How clean is your oil?
March 1st 2008

Effective lubrication management should be a vital part of any structured maintenance program particularly within the food and beverage sector, but in many cases companies fail to take advantage of the benefits afforded by this discipline says AV Technology director John Chappell

Lubricants are the life-blood of any food or beverage 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.

Structured testing and reporting is an important part of the process, especially where they may be hundreds or thousands of lubrication 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. The bearing failure is the symptom not the cause. 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.

The correct choice of lubricant for a particular piece of equipment and application is the first and most fundamental part of any lubrication management program. 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 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 this investment 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. 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 photos below show two oil cleanliness checks in accordance with ISO 4406. The standard provides a 3-part code to represent the number of particles per millilitre (ml) of fluid greater than 2µm, 5µm, and 15µm respectively. Note there is approximately a thirty fold increase in particle numbers between 14 and 19 in the code.

It can be seen that the one system (14/13/10) is very clean and well managed, while the other (19/18/16) is from a typical system in operation where there is a relatively high level of contaminants. This may be deemed acceptable by some parties, but if this second sample is from a lubrication system based on a food grade lubricant and the question is asked: "Is the system clean to a food safety standard?" the reactions will almost certainly be very different.

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. 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 program has a number of very cost effective benefits and as John concludes: "AVT provides customers with maintenance optimisation and equipment reliability improvement services. Thereby 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."

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