Heat exchanger

A laminated type evaporator (200) for an automotive air conditioning refrigerant circuit includes a plurality of tube units (201) having a pair of tray-shaped plates (202). Each tray shaped plate includes a shallow depression defined therein, a flange extending about the periphery thereof, and wall disposed at an intermediate location therein and extending a portion of the length of each plate to thereby define a left side and a right side to each plate. A first plate in the pair includes a plurality of projections formed in its shallow depression. The second plate in the pair includes a plurality of projections formed in its shallow depression. The plurality of projections in the first and second plates are engaged by, e.g., inserting one into the other, so that the plates are secured against lateral and radial relative movement.