EP3394554B1 - Heat exchanger, in particular for a motor vehicle - Google Patents

Description

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 particular, the invention relates to a heat exchanger corresponding to the preamble of claim 1, and as disclosed by the document FR 2 912 811 .

In this regard, the invention relates more particularly to heat exchangers capable of being traversed by a refrigerant fluid having a relatively high operating pressure, as is the case with natural gases such as carbon dioxide designated by CO ₂ , having an operating pressure higher than the refrigerant gases used in the solutions of the state of the art.

Such heat exchangers find particular application in motor vehicles. They can in particular constitute a gas cooler in which the refrigerant fluid such as CO ₂ is cooled by a second fluid, such as liquid. Conversely, the second fluid can be cooled by the first fluid, for example in gaseous form, the heat exchanger is then commonly designated by “Water chiller” in English.

Such heat exchangers can in particular be used in the thermal regulation of one or more batteries of an electric or hybrid vehicle. The thermal regulation of the batteries is an important point because if the batteries are subjected to temperatures that are too cold, their autonomy can decrease sharply and if they are subjected to too high temperatures, there is a risk of thermal runaway which can go up to destruction of the battery, or even of the motor vehicle. In order to regulate the temperature of the batteries, it is known to use a heat transfer fluid, in general cooling liquid comprising a mixture of glycol water, which circulates within a heat exchanger in contact with the battery or batteries. The coolant can thus bring heat to the battery or batteries to heat them, this heat having been absorbed by the coolant for example during the heat exchange with the CO ₂ circulating in the gas cooler. The coolant can also, if necessary, absorb heat emitted by the battery or batteries in order to cool them and evacuate this heat at the level of one or more other heat exchangers.

Such heat exchangers can also be used like any other gas cooler in an air conditioning circuit.

These heat exchangers can in particular be heat exchangers assembled by brazing.

Heat exchangers are known, for example, comprising a stack of plates allowing the circulation of the first fluid, such as the refrigerant or refrigerant gas, and of the second fluid such as the coolant.

However, the use of a coolant such as CO ₂ under a very high pressure, generally greater than 100 bars, with a burst pressure which can reach for example up to 340 bars, implies that the heat exchangers such as gas coolers, must withstand such high pressures.

The plate heat exchangers known from the prior art do not make it possible to withstand such high pressures.

To remedy this, heat exchangers are also known from the prior art, comprising a stack of tubes connected together by at least one collector of the first fluid, in particular the refrigerant on each side of the tubes, and the second fluid, for example. in liquid form, can circulate around the tubes in an envelope connected to a water box.

However, such an architecture is complex to produce and in particular has drawbacks in terms of sealing, in particular in the case of a brazed heat exchanger for which it turns out to be necessary to provide multiple brazing points for several parts of the heat exchanger. In addition, with this architecture, the two fluids generally circulate in cross flow. It is not always possible to provide a circulation against the current or in several passes of the two fluids, which limits the efficiency of the heat exchanger. In addition, it proves difficult to reduce the tube height below 2mm due to the known design of the manifold receiving the ends of the tubes, which also limits the efficiency of the heat exchanger. It has also been found that such a heat exchanger does not always have good mechanical strength. In addition, it is difficult to reduce the tube height below 2mm due to the design known to the manifold receiving the ends of the tubes, which also limits the efficiency of the heat exchanger. It has also been found that such a heat exchanger does not always have good mechanical strength.

Furthermore, a constant problem of heat exchangers implemented in a motor vehicle lies in the allocation of a reduced space, in order to meet the requirements of manufacturers.

The present invention aims to improve the solutions of the state of the art and to at least partially resolve the drawbacks set out above by proposing a heat exchanger which is simple to produce and which has a reduced bulk while at the same time having advantageous properties in order to resist at best strong local pressures.

• le faisceau d'échange thermique comprend une pluralité de premiers cadres de réception des tubes d'échange thermique, et
• les premiers cadres de réception des tubes d'échange thermique comprennent respectivement au moins une zone d'absorption de contraintes, agencée sur au moins un bord en vis-à-vis d'une extrémité d'un tube d'échange thermique et apte à résister aux contraintes mécaniques.

To this end, the subject of the invention is a heat exchanger, in particular for a motor vehicle, said exchanger comprising a heat exchange bundle with a plurality of heat exchange tubes defining circulation channels for a fluid. According to the invention:

• the heat exchange bundle comprises a plurality of first frames for receiving the heat exchange tubes, and
• the first frames for receiving the heat exchange tubes respectively comprise at least one stress absorption zone, arranged on at least one edge facing an end of a heat exchange tube and capable of resist mechanical stress.

Such a heat exchanger has better mechanical strength compared to the solutions of the prior art and very good resistance to high pressures, in particular due to the circulation of CO ₂ as refrigerant.

In the invention, the frames designate a part, or an assembly of parts, which can be rigid, delimiting a closed or not space. In this space can be positioned, in our example, heat exchange tubes.

It will be noted that the heat exchange bundle, which comprises a plurality of heat exchange tubes, is distinct from the frames.

