A device for exchange and/or reaction between at least two fluids is
taught and described herein comprising at least a first space of selected
thickness and including side walls defining a first chamber provided with
a central part at least partly recessed for a first fluid flow and at
least a second chamber for a second fluid flow, the first and second
chambers being separated by a first exchanging wall adapted to ensure
exchange and/or reaction between fluids of thermal and/or mass transfer
type.