FR3045800A1 - THERMAL EXCHANGER, IN PARTICULAR FOR MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a heat exchanger for a heat exchange between at least a first fluid and a second fluid, in particular for a motor vehicle: the heat exchanger comprising a heat exchange bundle with an alternating stack of: exchange tubes heat pump (5) having circulation channels (7) for the first fluid, and • spacers (15), and - the heat exchanger having at least partially a meltable coating during solder assembly. According to the invention: - the spacers (15) respectively have at least one reservoir (154) capable of collecting the coating during brazing of the heat exchanger (1), - each reservoir (154) being arranged on an end of an interlayer (15) and opposite one end of a heat exchange tube (5), so as to prevent the coating from clogging said at least one circulation channel (7) during soldering of the heat exchanger .

Description

The invention relates to the field of heat exchangers. The invention relates more particularly to heat exchangers adapted to be traversed by a refrigerant fluid having a relatively high operating pressure, as is the case with natural gases such as carbon dioxide designated by CO2, having an operating pressure. superior to the refrigerant gases used in the solutions of the state of the art.

Such heat exchangers find particular application in motor vehicles. They may in particular constitute a gas cooler in which the coolant such as CO2 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 referred to as "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 too cold, their autonomy can decrease strongly and if they are subjected to too high temperatures, there is a risk of thermal runaway up to to the destruction of the battery, or even the motor vehicle. In order to regulate the temperature of the batteries, it is known to use a coolant, generally coolant comprising a mixture of brine, which circulates in 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 CO2 circulating in the gas cooler. The coolant can also, if necessary, absorb the heat emitted by the battery or batteries to cool them and remove this heat at one or more other heat exchangers.

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

However, the use of a refrigerant such as CO2 under a very high pressure, generally greater than 100 bar, with a burst pressure which can reach, for example, up to 340 bar, implies that heat exchangers such as gas coolers, must withstand such high pressures.

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 the second fluid such as the cooling liquid. Plate heat exchangers known from the prior art do not allow to withstand such high pressures.

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

However, such an architecture is complex to achieve and in particular has drawbacks in terms of sealing, particularly in the case of a brazed heat exchanger for which it proves necessary to provide multiple soldering points for several pieces of the heat exchanger. In addition, with this architecture, the two fluids circulate generally at cross flow. It is not always possible to provide a flow against the current or in several passes of the two fluids, which 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, the heat exchangers can in particular be assembled by soldering. For this purpose, a solder material is generally provided on different elements of the heat exchanger. However, during brazing, the solder material that melts can plug the channels in which is intended to circulate at least one fluid, including the refrigerant.

Moreover, 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 solve the disadvantages described above by providing a heat exchanger whose assembly by soldering is improved. For this purpose, the subject of the invention is a heat exchanger for a heat exchange between at least a first fluid and a second fluid, in particular for a motor vehicle: the heat exchanger comprising a heat exchange bundle with an alternating stack: heat exchange tubes having circulation channels for the first fluid, and interleaves, and the heat exchanger having at least partially a meltable coating so as to join the elements of the heat exchanger. during soldering assembly.

According to the invention, the spacers respectively have at least one reservoir capable of collecting the coating during brazing of the heat exchanger, each reservoir being arranged on one end of an insert and opposite one end of a tube of heat exchange, so as to prevent the coating from clogging said at least one circulation channel of the heat exchange tube during brazing of the heat exchanger.

Thus, the coating present to ensure the junction between the elements of the heat exchanger assembly is not likely to come clog, when it melts, the circulation channels of the first fluid.

Indeed, the coating that migrates during soldering flows into the tanks facing the ends of the heat exchange tubes instead of risking entering the flow channels of the first fluid accessible to the ends of the heat exchange tubes. The heat exchanger may further comprise one or more of the following features taken alone or in combination.

According to one aspect of the invention, the spacers respectively have at least one reservoir on each face vis-à-vis a heat exchange tube.