• les zones d'absorption de contraintes sont réalisées par un nombre prédéterminé de jambes d'absorption de contraintes formées sur au moins un bord d'un premier cadre de réception en vis-à-vis d'une extrémité d'un tube d'échange thermique et s'étendant en direction de l'extrémité du tube d'échange thermique ;
• les jambes d'absorption de contraintes s'étendent longitudinalement sensiblement parallèlement à la direction d'écoulement du fluide dans les canaux de circulation ;
• les premiers cadres présentent une pluralité d'évidements, et deux jambes d'absorption de contrainte adjacentes s'étendent de part et d'autre d'un évidement ;
• les premiers cadres présentent respectivement au moins un bord en vis-à-vis d'une extrémité d'un tube d'échange thermique conformé selon un motif définissant une succession d'arches, les pieds d'arches formant les jambes d'absorption de contraintes ;
• l'échangeur thermique comprend au moins une boîte collectrice du fluide, et lorsque des tubes d'échange thermique sont reçus dans les premiers cadres, les voûtes des arches définissent avec les extrémités des tubes d'échange thermique des ouvertures de mise en communication fluidique entre la boite collectrice et les tubes d'échange thermique, de sorte qu'une ouverture de mise en communication fluidique est agencée entre deux pieds d'arche ;
• l'échangeur thermique est assemblé par brasage et les jambes d'absorption de contraintes définissent des zones de brasage.

The heat exchanger may also include one or more of the following characteristics, taken alone or in combination:

• the stress absorption zones are produced by a predetermined number of stress absorption legs formed on at least one edge of a first receiving frame facing an end of an exchange tube thermal and extending towards the end of the heat exchange tube;
• the stress absorbing legs extend longitudinally substantially parallel to the direction of flow of the fluid in the circulation channels;
• the first frames have a plurality of recesses, and two adjacent stress absorption legs extend on either side of a recess;
• the first frames respectively have at least one edge vis-à-vis one end of a heat exchange tube shaped according to a pattern defining a succession of arches, the arches feet forming the absorption legs of constraints;
• the heat exchanger comprises at least one fluid collecting box, and when heat exchange tubes are received in the first frames, the arches of the arches define with the ends of the heat exchange tubes openings for fluid communication the manifold and the heat exchange tubes, so that a fluid communication opening is arranged between two arch feet;
• the heat exchanger is assembled by brazing and the stress absorption legs define brazing zones.

According to another aspect of the invention, a first fluid is able to circulate in the heat exchange tubes, and the heat exchanger further comprises a plurality of second frames respectively arranged alternately with the first frames for receiving the tubes heat exchange, and respectively defining a second circulation channel for a second fluid so as to allow heat exchange between the first fluid and the second fluid.

The heat exchange tubes are received and maintained in first dedicated frames while the turbulators can be received in the second dedicated frames and thus be superimposed on the heat exchange tubes.

The heat exchanger thus comprises a stack of simple elements, namely frames and heat exchange tubes in which the first fluid circulates, such as the refrigerant gas, inserted in the first frames and between which the second fluid circulates. only coolant.

Such an architecture allows a simpler realization of the heat exchanger as a whole.

According to an additional aspect, the second frames have through passage orifices arranged in alignment with the recesses, so as to allow the flow of the first fluid in the stack of the first frames and of the second frames.

The superimposed frames make it possible to create the flow path for the first fluid, when the frames are assembled together, for example by brazing.

Likewise, the superimposed frames advantageously make it possible to create the flow path for the second fluid, in particular on two opposite sides of the heat exchange bundle.

• la figure 1 est une vue en perspective d'un échangeur thermique selon l'invention,
• la figure 2 est une vue en coupe de dessous de l'échangeur thermique de la figure 1,
• la figure 3 est une vue partielle en perspective d'un empilement de premiers cadres et de deuxièmes cadres du faisceau d'échange thermique de l'échangeur thermique de la figure 1,
• la figure 4 représente de façon schématique un premier cadre du faisceau d'échange thermique recevant deux tubes d'échange thermique,
• la figure 5 est une vue du premier cadre seul de la figure 4, et
• la figure 6 est une autre vue en perspective d'un empilement de premiers cadres et de deuxièmes cadres du faisceau d'échange thermique de l'échangeur thermique de la figure 1.

Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and nonlimiting example, and of the appended drawings among which:

• the figure 1 is a perspective view of a heat exchanger according to the invention,
• the figure 2 is a sectional view from below of the heat exchanger of the figure 1 ,
• the figure 3 is a partial perspective view of a stack of first frames and second frames of the heat exchange bundle of the heat exchanger of the figure 1 ,
• the figure 4 schematically represents a first frame of the beam heat exchange receiving two heat exchange tubes,
• the figure 5 is a view of the first frame alone of the figure 4 , and
• the figure 6 is another perspective view of a stack of first frames and second frames of the heat exchange bundle of the heat exchanger of the figure 1 .

In these figures, the substantially identical elements have the same references.

The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the characteristics apply only to a single embodiment. Simple features of different embodiments can also be combined to provide other embodiments.

In the present, the terms upper and lower, or top and bottom, or vertical and horizontal, are designated with reference to the arrangement of the elements in the figures. This arrangement corresponds to the reverse arrangement of the elements in the mounted state in a motor vehicle in particular.

Heat exchanger

With reference to the figure 1 , the invention relates to a heat exchanger 1 in particular for a motor vehicle, for a heat exchange between at least a first fluid and a second fluid.

