Concentrated or dilutable solutions or dispersions, preparation method and uses

Heat exchanger for extracting heat from a refrigerant fluid in a motor-vehicle air-conditioning installation, comprising at least one manifold an internal volume of which is defined by at least one longitudinal bore (2) formed in an elongate solid body (1), and is in fluid communication with a row of tubes (4) which are mutually aligned in an axial direction of the at least one bore, elongate parallel to one another in a first direction substantially perpendicular to the axial direction and having an elongated cross section in a second direction substantially perpendicular to the axial direction and substantially perpendicular to the first direction, wherein only a part of the length of the cross section of the tubes projects, along the first direction, into the internal volume, the leaktightness of the fluid communication between the tubes and the internal volume being obtained by means of a cradle (10) in the form of a profiled strip, accommodating said body and brazed to it and to the periphery of the tubes, and

• wherein one end of each tube is engaged in a slot (3) formed in said body, elongate in the second direction, opening out at its two ends and the bottom of which is interrupted by the internal volume, said cradle being applied to the body in such a way as to cover over the slots and exhibiting, opposite them, elongate apertures (17) for the leaktight passage of the tubes.