Patent ID: 6929470

Claim:
A heater for heating a gaseous stream flowing in a downstream direction through a duct, the heater comprising: a heating gas supply pipe extending at least partially across the duct, the heating gas supply pipe including a plurality of spaced-apart gas pipe outlets to discharge a portion of a heating gas into the duct generally in the downstream direction; a flame shield extending from a location at or near the heating gas supply pipe at least partially across the duct; a plurality of gas supply spuds disposed upstream of the flame shield, the gas supply spuds including a plurality of gas spud outlets to discharge another portion of the heating gas into the duct; a plurality of jet pumps each extending from a jet pump inlet at an upstream location upstream of the flame shield to a jet pump outlet at a downstream location downstream of the flame shield, each jet pump inlet being disposed near one of the gas spud outlets to receive the heating gas from the gas spud outlet and being spaced by a distance from the one of the gas spud outlets to receive the duct gas from the gaseous stream for premixing of the heating gas and the duct gas in the jet pump.