Corrugated heat exchange elements in the present sense are the so-called corrugated ribs that are inserted in air-cooled radiators between the flat tubes arranged in a row, in order to guarantee heat exchange between the medium in the flat tubes and the cooling air flowing through the corrugated ribs. The mentioned heat exchanger walls are the broad sides of the flat tubes in this case. The crests are designed arc-like.
Other corrugated heat exchange elements are often referred to as sheets, or also as internal inserts, and are situated within the tubes or in channels formed by plates, for example, in plate heat exchangers that are encountered as oil coolers or the like. In such cases, the heat exchanger walls are the individual plates stacked one in the other. The crests are generally bent in a U-shape.
The heat exchanger elements (corrugated ribs) defined in the preamble are known from U.S. Pat. No. 3,298,432. The structures in the flanks in the US document are very fine ribs that run obliquely in the fashion of a herringbone pattern. The pattern is embossed into the metal strip and the corrugated shape of the corrugated rib is then produced, so that the alignment direction of the structures in one side intersects the alignment direction of the structures in the following side. Since the structures in the US document are supposed to be very fine, improved efficiency of heat exchange is produced in the region near the wall, but a detectable additional effect can scarcely be established by their intersection. Because the pattern is embossed flat in the entire metal strip, it is also located at the crests of the corrugated rib, so that the heat-conducting connection with the heat exchanger walls can be adversely affected. In addition, this very fine structuring can lead to a poor soldering result.
The corrugated ribs in DE 195 03 766 C2 have a similar herringbone structure, in which several herringbone structures are arranged one behind the other there, because of the greater width of the metal strip, so that parallel zigzag lines are produced. The herringbone pattern is much coarser than that from the first-named document. Intersection of the alignment direction from flank to flank is not prescribed in the German document.
The described heat exchanger elements according to the task of the present invention are supposed to be modified so that they offer an additional improvement with respect to heat exchange efficiency.