GB881925A - Improvements in tubulous boilers - Google Patents

Abstract

881,925. Forced-flow steam boilers. BABCOCK & WILCOX Ltd. Aug. 26, 1960 [Sept. 5, 1959], No. 29476/60. Class 123(2) In a forced-flow, once-through, tubulous boiler of the kind having walls lined by sections of horizontal tubes and connecting tube lengths joining the sections at different levels so that each tube circuit includes a similar number of tube bends and gaps in the wall lining, other than for burners, &c., are minimized, the connecting tube lengths between adjacent sections are arranged to overlap. As shown in Fig. 1, tube sections 1A, 2A are joined respectively to sections 1B, 2B by overlapping semi-circular bent portions 1C, 2C the tubes of which are spaced by an amount equal to the horizontal tube spacing and which have a common centre 3 located between the upper and lower sections. In an alternative arrangement, Fig. 2, the tube lengths of sections 5, 6 are connected to respective sections 7, 8 by bent portions 9, 11 of different radii so that the spacing of the tubes throughout the circuit is uniform and some of the bent portions overlap. In an arrangement, Fig. 4, where the connecting tubes are bent at the same radius the bends preferably extend through an angle, e.g. of 45 degrees, adjacent sections 1A, 2A being joined with superadjacent sections 1B, 2B by groups of upwardly inclined tubes 1C, 2C, the latter being bent rearwardly behind the former. A boiler is described where the transpositions, from one tube section to another, are located in vertical alignment intermediate the side walls of the furnace.