Eclipse Inc., is a worldwide manufacturer of products and systems for industrial heating and drying applications. The company designs and manufactures a wide variety of gas and oil burners, recuperators and heat exchangers, complete combustion systems, and accessories for combustion systems. Eclipse Extern-a-Therm recuperators are tubular air-to-air heat exchangers designed to recover waste heat from industrial exhaust gases. The heat recovered is used to preheat combustion air for the system's burners, which increases fuel efficiency. The Extern-a-Therm burner is arranged for fixed air with a bypass pilot to give maximum adjustment of low-fire/ignition gas flow realizing that the system will be fuel lean at cold start, becoming less lean as the system comes up to temperature. Customers have measured pre-heated air temperatures of 700°F. This indicates a fuel savings of 20%. Which means an Extern-a-Therm recuperator can pay for itself in less than two years, based on the amount a fuel cost of dollar 7.00 per 1,000 cubic feet of natural gas.