| 摘要 |
985,464. Tube-type heat exchangers. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Oct. 17, 1963 [Oct. 17, 1962], No. 41045/63. Divided out of 985,463. Heading F4S. A heat exchange system includes a number of tube units each with inlet and outlet headers 22, 23 for one fluid (the secondary fluid) flowing through tubes 50 (shown as U-tubes), and a surrounding shell 48 having an inlet port 51 for another fluid (the primary fluid) flowing over the tubes. In the unit shown the primary fluid passes out of the shell through ports 52. In the arrangement according to the invention all the units project downwardly from the floor of a main header 41 (Fig. 1, not shown) common to all the units, with the ports 51 opening into the header space and with each shell 48 extending out of the header through a corresponding aperture in the header floor and being sealed around said aperture. Each sealing means shown comprises a ring member 53 joined to the shell by a flexible bellows 54 so as to be movable longitudinally of the shell. Linkage 55 including a rocker arm 56 is actuable by a screw and nut adjustment 57 (Fig. 4) operable from outside the heat exchanger unit to move the ring 53 into sealing engagement with the header floor. The unit shown is of rectangular cross-section (Fig. 3, not shown) and the primary fluid flow is in two passes separated by a baffle 49. The primary and secondary fluids flow in contraflow in each pass. In a modification described (Figs. 5, 6, not shown) the unit is cylindrical, the U-tubes being arranged in an annular bank each with one limb in a first pass for the hottest primary fluid and defined by a tubular baffle, and another limb in the second pass formed by the annular space around the baffle. In this construction the primary fluid inlet port 51 is connected to the interior of the baffle by a short duct 59 (Fig. 6, not shown). In a further alternative a once-through flow path may be provided for the primary fluid by a shell of U-shape with one limb shorter than the other. The heat exchanger system described is associated with a nuclear reactor in which the primary coolant is a liquid metal flowing in a cycle through the reactor and heat exchanger units, the circuit including a reservoir in which the lower ends of the units are immersed. Hot liquid from the reactor passes into the main header and thence through the units 21, inlet ports 51. The heated secondary coolant from the units 21 passes in known manner to other heat exchangers (not shown) for generating steam.
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