Metallized Carbon Corporation (Metcar) has designed a range of bearings designed for louver dampers in boiler applications for instance, in coal- or refuse-fired power plants.
The Metcar bearings are suitable for boiler damper blade shaft bearing applications because of their ability to cope with extremely high temperatures. At these high temperatures, oil/grease lubricated bearings are problematic because the lubricants can melt, volatilize or carbonize, causing bearings to gaul and seize, therefore rendering the dampers useless. They are also suitable for other damper applications, such as in dampers that provide fresh in air underground transportation systems, given that the restricted access to these dampers makes routine maintenance on oil/grease lubricated bearings too difficult. Metcar self-lubricating carbon-graphite bushings are also used as stem bearings on high temperature butterfly valves, high temperature ball valves and high temperature wafer style dampers.
Standard pillow blocks and flange blocks with Metcar bearing inserts are available with cast iron, stamped steel, or stamped stainless steel housings. Standard flange block bearings are available in English and metric sizes for shafts up to 5 inches (127mm) in diameter and standard pillow blocks will accommodate shafts to 3 inches (75mm) in diameter.