Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1148092
16 | July - August 2019 | www . machinerylubrication.com maintenance decisions before damage occurs. New sensor technologies utilize electrochemical impedance spectroscopy (EIS), which covers a broad spectrum of oil properties and enables sensitivity to most failure modes. In Figure 1, an online oil-quality sensor was installed on a diesel engine operating in off -highway conditions. After an oil change, there was a break-in period, and the oil-quality reading peaked for that cycle. As the engine continued in operation, the sensor readings trended down as the oil quality degraded. While in operation, the engine developed a coolant leak that would have gone undetected and severely damaged the equipment, forcing a full engine rebuild. Upon a signifi cant break in the oil-quality trendline and an increase in relative humidity detected by the sensor, an inves- tigation discovered the coolant leak. e equipment was repaired, and the oil was changed and put back into service with minimal downtime. Oil Drain Optimization Optimizing oil drains is another important benefi t of oil-quality monitoring. Unlike previous generations, the newest sensors can track and trend most of the major indicators for condemning the oil. Figure 1 off ers a good example of a normal trendline: e oil has a break-in period, peaks and then degrades over time. is degradation of the trendline lets you predict when condemning limits will be crossed, allowing the oil's remaining useful life to be forecasted. Being able to not only detect when oil changes are required but also to predict the oil's lifespan is a major enabler for oil drain optimization. In Figure 2, an operator installed an oil-quality sensor on a piece of mining equipment to monitor oil changes. Upon review, it was found that the oil changes were occurring on average at around 25 percent of the total remaining useful life. is left approximately 75 percent of the oil's life unused. In most cases, the oil was changed before it had even been broken in. By using the data provided by the online sensor, the operator was able to change the drain interval practices from being based on the number of in-service hours to being condition-based. is has led to a savings of nearly $40,000 per asset per year through decreased oil consumption while signifi cantly reducing downtime and environ- mental waste in the process. Additional Improvements New sensing technology is just now starting to reveal all the ways that it can help reliability programs. As the use of these sensors increases, more improvements can be expected, from optimizing top-off s and bleed-and-feed methods to advanced fi ltration, additive replenishment systems, etc. For now, these early wins are driving adop- tion at a signifi cant rate by changing the way best-in-class reliability programs operate. ML OIL ANALYSIS Figure 2. Readings from an oil-quality sensor used to monitor oil changes on a piece of mining equipment