EP1774245B1 - Fully-metal heat exchanger and method for its production - Google Patents

Description

TECHNICAL AREA

The invention relates to a whole-metal heat exchanger, consisting of flat tubes with two narrow - and two broad sides and ribs, which together with the flat tubes form a block, and either at least one tubesheet and a collecting box, wherein edges of the collecting tank with edges of the Tube bottom connected, for example, are soldered, or at least one collecting box, which includes the tube sheet, own, and with spaced projections. Furthermore, the invention relates to a production method for heat exchangers.

STATE OF THE ART

The heat exchanger described above is for example from the DE 198 19 247 A1 known. The projections correspond there with openings in the tube sheets. As a result, a provisional cohesion of the items is provided before performing the soldering process. The cost of soldering auxiliary device can be significantly reduced. A certain disadvantage of the known heat exchanger is that there is still a clear overhang of the tube bottom over the rib-flat tube block, which could be regarded as an unnecessary space requirement. Furthermore, the ratio of the cross sections occupied by the flat tubes is not optimal in comparison with the entire cross section of the heat exchanger or its tube plates, so that improvements are possible with regard to efficient heat exchange.

PRESENTATION OF THE INVENTION

The object of the invention is to provide a heat exchanger which achieves a smaller space requirement with comparatively good thermal-technical values.

As a side effect, a production-friendly, in particular a flexible design can be assumed.

The solution according to the invention results with respect to the all-metal heat exchanger by the use of the features of claim 1. The production method according to the invention is the subject of claim 22. It is envisaged that the projections in the region of the narrow sides engage in the ends of the flat tubes. The projections are preferably located on the opposite longitudinal edges of the header tank.

Preferably means in this case that embodiments may be provided, in which the projections are arranged on the longitudinal edges of the tube sheet, possibly associated with the disadvantage that the tube sheets are expensive and some other advantages do not occur. Another possible construction is that a metallic, frame-like additional part, which has the projections, is provided.

The manufacturing process leads to a number of advantages. The plugged into the flat tube ends projections on both opposite edges of the header hold the flat tubes during the subsequent soldering process to tension, so that the risk of so-called "collapse" of the flat tubes, with the result of insufficient solder joints with the tube sheet has been substantially reduced. Therefore, the invention also allows the use of flat tubes whose broad sides can have larger dimensions and thus avoids the production-technically complicated use of several rows of flat tubes in the direction of the depth of the flat tube rib block. In other words, with the invention, heat exchangers can be made available in a much broader performance spectrum with much less modification effort.

In addition, the above-mentioned advantages of the prior art are retained, i. H. In particular, the cost of soldering auxiliary devices is significantly reduced, since the inserted projections support the cohesion of the mounted items of the heat exchanger.

Because the flat tubes extend over the entire depth of the tubesheet, preferably even beyond, there is virtually no space that would not be available for heat exchange purposes. In other words, the flow-through cross-sectional area of the flat tubes is in a more favorable ratio to the total occupied by the tube sheet surface, which in turn is about equal to the relevant area, which is occupied by the entire heat exchanger.

In addition, the proposed heat exchanger has a higher process reliability in the production, as heat exchangers, which have no tube plates but instead of the tubesheets flared flat tube ends, as for example from DE 195 43 986 A1 or from much older documents are known.

Either the flat tubes are with their narrow sides over the width of the tubesheet and in the protruding region, the projections engage in the ends of the flat tubes. Or the tube plate width is beyond the narrow sides of the flat tubes and in the protruding region, the projections engage in the ends of the flat tubes.

The first alternative mentioned, as mentioned, preferred because it is better to prevent the already mentioned "collapse" of the flat tubes, since in this case the edge of the headers with the projections from the outside rests on the edge of the tube sheet and therefore because the projections against Forces which act in the direction of the broad side, ie transversely to the longitudinal direction of the flat tubes, are particularly resistant. Furthermore, this alternative also appears to be more favorable in terms of creating dense connections.

