Machinery Lubrication magazine published by Noria Corporation
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64 Machinery Lubrication Annual Edition | www . machinerylubrication.com You can also determine compatibility based on the OEM and industry specifications. Certain specifications stipulate that oils must pass compatibility with different additive types of the same or related specifications. API and Caterpillar TO-4 are examples of specifications that allow mixability between oils within the same specification. If unsure or insufficient information cannot be provided by your oil supplier, it is best to assume they are incompatible. is warrants compatibility tests to determine that the two oils combined will not undergo prop - erty and performance changes, leading to them becoming inferior to the individual oils. Mix the new and current virgin oils in three ratios, 90:10, 50:50 and 10:90, to simu - late different mixing conditions. Heat the mixtures to 65⁰ C continuously for seven days while observing any change in appearance and sediment fallout. A clear indicator of incom - patibility is deposit formation that will plug filters and hinder oil flow. e absence of changes in the appearance does not mean the oils are 100% compatible. Critical machines such as turbines will require further tests to ensure no performance degra - dation is taking place during service. Some of the follow-up tests recommended are Kinematic viscosity at 40degC (ASTM D445), Acid number (ASTM D664 or D974), foaming characteristics (ASTM D892), air release properties (ASTM D3427), water sepa - rability (ASTM D1401) and rotating pressure vessel oxidation test (ASTM D2272). If any of the new lubricants are found to be incompatible, steps need to be taken to mini - mize contact with the current lubricants during transition. Airtight lubricant change-out procedures must be in place to eliminate any possibility of mixing incompatible fluids when - ever practical. For example, storage tanks and machine compartments need to be flushed and cleaned before filling with the new lubricants. Application Risk Application risk involves maintenance staff applying the wrong oil due to unfamiliarity with the new lubricant naming and packaging. is mistake can be catastrophic. Proper management of change process is key to managing the transition. One person should be assigned as the overall champion or project manager to handle the change process from start to finish. Involve the oil supplier and all stakeholders within your plant to get their input. We do not want to have change- over issues due to an oversight. Communication is paramount. All users, especially personnel who receive, store, transfer and fill lubricants into machines should be made aware of the changes. Easy-to-under- stand procedures and instructions will greatly aid in making the changeover seamless. One important tool is a cross-reference chart. It shows the current and new lubricants side by side and the machine compartment they should go into. To avoid confusion, it is preferable that the project manager goes through the chart with the relevant staff to ensure everyone understands. is allows questions to be asked and addressed earlier rather than later. The cross-reference chart must also be accessible and clearly displayed in areas where lubricants are handled whenever practical. The lubricant storage area and all dispensing and filling points must be clearly labeled with the new lubricant's name along- side the old lubricant's that is being replaced. Once the transition is over, the old lubricant label should be totally removed from the plant. Maintenance documents, such as the service sheet, will need to be updated with new oils as old ones are discarded. During the transition period, you will have to stock both old and new lubricants at the same time. All old lubricant packaging and containers need to be marked for depletion and stop order once finished. Here, 'First In, First Out (FIFO)' must be strictly in place. We do not want to find unopened or unused packaging of old oil in the plant midway through the transition when all the machines are already filled with the new oil. Even worse, someone may unintentionally re-orders the old lubricant when change is underway, thinking it is low in stock. is is a common mistake and can easily happen in your plant without the adequate training on proper lubricant replacement. If you have an oil analysis program in place, the laboratory needs to be informed of the change. Oil properties, additive compo- sition and concentration may be slightly different. is could cause a false alarm when the readings turn out differently from the old oil's reference. For example, some engine oils use contains more magnesium concentration as a detergent than others. is can be mitigated by supplying the new oil sample to the lab for testing and recording the readings as a new reference. When these three risks are managed prop- erly, companies will find minimal disruption to their operations during a lubricant change. Although there may be teething problems, the long-term benefits of having improved lubricant quality, performance, and service far outweigh all the potential hurdles. ML About the Author Aaron Said is the head of technical at International Lubricant Distributors (ILD) in Australia. He is focused on developing and delivering reliability improvement through lubrication excellence for ILD clients. His aim is to drive competitive advantage through the effective and optimum use of lubricants and their condition monitoring. Alongside 20 years of experience in lubri- cants, he is a Certified Lubrication Specialist and Oil Monitoring Analyst from the Society of Tribologists and Lubrication Engineers (STLE). Other credentials include Machine Lubricant Analyst I & II and Machinery Lubri - cation Engineer (MLE) from ICML. He holds an MBA, MSc in Aeronautical Engineering from Imperial College London, and a Mechan- ical Engineering degree from the University of Sheffield in the United Kingdom. LUBRICANT PROPERTIES