HEAT EXCHANGER, IN PARTICULAR FOR MOTOR VEHICLE

The invention relates to the field of heat exchangers.

The invention relates more particularly to heat exchangers suitable for carrying a fluid coolant having a relatively high operating pressure, as is the case of natural gas such as carbon dioxide designated by co2, having an operating pressure than the refrigerant used in the solutions of the state of the art.

Such heat exchangers have particular application in motor vehicles. They can in particular constitute a gas cooler in which the refrigerant fluid 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 "waste water chiller" in English.

Such heat exchangers can be used in the temperature control of one or more batteries of an electric or hybrid vehicle. The temperature control batteries is an important consideration because if the batteries are subjected to temperatures too cold, battery life can decrease strongly and if they are subjected to temperatures too large, there is a risk of thermal runaway that can lead to the destruction of the battery, or even the vehicle. In order to regulate the temperature of the batteries, it is known to use a heat transfer fluid, generally cooling fluid comprising a mixture of glycol water, which circulates within a heat exchanger in contact with the at least one battery. The cooling liquid, thus supplying heat to the batteries or to be heated, the heat having been absorbed by the cooling liquid for instance during heat exchange with the co2 flowing in the gas cooler. The coolant may also, if desired, absorb heat emitted by the at least one battery to cool them and removing this heat at one or more other heat exchangers.

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

However, the use of a cooling fluid such as the co2 extremely high pressure, generally greater than 100 bar, with a burst pressure which can reach for example up to 340bars, implies that the heat exchangers such as gas coolers, can withstand such high pressures.

Known for example heat exchangers comprising a stack of plates for the circulation of the first fluid, such as coolant or refrigerant gas, and the second fluid such that the cooling liquid. The plate heat exchangers known prior are not capable of withstanding such high pressures.

To counter this, also known prior heat exchangers comprising a stack of tubes connected to one another by at least one header of the first fluid including the coolant of each side of the tubes, and the second fluid, for example in liquid form, may flow around the tubes in a casing connected to a water box.

However such an architecture is complex to make and has special drawbacks in terms of sealing, in particular in the case of a brazed heat exchanger where it is found necessary to provide multiple points of brazing for multiple parts of the heat exchanger. In addition, with this architecture, the two fluids circulate generally cross flow. It is not always possible to provide a counter-current flow or in multiple passes of the two fluids, thereby limiting the effectiveness of the heat exchanger. It has also been found that such a heat exchanger does not always good mechanical stability.

Further, the heat exchangers can in particular be assembled by brazing. For this purpose, a braze material is generally provided on various elements of the heat exchanger. However during brazing, the braze material that melts can come to seal these channels in which is intended to circulate at least one fluid, especially the cooling fluid.

Furthermore, a problem of constant heat exchangers implemented in a vehicle resides in the allocation of a place reduced, to meet the requirements of manufacturers.

The present invention aims to improve the solutions of the state of the technique and to at least partially resolve the disadvantages exposed above by providing a heat exchanger whose brazed joint is improved.

For this purpose, the invention concerns a heat exchanger for heat exchange between at least a first fluid and a second fluid, in particular for a motor vehicle:

the heat exchanger comprising a plurality of heat exchange tubes respectively defining at least one flow channel of the first fluid, the heat exchanger having at least partially a coating which melts to provide joining of members of the heat exchanger during a brazed joint.

According to the invention, the heat exchanger includes a plurality of first receiving frames of the heat exchange tubes, and the first frames each have at least one setback in an inside corner receives a wedge of a heat exchange tube, for the flow of the coating during soldering of the heat exchanger, so as to prevent the coating from obstructing the circulation of the first fluid channels of the heat exchanger tubes.

Thus, the coating present for securing the joint between the elements of the heat exchanger assembly will not into a plugging, upon thawing, the circulation of the first fluid channels. In effect, the excess braze material flows through the one or more setbacks provided on one or more inside corners of the frames near the corners of the ends of the heat exchange tubes instead of risking to slip into the circulation of the first fluid channels accessible at the ends of the heat exchange tubes.

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

It should be noted that the heat transfer core, which has a plurality of heat exchange tubes, is distinct from the frames.

The heat exchanger may further include one or more of the following characteristics taken singly or in combination.

According to one aspect of the invention, each first frame has four cranks respectively arranged at an inside corner of the first frame.

According to another aspect of the invention, the heat exchanger includes at least one collecting tank of the first fluid, and the first frames comprise means for providing fluid communication between the manifold and the heat exchange tubes and at least one recess is arranged close to the means for providing fluid communication.

In one embodiment, the first frames each have at least one edge in respect to one end of a heat exchange tube configured in a pattern defining a series of undulations, and at least one recess is formed in the extension of an archway extrêmale.

In yet another aspect of the invention, the heat exchanger includes a plurality of second frames alternating with the first receiving frames of the heat exchanger tubes.