The projections each touch the narrow sides of the flat tubes from the inside and they are preferably soldered there.

The tubesheet preferably has in a conventional manner bent edges and openings for receiving a respective flat tube end. The openings, however, are proposed to extend into the bent edges.

The tubesheets have only on the two longitudinal sides bent edges, so that they can be produced from a metal strip with any length. The tooling costs and the costs for conversion to different heat exchanger sizes are thereby significantly reduced.

The collecting box has frontal openings. Thus, each collection box turns out to be merely a sheet with two folds, which is also advantageous in terms of manufacturing technology.

The frontal openings of the collecting tank are closed by per se known side parts, which are extended beyond the length of the flat tubes out.

The projections are appropriately shaped so that the insertion thereof into the ends of the flat tubes is assisted. An advantageous development provides to form the projections on the type of incisors. This design allows to better compensate for length tolerances in the flat tubes. Despite the inevitable length tolerances tight connections between the projections and the flat tube ends can be created.

The all-metal heat exchanger can be used everywhere in the widest sense with advantages where a small space requirement with good heat exchange efficiency should be present. The inventor remembers to use such heat exchangers especially as air-cooled intercoolers in motor vehicles, but without excluding any other possible use, especially in the field of motor vehicles.

An all-metal heat exchanger is intended to be a heat exchanger whose constituents referred to in the claims are made of metal, preferably aluminum, regardless of whether later non-metallic parts which could be part of the system are attached to this heat exchanger or Not. For example, with all-metal heat exchangers, which are to be manufactured from formed sheet metal, it is relatively expensive to attach accessories and secure them.

The seated in the flat tube ends projections on a comb-like additional part, such as metal strips or the like., Which is connected to the wall of the header, keep the flat tubes during the subsequent soldering process to tension, so that the risk of the aforementioned "incidence "the flat tubes, with the result of insufficient solder joints in the receiving openings, has been significantly reduced by the provision of the additional part. In addition, the advantages of the prior art are retained, i. H. In particular, the cost of soldering auxiliary devices is significantly reduced, since the strips (additional parts) at the ends have hooks that support the cohesion of the mounted items of the heat exchanger by grabbing over the side panels.

The headers can be formed in one piece or multiple parts. Striking is a part which has a U-shaped cross-section, wherein the base portion is provided with receiving openings for the pipe ends and the two legs form the two walls of the collecting tank. Once the walls have been reshaped and brought together to form a room, one-piece collection boxes are available. If the walls remain essentially flat, a second part is necessary for the formation of a closed space, which is why two-part collection boxes are then present. The receiving openings extend minimally into the walls of the collecting tank.

These projections are also suitably shaped, so that the introduction of the same is supported in the ends of the flat tubes.

The additional part is a comb-like sheet metal strip, which is easy to process by forming technology to produce the additional part. For the purposes of the present invention, the term "strip" encompasses all possible physical formations, so that it is therefore generally possible to speak of an additional part. The mentioned projections on the strips or additional parts may be first projections, in the event that the strip second projections are provided. The second protrusions are then arranged between the first protrusions. The second protrusions improve the assembly or preparation of the heat exchanger for the following soldering process.

The inventive method for producing a whole-metal heat exchanger, wherein flat tubes and ribs are merged into a flat-tube fin block, after which tube plates are attached to the ends of the flat tubes and finally collecting boxes are attached with their edges to the edges of the tube sheets is characterized in that arranged on a component projections in the narrow sides of the flat tubes are inserted in the ends thereof.

