WO2004102103A2

WO2004102103A2 - Heat exchanger which is intended, in particular, for a motor vehicle

Info

Publication number: WO2004102103A2
Application number: PCT/FR2004/001179
Authority: WO
Inventors: Christian Mahe; Daniel Frasca; Gérard Gille
Original assignee: Valeo Thermique Moteur
Priority date: 2003-05-15
Filing date: 2004-05-14
Publication date: 2004-11-25
Also published as: FR2856783B1; FR2856783A1; EP1623177A2; WO2004102103A3

Abstract

The invention relates to a heat exchanger which is intended, in particular, for motor vehicles. The inventive heat exchanger comprises: a bundle of fluid-circulation tubes (2); at least one manifold (3, 4), the two ends of each of the aforementioned tubes being inserted in receiving holes (6) which are provided in said manifold(s) using a fluid-tight connection; and means (10) for promoting the exchange of heat between a flow of air passing through the exchanger and the fluid circulating in the tubes (2). According to the invention, the connection between the ends of the tubes and the manifold(s) (3, 4) comprises a braze joint and, once the tubes and the manifold(s) (3, 4) have been brazed, the heat exchange-promoting means (10) can be mechanically assembled to said tubes.

Description

Heat exchanger, in particular, for cars.

The invention relates to a heat exchanger, a heat exchange module comprising such a heat exchanger as well as a method for producing such a heat exchanger and such a heat exchange module. It will find its applications, in particular, in the automotive field.

In this field, the exchangers generally consist of a row of tubes, inside which a fluid circulates, fins, cooperating with said tubes to promote the exchange of heat between said fluid and a flow of air passing through. said fins, and manifolds, the ends of each tube engaging in a fluid tight connection in the receiving holes provided in the manifolds. The tubes, the fins and at least part of the manifolds are most often made of aluminum and / or aluminum alloy.

According to a first technology, the fins are flat and arranged perpendicular to the tubes. They are provided with cutouts in which the tubes are introduced. The assembly between the tubes and the fins is of the "mechanical" type, that is to say, obtained by clamping, in particular by radial expansion of the tubes in said cutouts, provided with closed contour, and / or by insertion of the tubes in said cutouts, provided with an open outline, with deformation of the fins.

The seal at the connection between the tubes and the collectors is obtained by radial clamping of the tubes in collars formed on the collectors around the holes. This technique requires a radial expansion of the tubes in line with the collars or a constriction thereof. The use of a plastic seal at the collars is also most often necessary to seal the connection between the tubes and the manifold.

According to another technology, the tubes are fixed to the manifolds by brazing, which makes it possible to promote the sealing of the connection. However, in this case, the fins are also brazed on the tubes. For this, the tubes, on the one hand, and / or the manifolds and the fins on the other hand, must be coated with a layer of plating allowing brazing. This solution also requires the use of a flux which must be applied to the whole of the exchanger to promote the diffusion of the plating layer during brazing.

The object of the invention is to remedy these drawbacks

The invention thus relates, first of all, to a heat exchanger comprising a bundle of fluid circulation tubes, at least one collecting element, the two ends of each tube engaging in a fluid tight connection in holes. reception provided in the collecting element (s), and means for promoting the heat exchange between an air flow passing through the exchanger and the fluid circulating in the tubes, characterized in that the connection between the ends of the tubes and the collector (s) is constituted by a brazing joint and the means for promoting heat exchange are able to be assembled mechanically on the tubes after brazing the latter and the collector elements.

We thus have a solution according to which the tightness between the tubes and the collectors is optimized because the connection used is of metallographic type, and according to which it is not necessary to use plated material to ensure the fixing of the tubes and means for promoting heat exchange. Since the soldering is also located at the joint between the tubes and the collectors, it suffices to apply flux only at the longitudinal ends of the tubes.

In other words, the tubes of the exchanger according to the invention and the fins may be free of any solder plating layer and the solder present at the level of the tubes will be located at the level of the tube-manifold junction. In addition, by using means to promote the exchange, such as fins, capable of being fixed to the tubes after brazing said tubes on the manifolds, it is avoided that said means for promoting exchange are damaged by brazing.

