Wälzlager - 2012-01-09
NSK's Asset Improvement Programme (AIP) has achieved 10- times bearing life and saved €2,970 annually on downtime and maintenance costs for a major company in the Quarrying & Mining industry that was experiencing frequent reliability problems with casting units assembled into a vibrating drum.
The reliability problems were resulting in bearing failures every 2-months, or 440 hours of operation. They were caused by the severe environment in which the casting unit support bearings operated. The environment was wet and mechanically demanding. Worse still, the bearings were often exposed to large amounts of sand, which often covered them completely resulting in harsh abrasive ingress, and subsequent premature failure.
In addition to the problem of regular bearing failures, there was another issue, in that the bearings were difficult to access, making replacement difficult. This complicated maintenance, making it a major issue, with annual costs, including downtime, totalling at €3,300 per year on just this one installation alone.
The ongoing cost and the sheer difficulty in maintaining the vibrating drum bearings meant that a long term solution to the failure problem was required. Engineers from NSK were called in to look at the installation and provide a resolution.
The engineers visited the site as part of NSK's AIP programme, which is designed for end-user bearing customers in the quarrying industry that are looking for more than just product supply. Rather, they are looking for a value-added service that actually helps them to reduce operating costs, improve efficiency and profitability. These objectives are achieved by delivering tangible savings to assets, such as equipment and machinery, and also by improving the working knowledge of maintenance and engineering personnel.
In view of the difficulty of the operating environment, the NSK engineers proposed using Self-Lube® Triple Lip Seals on the vibrating drum bearings. These seals provide maximum protection in applications having the highest degrees of contamination.
The Triple Lip seal consists of a one-piece moulded nitrile seal with three sealing lips, bonded to a protective steel outer pressing, which is robustly secured in the outer ring of the bearing. This arrangement delivers a highly efficient sealing arrangement for use in the worst types of operating environment.
The effectiveness of the Triple Lip Seal solution has been evidenced, subsequently, with no failures in the 19 months, or 4.400 hours, of operation since the seals were fitted. This has had a substantial effect on maintenance costs at the quarry, with annual costs for routine maintenance and downtime now calculated at just €330 producing an annual overall saving of €2,970 that goes straight to the quarry's bottom line.