The first fluid can enter the heat exchanger 1 in gaseous form and the second fluid in liquid form.

It is in particular a heat exchanger assembled by brazing. To do this, the heat exchanger 1 has at least partially, that is to say on at least some elements or certain parts, a coating intended to melt to ensure the joining of elements of the heat exchanger during the by brazing.

The coating is commonly designated by "clad" in the field of brazing of metal parts, in particular aluminum. In particular, the coating is added on the core of the parts, during manufacture, for example by cold rolling. It may be a non-limiting example of a coating comprising aluminum and silicon.

The heat exchanger 1 according to the invention is in particular suitable for the circulation of at least one fluid having a high operating pressure, in particular greater than 100 bars.

For example, the first fluid is a refrigerant intended to circulate at high pressure such as CO ₂ , also designated by R744 according to the industrial nomenclature.

The heat exchanger 1 can in particular be a gas cooler in which the refrigerant fluid such as CO ₂ is cooled by a second fluid, for example in liquid form, such as coolant comprising a mixture of glycol water.

The second fluid such as the coolant can also be cooled by the first fluid such as CO ₂ , such a heat exchanger is then commonly designated by "Water chiller" in English.

The heat exchanger 1 comprises a heat exchange bundle 3 allowing the heat exchange between the first fluid and the second fluid. In the example illustrated, the heat exchange bundle 3 has a generally substantially parallelepiped shape.

The circulation of the first and second fluids is advantageously done against the current in the heat exchange bundle 3.

The introduction and evacuation of the first fluid in the heat exchange bundle 3 or out of the heat exchange bundle 3 is shown schematically by way of example by the arrows F1 _I for the introduction and F1 _O for the evacuation .

Likewise, the introduction of the second fluid into the heat exchange bundle 3 and the evacuation of the second fluid out of the heat exchange bundle 3 is shown schematically by way of arrows F2 _I for the introduction and F2 _O for evacuation.

Finally, the heat exchanger 1, and more precisely the heat exchange bundle 3, can be configured for circulation in at least two passes of one of the two fluids, or even of the two fluids.

An example of circulation of the two fluids against the current and in two passes is illustrated schematically by the arrows F1 and F2 on the figure 1 .

More specifically, the heat exchange bundle 3 comprises a plurality of heat exchange tubes 5, visible on the figures 2 to 4 , stacked so as to alternately define first circulation channels (not visible in the figures) for the first fluid in the heat exchange tubes 5 and second circulation channels 9 for the second fluid between the heat exchange tubes 5 .

The heat exchange tubes 5 can be produced in the form of flat tubes, advantageous in terms of space.

The flat tubes 5 have a substantially rectangular general shape, with a length for example of the order of 32mm and a thickness of the order of a millimeter. The thickness is here considered in the direction of the height of the heat exchange bundle 3, we can also speak of the height of the heat exchange tubes 5. In other words, it is the thickness in the direction d stack of heat exchange tubes 5.

Each heat exchange tube 5 defines a predetermined number of first circulation channels (not visible in the figures) for the first fluid, in particular micro-circulation channels for the first fluid.

The first channels or micro-channels extend, for example, substantially longitudinally, in a substantially “I” or rectilinear shape. The first circulation channels or micro-channels for the first fluid allowing the flow of the first fluid extend respectively in a direction parallel to the longitudinal direction of the heat exchange tubes 5.

The first fluid can follow a circulation in a pass called “I” circulation but also a circulation in two passes called “U” circulation.

Likewise, the second circulation channels 9 for the second fluid can be shaped to allow circulation in a so-called "I" circulation pass but also a circulation in two passes called "U" circulation.

Turbulators 11 for the flow of the second fluid, for example shaped substantially in slots, are advantageously arranged in the second circulation channels 9, thus improving the heat exchange between the two fluids.

The turbulators 11 can be carried by an element 12 separate from the heat exchange tubes 5 as illustrated in the figures 2 and 3 .

As a variant, turbulators 11 can be formed on the heat exchange tubes 5, for example by deformations such as undulations of the heat exchange tubes 5 which project into the second circulation channels 9 for the second fluid.

Interleaves are advantageously arranged between the heat exchange tubes 5, and define the pitch between the heat exchange tubes 5.

According to one embodiment, the heat exchange bundle 3 comprises an alternating stack of first frames 13 and second frames 15.

At least some second frames 15 form the spacers. The stacking takes place here substantially vertically.

Each first frame 13 is capable of receiving at least one heat exchange tube 5 and this assembly forms a stage of the heat exchange bundle 3. The first frames 13 can be designated by tube frames.

Each second frame 15 can receive turbulators 11 and this assembly forms another stage of the heat exchange bundle 3. These two assemblies or stages are repeated as many times as necessary according to the space available and the performance to be achieved.

The first frames 13 and the second frames 15 are described in more detail below.

For example, closure plates 17, 18 (see figure 1 ), in particular at least one lower closure plate 17 and at least one upper closure plate 18, can be arranged on either side of the stack of first frames 13 and second frames 15, so as to close the heat exchange bundle 3. The closure plates 17, 18 have a shape complementary to the shape of the first frames 13 and of the second frames 15.