Preferably, the longitudinal edges of the header are outside on the longitudinal edges of the tube sheet. The narrow sides of the flat tubes project over the longitudinal edges of the tube bottom, so that the protrusions located on the longitudinal edges of the collecting box can be inserted into the protruding flat tube regions. In this way, the projections hold the flat tubes in a tensioned state.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

zeigt eine Explosionsdarstellung des erfindungsgemäßen Wärmetauschers;

Fig. 2

zeigt eine Frontansicht,

Fig. 3

zeigt eine Draufsicht;

Fig. 4

und 5 zeigen perspektivische Ansichten eines Teils des Wärmetauschers;

Fig. 6

zeigt eine perspektivische Gesamtansicht des Wärmetauschers;

Fig. 7

zeigt eine Einzelheit des Flachrohres;

Fig. 8

und 9 zeigen eine alternative Ausführung;

The invention will now be described in two embodiments with reference to the accompanying drawings.

Fig. 1

shows an exploded view of the heat exchanger according to the invention;

Fig. 2

shows a front view,

Fig. 3

shows a plan view;

Fig. 4

and Figure 5 are perspective views of a portion of the heat exchanger;

Fig. 6

shows an overall perspective view of the heat exchanger;

Fig. 7

shows a detail of the flat tube;

Fig. 8

and Figure 9 shows an alternative embodiment;

The Fig. 10 shows an exploded view of the heat exchanger according to the invention. The FIGS. 11 and 12 show perspective views of the finished heat exchanger. The FIGS. 13 and 14 show perspective views of a portion of the heat exchanger in a mounting situation. The Fig. 15 shows an advantageous embodiment of the projections.

DESCRIPTION OF EMBODIMENTS

All illustrated individual parts of the heat exchanger are made of metal, preferably of aluminum or aluminum alloys, which is expediently coated with a layer of solder. The items such as flat tubes 1, ribs 4, tubesheets 5, 6 manifolds and side panels 30 are made of sheets, which, however, is not excluded that, for example, the flat tubes 1 could also be produced as drawn tubes. The flat tubes 1 have an approximately rectangular cross-section, but the narrow sides 2 can also be curved slightly outwards. In the embodiment shown, internal inserts are located in the flat tubes 1. The flat tubes 1 are then stacked with the ribs 4 to form a flat tube fins block. At the ends of the flat tubes 1 tube sheets 5 are attached, with the ends of the flat tubes 1 are in openings 21 of the tube sheets 5 , where later a dense solder joint is formed. Then the headers 6 are placed, namely, in particular the Fig. 4 can be seen while the projections 11 at the edges 10 of the manifolds 6 in the edge regions of the flat tubes 1, which are formed by the slightly over the edges 20 of the tube sheet 5 protruding narrow sides 2 of the flat tubes 1 inserted. At the edge of the openings 21 in the tubesheets 5 there are preferably passages (not shown) which preferably point away from the collecting box 6 so that the flat tube ends do not protrude inwards in order to ensure low pressure loss of the medium flowing into the flat tubes 1 . Between the openings 21 in the tube sheets 5 webs 22 are present. The webs 22 may be formed profiled to increase their rigidity. Finally, the side parts 30 are attached, which simultaneously close the frontal openings 60 of the collecting tanks 6 . The side panels 30 each have a cup-shaped reshaped at their ends A closure piece that fits into the opening 60 . By means of deformable holding elements 61, which engage in a slot 62 of the side parts, the side parts 30 are pre-fixed and hold the individual parts of the heat exchanger together. In this form, the heat exchanger is substantially prepared to carry out the CAB brazing process. All connections are made in a single pass in a brazing furnace.

The shape of the projections 11 is suitably adapted to the existing in the narrow sides 2 contour of the flat tubes 1 , so that both the insertion is facilitated as well as dense solder joints are provided. This also certain manufacturing tolerances are absorbed. The distance between the projections 11 at the edge of the manifolds 6 corresponds to the distance between the flat tubes 1 in the row or with the height of the arranged between the flat tubes 1 ribs 4. Here, certain tolerances must be allowed, however, by the appropriate shape of the projections 11th can be compensated. (see the description of the Fig. 15 and 16 further down)

The headers 6 are particularly easy to manufacture, simple shape. Only two folds are necessary to form the two longitudinal walls and a transverse wall. For example, connecting pieces 70 can be easily realized by forming processes.

