Cement Dust and Vibration at Cement Plants
Replacing the bearings with Rexnord® 6000 SHURLOK(TM) adapter mount roller solved the problems that were causing bearing failure and simplified installation as well.
The fan is driven by a 150 HP motor through Gates Polychain and runs at 2000 to 2500 RPM. The pitch diameter of the fan blade is 54", with its 2-15/16" straight shaft supported on 20" bearing centers. The previous bearings were failing in three months or less because of several conditions. Vibration inherent in the application caused the bearing's lock nut to back off, and the loose mounting caused premature failure, even though the customer monitored the vibration weekly. Problems stemming from the installation also were an issue. First, it was difficult to install the previous bearings' split housings correctly because of tight spacing where the field tolerances had to be set. This led to running conditions that were often either too tight or too loose, resulting in shorter bearing life. Second, fine cement particles found throughout the operation would end up in the bearing during assembly and installation. This decreased the life of the lubricant and further shortened bearing life.
New Bearings Meet the Challenges
The customer selected Rexnord KAF6215 SHURLOK adapter mount roller bearings for the application because they incorporate features that eliminate many of the problems associated with the fan application. Their single-housed design with factory-preset clearances and lubrication made on-site adjustment unnecessary and avoided exposing the lubricant to cement dust. The bearings also incorporate an innovative tapered sleeve design that provides up to 25% greater shaft grip in the plant's vibratory application.
The new bearings also incorporate Spyglass(TM) Optical Strain Sensors (OSS), which provides instant feedback during installation to achieve optimal shaft grip.