EP0505242B1 - Heat exchanger with several rows of tubes, more particularly for motor vehicle - Google Patents

Description

The invention relates to a heat exchanger of the type comprising a bundle of parallel tubes arranged in rows and having respective ends received in a collecting plate provided with holes, which are optionally surrounded by collars.

Such heat exchangers are used in particular in motor vehicles with an internal combustion engine to provide either cooling of the engine or heating of the passenger compartment. The bundle tubes are then traversed by a fluid used for cooling the engine, while air circulates between the bundle tubes.

In some cases, the bundle tubes have a non-circular section, in particular a flattened section of oval, elliptical or oblong type, so as to reduce the pressure drop undergone by the air flow passing through the heat exchanger and at optimize the thermal performance of the latter.

In known heat exchangers of this type, there are 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 tightly connected to the collector plate, and in particular the collar, if present, which surrounds the hole.

The collector plate, also called a "hole plate", is generally produced in the form of a metal plate in which the holes and the corresponding collars are arranged. The seal between each end of the tube and the corresponding collar is then obtained either by interposing a compressible seal, or by direct brazing, the tube then being provided with an easily fusible metal plating.

As these heat exchangers are formed from several rows of tubes, the collector plate must also include several rows of holes which are separated from each other by a given center distance within the same row and by another given center distance d 'one row to another. There is thus between two consecutive holes in the collector plate a thickness of material which, for reasons of mechanical strength of the collector plate, cannot fall below a minimum value, this minimum value being essentially essential for the realization of collars if the collector plate has them.

As a result, it is not possible to optimize the dimensions of the tubes and the spacings and therefore the thermal performance of the heat exchanger, and this for given dimensions of the collector plate.

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

It therefore proposes a heat exchanger of the type comprising a bundle of parallel tubes arranged in rows, and the ends of which are received in a collecting plate provided with holes, possibly surrounded by collars.

According to an essential characteristic of the invention, each hole of the manifold receives the respective ends of several adjacent tubes and in that a compressible seal is interposed between each hole and the ends of tubes received in this hole.

Under these conditions, the center distance or not of the tubes can be brought to a minimum value. It is thus possible to optimize the performance of the heat exchanger and this for minimum dimensions of the collector plate.

As each hole of the collector plate receives the respective ends of several tubes and since it can also be surrounded by a collar, the collector plate is thus stiffened, which results in better resistance to pressure.

Advantageously, this seal comprises a core suitable for being applied to the collector plate and provided with compressible collars corresponding to the holes in the collector.

Each compressible collar is suitable for being interposed between a hole in the collector plate and the ends of the tubes received in this hole, this compressible collar providing bridges of material between two ends of adjacent tubes received in the same hole.

Under these conditions, each of the compressible collars of the seal provides sealing between, on the one hand, the hole of the collector plate and, on the other hand, the ends of tubes received in this hole.

Thus, in the case where the bundle of the heat exchanger comprises two rows of tubes, each compressible collar comprises a single bridge of material. In the case where it is a bundle with three rows of tubes, the compressible collar comprises two bridges of material.

The invention applies in particular to a collector plate whose holes are provided with collars.

Advantageously, each bridge of material of the compressible collar is reinforced by a heel which aims to limit the entrainment of the elastic material constituting the seal during the introduction of the ends of the tubes of the bundle.

To limit this entrainment of material, the invention further provides for having a comb-shaped bar embedded in the thickness of the joint to reinforce the adjacent material bridges.

• la figure 1 est une vue partielle de dessus d'une plaque collectrice selon la première forme de réalisation précitée;
• la figure 2 est une vue en coupe suivant la ligne II-II de la figure 1;
• la figure 3 est une vue partielle de dessus d'un joint d'étanchéité destiné à équiper la plaque collectrice des figures 1 et 2;
• la figure 4 est une vue en coupe suivant la ligne IV-IV de la figure 3;
• la figure 5 est une coupe transversale partielle d'un échangeur de chaleur comprenant un faisceau de tubes assemblés sur la plaque collectrice des figures 1 et 2 au moyen du joint d'étanchéité des figures 3 et 4;
• la figure 6 est une vue partielle de dessus d'une plaque collectrice munie d'un joint d'étanchéité et recevant les extémités des tubes d'un faisceau, selon une variante de réalisation;
• la figure 7 est une vue en coupe suivant la ligne VII-VII de la figure 6;
• la figure 8 est une vue en coupe suivant la ligne VIII-VIII de la figure 6.