Referring to Figures 1 and 2 , the heat exchanger 1 further comprises at at least one manifold 19 of the first fluid arranged in fluid communication with the first circulation channels (not visible in the figures) defined in the heat exchange tubes 5.

The manifold 19 is, according to the example illustrated, arranged on an upper closure plate 18 disposed at the top of the heat exchange bundle 3.

The heat exchanger 1 also comprises at least two fluid inlet and outlet pipes 21 allowing the introduction and the evacuation of the second fluid. In this example, the two pipes 21 are arranged on the same upper closure plate 18 as the manifold 19 for the first fluid.

Of course, according to a variant not illustrated, provision can be made to arrange the two pipes 21 on the lower plate 17.

According to yet another variant, not illustrated, provision may be made for the pipes 21 to be arranged separately, with one pipe 21 on the upper plate 18 and the other pipe 21 on the lower plate 17.

In particular, the manifold 19 can be arranged on one side of the heat exchange bundle 3 and the pipes 21 can be arranged on the other side of the heat exchange bundle 3, thus allowing counter-current circulation of the two fluids.

According to the arrangement illustrated on the Figures 1 and 2 , the manifold 19 is arranged on the left while the pipes 21 are arranged on the right.

First frames called tube frames

With reference to figures 2 to 5 , the first frames 13 for receiving the heat exchange tubes 5 will now be described in more detail.

The first frames 13 can be at least partially made of aluminum.

• deux bords opposés 13A, 13B (voir figures 4 et 5) s'étendant de façon perpendiculaire à la direction des premiers canaux (non représentés) de circulation du premier fluide dans les tubes d'échange thermique 5, autrement dit ici perpendiculairement à la direction longitudinale des tubes d'échange thermique 5, et
• deux autres bords opposés 13C, 13D s'étendant parallèlement à la direction des premiers canaux (non représentés) de circulation du premier fluide dans les tubes d'échange thermique 5, autrement dit ici parallèlement à la direction longitudinale des tubes d'échange thermique 5.

The first frames 13 present:

• two opposite edges 13A, 13B (see Figures 4 and 5 ) extending perpendicular to the direction of the first channels (not shown) for circulation of the first fluid in the heat exchange tubes 5, in other words here perpendicular to the longitudinal direction of the heat exchange tubes 5, and
• two other opposite edges 13C, 13D extending parallel to the direction of the first channels (not shown) for circulation of the first fluid in the heat exchange tubes 5, in other words here parallel to the longitudinal direction of the heat exchange tubes 5 .

• deux bords opposés 13A, 13B s'étendant perpendiculairement à la direction générale d'écoulement du premier fluide, et
• deux autres bords opposés 13C, 13D s'étendant parallèlement à la direction générale d'écoulement du premier fluide.

The first frames 13 can also be defined relative to the general direction of flow of the first fluid, namely that the first frames 13 have:

• two opposite edges 13A, 13B extending perpendicular to the general direction of flow of the first fluid, and
• two other opposite edges 13C, 13D extending parallel to the general direction of flow of the first fluid.

The general direction of flow of the first fluid is understood to be the direction of circulation in “I” in the case of a one-pass circulation of the first fluid, or the direction of the branches of the “U” in the case of 'a circulation in two passes of the first fluid.

In the example illustrated, the first frames 13 are of generally substantially rectangular shape and have two longitudinal edges 13C, 13D, forming long sides, extending substantially parallel to the general direction of flow of the first fluid and two edges lateral 13A, 13B, forming short sides, extending in the width direction, substantially perpendicular to the direction of flow of the first fluid.

However, according to other embodiments, provision could be made for frames having a general shape which is not rectangular, for example elliptical, or in the form of a diamond.

The longitudinal axis of the first frames 13 and the heat exchange tubes 5 is here combined.

These first frames 13 have the same thickness as the heat exchange tubes 5 which they receive, in particular of the order of a few millimeters, for example of the order of 1mm.

As before, the thickness is considered in the direction of the height of the heat exchange bundle 3, we can also speak of the height of the first frames 13.

In other words, it is the thickness in the stacking direction of the frames 13, 15.

Thus, the heat exchange tubes 5 can be held in the respective first frames 13 before the different frames 13, 15 are superimposed.

Each first frame 13 can receive a heat exchange tube 5 or, as a variant, at least two heat exchange tubes 5, as illustrated in the figures 2 to 5 , so that the heat exchange bundle 3 then has at least two rows of heat exchange tubes 5.

To this end, each first frame 13 has two housings 130 for receiving in each housing 130 an associated heat exchange tube 5.

In addition, in order to allow circulation in at least two passes of the first fluid, two adjacent heat exchange tubes 5 arranged in a first frame 13 can communicate with each other at one end.

The placing in fluid communication at one end of two adjacent heat exchange tubes 5 received in the same first frame 13 is advantageously ensured by a second frame 15 as will be described in more detail below.

Furthermore, in order to allow the flow of the first fluid in the heat exchange bundle 3, the first frames 13 comprise means for placing in fluid communication 131 the first circulation channels of the first fluid with the manifold 19.

The means for placing in fluid communication 131 of each first frame 13 are advantageously arranged in fluid communication with the means for putting in fluid communication 131 of the other first frames 13 of the heat exchange bundle 3 and with the manifold 19.