According to another aspect of the invention, the heat exchanger comprises an alternating stack: first receiving frames heat exchange tubes, and second frames, at least some second frames forming the spacers, the second frames respectively having the at least one reservoir on at least one edge of the second frame extending substantially perpendicular to the direction of flow of the first fluid in 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, inserted in the first frames and between which circulates the second fluid such as only coolant.

The superimposed frames make it possible to create the flow path of the first refrigerant fluid, when the frames are brazed together, and likewise the superposed frames make it possible to create the coolant flow path, in particular on two opposite sides of the bundle. heat exchange.

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

In the invention, the frames designate a part, or an assembly of parts, which can be rigid, delimiting a closed space or not. 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.

Finally, such a heat exchanger has a better mechanical strength compared to the solutions of the prior art and very good resistance to high pressures, especially due to the circulation of CO2 as a refrigerant.

According to an additional aspect, the reservoir is made by reducing the material of a spacer, or intermediate frame.

According to a further aspect, the reservoir is in the form of a groove extending substantially perpendicular to the direction of flow of the first fluid in the heat exchange tubes.

According to one embodiment, the reservoir extends facing the entire end of a heat exchange tube, for example over the entire width of a heat exchange tube made in the form of a flat tube.

According to another aspect of the invention, the first reception frames present respectively at least one recess at an inner corner receiving a corner of a heat exchange tube, for the flow of the coating during soldering of the heat exchanger, so as to prevent the coating from clogging the channels of the heat exchange tubes.

This further prevents the coating from clogging the flow channels defined by the heat exchange tubes when the coating melts and migrates during soldering.

According to one embodiment, the width of the recess is substantially equal to the width of the groove. Other features and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and nonlimiting example, and the appended drawings in which: FIG. 1 is a perspective view of a heat exchanger according to the invention, - Figure 2 schematically shows a first frame of the heat exchange bundle receiving two heat exchange tubes, - Figure 3 is a view of the first single frame of Figure 2, - FIG. 4 is a partial sectional view of a first frame showing a recess for the flow of a coating capable of melting during soldering; FIG. 5 is another perspective view of a stack of first frames and second frames of a heat exchange bundle; FIG. 6 is a partial perspective view showing a tank for the flow of a coating suitable for melting during brazing provided on a second frame, and - Figure 7 is a side sectional view of a second frame having a reservoir on each side.

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

The following achievements 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 features apply only to a single embodiment.

Simple features of different embodiments may also be combined to provide other embodiments.

In the present, the terms upper and lower, or high and low, or vertical and horizontal, are designated with reference to the arrangement of the elements in the figures.

This arrangement corresponds to the arrangement of the elements in the assembled state in a motor vehicle in particular. Heat exchanger

With reference to FIG. 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. This 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 parts, a coating intended to melt to ensure the joining of elements of the heat exchanger during the heat exchange. soldering assembly, as will be detailed later. The heat exchanger 1 according to the invention is particularly suitable for the circulation of at least one fluid having a high operating pressure, in particular greater than 100 bar.

For example, the first fluid is a refrigerant fluid intended to circulate at high pressure such as CO2, also designated by R744 according to the industrial nomenclature. The heat exchanger 1 can in particular be a gas cooler in which the cooling fluid such as CO2 is cooled by a second fluid for example in liquid form, such as cooling liquid comprising a mixture of brine.

The second fluid such as the cooling liquid can also be cooled by the first fluid such as CO2, such a heat exchanger is then commonly referred to as "Water chiller" in English. The heat exchanger 1 comprises a heat exchange bundle 3 for the heat exchange between the first fluid and the second fluid.

In the illustrated example, the heat exchange bundle 3 has a generally parallelepipedal shape.

The circulation of the first and second fluids is advantageously countercurrent in the heat exchange bundle 3. The introduction and the evacuation of the first fluid in the heat exchange bundle 3 or out of the heat exchange bundle 3 is shown by way of example by the arrows Fli for the introduction and Flo for the evacuation.

