How clean is your oil?

Lubricants are the life-blood of any industrial plant and in the same way that blood analysis can tell us vital information about our body and health, lubrication analysis can give an insight to the operational health of plant equipment. In parallel, in the comparable way that blood needs to be regularly cleansed, so lubricants can also benefit from regular cleaning.

There is no doubt that a well implemented Lubrication Management Programme will improve equipment reliability in the same way that a healthy lifestyle keeps us fit. Given the critical nature of lubricants and the frequency with which mechanical failure is related to the lubricating system, effective lubrication management is probably the most important single function within any planned asset maintenance programme, especially when combined with other effective maintenance practices such as alignment, condition monitoring and filtration. In a typical plant, lubricants include greases, gearbox oils, vacuum pump oils, compressor oils and hydraulic oils, each playing a critical role in keeping the plant operational.

Despite this, many companies often pay scant regard to the ‘life-blood’ of their plant, typically reacting to problems as and when they occur. Understanding the role of lubrication and how it impacts on equipment reliability is a key issue to implementing an effective maintenance and equipment reliability programme.   Structured testing and reporting is an important part of the process, especially where they may be hundreds or thousands of measurement points around the plant.

Inaccurate or ‘isolated’ reporting will almost certainly fail to bring the required 'measure-control-improve’ ethos to ensure increased plant uptime. If an item of rotating equipment fails for instance, the cause of the problem is often erroneously attributed to a bearing failure. Of course the bearing failure is the symptom not the cause and without looking into why it failed, and if the bearing is routinely replaced then almost certainly similar problems will continue to occur.  An effective lubrication, condition monitoring and contamination control ‘integrated maintenance solution’ applied to a well managed rotating equipment system will deliver significant improvement in equipment reliability. Such maintenance systems are focused on managing more effectively and designing out the failure modes, thereby delivering reduced operating costs which in turn lead to improved manufacturing performance.

The correct choice of lubricant for a particular piece of equipment and application is the first and most fundamental part of any lubrication programme. This has to take into account factors including materials and construction of moving parts, environmental operating conditions, including temperature, water resistance and cleaning routines, sources of contamination and legislative requirements (NSF H-1) supporting Food Safety Regulations, such as HACCP.

There is clear evidence that synthetic lubricants offer considerable advantages over their mineral equivalents, offering improved operating performance and increased longevity.  ‘Best in Class’ food grade lubricants are synthetic lubricants and for legislation compliance reasons companies do not find it difficult to justify the increased expenditure on these lubricants which may cost up to 10 times that of their mineral lubricant equivalents. However companies fail to capitalise on the investment in synthetic lubricants by not endorsing an effective maintenance system incorporating optimum control of techniques such as alignment, balancing and contamination control.

Independent studies by numerous authorities over the years have concluded that contamination is the most prolific reason for failure of equipment. Despite this, the justification in the investment for improved contamination control such as filtration and lubrication management is often difficult to appreciate within most organisations. However having invested in food grade lubricants (synthetics) at a significant cost for food legislative reasons, why not seek a return on that investment through the improved maintenance and equipment performance these products can deliver when included in an optimum managed system?

Furthermore an NSF H-1 food grade lubricant is made from component parts that are classified as safe where incidental food contact may take place. However the level of contaminants allowed to build up in an oil can negate this safety factor, highlighting the importance of oil cleanliness.

The improvement in equipment reliability that will be obtained from a clean oil system is well documented, but unfortunately this key factor is often overlooked. AV Technology’s Director John Chappell is passionate about system criticality of oils and lubrication methods, openly admitting he is somewhat frustrated by the lack of importance some companies attach to this vital subject. He is also keen to point out that the lubrication function cannot be effectively carried out by relatively low skilled oilers and greasers, walking around with an oily rag, oil can and grease gun. Equipment does need regular lubrication but as he explains: “Lubrication is a science (*Tribology) all of its own and the selection of the correct lubricant is as important as the lubrication process itself. Our extensive experience shows time and time again that a well implemented lubrication programme delivered by competent maintenance practitioners brings so many benefits and yet so few companies take full advantage of these. For instance, all too often companies have fixed oil and filter change out periods, which may, or may not be suitable or economic for any one particular scenario. Not only do they throw away oil which may still be serviceable if treated appropriately, but by not carrying out routine analysis, they may fail to identify possible sources of future problems.”

Outsourcing lubrication management as part of a wider condition monitoring programme has a number of very cost effective benefits and as John concludes: “It provides customers with maintenance optimisation and equipment reliability improvement services. In the case of AVT our engineers are maintenance surveillance engineers applying valuable maintenance methods such as vibration analysis, thermography, lubrication, and filtration management. All these core competencies are applied by skilled engineers who truly understand the importance of such techniques in maintaining and improving equipment reliability. However, more importantly, they are maintenance practitioners who have an in-depth understanding of the equipment they are maintaining and therefore have a deep appreciation of the impact the above key methods have on equipment performance.”

In summary, high performance lubricants will provide measurable benefits provided they are well managed and maintained, and applied by skilled maintenance practitioners.  Lubrication resource optimisation, which includes other key maintenance techniques such as vibration analysis and contamination control, is proven to enhance equipment performance. In parallel, good filtration management (contamination control) will enhance the life of equipment and oil significantly. The food industry more often that not will have already invested in the above technologies, therefore integrating the core methods and skills into an integrated maintenance approach will enhance HSE, food safety and maintenance standards.

Tribology is the science and technology of friction, lubrication, and wear, derived from the Greek tribo meaning ‘I rub’. Formally defined, it is the science and technology of interacting surfaces in relative motion and all practices related thereto. The study of Tribology is commonly applied in bearing design but extends into other almost any aspect of modern technology. Basically any product where one material slides or rubs over another is affected by complex tribological interactions, whether lubricated or unlubricated.

This article was originally published for Jan/Feb 2008 at http://www.maintenanceonline.co.uk/article.asp?id=1057&typ=all

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