Even with a 0.5% volume of air, this can triple the risk of varnish. Controllability of valves gets affected. Maximal suction height of pumps is reduced dramatically.	Suction leakage, vortexing, return-line splash, churning, gear mesh aeration, system design. However, strong pressure reductions lead to de-aeration of the dissolved air.
Foam	Indicates strong surface activity or contamination. Can reduce effective oil volume, impair heat transfer and promote aeration carry-over.	Surface active additives, detergents, contaminants, high turbulence, agitation.
Headspace Interaction	Drives how much air enters or leaves the oil over time. Influenced by temperature, pressure, ventilation and oil level.	Breathers, vents, temperature cycles, pressure changes, low oil level.

For each of the states above, air affects the reliability of your equipment. It is critical to identify the state of air in your oil so it can be removed before it begins to affect your system. Typically, maintenance teams pay attention to air in oil only when it is visible (foaming) or when it demands their attention through noisy interactions. By this time, teams have lost the opportunity to remove the air while it is in its more benign state.

How Does Air Get Into Oil?

When we think about air getting into our oil, we generally think of openings or mechanical areas that allow it to enter. However, air can enter our system in several ways. It is also worth noting that air already exists in the oil at equilibrium, where it will leave the oil according to Henry´s law.

Air can become entrained (or trapped) in the oil through various mechanisms such as return-line splash, vortex formation, suction-side leakage, tank dynamics, free-surface interaction, or churning in gearboxes and drivetrains. When entrained, it can cause damage to your equipment if not detected in time.

Changes in operating regimes can also influence whether air stays in the oil or gets forced into it. This is usually seen with changes in pressure, temperature, or shear conditions. Within your system, your oil can experience a load transition, a change in oil level, or return flow, all of which can influence the volume of air that remains in or enters your oil.

Even after identifying the source of air ingress, it is imperative that it be removed from your system. While air in oil does not usually get the attention it deserves, it will demand that attention if it goes unresolved or remains in your system.

Find out more in the full article, "Air in Oil: The Reliability Variable Many Programs still treat too late" featured in Reliable by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd, David Placzek, Dr. Lukas Hafner

Oil Properties

What Tools Can Be Used to Monitor Additive Depletion?

There are some basic analytical tools that can be used to measure the quantity of additives in oils. The spectroscopy methods are the FTIR (Fourier Transform Infrared) and ICP (Inductively Coupled Plasma). Another method is the RULER® test exclusively designed for antioxidants.

With FTIR and ICP methods, users obtain quantitative values for the elements present in the tested oil sample. These are usually reported in ppm and trended over time. Figure 2 shows an extract from a Turbine Sample report from Eurofins lab, where the levels of additives (and contaminants) are shown. When trending this, analysts should pay attention to the rate at which these additives decrease and whether an increase or decrease is noticed.

What Tools Can Be Used to Monitor Additive Depletion

Figure 2: Sample of Eurofins Turbine Oil Analysis Report showing the levels of additives

Another tool that can be used is the RULER® (Remaining Useful Life Evaluation Routine) test, which specifically quantifies the levels of antioxidants remaining in the oil. It trends the values, compares them against the baseline for that oil, and then determines the change as a percentage.

If the RULER value falls below 25%, the antioxidant levels have reached a critical level, and one may consider replacing the oil.

Figure 3 shows a RULER graph, which identifies the presence of different types of antioxidants (Amines) and antiwear additives (ZDDP), as well as oxidation products (Fluitec, 2022).

This is a comprehensive readout of the quantities of these additive types at the time of sampling. It is easy to get a quick snapshot of its trend over time and determine whether it is declining rapidly or reaching critical levels.

Figure 3: RULER Graph showing the presence of antioxidants

The key to using these analytical tools is to provide insight into what is happening inside the equipment, allowing us to determine whether any preventive action is needed.

By monitoring the quantities of these additives over time, we can easily establish whether oxidation is occurring, which can lead to varnish and overheating of the asset. We can also determine whether significant wear is occurring as the antiwear additives are depleted (confirmed by the presence of wear metals in the oil analysis). When monitoring your asset’s health, trending specific additive levels can also be very useful.

