Patent Publication Number: US-8985193-B2

Title: Heat exchanger

Description:
This nonprovisional application is a continuation of International Application No. PCT/EP2010/061365, which was filed on Aug. 4, 2010, and which claims priority to German Patent Application No. DE 10 2009 038 297.6, which was filed in Germany on Aug. 21, 2009, and which are both herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a heat exchanger, particularly a gas cooler, having at least one collecting tank, which extends in a longitudinal direction and comprises a base and a cover and has at least two longitudinal channels, substantially circular in cross section, which are spaced apart at least in sections by at least one longitudinal partition wall formed by the base and/or cover, whereby the base, at at least one of its edge regions running in the longitudinal direction, has a rim by means of which the base overlaps on the outside an edge region, running in the longitudinal direction, of the cover or whereby the cover, at at least one of its edge regions running in the longitudinal direction, has a rim by means of which the cover overlaps on the outside an edge region, running in the longitudinal direction, of the base. 
     2. Description of the Background Art 
     WO 2004/088234 A2 discloses a generic heat exchanger in which the rim is formed by a continuous tab. After the cover is placed on the base, the rim is bent or folded in order to fix both parts to one another before a soldering process. This calls for a high material requirement and high forces for the bending or folding, however, whereby the joining forces, which predominate after the bending or folding between the base and cover, are small owing to the elastic deformation of the rim. 
     DE 10 2006 053 702 A1 discloses a collecting tank in which the rim is formed by individual tabs. Here as well, after placement of the cover on the base, the rim is bent or folded to fix both parts to one another. The joining forces between the base and cover are small, however, because of the thinning of material and elastic deformation of the rim. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a heat exchanger, which is constructed simply and expediently with a secure joining and can be produced cost-effectively. 
     The object is attained by a heat exchanger of the invention, in which the respective rim in the longitudinal direction has a plurality of peened portions, by means of which said rim is deformed in the area of each individual peened portion in the direction of the collecting tank center and fixes the base and cover to one another. Preferably, the cover and base are stamped from a sheet metal blank and each have a substantially w form or ω form in cross section. Because of this form, the base and cover are in contact in their outer areas and in their center, as a result of which a longitudinal partition wall is formed. 
     The two opposite rims can be basically angled outward in the areas in which they have no peened areas. It is preferred, however, that the two rims run parallel to one another in the area in which they have no peened areas. It is of particular advantage that through the plurality of peened portions a strong joining of the cover and base is attained with low material usage. 
     It has proven advantageous, when the plurality of peened portions is arranged symmetrical relative to the collecting tank center. As a result, the joining of the cover and base has a symmetric force profile, which increases the quality of the joining. 
     In a refinement of the invention, two peened portions, adjacent in the longitudinal direction, have the same or different widths. Moreover, it has proven advantageous, when the peened portions arranged in the longitudinal direction have a similar or different distance to one another. In areas of the collecting tank in which, because of the expected stress, a stronger joining of the collecting tank is necessary, this can be assured in a simple manner by increasing the width of the peened portion or by the number of peened portions within the relevant area. The geometry of the individual peened portions is basically arbitrary in this case. Straight portions and angular or round designs are possible. 
     Further, it has proven advantageous, when an individual peened portion has a width of 0.5-6 mm, particularly 0.75-5 mm, particularly 1-4 mm. Point peened portions are achieved in this way, whereby the force necessary for this to produce the peened portion is reduced. 
     In a refinement of the invention, one peened portion or a plurality of peened portions forms a seat for at least one connecting piece, particularly a flange or retainer. The connecting piece, particularly flange or retainer, can be hooked, for example, into the peened portion. It is preferable, however, that the connecting piece is clamped by the peened portion. 
     Advantageously, the base and the cover are soldered together. As a result, the heat exchanger can withstand high pressures and be used, for example, in a CO2 refrigeration circuit. 
     Further, it is provided in a refinement of the invention that the heat exchanger has a plurality of flat tubes forming a heat exchange surface, whereby the flat tubes have tube ends and the base has openings, corresponding to the number of flat tubes, for receiving the tube ends. 
