Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1103301
42 | March - April 2019 | www . machinerylubrication.com Water is an important resource in many production pla nt s as well as a natural element in the environment. However, it is also an undesirable contaminant when present in lubri- cating oil or grease. In fact, water is the second most common lubricant contaminant and can cause a signifi- cant reduction in the life of machines and components. erefore, it is crit- ical to monitor water contamination to ensure machine reliability. A number of different approaches can be used for monitoring mois- ture contamination, depending on the machine's criticality, the risk of failure and the available resources. ese methods include laboratory oil analysis, portable field instruments and tests, visual field inspections, and online sensors. Laboratory Oil Analysis Although laboratory oil anal- ysis remains the most frequently used method of monitoring water contamination, it doesn't neces- sarily represent the most effective approach in terms of early failure detection. With this method, oil samples are taken and shipped to an external laboratory to perform an agreed-upon test slate. This may also include an occasional or exceptional sample of new or used oil being sent to the lab for a specific purpose, such as quality control of the incoming lubricant or when an issue is suspected. While this approach is useful, the time from when the sample is taken until the report is read can be a limitation, especially if an abnormal condition is present. Among the technologies that laboratories employ to monitor mois- ture include Karl Fischer titration, Fourier transform infrared (FTIR) spectroscopy, relative humidity sensors and distillation. Karl Fischer Titration Karl Fischer titration is the preferred test due to its accuracy and consistency. ASTM D6304 is currently the recommended method. Results are reported in parts per million (ppm) or percentage of water. For high-viscosity lubricants or formulas containing sulfur and other compounds, the test results will be more precise if a vaporizer is used to remove water from the sample. Water may also be dissolved in toluene. is additional step is known as co- distillation. Errors due to the presence of certain additives without vaporization may be 50-100 ppm. Of course, no laboratory test method is perfect, so some vari- ability in the results can be expected. ASTM methods typically report the variability of each test in terms of repeatability and reproducibility. Karl Fischer titration is no exception. Modern Methods for Monitoring Water Contamination Water is the second most common lubricant contaminant and can cause a significant reduction in the life of machines and components." " Water in O il PERSPECTIVE Alejandro Meza | Noria Corporation