Posted to News on 14th Dec 2021, 00:00
Bearings address long-standing challenge in the mining industry
Many conveyors operating in the hostile environment of a mine suffer from the premature failure of bearings on the head, tail, drive and tensioning pulley. There are numerous reasons why overcoming this issue has proved challenging over the years, but NSK says it has come up with a solution that improves service life by up to 20 times without comprising any other requirements.
To allow important accessibility, the head, tail, drive and tensioning pulley on mining and quarrying conveyors traditionally relies on open bearings. However, the short service life of these bearings frequently threatens the uptime of operations. These bearings typically suffer from hard particles (dirt, dust) and water penetrating the housing seals and entering the open bearings. As well as improving the sealing situation, any new solution would have to avoid compromising important user requirements, one of which is rapid mounting.
NSK’s solution includes a detachable seal. This concept centres on a seal mounted to a ring/holder that is fully detachable (via bolts), thus providing access for clearance measurements using feeler gauges (as well as the end user’s ability to select and pack their choice of grease at commissioning and re-grease if required). The NSK design requires no heat-shrink equipment and continues to make use of ISO-standard tapered adapter sleeves and locknuts, thus offering interchangeability with existing solutions.
Importantly, despite the addition of the detachable seal, there is no extension of the ISO-specified boundary width dimension, therefore permitting the use of standard bearing housings. NSK achieved this outcome by deploying its proprietary, independently certified Hi-TF/Super-TF bearing material to mitigate the design constraints of the seal.
This material is claimed to increase the load rating by up to 10% (depending on size) in comparison with a standard open bearing, allowing the solution to remain within the same dimensional envelope. Mining companies can therefore quickly and simply swap their existing open bearings with the NSK solution; there is no requirement for a new housing.
As a point of note, Hi-TF and Super-TF bearing material is claimed to provide twice the service life of conventional bearing material when operating with clean lubrication, and up to 10 times when operating with contaminated lubrication.
NSK’s solution also features proven heavy-duty nitrile (HNBR) seal technology capable of operating up to 100°C, providing 30% more effective sealing than standard industry concepts thanks to the use of spring-loaded lip technology. This design helps to deliver protection from contaminants and long service life.
