Interrupted fin for heat exchanger

Abstract

The present invention involves a flat fin heat exchanger configuration with a plurality of louvers and a rib raised above the plane of the fin connecting adjacent tube collars. The raised rib configuration enhances the heat transfer characteristics of the fin, and allows for the use of thinner materials to lower cost without diminishing performance. The exterior fin surface 'scoops' and redirects air flow from the leading edge to the trailing edge of the fin. This 'scooping' effect directs the air flow over and in between the interrupted surfaces, thus breaking up air boundary layer around the fin. The louvers of the fin are oriented relative to the air flow in such a manner that each louver in effect creates another leading edge contributing to a higher heat transfer coefficient. Also, the location of the raised rib also enhances the heat transfer between the fin and the circulated air. The fin collars are also surrounded by a raised portion so that one raised rib and its two adjacent raised portions bordering the collar form a 'dog bone' type shape. The leading and trailing edges are serrated to improve the structural rigidity and create turbulence in the air flow. Also, the leading and trailing edges are oriented at a slight angle, e.g., 12.degree., relative to the plane of the fin. The louvers are oriented at a slightly greater angle than the leading and trailing edges, e.g., 20.degree.-35.degree..