It should also be particularly production-friendly tube sheets 5 are used, which are made of endless tape and only need to be cut to the appropriate length, because they have no bevelled edges on their faces. There are therefore no expensive drawing tools needed. Here is an indication of the Fig. 4 and 5 at. There it can be seen that at the edge 10 of the collecting tank 6 with the projections 11 comparable approach 100 is present. This cooperates with the corresponding cutout 101 on the edge 20 of the tube plate 5 and ensures there dense solder joints. From the Fig. 5 can also be seen that the openings 21 extend in the tube sheet 5 into the edge 20 , which is indicated by the reference numeral 22 . Therefore, the tubesheets 5 during assembly can also be pushed transversely to their longitudinal direction, or in the direction of the broad sides 3 of the flat tube ends, onto the same. In the prior art, this requires a movement in the longitudinal direction of the flat tubes. There is talk of "pulling up" the tubesheets.

especially the Fig. 3 and 6 show in a view of one of the side members 30 that there are no lateral projections of the tube sheets 5 over the flat tube ribs block. The width of the side parts 30 corresponds approximately to the extent of the broad sides 3 of the flat tubes. 1

It should also be noted that the heat exchanger according to the invention allows a fairly easy access from the outside to soldering critical connections. Such critical connections are the flat tube tube sheet connections. If there are any leaks after the soldering process has been carried out, the corresponding points can be simply aftertreated and eliminated in a second soldering pass as they are largely accessible. In heat exchangers of the prior art, such a thing is often not possible, which is expressed by high reject rates.

The Fig. 7 schematically shows a single flat tube 1, namely a view of the flat tube end. Such flat tubes 1 are present in the desired number of heat exchangers. In each flat tube 1 , two projections extend 11. The penetration depth needs to be only a few millimeters, 10 - 15 mm is already more than enough. Practically it will be less. It is understood that the one projection 11 is located at one edge of the header tank 6 and the other projection 11 at the opposite other edge 10 of the header tank 6. The projections 11 are close to the narrow sides 2 of the flat tube 1 from the inside. In the flat tubes 1 is an inner insert 80, as is typical in particular for charged with cooling air charge air cooler. In other applications, an indoor use is completely dispensed with. In practice, it is often difficult to insert the inner inserts 80 into the flat tubes 1 in such a way that as far as possible there is no bypass for the through-flow of charge air in the region of the narrow sides 2 , which has a disadvantageous effect on the heat exchange. As the Fig. 7 shows, the projections 11 have a favorable effect on the reduction of the harmful bypass, which comes as a further advantage of the invention to bear. The small gaps in the corners of the flat tube 1 have their cause in the representation. In practice, they are not available or are securely closed during the soldering process. The mentioned gaps will also level when inserting the projections 11 , because the projections 11 hold both broad sides 3 in the direction of the arrow under a certain tension.

The 8 and 9 now show an alternative design, in which the projections 11 are arranged on the tube sheets 5 . In this case, the tubesheets 5 must be mounted in the tube longitudinal direction, at the same time the projections 11 are inserted into the flat tube ends 1 . Thereafter, the headers 6 and the side members 30 are attached and mounted.

