Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/359954
ML By Bennet t Fitch, noria corporation lessoNs IN lUBrICAtIoN How often should I take an oil sample? From which machines should I sample? These are typical questions I'm asked when visiting plants during the development of a lubrication program. While they are good questions, I always follow up my answers with an explanation of why effective oil analysis requires consideration of several important factors. If one of these factors fails, then the entire oil analysis program will likely fail as well. This article will describe each of these key factors, which form a chain of success for oil analysis optimization. The three main elements in this chain involve obtaining a representative oil sample, ensuring reliable testing and determining the optimum course of action. As the illustration on the next page suggests, each link in the chain relies on those above it. If a link fails (becoming the weakest link), then all the links below it are compromised. Obtaining a Representative Oil Sample Select the Right Machines for Oil Analysis Each sample obtained for oil analysis can be costly, so sampling every machine in a facility with thousands of lubri- cated machines is not feasible. The best method is to determine the Overall Machine Criticality (OMC) and the Overall Lubricant Criticality (OLC), which are based on machine and lubricant failure causes in terms of probability and severity. Takeaway: Sometimes just one finding, such as the discovery of elevated wear debris levels on a critical machine, can justify the cost of the oil analysis program. If money is spent for oil analysis on every machine or machines are poorly selected for oil analysis, these returns may not be realized. Clean and Correct Sampling Containers and Extraction Tools One of the main objectives of oil sampling is minimizing data disturbance. Using the right sampling tools and ensuring their cleanliness will be vital. Oil sampling bottles should be certified to one of the three cleanliness levels: clean, superclean or ultraclean. As for extraction tools, nothing in the fluid's pathway from the machine to the bottle should further contaminate the sample and disturb the data. Takeaway: In oil analysis, it only takes a small amount of contami- nation to cause concern. If the sample becomes further contaminated during the sampling process, the results can trigger premature cautionary or critical alarms. Correctly Located Sampling Ports and Sampling Frequency The precise location where an oil sample is extracted must be carefully chosen so the analysis results will be representative of the oil in the machine's wear protection zones. Two samples taken from the same machine but in different locations can potentially have different results for tests such as particle counts, elemental analysis and Fourier transform infrared (FTIR) spectroscopy. Similarly, the Follow the Chain of Success for Oil Analysis Optimization Sometimes just one finding, such as the discovery of elevated wear debris levels on a critical machine, can justify the cost of the oil analysis program. 12 | July - August 2014 | www.machinerylubrication.com