The fluid communication means 131 provided on the first frames 13 allow, in a simple way, to collect the first fluid and to distribute it, for example in the heat exchange tubes 5 held in these first frames 13. It is no longer necessary to provide the collectors on each side of the tubes as in the known solutions.

According to the example illustrated on the figures 2 to 5 , the first frames 13 respectively have a predefined number of recesses 131 forming the means of fluid communication, in which the ends, in particular the longitudinal ends, of the heat exchange tubes 5 open.

Of course, the number of recesses 131 is adapted as a function of the number of first circulation channels in the heat exchange tubes 5.

These recesses 131 are here provided on two opposite edges 13A, 13B (see Figures 4 and 5 ) first frames 13 which are opposite the ends of the heat exchange tubes 5.

These are the lateral edges 13A, 13B of the first frames 13.

The first frames 13 are arranged so that their recesses 131 are in fluid communication with the recesses 131 of the other first frames 13. Here, the recesses 131 of the first frames 13 are aligned in the direction of the height of the heat exchange bundle 3 .

In addition, with reference to Figures 1 and 2 , on one side of the first frames 13, the recesses 131 are aligned with the manifold 19.

According to one embodiment, at least one lateral edge 13A, 13B of a first receiving frame 13, arranged opposite one end of a heat exchange tube 5, is shaped according to a pattern defining a succession of arches.

The arches are advantageously arranged over the entire width of the lateral edge which is opposite one or more ends of the heat exchange tube (s) 5. In other words, the arches are provided over the entire width of the set of tubes heat exchange 5 that the first frame 13 can receive, here two heat exchange tubes 5.

The term “arch” is understood to mean the assembly formed by an arch vault 132 connecting two arch legs 133. In this succession of arches, two adjacent arch vaults 132 are connected by a common arch leg 133.

According to the example illustrated, a recess 131 is delimited by an arch, otherwise said each recess 131 is made between two adjacent arch legs 133 and is delimited by these two arch legs 133 and the arch vault 132 connecting them.

When a heat exchange tube 5 is arranged in the housing 130 of a first frame 13, the space remaining between one end of the heat exchange tube 5 and an arch vault 132 makes it possible to define a through opening of fluid communication.

Finally, in a complementary manner to the two rows of heat exchange tubes 5, namely a first row of first heat exchange tubes 5 and a second row of second heat exchange tubes 5, the fluid communication means 131 can define two rows respectively associated with a row of heat exchange tubes 5.

Thus, first communication means 131 ensure the fluid communication of the first heat exchange tubes 5 or in other words of the first row of first heat exchange tubes with the manifold 19. And, second means placing in communication 131 ensures the fluidic communication of the second heat exchange tubes 5 or in other words of the second row of second heat exchange tubes with the manifold 19.

In addition, each first frame 13 advantageously comprises at least one stress absorption zone on at least one lateral edge 13A, 13B facing one end of a heat exchange tube 5.

Such a stress absorption zone is able to withstand mechanical stresses, in particular due to pressure.

The stress absorption zones can be produced by a predetermined number of stress absorption legs formed on at least one lateral edge 13A, 13B of a first frame 13 opposite one end of a heat exchange tube 5.

These stress absorption legs extend towards the end of the heat exchange tube 5. In the example illustrated on the figures 2 to 5 , the arch feet 133 perform this function of stress absorption legs.

The arches are therefore dimensioned taking into account the mechanical strength of the first frame 13 and the flow of the first fluid through the recesses 131 defined by the arches.

In addition, in the case of a heat exchanger 1 assembled by brazing, the arch feet 133 also make it possible to define brazing zones with the second frames 15.

Furthermore, in order to allow the flow of the second fluid in the heat exchange bundle 3, the first frames 13 also have guides 134 for the passage of the second fluid.

According to the example illustrated, the first frames 13 are respectively shaped with at least one handle 134 which, when a heat exchange tube 5 is arranged in the first frame 13, makes it possible to define a through opening for passage allowing the flow of the second fluid.

The handles 134 make it possible to define the guides for the passage of the second fluid. The handles 134 of each first frame 13 are arranged in alignment with the handles 134 of the other first frames 13 of the heat exchange bundle 3 so as to allow the second fluid to flow through the bundle 3.

By way of illustration, the figures show various embodiments of the handles 134, in particular the figure 1 illustrates a first embodiment of the handles 134 of substantially rounded shape, while the figures 2 to 5 illustrate a second embodiment of the handles 134, the outline of which is more straight. Of course, any other form of the handles 134 can be envisaged.

In addition, each first receiving frame 13 may have at least one partition 135 which compartments the first receiving frame 13. This partition 135 is here arranged in the extension of an arch foot 133.

In the example illustrated on figures 2 to 5 , each first receiving frame 13 has a partition 135, for example substantially central, which partitions the first receiving frame 13 into two housings 130 (see figure 5 ) to each receive a heat exchange tube 5.

The partition 135 is therefore found arranged between two tubes heat exchange 5 when they are placed in the first frame 13. In this example, the partition 135 extends over the entire length of the heat exchange tubes 5 received in the first frame 13.

The partition 135 of a first frame 13 can be made in one piece with this first frame 13. Such a first frame 13 can be made by stamping in a simple manner.

Second frames

With reference to the figure 6 , we now describe the second frames 15.

