Each year, approximately 20 sets of bearings had to be replaced due to failures every 4 to 6 weeks. After analysis by NSK, it emerged that the primary cause was water and dust infiltrating the bearings. NSK therefore recommended replacement with Molded-Oil bearings. A test was run and the operating life of the bearings increased to 26 weeks. This significantly boosted the productivity of the manufacturing line, helping the user to save approximately € 9,400 annually in maintenance and downtime costs.
In a final example, a vegetable processing company had installed a biogas plant in order to ferment organic waste from production and transform the resulting methane into electricity and heat for selfconsumption. However, problems had been found with the rotary screen, which filters-out coarse and non-fermenting material prior to the fermentation stage. Failures were occurring repeatedly in the bearings of the rotary screen and disrupting the overall operation of the
biogas plant. Every six weeks on average, the deep groove ball bearings with contact seals had to be replaced. Each rotor has two bearings and there are two rotors per rotary screen. Replacement time was one hour each.
Experts from NSK found that the breakdowns were caused by contamination penetrating the bearing raceways. The customer subsequently followed NSK’ s recommendation to install Molded-Oil deep groove ball bearings made of stainless steel with DU seals on both sides, a move that has led to far fewer replacements.
This yet again confirms one of NSK’ s“ rules of thumb”: in applications where the environment is contaminated by moisture and dust, the service life of Molded-Oil bearings in stainless steel is more than twice that of bearings with conventional grease lubrication.
pilath-m @ nsk. com www. nsk. com
36 FDPP- www. fdpp. co. uk