EP1192402B1 - Multichannel tube heat exchanger, in particular for motor vehicle - Google Patents

Description

The invention relates to heat exchangers, in especially for motor vehicles.

It relates more particularly to a heat exchanger suitable for constituting either a radiator for cooling the engine, either a radiator for heating the passenger compartment, or still an evaporator or a condenser of a circuit of air conditioner.

Generally, a heat exchanger of this type includes a bundle of tubes mounted between two fluid boxes by through respective collectors, and is specific to be traversed by a fluid. A heat exchanger of this type is described in German Patent Application DE 197 19 259.

In the case of an engine cooling radiator or a radiator for heating the passenger compartment, this fluid is the liquid used to cool the engine. In the case an air conditioning evaporator or condenser, this fluid is a refrigerant.

Generally, the fluid is distributed between the tubes of the beam by successive passes in different groups of tubes and in respective directions of flow.

Usually the bundle includes either flat tubes associated with corrugated dividers, i.e. tubes of circular or oval section crossing a series fins. In this case, the change of password is obtained thanks to transverse and longitudinal partitions located inside the fluid boxes provided at both ends of the tube bundle.

These partitions are either attached and brazed between the box fluid and the corresponding manifold, either obtained by stamping of the fluid box to define compartments who communicate respectively with groups of beam tubes.

In this known technique, the collector comprises openings, also called slots, fitted with collars linkage into which are inserted and brazed the ends of the tubes.

This results in the need for the longitudinal partitions fluid boxes are notched to fit perfectly with the shapes of the collector.

Thus, in the prior art, the question always arises problem of obtaining a perfect seal between the collector, the longitudinal partition of the fluid box and the tubes.

The object of the invention is in particular to overcome the drawbacks supra.

To this end, it offers a heat exchanger of the type defined in the introduction, in which the tubes include each several channels separated by at least one partition longitudinal and are arranged in a single row, parallel to two large faces of the exchanger. In this heat exchanger, fluid circulation takes place in at least two layers parallel to the large faces of the exchanger and each formed from part of the channels of the tubes, and at least one of the fluid boxes includes a internal longitudinal partition suitable for dividing the box fluid in at least two communicating longitudinal compartments respectively with the two tablecloths.

Thus, the heat exchanger of the invention comprises tubes each having several channels, the respective channels of each tube being each time divided into at least two groups corresponding to traffic slicks.

In the particular case of an exchanger with two layers of traffic, each located near one of the large faces of the heat exchanger, each tube is divided into two groups, a first group which corresponds to a first tablecloth and a second group which corresponds to a second tablecloth.

These two layers thus communicate respectively with the two longitudinal compartments defined in at least one of the two fluid boxes.

A tube according to the invention has at least two channels which then correspond respectively with the two compartments aforementioned longitudinal. In case each tube has more than two channels, the numbers of channels in the first group and in the second group can be equal or different.

According to another characteristic of the invention, one at less fluid boxes includes at least one partition transverse suitable for dividing the fluid box into at least two transverse compartments of which at least one establishes communication between two layers.

According to yet another characteristic of the invention, each tablecloth is divided into at least two sub-tablecloths connected in series and in which the circulation of the fluid takes place against the current from one sublayer to the next.

Thus, in a typical embodiment, the heat exchanger heat includes two layers, each divided into two sub-layers, which makes it possible to define a circulation with four passes: two successive passes in the two sub-layers of a first layer, and then two successive passes in the two sub-layers of a second layer.

According to the invention, each collector has openings, also called slots, surrounded by collars for the introduction of the ends of the beam tubes and each collector is expected to be provided with a flat surface for soldering a can fluid.

This characteristic is particularly advantageous because it allows to oppose a perfectly flat surface for position the longitudinal partition and / or the partition transverse of the fluid box.

It is provided for this that each fluid box includes a plan periphery and at least one coplanar partition (partition longitudinal and / or transverse bulkhead) suitable for brazed against the collector surface.

It is possible to realize the flat surface of a single piece with the collector.

However, in a preferred embodiment of the invention, the flat surface of each collector is part of a collector plate attached by brazing to the collector and having openings aligned with the openings of the manifold.

This enables a flat reference surface to be produced. from a plate comprising openings, advantageously obtained by punching.

The heat exchanger of the invention can comprise at least minus one leg from one edge of the manifold or plate manifold, or fluid box, said tab being folded respectively over one edge of the fluid box, or on an edge of the collector or the collector plate.