References

Eurofins. (2025, September 06). Annual Turbine Analysis. Retrieved from Eurofins Testoil: https://testoil.com/services/turbine-oil-analysis/annual-turbine-analysis/

Fluitec. (2022, September 29). Why is LSV Used for RULER Analysis? Retrieved from Fluitec: https://www.fluitec.com/2022/09/29/why-is-lsv-used-for-ruler-analysis/

Find out more in the full article, "Lubricant Additive Depletion as an Early Asset Health Signal" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd.

Oil Properties

How Can Additives Deplete?

Additives can be depleted through different mechanisms. Some of these include:

Regular consumption through normal functioning of the lubricant
Antioxidant depletion during oxidation
Antiwear depletion due to high wear on the inside of the equipment
Additive depletion via a contaminant to produce a bleaching effect

As mentioned earlier, additives are sacrificial in nature. It is very normal to see additives deplete over time; if they are not depleting and increasing, this may be a cause for concern. This can mean that someone is topping up the oil frequently or perhaps topping up with an incorrect lubricant.

Since there are numerous oils on the market, the best way to monitor the depletion of your additives is to compare them against a new sample of that oil and use that as your baseline. Your lab will help you confirm when the additive limits are approaching the danger zones.

During oxidation, a free radical is formed under conditions such as heat, wear, metal catalysts, oxygen, or water. These free radicals are unstable, and antioxidants usually neutralize them.

In the process, antioxidant levels decrease. However, if the conditions still permit oxidation, more free radicals will be formed. This means that more antioxidants will be depleted as they neutralize the free radicals until they diminish and can no longer protect the base oil. This is when the free radicals begin to attack the base oil, and varnish can form.

Once the antioxidants are gone, the oil stops defending – and starts degrading.

If there are causes of high wear, such as the incorrect viscosity of the lubricant (too thin) or the machine finishing of the inner parts of a component not being done to the required standard, this can affect the levels of antiwear in the oil. Antiwear additives protect the metal surfaces inside the equipment. However, these are only activated when moderate stress exists within the equipment.

Typically, in these situations, the antiwear additive adheres to the metal surface and helps protect it by forming a layer. Once this layer is formed, the antiwear additive has officially left the oil, and this will be reflected in a decrease in its value in the oil analysis report.

The layer will not remain forever, and due to wear on the equipment, it can be worn off and replaced by a new layer, leading to further depletion of the antiwear additives until there are no more to form another layer or protect the metal surface.

Contamination can also cause some additives to become depleted. Contaminants can react with additives, causing them to form deposits that leave the oil. Therefore, their presence will not be detected by oil analysis.

Some common contaminants are water, fuel, coolant, and acids. These contaminants can also promote the formation of catalysts for degradation mechanisms such as oxidation. Dirt and solid particles can also promote additive depletion, especially when they act as catalysts.

Find out more in the full article, "Lubricant Additive Depletion as an Early Asset Health Signal" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd.

Oil Properties

Why Do Additives Matter?

Oils are composed of base oils and additives. Typically, additives are sacrificial; they deplete first before the base oil is affected. As such, by trending their quantities over time, we can gain insight into a few of the conditions to which the oil is subjected.

By interpreting these conditions and patterns, we can correlate them with the health of the asset and plan accordingly for possible repairs or maintenance. In this article, we will do a deeper dive into ways these can be explored to add value to your asset management program.

Additives come in various ratios and chemical compositions, but when we talk about additives in oils, they really have three main functions. They can either;

Enhance the properties of the base oil, which already exist
Suppress the undesirable base oil properties or
Impart new properties to the base oil

Figure 1: Functions of additives and examples

On their own, they cannot affect anything, but when coupled with a base oil, they can impact an asset. Base oils also have specific properties, which, when combined with additives, allow assets to perform at their best.

The real performance comes from how the additives and base oil work together.

