Increasing the lifetime of a belt conveyor

In the processing plants of the extraction and recycling industries, roller bearings face real challenges. The environment is dusty, and the high-powered plant drives are subject to high mechanical stresses such as vibrations and impacts. If roller bearings frequently fail in these conditions, then the situation must be remedied fast.
One case study from NSK’s consulting history: for sizing material, a quarry operator uses a shaker screen that is fed by means of a belt conveyor (Fig.). The tail drum take-up unit, which is located above the screen, is difficult for the maintenance staff to access – but that was where the frequent failures occurred. The causes included extreme dust generation at the screen, which led to the ingress of abrasive dust in the bearing. Another reason was the bearing lubrication, which was only done irregularly on account of the poor accessibility. The basic problem, however, was the use of open-design bearing units. NSK recommended replacing the installed roller bearings with Self-Lube® bearings from its RHP series and the implementation of an improved re-lubrication regime. The ingress of abrasive dust as the second weak point was eliminated with the triple-lip seal of the Self-Lube® bearings for effective protection of the bearing against outside influences. Following the switch, a substantial improvement in the bearing lifetime was registered. While the bearings previously failed every four months on average, the new bearings have already been operating trouble-free for two years now.