According to an advantageous embodiment, said means for promoting heat exchange consist of a block of fins provided with open contour cutouts for lateral reception of the tubes, said tubes being able to be inserted into said cutouts with deformation of the fins. It is thus possible to assemble the fins on the tubes after brazing the tubes and the collectors.

Other optional, complementary or alternative characteristics of the invention are set out below:

- The collecting element or elements are provided at least in part with a plating layer for the production of said brazing joint.

- At least one collecting element is a fluid box or collecting box defining at least one chamber ^' for collecting the fluid in communication with the tubes.

- At least one fluid box comprises a hollow part and a collecting plate closing the latter in a fluid-tight manner and presenting the receiving holes.

- At least one collecting element is a collecting plate having the receiving holes and suitable for covering a hollow part in a fluid-tight manner to form a fluid box.

- The fins are formed by a multiplicity of substantially flat and parallel plates.

- The planes of the fins are substantially perpendicular to the longitudinal direction of the tubes. - Said cutouts are notches formed from the edge of the fins facing the tubes.

- The fins are constituted by a corrugated plate having ripple ridges turned towards the tubes and which extend parallel to said alignment direction, each of said cutouts overlapping one of the ripple ridges.

The edges, cutouts are folded to form collars along the tubes.

It should be noted that these latter two embodiments are also advantageous when they are applied to the exchangers of the state of the art as mentioned in the introduction.

The invention may also relate to a heat exchange module comprising a first heat exchanger as mentioned above and a second heat exchanger, module in which said block of fins is common to said first heat exchanger and to said second heat changer, said second heat exchanger comprising fluid circulation tubes which pass through openings in the fins. Thus, the exchangers of the module according to the invention are traversed by the same air flow.

The invention also relates to a method for producing a heat exchanger, in particular an exchanger as mentioned above, method in which there are fluid circulation tubes in at least one bundle, at least one or more collecting elements are provided , the two ends of each tube are engaged in receiving holes provided in the collecting element or elements, a brazing joint is produced between said tubes and at least one of said collecting elements and these tubes are mechanically assembled and means for promote heat exchange between the fluid circulating in the tubes and an air flow crossing the exchanger.

According to advantageous embodiments:

^" - said means for promoting heat exchange being made up of a block of fins having open contour cutouts in the direction of the tubes for receiving them, provided arranged in a row, said tubes are assembled beforehand said collector (s) and then one moves towards the other, in a direction perpendicular to the longitudinal direction of the tubes and to the direction of alignment of the row (s), the assembly thus obtained so as to introduce laterally the tubes in said cuts,

- the tubes and the collecting element (s) are brazed by induction.

The invention further relates to a method of assembling a module as mentioned above, method in which said first heat exchanger is produced according to the method for producing an exchanger mentioned previously while the tubes of the second exchanger are .already assembled with the fin block and at least one fluid box or manifold box of said second exchanger.

The characteristics and advantages of the invention will be explained in more detail in the description below, with reference to the accompanying drawings.

Figures 1 is a perspective view illustrating an example of a heat exchanger according to the invention.

FIG. 2 is a partial sectional view of the exchanger of FIG. 1, the section being made according to a section plane orthogonal to the row of tubes of the exchanger, near one of the collecting elements of said exchanger, said view serving to illustrate, at one of the tubes, the connection between the latter and said collector. FIG. 3 is a partial side view of a fin of the exchanger of FIG. 1.

Figure 4 "is a perspective view of a variant fin.

Figures 5 and 6 are perspective views illustrating successive phases of the method according to the invention.

Figure 7 is a perspective view of a heat exchanger module according to the invention.

FIG. 8 is a partial sectional view showing some tubes and a fin of the exchanger of FIG. 7.

FIG. 9 is a partial perspective view illustrating a step in the method according to the invention for producing the exchanger of FIG. 7.

As illustrated in FIG. 1, the invention relates to a heat exchanger 1 comprising an assembly formed by a bundle of tubes 2 and collecting elements 3, 4, the two ends of each tube engaging respectively in holes 6 provided in the collecting elements 3, 4.

Said bundle consists, for example, of a row of tubes 2 and said holes 6 of the collecting elements are located one below the other.