Similarly, 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 example by the arrows F2i for the introduction and F2o 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 both fluids, as will be described further in detail thereafter.

An example of circulation of the two fluids against the current and in two passes is illustrated schematically by the arrows F1 and F1 in FIG.

More specifically, the heat exchange bundle 3 comprises a plurality of heat exchange tubes 5 (see FIG. 2) stacked so as to alternately define first circulation channels 7 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 made in the form of flat tubes, advantageous in terms of space.

The flat tubes 5 have a generally rectangular general shape, with a length for example of the order of 32 mm and a thickness of about one millimeter. The thickness, or no tube, is here considered in the direction of the height of the heat exchange bundle 3, we can also talk about the height of the heat exchange tubes 5.

In other words, it is the thickness in the stacking direction of the heat exchange tubes 5.

Each heat exchange tube 5 defines a predetermined number of first circulation channels 7 for the first fluid, in particular circulating microchannels 7 for the first fluid.

The first channels or microchannels 7 extend here substantially longitudinally, in a substantially "I" or rectilinear shape.

The first circulation channels or microchannels 7 for the first fluid allow the flow of the first fluid respectively extend in a direction parallel to the longitudinal direction of the heat exchange tubes 5.

The first fluid can follow a circulation in a so-called "I" flow but also a two-pass circulation called "U" circulation as will be described later.

Similarly, the second circulation channels 9 for the second fluid may be shaped to allow circulation in a so-called "I" flow but also a circulation in two passes called "U" circulation as will be described later.

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

The turbulators 11 may be carried by a separate element of the heat exchange tubes 5.

Alternatively, turbulators 11 may be formed on the heat exchange tubes 5, for example by deformations such as corrugations of the heat exchange tubes 5 which protrude into the second circulation channels 9 for the second fluid.

Interlayers 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 dividers. The stack is here substantially vertically.

Each first frame 13 is able to receive 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 sets or stages are repeated as many times as necessary depending on the space available and the performance to be achieved.

The first frames 13 and the second frames 15 are described in more detail below. By way of example, closure plates 17, 18 (see FIG. 1), in particular at least one bottom closure plate 17 and at least one top closure plate 17, 18, can be arranged on either side of the stacking of the first frames 13 and the second frames 15, so as to close the heat exchange bundle 3.

Referring to FIG. 1, the heat exchanger 1 further comprises at least one manifold 19 of the first fluid arranged in fluid communication with the first circulation channels 7.

The manifold 19 is according to the illustrated example arranged on an upper closure plate 18 disposed at the top of the heat exchange bundle 3. The heat exchanger 1 further comprises at least two inlet and outlet manifolds 21 of fluid allowing the introduction and the evacuation of the second fluid.

In this example, the two tubes 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, it is possible to arrange the two pipes 21 on the bottom plate 17.

According to another variant not illustrated, provision can be made to separately arrange the pipes 21 with a pipe 21 on the upper plate 18 and the other pipe 21 on the bottom plate 17.

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

According to the arrangement illustrated in Figure 1, the manifold 19 is arranged on the left while the pipes 21 are arranged on the right.

First frames called tubes-frames

With reference to FIGS. 2 to 4, the first frames 13 for receiving the heat exchange tubes 5 are now described in greater detail.

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

The first frames 13 have two opposite edges 13A, 13B (see FIGS. 2 and 3) extending perpendicularly to the direction of the first circulation channels 7 of the first fluid, in other words here perpendicularly to the longitudinal direction of the tubes. heat exchange 5, and two other opposite edges 13C, 13D extending parallel to the direction of the first flow channels 7 of the first fluid, in other words here parallel to the longitudinal direction of the heat exchange tubes 5.

It is also possible to define the first frames 13 with respect to the general direction of flow of the first fluid, namely that the first frames 13 have: two opposite edges 13A, 13B extending perpendicularly 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 means the direction of the flow in "I" in the case of a flow in one pass 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 illustrated examples, the first frames 13 are of generally 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 side edges 13A, 13B, extending in the width direction, substantially perpendicular to the direction of flow of the first fluid.

