US20160377357A1

US20160377357A1 - Collection box and corresponding heat exchanger

Info

Publication number: US20160377357A1
Application number: US15/104,035
Authority: US
Inventors: Christian Riondet; Jean-Marc Lesueur
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2013-12-13
Filing date: 2014-10-14
Publication date: 2016-12-29
Also published as: EP3080542A1; JP2018189363A; WO2015086195A1; CN106461353A; KR20160098413A; JP2022048152A; FR3015016A1; EP3080542B1; JP7383687B2; FR3015016B1; JP2020128865A; JP2017500528A; CN106461353B

Abstract

The invention relates to a collection box (1) for a heat exchanger comprising a header (5) having an at least partially rounded shape and comprising:

- a plurality of openings (7) for the passage of a plurality of heat-exchange tubes (3) of the heat exchanger, and
- a plurality of flanges (9) surrounding the openings (7).

According to the invention, the header (5) comprises a plurality of corrugations (11), and the flanges (9) are created at the corrugations (11) of the header (5) and respectively have a substantially flared shape directed away from the volume defined by the collection box (1).

Description

The invention relates to a collection box for a heat exchanger, particularly for a motor vehicle. The invention also relates to a corresponding heat exchanger. Such a heat exchanger is, for example, used in a motor vehicle, notably as a radiator for the cooling system, or in high-pressure applications, for example as a condenser for an air conditioning system.
In general, such a heat exchanger comprises a core bundle of tubes and at least one collection box. This collection box is configured to accept the ends of the tubes of the heat exchanger.
For that purpose, the collection box generally comprises a header, for example in the form of a header plate. The collection box generally also comprises a cover that fixes to the header plate to close the collection box.
The header plate allows the fluid to be distributed to the heat exchange tubes or allows the fluid from these heat exchange tubes to be collected. The header plate is generally made of aluminum and may for example be produced by stamping.
The header plate generally has a flat bottom.
However, in applications intended to withstand pressure, it is known practice for the header to have an at least partially rounded bottom in order to withstand the pressure. Moreover, the flat-bottomed or dished-bottomed header plate is usually provided with flanges surrounding openings through which the ends of the tubes of the core bundle of the heat exchanger pass.
The openings such as slots are made in the header plate for the introduction of the tubes, for example with a removal of material or, on the other hand, without removing material. In the latter case, the material is pushed by the tooling towards the inside of the volume defined by the collection box, thus creating a flange around the opening for the introduction of the tube. These are referred to as standard flanges.
The flanges make it possible to ensure contact between the tube and the opening in the header plate and to obtain high-quality brazing in the case of brazed, for example all-aluminum, exchangers.
The tubes are generally inserted into the opening in the same direction as the tooling used to create the flanges around the openings. The inserted tubes generally extend partially into the collection box in order to guarantee correct brazing and firm and leaktight assembly. With certain solutions, the tubes protrude into the volume forming a reservoir for the fluid by almost half the volume of the collection box.
However, having the tubes protruding into the volume defined by the interior volume of the collection box that forms a reservoir for the fluid creates an internal pressure drop in the fluid circuit. This internal pressure drop entails increasing the pumping power in order to maintain a certain fluid flow rate.
According to a known solution, a flat-bottomed collection box may have flanges referred to as reverse flanges which means to say flanges produced in the opposite direction to the direction of insertion of a heat-exchange tube. The flanges than have a flared shape facing away from the volume defined by the collection box. However, such reverse flanges are only very slightly flared, which in other words means that the known reverse flanges define a small entry cone for the insertion of the heat-exchange tubes. The entry cone may therefore not be enough to allow the heat-exchange tubes to be inserted simply, and the solutions known from the prior art may present difficulties with inserting the heat-exchange tubes into the header.
Because of this difficulty of inserting the heat-exchange tubes into the header that has such reverse flanges, such a reverse-flanges solution for a round-bottomed header is not envisioned in the prior art where so-called standard flanges take preference.
It is an objective of the invention to propose a collection box that allows these problems of the prior art to be solved.
To this end, one subject of the invention is a collection box for a heat exchanger comprising a header having an at least partially rounded shape and comprising a plurality of openings for the passage of a plurality of heat-exchange tubes of the heat exchanger, and a plurality of flanges surrounding the openings, characterized in that the header further comprises a plurality of corrugations, and in that the flanges are created at the corrugations of the header and respectively have a substantially flared shape directed away from the volume defined by the collection box.
According to one preferred embodiment, the flanges are formed at the crests of the corrugations facing away from the volume defined by the collection box.
Such an at least partially rounded box is suited to withstanding pressure in high-pressure applications, and the header with such reverse flanges, namely flanges facing in the opposite direction to the usual direction of insertion of the tubes, is able to accept the ends of the tubes which, previously, would have projected into the volume defined by the collection box.
The ends of the tubes therefore no longer open into the volume defined by the collection box. This results in a significant reduction in the pressure drop associated with the flow of a fluid through the tubes of the heat exchanger.
In conclusion, by combining an at least partially rounded header with a plurality of corrugations there is enough material to form reverse flanges that are flared enough to facilitate the introduction of the heat-exchange tubes. Specifically, the reverse flanges according to the invention define a substantially tulip-shaped inlet opening for the insertion of the heat exchange tubes that is wide enough because of this addition of material.
Said collection box may further comprise one or more of the following features considered separately or in combination:

