Rugged, reliable rotary valves seal the deal - FLCase: aC Power in Colver, Pennsylvania a coal-fired power plant solves a feeding problem by installing ceramic-lined rotary valves in a line injection.rotary feeder line,Ceramic Rotary Valve - FLCeramic Rotary Valve. Exceptional abrasion . Raw Line. •. Lignite. •. Cement . Application: Rotary feeder metering to a screw pump conveying fly ash at.