WO2007048826A2

WO2007048826A2 - Collector box for a heat exchanger, particularly for a high-pressure fluid, exchanger comprising a box of this type and method for the production thereof

Info

Publication number: WO2007048826A2
Application number: PCT/EP2006/067830
Authority: WO
Inventors: Sylvain Hubert
Original assignee: Valeo Systemes Thermiques
Priority date: 2005-10-28
Filing date: 2006-10-26
Publication date: 2007-05-03
Also published as: FR2892805B1; WO2007048826A3; FR2892805A1

Abstract

The invention relates to a collector box for a heat exchanger comprising two half-tubes (12, 14) of generally identical profiles having a wall (16, 18) comprising assembly edges (20, 22, 24, 26) provided with complementary assembly forms (34, 36), the half-tube (12) being provided with openings (32) for inserting heat exchanger tubes. The inventive collector box is preferably used in heat exchangers flowed through by high-pressure coolant mediums functioning in a supercritical state as is the case of carbon dioxide (CO2).

Description

Collector box for heat exchanger, in particular for high-pressure fluid, exchanger comprising such a box and method for its manufacture

The invention relates to the field of heat exchangers and in particular to heat exchangers intended to be traversed by a fluid under high pressure.

In this respect, the invention relates more particularly to air conditioning exchangers capable of being traversed by a refrigerant fluid in the supercritical state, as is the case with natural gases such as carbon dioxide or CO ₂ . Such exchangers find particular application in motor vehicles. They can in particular constitute a qaz cooler in which the refrigerant leaving a compressor is cooled by another fluid, generally air, while remaining in the gas phase. This gas cooler thus plays the role of the condenser in a conventional air conditioning circuit where the refrigerant is present in two separate phases, one gas and the other liquid.

It will be recalled that, in an air conditioning circuit traversed by a refrigerant fluid in the supercritical state, this fluid remains essentially in the gaseous state and under a very high pressure which is usually between 100 and 150 bar. As a result, such heat exchangers, including their manifolds, must be able to withstand such high pressures, the burst pressure recommended is generally three times the value of the nominal operating pressure.

Collector boxes are already known which are designed to withstand such high pressures. These known collecting boxes usually comprise a tubular wall of section close to a circle, made either in a single portion, or in two parts, for collecting a fluid that flows in tubes whose ends are received in openings formed through the tubular wall. It can be either an electro-welded round box or a box formed of two parts or shells assembled together by crimping.

These known manifolds, however, have disadvantages.

Thus, the one-piece type manifolds require a puncture of the tubular wall for the realization of the passage openings of the tubes. However, the feasibility and accuracy of such openings are not demonstrated for small diameter and thick manifolds designed to withstand high pressures.

A collector box in two parts makes it possible to solve this difficulty, but these two parts must then be pre-assembled to allow a temporary mechanical resistance during brazing, this maintenance being then achieved by crimping, local deformation or by welding points.

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

It proposes for this purpose a manifold for heat exchanger, of the type comprising a tubular wall in which are arranged openings for the insertion of heat exchange tubes.

According to the invention, the manifold comprises two half-tubes of generally identical profiles having a wall having assembly edges provided with complementary assembly forms, one of the two half-tubes being provided with said openings. Thus, the manifold is made by assembling two half-tubes of respective profiles generally identical through complementary forms of assembly provided on respective assembly edges of the half-tubes.

As a result, the manifold is obtained simply by interlocking each time by making two pairs of complementary assembly shapes cooperate, the interlocking being similar to a clipping or clipping. The manufacture of the two half-tubes and their assembly can thus be carried out in very simple conditions.

The complementary assembly forms are advantageously of the male / female type.

In a preferred embodiment of the invention, the two half-tubes each have a male assembly shape and a female assembly shape. As a result, the two half-tubes can be made from the same basic profile, the difference being that one of the two half-tubes must then undergo an additional operation for the realization of the insertion openings of the tubes. heat exchange.

In another embodiment of the invention, one of the two half-tubes has two forms of male assembly, while the other of the two half-tubes has two forms of female assembly. In this case, the two half-tubes are made from different basic profiles.

