Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/778560
4 | January - February 2017 | www.machinerylubrication.com AS I SEE IT 3. Water Contamination: Cloudy oil, free water in BS&W bowls, rust on the corrosion gauge, hydrated desiccant breather, entrained air problems, positive result from a crackle test 4. Excessive Wear Debris: Metallic sedi- ment in BS&W bowls, laser pointer inspection, loaded magnetic plug, metallic debris on the filter's surface, magnet inspection of oil sample 5. Aerated Oil (Entrained and/or Foam): Sight glass inspection (cloudy or frothy oil), sudden rise in the oil level, hatch inspection, rise in the oil temperature, emulsified water 6. Overextended Oil Drain: Sight glass inspection (dark, sludgy oil), dirty oil (see No. 2), excessive wear debris (see No. 4), soft insolubles on blotter, air-handling problems After each inspection (that passes), the inspector should have a high level of confi- dence that there are no active or abnormal C&S conditions related to the oil or machine. This is done by skillful inspection in search of the COS. If you engineered your inspection protocol properly, it would be extremely difficult for there to be an active C&S in progress without a positive alert from an inspection of each of the COS. These critical occurrence states are designed to effectively reveal C&S events. Routine Inspections A routine inspection consists of quick and frequent inspection events not gener- ally requiring the use of tools, pulling a sample or special inspection aids. The following are examples of routine visual inspections related to lubricating oil: Oil Level — Visually inspect the dipstick, level gauge or sight glass. Oil Color and Clarity — This involves a sight glass inspection aided by a strong light. Usually a comparator image is used. Foam Presence and Stability — This can be determined by some sight glasses or headspace inspections, or both. Entrained Air Presence and Stability — Also generally assessed by sight glasses and headspace inspections. Free Water — Inspect water traps or BS&W bowls for a free water phase. Emulsified Water — Inspect sight glasses for turbidity. Oil Sediment and Floc — Inspect sight glasses and BS&W bowls for stratified solids and soft insolubles. Gauge and Sensor Inspections — These inspections utilize various digital and analog gauges, including temperature, pressure and flow. Some machines have sensors that report oil properties, such as particle count, wear particle density, water contamination and viscosity. Heat Gun Inspection — This provides a quick, quantitative assessment of the oil temperature on critical machine surfaces. Magnetic Plug Inspections — Some sight glasses have integrated magnetic plugs for quick and effective observation. Headspace Inspection — Hinged hatch access aided by a strong light can enable obser vation of bathtub rings, varnish and foam. Corrosion Gauge Inspection — Similar to magnetic plugs, these gauges can be quickly inspected to reveal corrosive condi- tions associated with corrosion agents, impaired rust inhibitors, etc. Leakage Inspection — Failed seals and radial shaft movement can cause leakage, but this can also be due to a sudden drop in oil viscosity, change in oil chemistry or ingression of certain liquid contaminants. Exception Inspections Exception inspections are conducted either because of a reportable or question- able routine oil inspection or as the result of an abnormal operating condition. Most exception inspections require the extraction of an oil sample and a simple test that can be performed at the machine or on a benchtop. The following are examples of visual exception inspections related to lubricating oil: Blotter Spot Test — This simple test can be extremely helpful for detecting a range of contaminants and abnormal oil conditions. Blender Test — This test can be performed with a blender or graduated cylinder. It is useful for revealing certain contaminants, degraded oil chemistry, impaired air-handling ability and other abnormal conditions. Inverted Test Tube — This is an old method that uses the rate of rising air bubbles to roughly estimate oil viscosity. Graduated cylinders or sample bottles can be utilized as well. Oil Drop on the Surface of Water — Certain additives and chemical contaminants influence the interfacial tension of lubricants. Placing a couple drops of oil on the surface of water can quickly exhibit this. Compare the results to that of new oil. Cold Oil Turbidity — Oil with trace amounts of water can be assessed by placing a sample of the oil in a refrigerator for an hour. Dissolved water will saturate in oil at cold temperatures and become visibly noticeable by a cloudy appearance. Hot Oil Clarity — The presence of soft oil insolubles (oxides, organic materials, dead additives, insoluble additives, varnish poten- tial, etc.) and some emulsified water will often quickly dissolve in the oil when heated. This is visibly noticed by the oil becoming markedly clearer (less turbid). Crackle Test — This well-known test for water contamination can be performed with a hot plate or soldering iron. Bottle and Magnet Test — The pres- ence of ferromagnetic wear debris particles 70% of lubrication professionals perform daily visual inspections of the oil at their plant, based on a recent survey at MachineryLubrication.com