Chemical Processing - June 2008 - (Page 28)

cant parameters including machinery wear particles, contamination, and lubricant or additive degradation. Truly meaningful lubricant analysis programs encompass testing a wide range of parameters using a variety of methods. Some of the more common test areas are: • Color and appearance. Regularly check these characteristics. For oils too dark for effective appraisal, reduce the volume of oil to a constant depth for proper observation. • Viscosity. Oils found to be outside specification always are considered abnormal. However, a change within a grade also can be a sign of trouble. Watch for changes of 10% from new oil. Lubricant anaLysis • Base number. Compare the alkalinity values (base Lubricants represent vital sources of information number) of the used diesel engine oil to new oil. As ready to be unlocked and evaluated as part of a CM a general rule, change oil when the alkalinity value program. Results enable operators to confirm use of the used oil is 50% of the new oil. of the proper lubricant, prevent potential over- or un• Acid number. Acidity varies in new unused der-lubrication, track lubricant use and waste, raise lubricating oils based on the concentration of flags about quality (including inorganic contaminaantiwear (AW), antiscuff (EP) or rust additives. tion, debris from wear or lubricant degradation), and Increases above the new oil reference indicate oil contribute to the desired cleanliness and optimized degradation. Lubricants having additives such as performance of machines and systems. zinc dithiophosphate and EP generally exhibit Lubricant analysis can satisfy two primary objechigher acidity than those containing only rust tives: detecting a problem and diagnosing its source. and oxidation additives. Many lubricant suppliers often provide basic lubri• Emulsion. Water separability testing is primarcant analysis as an ily used to evaluate steam turbine, hydraulic added-value service for one of the first steps in establishing an and circulating oils susceptible to high water analysis program for lubricants is to identify using their lubricants. contamination. the lubricant testing technology employed However, the analysis • Foam. In systems where foam is perceived to only may confirm that to make analytical assessments. be a problem, perform a foam test to confirm the lubricant meets whether the lube oil is the source. If the oil isn’t specifications and offer little information regarding the problem, turn your attention to other influmachinery health. For this reason, one of the first steps encing parameters (mechanical or operational) to in establishing an analysis program for lubricants is to resolve the issue. identify the lubricant testing technology employed to make analytical assessments. While laboratory analysis of lubricants can play tooLs aren’t enough an important role in managing machinery assets more As we’ve discussed, you can draw upon many effectively, the good news is that not all testing has to tools to develop an effective CM program. But be performed in a laboratory. Many of the important don’t overlook or underestimate the human faccharacteristics of working lubricants can be examined tor. Routine checks and observations by operators visually or with the aid of very simple tools. and maintenance technicians can yield valuable For example, you can check clarity and water con- subjective data. In addition, consider partnering tamination with a standing sample. A magnet drawn with an experienced specialist; such a firm can up the side of a glass jar containing lubricant diluted add perspective, introduce the latest technology, with a solvent can detect ferrous materials (filings and offer oversight and provide training necessary to metal dust). A bull’s eye sight glass can show flow and maximize results. discoloration. Simple in-plant tools enable viscosity monitoring. These are good day-to-day observations. scott brady is director of marketing for SKF CondiOn a broader and more in-depth scale, you should tion Monitoring, San Diego, Calif. E-mail him at scott. routinely evaluate several critical machine and lubribrady@skf.com. guards, thin panels and pipe work) that “ring” for a long time after being hit. The structure is repeatedly but gently hit; during these impacts a measurement from the accelerometer records the responding ring. Its frequency content then is compared with norms. By identifying a shift in the natural frequency, bump tests can help detect mechanical faults such as cracking in metallic components. (Cracked or poorly bonded structures will exhibit less stiffness, resulting in a change in natural frequency.) The test also can identify weak or unstable structures. JUNE 2008 chEmicalprocEssiNg.com 28 http://chemicalprocessing.com

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Chemical Processing - June 2008 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor Achieve Model Operations Bolster Your Condition Monitoring Toolbox Particle Analysis Makes Solid Progress Improve Batch Reactor Temperature Control Improve Your Job Security Plant InSites Process Puzzler Equipment & Services Product Spotlight/Classifieds Ad Index End Point

Chemical Processing - June 2008

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