GB1163301A - Improvements in or relating to Supporting Tubular Walls of a Vapour Generator - Google Patents

Abstract

1,163,301. Once-through vapour-generators; tube walls. BABCOCK & WILCOX Ltd. 26 Aug., 1966 [27 Aug., 1965], No. 37040/65. Headings F4A and F4B. A once-through forced-flow vapour generator includes a furnace chamber into which front and rear wall burners 3 fire, and from which an upright gas pass 2 extends, leading into a lateral gas pass 7 containing reheater tubes 7a, and a downpass 9 containing economizer tubes 9a. The gas pass 2 up to the level of the lateral pass 7, is lined by parallel finned tubes 21, gas tightly welded together to form a membrane wall. At the level of lateral pass 7 in the front and side walls, the inclined tubes 21 each connect to a vertical tube which are welded side by side in groups 10, and which discharge into upper headers 14. The headers 14 discharge through conduits 14a to a central collector (not shown) which feeds a second pass of larger diameter vertical wall tubes 11 disposed in groups between the groups 10. Vertical external support straps 12 extending parallel to the vertical tube groups 10, support the front and side walls from spring mountings 13, some of which through beams 16 further support U-shaped superheater tube platens 15. In the rear wall the inclined tubes 21 connect to upright tubes which in turn discharge into headers 33. The vertical support straps 12 are attached to the inclined tubular walls 21 at differing levels P, Q. To attach the straps to the walls, blocks 31 with rear surfaces contoured to the tubes 21, are welded thereto, and the enlarged heads 12a of the straps 12 are held in abutment against these blocks by overlapping lugs 33 welded to the blocks. Alternatively (Fig. 4, not shown), a block having tubular conduits through it may be incorporated flush within the tubular wall, the enlarged strap head engaging against the lower edge of the block and the strap extending up along a recess in the outer surface of the block. Lugs welded to the block then overlie the strap.