Abstract: A heat exchanger, includes modules defining a first path for a first fluid, each having two metal sheets forming between them a network of channels which are located in parallel with each other from the fluidic point of view, each channel interposed between two neighbouring channels of the network being, over the whole of its developed length, adjacent to these two neighbouring channels from which it is isolated by two respective weld lines connecting the two metal sheets; a second path for a second fluid is defined between the modules; and an overall variation in the passage cross-section over the length of at least one of the paths with continuity of profiles of the channels.

Abstract: The invention relates to a plate heat exchanger (1) of the type comprising an impervious chamber (2), a bundle of plates (3) arranged in said chamber (2) and providing therewith a free space (4), an inlet pipe (10) for hot fluid in a first circuit of this bundle (3), an outlet pipe (12) for the cooled fluid, an inlet pipe (20) for a cold fluid communicating with the inlet of the second circuit of this bundle (3), and an outlet pipe (21) for the heated fluid. The heat exchanger also comprises means (25) for channelling the cold fluid along the internal wall of the chamber (2).