EP0578568A1 - Heat-exchanger having a bundle with parallel tubes, particularly for motor vehicles - Google Patents

Abstract

The heat exchanger comprises a bundle (32) of parallel tubes, a manifold plate (10) provided with holes (26), each receiving the respective ends (40, 42) of several adjacent tubes (36, 38) belonging to one and the same group (34), as well as a compressible sealing gasket (24) interposed between the edge of the hole and the ends of the tubes of the group, at least one (40) of the ends of the tubes of a group of tubes received in one and the same hole of the manifold plate having geometrical characteristics which are different from those of the other end or ends (42) of the tubes of the group. Application especially to heat exchangers for motor vehicles. <IMAGE>

Description

The invention relates to a heat exchanger of the type comprising a bundle of parallel tubes having respective ends received in a collecting plate provided with holes.

Such heat exchangers are used in particular in motor vehicles with an internal combustion engine to form either a radiator for cooling the engine or a radiator for heating the passenger compartment. In either of these two applications, the tubes of the bundle are traversed by a fluid, generally water added with an antifreeze, used for cooling the engine, while a flow of air scans the beam tubes.

In known heat exchangers of this type, there are usually provided as many holes in the collector plate as there are tubes in the bundle, so that each end of the tube is individually received in a hole in the collector plate and is connected to sealing at the latter.

In French Patent Application No. 91 03411, in the name of the Applicant, a heat exchanger of the type has been proposed comprising a bundle of parallel tubes, a collecting plate provided with holes each receiving the respective ends of several adjacent tubes belonging to a same group. Generally, a compressible seal is interposed between the edge of the hole and the ends of the group tubes.

Due to the fact that the respective ends of the tubes of a group are received in a single hole of the collector plate, instead of being each received individually in a hole of this plate, the distance or not of the tubes can be brought to a minimum value.

It is thus possible to optimize the thermal performance of the heat exchanger for minimum dimensions of the header plate.

However, in the heat exchanger of the last mentioned type, the tubes of the same group belong to different rows of the bundle. In addition, this heat exchanger is more particularly suitable for bundles comprising two rows of tubes, that is to say bundles of the two-row type.

It is therefore an object of the invention to provide a heat exchanger of the last mentioned type which can be applied to other structures of the bundle.

It is also an object of the invention to provide such a heat exchanger which has a small footprint.

It is also an object of the invention to provide such a heat exchanger having high feasibility characteristics of the collector plate and / or of the assembly of the bundle on the collector plate.

The invention provides a heat exchanger of the aforementioned type, in which at least one of the ends of the tubes of a group of tubes received in the same hole of the collector plate has geometrical characteristics different from those of the other ( or other) end (s) of the group tubes.

By the expression "different geometrical characteristics" is meant to mean that the tube end considered may in particular have an orientation, a coaxiality and / or a section different from those of another or several other tube ends of the group.

It follows that the heat exchanger thus obtained has a smaller footprint and / or characteristics improved in feasibility only if all tube ends were similar, as previously planned.

Due to the differences in geometric characteristics mentioned above, the header plate of the heat exchanger of the invention may include bridges of more resistant materials between the holes in the header plate, which are each intended to receive a group of several tubes. .

In a first embodiment of the invention, the ends of the tubes of the group are arranged aligned and belong to the same row of tubes of the bundle.

Advantageously, the ends of the tubes of the group comprise two ends belonging to end tubes and at least one end belonging to an intermediate tube, the ends of the end tubes each being offset in the direction of the end of the intermediate tube which is adjacent to it.

As a result, it is thus possible to free up the space necessary to allow the lifting of collars each surrounding a hole in the collector plate.

Material bridges are also obtained, each extending between two adjacent holes in the collector plate, which ensures the mechanical strength of the latter.

This first embodiment of the invention applies in particular to a heat exchanger in which the ends of the tubes of the group have sections of oval or elliptical shape having respective major axes of symmetry extending in parallel directions. In this case, it is particularly advantageous for the end sections of the end tubes to be more elongated than the end section of the intermediate tube or tubes.

In a second embodiment of the invention, the tube ends of a group belong to different rows of the bundle, the group comprising at least three tubes, namely two end tubes and at least one intermediate tube, arranged aligned in a direction transverse to that of the rows.

