EP1376043B1 - Heat exchanger with diffuser - Google Patents

Description

The invention relates to a heat exchanger with a diffuser for introducing a medium into flat heat exchanger tubes, wherein the diffuser has a wall which extends along the ends of a stack of flat heat exchanger tubes and which is connected to the ends by means of soldering and further according to the The preamble of claim 1 is formed

For example, from the WO 00/75591 , but also from a variety of other documents, such a heat exchanger with a collection box is known. The wall which extends along the ends of the heat exchanger tubes, there is undeformed, that is just running through, and the end faces of the two tube halves flat heat exchanger tubes are slotted in the connecting portion of the tube halves a short distance, so as to form a joint, in the wall of the collecting box is used to make the connection there by means of soldering. It may be assumed that the tight connection of the wall to the ends of the stack of flat heat exchanger tubes will not be without difficulty, especially since the wall thickness of the heat exchanger tubes is substantially less than 1.0 mm. Furthermore, it does not appear to be provided there that a prefixing of the prefabricated for soldering heat exchanger is possible by means of the collecting tank. The prefixing seems, however, with the solution of the DE 197 22 097 A1 be reached because there the two longitudinal walls of the header tank and the narrow walls of the heat exchanger tubes are deformed wave-shaped, so that they correspond with each other. However, in the heat exchanger shown there, it is difficult to realize a tight connection of the wall of the header tank to the butted areas between the heat exchanger tubes.

Other documents that show something similar are for example the EP 775 884 A2 and the EP 1 139 052 A2 ,

Other heat exchangers having the features of the preamble are the so-called caseless plate heat exchangers. This is especially the EP 0 992 756 A2 called. The difference between the heat exchangers described above and the shellless plate heat exchangers is that in the former between the flat heat exchanger tubes corrugated fins or the like are arranged, through which cooling air often passes freely, while in the plate heat exchangers, the heat exchanger tubes by means of deformed Heat exchanger plates are formed, which are stacked together so that heat exchanger tubes for different media directly adjacent to each other. In the last-mentioned document, the ends of the stack of heat exchanger tubes open in a tubesheet. At the edge of the tubesheet, the collection box or the diffuser is fixed circumferentially with its wall.

The heat exchanger from the US 4,183,402 has a collecting box with a wall which is connected at its two longitudinal sides in each case with a sealing part. The seal parts have a wave contour corresponding to a corresponding contour on the stack to be tightly attached thereto.

From the DE 199 27 607A1 Finally, another according to the preamble of claim 1 trained intercooler with a coolant inlet and a coolant outlet shows. The intercooler diffuser has a circumferential wall which extends around the entire circumference of the end of the stack.

The object of the invention is to develop a heat exchanger with a collecting box or a diffuser, the wall of which can be tightly connected to the ends of a stack of flat heat exchanger tubes and which should be designed so that it can fix the prepared for carrying out the soldering stack ,

The solution according to the invention is the subject of claim 1.

The wall of the header or diffuser extends circumferentially around the entire circumference of the end of the stack of flat heat exchanger tubes and has elevations and / or depressions and / or slots. The ridges and / or slots correspond to protrusions on the periphery of the stack. The recesses correspond to grooves in the periphery of the stack, so that a tight connection between the circumference and the wall of the diffuser is ensured.

The circumferential wall also provides a prefixing of the stack because it can hold the entire stack together. Thus, the cost of auxiliary devices can be significantly reduced. The circumferential wall of the diffuser or the collecting box can be pushed so far over the end of the stack of flat heat exchanger tubes that a sufficiently large bonding surface between the wall and the pipe ends is given. Thus, high quality solder joints can be expected.

Each elevation in the wall is a fold, each fold receiving therein a projection which is the edge flange of the heat exchanger tubes consisting of two flat tube halves.

Each recess in the wall is a formed inwardly projecting nose, which fills the groove at the periphery of the stack performing gap between two heat exchanger tubes. However, a furrow should also be understood to mean a shoulder in the circumference of the stack.