According to another characteristic of the invention, the end at least one longitudinal partition of the tube is positioned substantially at the level of the flat surface of the collector, so that this longitudinal wall of the tube can be brazed to an internal longitudinal partition of the fluid box.

The fluid boxes are advantageously each formed by stamping of a metal plate to define the perimeter plan and the coplanar partition.

So when a fluid box is brazed against the surface corresponding plane, the periphery of the fluid box and the or the partition (s) of it come to be brazed closely against the flat surface, which makes it possible to delimit compartments communicating with tubes appropriately to define a circulation in several passes.

According to another advantageous characteristic of the invention, at least one of the fluid boxes comprises at least one fluid inlet or outlet tubing.

The tubes of the heat exchanger of the invention are susceptible of numerous variants. So we can provide, for example, that each tube is a tube extruded, or that each tube is formed from a sheet folded and closed by longitudinal brazed joints, or still that each tube is formed of two sheet metal plates stamped parts which are tightly brazed.

According to yet another advantageous characteristic of the invention, the channels of the tubes are separated by partitions whose respective thicknesses have decreased since a central region of the tube towards the periphery.

In a preferred application of the invention, the exchanger of heat constitutes an evaporator for a air conditioner.

• la figure 1 est une vue partielle en perspective et en coupe d'une partie d'un échangeur de chaleur selon l'invention, la vue faisant apparaítre le collecteur, la plaque collectrice et l'un des tubes du faisceau ;
• la figure 2 est une vue partielle en perspective d'une boíte à fluide propre à être brasée sur la plaque collectrice de l'échangeur de chaleur de la figure 1 ;
• la figure 3 est une vue partielle en coupe d'une boíte à fluide brasée sur une plaque collectrice d'un échangeur de chaleur selon l'invention ;
• la figure 4 est une vue partielle en perspective éclatée d'un échangeur de chaleur selon l'invention ;
• la figure 5 est un schéma montrant la circulation du fluide dans l'échangeur de chaleur de la figure 4 ;
• la figure 6 est une vue en coupe transversale d'un tube selon l'invention formé par extrusion ;
• la figure 7 est une vue en coupe transversale d'un tube selon l'invention formé à partir d'une tôle ;
• la figure 8 est une vue en coupe transversale d'un tube selon l'invention formé à partir de deux tôles ;
• la figure 9 est une vue partielle en perspective d'un échangeur de chaleur selon une autre forme de réalisation de l'invention ; et
• la figure 10 est une vue en perspective d'une des boítes à fluide de l'échangeur de chaleur de la figure 9.

In the description which follows, given solely by way of example, reference is made to the appended drawings, in which:

• Figure 1 is a partial perspective view in section of part of a heat exchanger according to the invention, the view showing the manifold, the collector plate and one of the bundle tubes;
• Figure 2 is a partial perspective view of a fluid box suitable for being brazed on the header plate of the heat exchanger of Figure 1;
• Figure 3 is a partial sectional view of a fluid box brazed to a header plate of a heat exchanger according to the invention;
• Figure 4 is a partial exploded perspective view of a heat exchanger according to the invention;
• Figure 5 is a diagram showing the circulation of the fluid in the heat exchanger of Figure 4;
• Figure 6 is a cross-sectional view of a tube according to the invention formed by extrusion;
• Figure 7 is a cross-sectional view of a tube according to the invention formed from a sheet;
• Figure 8 is a cross-sectional view of a tube according to the invention formed from two sheets;
• Figure 9 is a partial perspective view of a heat exchanger according to another embodiment of the invention; and
• FIG. 10 is a perspective view of one of the fluid boxes of the heat exchanger of FIG. 9.

We first refer to Figure 1 which shows part of a heat exchanger comprising a bundle having a multiplicity of tubes 10, only one of which is shown on the Figure 1. These are flat tubes, arranged in a single row, and made by extruding a material metallic, preferably based on aluminum. These tubes have a plurality of parallel internal channels 12 which are seven in the example and are separated by longitudinal partitions 78. The row of tubes is parallel to two large opposite faces F1 and F2 of the exchanger heat.

The tubes 10 are spaced apart to delimit, between two adjacent tubes, an interval which can be free or occupied by a corrugated interlayer (not shown) forming heat exchange surface.

The tubes 10 have respective ends 14 received in a collector 16 consisting of a stamped metal plate of generally rectangular shape with two longitudinal sides corresponding respectively to the large faces F1 and F2 of the heat exchanger. The end 14 of each tube 10 defines a flat face that extends perpendicular to the longitudinal direction of the tube and which also constitutes the end of each longitudinal partition 78

The collector 16 has a plurality of openings 18, also called slots, having an internal section adapted to the external section of a tube. Each of the openings 18 is bordered by a collar 20 so that the openings 18 can receive respectively the ends 14 of the tubes 10 of the beam. The ends 14 of the tubes are provided for be brazed with the respective collars 20 to ensure a waterproof connection.

