GB1295757A - - Google Patents

Abstract

1295757 Tube walls for furnaces BABCOCK & WILCOX CO 6 May 1970 [7 May 1969] 21835/70 Heading F4B A tube wall comprises panels of circular tubes separated by a zone between 102 and 102A in which lie extensions of each tube. The extensions of some of the tubes 37A in the lower panel and some of the tubes 37C in the upper panel curve in the zone to project from the wall for connection to outlet or inlet headers 49, 57 respectively. The curved extensions are arranged in pairs, one from each panel, to lie side-by-side in the zone, Fig. 6, and the curved extensions are oval in cross-section with the major diameter in the plane of the curve, Fig. 8, so that the tubes 37B, 37A or 37B, 37C in each panel are evenly spaced, while the spacing of the extensions in the zone is uniform but less than that. of the tubes in the panels. Webs 103, 105 close the inter tube spaces in the lower and upper panels respectively, and fillets 106, and filler webs 107 close the spaces in the zone. As shown in Fig. 4, the bottom panel comprises tubes 37A forming part of a first fluid pass and tubes 37B forming part of a second fluid pass, the panel above comprises tubes 37B each forming a continuous flow path with a corresponding tube in the bottom panel and forming part of the second fluid pass, and tubes 37C forming part of a third fluid pass. A top panel, separated from the intermediate panel by a zone 101A, 101, comprises tubes 37C and 37C<SP>1</SP> forming a third fluid pass. The extensions of the tube 37A in zone 102A, 102 are connected to an outlet mixing header 49 which is connected to the inlet header for the second pass tubes 37B, while the extensions of the second pass tubes 37B in zone 101A, 101 are connected to a mixing header 53 feeding a third pass inlet header 57 to which are connected the extensions of tubes 37C in zone 102A, 102 and the extensions of tubes 37C<SP>1</SP> in zone 101A, 101. In a modification having only two fluid passes, the top and bottom panels comprise only tubes of the second and first passes respectively, the intermediate panel including tubes of both fluid passes.