GB877116A - Improvements in tubulous boilers - Google Patents

Abstract

877,116. Tube walls for furnaces. BABCOCK & WILCOX Ltd. April 29, 1960 [May 1, 1959], No. 15044/59. Class 51 (1). Horizontal tubes lining the walls of a boiler furnace are connected in parallel and arranged so that each of the parallel circuits receives approximately the same heat input and are supported by vertical members which are heated during operation to reduce differential vertical expansion. Wall tubes 23 connected in pairs to rods 25, Figs. 4, 5 are supported from slots 21 in vertical members 20 within the furnace insulation 47. The members 20 are supported by lugs 30 from vertical stays 28, which are supported from horizontal back-stays 43 so as to allow for differential horizontal expansion. The furnace wall is sealed by plates 39, strips 41, 42 sealing the horizontal gaps between plates 39 and the gaps between the plates 39 and supports 20 respectively, while allowing expansion. The support members 20 may be replaced by angle members 52, 53 welded to vertical tubes 51 connected in the boiler circulation, Figs. 7, 8. The furnace wall is divided into zones, each zone receiving a different heat input, and the tubes of each zone are divided into groups. The tube groups comprise pairs of tubes, each tube pair having adjacent inlet and outlet ends, and the tubes of a pair extending in opposite directions round the furnace walls. The adjacent inlet ends of pair of tubes are connected to tubes 68 leading from a lower zone and adjacent outlet ends of another pair of tubes of the same group are connected to tubes 67 leading to corresponding tubes in an upper zone by bores 70 in a block 69, Figs. 11 and 13, and the tubes 67 form part of the suspension of the tube walls, Fig. 12. The tubes of a group may be crashed sidewardly near their inlet and outlet ends, so that a plate 81, Fig. 16, may be welded between the tubes 84 leading to the upper zones and the tubes 83 leading to the lower zones so that the upright tubes may support the horizontal wall tubes. The furnace may have a lower part lined with vertical tube lengths, and horizontal tube lengths lining the upper region of the furnace may be connected in series by upright tube lengths lining the side walls of a lateral gas pass. The firing zone or the region of the burner ports in the firing zone may be lined with upright tubes.