The collector 16 receives a collecting plate 22 of form rectangular advantageously made of a base material aluminum. This collector plate 22 is designed to be soldered to the collector 16 and to provide a surface plane 24, forming a reference surface, and it comprises a multiple openings 26, also called slots, arranged opposite the respective openings 18 of the collector 16.

These openings 26 have a shape adapted to that of the ends 14 tubes for them to engage, at least in part, in the openings 26, without however exceeding plane defined by the planar surface 24. In fact, the end 14 of each tube is positioned so that it is located substantially at the level of the flat surface 24.

The flat surface 24 is designed to receive a box for fluid 28, as shown in FIG. 2, which is produced by stamping a metal sheet, advantageously at aluminum base.

The fluid box 28 of Figure 2 includes a periphery device 30 of generally rectangular shape which is planar and clean to come into contact with the perimeter of the surface plane 24. For this purpose, the periphery 30 has a shape general rectangular adapted to the rectangular shape of the flat surface 24. In the example shown in Figure 2, this the periphery comprises in particular two longitudinal edges 32.

In addition, the fluid box 28 includes a longitudinal partition 34 which extends parallel to the edges 32 and a transverse partition 36 which extends perpendicular to the partition 34 and edges 32. The periphery 30 and the partitions 34 and 36 are coplanar.

The fluid box 28 is stamped to delimit compartments between the perimeter plane 30 and the partitions 34 and 36. There are four compartments here: two compartments 38 and 40 near one of the edges 32 and two other compartments 42 and 44 near the other edge 32.

It will be understood that when the fluid box 28 is placed and brazed against the flat surface 24, the longitudinal bulkhead 34 is placed in the position designated by the same reference in FIG. 1 and that the transverse partition 36 is placed between two openings 26 of the plate collector 22.

Figure 3 shows the periphery 30 of the fluid box 28 applied against the periphery of the bearing surface 24 formed by the collector plate 22, the latter being brazed on the collector 16. In the example shown, it is provided for at least one tab 45 coming from one edge of the manifold 16 and folded over one edge of the fluid box 28 to ensure provisional maintenance of the assembly for soldering.

Alternatively, the tab 45 could come from an edge of the manifold plate 22 or fluid box 28 and be folded respectively over an edge of the collector 16 or of the manifold plate 22.

In the example, the longitudinal partition 34 of the box fluid (Figure 1) is placed, for each tube, against the end of a longitudinal partition 78 of the tube. This allows to later solder the partition 34 of the box to fluid against a partition 78 of each tube and, thus, of separate each tube into two groups: a first group G1 formed here of three channels and a second group G2 formed here of four channels.

This allows to define in the heat exchanger different circulation passes divided into two layers, namely a first layer formed by the group G1 of the channels and a second layer formed by the group G2 of the channels.

We will now explain the invention in more detail in reference to FIG. 4 which describes an example of an exchanger heat produced as defined above.

It can be seen in FIG. 4 that the heat exchanger comprises a bundle formed of a plurality of tubes 10 as defined previously, these tubes 10 being received, at their end upper, in a collector 16 on which is brazed a manifold plate 22, as defined above.

At their lower end, the tubes 10 are received in a analog collector (not shown) on which is brazed another identical collecting plate 22.

These two collecting plates 22, respectively arranged in upper and lower part, serve as plates of reference to receive a first fluid box 28 (in upper part) and a second fluid box 46 (in lower part).

The fluid box 28 is made in accordance with the teachings in Figure 2. In the example, this fluid box includes a flat periphery 30 of generally rectangular shape, a longitudinal partition 48 which extends only over one part of the length which connects a transverse edge 50 of the periphery to a transverse partition 52. Perimeter 30 and the partitions 48 and 52 are coplanar.

The fluid box 28 is produced by stamping for further define an inlet manifold 54 and a manifold outlet 56 which communicate respectively with two compartments 58 and 60, which are separated by the longitudinal partition 48. In addition, the fluid box 28 forms a part in dome 62 delimiting a single compartment 64.

The fluid box 46 has a flat periphery 66 of shape general rectangular and a longitudinal partition 68 which spans the entire length and which is coplanar with the periphery 66. The fluid box 46 comprises two bosses longitudinal 70 and 72 defining two compartments corresponding elongates which communicate with the beam.

