EP0709642A1 - Heat exchanger with tubular leader box - Google Patents

Abstract

The heat exchanger consists of two tubular manifolds (12) connected by a series of flat tubes (18) which have their ends sealed in slots (22) in the manifold walls. Each manifold is made from two linked halves (56,58) which are generally semi-cylindrical in shape and connected by lengthwise assembly edges (62,66) which are offset radially from the manifold walls. The two halves of each manifold have the same radius of curvature (R), and one has assembly edges which are offset inwards and the other assembly edges which are offset outwards, so that the two pairs of assembly edges overlap one another. They are then joined together by brazing.

Description

The invention relates to a heat exchanger with tubular manifolds, in particular for a motor vehicle.

It relates more particularly to a heat exchanger of the type comprising two manifolds with tubular walls and with a bundle of flat tubes, the ends of which are sealingly engaged in slots made in the wall of each manifold, and in which each manifold is formed of two complementary parts of generally semi-cylindrical shape, joined together by longitudinal edges of assembly of conjugate shapes.

Heat exchangers of this type are already known, for example from US Patent 5,125,454.

In this type of heat exchanger, the bundle further comprises corrugated spacers forming cooling fins and disposed between the tubes of the bundle, the assembly being usually brazed to the two manifolds.

The use of tubular walls, in particular circular cylindrical walls, makes it possible to obtain manifolds resistant to high internal pressures, such as those produced by certain fluids in the case of a motor vehicle. As fluids at high pressure, mention may in particular be made of the charge air of a turbocharged engine, the lubricating oil of the engine, etc.

In a heat exchanger according to US Pat. No. 5,125,454, the two complementary parts of generally semi-cylindrical shape of each manifold have different diameters, so that one of the two complementary parts fits inside from the other complementary part.

This results in a difficulty in positioning and maintaining the two complementary parts with each other before the brazing operations.

This solution therefore requires complex tools and delicate operations to be implemented.

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

To this end, it offers a heat exchanger of the type defined in the introduction, in which each of the two complementary parts comprises a semi-cylindrical wall extended by two longitudinal assembly edges offset radially with respect to the wall.

Thus, the position and the maintenance of the two complementary parts can be easily obtained due to the offset of their assembly edges, which makes it possible to provide support for the subsequent brazing operations.

The manifold thus produced has a cylindrical wall in the broad sense, that is to say a wall with parallel generators resting on a closed curve which preferably has the shape of a circle or an approaching shape.

Advantageously, the respective assembly edges of the two complementary parts of the manifold extend parallel to the guidelines of the cylinder formed by the meeting of these two complementary parts.

Preferably, the two complementary parts are of semi-circular section.

In this case, the two complementary parts of circular section have substantially the same radius.

According to an advantageous characteristic of the invention, the heat exchanger comprises a first complementary part having internal longitudinal edges offset radially inwards to come into abutment against the internal face of the semi-cylindrical wall of a second complementary part, while this second complementary part has external longitudinal edges offset radially outward for come to bear against the external face of the semi-cylindrical wall of the first complementary part.

An excellent form cooperation is thus obtained in the assembly of the two complementary parts of the manifold.

In a preferred embodiment of the invention, the external longitudinal edges of the second complementary part are provided with retaining tabs folded radially inwards to ensure the provisional maintenance of the two complementary parts before their final assembly.

It follows that the two complementary parts of the manifold are held in position for their subsequent assembly, which is advantageously carried out by brazing.

It then suffices to make the two complementary parts from a sheet coated, preferably on its two faces, with a suitable brazing alloy.

According to another characteristic of the invention, the slots are made in one of the two complementary parts.

According to another characteristic of the invention, each manifold is provided with two end walls joined to the two complementary parts.

• la figure 1 est une vue en élévation d'un échangeur de chaleur à boîtes collectrices tubulaires selon l'invention;
• la figure 2 est une vue en élévation, et à échelle agrandie, d'une boîte collectrice de l'échangeur de la figure 1;
• la figure 3 est une vue en coupe selon la ligne III-III de la figure 2; et
• la figure 4 est une vue en coupe axiale, et à échelle agrandie, de l'une des boîtes collectrices de l'échangeur de chaleur de la figure 1.