According to an advantageous characteristic of the invention, the complementary assembly forms are arranged to cooperate by interlocking in force of the clip type. This solution ensures an effective provisional maintenance of the two half-tubes before their final assembly by soldering. In this case, it is advantageous that one of the forms of assembly is a form of male assembly which has a semicircular profile attached to the assembly edge by a narrower part and that the other form of assembly is a form of female assembly which has a complementary profile. In other words, the male assembly form must have a substantially arcuate profile extending over more than half a circumference.

Preferably, the assembly edges of each half-tubes have coplanar surfaces from which the forms of assembly are made. This allows for symmetrical shapes.

In the invention, the two half-tubes are advantageously obtained each by extrusion of a metallic material, in particular an aluminum alloy. It will thus be noted that the invention is different from that of document US Pat. No. 5,366,008 in which the tubes as well as the complementary assembly means are obtained by stamping.

The invention offers the additional advantage of being able to make the insertion openings with two different orientations.

In one embodiment, the insertion openings are oblong in shape and have their greatest length directed in the axial direction of the manifold.

In another embodiment, the insertion openings are oblong in shape and have their greatest length directed in the transverse direction of the manifold.

The insertion openings are advantageously made by machining. In another aspect, the invention relates to a method of manufacturing a header as defined above, which comprises the following operations:

a) preparing two half-tubes of generally identical profile having assembly edges provided with complementary assembly forms;

b) making insertion openings in one of the half-tubes; and

c) assembling the two half-tubes by cooperation of their assembly forms to thereby obtain a collector box with tubular wall.

Preferably, step a) comprises the preparation of an extruded base profile, having a male assembly shape and a female assembly shape, suitable for the preparation of each of the half-tubes.

In another aspect, the invention relates to a heat exchanger comprising a bundle of tubes and at least one collector box as defined above or can be obtained by the method defined above.

In a preferred application, this heat exchanger is made in the form of a gas cooler for an air-conditioning circuit traversed by a high-pressure refrigerant fluid operating in the supercritical state, as is the case with carbon dioxide. carbon (CO ₂ ).

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

- Figure 1 is a partial exploded perspective view of a manifold composed of two half-tubes in a first embodiment of the invention; FIG. 2 is a sectional view of one of the two half-tubes of the manifold of FIG. 1, namely that which comprises insertion openings;

FIG. 3 is a cross-sectional view of the other of the two half-tubes of the manifold of FIG. 1;

FIG. 4 is an enlarged detail view of FIG. 2 showing a male assembly profile;

FIG. 5 is an enlarged detail view of FIG. 2 showing a female assembly profile;

FIG. 6 is a partial top view of a header box in another embodiment of the invention, in which the insertion openings are transversely directed;

- Figure 7 is an enlarged sectional view along the line VII-VII of Figure 6, showing the half-tube having insertion openings;

- Figure 8 is a sectional view of a half-tube according to another embodiment of the invention;

- Figure 9 is a sectional view of a half-tube adapted to cooperate with the half-tube of Figure 8;

Figure 10 is a schematic partial view of a heat exchanger with two manifolds according to the invention; and

- Figure 11 is a schematic view of another heat exchanger comprising two manifolds according to the invention.

Referring first to FIG. 1, there is shown a heat exchanger header box 10 obtained by the assembly of a first half-tube 12 and a second half-tube 14 of respective generally identical profiles, the half-tubes 12 and 14 can, in this embodiment, be obtained from the same profile basic. The half-tubes 12 and 14 have respective walls 16, 18 of substantially semicircular section having assembly edges 20 and 22 for the half-tube 12 and 24 and 26 for the half-tube 14.

The walls 16 and 18 are generally thick and have respective bulges 28 and 30. In the bulge 28 of the wall 16, which forms a local extra thickness, are provided openings 32 of oblong shape for the insertion of exchange tubes. heat (not shown). These openings have an oblong shape and have their greatest length directed in the axial direction of the manifold, that is to say in a direction parallel to the generatrices of the latter.

