Abstract: A tube-and-plate heat exchanger comprising a plurality of plain tubes intended for a first heat carrier to pass through, which tubes are arranged in parallel rows and are received in broached holes of spaced plates. In cross section the plates are profiled so as to form, in the direction of flow of another, for example, a gaseous heat carrier, a continous symmetrically waved line, thereby forming a passage of undulatory shape for the gaseous heat carrier to flow through. Projections and depressions of each plate face corresponding projections and depressions of the other adjacent plate, thereby forming passages with alternating diverging-converging sections. The projections and the depressions of the cooled plates are made contiguous by rectilinear sections which each have an angle (.phi.) of inclination to the axis of symmetry of the cross-sectional wave line ranging from 8 to 45 deg.

Abstract: A tube-and-fin heat exchanger comprising tubes (1) for the flow of a heat carrier at some temperature, said tubes being installed in broached holes (9) provided in a stack of fins (2,3). The tubes (1) are installed so that adjacent fins (2,3) form a multiplicity of ducts for the flow of another heat carrier at a different temperature. Each fins (2,3) is provided with projections (4) and depressions (5) which form in the ducts symmetrical divergent-convergent portions for setting up turbulence in the heat carrier flow layer at the wall. The fins (2 and 3) have rectilinear portions (8) located between the divergent-convergent portions and situated opposite each other on adjacent fins (2 and 3).