| 摘要 |
A heat exchanger having an outer shell member and having a helically wound volute member which is double walled and includes a finned outer tube and a close-fitting inner tube, and the heat exchanger further including a core member which extends through the helical volute member and closes its central aperture to confine the flow of liquid in the outer shell member to flow through the fins, rather than pass through the aperture through the center of the helical volute member. The fins on the double walled volute member are wound as close to touching the core member as possible and the diameter of the core member and of the outer shell member is such that the fins closely fit the space between them. Both the finned tube and the inner tube pass completely through the shell member, and the finned outer tube is soldered to the shell so that any leakage between the tubes will pass outside the heat exchanger shell member rather than mixing the heat exchanger liquids. Since the volute member cannot in practice be closely fitted both to the outer shell member and to the core member due to manufacturing tolerances, a process is provided by which two helical wires are wound, one against the core member and one against the shell member, and both helical wires have the same pitch as the volute member and are maintained in close proximity respectively to the core member and to the shell member, and are longitudinally spaced approximately midway between convolutions of the volute member.
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