The heat exchanger thus comprises a stack of simple elements, namely frames and heat exchange tubes in which the first fluid flows, such that the refrigerant gas, inserted into the first frames between which the second fluid flows such as liquid cooling.

The superimposed frames aids in creating the flow path of the first refrigerant fluid, when the frames are brazed together, and similarly, the frames superimposed aids in creating the flow path of cooling liquid in particular on two opposite sides of the heat transfer core.

This architecture allows a simpler embodiment of the heat exchanger as a whole.

Finally, such a heat exchanger has a better mechanical hold with respect to the known solutions and very good resistance to high pressures, particularly due to circulation co2 as refrigerant gas.

According to an additional aspect, the second frames each have at least one groove on at least one edge of the second frame extending substantially perpendicular to the direction of flow of the first fluid. This prevents the more the coating from obstructing the flow channels defined by the heat exchange tubes when the liner bottom and migrates during brazing.

In one embodiment, the width of the groove is substantially equal to the width of the step.

Other features and advantages of the invention will appear more clearly upon reading of the following description, exemplary illustrative and not limiting, and of attached drawings among which:

figure 1 - is a perspective view of a heat exchanger according to the invention,

figure 2 - schematically represents a first frame beam heat exchange receiving two heat exchange tubes,

figure 3 - is a view of the first frame of Figure 2 alone,

figure 4 - is a partial view in section of a first frame showing a step for the flow of a coating which melts during brazing,

figure 5 - is another perspective view of a stack of first frames and frames of the second heat transfer core of the heat exchanger of Figure 1,

figure 6 - is a partial view in perspective showing a reservoir for flowing a coating which melts during brazing provided on a second frame, and

figure 7 - is a sectional view of a second side frame having a reservoir on each face.

On these drawings, the substantially identical components bear the same references.

The following embodiments are examples. Although the description refers to one or more embodiments, this does not signify necessarily that each reference relates to the same embodiment, or that the features are applicable only to a single embodiment. Simple features of different embodiments may also be combined to provide further 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 Figures. This arrangement corresponds to the inverted arrangement of the elements in the installed state in a motor vehicle in particular.

With reference to Figure 1, a heat exchanger 1 as for a motor vehicle, to perform a heat exchange between at least a first fluid and a second fluid.

The first fluid can enter the heat exchanger 1 as a gas and the second fluid in liquid form.

It is in particular a heat exchanger assembled by brazing. For this purpose, the heat exchanger 1 has at least partially, it is to say on at least certain elements or parts, a coating melts for securing the joint elements of the heat exchanger when the brazed joint, as this will be detailed later.

The heat exchanger 1 according to the invention is particularly adapted to circulate at least one fluid having a high working pressure, in particular greater than lOObars.

For example the first fluid is a refrigerant fluid intended to flow high pressure such as co2, also referred to as the nomenclature r744 industrial.

The heat exchanger 1 can in particular be a gas cooler in which the refrigerant fluid such as co2 is cooled by a second fluid for example in liquid form, such as cooling fluid comprising a mixture of glycol water.

The second fluid such that the cooling liquid can also be cooled by the first fluid such as co2, such a heat exchanger is then commonly referred to as "waste water chiller" in English.

The heat exchanger 1 includes a heat transfer core 3 for heat exchange between the first fluid and the second fluid. In the illustrated example, the heat transfer core 3 has a substantially parallelepipedic general shape.

The circulation of the first and second fluids is advantageously carried out in a counter-flow heat transfer core 3.

The supply and discharge the fluid into the first heat transfer core 3 or beam heat exchange 3 is shown schematically by way of example by the arrows ISV for introduction and FLO evacuation.

Similarly, the introduction of the second fluid in the heat transfer core 3 and discharge of the fluid out of the second heat transfer core 3 is shown schematically by way of example by the arrows f2i for introduction and f2o for evacuation.

Finally, the heat exchanger 1, and more precisely the heat transfer core 3, may be configured to circulate in at least two passes of one of the fluids, or even of the two fluids, as will be described in more detail subsequently.

An example of flow of two fluids counterflow and two pass is illustrated schematically by arrows fl in Figure 1 f2.

More specifically, the heat transfer core 3, comprises a plurality of heat exchange tubes 5 (see Figure 2) stacked to define alternately first flow channels 7 for the first fluid in the heat exchange tubes 5 and 9 of the second channels for circulating the second fluid between the heat exchange tubes 5.

The heat exchange tubes 5 may be constructed as flat tubes, advantageous in terms of the space.

The flat tubes 5 have a general shape that is substantially rectangular, with a length for example of the order of 32 mm and a thickness of the order of mm.

The thickness is herein considered in the height direction of the heat transfer core 3, it can be also of 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 flow channels 7 for the first fluid, in particular micro-circulation channels 7 for the first fluid.

The first channels or micro-channels 7 extend here substantially longitudinally, as into substantially straight or "I-". The first channels or micro-circulation channels for the first fluid 7 allow the flow of the first fluid respectively extend along a direction parallel to the longitudinal direction of the heat exchange tubes 5.