- the header has at least one wall, the shape of which is substantially dished towards the outside of the volume defined by the collection box,
- the corrugations are formed on the wall,
- the corrugations respectively have a top height of the order of 30% of the pitch of the tube, this height being sufficient to form a flange,
- the flanges respectively have a substantially conical shape,
- a cone formed by a flange has an angle of the order of 30°, making it easier at the same time for the plurality of heat-exchange tubes to be introduced into the header openings surrounded by the flanges,
- the flanges respectively have a first width and a second width greater than the first width, for example of the order of twice the first width, thus offering an opening that is wide enough to facilitate introduction of all the heat exchange tubes into the openings in the header,
- the first width is substantially equal to the width of a tube intended to be inserted in the opening,
- the flanges respectively have two convex substantially flared edges with the convexity facing toward the outside of the volume defined by the collection box,
- the flanges have a height of the order of half the height of a corrugation,
- the flanges are thinned with respect to the corrugations on the header so that the corrugations respectively have a first thickness and the flanges respectively have a second thickness smaller than the first thickness of the corrugation,
- the thinning of the material at a flange is at least greater than 30% of the initial thickness of the material, or even locally greater than 50% of the initial thickness of the material. By thinning the material the flanges can be lengthened in order to obtain enough of a flare to facilitate the introduction of the tubes.

The invention also relates to a heat exchanger, particularly for motor vehicles, comprising a heat-exchange core bundle of tubes, the ends of which are fixed to at least one collection box, as defined hereinabove.
This may be a brazed heat exchanger.
As an alternative, it may be a heat exchanger of which the elements that form the collection box are mechanically assembled to one another.
According to one embodiment, the heat-exchange tubes have a height comprised between 0.8 mm et 2.5 mm, preferably between 1.2 mm and 1.8 mm.
The pitch of the heat-exchange tubes, which means to say the center-distance between two heat-exchange tubes, is, for example, comprised between 5 mm and 10 mm, preferably between 6 mm and 8 mm.

Further features and advantages of the invention will become more clearly apparent from reading the following description, given by way of illustrative nonlimiting example, and from studying the attached drawings among which:

FIG. 1 is a perspective view of a collection box according to the invention for a heat exchanger,

FIG. 2 is a partial view in cross section of the collection box of FIG. 1 accepting an end of a partially depicted tube of a core bundle of tubes of the heat exchanger,

FIG. 3 is a side view in cross section of the header of FIG. 1,

FIG. 4a is a first perspective view of a header of the collection box of FIGS. 1 to 3,

FIG. 4b is a second perspective view of the header of the collection box of FIGS. 1 to 3,

FIG. 5 is a view in transverse section of the header of FIGS. 4a and 4 b, and

FIG. 6 is an enlarged view of the header of FIG. 5 accepting ends of tubes of the heat exchanger.