However, according to other embodiments, one could provide frames having a general shape that is not rectangular, for example elliptical, or diamond-shaped. The longitudinal axis of the first frames 13 and heat exchange tubes 5 is here confused.

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

As previously, 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 maintained in the respective first frames 13 before superposition of the various frames 13, 15.

According to a variant not illustrated, each first frame 13 may be adapted to receive a single heat exchange tube 5 allowing a flow in one pass of the first fluid. For this purpose, each first frame 13 has a housing 130 for receiving an associated heat exchange tube 5.

According to the embodiment illustrated in FIGS. 2 and 3, each first reception frame 13 is able to receive two heat exchange tubes 5.

The heat exchange bundle 3 then has two rows of heat exchange tubes 5: first heat exchange tubes and second heat exchange tubes.

Advantageously, two adjacent tubes in a first frame 13 communicate with each other at one end so as to allow a two-pass circulation of the first fluid.

The heat exchange bundle 3 thus has at least one reversal zone of the first fluid, that is to say, allowing the first fluid having circulated in a heat exchange tube 5 to circulate to another heat exchange tube 5, namely the adjacent heat exchange tube 5 received in the same first frame 13. Of course, it is possible to provide more than two heat exchange tubes 5 for a circulation of the first fluid in addition to two passes in a first frame 13.

Fluidic communication at one end of two adjacent heat exchange tubes 5 received in a first frame 13 is advantageously provided by a second frame 15 as will be described in more detail later.

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 7 of the heat exchange tubes 5 with the manifold 19.

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

According to the embodiment illustrated with two heat exchange tubes 5 received in each first frame 13, the fluid communication means 131 define two rows respectively associated with a row of heat exchange tubes 5.

Thus, first communicating means 131 ensure the fluidic communication of the first heat exchange tubes 5 or in other words a first row of first heat exchange tubes 5 with the manifold 19.

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

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

Of course, the number of recesses 131 is adapted as a function of the number of first circulation channels 7 of the heat exchange tubes 5.

These recesses 131 are here provided on two opposite edges 13A, 13B of the first frames 13 which are opposite the ends of the heat exchange tubes 5. Here are the lateral edges 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, on one side of the first frames 13, the recesses 131 are aligned with the manifold 19.

According to the illustrated embodiment, at least one side 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 13A, 13B which is opposite the ends of the heat exchange tubes 5 received in the same first frame 13.

In other words, the arches are provided over the entire width of the set of heat exchange tubes 5 that the first frame 13 can receive, here two heat exchange tubes 5.

Arch is understood to mean the group formed by an arch arch 132 connecting two feet of arch 133.

In this succession of arches, two adjacent arch arches 132 are connected by a common arch foot 133.

According to the illustrated example, a recess 131 is delimited by an arch, in other words each recess 131 is made between two adjacent arch feet 133 and is delimited by these two arches 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 arch 132 makes it possible to define a through opening of setting in fluid communication. By way of non-limiting example, the diameter of a through opening is of the order of 0.5 mm.

In addition, each first frame 13 advantageously comprises at least one stress absorption zone on at least one lateral edge 13A, 13B opposite 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 may be made 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 illustrated example, the arches 133 provide this function of stress absorption legs.

The arches are 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 soldering, the arches 133 still allow to define brazing areas with the second frames 15 as will be described later.

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 illustrated example, the first frames 13 are respectively shaped with at least one loop 134 which when a heat exchange tube 5 is arranged in the first frame 13 defines a through through opening allowing the flow of the second fluid. By way of illustration, in the figures, various embodiments of the loops 134, in particular FIG. 1, illustrate a first embodiment of loops 134 of substantially rounded shape, while FIGS. 2, 3 and 5 illustrate a second embodiment. embodiment of the handles 134 whose contour is more rectilinear shape.

