Split bearings avoid major drives reinvestment at cement plant

Century Cement is part of the Indian BK Birla Group and operates a plant located in Baikunth, in the Indian district of Raipur, producing some 2.1million tonnes of cement per annum. 

The company had been experiencing problems with original equipment white metal bearings on a 2MW induction motor, which were prematurely failing. Indeed, the total life cycle of these bearings was becoming so short, that Century was willing to invest in completely new drive systems, if a lower maintenance, more cost effective motor bearing could not be found.

Initially grease lubricated solid spherical roller bearings were considered; by utilising simple grease lubrication instead of the existing oil recirculation systems, significant maintenance cost reductions could be realised. However, Century was concerned that in the event of a bearing failure the replacement cycle would still involve significant downtime as the motor shaft would need to be decoupled from the raw mill transmission, and lifted to enable bearing replacement to take place.

Instead, UK bearings specialist, Revolvo suggested retrofitting the white metal bearings with its long-life low maintenance SRB split roller bearings. These provide the same grease lubricated benefits of solid roller bearings while offering significantly extended life.

Unlike solid bearings, Revolvo SRB split roller bearings are totally split to the shaft; a design that both simplifies and expedites installation, while significantly reducing the downtime that would be incurred should solid bearings of a similar size have to be replaced.

SRB split bearings allow the shaft to be supported by the lower section of the bearing, whilst the upper section of the housing and bearing outer race can be removed, considerably simplifying bearing inspection, as there is no need to disconnect drives or lift the shaft. This intrinsic feature is especially valuable i8n the case of large rotating machines, where sheer weight and size can be a barrier to fast and effective servicing. Revolvo director, Adrian Menzies, takes up the story:

“When we were approached by M/S Bhavesh Engineering Pvt Ltd to propose an alternative to the OE white metal bearings we were able to show that not only would SRB split roller bearings last longer and require lower maintenance resources, bearing replacement would be far quicker when the time did come for bearings to be changed.

“Once we measured the motor shafts, it was found that where the OE white metal bearings had been in service for over 20 years, some shaft bearing journal wear had taken place, probably exacerbated because of long term lubrication oil contamination, which can often be an issue in cement plants.

“This meant that their motor shafts were out of tolerance for using standard catalogue sized bearings. Fortunately we are able to manufacture entirely bespoke bearings in-house on short lead times, meaning that the replacement project was completed on schedule.”

Since the SRB split roller bearings have been installed the application has run with far greater operational efficiency and economy. Indeed, this initial retrofit has been so successful that Century Cement now specifies Revolvo’s SRB split bearings as their component of choice.