GB891024A - Improvements relating to a steam generator installation - Google Patents

Abstract

891,024. Water-tube steam boilers; superheaters. THOMPSON WATER TUBE BOILERS Ltd., JOHN. March 10, 1958 [March 11, 1957], No. 7984/57. Classes 123(2) and 123(3) A forced circulation steam boiler has three separate furnaces 3 . . . . 5 for evaporation, reheating and superheating respectively contained in a tube-lined casing 1 and separated by gastight walls 6, 7 of steam generating tubes, each furnace being individually fired by pulverized fuel burners 16. In vertical section each furnace is arranged as in Fig. 3 which shows the evaporating furnace. The outer walls of this furnace are lined with steam generating tubes 8 . . . . 10, and it contains in its upper portion radiantly-heated platens 17 of generating tubes. The furnace has a top outlet into a lateral pass leading into a downpass, the passes locating secondary and primary superheaters 18, 19 and an economizer 20. The reheating furnace 4 has outer walls 11, 12 lined in part with reheater tubes R and in part with evaporating tubes E and contains platens of reheater tubes arranged and disposed as for the platens 17. The outlet passes from this furnace contain secondary and primary reheaters and an economizer. The super-heating furnace 5 has outer walls 13 . . . . 15 lined in part with superheater tubes 5 and in part with evaporating tubes E and contains platens of superheater tubes arranged and disposed as for the platens 17. The outlet passes from this furnace contain secondary and primary superheaters and an economizer. In a modification the furnace units are physically separated from one another. During starting overheating of the steam heating tubes is prevented by delaying the firing of furnaces 4, 5 until sufficient steam is being generated in furnace 3 to cool the steam tubes adequately. During operation the firing of the furnaces4, 5 is independently adjusted to maintain constant steam temperatures over a wide load range.