GB569390A - Improvements in or relating to tubular heat exchange elements - Google Patents

Abstract

569,390. Water-tube boilers.BABCOCK & WILCOX, Ltd. June 3, 1943, No. 8897. Convention date, June 3, 1942. [Class 64 (iii)] [Also in Group XII] Tubular heat exchange elements for example, tubes 26 constituting the walls of a boiler combustion chamber or gas pass, are formed as shown in Fig. 2 with a pair of fin-like extensions 32, a small clearance 36 being left between the extensions on adjacent tubes, and the spaces between the rear of the extensions and a backing of heat insulating material 40 being filled with a ceramic refractory material 38. Each extension comprises an outer metallic jacket 44, of low carbon steel for example, with a copper filler 46, and is formed of a number of relatively short sections fitted end to end with a small expansion space between adjacent sections, the jackets being of box-like form welded to the tube and adapted to subtend an angle of 45‹ to 60‹ around the periphery of the tube. The copper filler may be in solid form shaped to fit the jacket, or it may be molten and poured into the jacket space after the latter is attached to the tube; other materials such as lead, mercury, oil, brine, &c., or one of these liquids with copper or aluminium filings, may be used as the filler. In modifications, the rearward portion of the jacket is corrugated, and either the jacket or the tube is provided with projections to key with the filler. In another form the tube is provided with two pairs of sectionalized extensions to form a wall structure having exposed planar surfaces at opposite sides. Fig. 7 shows a construction for tubes 84 spaced in a row to provide for fluid flow therebetween, and Fig. 8 a tube 84 with a number of contiguous metallic jackets 92, each jacket having a fluid or semifluid filler 46 'and being formed as a bellows with circumferentially extending corrugations 94 welded at its ends 96 to the said tube.