What happens when the life of the lubricating oil is shorter than expected?

What happens when the oil life is shorter than expected?


In critical machinery, an unscheduled downtime caused by failure or malfunction can stop the entire production line. This is why knowing what shortens the service life of lubricating oil in critical machinery is very important.


Causes of shorter lubricant service life




Lubricating oils in machines operating at elevated temperatures for a long time will have higher degradation rates. Therefore, keeping the lubricants at the lowest possible temperature helps extend their service life while reducing degradation rates.




Oxygen is the main oxidising agent in oil base oxidation, the chemical reaction that occurs when base oil and oxygen come into contact. Oxidation will lead to an increase in oil viscosity and deposits of varnish and sludge. As a further effect of the presence of oxygen, additives get depleted, and in extreme cases, this may involve corrosion.




Water contamination, particles from airborne dust and other external contaminants can be catalysts that speed up the oil degradation process and facilitate chemical reactions. Other contaminants are the degraded oil itself, metal particles (copper or iron), acids and water in the system.



Effects of shorter lubricant service life


To detect the causes of oil degradation, applications need to be analysed separately. However, in general, best practices in lubrication management, as part of a proactive process, can help minimise lubricating oil degradation. Basically, best practices include keeping the lubricant clean (which can be achieved by adding filters or using filters with smaller pore sizes), increasing the beta ratio (filter efficiency) if necessary, replacing the method used to eliminate air, and detecting water contamination.

The wind energy industry is a case in point. Turbine components wear gradually over time because they must operate at temperatures lower than 65 °C. However, air ingress affects lubricant degradation, speeding up the process. A gearbox or a forming press have characteristics of their own. A reliable way of ‘extending’ the service life of lubricating oils consists in operating the equipment at the lowest possible temperature, so that the oils keep its desired properties. This, however, cannot be done in every application.


Evaluation test: Is your plant at risk of a shutdown? 


Lubricating oil degradation poses risks for the lubricant itself as well as for the equipment. Rarely does it occur in isolation, as in most cases it comes as a result of a number of negative factors that have damaging effects on the lubricant.

Different types of industrial applications use different types of lubricants, some of which can be subject to contamination due to factors such as process constituents or inadvertent mixing of a different fluid. Mixtures of lubricants can be detected, and the impact of such contamination must be considered when maintenance decisions are made. When lubricant assessment shows abnormal values, the maintenance staff must decide whether to replace the lubricant or not. More often than not, lubricant replacement costs are high.

Furthermore, adequate monitoring helps detect fluid compatibility. Sometimes, the synthetic oils used in a given process are incompatible; some other times, remnants of the previous oil undergo chemical reactions. As a result, the filters become clogged, additives are lost, and other problems may arise that make it necessary to stop the machine.



Is it possible to maximise lubricating oil service live in critical machinery?


Lubricating oils have a service life marked by degradation. Their life can be extended by maintaining the oils clean, minimising water ingress and air contamination, and keeping a low temperature. These are essential measures that should be taken from day one.

Plus, lubricants should be kept away from all types of particles if possible. This can be more of a challenge in certain applications.

There are a variety of methods for determining the condition of lubricants, including monitoring sensors. Accurate lubricant diagnostics can be obtained with these types of sensors, including such information as acid number, oxidation changes determined by FTIR, antioxidant monitoring by RULER technology and oil viscosity.

Regarding particles, they are quantified and classified by size using the ISO 4406 codes. All this information is delivered as a series of percentages and indicators that help maximise the service life of lubricating oil in critical machinery.


Evaluation test: Is your plant at risk of a shutdown? 



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