Founded in 1989, Air Heater Seal is one of the leading manufacturers of a patented, flexible sealing system for rotating regenerative air preheaters. The company manufactures various types of dampers, fabric expansion joints and flexible full contact seal systems, expansion joints, structural steel and dutch work. Its wide variety of dampers includes louver, butterfly, guillotine with opposed and parallel blades, and single and biparting blades. It also offers various structural steel products, such as rails, ladders, platforms, and single items and accessories. The company has a field service group that provides complete air heater inspection and leakage testing. Air Heater Seal also provides installation and supervision of air heater seal package and other products it manufactures. Headquartered in Waterfood, Ohio, the company holds a patent on sealing system in the United States, Canada and India.