GB616011A - Improvements in steam generating and superheating units - Google Patents

Abstract

616,011. Water-tube steam boilers. BABCOCK & WILCOX, Ltd. Aug. 19, 1946, No. 24599. Convention date, Aug. 25, 1945. [Class 123(ii)] In a steam boiler comprising horizontally disposed upper and lower drums 28, 29, Figs. 1 and 2, connected by a bank of upright steam generating tubes 31 located together with a superheater 41 in a space 18 laterally adjoining a combustion chamber 17, as described for example in Specification 433,834, a combustion gas by-pass 48 is provided between the superheater and the upper drum and is adapted to be closed to a selected degree by a baffle 47 supported by some of the said tubes 31. As shown, the space 18 is divided by transverse baffles 23, 24 to provide seriallyconnected passes 25, 26, 27, and in the first or rear pass 25 the tubes 31 are in two groups 37, 38 defining a superheater space therebetween, the two inner rows 38c of tube group 38 being bent forwardly and upwardly in a reverse curve above the upper end of the superheater to be jointed with the drum 28 adjacent the tubes of the group 37 and to encircle the baffle 47. The latter is preferably formed of one or more horizontal rows of readily removable tiles, each tile having a length equal to twice the tube pitch of the rows 38c with adjacent tiles making joint at a tube and the lowest row of tiles abutting against bracket or stop members 49, clamps, etc. individually welded or otherwise secured to successive tubes in the inner row 38c. The superheater is supported in known manner by means interposed between the headers 42, 43 thereof and the lower drum 29, and the said headers are protected by a baffle 46 which extends from the drum 29 and defines the lower boundary of the passage available for gas flow over the superheater. A modified construction is shown in Fig. 4.