Abstract: Double-flow dehydration tunnel characterized in that it comprises, above an intermediate space (5), a collecting and channelling means (20) arranged to collect separately the current of hot air (10) coming from the recycling duct (7) containing the heater (9) and the current of less hot air (15) coming from the recycling duct not containing a heater, to divert these two substantially horizontal currents into substantially vertical currents and to channel them in the form of a multitude of laminar streams (32, 33) parallel to the vertical axial plane of the tunnel, the streams (32, 33) from one source and the other being in alternate positions and axially offset at least on one edge, in such a manner that their mixing produces an air current comprising two zones (34, 35) at different temperatures in the axial direction and substantially homogeneous in the transverse direction, the less hot zone (35) being oriented on the side where the parallel flow section (4) is located.

Abstract: Device for the continuous dehydration of products of the type comprising a stack of endless belts, travelling in alternate directions, characterized in that, on the one hand, only one (33) of the ducts (33, 34) is provided with a heating means (14) and with a fresh air intake (32), and in that, on the other hand, at each belt level (1, 2, 3, 4 or 5) there is distributed a mixture of a portion of air coming from the circuit with reheating through a first opening (20, 21, 22, 23 or 24) and another portion of air coming from the circuit without reheating through a second opening (27, 28, 29, 30 or 31), the ratio of cross-sections between the first and the second opening being progressively variable and constantly diminishing from the top level (1) down to the bottom level (5).