A customer of us claimed problems on bearing lubrication on a series of high speed rotating rolls, moreover there were clogging problems on filter elements, even with self-cleaning filters. The plant is very complicated and utilizes a big amount of oil (about 70.000lts). To protect the components, the machine builder opted for very sophisticated self-cleaning filters, very expensive, based on wire mesh filter elements. This systems, born to filter engine oils, hydraulic plants in marine applications and process fluids or water, even if doing correctly their job in the best way possible, just for the use of wire mesh elements, weren’t able to guarantee a satisfying level of cleanliness.