GB532787A - Improvements in or relating to steam generators - Google Patents

Abstract

532,787. Water-tube steam boilers; steam super-heaters. FOSTER WHEELER, Ltd. Sept. 20, 1939, No. 26257. Convention date, Nov. 4, 1938. [Classes 123 (ii) and 123 (iii)] In a boiler having two separate furnaces 22, 23 with separate gas passes, one only of the furnaces 23 contains a radiant heat super-heater 73 which is connected in series with a convection heat super-heater 79 in the pass abolve the furnace in order that a constant degree of superheat may be maintained at all ratings by regulating the relative firing of the two furnaces. The furnaces are separated by closely spaced tubes 15, 16, 17 connected to an upper drum 18 and lower headers 19, 20, 21. The side and end walls of the furnace 22 are cooled by water tubes 57 between upper and lower headers 59, 60 and water tubes 58 between upper and lower headers 61, 62. Inclined tubes 26, 27 above the furnaces are connected to the drum 18 and to vertical headers 28, 29 which are connected by risers 30, 31 to upper drums 32, 33. The main steam and water drum 34 is connected to the drum 18 by downcomers 35. Feedwater admitted to headers 43, 44 is heated in economizer tubes 45, 46, 54, 55. Steam from the drum 34 is led into the inlet header 67 of the radiant heat superheater 68 lining the wall 13 of the furnace 23 and then flows from the outlet header 69 to an upper header 70 and through a steam line 71 to the inlet header 72 of another group of radiant heat super-heater tubes 73 lining the front wall of the furnace. The steam is then conducted to the inlet header 78 of a convection super-heater 79 in the gas pass above the furnace. The relative rates of firing of the two furnaces is controlled by a proportioning valve 84 in the discharge from the exhauster 85 of the mill 83 which is fed with pulverized fuel.