GB726244A - Improvements in tubulous vapour generating and vapour heating units and the operation thereof - Google Patents

Abstract

726,244. Water-tube steam boilers; steam superheaters. BABCOCK & WILCOX, Ltd. March 27, 1953 [March 27, 1952], No. 8522/53. Classes 123 (2) and 123 (3). A steam boiler is fired by two rows of cyclone furnaces A and B each arranged as described in Specification 552,747, [Group XII], and operating at temperatures above the ash-slagging temperature of the fuel, the furnace gas passing into a common secondary furnace 10 and then through slag screens 94 and 96 into a steam generating tube lined radiation chamber 12 in the upper part of which is disposed a pendant, radiant superheater 14, 16 constructed for example as described in Specification 720,833. The gases leave chamber 12 through an outlet 18 and flow downwardly through a pass 22 which is divided by vertical partitions into three separate passes, the outer of which locate convection superheaters such as 24 whilst the middle pass locates a convection reheater, the gases passing to an air heater 32 through a breeching 28. The cyclone furnaces and furnace chamber 10 are lined with generating-tubes which, together with those of chamber 12, extend between a steam-and-water drum 46 and a water drum 44, To temper the furnace gases entering the radiant superheater and so to prevent deposition of slag therein, cool flue gases are admixed with the furnace gases near the superheater inlet whilst to control the temperature of superheat, a further quantity of flue gas is introduced into the secondary furnace. The flue gas is withdrawn from breeching 28 at 34 by a fan 158, the tempering gas being passed through a damper-controlled duct to a chamber 38 whence it flows into chamber 12 through ports controlled by adjustable louvres whilst the superheat-control gas is passed to a chamber 42 whence it flows downwardly into furnace 10. Specification 675,410 also is referred to.