Heat exchanger

A cross finned tube heat exchanger comprising:

• a multiplicity of fin plates of a suitable area arranged in substantially parallel, closely spaced relation;
• and
• a plurality of heat transfer tubes passing through aligned openings in said fin plates and kept in intimate contact with said fin plates to allow a heat transfer medium flowing through said heat transfer tubes to exchange heat with another heat transfer medium flowing across the surfaces of said fin plates;
• wherein the improvement comprises:
• a multiplicity of stepped louvers formed on a wall of each fin plate between the adjacent heat transfer tubes of the same row, said stepped louvers having, in a direction substantially at right angles to a direction of flow of the heat transfer medium across the surfaces of the fin plates, thin strips of substantially similar width, said thin strips being formed from the plane of each of said fin plates into stepped louvers generally at right angles to the direction of flow with said another heat transfer medium, said stepped louvers having at least two walls disposed substantially parallel to one another and at least one tilting rise wall connecting said at least two walls, said strips connected at their ends to each of said plates said stepped louvers each having a rear edge varying in vertical position from a front edge of the next following stepped louver in a given row.