As an alternative to the fold, slots may be provided in the wall which are just dimensioned to receive a projection which is the edge flange of the heat exchanger tubes consisting of two flat tube halves.

The ends on the broad sides of the flat heat exchanger tubes abut each other and are connected, wherein the joints (grooves) are the peripheral seams between two heat exchanger tubes.

Alternatively, however, a gap may also be present between the broad sides at the ends of the flat heat exchanger tubes.

In particular, in terms of prefixing is further advantageous if the wall of the diffuser or collecting tank consists of two narrow walls and two wide walls and the wide walls have extensions that extend beyond the ends of end plates, which cover and reinforce the stack of flat heat exchanger tubes. This training is available when the stack height is smaller than the large diameter of the flat heat exchanger tubes, which is useful in a specific application in exhaust gas heat exchangers. Depending on the size of the heat exchanger tubes and the stack height otherwise the extensions could also be arranged on the narrow walls.

The extensions have a step and the end plates have tabs at the ends which are bent after preassembly of the heat exchanger to abut the extensions and hold the heat exchanger together.

A manufacturing advantage is when the diffuser is a manufactured by deep drawing part.

Further features are the subject of the claims.

Particular attention is to be drawn to claims 13 to 15. The claim 13 refers to a heat exchanger, the least in its diffuser on - or Has outlet. A heat exchanger with such a further developed diffuser allows additional simplifications in terms of manufacturability and function. It can also be used with particular advantages where the installation-side restrictions do not permit the attachment of the inlets and outlets for the coolant in the projections of the flat tube halves.

The invention will be described below in an embodiment with reference to the accompanying drawings.

• Fig. 1 Schnitt I - I aus Fig. 3;
• Fig. 2 perspektivische Ansicht des Wärmetauschers mit anzusetzenden Diffusoren;
• Fig. 3 perspektivische Ansicht des Wärmetauschers mit angesetzten Diffusoren;
• Fig. 4 und Fig. 5 Draufsichten auf einen Diffusor;
• Fig. 6 perspektivische Ansicht auf einen Diffusor;

The figures show the following:

• Fig. 1 Cut I - I off Fig. 3 ;
• Fig. 2 perspective view of the heat exchanger with diffusers to be attached;
• Fig. 3 perspective view of the heat exchanger with attached diffusers;
• 4 and FIG. 5 Top views of a diffuser;
• Fig. 6 perspective view of a diffuser;

The Fig. 7 to 15 show a further inventive design of the heat exchanger with a diffuser in several perspective views.

In the exemplary embodiment, a housing-free heat exchanger consisting of a stack of plates is shown, the plates of which, as in FIG EP 0 992 756 A2 is described, deformed and stacked on each other, wherein the plates form flat heat exchanger tubes 2 . For further details of this construction, reference is made to the EP, which should be considered as comprehensively described at this point. It is a cooled by means of coolant exhaust gas heat exchanger, which is involved in a manner not shown in the exhaust gas recirculation system of a motor vehicle. With the same advantages, the heat exchanger is to be used as cooled by means of coolant intercooler.

According to the Fig. 2 and 3 has the exhaust gas heat exchanger the heat exchanger tubes 2, which at the ends have a 4 a diffuser 1 and at the other ends 4 a collecting tank. 1 In Fig. 3 should show the arrows show that the exhaust flows into the top of the exhaust gas heat exchanger through the diffuser 1 and flows out below the header 1 . Coolant flows into the exhaust gas heat exchanger via the inlet connection 20 , which again leaves it via the outlet connection 21 after the heat exchange with the exhaust gas has taken place. On the upper side shown and on the non-visible underside of the exhaust gas heat exchanger, a respective end plate 22 has been arranged, which amplifies the exhaust gas heat exchanger. At the opposite ends of the End plates 22 have been raised on both sides tabs 23 . At the two opposite broad sides of the wall 3 of the diffuser 1 extensions 24 are provided which have a gradation 25 . ( Fig. 6 ) As the Fig. 2 shows the extensions 24 extend beyond the ends of the end plate 22nd The tabs 23 are then bent down onto the extension 24 , so that the stack is pre-fixed for soldering.