The second frames 15 can be at least partially made of aluminum.

When the second frames 15 receive turbulators 11, the second frames 15 are called turbulator frames or turbulator-carrying frames.

• deux bords opposés s'étendant parallèlement à la direction des premiers canaux (non visibles sur les figures) de circulation du premier fluide dans les tubes d'échange thermique 5, autrement dit ici parallèlement à la direction longitudinale des tubes d'échange thermique 5, et
• deux autres bords opposés s'étendant de façon perpendiculaire à la direction des premiers canaux (non visibles sur les figures) de circulation du premier fluide dans les tubes d'échange thermique 5, autrement dit ici perpendiculairement à la direction longitudinale des tubes d'échange thermique 5.

Similar to the first frames 13, the second frames 15 have:

• two opposite edges extending parallel to the direction of the first channels (not visible in the figures) for circulation of the first fluid in the heat exchange tubes 5, in other words here parallel to the longitudinal direction of the heat exchange tubes 5, and
• two other opposite edges extending perpendicular to the direction of the first channels (not visible in the figures) for circulation of the first fluid in the heat exchange tubes 5, in other words here perpendicular to the longitudinal direction of the exchange tubes thermal 5.

• deux bords opposés s'étendant parallèlement à la direction générale d'écoulement du premier fluide, et
• deux autres bords opposés s'étendant perpendiculairement à la direction générale d'écoulement du premier fluide.

It is also possible to define the second frames 15 with respect to the general direction of flow of the first fluid, namely that the second frames 15 have:

• two opposite edges extending parallel to the general direction of flow of the first fluid, and
• two other opposite edges extending perpendicular to the general direction of flow of the first fluid.

• deux bords opposés s'étendant parallèlement à la direction générale d'écoulement du deuxième fluide, et
• deux autres bords opposés s'étendant perpendiculairement à la direction générale d'écoulement du deuxième fluide.

In addition, according to the embodiment described, it is also possible to define the second frames 15 with respect to the general direction of flow of the second fluid flowing against the current of the first fluid, namely that the second frames 15 have:

• two opposite edges extending parallel to the general direction of flow of the second fluid, and
• two other opposite edges extending perpendicular to the general direction of flow of the second fluid.

The general direction of flow of the second fluid is understood to be the direction of circulation in “I” in the case of a one-pass circulation of the second fluid, or the direction of the branches of the “U” in the case of 'a circulation in two passes of the second fluid.

In the example illustrated, the second frames 15 are of general shape similar to the first frames 13, here substantially rectangular.

The second frames 15 have two longitudinal edges, forming long sides, extending substantially parallel to the longitudinal edges of the first frames 13 and to the general direction of flow of the second fluid, and two lateral edges, forming short sides, extending in the width direction, substantially perpendicular to the direction of flow of the second fluid parallel to the lateral edges of the first frames 13.

According to the embodiment described, the second frames 15 extend over the same length and the same width as the first frames 13.

In particular, the outer contours of the first frames 13 and second frames 15 are practically identical so that the alternating stacking of the first frames 13 and second frames 15 forms a block.

More particularly, each second frame 15 defines an internal width and an internal length.

The term "internal width" means the width defined between the internal walls of the opposite longitudinal edges. Likewise, the term "internal length" means the length defined between the internal walls of the opposite lateral edges.

In addition, the side edges of the second frames 15 may be slightly larger than the side edges of the first frames 13, so that the ends heat exchange tubes 5 received in the first frames 13 stacked with the second frames 15, rest on the peripheral edge of the lateral edges of the second frames 15.

The second frames 15 therefore define an internal length less than the internal length defined by the interior space of the first frames 13.

The second frames 15 have a thickness which is of the order of a few millimeters, for example of the order of 0.5mm to 4mm, preferably of the order of 2mm. The thickness is here considered in the direction of the height of the heat exchange bundle 3, we can also speak of the height of the second frames 15. In other words, it is the thickness in the stacking direction of the frames 13, 15.

Similarly to the first frames 13, the second frames 15 can be produced by stamping cutting.

A plurality of second frames 15, called intermediate frames, are arranged between two first frames 13 for receiving the heat exchange tubes 5, thus defining the pitch between two stages of heat exchange tubes 5.

According to a nonlimiting embodiment, the heat exchange bundle 3 may further comprise a second end frame optionally arranged between a first frame 13 and a closure plate, in particular the lower closure plate 17. Such a second end frame can be put in place for reasons of mechanical strength.

Of course, a stack of first frames 13 and second frames 15 is advantageously provided without such an end frame.

According to the embodiment illustrated in the figure 6 , the second frames 15 allow a circulation in two passes of the second fluid.

To this end, the second frames 15 each comprise a bar 150 arranged inside the respective second frame 15 so as to separate two circulation passes for the second fluid. It is therefore an internal bar 150.

In the example illustrated, the bar 150 makes it possible to conform the second circulation channel 9 substantially in a "U" shape.

Of course, provision could be made for a circulation of the second fluid in addition to two passes in a second frame 15 and for this purpose more than one bar 150 inside the second frame 15 which would, by way of nonlimiting example, be arranged offset and opposite one with respect to the other.

The bar 150 extends longitudinally inside a second frame 15. The bar 150 therefore extends in this example substantially parallel to the longitudinal edges of the second frame 15.

