| 摘要 |
1289972 Tubular heat exchangers BABCOCK & WILCOX Ltd 11 Dec 1969 [11 Dec 1968] 60583/69 Heading F4S In a heat exchanger serving as an air heater wherein a plurality of tubes 2 extend from a tube plate 1 into a passage for fine gases, the side of the tube plate remote from the passage is provided with a layer of material of thermal conductivity less than that of the tube plate. As shown, the layer comprises concrete cladding 7 with a rendered surface 8; alternatively it may comprise stagnant air maintained in position by a screen. The tubes 2, which may be glass or metallic with an inert coating, extend through circular apertures 3 and concentric stub pipes 4 and are secured in position by annular fibreglass seals 5. An inert coating 9 covers the inwardly facing tube plate surface. In operation, flue gases flow across the tubes in direction A and air to be heated flows through the tubes in direction B. The insulation arrangement of the invention serves to inhibit transfer of heat from the tube plate to the air and so ensures that the temperature of the tube plate remains above the dew point of the flue gases. |