In the exemplary embodiments shown, the stack consists only of two heat exchanger tubes 2 . The number of heat exchanger tubes 2 is dependent on the application case and insofar arbitrary. As the Fig. 1 shows, in both heat exchanger tubes 2, an inner insert 26 is arranged to generate turbulence in the exhaust gas and thus to achieve efficient heat exchange. The heat exchanger tubes 2 are made of two flat-tube halves 2a and 2b. The flat-tube halves 2a and 2b have a peripheral flange 12 and are connected together at this edge flange 12th The edge flanges 12 form the projections 9 on the circumference of the stack. Since in this embodiment, the heat exchanger tubes 2 are also connected to each other at their broad sides 15 , also in the periphery of the stack furrows 10 , which are available in the seam area. Their size depends on the bending radius of the flat tube halves 2a , 2b . A smaller bend radius leads to smaller grooves 10 , but smaller bending radii are more difficult to realize. If the grooves 10 are too large, problems arise to solder the wall 3 close to the periphery of the stack. Therefore, 3 recesses 8 (inwardly projecting lugs 13 ) are provided in the wall, which are in the furrows

10 extend into and fill them substantially and thus allow a dense solder joint at these locations. If the flat tube halves 2a , 2b have not, as shown and described, outwardly projecting edge flanges 12 , which represent themselves as projections 9 on the circumference of the stack, but in the pipe interior protruding edge flanges 12 , so lead not shown but well known edge flanges also for the formation of furrows 10 in the periphery of the stack. Such not shown grooves 10 can also be closed by means of a corresponding arrangement of recesses 8 (lugs 13 ) in the wall 3 . In addition, that the legs of a can, in cross section U-shaped flat-tube halves 2a, 2b may be stacked into one another in such a way Flat tube half upwards and the legs of the other flat tube half point down, as for example in the DE 39 04 250 C2 shown and described. In such a type of connection arise at the periphery of the stack paragraphs that are to be regarded as equivalent to the grooves 10 and also by means of corresponding recesses 8 in the wall 3 can be compensated. In addition, elevations 6 are provided in the wall, which are formed as folds 11 . The folds 11 are designed in their dimension so that in each case one of the mentioned projections 9 or one of the outwardly projecting edge flanges 12 fits into a fold 11 and thus also there a dense solder joint is created. The folds 11 can also be designed as slots 7 in the wall 3 , which represent an equivalent solution possibility. The depth of the slots 7 in the wall 3 depends on how far the diffuser 1 is pushed onto the ends 4 of the heat exchanger tubes 2 . In Fig. 1 Bottom 7 was indicated on the bottom right. The slot 7 does not have to be an elevation 6 , as shown, because it could also be present in the undeformed wall 3 and serve its purpose. Of course, slots 7 and folds 11 could also be combined as desired. The slots 7 or elevations 6 or depressions 8 are located in the wall sections of the diffuser 1 , which extend along the two narrow sides of the flat heat exchanger tubes 2 . The broad sides of the diffuser 1 are, just like the broad sides of the flat heat exchanger tubes 2 , flat.

In another embodiment, in a plate heat exchanger between the broad sides 15 of the flat heat exchanger tubes 2, a distance as shown by the reference numeral 27 in the Fig. 2 has been suggested for better understanding. There, the recesses 8 are unnecessary in the wall 3 , because no furrows 10 to be closed are present on the circumference. The mentioned distance 27 corresponds approximately to the height of the flow channels, not shown here, for the cooling liquid, which are also fluidly closed by the deformation of the flat tube halves 2a, 2b, not shown here. This is again on the EP 0 992 756 A2 directed.

The Fig. 7 shows a side view and the Fig. 8 the top view of a further developed heat exchanger. This heat exchanger also has a diffuser 1 , in which the wall 3 extends circumferentially around the entire circumference of the end of the stack and has elevations 6 , which with projections 9 on Circumference of the stack correspond to ensure a tight connection between the periphery and the wall 3 , wherein the wall 3 has at least one inlet 20 or outlet 21 for the other medium, which flows between the heat exchanger tubes 2 has.

