Patent ID: 7428920

Claim:
In a heat exchanger having at least one pair of adjacent tubes with a fin extending therebetween, the fin including at least one louver arrangement for heat transfer from a medium located in the tubes to a second medium flowing outside of the tubes and over the fin, the louver arrangement comprising: an inflow part, an outflow part, both the inflow and outflow parts each having a series of adjacent louvers including an outside louver, at least one intermediate louver, and an inside louver, a plurality of passage slots formed in the fin and at least one passage slot being located between each adjacent louver, the inside louver of the inflow part being connected to the inside louver of the outflow part, all of the louvers of the inflow part being arranged inclined relative to all of the louvers of the outflow part such that the inflow part and the outflow part are symmetrical to one another, all of the louvers being provided with louver geometry elements of length L, width B, and an angle of inclination α, wherein the angle of inclination of at least one of the louvers of the inflow part is different from the angle of inclination of the remaining louvers of the inflow part and, proceeding from the outside louver of the inflow part to the inside louver, of the inflow part, the angles of inclination of the louvers progressively increase and thereafter decrease.