Of course, any other form of the handles 134 may be considered.

The handles 134 allow to define the guides for the passage of the second fluid. For example, this through opening has a diameter of the order of 2mm.

The ratio between the diameter of a passage opening of the second fluid and the diameter of a through opening 131 of fluidic communication allowing the flow of the first fluid is in this example of the order of 4.

The loops 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 flow of the second fluid through the heat exchange bundle 3.

In addition, each first reception frame 13 has, according to the embodiment illustrated in FIGS. 2 and 3, at least one partition wall 135 which compartmentalizes the first reception frame 13.

This partition wall 135 is here arranged in the extension of a foot of arch 133.

In the illustrated example, each first receiving frame 13 has a partition wall 135, for example substantially central, which compartmentalizes the first receiving frame 13 in two housings 130 to each receive a heat exchange tube 5.

The partition wall 135 is thus found arranged between two heat exchange tubes 5 when they are put in place in the first frame 13.

In this example, the partition wall 135 extends over the entire length of the heat exchange tubes 5 received in the first frame 13.

The partition wall 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 cutting stamping in a simple manner.

An enlarged portion of a first frame 13 is illustrated in FIG.

As said before the heat exchanger 1 is in particular assembled by brazing. For this purpose, it is expected that the elements of the heat exchange bundle 3, and in particular the first frames 13 and the second 15, at least partially have a coating capable of melting when the assembly passes into the furnace for brazing and migrate in order to plug the gaps between the parts of the heat exchanger 1.

The coating is commonly referred to as "clad" in the field of brazing metal parts, in particular aluminum.

In particular, the coating is added to the core of the parts, such as the first frames 13 and second frames 15, during manufacture, for example by cold rolling.

It may be a non-limiting example of a coating comprising aluminum and silicon.

The percentage of the coating is for example of the order of 5% to 10% of the material of a frame 13,15, for example.

Of course, the percentage of the coating is chosen small enough not to weaken the elements of the heat exchange bundle 3, including the first frames 13 and the second 15, after brazing.

The first frames 13 respectively have at least one recess 139 at an inner corner receiving a corner of a heat exchange tube 5, that is to say on a corner of the inner edge of a first frame 13, which is vis-à-vis with a heat exchange tube 5 when the latter is arranged in the first receiving frame 13.

Such a recess 139 is provided to allow the flow of the coating during brazing of the heat exchanger 1, thus preventing the coating from clogging the first channels or microchannel circulation 7 of the heat exchange tubes 5.

Of course, the design of this roughening 139 takes into account a compromise not to weaken the first frame 13 while being able to collect a sufficient amount of the coating that migrated during soldering.

In a particular example, the width of this recess 139 is substantially equal to the width of a groove 154 provided for a similar purpose on a second frame 15 as described below.

Advantageously, the first frames 13 respectively have four recesses 139 respectively arranged at each of the four inner corners of a first frame 13.

In addition, the recess or recesses 139 are arranged close to the fluid communication connection means 131.

In addition, as can be seen more clearly in FIG. 4, according to the illustrated example in which at least one edge of a first frame 13 is shaped with a succession of arches, at least one recess 139 is made in the extension of an extreme arch, that is to say of the first or last arch of the succession of arches.

Second frames

With reference to FIGS. 5 and 6, the second frames 15 are now described.

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

When the second frames 15 receive turbulators 11, the second frames 15 are said frames-turbulators or turbulators frames.

Similarly to the first frames 13, the second frames 15 have: two opposite edges extending parallel to the direction of the first circulation channels 7 of the first fluid, in other words here in parallel with the longitudinal direction of the heat exchange tubes 5, and two other opposite edges extending perpendicularly to the direction of the first flow channels 7 of the first fluid, ie here perpendicular to the longitudinal direction of the heat exchange tubes 5.

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.

Furthermore, according to the embodiments described, it is still 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 edges opposed 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 means the direction of the circulation in "I" in the case of a circulation in a pass 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 illustrated example, the second frames 15 are of generally similar shape 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 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 side edges of the first frames 13.

