Original industrial trade vintage catalog for AIR PREHEATER CORPORATION. Main office was located at 40 East 34th Street, New York City, NY. Manufacturers of the Ljungstrom Air Preheater for heat recovery from flue gas, preheating combustion air, improving boiler efficiency, increasing streaming capacity, fuel and money savings in public utility and industrial steam power plants and industrial furnaces. Disbound from a large 1931 industrial catalog, this unique old two page technical brochure would display wonderfully matted and framed. A marvelous addition to your retro industrial equipment library. Slight damp stain on outer edge.