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

• Figure 1 is an elevational view of a heat exchanger with tubular manifolds according to the invention;
• Figure 2 is an elevational view, on an enlarged scale, of a manifold of the exchanger of Figure 1;
• Figure 3 is a sectional view along line III-III of Figure 2; and
• FIG. 4 is a view in axial section, and on an enlarged scale, of one of the manifolds of the heat exchanger of FIG. 1.

First of all, reference is made to FIG. 1 which represents a first heat exchanger 10 and a second heat exchanger 30 according to the invention, arranged side by side or paired and both comprising a similar structure.

The heat exchanger 10 comprises two tubular manifolds 12 and 14 with respective axes XX and YY. Between the two manifolds 12 and 14 is mounted a bundle 16 formed of a multiplicity of flat tubes 18, parallel to each other, and a multiplicity of corrugated inserts 20 forming fins and disposed between the tubes 18. The latter have, in the example, a rectangular cross section.

The ends of the tubes 18 of the bundle are engaged, on one side, in slots 22 made in the wall of the manifold 12 and, on the opposite side, in similar slots 24 made in the wall of the manifold 14.

The manifolds 12 and 14 are provided with two pipes 26 and 28 respectively serving for the entry and exit of a first fluid, as shown by the arrows F1 and F2.

For example, the first fluid is supercharging air from a turbocharged engine which must be cooled by an air flow externally sweeping the tubes 18 and the spacers 20 of the bundle 16.

The heat exchanger 30 comprises two manifolds 32 and 34 attached respectively to the manifolds 12 and 14 and aligned with the latter.

Thus, the manifold 32 is axially aligned with the manifold 12, while the manifold 34 is axially aligned with the manifold 14.

The manifolds 32 and 34 are also joined by the bundle 16, the ends of the tubes 18 being engaged, on one side, in slots 36 of the manifold 32 and, on the opposite side, in slots 38 of the manifold 34.

In addition, the manifolds 32 and 34 are provided with an inlet manifold 40 and an outlet manifold 42 serving respectively for the inlet and outlet of a second fluid, as shown by the arrows F3 and F4.

For example, this second fluid can be engine lubricating oil, which should be cooled by heat exchange with an air flow.

It will be understood that it is the same air flow which can thus cool the first fluid and the second fluid which pass respectively through the first heat exchanger 10 and the second heat exchanger 30.

As can be seen in FIG. 1, the pipes 26 and 28 are integral with two end walls 44 and 46 forming part of the manifolds 12 and 14, while the pipes 40 and 42 are integral with two end walls 48 and 50 forming part of the manifolds 32 and 34.

In addition, two walls 52 and 54, forming partitions, are interposed respectively between the manifolds 12 and 32 and between the manifolds 14 and 34.

Thus, the circulation circuits of the first fluid and the second fluid are completely separate.

Reference is now made to FIGS. 2 and 3 to describe more particularly the structure of the manifold 12, note being made that the structure of the other manifolds 14, 32 and 34 is similar.

The manifold 12 is formed of two complementary parts 56 and 58 of generally semi-cylindrical shape which, when joined together, have substantially the shape of a circular cylinder of axis XX.

Part 56 comprises a circular semi-cylindrical wall 60 of axis XX and internal radius R, which extends over a little more than 180 ° (FIG. 3). The wall 60 is extended by two longitudinal assembly edges 62, forming two narrow bands, and offset radially inwards relative to the wall 60. The two longitudinal edges 62 extend in directions parallel to the generatrices of the cylinder d axis XX and each have an external face of cylindrical configuration and having substantially the radius R.

The two assembly edges 62 are intended to cooperate with the complementary part 58 and at the same time serve as a translation stop for the tubes 18.

Part 58 includes a semi-cylindrical wall 64 of circular section and radius R which extends over a little less than 180 ° (FIG. 3).

In the wall 64 are formed the slots 22 intended to receive the ends of the tubes 18, while the wall 60 of the part 56 is not perforated.

The wall 64 is extended by two longitudinal assembly edges 66 offset radially outwards and produced in the form of two narrow strips extending parallel to the directors of the cylinder with axis XX.

The internal face of the assembly edges 66 is capable of coming to bear against the external face of the wall 60, in the region of this wall which is immediately adjacent to the assembly edges 62.