As shown in Figure 1, some additives that enhance properties include antioxidants, corrosion inhibitors, anti-foam agents, and demulsifying agents. Those responsible for suppressing undesirable properties can include pour-point depressants and viscosity improvers.

Finally, those responsible for imparting new properties include extreme-pressure additives, detergents, metal deactivators, and tackiness agents.

Here are some quick descriptions for a few of these additives, which will help you to gain an appreciation of their functions:

Antioxidants: these protect the oil from oxidation. They are very common in Turbine oils but can be found in many other oils. They are the first line of defense when oxidation begins and react with free radicals to neutralize them before they attack the base oil.

Corrosion inhibitors: adsorb onto the metal surfaces to help protect them. Comprised of sodium sulphonates, alkylbenzene sulphonates, or alkylphosphoric acid partial esters.

Anti-foam agents: reduce surface tension to break up foam formation. Typically, these are silicon-based, although silicone-free defoamers also exist.

Demulsifying agents: enable water and oil to separate. These were formerly composed of barium and calcium, but modern formulations use special polyethylene glycols.

Pour point depressant: alters oil crystallization, allowing the oil to form fewer crystals at lower temperatures.

Viscosity improvers: specifically designed to ensure that the viscosity of the lubricant can be more tolerant of changes in temperature and shear.

Extreme pressure additives: used under high stress to prevent the welding of moving parts. Usually comprised of a phosphorus compound.

Antiwear additives: designed to reduce wear under moderate stress. The most famous sulphur-phosphorus compound is ZDDP (Zinc Dialkyl dithiophosphate).

Detergents: keep oil soluble combustion products in suspension (especially for engine oils) and ensure they do not agglomerate. These usually contain metal additives such as Calcium and Magnesium.

Understanding the function and composition of these additives can help us to determine how they are performing in the oil. Since many of these are sacrificial, their values will decrease over time. As such, it is important to trend these values to determine whether they are remaining constant, increasing, decreasing, or decreasing at an accelerated rate.

Find out more in the full article, "Lubricant Additive Depletion as an Early Asset Health Signal" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd.

Lubricant Degradation / Oil Properties / Reliability / Storage & Handling of Lubricants / Used Oil Analysis

Role of Condition Monitoring, Human & Organizational Factors in Oil Failures

Choosing the right oil for the system is just one part of the puzzle. How do we know the oil is performing when it’s in the system? This is where condition monitoring can work hand in hand to help ensure that the oil does not fail the asset.

If a proper oil analysis program does not exist, operators will not know whether the oil is properly lubricating the asset. They will also not be aware of whether the oil is breaking down too quickly and failing to protect the asset. Oil analysis can also alert operators to signs of wear in the asset, so they can fix them before they turn into functional failures.

An oil analysis program that lives in a drawer protects assets about as well as no program at all.

Role of Condition Monitoring, Human & Organizational Factors in Oil Failures

There is also the possibility that an oil analysis program exists but is not top of mind, or that its results are put in a drawer. This can also cause the asset to fail even though the correct oil is being used. Apart from the aforementioned factors, if operators are not warned of the impending failure of the oil, this can result in production losses, increased downtime, and, in some extreme cases, the complete loss of the asset if it has failed beyond repair.

Incorrect sampling is another area in which the actual condition of the asset is not reported. Even with the correct oil used, if a sample is collected from a dead leg or an area that is not truly representative of the conditions inside the component, its actual condition will not be known. With incorrect data about the component, the asset can be misdiagnosed or treated for symptoms that do not exist, which can lead to its detriment.

Human and Organizational Factors

Not all failures occur at the equipment level; human and organizational factors can also cause the asset to fail even when the correct oil is used. If humans aren’t properly trained in oil sampling techniques or storage and handling practices, these can affect the asset’s functionality. We often forget that, at the heart of it all, lies the human factor, which is partially governed by the organization’s systems.

Training needs are an organizational factor that is often overlooked when considering how an asset can fail. However, if operators have not been trained in condition monitoring techniques, they will not be able to read oil analysis reports or take appropriate actions to protect the asset. Training can help bridge some competency gaps that directly impact asset performance.

