Abstract: A plate heat exchange for homogenous fluid flows between ducts is provided. The plate heat exchanger includes a plurality of primary plates, wherein are made a plurality of primary passages; a plurality of secondary plates, wherein are made a plurality of secondary passages; first and second collectors for supplying secondary fluid and a collector for discharging the secondary fluid, made in the primary and secondary plates and extending substantially perpendicularly to the primary and secondary plates, the primary and secondary plates being parallel to a determined longitudinal axis and having a common middle plane containing the longitudinal axis; the secondary discharge collector is located at a first longitudinal end of the primary and secondary plates in the middle plane, the first and second secondary supply collectors being located at a second longitudinal end of the primary and secondary plates opposite to the first, symmetrically relatively to the middle plane and away from the middle plane.