This defines a heat exchanger comprising a plurality of tubes 10, possible spacers (not shown), two collectors 16 (of which only one is shown), two collector plates 22, as well as a box fluid 28 in the upper part and a fluid box 46 in lower part.

The partition 68 of the fluid box 46 is provided for dividing each tube in such a way that compartment 70 communicates with G1 group channels and compartment 72 with the channels of group G2.

Fluid circulation in the heat exchanger takes place in several passes as shown in Figure 5. The fluid enters compartment 58 through inlet manifold 54 and circulates in a first sub-layer SN1 formed by the channels of group G1 belonging to part of the tubes for gain compartment 70 by a vertical circulation of top to bottom.

Then the fluid flows from bottom to top from the same compartment 70 to reach compartment 64, traffic taking place in a second SN2 sub-layer. In this second sub-layer, the fluid circulates in the group G1 of the channels of the other tubes of the bundle.

Then, the fluid reaches compartment 72 by circulation vertical from top to bottom in a third SN3 sublayer, circulation taking place in the channels of the G2 group part of the tubes.

Finally, the fluid reaches compartment 60 by circulation vertical from bottom to top in a third SN4 sublayer, the circulation of the fluid taking place in group G2 of channels of the other tubes. The fluid leaves the heat exchanger heat through the outlet pipe 56.

Thus, the circulation of the fluid is carried out in four passes and in alternate directions. The first two passes correspond SN1 and SN2 respectively. These two sub-layers belong to the same layer which extends to near the large face F1 of the heat exchanger. The circulation then takes place in two other passes which correspond to the SN3 and SN4 sub-layers. These two tablecloths are part of a second tablecloth which is connected in series at the first layer and which extends parallel to the large face F2 of the heat exchanger. We will understand that the first layer is formed by the groups G1 of the channels (here three in number) and the second layer by the group G2 channels (here four in number).

We now refer to Figure 6 which shows a tube extruded 10 according to the invention which comprises a multiplicity of channels 12, in the example eleven in number.

These channels each have a substantially shaped section rectangular. The tube comprises two flat faces 74 joined together by two semi-circular faces 76. The tubes are separated by partitions 78 which have variable thicknesses. The two partitions 78 located in the central region have a thickness A and they are each followed by partitions having respective thicknesses B, C, D and E such that A> B> C> D> E. The thicknesses of the partitions thus decrease by the central region on the outskirts.

In the embodiment of Figure 7, the tube 10 is formed from a sheet 80 folded so as to include two opposite planar faces 82 joined by two end faces 84 of semi-circular profile. The sheet 80 has two longitudinal edges 86 assembled respectively against a intermediate part 88 of the stepped structure sheet forming a partition wall. The two edges 86 are assembled by longitudinal brazed joints 88 so to close the tube and define two channels 12.

In the embodiment of Figure 8, the tube 10 is formed from two stamped sheet metal plates 90 which are mutually brazed tightly. These two plates 90 have symmetrical profiles and each have two edges longitudinal end 92 and a central longitudinal edge 94, parallel to each other, which separate two bosses 96. The plates 90 are mutually tightly soldered speakers respective edges so as to define two channels 12.

The heat exchanger in Figure 9 is similar to that of Figure 4 but differs however in the structure of the fluid box 28 in the upper part and by the structure of the fluid box 46 in the lower part (Figure 10).

The fluid box 28 comprises, as in the case of the figure 4, an inlet manifold 54 and an outlet manifold 56 which communicate respectively with two compartments 58 and 60 separated by a longitudinal partition 48. But, the partition 48 continues beyond the transverse partition 52 for define two other compartments 98 and 100.

The fluid box 46 has a longitudinal partition 68 which extends over part of its length and which joins a transverse partition 102. Another transverse partition 104 is provided at a distance from the partition 102. As a result, the fluid box 46 delimits two longitudinal compartments adjacent 70 and 72 on either side of the partition 68 and two transverse compartments 106 and 108 on both sides of the partition 104.

The circulation of the fluid in the heat exchanger of Figures 9 and 10 are carried out in six passes divided in two plies. In the first layer, the fluid circulates successively in the first group of channels passing successively by compartments 54, 70, 98 and 106, 98 and 108. Then, in the second layer, the fluid circulates successively in the second group of channels passing successively by compartments 108 and 100, 106 and 100, 72 and 56.

