Performance of Rolling Element Bearings in Steam Heated Drying Cylinders, 1997 Engineering Conference Proceedings

An elevated rolling element bearing operating temperature, whether generated by the internal bearing components or increased by external sources, normally results in decreased bearing service life. The latter condition contains special significance when considering the effects on bearing performance in applications involving the harsh operating environment of drying cylinders and Yankee dryers. Of obvious and extreme importance is the overall effect on bearing performance due to the heat radiated to the bearing from the passage of steam through the dryer journal. Alleviating the large amount of heat supplied by this single application condition has been a goal of every builder of paper machine drying cylinders and Yankee dryers. Providing bearings as well as detailing proper recommendations to operate bearings in this severe environment has always been a goal of rolling element bearing manufacturers. This presentation will focus on the thermal parameters of drying cylinders/Yankee dryers that influence the performance of rolling element bearings. This will be accomplished through an analytical approach outlining the theoretical relationships between steam temperature, journal insulation, lubricant viscosity, circulating oil system flow rate and bearing operating temperature.