At least in the embodiment, which in the Fig. 10 - 14 is shown, one-piece headers 6 were provided. In any case, however, it is provided that the collecting boxes 6 also include the tubesheets 5 , so that therefore no classical tubesheets are provided as a single part, which can be taken from the mentioned figures. The collecting box 6 has a base section 106 , from which two bent walls 107 of the collecting tank 6 depart. The walls 107 are deformed and they can be connected by means of a longitudinal weld, not shown, to form the header 6 . In the base portion 106 receiving openings 21 are provided for the flat tube ends, which should therefore match the distances of the flat tubes 1 with the distances of the receiving openings 21 . A quite striking feature is that the receiving openings 21 extend into the walls 107 in, ie they extend to just over the bending edge of the walls 107 at the base portion 106, which clearly enough from the Fig. 14 can be seen at the reference numeral 22 . In the embodiments shown, a strip (additional part) 110 is provided on all the walls 107 of the two collecting boxes 6. On the walls 107 of a collecting box 6 , the strips 110 have additional functions, such as holding functions 90 for accessories (not shown). The provision of strips 110 on all walls 107 is not an inevitable measure. In particular, it is advantageous to provide a strip 110 whenever additional functions 70 are to be fulfilled. In principle, there would be no reason in the present exemplary embodiment to dispense with the narrow strips 110 on the walls 107 of the left collecting tank 6, which do not have any additional functions, and to provide the solution described above there, ie the projections 11 would then be directly on the walls 107 of the collecting tank 6 and there would be tubesheets as individual parts, as shown in the figures.

Another advantage of the strip 110 comes from the Fig. 12 out. One can see there that the strip 110, with the mentioned additional functions is formed, can also make a contribution to the strength of the collecting tank 6 . You see in the Fig. 12 in that the strip 110 extends over a substantial part of the wall 107 of the collecting box and is soldered to this wall 107 .

From the FIGS. 13 and 14 the formation of the strip 110 can be seen more clearly with respect to the protrusions 11 arranged at intervals. The projections 11 can be provided with such a contour that the sliding of the same is facilitated in the flat tubes 1 . Between the projections 11, which are first projections 11 , are each second projections 12. As can be seen, a respective second projection 12 has been arranged between two first projections 11 . The second protrusions 12 provide a counter-momentum of the strip 110 which otherwise, when the first protrusions 11 are in the flat tube ends, could tend to stand off the wall 107 , which is undesirable. Since the second projections 12 rest against the ribs 4 from the outside, this is prevented, or at least counteracted.

From the FIGS. 13 and 14 It is further apparent that it is advantageous to form at the ends of the strip 110 a hook 13 which is adapted to hold the side member 30 to the outer rib 4 firmly. This also supports the cohesion of the entire heat exchanger before soldering. Furthermore, it also suppresses the above-mentioned "sticking out" of the strip 110 from the wall 107 . It can also be used in the Fig. 1 With 61 and 62 shown brackets, which should hold the side panels 30 in the frontal openings 60 of the collecting tank 6 , are omitted, which is also a manufacturing advantage.

The Fig. 15 shows a section with only one projection 11. The projections 11 have been performed on the type of cutting teeth 111 . As a result, length tolerances in the flat tubes, which are approximately in the range of +/- 1.0mm are better absorbed. In these projections 11 sharp edges 112 were formed, which are also in the radii, d. h in the region of the transition from the projection 11 in the wall of the collecting tank 6 or the additional part or the tube bottom extend. The sharp edged edges 112 intersect these ends when inserting the projections 11 into the flat tube ends, somewhat at the flat tubes which are in the upper length tolerance range, and "fold" these ends slightly outwards. That is from the Fig. 16 easy to recognize at k. The middle tube is slightly longer there than the other two tubes. The sharp edge of the projections 11 is produced for example by cold forming. The difference in thickness between the projections 11 and the wall of the flat tubes supports this procedure. The wall of the collecting box 6, from which the projections 11 are formed, for example, may be about 1.0 - 2.0mm thick while the thickness of the

Wall of the flat tubes may be in the range of 0.05 - 0.25mm.

Overall, the invention accordingly provides an innovative product which, compared to the state of the art, leaves only little to be desired.