According to the invention, the connection between the ends of the tubes and the collecting element or elements consists of a brazing joint 7, illustrated in FIG. 2.

Said tubes 2 are, for example, rectilinear and / or flat, that is to say, provided with two substantially planar faces 16, 17, mutually parallel. Said tubes 2 are, in particular, made of aluminum and / or aluminum alloy. According to the illustrated embodiment, the collecting elements 3, 4 consist of a collecting plate 18, provided with said holes 6 for introducing the tubes, and a complementary cover 15 to define a volume in communication with the tubes 2. The collector plate is made of aluminum and / or aluminum alloy and carries said plating while the cover 15 is plastic. The latter may also be made of aluminum and / or aluminum alloy. It will then also be provided with a plating layer for soldering with the collector plate. This latter scenario can also be encountered in the case of a collector consisting of two half-shells defining a tubular element plugged at its two longitudinal ends, one of the half-shells forming a collector plate and the other cover.

According to another embodiment, said collecting elements may consist of a tubular element, formed in one piece and plugged at its two longitudinal ends, said tubular element being provided laterally with said holes for introducing the tubes. This tubular element is made of aluminum and / or aluminum alloy and carries the said plating layer for brazing.

Said collecting elements are provided with inlet and / or outlet openings for the fluid.

Referring again to FIG. 1, it can be seen that the exchanger according to the invention also comprises means 10 for promoting the exchange of heat between an air flow passing through the exchanger and the circulating fluid. in the tubes 2.

It is, for example, a block composed of a multiplicity of fins 8 in the form of metal sheets, each of which extends substantially along a plane perpendicular to the longitudinal direction of the tubes, and which are mutually juxtaposed in this direction. The block of fins 8 has the shape of a rectangular parallelepiped having two faces main parallels to the longitudinal direction of the tubes and to the longitudinal direction of the header plates 18.

According to the invention, said means 10 for promoting heat exchange are able to be assembled mechanically on the tubes after brazing them in the manifolds 3,4.

To ensure the connection between the tubes 2 and the manifold elements 3,4, there is provided a plating layer for the production of said brazing joint 7, for example, at the level of said manifold elements 3,4. It is then no longer necessary to provide such a plating layer either on the tubes 2 or on the means for promoting exchange 10.

As can be seen from FIG. 3, the fins 8 constituting said means for promoting heat exchange according to the illustrated embodiment are provided with cutouts 13 of open outline for the lateral reception of the tubes 2, said tubes 2 being able to be introduced into said cutouts 13 with deformation of said fins.

According to this embodiment, each fin has a multiplicity of cutouts 13 superimposed and oriented in a direction perpendicular to its longitudinal direction, which corresponds to the longitudinal direction of the collector plates, namely a cut facing each tube 2. Said cutouts are open from one of the longitudinal edges 23 of the fin. They have edges 24 parallel in pairs, capable of matching the flat faces of the tubes.

In a manner known to those skilled in the art, said fins 8 may be provided with louvers 26, intended to disturb the flow of the air flow passing through them.

The fin block 8 is spaced from said manifolds 3,4, more precisely from said manifold plates 15, by a distance varying, for example, from 0.1 to 1 cm. Said distance is, in particular, less than 0.8 cm. It can advantageously be between 0.3 and 0.5 cm.

FIG. 4 relates to a variant of the heat exchanger according to the invention, in which the individual fins are replaced by a single metal sheet 20 folded in a zigzag. The sheet 20 is thus formed of a multiplicity of substantially planar flaps 21 each extending from a transverse fold 22 to another transverse fold 23, the folds 22 on the one hand and the folds 23 on the other hand being located in two planes spaced from each other, both parallel to the longitudinal direction of the tubes 2 and to the longitudinal direction of the manifolds not shown. To receive the tubes, the sheet 20 has cutouts 24 in the form of elongated slots perpendicular to the folds 22, 23. Each slot 24 passes through one of the folds 23 and extends, on either side thereof, up to the vicinity of the two neighboring folds 22. The cuts formed by the slots 24 in the generally parallelepiped block resulting from the folding of the sheet 20 are thus open on the side of the folds 23, allowing the introduction of the tubes 2 by a movement of the latter perpendicular to the planes containing the folds .

