| 摘要 |
A vented heat transfer tube assembly comprising a pair of fluid circulation tubes disposed co-axially one within the other, the inner tube being double-walled and held substantially concentric within the outer tube by a plurality of pairs of diametrally opposed depressions or dimples formed in the peripheral surface of the outer tube at regular intervals. Each depression or dimple projects inwardly such as to engage and indent the peripheral surface of the inner tube and to cause a corresponding portion of the inner tube to bulge inwardly during forming of the dimples in the periphery of the outer tube. The double-walled inner tube is thus coaxially supported within and assembled to the outer tube by the dimples, and a fluid may be circulated through the inner tube while another fluid is circulated in the annular space between the peripheral surface of the inner tube and the inner surface of the outer tube with the result that, when the fluids are at different temperatures, heat may be transferred from one fluid to the other through the double wall of the inner tube. The double-walled inner tube is made of coaxially disposed tubes or conduits, at least one of which is provided with longitudinal bulges forming fluted passageways or channels vented to the ambient, such that accidental leakage of fluid circulating in the inner tube, or of fluid circulating between the inner tube and the outer tube, is vented to the ambient, rather than causing intermixing of fluids. The venting passageways or channels may be filled with a chemically inert good heat conductive material, preferably in the form of a gel, and the two coaxially disposed tubes are in tight surface contact with each other between the fluted passageways or channels.
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