The wall 3 can - but not necessarily - also have depressions 8 , which correspond to grooves 10 at the periphery of the stack. This will depend on how sharp-edged the flat tube halves 2a , 2b are formed and whether the grooves 10 formed are so large that they have to be filled with the recesses 8 in order to perform a quality soldering process can. The wall 3 has a peripheral extension 30 in which the inlet 20 or the outlet 21 is arranged. The two flat tube halves 2a , 2b forming the heat exchanger tubes 2 are deformed in the region of the circumferential extension 30 such that a hydraulic connection is created between the peripheral extension 30 and the flow channels 40 arranged between the heat exchanger tubes 2 for the other medium. This other medium is the coolant. The inlet 20 or the outlet 21 can be arranged at any point of the circumference in the peripheral extension 30 , whereby in this regard constructive freedoms arise, which must be attributed to the invention. In the embodiments shown, the inlet 20 or the outlet 21 has a round cross section and a drawn edge 80 (FIG. Fig. 9 ) around the opening, in order to be able to apply a suitable nozzle there. Other designs have an approximately rectangular cross-sectional shape. The present invention should also be understood as meaning that the heat exchanger can be flowed through in a U-shape, wherein the inlet 20 and the outlet 21 are located on one and the same diffuser 1 .

In the embodiments shown, the recesses 8 already mentioned are provided only on one side of the circumferential extension 30 , on the side facing the inlet or outlet for the exhaust gas. Regarding the opposite side is from the Fig. 10 to recognize that it has provided by a locally sharp-edged training 50 to the flat tube halves 2a , 2b for a very small groove 10 , whereby a recess 8 on this side of the peripheral extension 30 is unnecessary. The sharp-edged formation 50 also allows the bending edges designated 70 in the wall 3 of the diffuser 1 to the required quality with the outer edges of the stack of heat exchanger tubes 2 are soldering. In these edges 70 are often the problem areas from the perspective of soldering.

The elevations 6 in the wall 3 are interrupted in the region of the peripheral extension 30 . What is meant by this is clear from the Fig. 7 but also from the Fig. 9 and 11 - 13 to recognize where the ridges 6 are provided on the left and right of the peripheral extension 30 to each receive the projection 9 formed by the edge flange 11 of the two flat tube halves 2a , 2b . To enter is in particular again on the Fig. 10 because this refinement of the diffuser 1 requires or permits a different configuration of the flat tube halves 2a , 2b from this FIG. 10 can be seen, which offers a view into the interior of the heat exchanger, because there - in contrast to Fig. 9 - The diffuser 1 has been omitted. The Fig. 10 shows that the two flat tube halves 2a , 2b in the end region, which is encompassed by the wall 3 of the diffuser 1 , are reshaped so that a hydraulic connection to the flow channels 40 between the heat exchanger tubes 2 is achieved. The flow channels 40 have been realized by the special deformation of the flat tube halves 2a , 2b , as well as from the Fig. 14 can be seen, which shows a section in the longitudinal direction of the heat exchanger in the region of the diffuser 1 . A relatively wide transverse bead 60 in the flat tube halves provides excellent solder joints, both between the inside of the wall 3 of the diffuser 1 and between the individual flat tube halves 2a and 2b . The remaining figures speak for themselves, which is why further explanations seem to be dispensable. The Fig. 11 - 13 show the diffuser 1 as an item from different angles. The Fig. 15 , which also shows a longitudinal section through the heat exchanger in the region of the diffuser 1 , differs from the Fig. 14 in that only a single heat exchanger tube 2 has been drawn, as a result of which other details are better visible. The number of heat exchanger tubes 2 depends on the application, as already mentioned in the introduction. Restrictions are not recognizable and if they are, they are not intended.

