By Jim Fitch
Machinery Lubrication Magazine

Do you really know how your lubricants become contaminated? Have you taken an inventory of the sources of contamination and the primary points of entry? If not, you are in the majority as sadly, few organizations go to the trouble of performing a contaminant ingression study.
For many machines, the exclusion of contamination is the only way to control contamination. This is because these machines either have no filter or the filter in use is coarse, providing no practical protection in the particle size range of critical oil films.
When particles are not removed by filtration or by settling, a lubricant’s contaminant level equals the machine’s service hours multiplied by the number of particles ingressed per hour (ingression rate). For machines exposed to high ambient dust, particle counts can exceed recommended levels in just a few hours. After days of exposure, an oil can turn into more of a honing compound than a lubricating medium.