The assembly edges 20 and 22 of the half-tube 12 are generally coplanar and extend in a substantially diametrical plane. They are provided with complementary forms of assembly, namely respectively a form of male assembly 34 and a form of female assembly 36.

Correspondingly, the assembly edges 24 and 26 of the half-tube 14 are generally coplanar and extend in a substantially diametrical plane. They are provided with a form of male assembly 34 and a female assembly form 36. These forms of assembly are complementary and can fit by shape cooperation. In the example, the half-tubes 12 and 14 are obtained from the same basic section.

On the section of Figure 2 we see one of the openings 32 in the direction of its smaller width. On the section of Figure 3, we see the section of the Half tube 14. It is understood that by bringing the half-tubes 12 and 14 closer, their respective assembly forms can be made to cooperate in order to obtain a tubular wall.

As seen more particularly in Figure 4, the male assembly form 34 has a semicircular profile defined by a surface 38 whose section extends over more than half a circumference. This surface 38 is attached by a narrower portion 40 to the joining edge 20 which has a coplanar surface with that of the assembly edge 22, these two surfaces extending in a plane passing through the center of the tubular wall, c. that is to say in a diametrical plane. The female assembly form 36 (FIG. 5) has a complementary profile.

Thus, the assembly of the half-tubes 12 and 14 is effected by interlocking in force, similar to a clipping or snapping, by cooperation of two pairs of male and female forms.

The half-tubes 12 and 14 are made, in this example, from the same base profile that can be obtained by extrusion and is advantageously made of aluminum-based alloy. This identical embodiment of the half-tubes 1 and 14 from the same profile makes it possible to standardize the manufacture and assembly of the manifolds, while ensuring the maintenance of said parts 12, 14 until soldering. This extrusion profile is produced in great length and is then cut into half tubes of selected length. Some of these half-tubes will then be pierced, by machining, to define insertion openings 32. As can be seen in FIGS. 1 and 2, the openings 32 comprise, over their entire periphery, an inlet chamfer 42 facilitating insertion and centering of the heat exchange tubes.

Referring now to FIG. 6 which shows another similar manifold, in which the half-tube 12 has openings 44, also of oblong shape, but the long length extends transversely to the axial direction of the manifold.

FIG. 7 shows that the half-tube 12 has a generally identical profile to that of FIG. 2, and comprises forms of male and female assembly 36. The half-tube 12 of FIG. 7 can therefore be assembled with a half-tube 14 similar to that of FIG.

FIG. 8 shows a variant which is similar to that of FIG. 2. The difference lies in the fact that the assembly edges 20 and 22 are each provided with a form of male assembly 34.

Correspondingly, the half-tube 14 shown in Figure 9 has female assembly shapes 36 on its two assembly edges 24 and 26. As a result, in this case, the half-tubes 12 and 14 do not are not made from the same basic profile.

Of course, the half-tube 12 which here comprises openings 32 could also include openings similar to the openings 44 of Figure 6, that is to say, oriented differently.

Also, in an alternative embodiment, the half-tube 12 could be provided with two female assembly shapes 36 and the half-tube 14 could be provided with two forms of male assembly 34.

Reference is now made to FIG. 10 which shows a heat exchanger 50 comprising a bundle composed of parallel tubes 52 between which corrugated dividers 54 are provided. This beam extends between two manifolds 10 according to the invention. In the example shown, the half-tube 12 of each manifold comprises openings 32 directed into the axial direction. As a result, the respective ends 56 of the tubes must be twisted, that is to say turned 90 °.

In the embodiment of FIG. 11, the half-tubes 12 of the two manifolds 10 have openings 44 extending in the transverse direction. As a result, the ends 56 of the tubes 52 do not need to be twisted as in the previous embodiment.

Such a heat exchanger can advantageously be made in the form of a gas cooler for an air conditioning circuit traversed by a high pressure refrigerant fluid operating in the supercritical state, as is the case of carbon dioxide (CO ₂ ). In such a gas cooler, the refrigerant fluid from a compressor is cooled by heat exchange with another fluid that scans the tube bundle. This other fluid is usually air. The gas cooler replaces the conventional condenser used in conventional air conditioning circuits where the refrigerant operates in two different phases.

