The present invention relates to a flat tube for heat exchangers, such as, for example, charge air coolers for motor vehicles. The heat exchanger tubes can have two narrow sides and two broad sides and can be manufactured from two contoured, continuous strips having a relatively large curve on one longitudinal edge of each strip and having a relatively small curve on the other longitudinal edge of each strip. The two strips can be arranged with respect to one another to form the walls of the flat tube, in such a way that the relatively large curve of the longitudinal edge of one strip holds in itself the relatively small curve of the longitudinal edge of another strip (and vice versa) in order to form the narrow sides of the flat tube.
Flat tubes are known from a number of older applications. One of the applications is German Patent App. No. DE 10 2006 006 670.7. FIG. 1 of German Patent App. No. DE 10 2006 006 670.7 shows a flat tube in cross section. This flat tube has a corrugated inner part z in addition to the features enumerated above. The flat tube is defined by an extremely thin wall thickness, for example in the range from 0.03 mm-0.15 mm or slightly above. Such flat tubes have already been manufactured by the applicant and installed on a trial basis in heat exchangers. Until now, such heat exchangers have successfully passed all the validation phases so that they are expected to be made commercially available soon.
In some flat tubes, undesired changes in shape of the not yet brazed flat tubes occurs within the course of manufacture. The flat tubes are brazed later, after they have been pre-mounted in the heat exchanger core using fins. The changes in flat tube shape are possibly due to stresses present in the material (e.g., aluminum or steel in sheet form), or are generated by the necessary shaping of the strips. The changes in shape can lead to unsatisfactory braze connections, but they can also, for example, impede the joining to the corrugated inner part z (see
In the already mentioned
One independent object of the present invention is to eliminate or alleviate the above-described disadvantages.
According to one aspect, there is provision for strips to be embodied with corresponding contoured portions which extend in the longitudinal direction of flat tubes and which improve cohesion of flat tubes formed from the strips by virtue of the fact that the contoured portions interact with a respective other strip. This at least largely prevents the flat tubes from springing apart or being able to be pushed apart during their processing to form a heat exchanger, that is to say before the brazing process of the heat exchanger is carried out. The preconditions for better brazing quality are thus provided.
In some embodiments, two strips are particularly preferably embodied in an identical way. Contoured portions are preferably embodied as beads, as a bend, or the like. The contoured portions are preferably arranged at the start and/or at the end of the curves.
In a case presented by way of example, there is provision for the contoured portions to be arranged approximately at the start of the large curve of one strip and to interact with the end of the small curve of the other strip. In another case also presented by way of example, there is provision for the contoured portions to be arranged approximately at the start of the large curve of one strip and to interact with a section of the small curve of the other strip. In such embodiments, the small curve can be embodied with multiple layers in an extremely favorable way, as a result of which even more stable narrow sides can be produced.
In yet another case, there is provision for the contoured portions to be arranged approximately at the start of the small curve and approximately at the end of the large curve of the two strips, in which case they interact in such a way that the contoured portions fit into one another approximately.
In an advantageous development, there is provision for the large curves and/or the small curves to be embodied in multiple layers. The multiply-layered structure can be generated by folds in the curves. In this way it is possible, as mentioned, to considerably strengthen the narrow sides of the flat tube.
The present invention will be described in a plurality of exemplary embodiments by means of the appended sketches. Other aspects of the present invention will become apparent by consideration of the detailed description and accompanying drawings.
The individual figures show the following:
a and 2b show a problem with prior art flat tubes.
a-d show a first exemplary embodiment for solving the problem shown in
a-d show a second exemplary embodiment for solving the problem shown in
a-d show a third exemplary embodiment for solving the problem shown in
a-d show a fourth exemplary embodiment for solving the problem shown in
a-d show a fifth exemplary embodiment for solving the problems shown in
Before any embodiments of the present invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the accompanying drawings. The present invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
Five exemplary embodiments have each been represented with four illustrations which have been designated by the letters a-d. The illustration a in each case shows an enlarged view of a large or small curve B, b of a contoured strip. The illustration b in each case shows one of the contoured strips. The illustration c in each case shows a narrow side 1 of a flat tube formed from a large curve B of the one strip and a small curve b of the other strip. Finally, the illustration d in each case shows the respective flat tube as a view which corresponds to a cross section through the flat tube.
In all the exemplary embodiments shown, an inner part z may be present, such an inner part z shown in
In each of the illustrated exemplary embodiments, the two strips x and y are substantially identical, and are arranged in a laterally transposed fashion with respect to one another in order to form a flat tube. In addition, the thicknesses of the strips can be approximately in the range from about 0.03 mm to about or slightly above 0.15 mm. In addition, the strip thickness for an inner part (e.g., z), if one is provided, can be in the range from about 0.03 mm to about 0.09 mm. In addition, the flat tubes can be flat tubes for charge air coolers which are used in motor vehicles. All other heat exchanger applications and fields of use are not excluded. The large or relatively large curve B is referred to herein as such because it is suitable for holding in itself (i.e., in nested relationship) the other curve which has been referred to as the small or relatively small curve b. In fact, in view of the extremely thin sheet metal thicknesses that can be used for the strips, there may be no size differences between the curves B, b which can be perceived at first sight.
The first exemplary embodiment according to
In the exemplary embodiment according to
In the exemplary embodiment according to
In the exemplary embodiment according to
In the exemplary embodiment according to
The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention as set forth in the appended claims.
Number | Date | Country | Kind |
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10 2007 006 664 | Feb 2007 | DE | national |
This is a continuation application of and claims priority to PCT Patent Application No. PCT/US07/085921 filed on Nov. 29, 2007. Priority is also hereby claimed to German Patent Application No. DE 10 2007 006664.5 filed Feb. 10, 2007. The entire contents of both prior-filed patent applications are incorporated herein by reference.
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Entry |
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PCT/US2007/085921 International Search Report and Written Opinion dated Apr. 30, 2008 (7 pages). |
First Office Action from the State Intellectual Property Office of China for Application No. CN 200780051159.4 dated Mar. 24, 2010 (English Translation—3 pages). |
German Patent and Trademark Office Search Report Application No. 102007006664.5, dated Oct. 26, 2007 (English Translation and Original—11 pages). |
Number | Date | Country | |
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20100025029 A1 | Feb 2010 | US |
Number | Date | Country | |
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Parent | PCT/US2007/085921 | Nov 2007 | US |
Child | 12538365 | US |