GB1098080A - Heat exchangers - Google Patents

Abstract

1,098,080. Tubular heat exchangers. THERMO ELECTRON ENGINEERING CORPORATION. March 14, 1966 [March 29, 1965], No. 11003/66. Heading F4S. A heat exchanger comprises a stack of members M each of which is formed from a stepped tubular body, the narrowest end being closed by a plate 51, and has disposed at two levels around its periphery a plurality of apertures 39, 48, said members M being designed so that on stacking, two sinuous flow paths F 1 and F 2 , separated by a common heat transfer wall S, are produced. Terminal members M<SP>1</SP>, M<SP>11</SP> and M<SP>111</SP> are formed by removing a part of the basic member M, whereas areas of contact 43, 44 of adjacent members are suitably shaped and ground so that the resultant dry joint 45 is fluid tight. The heat exchange fluids may be liquid or gaseous and the elements of the heat exchanger may be made of refractory ceramic materials, e.g. silicon carbide, or from ferrous or non-ferrous metal or alloy. In the form shown in Fig. 1 combustion gases from a combustion chamber 10 supplying heat to a thermionic emitter 11 are used in the heat exchanger to pre-heat combustion air. The air is supplied through duct 55 and tubes, by virtue of apertures 39, the sinusoidal path F 1 and is thus forced to flow towards and away from the wall S. On entering, through apertures 23, the combustion chamber 10, the air is mixed with fuel, supplied by ducts 14, and the resultant hot combustion products impinge upon a plurality of thermionic emitters 11 before entering duct 13. From said duct 13 the gases enter the exchanger through apertures 58 and again are forced to flow toward and away from wall S, thus taking a similar sinusoidal path F 2 . Air entering through duct 55 is thus heated by combustion products before being used itself for combustion. The nature of the material from which members M are constructed is determined by the conditions under which the exchanger is used, with the wall S being made as thin as possible. In an alternate embodiment, shown in Fig. 4, the exchanger is made from a plurality of concentric cylinders 88, S<SP>1</SP> extending between upper and lower manifolds 110 and 96 resp. and having disposed between them members 91 which connect oppositely extending flanges 93 and 94, each of said members 91 having an aperture 92. Air for heating supplied to the lower manifold 96 takes any one of the sinusoidal flow paths F 4 , F 6 , F 8 or F 10 with hot combustion gases, supplied to the upper manifold, taking the remaining sinusoidal paths F 5 , F 7 , F 9 or F 11 , the walls through which exchange takes place being denoted S<SP>1</SP>. As above the gases are caused to flow towards and away from the wall S<SP>1</SP> by virture of the arrangement and nature of the individual members 91.