Almost all machinery that moves requires bearings. However, they are liable to degradation over time. Bearings will fail for a number of reasons but the key take away is that ALL bearings will degrade at some point and if they are left unchecked, maintained or replaced WILL fail. Knowing the root cause of damage can help prevent future failures. According to ISO 15243, damages left undiagnosed can actually mask the underlying cause if left too long. Most decay in bearing quality occur when lubrication has been used up in the bearing. Identifying when this happens and refilling the oil in the bearing a key way of extending life span.
Where are bearings used?
Below are a few examples of the industries and applications in which bearings are present. Many industries have machinery that requires some form of motion enabled by bearings.
Steel production facilities e.g. Cold rolling mill machinery. Mining industry e.g. Machinery such as crushers, stackers, conveyors, vibrating feeders, magnetic separators, slurry and vacuum pumps, classifiers, agitators and compressors. Paper processing industry e.g. Rolls, roll alignment, balance, and the condition of the electric motors and gearboxes. Cement industry e.g. Mills, separators, roller presses, separators, conveyors, feeders, air compressors and fans. Thermal power industry e.g. Gas and steam turbine generators Maritime industry e.g. Diesel engines, gas turbines and nuclear reactor powered ships utilise bearings in all areas, from crankshafts to pistons and pumps.
Case study of bearing failure:
On 7 March 1997, the Polish flag general cargo vessel Lodz 2 was using one of its own cranes, discharging a general cargo of steel products, including bundles of steel pipes, from no. 2 hold and tween deck. The load, weighing approximately 8.6 tonnes, consisted of 18 lengths with diameters varying up to 273 mm. As the load reached the side of the ship, there was a violent jolt and a bang as the slew bearing failed, then the crane fell from its pedestal into the port tween deck of no. 2 hold. The crane was severely damaged and the badly twisted jib had to be cut up to remove it from the ship.