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

In particular, the outer contours of the first frames 13 and second frames 15 are substantially identical so that the alternating stack 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.

By "internal width" is meant the width defined between the inner walls of the opposite longitudinal edges.

Similarly, the term "internal length", the length defined between the inner walls of the opposite side edges.

In addition, the lateral edges of the second frames 15 may be slightly larger than the lateral edges of the first frames 13, so that the ends of the 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 L 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 made by stamping cut.

A plurality of second so-called interposed frames 15 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 non-limiting embodiment, the heat exchange bundle 3 may furthermore comprise a second end frame (not shown) optionally arranged between a first frame 13 and a closure plate 17, in particular the closure plate. lower 17.

Such a second end frame can be put in place for reasons of mechanical strength.

Each second frame 15 may be shaped for one-pass circulation of the second fluid. For this purpose, each second frame 15 defines a second circulation channel 9 for the second fluid. The second circulation channel 9 here extends in a substantially "I" shape.

According to the illustrated embodiment, the second frames 15 allow circulation in two passes of the second fluid. For this purpose, the second frames 15 each comprise a bar 150 arranged inside the second frame 15 so as to separate two flow passes for the second fluid.

It is therefore an internal bar 150. In the example illustrated, the bar 150 makes it possible to shape the second circulation channel 9 substantially in a "U" shape.

Of course, it would be possible to provide 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 be, by way of non-limiting example, arranged in an offset manner and opposite to each other.

The strip 150 extends longitudinally inside a second frame 15. The strip 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 side edge of a second frame 15 towards the opposite side edge but without reaching this opposite side edge.

The bar 150 is 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 towards the opposite side edge, leaving a space.

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

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

More specifically, the inner bar 150 has a width smaller than the internal width of the second frame 15.

The inlet and the outlet of the flow path for the second fluid are thus defined on each side of the bar 150.

The bar 150 may also be called tongue. In addition, the bar 150 is substantially of the same thickness as the second frame 15.

The bar 150 is for example arranged substantially centrally. More specifically, 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 inner bar 150 extends over a length l at least equal to half the internal length L of a second frame 15.

According to an exemplary embodiment, each second frame 15 may have an internal length L in a range of about 30mm to 500mm.

Moreover, in the case where the second frames 15 comprising such an inner bar 150 are stacked with first frames 13 each receiving a single heat exchange tube 5, the heat exchange tubes 5 or mono-tubes received in the first frames 13 may rest on the bars 150 of the second frames 15 vis-à-vis.

In a variant, the inner bars 150 of the second frames 15 are opposite partitions 135 of first frames 13 made according to the embodiment illustrated in FIGS. 2 and 3.

Complementarily to the first reception frames 13, the second frames 15, in particular the second intermediate frames 15, have guides 151 for the passage of the first fluid allowing it to flow in the stack of the first reception frames 13 and the second frames 15, in particular spacers. The guides 151 are here made in the form of through-passage orifices 151 arranged in alignment with the recesses 131 forming fluid communication with the first reception frames 13, delimited here by the succession of arches.

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

Of course, the number of throughthrough orifices 151 is adapted as a function of the number of recesses 131 and therefore the number of first circulation channels 7 of the heat exchange tubes 5.

The second end frame, when present, is made similar to a second intermediate frame, except that the second end frame does not have through holes 151 for the passage of the first fluid.

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

According to the illustrated example, the second frames 15 respectively have a predefined number of through-openings 152 for setting into fluid communication.

These through openings 152 are here arranged on the longitudinal edges of the second frames 15 and are aligned with each other in the direction of the height of the heat exchange bundle 3.

The through openings 152 open respectively to the inside of a second frame 15.

In addition, in the example illustrated in Figures 1 and 5, 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 left, in a complementary manner to the arrangement of the tubes 21 on the same side of the heat exchange bundle 3, here on the right with reference to the arrangement shown in FIG. 1.

