Heat exchanger unit formed of a plurality of modular units including connection couplers

Heat exchanger unit for the climatization of buildings, in which an extruded tubular element of radiator of an aluminum alloy adapted for extrusion, has an inner longitudinal canal and outer fins, die-cast T-shaped header elements of die-casting aluminum alloy are mounted by means of an interference engagement on each end of the tubular element in fluid communication with the inner longitudinal canal of said tubular element, and connection couplers sealingly connect headers of adjacent units to each other to form a heat exchanger characterized in that

• the header element comprises on the outer surface of the vertical branch of T shape, an abutment for an abutment engagement with an end portion of the tubular element, a circular groove adjacent to said abutment and an O-ring gasket housed into said circular groove, the tubular element having the end portion thereof tapered and bent which is sealingly engaged to said O-ring;
• said header element further comprises, projecting from the outer surface of the horizontal branch of the T shape, a plurality of pins for engagement with said couplers;
• and said connection coupler is provided with cam slots with an open end at the end of said coupler and an inclined flank directed to the middle of the coupler from said open end, for a cam force fit of said pins on the header elements and said flank on the cam slots, in a bayonet coupling of header elements of adjacent units.