By S. Gebarin & Jim Fitch
Practicing Oil Analysis Magazine
Spherical particles have been found in microscopic analysis in many different machines. The phenomenon of perfectly round spheres has been a topic of interest since their discovery and a number of theories have been formulated for their origin.
While more than one theory exists, their source can be narrowed down by considering certain factors such as particle size and texture, equipment type, surrounding debris, stage of equipment life and environmental conditions. Table 1 summarizes the predominant theories of the origin of spheres in oil analysis.