To do this, the bar 150 does not extend over the entire internal length of the second frame 15.

In other words, the bar 150 extends from a lateral edge of a second frame 15 in the direction of the opposite lateral edge but without reaching this opposite lateral edge. The bar 150 is therefore secured to a lateral edge of a second frame 15 and projects with its free end towards the internal space of the second frame 15 in the direction of the opposite lateral edge, leaving a space.

The internal bar 150 therefore extends longitudinally from a lateral edge of a second frame 15 over a length less than the internal length of the second frame 15.

The internal bar 150 does not extend over the entire internal width of the second frame 15 either.

More specifically, the internal bar 150 has a smaller width than the internal width of the second frame 15. The width of the internal bar 150 may be greater than or equal, preferably strictly greater, to the thickness of the second frame 15. We define thus on each side of the bar 150, the inlet and the outlet of the flow path for the second fluid.

The bar 150 can also be described as a tongue. In addition, the bar 150 is substantially the same thickness as the second frame 15.

The bar 150 is for example arranged substantially centrally. More precisely, the bar 150 is arranged substantially in the center of a second frame 15 in the width direction of the second frame 15.

In this way, the bar 150 divides the second frame 15 into two parts of the same size.

Advantageously, the internal bar 150 extends over a length at least equal to half the internal length of a second frame 15.

According to the embodiment illustrated with reference to figures 2 to 6 , the internal bars 150 of the second frames 15 are located opposite the partitions 135 of the first frames 13.

In addition to the first frames 13, the second frames 15, in particular the second intermediate frames 15, have guides 151 for the passage of the first fluid allowing its flow in the stack of the first receiving frames 13 and the second frames 15, especially dividers.

The guides 151 are here produced in the form of through-passage orifices 151 arranged in alignment with the recesses 131 for placing the first receiving frames 13 in fluid communication, delimited here by the succession of arches.

The through passage holes 151 are therefore arranged on at least one lateral edge of a second frame 15, here of a second intermediate frame 15.

Of course, the number of through passage openings 151 is adapted as a function of the number of recesses 131 and therefore of the number of first circulation channels of the heat exchange tubes 5.

In addition, the second frames 15 respectively have means for placing in fluid communication 152 the second circulation channels 9 between them on the one hand and with the pipes 21 for the second fluid on the other hand.

The fluid communication means 152 provided on the second frames make it possible to collect the second fluid and distribute it between the heat exchange tubes.

According to the example illustrated on the figure 6 , the second frames 15 respectively have a predefined number of through openings 152, here two through openings 152, for fluid communication.

The through openings 152 are here arranged on the longitudinal edges of the second frames 15 and are aligned with each other in the height direction of the heat exchange bundle 3, in other words in the stacking direction of the different frames 13 , 15.

The through openings 152 lead respectively to the interior of a second frame 15.

In addition, the through openings 152 are arranged on the same side of a second frame 15 in the longitudinal direction, that is to say here to the right or to the left, in a complementary manner to the arrangement of the pipes 21 on a same side of the heat exchange bundle 3, here on the right with reference to the arrangement shown on the figure 1 .

The through openings 152 make it possible to define a fluid inlet 152 towards the interior space of the second frame 15 on a longitudinal edge, and a fluid outlet 152 out of the second frame 15 on the opposite longitudinal edge.

More precisely, according to the example illustrated, the second frames 15 have handles 153 which make it possible to delimit the through openings 152.

The handles 153 of the second frames 15 are produced in a similar manner to the handles 134 of the first frames 13 and are aligned with these handles 134 which allow the passage of the second fluid through the heat exchange bundle 3.

By way of illustration, the figures show different embodiments of the handles 153, in particular, the figure 1 illustrates a first embodiment of the handles 153 of substantially rounded shape, while the figure 6 illustrates a second embodiment of the handles 153, the outline of which is more straight.

Of course, when the handles 134 of the first frames 13 are produced according to the first embodiment, the handles 153 of the second frames 15 are produced in a similar manner according to the first embodiment.

And, when the handles 134 of the first frames 13 are produced according to the second embodiment, the handles 153 of the second frames 15 are produced in a similar manner according to the second embodiment example. Of course, any other form of the handles 153 can be envisaged.

Among the two handles 153 of the second frames 15, the opening delimited by a first handle is arranged in fluid communication with a first tube 21 and the opening delimited by a second handle is arranged in fluid communication with a second tube 21.

Furthermore, as said previously, the heat exchanger 1 is preferably assembled by brazing.

The second frames 15 are intended to be assembled by brazing to the first frames 13. In particular, the longitudinal edges of the second frames 15 are intended to be assembled by brazing to the longitudinal edges of the first frames 13 and the lateral edges of the second frames 15 are intended to be assembled by brazing with the arch legs 133 provided on the lateral edges of the first frames 13.

Furthermore, the second frames 15, in particular the second intermediate frames 15, can also be shaped to put in fluid communication two heat exchange tubes 5 received in the same first frame 13 as illustrated on the figures 2 to 4 .

It is therefore the second frames 15 which allow the circulation in at least two passes of the first fluid in each first frame 13, while guaranteeing good mechanical strength of the first frames 13 due to the CO ₂ under high pressure circulating in the tubes. heat exchange 5.

