RECIRCULATION U-SHAPED RADIATION PIPE Russian patent published in 2004 - IPC

FIELD: devices of indirect heating of heat-treating furnaces filled with special protective atmosphere. SUBSTANCE: the recirculation U-shaped radiation pipe has a U-shaped radiating body with an offtake branch pipe, recuperator in one branch and a burner in the second branch formed by a system of coaxial pipes, and the air for burning in the burner after the transfer between both branches is divided into the primary and secondary ones in the circular channels formed with the aid of the coaxial pipes providing for a double-stage burning of gas, and is provided with a pipe with holes at the end for supply of gas to the peripheral circular channel, the middle circular channel is provided with holes for passage of the primary air, and distribution of the summary air into the primary and secondary ones is accomplished with the aid of an adjusting nozzle at the end of the central pipe, the offtake branch pipe is connected to the middle circular channel in the burner through a special recirculation by-pass. An adjusting device is installed on the special recirculation by-pass. EFFECT: reduced temperature condition by-pass, burner zone and reduced output of NO_x in the process of burning. 2 cl, 1 dwg