GB651043A - Improvements in steam generators - Google Patents

Abstract

651,043. Water-tube steam boilers; superheaters. BABCOCK & WILCOX, Ltd. Aug. 6, 1948, No. 20779. Convention date, Aug. 8, 1947. [Class 123(ii)] In a steam boiler comprising a furnace 6 and secondary combustion chamber 14 from which combustion gases flow laterally through a bank 30 of steam-generating tubes, depending from an upper steam-andwater drum 22 to a lower water drum 20, and a chamber 39 to a vertical pass 32, primary and secondary superheaters 58, 80 in the form of rows of multiple-loop tubes are disposed in the pass 32 with some of the tube lengths 62, 64, 66, 68 and 82, 84, 86, 88, respectively, thereof extending upwardly in the space between the tube bank 30 and a baffle 60 between said chamber 14 and pass 32. Preferably the upwardly extending superheater tube lengths are more widely-spaced transversely of the gas flow than the horizontal lengths. The two superheaters have inlet and outlet headers 52, 70 and 78, 90 and are associated with an intermediate attemperator which is disposed within the drum 20 and is coupled to the headers 70, 78 through conduits 72, 76. An economizer 34 is also located at the end of the pass 32 from which the gases pass in succession through a primary air heater 37, a low temperature economizer 36, a secondary air heater 38, a duct 40 and a further air heater 42 to a flue 44. The economizer 34 is formed of two similar side-by-side horizontally-extending tube coils which are supported from upper side and intermediate outlet headers 100 by tubes 92 lining the side walls of and subdividing the pass 32, and feedwater is supplied to the inlet headers 114 thereof through tubes 112 leading from the primary economizer 36. The secondary combustion chamber 14, also a primary cyclone chamber 10 and intermediate furnace chamber 12, may be lined with steam-generating tubes extending between the drums 20, 22 and lower headers such as 26-29. Similarly the pass 32 is lined vith steam-generating tubes, in addition to the tubes 92, namely, tubes 144 defining the baffle 60, the upper ends 140, 142 of these tubes being displaced to provide a flow passage for combustion gases, and steam tubes 54 leading from the drum 22 to the primary superheater header 52.