Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/704613
directly impacts the lubricant's health and how often the oil must be changed. There is even some environmental impact associated with excessive foaming. If the oil level cannot be managed, it can lead to spillage as foam seeps out of open hatches, breather ports or seals. The oil then becomes a risk to personnel who could slip, trip or fall. It also becomes a hazard if it gets into a sewer system that is not contained to the plant. If this happens, not only must some type of secondary contain- ment be placed around the machine to contain the spill, but action should be taken to correct the problem causing the foam. Removal by Filtration Studies have directly linked lubricant foaming issues with defoamants being stripped due to filtration. Indeed, it is possible to filter out these additives, and if they are no longer in the oil, they will not provide any benefit. Unfortunately, there is not a one-size-fits-all approach to ensure filters aren't impairing additive levels, since there is variability in the formulation and concentration of defoamants required for equipment. With standard depth media, there is inconsistency in the filter's pore sizes. This allows certain additives to make it through while others are removed. Much of this will depend on the filter's average pore size and how efficient it is at the selected micron size. Some defoamants aren't solid and can even squeeze through smaller pore sizes. How to Properly Size Filters According to filter and lubricant manu- facturers, defoamant filtration is most common when oil is "overfiltered" or when the selected filters are too aggressive for the fluid they are charged with decontami- nating. While overfiltering can occur, it is rare. Most industrial facilities underfilter their oil or do not filter it at all. To choose the proper filters for your equipment, you first must set the target cleanliness level. Once the target cleanli- ness has been set, you can identify a suitable filter to achieve that level. When in doubt, ask the oil or filter manufacturer for specifications. The general consensus among oil companies is that the biggest risk of filtering out defoamants begins at the 3-micron level. The most widespread application of this type of filtration is in hydraulic and turbine systems, which demand the most stringent cleanliness. Gear systems usually don't require super-clean fluids and thus don't need this fine level of filtration. There- fore, it is important not only to consider machine requirements but also the ability to filter oil to this level without damaging additive levels. How to Monitor If a defoamant is silicon-based, it can be monitored through normal elemental anal- ysis of the oil sample. When silicon levels drop, you know the additive is being depleted. The best way to monitor organic additives is to conduct performance testing such as the foam stability or foam tendency of the fluid. By comparing these results against new oil, you can judge the additive's ability and function. Of course, checking for signs of foam in your daily inspection of equipment level gauges will offer the best indication of any potential issues. Given proper attention and care, defoamants can work well for your equip- ment and lubricants. Just be sure to size filters accordingly and routinely monitor additive levels to ensure they are working properly and staying healthy. About the Author Wes Cash is a senior technical consultant with Noria Corporation. He holds a Machine Lubrication Technician (MLT) Level II certification and a Machine Lubricant Analyst (ML A) Level III certification through the International Council for Machinery Lubrication (ICML). Contact Wes at wcash@noria.com . www.machinerylubrication.com | July - August 2016 | 49 65% of lubrication professionals report that foaming has been a problem in the oil at their plant, based on a recent survey at Machinery- Lubrication.com