FLAME-TUBE BOILER Russian patent published in 2003 - IPC

FIELD: thermal engineering; water heating. SUBSTANCE: flame-tube boiler has cylindrical shell with front and rear tube sheets; flame tube disposed in its water space; two-pass fire-tube bundle formed by first-pass fire-tube bundle whose inlet ends are secured in rear tube sheet holes and outlet ones, in front one, as well as by second-pass fire-tube bundle whose inlet ends are secured in front tube sheet holes; rear swivel chamber between flame tube and fire-tube bundle whose front wall is made in the form of tube sheet rigidly fixed to the latter; cooling chamber disposed between rear swivel chamber and gas duct in water space with fire-tube ends of second bundle passed through this chamber and through holes in rear tube sheet wherefrom they enter gas duct. Assembly including rear swivel chamber, cooling chamber, and gas duct has split in whose plane second-pass fire tubes have taper joint. Cooling chamber is provided with water discharge tube communicating with water space of boiler and with circulating inlet feedwater branch pipe; cooling chamber wall opposing flame tube is shielded by refractory wall. EFFECT: enhanced efficiency of burnt fuel heat utilization; enhanced reliability and repairability. 3 dwg