In these figures, elements that are identical bear the same references.
FIG. 1 schematically and in simplified form depicts a fluid collection box 1 for a heat exchanger (not depicted), notably in the automotive field. The heat exchanger may be used in particular as a radiator or as a condenser for a motor vehicle.
In particular, the invention may be applied to a brazed heat exchanger.
The heat exchanger comprises a core bundle of tubes 3. Only one end of one tube 3 is visible in FIG. 2. The tubes 3 are for example made of aluminum or aluminum alloy. They are, for example, substantially flattened tubes 3.
The collection box 1 is configured to accept at least one end of a tube 3 of the heat exchanger, more specifically to accept the ends of a multiplicity of tubes 3 of the heat exchanger (which is not illustrated). Only one end of one tube 3 is visible in FIG. 2.
The collection box 1 for this purpose comprises a header 5. The collection box 1 also comprises a cover 6 fixed to the header 5 so as to close the collection box 1.
The header 5 is, for example, made of aluminum or of aluminum alloy. The cover 6 for its part may be made of aluminum of aluminum alloy or, as an alternative, of plastic.
The cover 6 may be fixed to the header 5 for example by clip-fastening, by brazing or even by crimping.
Furthermore, the header 5 comprises a plurality of openings 7 for the passage of the ends of the tubes 3.
The openings 7 have, for example, a substantially elongate shape, like slots.
The ends of the tubes 3 accepted into the openings 7 may then be brazed for example to the header 5.
According to one embodiment, the heat exchange tubes 3 have a height comprised between 0.8 mm and 2.5 mm, preferably between 1.2 mm and 1.8 mm.
The pitch of the heat-exchange tubes 3, which means to say the center-distance between two heat-exchange tubes 3 is, for example, comprised between 5 mm and 10 mm, preferably between 6 mm and 8 mm.
According to the embodiment illustrated, the header 5 has a wall 8 forming a box end. The collection box 1 additionally comprises lateral walls 8′ connected to this box end 8.
This is a box end 8 of at least partially rounded shape.
According to the embodiment illustrated, the wall 8 forming the end of the box, also referred to as the end wall 8, has a shape that is substantially dished toward the outside of the volume defined by the collection box 1. Thus, the end wall 8 of the header 5 has a shape that is substantially concave with respect to the interior volume defined by the collection box 1 and substantially convex with respect to the core bundle of tubes 3 of the heat exchanger, with the convexity facing toward the outside of the volume defined by the collection box 1.
As visible in FIGS. 1 to 3, the collection box 1 additionally comprises a predefined number of flanges 9 formed on the header 5 at the openings 7 for accepting the ends of the tubes 3. More specifically, each opening 7 is surrounded by a flange 9. The flanges 9 are in this instance produced without the removal of material.
The header 5 additionally comprises a plurality of deformations 11. The deformations 11 are created at the substantially dished end wall 8 of the header 5. The deformations 11 are produced for example in such a way as to form a regular pattern.
According to the embodiment illustrated, this pattern is made up of corrugations or waves 11.
The corrugations 11 may be produced symmetrically with respect to the longitudinal axis of the end wall 8 of the header 5. The corrugations 11 therefore have crests extending alternating on one side and the other of the longitudinal axis of the end wall 8 of the header 5. In order words, the corrugations 11 have, for example, a plurality of crests facing towards the inside of the volume defined by the collection box 1 and a plurality of opposite crests directed away from the volume defined by the collection box and therefore toward the outside of the collection box 1 and toward the core bundle of tubes 3 of the heat exchanger.
The flanges 9, better visible in FIGS. 4a and 4 b, are formed at the corrugations 11, more specifically at the crests of the corrugations 11 facing away from the volume defined by the collection box. In particular, the openings 7 are formed by piercing or perforating the header 5 at the crests of the corrugations 11 facing away from the volume defined by the collection box, and the flanges 9 are produced by the material around these openings 7.
In order to be able to have enough material from which to form the flanges 9 at the corrugations 11, the corrugations 11 are created with a sufficient height h (cf FIG. 5), for example with a top height h of the order of 30% of the pitch of the tubes.
The flanges 9 thus formed face away from the volume defined by the collection box 1, namely toward the core bundle of tubes 3 of the heat exchanger. They are then referred to as reverse flanges 9.
Thus, and referring once again to FIG. 2 and to FIG. 6, when the end of a tube 3 of the heat exchanger is inserted into an opening 7 surrounded by such a reverse flange 9, this end of tube 3 lies in a zone Z situated between the crests of the corrugations 11 which face toward the inside of the volume defined by the collection box 1 and the level of the box end 8 of the header 5 but does not protrude into the volume defined by the collection box 1. The absence of tubes 3 opening into the volume of the collection box 1 makes it possible to improve performance in terms of fluid flow.
The flanges 9 have a sufficient height h′ suited to allowing the insertion of the ends of the tubes 3, for example of the order of half the height h of a corrugation 11.
Furthermore, the flanges 9 have a flared overall shape, such as a tulip shape.
More specifically, the flanges 9 respectively have a substantially conical shape, for example of angle α of the order of 30° (cf. FIG. 5).
A flange 9 therefore has two flared edges 9 a, 9 b, corresponding to the two long edges, joined together by two short edges 9 c, 9 d.
This flared or substantially conical shape facilitates the introduction of the ends of the tubes 3 into the header 5, from outside the volume defined by the collection box 1 toward the inside of the volume defined by the collection box 1.
The two flared edges 9 a, 9 b for example have a substantially convex shape with the convexity facing toward the outside of the volume defined by the collection box 1.
With reference to FIG. 5, the tulip-shaped flanges 9 respectively have:

- a first width l₁at the pierced or perforated crest of the associated corrugation 11 which corresponds to the shortest width of the flange 9, and
- a peripheral second width l₂which corresponds to the greatest width of the flange 9.