Claims (23)

1. Fully-metal heat exchanger, composed of flat tubes (1) having two narrow and two wide sides (2, 3) and of fins (4) which, together with the flat tubes, form a block, and which fully-metal heat exchanger has either at least one tube base (5) and a collecting tank (6), with edges (10) of the collecting tank (6) being connected, for example soldered, to edges (20) of the tube base (5), or at least one collecting tank (6) which contains the tube base, and having projections (11) which are arranged at intervals,
   characterized in that the intervals of the projections (11) correspond to the intervals of the flat tubes (1), so that the projections (11) engage in the region of the narrow sides (2) into the ends of the flat tubes (1).
2. Fully-metal heat exchanger according to Claim 1, characterized in that the flat tubes (1) protrude with their narrow sides (2) beyond the width of the tube base (5), and in the protruding region, the projections (11) engage into the ends of the flat tubes (1).
3. Fully-metal heat exchanger according to Claim 1, characterized in that the tube base width protrudes beyond the narrow sides (2) of the flat tubes (1), and in the protruding region, the projections (11) engage into the ends of the flat tubes (1).
4. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the projections (11) in each case make contact with the narrow sides (2) of the flat tubes (1) from the inside, and are preferably soldered there.
5. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the projections (11) are preferably arranged at the longitudinal edges (10) of the collecting tank (6).
6. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the tube base (5) has edges (20), which are bent in a way known per se at the opposite longitudinal sides, and openings (21) for receiving in each case one flat tube end (1), with the openings (21) extending into the bent longitudinal edges (20).
7. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the tube bases (5) have edges (20) bent only at the two longitudinal sides, so that said tube bases (5) can be produced from one sheet-metal strip of any desired length.
8. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the collecting tank (6) has end-side openings (60).
9. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the heat exchanger has side parts (30), which are known per se, which extend over the length of the flat tubes (1) and close off the end-side openings (60) of the collecting tanks (6).
10. Fully-metal heat exchanger according to Claim 1, characterized in that the projections (11) are arranged on the tube base (5), or in that a frame which has the projections (11) is inserted.
11. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the projections (11) are formed on an additional part (110) which extends along the wall (107) of the collecting tank (6) and is connected thereto.
12. Fully-metal heat exchanger according to Claims 1 and 11, characterized in that the collecting tank (6) has two walls (107) which are bent away from a base section (106) which is formed with receiving openings (21) for the tube ends.
13. Fully-metal heat exchanger according to Claim 12, characterized in that the receiving openings (21) extend into the walls (107) of the collecting tank (6).
14. Fully-metal heat exchanger according to Claim 11 or 12, characterized in that the additional part (110) bears externally approximately flat against the wall (107) of the collecting tank (6).
15. Fully-metal heat exchanger according to one of the preceding Claims 11-14, characterized in that the additional part (110) is provided with further functions, for example with retaining functions (90) for accessories or the like.
16. Fully-metal heat exchanger according to one of the preceding Claims 11-15, characterized in that the additional part (110) can be provided with a contour which corresponds to the contour of the wall (107) of the collecting tank.
17. Fully-metal heat exchanger according to one of the preceding Claims 11-16, characterized in that the projections (11) are first projections (11), with the additional part (110) having second projections (12) between the first projections (11).
18. Fully-metal heat exchanger according to one of the preceding Claims 11-17, characterized in that the additional part (110) is formed at the end with a hook (13) or the like which is suitable for fixing a side part (30) of the heat exchanger.
19. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the projections (11) are shaped in such a way, for example conically, as to assist their insertion into the ends of the flat tubes (1).
20. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the projections (11) are formed in the manner of incisors (111).
21. Fully-metal heat exchanger according to one of the preceding claims, characterized in that the heat exchanger can preferably be used as an air-cooled charge air cooler.
22. Method for producing a fully-metal heat exchanger, having the following steps:

    flat tubes and fins are placed together to form a flat-tube/fin block;

    tube bases are placed on the ends of the flat tubes;

    collecting tanks are placed with their edges on the edges of the tube bases,

    characterized in that projections (11) which are arranged on a component are inserted, in the region of the narrow sides (2) of the flat tubes (1), into the end thereof.
23. Production method according to Claim 22, characterized in that the longitudinal edges (10), which have the projections (11), of the collecting tank (6) are preferably attached to the edges (20) of the tube base (5) from the outside, with the projections (11) being inserted into the ends of the flat tubes (1).

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