It doesn’t matter what oil is in the system if no one is trained to monitor it – or motivated to care.

Culture is another factor swept under the rug. If the culture doesn’t exist to look after the assets, it doesn’t matter what type of oil is placed in the system; the asset will fail eventually. The performance of the asset does not only rely on using the correct oil. By implementing a culture of Asset ownership, where operators look after the asset and are accountable for its performance, assets are optimized to provide the functionality they should. This is one way to ensure the right oil is used to enable the assets’ performance.

Another area of concern is the documentation of maintenance procedures. If maintenance procedures are not adequately documented, someone new to the operation may not be aware of the correct practice. This, coupled with a lack of training, can spell disaster for the equipment. In these cases, even though the right oil was selected, the wrong practice or lack thereof can fail the asset.

Turning the “Right oil” into the “Right Outcome.”

As explained in this article, improper practices can jeopardize the asset’s health, even when the right oil is used. However, if all the right things align, we can have an asset that lasts for its expected lifetime or beyond.

This starts with selecting the right oil based on the application, environmental conditions, and OEM recommendations. If we follow this up with good storage and handling practices, proper condition-monitoring programs, documentation, and training, we can look toward a longer-lasting asset. The right oil enables reliability – but only disciplined practices deliver it.

Find out more in the full article, "When 'Right oil, Wrong practice' still fails assets" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd.

Lubricant Degradation / Oil Properties / Reliability / Storage & Handling of Lubricants / Used Oil Analysis

Common Modes of Failure for Lubricants

Regardless of the oil selected, common modes of failure can occur with every lubricant. These include: contamination, improper storage and handling practices, and environmental factors as shown in Figure 4.

Contamination can be defined as any foreign particle entering the system. This includes any gases, liquids, or solids. Especially when the lubricant system runs alongside the process side, process gases and liquids can leak into the oil. These contaminants can influence the oil’s degradation, leading to deposits or chemical reactions that break it down. Common process contaminants include ammonia or treated water.

The biggest threat to the right oil is often what gets added to it – whether it’s process contamination or the wrong oil during a top-up.

Another liquid that can contaminate oil is another oil. During top-ups, operators can add the wrong oil to the system, causing contamination and, depending on the oil, a possible shutdown. Adding motor oil to hydraulic oil can be catastrophic, as the additive packages work differently and the motor oil additives may counteract the hydraulic additives, removing them from the oil, leaving the asset open to wear and failure. Despite selecting the correct lubricant for your system, adding the wrong oil (mistakenly) will shorten its lifecycle and cause the asset to fail.

Bad storage and handling practices can also erode your oil, regardless of the oil you choose. Turbine and hydraulic oils are used in precise equipment. As such, they need to be clean and free of dirt or other contaminants. However, if oils are not stored correctly, contaminants can enter and contaminate the oil.

Simple techniques, such as transferring oil from larger storage containers (pails, drums, or totes) into smaller, more manageable containers (2-3 liters or less), can introduce contaminants into the oil if not done correctly. If oils are to be transferred to another storage container, the storage container must be clean. The transfer process should use clean hoses (not previously used for another lubricant) and be completed in a dust-free environment.

If you wouldn’t use a dirty needle for a blood transfusion, why would you use a dirty hose for an oil transfer?

The transfer of oils from one container to the next can be thought of as a blood transfusion. Would you use dirty needles or vials to transport the blood to be placed into another human? Similarly, oil can be likened to the equipment’s lifeblood and should be treated accordingly. Just as we observe sterile practices for blood transfusions, we should also observe similar types of practices for oil transfers.

Environmental and operational factors can also influence lubricant degradation. As stated earlier, all lubricants can degrade over time under harsh conditions. The lubricant formulation largely influences this, as does whether it was blended to withstand those conditions.

Oxidation can easily occur when temperatures increase, free radicals are present, or when wear metals are present. Thermal degradation occurs when the temperatures exceed 200°C. On the other hand, microdieseling occurs in the presence of entrained air, despite the lubricant used in the system, as shown in Figure 5.