The first width l₁is substantially equal to or slightly greater than the width of a tube 3 intended to be inserted into the opening 7.
The greatest width l₂defines the opening 7 surrounded by the flange 9 for the insertion of the end of a tube 3. The second width l₂is made wide enough to allow simple and, notably, simultaneous, insertion of the ends of all of the tubes 3 of the heat exchanger (which is not depicted) into the openings 7. The second width l₂is, for example, of the order of twice the first width l₁of the flange 9.
Furthermore, the flanges 9 may be thinned with respect to the corrugations 11 on the header 5. Specifically, with reference to FIG. 6, a corrugation 11 has, for example, a first thickness e₁, and the flange 9 has a second thickness e₂less than the first thickness e₁of the corrugation 11.
The flange 9 may just as easily be thinned at the long flared edges 9 a, 9 b as at the short connecting edges 9 c and 9 d.
By way of example, the thinning of material is performed at the flange 9 and may range beyond 30% or even locally beyond 50% of the initial thickness of the material.
By thinning the material at a flange 9, this flange 9 may be lengthened.
It will therefore be appreciated that a header 5 comprising such reverse flanges 9 facilitates the introduction of the ends of the multiplicity of heat exchange tubes 3 of the heat exchanger simultaneously and simply without requiring any special-purpose tooling notably to guide each tube 3 into the associated opening 7.
Specifically, the reverse and flared flanges 9 offer enough of an opening for introduction from outside the collection box 1 toward the inside of the volume defined by the collection box 1.
Finally, these reverse flanges 9 allow the insertion of the ends of the tubes 3 without these ends opening into the volume defined by the collection box 1, thus encouraging the flow of the fluid inside the collection box 1.

Claims

1. A collection box for a heat exchanger comprising a header having an at least partially rounded shape, the header comprising:

a plurality of openings for the passage of a plurality of heat-exchange tubes of the heat exchanger; and

a plurality of flanges surrounding the openings; and

a plurality of corrugations, wherein the flanges are created at the corrugations of the header and respectively have a substantially flared shape directed away from the volume defined by the collection box.

2. The collection box as claimed in claim 1, in which the flanges are formed at the crests of the corrugations facing away from the volume defined by the collection box.

3. The collection box as claimed in claim 1, in which the header has at least one wall, the shape of which is substantially dished towards the outside of the volume defined by the collection box.

4. The collection box as claimed in claim 3, in which the corrugations are formed on the wall.

5. The collection box as claimed in claim 1, in which the corrugations respectively have a top height of the order of 30% of the pitch of the tubes.

6. The collection box as claimed in claim 1, in which the flanges respectively have a substantially conical shape.

7. The collection box as claimed in claim 6, in which a cone formed by a flange has an angle of the order of 30°.

8. The collection box as claimed in claim 1, in which the flanges respectively have:

a first width ; and

a second width two times greater than the first width.

9. The collection box as claimed in claim 8, in which the first width is substantially equal to the width of a tube intended to be inserted in the opening.

10. The collection box as claimed in claim 1, in which the flanges respectively have two convex substantially flared edges with the convexity facing toward the outside of the volume defined by the collection box.

11. The collection box as claimed in claim 1, in which the flanges have a height of the order of half the height of a corrugation.

12. The collection box as claimed in claim 1, in which the flanges are thinned with respect to the corrugations on the header.

13. The collection box as claimed in claim 12, in which the thinning of the material at a flange is at least greater than 30% of the initial thickness of the material.

14. A heat exchanger for a motor vehicle, comprising a heat-exchange core bundle of tubes, the ends of which are fixed to at least one collection box in accordance with claim 1.

15. The heat exchanger as claimed in claim 14, in which the heat-exchange tubes have a height comprised between 1.2 mm and 1.8 mm.

16. The heat exchanger as claimed in claim 14, in which the pitch of the heat-exchange tubes is comprised between 6 mm and 8 mm.