Particulate impurities in oils and lubricants

Solid materials or particle contamination in lubricating greases have a significant influence on the operating life of rolling bearings, which is why increasingly higher demands are being placed on the cleanliness of lubricating greases. The quantitative determination of the content of solid substances above 25 µm particle size is carried out by CleanControlling according to DIN 51813 by means of high-pressure filtration and washing out with a solvent mixture.

The analysis of particle loads in used greases provides information for conclusions on the wear behaviour of rolling bearings. In conjunction with the microscopic analysis method based on cleanliness inspections of technical cleanliness, the results are particularly informative from a particle size of 25 µm or, alternatively, as from 10 µm, since the particle occurrence is completely measured, counted and classified according to shiny behaviour such as "metallically shiny" and "non-shiny" and documented with particle images of the largest particles. An essential step before microscopic analysis is the dissolution of the consistent greases with a suitable, tempered solvent mixture and subsequent analysis filtration.