Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/136253
amount of contaminants that can be loaded onto the filter before the filter's efficiency is limited. Pressure Loss — This involves the overall differential pressure lost from the filter's placement on the system. The pressure loss will be influenced by the filter media's porosity and surface area. Particle Capture Efficiency — This is the overall effectiveness of the filtration mechanisms within the filter media to extract and retain contaminants from the oil. 61% of lubrication professionals say filter plugging is the failure mode seen most frequently in oil filters at their plant based on a recent survey at machinerylubrication.com System/Environment — The characteristics of the system and environment in which the filter will be installed must be considered, including the contamination expectations, flow rates, location, vibration, etc. Maintaining Installed Filters The best way to prevent filters from reaching their dirt-holding capacity is to avoid contaminants in the system from the beginning. The fewer external contaminants that ingress, the fewer contaminants that are generated internally (particles produce particles). Use the following guidelines to maintain installed filters: • Ensure proper breathers are installed to prevent contaminants and moisture from entering the system. • Keep seals and cylinders clean and dry by using appropriate wipers and boots. • Select the appropriate oil grade and additive package to counter contaminant ingression and internal friction. be similar to throwing away key pieces of evidence. Maintain the filter in the same condition as when it was removed and have it analyzed by the manufacturer or a laboratory. Filter Disposal Oil filters are not designed to be dumped into any wastebasket. Increasing regulations by the Environmental Protection Agency dictate proper filter disposal. While each type of oil filter may have its own requirements, common practices include oil draining, crushing or incinerating the filter. Many disposal services or filter distribution centers will accept used oil filters at little or no cost. References Fitch, E.C., An encyclopedia of contamination control, 1980s Fitch, E.C., "How to Select Fluid Power Filters," The BFPR Journal, 1979, 12, 3, 197-201 Erosion Control, Equipment World Magazine, December 1991 Filtration Manual, PTI Technologies Inc., 1990 Pall Corporation, Ultipleat SRT Filter Brochure, Nov. 2007 Triple R Oil Cleaning Products, Product Brochure, 2013 About the Author Bennett Fitch is a technical consultant with Noria Corporation. He is a mechanical engineer who holds a Machine Lubricant Analyst (MLA) Level I certification through the International Council for Machinery Lubrication (ICML). Contact Bennett at bfitch@noria.com. Analyzing the Filter A filter not only is a trap for the machine's undesirables but also a concentration of clues as to what's occurring within the machine. Particles within the oil may be so highly diluted that practical analysis can become a daunting challenge. However, the particles trapped in the filter may be so plentiful that they can be easily visible to the naked eye. Metal contaminants are a primary indication of an issue within the machine. Although some amount of metal contaminants can be expected, an unusual amount should be recognized by trending the filter's visual appearance after each oil change. Cutting open the filter and suspending a strong magnet over it can aid in pulling out the metal contaminants to more easily distinguish them. If the machine is suspected to have an issue, the filter should not be discarded, as this would www.machinerylubrication.com | May - June 2013 | 53