Claims (15)

1. Heat exchanger having a diffuser (1) for the introduction of a medium into flat heat exchanger tubes (2), wherein the diffuser (1) has a wall (3) that extends along the ends (4) of a stack of flat heat exchanger tubes (2), and the inner side (5) of the wall (3) is sealingly connected to the ends (4) by means of brazing, wherein the wall (3) extends in an encircling manner around the entire circumference of the end of the stack,
   characterized in that
   the wall (3) has depressions (8), wherein the depressions (8) correspond to furrows (10) in the circumference of the stack,
   and/or in that the wall (3) has slots (7) and/or elevations (6), wherein the elevations (6) and/or slots (7) correspond to projections (9) on the circumference of the stack in order to ensure a sealed connection between the circumference and the wall (3).
2. Heat exchanger according to Claim 1, characterized in that the wall (3) has elevations (6), wherein each elevation (6) in the wall (3) is a fold (11), wherein each fold (11) receives within it a projection (9) which is the edge flange (12) of the heat exchanger tubes (2) composed of two flat tube halves (2a, 2b).
3. Heat exchanger according to Claim 1, characterized in that the wall (3) has depressions (8), wherein each depression (8) in the wall (3) is an inwardly projecting lug (13) produced by deformation techniques, which lug fills out the joint, which constitutes a furrow (10) on the circumference of the stack, between two heat exchanger tubes (2).
4. Heat exchanger according to Claim 1, characterized in that the wall (3) has slots (14), wherein each slot (14) in the wall (3) is dimensioned precisely so as to receive a projection (9) which is the edge flange (12) of the heat exchanger tubes (2) composed of two flat tube halves (2a, 2b).
5. Heat exchanger according to Claims 1 to 4, characterized in that the ends (4) at the wide sides (15) of the flat heat exchanger tubes (2) bear against, and are intended for connection to, one another, wherein the furrows (10) are the edge-side seams between two heat exchanger tubes (2).
6. Heat exchanger according to the preceding claims, characterized in that the elevations (6) and/or depressions (8) and/or slots (7) are arranged in those wall portions of the wall (3) which extend along the narrow sides of the flat heat exchanger tubes (2).
7. Heat exchanger according to one of the preceding claims, characterized in that a spacing (27) is present between the wide sides (15) at the ends (4) of the flat heat exchanger tubes (2).
8. Heat exchanger according to one of the preceding claims, characterized in that the wall (3) of the diffuser (1) has two narrow walls and two wide walls, and in that, preferably, the wide walls have elongations (24) which extend beyond the ends of closure plates (22) which cover and reinforce the stack of flat heat exchanger tubes (2).
9. Heat exchanger according to Claim 8, characterized in that the elongations (24) have a step (25).
10. Heat exchanger according to Claims 8 and 9, characterized in that the closure plates (22) have tabs (23) on the ends, which tabs, after the preliminary assembly of the heat exchanger, are bent so as to bear against the elongations (24).
11. Heat exchanger according to the preceding claims, characterized in that the diffuser (1) is a part produced by deep drawing.
12. Heat exchanger according to one of the preceding claims, characterized in that it is used as a liquid-cooled exhaust-gas heat exchanger in exhaust-gas recirculation systems of motor vehicles, or as a charge-air cooler.
13. Heat exchanger according to Claim 1, characterized in that the wall (3) has at least one inlet (20) and/or one outlet (21) for the other medium that flows between the heat exchanger tubes (2).
14. Heat exchanger according to Claim 13, characterized in that the wall (3) has a circumferentially expanded portion (30) in which the inlet (20) and/or the outlet (21) are/is arranged, and in that the two flat tube halves (2a, 2b) which form in each case one heat exchanger tube (2) are, in the region covered by the circumferentially expanded portion (30), deformed such that a hydraulic connection is produced between the circumferentially expanded portion (30) and the flow ducts (27, 40), arranged between the heat exchanger tubes (2), for the other medium.
15. Heat exchanger according to Claims 13 and 14, characterized in that the elevations (6) and/or slots (7) in the wall (3) are interrupted in the region of the circumferentially expanded portion (30).

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