Up Time Magazine- February/March 2008

lubrication upload Here To Stay Sensors Are Changing the Lanscape of Oil Analysis by Jack Poley & Michel Murphy A couple of decades ago, when the notion of on-line monitoring of lubricating fluids was in its infancy, we were predicting that sensors, in one form or another, would eventually prove practical and effective for real-time monitoring of lubricants. While we were off five years or so about the timing of their arrival, continued perseverance, research and development has made the dream a reality at this point. Today, there are several viable products available on the market, covering many different parameter measurements. decision-making, including oil drains and filter changes. Generally, sensors primarily address contamination and degradation of lubricants, which often suggest that operational problems need to be addressed (see Figure 1). Wear is also tackled by sensor technology. Total particle counting is readily available, but does not distinguish between wear or contaminant particles. But several ferrous particle sensors exist (see Figure 2), some able to show distinction between ferrous and non-ferrous particles, which is very promising and already proving useful. Resolution of particle size detection is continually improving so that beginning stages of wear can be identified early enough to be significant. Still, it will take more than a distinction between ferrous and non-ferrous to provide adequate information on wear metals, such as can be routinely determined in today’s oil analysis laboratories. Therefore, spectrometric analysis may be one of the last ‘common’ tests supplanted by sensors, should this development eventually prove feasible. Regardless of the timing of sensors’ inclusion in the manufacturing of equipment, it will be a gradual process. Some customers will take more risk, allowing sensors to dictate much of their maintenance actions, but most, in order to clarify the situation, will probably send samples to a laboratory when abnormal readings are observed. Still others will continue to routinely extract and send lube samples to laboratories, preferring to use sensor data as early-warning indicators, supplementing visual and aural observations on site, but not necessarily serving as maintenance drivers unless the added information from laboratory testing is also available. New equipment being manufactured offers the opportunity to build-in sensor technology at the lowest expense and intrusiveness. Retrofitting will be possible in some cases, but will not be feasible in others. Physical constraints may be an issue, and remaining component life cycle cost may also influence a retrofit decision. Finally, there will be some who prefer to continue collecting samples as usual. There is no doubt that lubricant-monitoring sensors have begun to play a significant role in oil analysis. With recent advancements in technology development, sensors have begun to be economically feasible for installation on new equipment as well as some retrofitting of inservice components. There are four main drivers for the development of sensor technology: • Reduced long-term costs for test data acquisition [e.g., wireless technology] • The desire/need for instant, frequently updated information • Issues regarding collecting and sending samples anywhere due to costs and disposal issues • Time delays (both real and perceived) in receiving test results Over time, these drivers have spurred continuing research and development until cost/effect ratios have begun to make sensors a viable aspect of maintenance strategies. While it will be quite some time before sensors can match up directly with laboratory testing, the gap will surely be narrowed with the march of time. Sensors have shown the ability to detect: • • • • • Moisture • Oxidation Viscosity • Strong Acids Additive Depletion • Total Particulates Ferrous Particulates • Soot (diesel engines) Fuel Contamination (diesel engines) Some sensors determine dielectric strength or conductivity properties of the oil. While changes in these properties suggest possible problems (contaminants), there is usually no way to determine which of several possibilities is indicated, unless additional testing (at a lab) is accomplished. Until such ambiguity is overcome, the laboratory will always serve a purpose. It is expected that sensors will replace some, but not all, of the routine tests currently utilized. The readings will be accurate, or at least specific enough, for basic 34 february/march 2008

Table of Contents Feed for the Digital Edition of Up Time Magazine- February/March 2008

Up Time Magazine- February/March 2008 Contents Upfront Upclose: Lessons Learned from the Walter Reed Story Information Technology: Parenting and Asset Performance Infrared: It's Alive! Lubrication: A Sense of Change Maintenance Management: PdM, Standardized Motor Testing: Being Well Connected Precision Maintenance: How to be Marketable Reliability: The Voyage of Wells Dairy Ultrasound: Two is Better Than One Vibration: Diagnosing a Cracked Shaft Upgrade: A Different Kind of Journey

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