The through openings 152 define a fluid inlet 152 to the inner 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 specifically, according to the illustrated example, the second frames 15 have handles 153 which define the through openings 152.

The loops 153 of the second frames 15 are made in a manner similar to the loops 134 of the first frames 13 and are aligned with these loops 134 which allow the passage of the second fluid through the heat exchange bundle 3. As an illustration, in the figures various embodiments of the handles 153, in particular FIG. 1, illustrate a first embodiment of the loops 153 of substantially rounded shape, while FIG. 5 illustrates a second embodiment of the handles 153 whose contour is of more rectilinear form.

Of course, when the loops 134 of the first frames 13 are made according to the first embodiment, the loops 153 of the second frames 15 are made similarly according to the first embodiment.

And when the handles 134 of the first frames 13 are made according to the second embodiment, the handles 153 of the second frames 15 are made similarly according to the second embodiment.

Of course, any other form of the handles 153 may be considered.

Among the two loops 153 of the second frames 15, the opening defined by a first loop is arranged in fluid communication with a first pipe 21 and the opening defined by a second loop is arranged in fluid communication with a second pipe 21.

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

The second frames 15 are intended to be soldered to the first frames 13.

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

According to one embodiment, for brazing, the second frames 15 respectively have at least one tank 154, better visible in Figure 6, capable of collecting the coating or "clad" during brazing of the heat exchanger 1.

Each tank 154 is here arranged on a lateral edge of a second frame 15. Advantageously, a tank 154 is provided on each lateral edge of a second frame 15.

Each tank 154 is then located opposite a lateral edge 13A, 13B of a first receiving frame 13 on which an end 50, 52 opens out of a heat exchange tube 5.

Thus, during the brazing assembly of the heat exchanger 1, the coating disposed on the first frames 13 and the second frames 15 opposite, melts and migrates so as to plug the gaps between the parts of the heat exchanger 1 and flows into the tanks 154, thus preventing the melted and migrated coating from clogging the first circulation channels or microchannels 7 of the heat exchange tubes 5.

Advantageously, the tank or reservoirs 154 are provided on each side of a second intermediate frame arranged between two first frames 13.

In the optional case where a second end frame is provided, the reservoir (s) 154 may be arranged on only one face of this second end frame, namely on the face opposite a heat exchange tube 5, and not on the opposite side of the second end frame, vis-à-vis a closure plate 17.

Each tank 154 can be made by local reduction of material of a second frame 15.

The depth p of a tank 154 must be chosen large enough to collect the coating, which is for example of the order of 5% to 10% of the material of the second frame 15, and small enough not to weaken the mechanical strength. of the second frame 15. By way of non-limiting example, the tank 154 may have a depth p of the order of 0.5 mm.

According to the particular example illustrated, the tank 154 is in the form of a groove 154 extending substantially perpendicular to the direction of flow of the first fluid in the heat exchange tubes 5, here in the direction of the width of a second frame 15.

More specifically in this example, the tank 154 extends facing the entire end of a heat exchange tube 5, in other words over the entire width of a tube or of each heat exchange tube 5.

In particular, in the case where the second frames 15 are stacked with first receiving frames 13 as described above according to the fifth embodiment, the width of the groove 154 on a second frame 15 is substantially equal to the width of the recess. 139 on a first frame 13.

Furthermore, the second frames 15, in particular the second intermediate frames, may also be shaped to put into fluid communication two heat exchange tubes 5 received in the same first frame 13 according to the embodiment of the first frames 13 illustrated in FIGS. 2 and 3.

It is therefore the second frames 15 which allow circulation in at least two passes of the first fluid in each first frame 13, while ensuring good mechanical strength of the first frames 13 due to the high pressure CO2 circulating in the exchange tubes thermal 5.

More specifically, each second frame 15, in particular the spacer, advantageously has at least one overturning orifice 155 (see FIG. 5) which is in fluid communication with both a first and a second fluid communication connection means 131, here a first and a second recess 131, first frames 13 on either side of the second spacer frame.