This second embodiment of the invention applies in particular to a heat exchanger in which the ends of the tubes of the group have an oval or elliptical section having major axes of respective symmetry aligned.

According to the invention, provision is then made for the end of the intermediate tube or tubes to have a longer section than the ends of the end tubes.

Advantageously, the ends of the end tubes are each offset in the direction of the end of the intermediate tube which is adjacent to it.

A heat exchanger is thus obtained, the seal of which can have a minimum thickness between each end tube and the intermediate tube which is adjacent to it. In addition, the decentralization of the intermediate tube or tubes is thus limited.

In a third embodiment of the invention, in which the ends of the tubes of a group belong to different rows of the bundle, the group comprises at least three tubes, namely two end tubes and at least one intermediate tube, arranged in a staggered arrangement.

In this embodiment, the ends of the end tubes are advantageously oriented in the direction of the end of the intermediate tube which is adjacent to it.

In this way, the shape of the hole is optimized, while providing a bridge of material having sufficient mechanical strength between two adjacent holes.

This third embodiment of the invention also advantageously applies to a manifold in which the ends of the tubes have oval or elliptical sections each having a major axis of symmetry. According to the invention, the major axis of the section of the end of an end tube is advantageously oriented towards the section of the end of the intermediate tube which is adjacent to it.

• la figure 1 est une vue de dessus d'un échangeur de chaleur selon la première forme de réalisation précitée, montrant la plaque collectrice de l'échangeur et les extrémités des tubes qu'elle reçoit, le joint d'étanchéité étant supprimé pour simplifier le dessin;
• la figure 2 est une vue en coupe suivant la ligne II-II de la figure 1;
• la figure 3 est une vue en coupe suivant la ligne III-III de la figure 2;
• la figure 4 est une vue partielle de dessus d'un échangeur de chaleur selon la seconde forme de réalisation précitée, montrant une plaque collectrice de l'échangeur et les extrémités des tubes qu'elle reçoit, le joint d'étanchéité étant supprimé pour simplifier le dessin;
• la figure 5 est une vue en coupe selon la ligne V-V de la figure 4, le joint d'étanchéité étant ici représenté; et
• la figure 6 est une vue partielle de dessus d'un échangeur de chaleur selon la troisième forme de réalisation précitée, montrant une plaque collectrice de l'échangeur et les extrémités de tubes qu'elle reçoit, le joint d'étanchéité étant enlevé pour simplifier le dessin.

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

• Figure 1 is a top view of a heat exchanger according to the first embodiment above, showing the header plate of the exchanger and the ends of the tubes it receives, the seal being removed to simplify the drawing;
• Figure 2 is a sectional view along line II-II of Figure 1;
• Figure 3 is a sectional view along line III-III of Figure 2;
• Figure 4 is a partial top view of a heat exchanger according to the second embodiment above, showing a header plate of the exchanger and the ends of the tubes it receives, the seal being removed to simplify the drawing;
• Figure 5 is a sectional view along line VV of Figure 4, the seal being shown here; and
• Figure 6 is a partial top view of a heat exchanger according to the third embodiment above, showing a header plate of the exchanger and the tube ends which it receives, the gasket being removed to simplify the drawing.

The heat exchanger shown in Figures 1 and 2 comprises a header plate 10, also called "plate with holes", having a core 12 of generally rectangular shape, preferably formed of a metallic material. The plate is limited by two parallel edges 14 corresponding to the two long sides of the rectangle and two other parallel edges 16 (of which only one is visible in the drawing), corresponding to the short sides of the rectangle.

The edges 14 and 16 define a peripheral groove 18, of generally rectangular outline, which surrounds the core 12 of the collecting plate 10. The groove 18 is intended to receive a peripheral bead 20 (FIG. 2) forming part of a joint d seal 24 which covers the core 12 of the collector plate, in a manner known per se.

Through the core 12 are formed oblong holes 26, one of which is completely visible and another partially in FIG. 1. The holes 26 each have, in the direction of its length, an axis of symmetry XX which extends parallel and halfway between the edges 14, the axes of symmetry of the holes being thus aligned (FIG. 1).

Each of the holes 26 is bordered by a collar 28 (FIG. 2) and the seal 24 comprises, in correspondence with each hole 26, a collar 30 capable of coming to bear against the collar 28 of the hole.

