Downtime is the enemy of quarry/mine operators and construction project managers. Critical plant and equipment must offer reliable performance to meet demanding output targets, project deadlines and budgets. Whether extraction, transportation, preparation, separation or enrichment, these processes are subject to contamination and debris, not to mention heavy loads, shock loads and vibration. Bearing selection is vital to ensure long service life. Getting it right means that mining and construction sites can maximise their uptime and productivity while simultaneously reducing maintenance costs.
Leveraging state-of-the-art design, material, lubricant and seals, NSK Self-Lube® bearings exceed the life of conventional bearings. Furthermore, by selecting Self-Lube® bearings with triple lip seal and shaft end protectors, it is possible to reduce the costs associated with downtime and repairs. NSK recommends its specially developed triple-lip seal for applications with a high degree of contamination. Bonded to a protective outer steel pressing (secured in the outer ring), this one-piece moulded nitrile seal with three lips makes for a highly efficient sealing design that protects the bearing in severe operating environments.
The combination of easy use, self-lubrication and long service life mean that increasing numbers of companies in the quarrying, mining and construction sectors are now reducing their costs for replacement bearings, maintenance and downtime. A case in point involves a company that was experiencing frequent reliability problems with the bearing units assembled in a vibrating drum. These bearings work in severe environments, where they suffer exposure to sand that often wholly covers the units. In addition, due to the nature of the application and its difficult access, the regularity and increasing cost of maintenance was proving an issue.
In another customer success story, a company supplying ready-mixed concrete and other construction materials invited NSK to perform an application review of its augur screw pump bearings. The augur pumps transfer ash (an abrasive mixture of ash, sand, glass, fibres and metal grit) into waiting containers. Here, the screws lift the ash at an angle of approximately 40 °, where the lower bearing units frequently fail. Upon examination of the failed bearings, NSK was able to identify several issues. For instance, after removing the flinger seal, it was evident that no contact seal was running against the inner ring of the bearing. It had likely worn away, and there was now a direct contamination path into the bearing. Further problems included heavy cage corrosion and the absence of lubrication. The ingress of fine dust and particulates had probably soaked up any grease and created a grinding paste, eroding the rubber seal.