Thus, each turning 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 opens out of a first heat exchange tube 5 undergoes a reversal in the overturning orifice 155 and then flows 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 overturning orifices 155 provided on the second frames 15, in particular spacers.

Each overturning orifice 155 is here provided between through-through orifices 151 on at least one lateral edge of each second frame 15, in particular a spacer.

Each overturning 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 overturning orifice 155 has a longitudinal shape extending perpendicularly to the longitudinal edges of the second frame 15, especially intermediate.

In particular, each turning orifice 155 arranged opposite a first receiving frame 13, extends longitudinally on either side of the partition wall 135 of this first receiving frame 13. By way of example, the turning orifice 155 has a substantially oblong shape.

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

Furthermore, preferably, a two-pass circulation, referred to as a "U", of the first fluid in a first receiving frame 13 according to the second, third or fourth embodiment, and a two-pass circulation, is additionally provided. said "U" of the second fluid in a second frame 15 according to the second embodiment. The heat exchanger 1 is then double "U" circulation.

Thus, the heat exchanger 1 comprises a stack of heat exchange tubes 5 advantageously received in first frames 13 and second frames 15 advantageously receiving turbulators 11.

It is simple element and can be assembled easily, by soldering. The tanks 154 provided on the end edges of the second frames 15 allow the coating which melts and migrates during brazing to flow into these tanks 154 thus avoiding clogging the first channels or microchannels 7 circulation for the first fluid in the heat exchange tubes 5.

Claims (8)

1. Heat exchanger (1) for a heat exchange between at least a first fluid and a second fluid, in particular for a motor vehicle: the heat exchanger (1) comprising a heat exchange bundle (3) with an alternating stack: Heat exchange tubes (5) having circulation channels (7) for the first fluid, and • spacers (15), and - the heat exchanger (1) having at least partially a coating suitable for melting in order to ensure the joining of elements of the heat exchanger during a solder assembly, characterized in that: - the spacers (15) respectively have at least one reservoir (154) capable of collecting the coating during soldering of the heat exchanger (1), - each reservoir (154) being arranged on one end of a spacer (15) and facing one end of a heat exchange tube (5), so as to prevent the coating of e blocking said at least one circulation channel (7) of the heat exchange tube (5) during brazing of the heat exchanger (1). 2. Heat exchanger (1) according to the preceding claim, wherein the spacers (15) respectively have at least one reservoir (154) on each face vis-à-vis a heat exchange tube (5). 3. Heat exchanger (1) according to one of claims 1 or 2, comprising an alternating stack: - first frames (13) for receiving the heat exchange tubes, and - second frames (15), at least some second frames forming the spacers, the second frames (15) respectively having at least one reservoir (154) on at least one edge of the second frame (15) extending substantially perpendicular to the direction of flow of the first fluid in the heat exchange tubes (5). 4. Heat exchanger (1) according to any one of the preceding claims, wherein the reservoir (154) is made by reducing material of a spacer (15). 5. Heat exchanger (1) according to any one of the preceding claims, wherein the reservoir is in the form of a groove (154) extending substantially perpendicular to the flow direction of the first fluid in the tubes. heat exchange (5). 6. Heat exchanger (1) according to any one of the preceding claims, wherein the reservoir (154) extends facing the entire end of a heat exchange tube (5), for example over the entire width of a heat exchange tube (5) formed as a flat tube. 7. heat exchanger (1) according to claim 3 taken together with any one of the preceding claims, wherein the first frames (13) receive respectively at least one recess (139) at an inner corner receiving a wedge of a heat exchange tube (5), for the flow of the coating during soldering of the heat exchanger (1), so as to prevent the coating from clogging the channels (7) of the heat exchange tubes (5). 8. Heat exchanger (1) according to claim 5 taken in combination with claim 7, wherein the width of the recess (139) is substantially equal to the width of the groove (154).