Following the successful installation of a LORD Fan Balancing System on the preheater ID fan at their Dunbar Works in Scotland, Lafarge Cement UK has opted to install the system at three additional plants located in the United Kingdom.
Orders have been placed for installation during the Spring 2007 outages at Cauldon, Hope and Aberthaw works. LORD Corporation, in partnership with their UK distributor, T.E.V.A., will work with Lafarge Cement to install and commission these systems in an effort to reduce unscheduled downtime due to high fan vibration.
Lafarge Cement integrated the LORD balancing system into their operation at Dunbar Works early in 2006 after experiencing vibration problems and unscheduled shut-downs that resulted from their efforts to increase capacity the previous year. An unexpected side effect of the capacity modifications was a severe material build-up and associated excessive vibration levels on the preheater ID fan. The result was build-up on the fan blades, up to 50-mm thick, forcing Lafarge to make several unscheduled shut-downs for cleaning of the rotor. Nearly100 hours of production time was lost as a result. Furthermore, the outer edges of the fan blades were wearing, and the excessive vibration caused a failure in the motor’s white metal bearings.
“We made the production changes to increase the level of output,” said Dunbar Works’ Maintenance Manager David Pepper. “However, there were also some negative effects. Reversing the changes would have taken us right back where we started, losing valuable time and profits.”
After analyzing the balancing system specifications, Lafarge Cement chose to install LORD Corporation’s Fan Balancing System during their spring 2006 outage. As a world leader in the management of vibration, motion and noise, LORD developed a balancing system comprised of a permanently-mounted device that continuously monitors fan vibration levels and corrects for unbalance while the fan is running. The system is set up to monitor fan bearing vibration levels and the vibration phase angle in order to automatically correct for unbalanced conditions. This is done while the fan is running at operating speed, eliminating costly downtime to clean and manually balance the fan. Once levels reach a pre-set high trip point, the system switches on, commanding balance mass inside the shaft mounted system to adjust as needed to counteract the unbalance and reduce the vibration. Typical balance cycle times range from 30 to 120 seconds, depending on operating speed.
Because of the integration of LORD Corporation’s balancing system, shutdowns from excessive vibration are a thing of the past. As of September, Lafarge Cement had identified at least six scenarios when the balancing system was able to make a correction and avoid an unscheduled shutdown. The balancing system not only allows the fan to run at extremely low vibration levels but it also keeps the plant from having to deal with unscheduled stops. For Lafarge, what is equally as important as the reduction of downtime is that they are able to continue to increase their output.
“We are very happy with the results,” Pepper stated. “The average vibration level is now 1.5 mm/second, which is the lowest it has ever been. We also haven’t had to make any further adjustments to the temperature and fan speeds.”