Patent Application
20160377357
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 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:
In these figures, elements that are identical bear the same references.
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
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
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
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
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
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
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.
A flange 9 therefore has two flared edges 9a, 9b, corresponding to the two long edges, joined together by two short edges 9c, 9d.
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 9a, 9b 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
The first width l1 is substantially equal to or slightly greater than the width of a tube 3 intended to be inserted into the opening 7.
The greatest width l2 defines the opening 7 surrounded by the flange 9 for the insertion of the end of a tube 3. The second width l2 is 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 l2 is, for example, of the order of twice the first width l1 of the flange 9.
Furthermore, the flanges 9 may be thinned with respect to the corrugations 11 on the header 5. Specifically, with reference to
The flange 9 may just as easily be thinned at the long flared edges 9a, 9b as at the short connecting edges 9c and 9d.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1362571 | Dec 2013 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/071941 | 10/14/2014 | WO | 00 |