The manufacture of a collecting box according to the invention essentially comprises the following three operations:

a) preparing the two half-tubes 12 and 14 of generally identical profile having assembly edges provided with complementary form of the male / female type;

b) make insertion openings 32 or 44 in one of the two half-tubes, here the half-tube 12; and

c) assembling the two half-tubes 12 and 14 by cooperation of their assembly forms to thereby form a collector box with tubular wall. In the preferred embodiment of the invention, step a) comprises the preparation of an extruded base profile, having a male assembly shape and a female assembly shape, suitable for the preparation of each half-tubes.

The manifold is then finally assembled by brazing. In the case of a heat exchanger as shown in Figure 10 or Figure 11, it is advantageous to assemble all components in a single operation by passing through a brazing furnace.

The manifold according to the invention is capable of numerous variants, in particular as regards its shape and dimensions. It will be understood that in the case where the manifold must receive a coolant under very high pressure, the thickness of the wall will be chosen to have sufficient strength.

Claims

claims

1. Heat exchanger collector box, comprising a tubular wall in which openings (32; 44) are provided for the insertion of heat exchange tubes (52),

characterized in that it comprises two half-tubes (12, 14) of generally identical profiles having a wall (16, 18) having assembly edges (20, 22; 24, 26) provided with complementary assembly shapes (34, 36), one of the half-tubes being provided with said openings (32; 44).

2. header box according to claim 1, characterized in that the two half-tubes (12, 14) each have a male assembly shape (34) and a female assembly shape (36).

3. collector box according to claim 1, characterized in that one of the two half-tubes (12, 14) has two forms of male assembly (34), while the other of the half-tubes has two forms of female assembly (36).

4. collector box according to one of claims 1 to 3, characterized in that the assembly forms (34, 36) are arranged to cooperate by a snap-in force of the clip type.

5. A collector box according to claim 4, characterized in that one of the forms of assembly is a form of male assembly (34) which has a semicircular profile attached to the assembly edge by a narrower part ( 40) and that the other of the forms of assembly is a form of female assembly (36) which has a complementary profile.

Container according to one of Claims 1 to 5, characterized in that the connecting edges (20, 22; 24, 26) of each half-tube (12, 14) have coplanar surfaces from which they are realized the forms of assembly (34, 36).

7. collector box according to one of claims 1 to 6, characterized in that the two half-tubes (12, 14) are each obtained by extrusion of a metal material.

8. header box according to one of claims 1 to 7, characterized in that the insertion openings (32) are oblong in shape and have their greatest length directed in the axial direction of the manifold (10).

9. header box according to one of claims 1 to 7, characterized in that the insertion openings (44) are oblong in shape and have their greatest length directed in the transverse direction of the manifold (10).

Container according to one of claims 1 to 9, characterized in that the insertion openings (32; 44) are machined.

11. A method of manufacturing a manifold for a heat exchanger according to one of claims 1 to 10, characterized in that it comprises the following operations: a) preparing two half-tubes (12, 14) of profiles generally identical with assembly edges

(20, 22; 24, 26) provided with complementary assembly shapes (34, 36);

b) making insertion openings (32; 44) in one of the half-tubes; and c) assembling the two half-tubes (12, 14) by cooperation of their assembly forms to thereby form a collector box (10) with tubular wall.

A method according to claim 11, characterized in that step a) comprises preparing an extruded base profile having a male assembly shape (34) and a female assembly shape (36). , suitable for the preparation of each of the half-tubes.

13. Heat exchanger comprising a tube bundle (52) and at least one header box (10) according to one of claims 1 to 10 or obtainable by a method according to one of claims 11 and 12.

14. Heat exchanger according to claim 13, characterized in that it is in the form of a gas cooler for an air conditioning circuit traversed by a high pressure refrigerant fluid operating in the supercritical state.