NSK Molded-Oil bearings extend service life in food plant conveyor application

A vegetable processing plant in Germany is enjoying significant benefits following the adoption of Molded-Oil bearings from NSK. Principally, the move has helped the company extend the service life of bearings on a critical conveyor from two weeks, to 40, saving considerable maintenance costs and downtime in the process.

Keen to resolve the question of why its previous bearings were failing at such an unusually fast rate, and eliminate the associated cost and time issues, the company asked NSK to investigate.

During the inspection, NSK experts soon determined the cause. Due to the rigorous hygiene standards demanded by food industry regulations, the system was cleaned thoroughly on a regular basis. However, it was found that the cleaning process prompted considerable quantities of water to penetrate the bearings and, as a result, wash away the lubricating grease.

To help combat the challenges presented by the frequently required wash cycles, NSK recommended the use of its sealed Molded-Oil bearings.

A special tribology concept (tribology is the science of wear, friction and lubrication) has been implemented for Molded-Oil bearings. For instance, the bearings are equipped with NSK’s proprietary oil-impregnated material, which comprises lubricating oil and an oil-related polyolefin resin. This material releases the lubricant, which cannot be washed out due to its consistency, continuously over a long period. At the same time, the carrier material prevents water or solid impurities from penetrating the bearing.

By adopting the bearings, service life at the plant has increased from two weeks to more than nine months. This highly successful outcome once again confirmed NSK’s ´rule of thumb´ that Molded-Oil bearings achieve at least twice the service life of conventional grease-lubricated bearings in water and dust-contaminated environments. In this particular case, service life increased by a factor of 40.

The plant is also experiencing many other benefits. For instance, the operating environment remains clean because no grease escapes and no oil needs to be refilled. Molded-Oil bearings are therefore ideally suited to food industry applications, where thorough and frequent cleaning processes are essential. The use of stainless steel for the bearing components also contributes to this suitability.

NSK supplied the bearings for the vegetable processing plant with highly effective contact seals (DDU) on both sides for even higher levels of protection. This option is available for the standard range of Molded-Oil ball bearings. Molded-Oil is also available on spherical roller bearings and tapered roller bearings.