Cross-fin tube type heat exchanger

Abstract

A cross-fin tube type heat exchanger having a large number of parallel fins and a plurality of heat transfer tubes extended through and fixed to the fins, so that heat may be exchanged between a first heat exchanging medium flowing through the heat transfer tubes and a second heat exchanging medium flowing along the surfaces of the fin, across the walls of the heat transfer tubes and through the fins. In the portions of each fin between adjacent heat transfer tubes of the same row, formed are a number of slits perpendicular to the direction of flow of the second heat exchanging medium. Each elongated section defined between each pair of adjacent slits is bent along its breadthwise bisector line and is raised in the form of a bridge to constitute an upwardly convexed louver element. The upwardly convexed louver element may have a cross section with an obtuse apex angle, or may have an arcuate cross section. The successive louver elements are arrayed in the direction of flow of the second heat exchanging medium in a manner of corrugation, or alternately staggered in the heightwise direction so that the edges of adjacent louver elements may be staggered in the heightwise direction. The fins having louver elements thus constructed cause a turbulency of the flow of the second heat exchanging medium to effectively prevent boundary layers of the latter from growing, thereby to ensure a higher efficiency of the heat exchange. Also increased stiffness or rigidity of the fin is obtained thanks to the provision of upwardly convexed louver elements.