Process for producing a material and heat exchange device

Process for producing a heat and material exchange device having a stack of fixed ventilators to promote gas mixing, each ventilator being constituted by four deflectors whose mean normals are inclined and substantially generated one after another by rotation about vertical axes, the sum of the four angles of rotation being 360° and the ventilators being stacked in successive horizontal layers amidst which each deflector forms a part of two adjacent ventilators turned in opposite directions and such that there is sufficient space between two adjacent deflectors for the passage of gas, wherein the deflectors of the ventilators are neither rhombi of which a diagonal is horizontal nor triangles of which the base is horizontal or

• the angles of rotation of the deflectors are not 90° or
• the axes of rotation do not pass through the ends of the horizontal diagonals of the deflectors in the form of rhombi or
• the axes of rotation do not pass through the ends of the horizontal bases of deflectors of triangle shape or
• the upper summits of the rhombi or of the triangles of a layer do not coincide with a summit of a rhombus or a triangle of the immediately superjacent layer, the process comprising:
• cutting out planar sheets of material so as to obtain cut sheets;
• and
• folding the cut sheets to form a structure of accordion sheets having planar surfaces forming the deflectors.