Rotating process machinery depends on bearings, either rolling element bearings or fluid film bearings. These parts counteract gravity to keep the shafts moving as freely as possible without wear or excessive maintenance. The characteristics of each type of bearing leads to the maintenance, life span, and type of load possible for the application.
Babbitt is a widespread material for bearings. It allows for smooth start-up and shut-down while offering conform-ability and embed-ability reducing damage to the spinning shaft. Babbitt bearings must be limited to a maximum temperature of 130°C or warping may lead to misalignment. Bronze can be a substitute for Babbitt bearings for higher temperature applications but can be damaged more easily by contaminants.
Fluid film bearings depend heavily upon their design, and application specific designs can be highly specific. An operating pressure must be developed in the fluid to counteract gravity. Bearing clearance, the difference between the bearing bore and shaft diameter, greatly affects dynamic performance from temperature changes and power loss. Even the manner in which lubrication is introduced into the bearing can drastically change the performance. A flooded bearing will have higher power losses and operating temperatures than a directed lubrication bearings.
Click here for the full article from Processing Magazine.