We see in Figure 4 that the sheet 20 has, as known per se, along the longitudinal edges of the slots 24, collars 25 folded so as to be applied on the flat faces of the tubes and thus improving the thermal contact between the tubes and the block. Such collars are advantageously also provided on the fins of FIGS. 1 and 3. Louvers 26 are also provided, as known per se, in the flaps 21 of the sheet 20.

It can also be seen in FIG. 4 that the tubes 2 extend beyond the tubes 23 and are therefore not in contact with the sheet 20 over the entire width of their planar lateral faces. As a variant, the tubes may be entirely between the plane of the folds 22 and that of the folds 23, thus increasing the exchange surface between the tubes and the fin block.

According to the illustrated embodiment, said exchanger constitutes a radiator for cooling a motor vehicle engine. It may however be any other type of exchanger, such as a condenser. Such use is illustrated in Figures 7 to 9, in the particular context of a module.

As illustrated in FIGS. 5 and 6, the exchanger described in FIG. 1 was obtained, according to the method according to the invention, for example, by aligning the tubes 2 in a row, and by moving the collector plates 18 relative to to these, according to arrows F3 and F4 to introduce their ends 5 into the holes 6 of the collectors. The tubes 2 and the collector plates 18 are then brazed at the level of the said orifices 6 to form a set of tubes and collectors.

It also forms the fin block 8. It is thus possible, by moving the assembly of tubes and manifolds already obtained towards the fin block 8, according to arrow FI, to introduce the tubes into the cutouts 13, to obtain the configuration shown in Figure 6 in which the tubes and the fins are mechanically assembled.

It only remains, to obtain the complete heat exchanger shown in FIG. 1, to fix on the collecting plates 18, in a manner known per se, the complementary hollow parts 15 to form fluid boxes therewith. each delimiting at least one compartment in fluid communication with the tubes so as to define the manifolds 3,4.

In general, the ends 5 of the tubes and / or the collector plates 3, 4, may be coated locally, before brazing, with a flux allowing the realization of the connection to be promoted. Brazing can be carried out with a flame. It can also be carried out by induction. For this, the tube and manifold assemblies are circulated in two inductors, arranged on each side of said assemblies, said inductors being supplied with electric current. Said inductors have a C shape and are placed head to tail, the collectors circulating between the horizontal branches of said inductors. Depending on the air gap existing between said branches and the collectors and the thickness of the material to be brazed, the intensity of the electric current flowing in the inductors is regulated to allow the desired temperature to be obtained at the orifices 6 of the manifolds and the end of the tubes 2.

As illustrated in FIGS. 7 to 9, the invention also relates to a heat exchanger module comprising a fin block 30 common to a first exchanger, for example a radiator for cooling the drive motor of a vehicle, and to a second heat exchanger, for example a condenser belonging to a vehicle air conditioning loop. In addition to the fin block 30, the radiator 40 comprises, for example, a row of flat tubes 41 (FIG. 8) and two fluid boxes each formed by a collecting plate, crossed by the ends of the tubes, and by a hollow part 41 assembled in a fluid-tight manner at the periphery of the collector plate. The condenser 50 comprises a row of tubes 51 and two tubular manifolds 52 having openings for the passage of the ends of the tubes. Each manifold 52 extends along one of the fluid boxes 42, side by side with it, the rows of tubes 41 and 51 also extending side by side and the tubes being parallel to each other. As in the case of FIGS. 1 to 3, the block of fins 30 is formed from a multiplicity of metal sheets 31 extending substantially in parallel planes.

According to the invention, the condenser is. an exchanger such as described above in which the connection between the tubes 51 and the collectors 52 consists of a brazing joint. In addition, the tubes 51 of the condenser engage in cutouts 34 formed in the fins 31, in the form of notches which open into one 53 of the longitudinal sides of the fin, while the tubes 41 of the radiator pass through holes 35, in particular of closed contour, aligned along the opposite edge 36 of the fin.

