Abstract: The module is formed from two sheets welded to each other by laser welding. Longitudinal weld beads define between them longitudinal ducts for the flow of a first fluid. The sheets are also joined together by a peripheral weld bead. The weld bead defines, beyond the longitudinal ducts, a transition zone which narrows from the longitudinal ducts up to the gap. Weld spots are previously formed in this zone. Once the welds are completed, the module is formed by the injection of a fluid under pressure through a gap in the weld bead. Utilization for rendering mutually compatible the variations in width of the module during hydroforming in the end regions and for forming, with the transitions zone, a flow distributer to the various channels during operation.

Abstract: A device including a side wall (3) and bottom walls (4, 5) together forming a metal vessel (2) containing a core (7) for exchanging heat between two fluids, i.e. preferably counter-flowing heating and heated fluids. The core is arranged vertically within the chamber and radiates heat towards the inner surface of the side wall through an intermediate space (24) provided between said wall and the core and filled with a fluid which is the same as or different from one of the fluids flowing therethrough. The chamber is cooled both by exposing the side wall (3) to the atmosphere and by using a thermosiphon effect to cause the fluid in the intermediate space (24) to flow through a closed circuit (30) including said intermediate space and at least one pipe (31) located outside the chamber and connected thereto at two vertically spaced points. The device may be used in oil industry exchangers.