Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/520842
8 | May- June 2015 | www.machinerylubrication.com Trending Data In the next iteration of the oil analysis program's evolution, trending becomes a part of the analysis. No longer are you only looking at the report sitting in front of you, but now you are taking into consideration the history of the data. The best way to trend oil analysis data is to follow its movement visually using a standard trend plot. Trending can quickly reveal the rate of change over time (slope on the plot) associated with a series of monotonic data points that might reveal a reportable condition. It can sometimes be concluded that if the rate of change is normal and constant (linear trend slope), the lubricant and machine conditions are equally normal and acceptable. However, abnormal or unhealthy conditions do not always produce steep trend lines. Trending is a valuable tool to add to your oil analysis program. It is often overlooked in favor of a quick glance for abnormal results on a single, current report, but in doing so, much of the value of oil analysis is lost. I'd like to propose a different type of trending. Instead of trending oil analysis reports from the same oil and same in-service machine, I'd like to see trending with a focus on the life cycle of the lubricant while onsite. This would require the fi rst sample being taken when the drum arrives onsite. There are multiple reasons for this, including the example I'll use going forward: contamination. The effect that particle contamination has on machine reli- ability has been proven over and over in a number of case studies. It only makes sense that you use this knowledge to your advan- tage and employ cleanliness as a key performance indicator for your program. Imagine a plot of ISO cleanliness over the life cycle of the lubri- cant. Usually the lubricant arrives too dirty for use in the equipment straight from a sealed drum, so it must be cleaned. This means your plot would start with a high point and slope down as you cleaned the lubricant while in storage. If your plot levels out from there throughout its lifespan, you have done a good job at contamina- tion control. However, if there is an upward spike when you take an oil sample after the machine component has been fi lled, you may want to check your handling practices. If you notice the plot starts high as new oil, dives down after you clean it up, stays there until it is put into service in the component and then gradually climbs, this tells you that you have an ingression point at the point of use. When oil analysis data is used in this way, it makes it very easy to determine where you need to spend your time, money and energy to improve the process and also your machine reliability. A number of scenarios could exist. The following are some of the most likely (as shown in the graph above): A. The fl uid arrives from the distributor dirty and is cared for in terms of contaminant ingression, but at no point in the process is the fl uid ever cleaned. This results in high ISO particle counts in the machine, which ultimately affects reliability. B. The fl uid arrives dirty, and an effort is made to clean the fl uid while in storage. It is kept clean during storage and is cleaned further upon application. The machine is modifi ed to exclude particles but not remove them. C. The fl uid arrives moderately dirty and is cleaned. It is kept clean in storage, but the handling practices are lacking. Once the lubricant makes it to the machinery, the machine is modi- fi ed to be able to remove the solid particles. D. The fl uid arrives clean but through poor storage and handling reaches the machine very dirty. The machine is then modifi ed to be able to remove these newly ingressed particles. Because of the effect particle contamination has on equipment reliability, you can see how this data can be used to help drive deci- sions on where in the process you need to focus. This is essentially where oil analysis earns its keep. It is a means by which you can make better informed decisions about your machinery, your prac- tices and ultimately your business. About the Author Jeremy Wright is the vice president of technical services for Noria Corporation. He serves as a senior technical consultant for Lubrication Program Development projects and as a senior instructor for Noria's Machinery Lubrication I and II training courses. He is a certifi ed main- tenance reliability professional through the Society for Maintenance and Reliability Professionals, and holds Machine Lubricant Analyst Level III and Machine Lubrication Technician Level II certifi cations through the International Council for Machinery Lubrication. Contact Jeremy at jwright@noria.com. Reception Storage Handling Application In Service Lubricants Life Cycle A B C D Cleanliness