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

• Figure 1 is a partial top view of a header plate according to the first embodiment mentioned above;
• Figure 2 is a sectional view along line II-II of Figure 1;
• Figure 3 is a partial top view of a seal intended to equip the header plate of Figures 1 and 2;
• Figure 4 is a sectional view along line IV-IV of Figure 3;
• Figure 5 is a partial cross section of a heat exchanger comprising a bundle of tubes assembled on the header plate of Figures 1 and 2 by means of the seal of Figures 3 and 4;
• Figure 6 is a partial top view of a header plate provided with a seal and receiving the ends of the tubes of a bundle, according to an alternative embodiment;
• Figure 7 is a sectional view along line VII-VII of Figure 6;
• FIG. 8 is a sectional view along line VIII-VIII of FIG. 6.

Reference is first made to FIGS. 1 and 2 which represent a collecting plate 10, also called a plate with holes, of generally rectangular shape. The plate 10 has a core 12 of generally rectangular shape, preferably formed of a metallic material, and limited by two parallel edges 14 corresponding to the two long sides of the rectangle and two other parallel edges (not shown in the drawings), corresponding to the small sides of the rectangle.

As shown in FIG. 2, each of the edges 14 comprises firstly a part 16 connected at right angles to the core 12, a part 18 connected at right angles to the part 16 and finally a part 20 connected at right angles to the part 18. The parts 16 and 18 of each edge 14 thus define a groove 22 extending over the entire periphery of the plate 10 and the function of which will be explained below. Each of the parts 20 is crenellated on its free edge to define a series of lugs 24 capable of being folded down to ensure the assembly of the collector plate with a wall of water box (not shown).

Through the core 12 of the collector plate 10 are formed oblong holes 26, identical to each other, three of which are visible in Figure 1. Each of the holes 26 has, in the direction of its length, an axis of symmetry XX ′ Which extends perpendicular to the edges 14 of the collector plate 10. Each of the holes 26 is formed by the union of two identical oval sections 28 which intersect at a throttle 30. In the example, the two sections 28 are elliptical, their respective major axes being aligned in the direction of the axis XX ′. The respective centers of the two elliptical sections 28 define between them an axis spacing P. In addition, the distance between two adjacent holes 26 defines an axis E whose direction is perpendicular to that of the pitch P. Each of the holes 26 is surrounded by a collar 32 whose contour corresponds to that of the two sections 28 including their throttle 30. Each of the collars 32 projects relative to the core 12, on the side opposite to the tabs 24.

It will be understood that each hole 26 is intended to receive the respective ends of two tubes belonging to two adjacent rows of a bundle formed of two rows of tubes. Within a single row, the tubes are separated two by two by an E-axis.

Referring now to Figures 3 and 4 which show a seal 34 intended to be applied to the collector plate 10. The seal 34, made of a compressible elastomeric material, comprises a core 36 of generally rectangular shape corresponding to that of the core 12 of the collecting plate 10. The core 36 is limited by two longitudinal beads 38 corresponding to the two long sides of the rectangle and two lateral beads (not shown) corresponding to the short sides of the rectangle. The beads 38 are attached to the core 36 by a veil of material 40. This gives a bead extending over the entire periphery of the seal and suitable for being introduced into the groove of the collector plate.

The core 36 is provided with compressible collars 42 each of which has a shape adapted to that of a hole 26 so as to be able to be introduced into the latter when the core 36 of the seal 34 is applied against the core 12 of the collector plate 10 .

Each collar 42 thus affects the general shape of an 8 formed by two oval parts 44 joined together by a bridge of material 46. Thus, when a compressible collar 42 of the seal 34 is introduced into a collar 32 of a collector plate 10, the two parts 44 of the collar 42 engage respectively in the two sections 28 of the hole 26, the material bridge 46 coming to be placed in the constriction 30. The core 36 forms, inside each compressible collar 42, two orifices 48 suitable for receiving each, as will be seen below, one end of a tube of the bundle.

