Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1080534
ML www . machinerylubrication.com | January - February 2019 | 5 paler, but the color may graduate to darker tones toward the halo periphery. e color transitions suggest some particle mobility and that most of the particles are quite small (less than 3 microns). is can occur when the larger particles are selectively stripped from the oil by sump stratification (sediment) or filtration (in circulating systems). When oil is changed infrequently, there can be a considerable buildup of small particles, often called ghost riders. For more on this subject, please refer to my article in the July-August 2018 issue of Machinery Lubrication. e blotters shown on pages 2 and 4 are mostly from industrial gear and bearing oils exhibiting abnormal levels of wear metals. All blotter images are roughly the same size as when they were created, i.e., no magnification. Interpretation of these blotters is always subjective and influenced heavily by the experience of the analyst, knowledge of the machine and operating conditions/exposures, and the ability to trend from a succession of previous blotters (same machine) or from blotters from similar machines. Note the elemental data on the oils used in the blotters shown on pages 2 and 4. Be mindful that elemental analysis is largely unable to quantify the presence of particles larger than 3 microns. Conversely, these larger particles are quite visible on the blotter, especially aided by microscopy. Other tests and inspections can also aid considerably in the interpretation, including patch testing, magnetic plugs, bottom sediment and water (BS&W), used filter inspections, ferrous density testing, secondary oil sample inspections, vibration, acoustic emissions and thermal imaging. Like most condition monitoring methods, blotter spot testing adds information or data to help answer questions about machine health and lubricant condition. It can provide an effective screen for numerous conditions or potential alerts. In many cases, it must be combined with other methods to enable a more complete characterization of condition and health. Despite its low-tech simplicity, it should never be ignored or underestimated in terms of importance to the field of condition monitoring and machine reliability. ML About the Author Jim Fitch has a wealth of "in the trenches" experience in lubrication, oil analysis, tribology and machinery failure investigations. Over the past two decades, he has presented hundreds of courses on these subjects. Jim has also published more than 200 technical articles, papers and publications. He ser ves as a U.S. delegate to the ISO tribolog y and oil analysis working group. Since 2002, he has been the director and a board member of the International Council for Machinery Lubrication. He is the CEO and a co-founder of Noria Corporation. Contact Jim at jfitch@noria.com. PENETRATES. LUBRICATES. PROTECTS. Unlike ordinary rust solvents, Penetro's exclusive oil-based formulation not only breaks through rust, it coats metal surfaces with a lubricating film that won't wash off. • Triple protection against rust. • Triples the life of hoist chains and sprockets. • Prevents thread stripping. schaefferoil.com 314.865.4100