     It has proven advantageous, when the rim of the base is higher than the outer edge of the cover or the rim of the cover is higher than the outer edge of the base. The rim of the base engages behind the cover in the area of a peened portion or the rim of the cover engages behind the base in the area of a peened portion. In such cases, it is preferred if the height of the rim of the base over the edge of the cover or the height of the rim of the cover over the edge of the base is 0.5-4 mm, particularly 0.75-3 mm, particularly 1-2.5 mm, particularly 1-1.5 mm. 
     Ultimately, an exemplary embodiment of the invention is preferred in which the peened portions in the corner areas form a positioning device for the collecting tank in the longitudinal direction. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
         FIG. 1  shows a perspective view of a collecting tank of a heat exchanger of the invention; 
         FIG. 2  shows a side view of the collecting tank according to  FIG. 1 ; 
         FIG. 3  shows a plan view of the collecting tank according to  FIG. 1 ; 
         FIG. 4  shows a sectional view along section I-I according to  FIG. 3 ; and 
         FIG. 5  shows a sectional view along section II-II according to  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     The figures show an assembly of a heat exchanger, provided as a whole with the reference number  2 , particularly a gas cooler. Heat exchanger  2  comprises a collecting tank  6 , which extends in a longitudinal direction  4  and which is formed from a base  8  and a cover  10 . Base  8  and cover  10  are stamped out of a sheet metal plate and have a w- or ω-shaped cross section. Base  8  and cover  10  contact one another in their edge regions  12  and in their center and there form an at least almost closed longitudinal partition wall  14  for longitudinal channels  16  extending in the longitudinal direction  4  ( FIGS. 4 and 5 ). 
     In the exemplary embodiment shown in the figures, base  8  at its edge regions  12 , extending in the longitudinal direction  4 , has a rim  18 , which overlaps cover  10  on the outside. In the longitudinal direction  4 , rim  18  has a plurality of peened portions  20  at which rim  18  of base  8  is deformed in the direction toward the center of collecting tank  6  and lies against cover  10 , as a result of which cover  10  and base  8  are fixed to one another. 
       FIGS. 1 ,  2 , and  3  show collecting tank  6  from different views. Rims  18  run parallel to one another and are higher than the outer edge  22  of cover  10 . Peened portions  20  lie against the outer edge  22  of cover  10 , so that base  8  engages behind cover  10  in the area of peened portions  20  perpendicular to the longitudinal direction  4 . Peened portions  20  are arranged symmetrically to the center of collecting tank  8  and have substantially the same width. Peened portions  20  have a geometry, which has predominantly straight and angular sections. 
     In the shown exemplary embodiment, connecting piece  24  is connected to collecting tank  6  via a seat  26  formed by one of the peened portions  20 . To this end, the distance of two peened portions  20 , adjacent in the longitudinal direction  4 , is smaller than in areas in which no connecting piece  24  is accommodated. 
     On the side of base  8 , said side facing away from rim  18 , openings  28  are arranged, in which a plurality of flat tubes (not shown) forming a heat exchanger surface can be inserted with their tube ends. 
     The joining of heat exchanger  2  is explained below with reference to  FIGS. 4 and 5 . 
     Base  8  and cover  10  are stamped out of a sheet metal plate and formed into a w or ω shape. To join the two parts, cover  10  is arranged within base  8  and overlapped by it on its edge regions  12  from outside by rim  18 . Cover  10  and base  8  contact one another in each case in their center and as a result form the longitudinal partition wall  14 , which spaces apart the two longitudinal channels  18 . With the introduction of peened portions  20  into rim  18 , base  8  and cover  10  are pressed against one another and joined together. 
     In the shown exemplary embodiment, rim  18  of base  8  is higher than the outer edge  22  of cover  10  and runs parallel to the opposite rim  18  in the areas in which there is no peened portion  20 . As a result, peened portion  20  engages behind cover  10  and presses it against base  8 . 
       FIG. 5  shows a section along line II-II according to  FIG. 3  in which a connecting piece  24  is arranged at the level of a peened portion  20  formed as a seat  26 . Connecting piece  24  lies on one side against the outer edge  22  of cover  10  and is clamped laterally by peened portions  20 , so that it is fixed on collecting tank  6 . 
     A process-reliable joining of collecting tank  6  including connecting pieces  24  is achieved by peened portions  20 . 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.