| 摘要 |
758,030. Tubular heat exchangers; heat insulation. ESSO RESEARCH & ENGINEERING CO., [formerly STANDARD OIL DEVELOPMENT CO.]. Feb. 3, 1954 [Feb. 20, 1953], No. 3259/54. Classes 64(2) and 64(3). In a tubular heat exchanger comprising a bundle of parallel tubes extending between tube plates 3, 4 and surrounded by a shell 1, the external fluid passing through the shell and over the tubes is withdrawn from the shell by way of a space between the shell wall and a baffle 10 disposed within the shell thereby maintaining the shell at substantially the same temperature as the tubes so that thermal stresses are minimised. Fig. 1 shows one arrangement in which the space between the baffle and the shell wall is annular and is closed at one end by a flange 11. Baffles 17 and spiral baffles or perforated grids or discs 18 are provided to promote heat exchange. The external fluid outlet 8 from the annular space is located at the same end of the shell as is the external fluid inlet 7 to the shell. In order that the tube assembly may be withdrawn, the tube plate 4 is small enough to pass through the baffle 10 which is fixed to the shell wall. Alternatively the baffle may extend to the tube plate 4 in which case the inlet pipe 7 extends through the annular space to the space within the baffle 10. The casing may be heat insulated by a layer of calcium silicate or mineral wool and the baffle 10 may likewise have a layer of thermal insulation on its inner surface. The tubes and tube plates may be made from a steel alloy containing chromium and molybdenum and the inlet header 5 may have a thin chromium liner. The apparatus is said to be of use particularly when the heat exchanging fluids are at high temperatures and pressures such as in a fluid hydroforming reactor. |
