Plate heat exchanger

A plate heat exchanger with parallel and counterflow circulation of heat-exchange fluids, said heat exchanger comprising:

• a stack of a predetermined number of ribbed plates of the same size, the plates of said stack being clamped against one another between two flanges, said ribbed plates having openings in their corners defining, within the stack, respective supply and outlet channels for the heat-exchange fluids, the plates being made of bulk graphite, previously impregnated with a resin waterproofing material, said stack of ribbed plates further including a system of ducts between each pair of adjacent plates, said system of ducts fluidly connecting said respective supply and outlet channels and each duct of said system of ducts varying in cross-sectional dimensions between the channels to control acceleration of the heat exchange fluids and optimize the rate of heat exchange, wherein at least one of two faces of each of the plates has a profile including:
• distribution regions A consisting of a plurality of half-ducts extending substantially radially over a sector between two openings of the plate corresponding to said respective supply and outlet channels, said half-ducts being formed by a machining process;
• and
• a heat-exchange region B, connecting the two distribution regions A and including a plurality of machining-formed obstacles to the progression of the fluid circulating between two adjacent plates, thereby forming said system of ducts and points of bearing of one respective plate on the immediately adjacent plate.