The invention thus makes it possible to produce a heat exchanger obtained by brazing metal parts advantageously at aluminum base. The use of multi-channel tubes allows to define, in each tube, at least two groups of channels corresponding respectively to at least two layers of circulation. Because each collector offers a surface flat to bring back the collector plate, this allows to obtain a perfect seal between this flat surface and the fluid box and define compartments for the circulation of the fluid in several passes.

In particular, the invention makes it possible to produce an exchanger heat with circulation in two layers, which leads to better temperature balancing of the exchanger. This is particularly interesting in the case where the heat exchanger is made in the form of a evaporator.

In each tablecloth, at least two passes can be provided, usually two, three or four passes.

In general, the invention makes it possible to simplify the method of assembling the heat exchanger while providing a seal.

In addition, the heat exchanger thus produced has a reinforced resistance to bursting and reduces pressure constraints on the fluid boxes and collectors, since each of the fluid boxes can have a lower height.

The invention finds a particular application in the heating and / or air conditioning equipment for motor vehicles.

Claims (13)

1. Heat exchanger, in particular evaporator, comprising a bundle of tubes that is mounted between two fluid boxes by means of respective manifolds and is capable of being traversed by a fluid, in which heat exchanger the tubes (10) each comprise several ducts (12) separated by at least one longitudinal partition (68) and are arranged in a single row, parallel to two large faces (F1, F2) of the exchanger, the flow of the fluid taking place in at least two layers (SN1, SN2; SN3, SN4) parallel to the large faces of the exchanger and each formed by a part (G1, G2) of the ducts (12) of the tubes, and at least one of the fluid boxes (28, 46) comprises an internal longitudinal partition (48, 68) capable of dividing the manifold box into at least two longitudinal compartments communicating with the two layers, respectively, characterized in that each manifold (16) comprises openings (18) surrounded by flanges (20) for the introduction of the tubes of the bundle and is provided with a plane surface (22, 24), and in that each fluid box (28, 46) comprises a plane periphery (30, 66) and at least one coplanar partition (48; 52; 68) that are capable of being brazed against the plane surface (24) of the manifold (16).
2. Heat exchanger according to Claim 1, characterized in that at least one (28) of the fluid boxes comprises at least one transverse partition (52) capable of dividing the fluid box into at least two transverse compartments (58, 60, 64), at least one of which establishes a communication between two layers.
3. Heat exchanger according to either of Claims 1 and 2, characterized in that each layer is divided into at least two sub-layers (SN1, SN2, SN3, SN4) connected in series and in which the flow of the fluid takes place in counter-current mode from one sub-layer to the next.
4. Heat exchanger according to one of Claims 1 to 3, characterized in that the plane surface (24) of each manifold (16) forms part of a manifold plate (22) attached by brazing to the manifold and comprising openings (26) aligned with the openings (18) of the manifold.
5. Heat exchanger according to Claim 4, characterized in that it comprises at least one lug (45) originating from one edge of the manifold (16) or of the manifold plate (22), or of the fluid box (28, 46), the said lug being folded over respectively onto one edge of the fluid box (28, 46), or onto one edge of the manifold (16) or of the manifold plate (22).
6. Heat exchanger according to one of Claims 1 to 5, characterized in that the end (14) of at least one longitudinal partition (78) of the tube (10) is positioned substantially at the level of the plane surface (22, 24), in such a way that this longitudinal partition (78) of the tube can be brazed onto an internal longitudinal partition (48, 68) of the fluid box.
7. Heat exchanger according to one of Claims 1 to 6, characterized in that the fluid boxes (28, 46) are each formed by stamping a metal plate in order to define the plane periphery (30, 66) and the coplanar partition or partitions.
8. Heat exchanger according to one of Claims 1 to 7, characterized in that at least one of the fluid boxes (28, 46) comprises at least one fluid inlet or outlet pipe (54, 56).
9. Heat exchanger according to one of Claims 1 to 8, characterized in that each tube (10) is an extruded tube.
10. Heat exchanger according to one of Claims 1 to 8, characterized in that each tube (10) is formed from a metal sheet (80) folded and closed by longitudinal brazed joints (88).
11. Heat exchanger according to one of Claims 1 to 8, characterized in that each tube (10) is formed from two stamped sheet metal plates (90) that are brazed together so as to be leaktight.
12. Heat exchanger according to one of Claims 1 to 11, characterized in that the ducts (12) of the tubes (10) are separated by partitions (78) having respective thicknesses (A, B, C, D, E) that decrease from a central region of the tube towards the periphery.
13. Heat exchanger according to one of Claims 1 to 12, characterized in that it is produced in the form of an evaporator for an air-conditioning apparatus.

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