Figure 5: Lubricant Degradation Processes

Any of these degradation mechanisms can occur regardless of the type of oil chosen. Hence, it is essential to remember that operational conditions and environmental factors can heavily influence oil degradation, even when the oil is appropriate for the system.

Find out more in the full article, "When 'Right oil, Wrong practice' still fails assets" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd.

Oil Properties / Reliability

Spec Sheet vs Strategy for choosing the right oil

Sometimes we can spend hours poring over technical data sheets, comparing oil performances, and finally selecting the “right” oil which aligns with the needs of our equipment. Then, within 2 months, the oil degrades, our machines shut down, and we have a bunch of maintenance repairs lined up. What went wrong? We clearly had the “right” oil in the equipment; everything should have worked beautifully. This is where the awareness of lubrication and its practices becomes critical.

Having the correct oil is only one part of the puzzle. Being able to deliver that oil in its purest, cleanest form to the machine is often one of the other pieces that go missing. Another piece is selecting the right oil, not just based on the sales guy’s advice, but on the actual operating conditions of your machine. In this article, we dive a bit deeper into ways you can align the right oil with the proper practices, or avoid the wrong ones, to help extend the life of your asset.

Spec Sheet vs Strategy

For this example, we will consider a turbine oil selection. If a customer wants to change the oil in their turbine, then they may consider the following:

What are the OEM specifications that need to be met?
Is this oil available from the local supplier?
How does it compare to other oils on the market?
Does the cost justify the value? (or will the purchasing department want something cheaper?

For most of these questions, engineers or the person tasked with selecting the oil can readily find the answers in the oil’s technical data sheet and by talking to their sales representative. But if we dive a bit deeper, are we selecting the right oil for the operating and environmental conditions? Let’s examine the selection of a turbine oil for the Siemens SGT 200 Gas turbine that meets the Siemens TLV 9013 04 specification.

As seen in this document from Shell Lubricants, a few of their products meet that specification, namely Shell Turbo T, Turbo S2GX, Turbo S4X & Turbo S4GX.

Figure 1: Shell Turbo Family for the Siemens TLV 9013 04 Specification

On the other hand, Mobil provides some solutions as well, namely, Mobil DTE 732, 746, or DTE 832, 846

Figure 2: Mobil DTE 700 & 800 Series meeting the Siemens TLV 9013 04 Specification

Chevron also provides an option of Chevron GST as follows:

Figure 3: Chevron GST oil meeting the Siemens TLV 9013 04 specification

With so many options, how can one choose the “right” oil? They all meet the required Siemens specification, TLV 9013 04. This is where the data sheets, OEM manual, and knowledge of the equipment’s operating conditions play a crucial role.

As per the manual, there are preset conditions for temperatures and pressures, but if your actual system runs hotter (or production is being pushed a bit more), it is functioning outside the operating envelope.

The spec sheet tells you what the oil can do. Your operating conditions tell you what it must do.

Additionally, if your surroundings are harsh (close to the sea or in a corrosive environment, or in a non-ventilated area where heat can build up), these can place additional stress on the equipment. For these harsher conditions, a synthetic oil might be more appropriate than a mineral oil, albeit more expensive in terms of the initial investment.

The manual also specifies which tests/characteristics should be used to monitor the condition of the oil, namely: viscosity, particle count, water content, demulsibility, air release, foaming characteristics, RULER®, and MPC. Based on the performance of your current oil in the system, you can determine whether these values fluctuate toward the higher warning zones. This can also influence your decision about which oil to choose.

It’s not just about the right oil or one that aligns with OEM requirements. The selection should also be based on the environmental conditions of the oil and the equipment, and on whether the oil is suited to perform in these conditions. A mineral oil will not withstand the temperatures that a synthetic oil can for extended periods without degrading. Similarly, given the “right” conditions, synthetic oils can also degrade. By cross-examining your spec sheet, OEM manual, and actual conditions, you can determine the best-suited oil for your operations.

Find out more in the full article, "When 'Right oil, Wrong practice' still fails assets" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd.

Tagged: lubrication

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References

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