PURPOSE: To mix a fluid favorably in a pipe and enhance a heat transfer rate greatly by projecting reinforcing pieces on a grooved inside surface in a discontinuous manner, in a flat heat transfer pipe suitable for a laminate-type heat exchanger.
CONSTITUTION: A plurality of minute parallel grooves 13 are cut in one side of a flat plate 10 of a highly heat-conductive metal, and projections 12a, 12b constituting the reinforcing pieces 12 are provided thereon. Then, the flat plate 10 is folded along a fold line 20, the projections 12a, 12b on both sides are abutted against each other and a joint edge parts 10a, 10b are jointed to each other to produce the flat heat transfer pipe 11. In this case, the fluid passed through the interior of the pipe 11 is mixed favorably by the presence of the projections 12a, 12b constituting the reinforcing pieces 20. In addition, by the plurality of grooves 13 cut in the inside surface of the pipe 11, the effective area for heat transfer is increased and the heat transfer rate is greatly enhanced.
CHIAKI TAKAO
ARAI TOORU
MINAGAWA SADATOSHI
AIBA KAZUMI
TAKEDA SUMIYOSHI