As shown more particularly in Figure 4, each material bridge 46 is reinforced by a heel 50 intended to limit the entrainment of the material of the seal during assembly of the bundle of tubes.

We now refer to FIG. 5 which shows a bundle 52 formed of two rows of tubes 54 of non-circular section which cross a multiplicity of parallel fins 56. The tubes 54 are separated two by two with a center distance E within the same row and with a pitch P from one row to another. The tubes 54 have respective ends 58 of non-circular shape spaced from one another with the same center distance and the same pitch as the tubes.

The shape of the holes 26 of the collector plate 10 and the shape of the compressible beads 42 and the orifices 48 of the seal 34 are adapted to that of the ends 58 of the tubes 54.

To assemble the bundle 52 on the collecting plate 10, the gasket 34 is first placed on the collecting plate 10 and the ends 58 of the bundle tubes are then introduced into the perforations 48 of the joint 34.

The ends 58 can be introduced into the holes 48 and then be flared to ensure the compression of the seal, in a manner known per se.

As a variant, it is possible to compress each of the beads 42 beforehand using a punch and then to introduce the ends 58, and this also in a manner known per se.

After introduction of the ends 58, the latter can be flared over their entire periphery or over part of their periphery so as to prevent inadvertent separation of the collector plate and the bundle.

Since each material bridge 46 of the seal 34 has a heel 50, the entrainment of the seal material is limited during the passage of the prestressing punches or during the introduction of the ends 58 of the tubes.

In the embodiment of FIGS. 6 to 8, to which reference is now made, the seal 34 comprises a bar 60, in the form of a comb, which is embedded in the thickness of the seal to reinforce the bridges of material 46 from each of the compressible beads 42. The bar 60 comprises a core 62, intended to extend over the length of the joint 34 by crossing each of the bridges of material 46, and provided with a multiplicity of teeth 64 whose distance mutual corresponds to the center distance E.

It will be understood that the presence of the bar 60, which is advantageously a molded metal bar, is opposed to the entrainment of the material of the seal during assembly of the bundle of tubes.

In the embodiment of FIGS. 1 to 5, as in the embodiment of FIGS. 6 to 8, after assembly of the beam on the collecting plate 10, the latter receives a wall with an open face to form a water box , this wall being connected to sealing by folding down the tabs 24.

In the various embodiments mentioned above, the other end of the bundle is advantageously provided with a similar collecting plate.

Although the invention has been described with reference to tubes of circular section, it should be understood that it also applies to tubes of circular section provided that appropriate holes are provided in the collector plate.

It will be understood that, thanks to the invention, it is possible to produce a heat exchanger with a minimum pitch between two tubes of two adjacent rows. This results in optimal performance for a minimum width of the collector plate while improving the pressure resistance of the tubes.

Claims (7)

1. A heat exchanger of the type comprising a bundle of tubes disposed in rows, the respective end portions of the tubes being received in a header plate formed with holes, characterised in that each hole (26) in the header plate (10) receives the respective end portions (58) of a plurality of adjacent tubes (54), and in that a compressible sealing gasket (34) is interposed between each hole (26) and the end portions (58) of the tubes received in that hole.
2. A heat exchanger according to Claim 1, characterised in that the sealing gasket (34) comprises a spine portion (36) which is adapted to be applied on the header plate (10), and which is provided with compressible collar portions (42) corresponding with the holes (26) in the header plate (10).
3. A heat exchanger according to Claim 1 or Claim 2, characterised in that each compressible collar portion (42) is adapted to be interposed between a hole (26) and the end portions (58) of the tubes (54) received in that hole, and in that the said compressible collar portion (42) defines an integral bridge (46) between the respective end portions (58) of two adjacent tubes (54) received in that hole.
4. A heat exchanger according to Claim 3, characterised in that each integral bridge (46) is reinforced by a projection (50).
5. A heat exchanger according to Claim 3 or Claim 4, characterised in that it includes a comb-shaped bar (60) embedded within the thickness of the gasket (34) so as to reinforce the adjacent integral bridges (46).
6. A heat exchanger according to one of the preceding Claims, characterised in that the end portions (58) of the tubes (54) are part of different rows in the bundle.
7. A heat exchanger according to one of the preceding Claims, characterised in that each hole (26) is formed with a collar portion (32).

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