More precisely, each second frame 15, in particular an intermediate frame, advantageously has at least one turning orifice 155 (see figures 2 and 6 ) which is in fluid communication with both a first and a second fluid communication means 131, here a first and a second recesses 131, of the first frames 13 on either side of the second intermediate frame 15.

Thus, each reversal orifice 155 is arranged between two adjacent heat exchange tubes 5 received in a first frame 13 and in fluid communication with these two heat exchange tubes 5.

In this way, the first fluid which emerges from a first heat exchange tube 5 undergoes a reversal in the reversal orifice 155 then circulates to a second heat exchange tube 5.

The two rows of heat exchange tubes 5 arranged in the first frames 13 then communicate at one end via the reversal orifices 155 provided on the second frames 15, in particular spacers.

Each reversal orifice 155 is here formed between passage orifices through 151 on at least one side edge of each second frame 15, in particular intermediate.

Each reversal orifice 155 advantageously has a longitudinal shape extending substantially perpendicular to the general direction of flow of the first fluid in the two heat exchange tubes 5.

In this example, each turning orifice 155 has a longitudinal shape extending perpendicular to the longitudinal edges of the second frame 15, in particular in between.

In particular, each reversal orifice 155 arranged opposite a first receiving frame 13 extends longitudinally on either side of the partition 135 of this first receiving frame 13, as is better visible on FIG. 16. As an example, the reversal orifice 155 has a substantially oblong shape.

Furthermore, the reversal orifice 155 is dimensioned so as to have a section for the reversal of the first fluid at least equal to the section of passage of a heat exchange tube 5.

Furthermore, preferably, provision is made, in a complementary manner, for a circulation in two passes, called a "U" shape, of the first fluid in a first receiving frame 13 and a circulation in two passes, called a "U" shape, for the second fluid in a second frame 15. The heat exchanger 1 is then dual circulation in "U".

Thus, the heat exchanger 1 comprises a stack of first frames 13 receiving one or more heat exchange tubes 5 and second frames 15 advantageously receiving turbulators 11. These are simple elements and can be assembled easily, by brazing in particular.

Such a heat exchanger 1 as described above also has very good resistance to high pressures, in particular due to the circulation of CO ₂ , as well as optimized heat exchange performance.

In particular, the shape of the edges of the first frames 13 receiving the heat exchange tubes 5 with stress absorption zones formed by arch legs 133 makes it possible to obtain a heat exchanger 1 having better mechanical strength compared to the solutions of the prior art. In addition, these arch legs 133 advantageously form brazing zones with the second frames 15.

Claims (8)

1. Heat exchanger (1), in particular for a motor vehicle, said exchanger (1) comprising a heat-exchange bundle (3) with a plurality of heat-exchange tubes (5) defining circulation ducts for a fluid:

   - the heat-exchange bundle (3) comprising a plurality of first frames (13) for receiving the heat-exchange tubes (5), and in that

   - the first frames (13) for receiving the heat-exchange tubes respectively comprising at least one stress-absorption region (133) arranged on at least one edge (13A, 13B) opposite an end of a heat-exchange tube (5) and able to withstand the mechanical stresses, the heat exchanger being characterized in that the stress-absorption regions are produced by a predetermined number of stress-absorption legs (133) formed on at least one edge (13A, 14B) of a first receiving frame (13) opposite an end of a heat-exchange tube (5) and extending in the direction of the end of the heat-exchange tube (5).
2. Heat exchanger (1) according to the preceding claim, in which the stress-absorption legs (133) extend longitudinally substantially parallel to the direction of flow of the fluid in the circulation ducts.
3. Heat exchanger (1) according to either of Claims 1 and 2, in which the first frames (13) have a plurality of recesses (131), and in which two adjacent stress-absorption legs (133) extend on either side of a recess (131).
4. Heat exchanger (1) according to any one of Claims 1 to 3, in which the first frames (13) respectively have at least one edge (13A, 13B) opposite an end of a heat-exchange tube (5) that is configured with a pattern defining a succession of arches, the arch feet (133) forming the stress-absorption legs.
5. Heat exchanger (1) according to Claims 3 and 4, comprising at least one fluid manifold (19), and in which, when heat-exchange tubes (5) are received in the first frames (13), the vaults (132) of the arches define, with the ends of the heat-exchange tubes (5), openings for establishing fluid communication between the manifold (19) and the heat-exchange tubes (5), with the result that an opening for establishing fluid communication is arranged between two arch feet (133).
6. Heat exchanger (1) according to any one of Claims 1 to 5, which is assembled by brazing and in which the stress-absorption legs (133) define brazing regions.
7. Heat exchanger (1) according to any one of the preceding claims, in which a first fluid is able to circulate in the heat-exchange tubes (5), and additionally comprising a plurality of second frames (15) respectively arranged in alternating fashion with the first frames (13) for receiving the heat-exchange tubes (5), and respectively defining a second circulation duct (9) for a second fluid so as to allow a heat exchange between the first fluid and the second fluid.
8. Heat exchanger according to Claim 5 taken in combination with Claim 8, in which the second frames (15) have through-passage orifices (151) arranged in alignment with the recesses (131) so as to allow the flow of the first fluid in the stack of the first frames (13) and of the second frames (15).

Images