The longitudinal edges 66 of the part 58 are each provided with two holding tabs 70 (FIGS. 2 and 3) which are folded radially inwards to ensure the provisional holding of the two complementary parts 56 and 58 once assembled.

The tabs 70 are slightly folded inwards and thus provide an elastic bearing force which tends to maintain contact between the assembly edges 62 and the wall 64 and between the assembly edges 66 and the wall 60.

The complementary parts 56 and 58 are advantageously formed from a metal sheet coated, on each of its faces, with a brazing alloy.

The slots 22 are preferably made in the thickness of the wall of the part 58 previously formed to the desired shape.

Because the complementary parts 56 and 58 can be held together, in their correct assembly position, it then suffices to pass the heat exchanger to the oven to ensure the connection between the two complementary parts 56 and 58 and also ensure the connection of the manifolds to the bundle 16, that is to say to the tubes 18 and to the spacers 20.

Reference is now made to FIG. 4 which shows more particularly the structure of the two manifolds 12 and 32 aligned along the axis XX.

The end wall 44 is of generally circular shape and is internally lined with a counter-plate 72 of circular shape, and of smaller diameter. These structures facilitate the provisional retention of the end wall 44 before brazing.

As can be seen in FIG. 4, the tubing 26 passes through two aligned holes 74 and 76 made respectively through the wall 44 and the counterplate 72. The tubing 26 comprises two spaced beads 78 and 80 extending respectively from on either side of the partition 44 and of the counter plate 72 in order to maintain these three elements together.

The end wall 48 is internally provided with a counter plate 82 similar to the counter plate 72.

In addition, the intermediate wall 52 forming a partition is provided with two opposite counter-plates 84 and 86 facilitating the assembly of the two manifolds 12 and 32 in the extension of one another.

The exchanger of FIG. 1 can be easily produced by brazing, its constituent parts being held together when passing through the brazing furnace.

Of course, the invention is not limited to a heat exchanger, of the double type, as shown only by way of example in FIG. 1.

Thanks to the invention, the slots made in the walls of the manifolds can be produced easily with a simplified tool, since the machining of the slots is carried out on a semi-cylindrical part and not on a cylindrical part.

The invention finds a very particular application to heat exchangers for motor vehicles.

Claims (9)

Heat exchanger comprising two manifolds (12,14) with tubular walls and a bundle (16) of flat tubes (18) the ends of which are engaged in sealing in slots (22,24) formed in the wall of each manifold , and in which each manifold (12) is formed of two complementary parts (56, 58) of generally semi-cylindrical shape joined together by longitudinal assembly edges (62, 66) of conjugate shapes, characterized in that each of the two complementary parts (56,58) comprises a semi-cylindrical wall (60,64) extended by two longitudinal assembly edges (62,66) offset radially relative to the wall. Heat exchanger according to claim 1, characterized in that the joining edges (62, 66) of the two complementary parts (56, 58) extend parallel to the guidelines of the cylinder formed by the union of the two complementary parts. Heat exchanger according to one of claims 1 and 2, characterized in that the two complementary parts (56,58) are of circular section. Heat exchanger according to claim 3, characterized in that the two complementary parts (56, 58) of circular section have substantially the same radius (R). Heat exchanger according to one of claims 1 to 4, characterized in that a first complementary part (56) comprises two internal longitudinal edges (62) offset radially inwards to come into abutment against the internal face of the wall semi-cylindrical (64) of a second complementary part (58), while this second complementary part (58) comprises two external longitudinal edges (66) offset radially outwards to come into abutment against the external face of the wall semi-cylindrical (60) of the first complementary part (56). Heat exchanger according to claim 5, characterized in that the external longitudinal edges of the second complementary part (58) are provided with retaining tabs (70) folded radially inwards to ensure the provisional holding of the two complementary parts (56 , 58) before their final assembly. Heat exchanger according to one of claims 1 to 6, characterized in that the two complementary parts (56,58) are joined together by brazing. Heat exchanger according to one of claims 1 to 7, characterized in that the slots (22) are formed in one (58) of the two complementary parts. Heat exchanger according to one of claims 1 to 8, characterized in that each manifold (12) is provided with two end walls (44,52) joined to the two complementary parts (56,58).

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