Industrial furnace applications come in various types and sizes; however, all place similar demands on the bearings they use.
Due to the high temperatures within a furnace application, the shafts that extend through the furnace will grow significantly in length. This heat will also travel down the shaft to the bearings, subjecting them to higher-than-normal operating temperatures. In addition, maintaining proper atmosphere within the furnace is critical to effective operation.
For bearings to survive in these temperatures while ensuring proper operation of the furnace, specific characteristics must be designed into the bearing.
Most standard bearings have a maximum operating temperature of 225°F, but a furnace bearing often must endure temperatures up to 400°F. Rex and Link-Belt bearings have been developed to withstand these temperatures.
Increased internal bearing clearance in the Rex and Link-Belt lines allows for thermal expansion of steel components, and special, high-temperature greases are applied to the bearings. Steel rolling element retainers are used, as well as high-temperature seal materials.
To accommodate significant shaft growth typical in this type of application, Rex and Link-Belt expansion bearings are equipped with dog-point set screws or special pins inverted in the bore of the bearing. These devices ride in a slot which has been machined into the shaft to allow expansion without allowing the bearing to turn inside the bore.
In addition, we’ve designed Rex and Link-Belt bearings with special features to prevent internal furnace gases from escaping at the point where the shaft exits the furnace. Typically, the expansion bearings will have an extended end closure to seal the bearing and shaft while allowing for shaft growth. The fixed bearings feature specially designed locking collars that seal around the shaft.
Examples of typical expansion and fixed bearings are shown below.
When the temperature rises, you need bearings that can stand the heat. If you have questions or would like to talk to one of our application engineers about our Rex and Link-Belt Series for your high-temperature application, call (317)273-5781 or email [email protected]. For videos and other demos, visit our YouTube channel.
Dale Stallard
Dale Stallard started with Rexnord in 1988 and has held different positions in Quality Control and Product Design and Development at multiple facilities. Dale is a Senior Application Engineer supporting Rexnord's bearing business. In his current role, he provides customers with support such as helping them select the proper bearing, onsite assistance, maintenance and installation training, and troubleshooting with any issues.