Mechanical Technology November 2015

⎪ Proactive maintenance, lubrication and contamination management ⎪

In the final Mario on maintenance column for 2015, Mario Kuisis summarises the key messages for the year, lists some recent technology innovations and warns against straying from the fundamental rule of physical asset management. Proactive maintenance: beyond the starting line

Mario on maintenance:

T o wrap up proactive mainte- nance in 2015, let’s review what we’ve discussed this year and delve a little deeper into some of the aspects that we touched on, but left for further consideration. Firstly, let’s remember that each organ- isation wishing to optimise asset care must thoughtfully choose between pas- sive, reactive, preventative, predictive and proactive maintenance strategies. We need to do this per asset and/or major component. Each strategy has a rightful place in our maintenance mix and particular set of circumstances. In deciding, we must consider the relative importance of reliability against finan- cial, reputational, safety and environ- mental matters. We also note that these are not invariable and, therefore, the process needs to be repeated at least every few years as the asset ages and

business circumstances change. We discussed some of the pitfalls of the late introduction of predictive main- tenance into an organisation and con- cluded that it is a process that must be handled carefully and that it takes time as a minimum level of maturity must be reached. Only then can the full benefits of proactive maintenance be realised – by revisiting and adapting preventative maintenance plans to reduce costs and enhance reliability. After all, why put cost into maintaining an asset that has no need of it and increase the risk of an infant mortality incident? It is also useful to be reminded of the insight into both asset health and performance afforded by predictive maintenance techniques. This brings the potential for useful contributions directly to the business bottom line by improving plant performance and efficiency, in ad-

dition to reliability. Which, incidentally, also ticks the right boxes in a number of environmental and safety aspects. We mentioned, but did not discuss, available technology options: scope and applications; relative ease of use and cost; method of application; etc. This is an important topic and worthy of delv- ing deeper, but very wide ranging and constantly changing as technological advances permit improved performance at lower cost. This is good news for the new entrant, but also means that if you want a good and sustained outcome you must do your homework properly before investing, then stay abreast of developments. The four pillars of condition monitor- ing remain vibration and oil analysis, thermography and ultrasound detection. Do not proceed without first examining the present state of the art and the merits of each of these in detail. Incorporate them as necessary and remember that they are complementary technologies with limited overlap. Also bear in mind that very effective techniques are now available for monitoring the condition of many non-rotating assets. If you have some unusual problems, or want to explore beyond the conventional, then listed below are some relatively recent innovations that are being put to good use for predictive maintenance by way of continuous on-line methods. • Optical fibre as the sensor for moni- toring distributed vibration; dis- tributed acoustics; and distributed temperature. • Surface acoustic wave passive wire- less sensors for monitoring tempera- ture; torque; pressure; and strain. • Gas chromatography for monitoring gases, including dissolved gases in oil. • Conductivity and permittivity for monitoring the quality of lubricating and transformer oils. • Multi-spectrum structure-borne acoustics for monitoring boilers; heat exchangers; product flow (coal, ore, etc.); and rotating assets.

The four pillars of condition monitoring remain vibration and oil analysis, thermography and ultrasound detection.

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Mechanical Technology — November 2015