The heat exchanger of FIGS. 1 and 2 further comprises a bundle 32 (FIG. 2) formed of a multiplicity of tubes arranged in a single row and distributed in several groups 34 consisting, in the example, of four tubes each, namely two end tubes 36 and two intermediate tubes 38. The tubes 36 have respective ends 40 and the tubes 38 respective ends 42 which are framed by the ends 40. The two ends 40 and the two ends 42 are introduced into a same hole 26 and ensure compression of the bead 30 of the seal 24.

The tubes 36, 38 have identical oval sections S (FIG. 3) each having a large axis A extending perpendicular to the edges 14 of the collector plate 10.

The tubes pass through a multiplicity of fins 44 which are parallel to each other.

The ends 40 and the ends 42 are flared to allow compression of the collar 30 of the seal inside the collar 28 of each hole 26 to guarantee a good seal at the connection of the tube ends with the collector plate.

Because of their widening, the ends 40 and 42 have a section different from that of section S of the body of the tube, shown in FIG. 3.

As shown in Figure 2, the end 40 of a tube 36 is offset in the direction of the end 42 of the intermediate tube 38 which is adjacent to it. The ends 40 and 42 thus have a center distance E 'which is less than the center distance E of the holes 38 and 36.

In this way, there is freed between two adjacent holes 26 sufficient space to allow the lifting of the collars 28 of the collector plate and also to allow the formation of a material bridge 46 of sufficient width to ensure the mechanical strength of the collector.

The end tubes 40 have sections S₁ each having a major axis of symmetry A₁ and the ends 42 each have a section S₂ having a major axis of symmetry A₂. The axes A₁ and A₂ extend in directions parallel to each other and perpendicular to the sides 14 of the collector plate 10. In addition, the sections S₁ of the ends 40 are more elongated than the sections S₂ of the ends 42.

Referring now to Figures 4 and 5 which show another heat exchanger according to the invention whose elements which correspond to those of the heat exchanger of FIGS. 1 and 2 are designated by the same reference numbers, increased by 100.

This heat exchanger comprises a collecting plate 110 of generally rectangular shape provided with several holes 126 of elongated shape each having, in the direction of its length, an axis of symmetry XX which extends perpendicular to the edges 114 of the collecting plate 110.

The heat exchanger here comprises a bundle 132 formed by a multiplicity of tubes arranged in three rows. These tubes are distributed in groups 134 each consisting of three tubes (two end tubes 136 and an intermediate tube 138) located adjacent and belonging to different rows of the bundle, the three tubes of a group being aligned. The tubes 36 and 38 all have sections of oval or elliptical shape identical or analogous to section S of FIG. 3, the respective main axes of the sections of the tubes of the same group being in the extension of one another .

The tubes 136 have respective ends 140 having an oval or elliptical section S₁ having a major axis A₁. The intermediate tube 138 has an end 142 having an oval or elliptical section S₂ of axis A₂. The two ends 140 frame the end 142 and are all three received in a hole 126 and are flared to cause the crushing of the collar 130 of the seal 124 against the collar 138 of the manifold plate 110. As can be seen best on In FIG. 4, the section S₂ of the end 142 is more elongated than the section S₁ of each of the ends 140.

In addition, each of the ends 140 is offset in the direction of the end 142 of the intermediate tube 138 which is adjacent to it. The ends 140 and 142 have a center distance E 'which is less than the center distance E of the corresponding tubes 136 and 138.

As a result, the seal 124 can have a minimum thickness between the end 142 and the two ends 140. In addition, since the end 142 has a section S₂ more elongated than the section S₁ of the ends 140, the limit is off-center ends 140.

In the embodiment of FIG. 6, to which we now refer, the numerical references of the elements common with the heat exchanger of FIGS. 1 and 2 are designated by the same numerical references increased by 200.

The collecting plate 210 here comprises several holes 226 each intended to receive the respective ends of three tubes of the same group 234 of tubes of the bundle. Each of the groups 234 comprises two end tubes 236 and an intermediate tube 238 which belong respectively to three different rows of the bundle and which are arranged in staggered rows. The three tubes have the same section, the respective major axes of the tube sections 236 being aligned and perpendicular to the edges 214 of the collector plate 210. The major axis of the tube section 238 is also perpendicular to the edges 214, but it extends parallel to the respective main axes of the sections of the tubes 236.