To obtain such a module, after assembling the block 30, the tubes 41 and the fluid boxes 42, by suitable means which are not part of the invention, and having assembled the tubes 51 and the boxes on the other hand manifolds 52, according to the process already mentioned, the two assemblies obtained are arranged as shown in FIG. 9, the tubes 51 being opposite the notches 33. The assembly 51-52 is then moved towards the assembly 30-41-42 , according to arrow F5 in FIG. 8, to introduce the tubes 51 into the notches 33.

Claims

1. Heat exchanger comprising a bundle of fluid circulation tubes (2), at least one collecting element

(3, 4), the two ends (5) of each tube engaging in a fluid-tight connection in receiving holes (6) provided in the collecting element or elements, and means (10) for promoting the heat exchange between an air flow passing through the exchanger and the fluid circulating in the tubes, characterized in that the connection between the ends of the tubes and the collecting element or elements consists of a brazing joint (7) and said means (10) for promoting heat exchange are capable of being mechanically assembled on the tubes after brazing them and the collecting elements.

2. Exchanger according to claim 1 wherein said means (10) for promoting heat exchange consist of a block of fins. (8) provided with cutouts (13) of open outline for the lateral reception of the tubes (2 ), said tubes (2) being able to be inserted into said cutouts (13) with deformation of the fins.

3. Exchanger according to claim 2 wherein the distance between said block of fins (8) and the collectors (3, 4) is between 0.1 and 1 cm.

4. Exchanger according to any one of the preceding claims, in which the collecting element or elements (3,4) are provided at least in part with a plating layer for the production of said brazing joint (7).

5. Exchanger according to any one of the preceding claims, in which at least one collecting element is a fluid box or collecting box (52) defining at least one fluid collecting chamber in communication with the tubes.

6. Exchanger according to any one of the preceding claims, in which at least one fluid box comprises a hollow part and a collecting plate closing the latter in a fluid-tight manner and presenting the receiving holes.

7. Exchanger according to any one of the preceding claims, in which at least one collecting element is a collecting plate (18) having the receiving holes (6) and suitable for covering a hollow part (15) in a fluid-tight manner for form a fluid box.

8. Exchanger according to claim 2, wherein the fins are constituted by a multiplicity of plates (31) substantially planar and parallel.

9. Exchanger according to claim 2, wherein the planes of the fins are substantially perpendicular to the longitudinal direction of the tubes.

10. Exchanger according to claim 2, wherein said cutouts are notches (13,34) formed from the edge (23,53) of the fins facing the tubes.

11. Exchanger according to claim 2, wherein the fins consist of a corrugated plate (20) having corrugation ridges (23) facing the tubes and which extend parallel to said alignment direction, each of said cutouts (24) overlapping one of the corrugation ridges.

12. Exchanger according to one of claims 2 to 10, wherein the edges of the cutouts are folded back to form collars (25) along the tubes.

13. Heat exchange module comprising a first heat exchanger according to any one of the preceding claims and a second heat exchanger, module in which said block of fins (30) is common to said first heat exchanger (50) and to said second heat exchanger (40), said second heat exchanger comprising fluid circulation tubes (41) which pass through openings (35) formed in the fins (31) .

14. Method for producing a heat exchanger in which there are tubes (2) for circulating fluid in at least one bundle, at least one or more collecting elements (3,4) are provided, the two ends (5) are engaged ) of each tube in receiving holes (6) provided in the collecting element or elements, a brazing joint is produced between said tubes and at least one of said collecting elements (3, 4) and said tubes are assembled mechanically and means for promoting the exchange of heat between the fluid circulating in the tubes and an air flow passing through the exchanger.

15. The method of claim 14 wherein, said means for promoting heat exchange consisting of a block of fins (10) having cutouts (13) of open outline in the direction of the tubes for receiving them- ci, provided arranged in a row, said tubes and said collector (s) are assembled beforehand and then they are moved towards one another, in a direction (FI) perpendicular to the longitudinal direction of the tubes and to the direction of alignment of the row or rows, the assembly thus obtained so as to introduce the tubes laterally into said cutouts.

16. Method according to one of claims 14 or 15, wherein the tubes and the collecting element or elements are induction brazed.

17. A method of assembling a module according to claim 13 in which said first heat exchanger is produced according to the method according to claim 14 while the tubes (41) of the second exchanger are already assembled to the fin block and at least one box fluid or manifold (42) of said second exchanger.