The end tubes 236 have respective ends 240 of oval or elliptical shape of section S1 having a large axis A₁, while the tube 238 has one end 242 of oval or elliptical shape of section S2 identical to that of the ends 240 and having a large axis of symmetry A₂. The major axis A₂ of the section of each of the ends 240 is oriented towards the section S₁ of the end 238 of the intermediate tube.

The major axis A₂ of the end 238 extends perpendicular to the edges 214 of the plate 210, while the respective major axes A₁ of the ends 240 extend in an oblique direction relative to the edges 214.

Each of the holes 226 has a shape adapted to receive the end 238 and the two ends 240, this shape resembling that of a U. This shape makes it possible to accommodate, in a single hole, the end 238 and the two ends 240 , while forming sufficient material bridges 246, between two adjacent holes 226, to ensure the mechanical strength of the collector plate 210.

It should be noted that this plate has, in its center, a hole 226 'having a general X-shaped structure suitable for receiving one end 242 surrounded by four ends 240.

The invention applies very particularly to the production of heat exchangers for a motor vehicle.

Claims (10)

1.- Heat exchanger of the type comprising a bundle of parallel tubes, a collecting plate provided with holes each receiving the respective ends of several adjacent tubes belonging to the same group, as well as a compressible seal interposed between the edge of the hole and the ends of the tubes of the group, characterized in that at least one (40; 140; 240) of the ends of the tubes of a group (34; 134; 234) of tubes received in the same hole (26; 126; 226) of the collector plate (10; 110; 210) has geometrical characteristics different from those of the other or of the other ends (42; 142; 242) of tubes of the group. 2.- heat exchanger according to claim 1, characterized in that the ends (40,42) of the tubes (36,38) of the group (34) are arranged aligned and belong to the same row of tubes of the bundle (32) . 3.- Heat exchanger according to claim 2, characterized in that the ends of the tubes of the group include two ends (40) belonging to end tubes (36) and at least one end (42) belonging to an intermediate tube (38 ), the ends (40) of the end tubes each being offset in the direction of the end (42) of the intermediate tube (38) which is adjacent to it. 4. Heat exchanger according to claim 3, wherein the ends (40,42) of the tubes (36,38) of the group (34) have sections (S₁, S₂) of oval or elliptical shape having respective axes ( A₁, A₂) extending in parallel directions, characterized in that the sections (S₁) of the ends (40) of the end tubes (36) are more elongated than the section (S₂) of the end (42) of the ( of) intermediate tube (s) (38). 5. A heat exchanger according to claim 1, wherein the ends (140,142) of the tubes (136,138) of a group (134) belong to different rows of the bundle (132), characterized in that the group (134) comprises at least three tubes, namely two end tubes (136) and at least one intermediate tube (138), arranged aligned in a direction transverse to that of the rows. 6. A heat exchanger according to claim 5, in which the ends (140,142) of the tubes (136,138) of the group (134) have an oval or elliptical section having respective major axes (A₁, A₂) aligned, characterized in that the end (142) of the intermediate tube or tubes (138) has a more elongated section than the respective ends (140) of the end tubes (136). 7.- Heat exchanger according to one of claims 5 and 6, characterized in that the ends (140) of the end tubes (136) are each offset in the direction of the end (142) of the intermediate tube (138) which is adjacent to it. 8.- heat exchanger according to claim 1, wherein the ends (240,242) of the tubes (236,238) of a group (234) belong to different rows of the bundle, characterized in that the group (234) comprises at least three tubes, namely two end tubes (236) and at least one intermediate tube (238), staggered. 9. Heat exchanger according to claim 8, characterized in that the ends (240) of the end tubes (236) are oriented towards the end (242) of the intermediate tube (238) which is adjacent to it. 10.- Heat exchanger according to one of claims 8 and 9, wherein the ends (240,242) of the tubes (236,238) have oval or elliptical sections each having a major axis of symmetry (A₁, A₂), characterized in that the major axis (A₁) of the section of the end (240) of an end tube (236) is oriented towards the section of the end (242) of the intermediate tube (238) which is adjacent to it.

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