The first fluid may follow a flow pass said flow in "the I" but also a two-pass circulating said flow "U-shaped" as will be described subsequently.

Similarly, the second channels 9 for circulating the second fluid may be shaped to permit a flow pass said flow in "the I" but also a two-pass circulating said flow in "U-shaped" as will be described subsequently.

Tab delimited 11 of the flow of the second fluid are advantageously disposed in the second flow channels 9, thereby enhancing the heat exchange between the two fluids.

The turbulators 11 can be carried by a member 12 separate heat exchange tubes 5. alternatively, turbulators 11 may be formed on the heat exchange tubes 5, e.g. by deformations such as corrugation of the heat exchange tubes 5 which project into the second circulation channels 9 for the second medium.

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

In one embodiment, the heat transfer core 3 comprises an alternating stack of first frames of second frames 13 and 15. At least some second frames 15 form the spacer. The stack is here substantially vertically.

Each first frame 13 is adapted to receive at least one heat exchange tube 5 and the assembly forms a stage of the heat exchange bundle 3. may be referred to the first frames by frame-tube 13.

Each second frame 15 may receive turbulators 11 and this assembly forms another stage of the heat transfer core 3.

These two sets or stages are repeated as many times as necessary according to the available space and performance to be achieved. The first frames 13 and the second frames 15 are described in more detail subsequently.

By way of example, plates closures 17, 18 (see Figure 1), in particular at least one closure plate 17 lower and at least one closure plate 17, top 18, can be arranged on either side of the stack of the primary frames 13 and second frames 15, so as to close the heat transfer core 3.

By referring to Figure 1, the heat exchanger 1 further comprises at least one header box 19 of first fluid arranged in fluid communication with the first flow channels 7.

The collector box 19 as exemplified is arranged on a top closure plate 18 disposed at the top of the heat transfer core 3.

The heat exchanger 1 further comprises at least two ports 21 inlet and fluid outlet for introduction and removal of the second fluid. In this example, the two connection pipes 21 are arranged on the same top closure plate 18 that the collector 19 for the first fluid.

Of course, in an embodiment not shown, may be provided to arrange the two connection pipes 21 on the bottom plate 17.

In yet another embodiment not shown, there may be provided separately arranging the pipes 21 with a connecting pipe 21 on the top plate 18 and the other branch 21 on the bottom plate 17.

In particular, the collector box 19 may be arranged heat transfer core 3 and the tubes 21 may be arranged on the other side of the heat transfer core 3, thereby providing a counter-current flow of the two fluids.

According to the arrangement shown in Figure 1, the collector box 19 is arranged to the left while the pipes 21 are arranged at right.

With reference to Figures 2 to 4, is now describes in more detail the first frames 13 receiving heat exchange tubes 5.

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

The first frames have 13:

two opposite edges 13 Α, 13b (see Figures 2 and 3) extending perpendicularly to the direction of the first flow channels 7 of the first fluid, i.e. here perpendicularly to the longitudinal direction of the heat exchange tubes 5, and

two other opposing edges 13c, 13d extending parallel to the direction of the first flow channels 7 of the first fluid, i.e. here parallel to the longitudinal direction of the heat exchange tubes 5.

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

two opposite edges 13 Α, 13b extending perpendicular to the general direction of flow of the first fluid, and

two other opposing edges 13c, 13d extending parallel to the general direction of flow of the first fluid.

The general direction of flow of the first fluid refers to the direction of flow in "the I" in the case of a flow of the first fluid in one run, or the direction of the branches of the "U-shaped" in the case of a two-pass flow of the first fluid.

In the examples shown, the first frames 13 are shaped substantially rectangular 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, forming small sides, extending in the width direction, substantially perpendicular to the direction of flow of the first fluid.

However, in other embodiments, would be anticipated of the frames having a general shape that is not rectangular, e.g. elliptical, or diamond-shaped.

The longitudinal axis of the primary frames 13 and of the heat exchange tubes 5 here is coincident.

These first frames 13 have a same thickness as the heat exchange tubes 5 they receive, especially to twist a few millimeters, e.g. twist of 1 mm.

As previously, the thickness is viewed from the direction of the height of the heat transfer core 3, it can be also of the height of the primary 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 superimposition of different frames 13, 15.

In one embodiment not shown, each first frame 13 may be adapted to receive a single heat exchange tube 5 for circulation of the first fluid in one run. For this purpose, each first frame 13 has a housing 130 for receiving a heat exchange tube associated 5.

According to the embodiment illustrated in Figures 2 and 3, each first receiving frame 13 is adapted to receive two heat exchange tubes 5.

The heat transfer core 3 then has two rows of heat exchange tubes 5: heat exchange tubes of the first 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 flow of the first fluid in two passes.

The heat transfer core 3 thus has at least one turning region of the first fluid, it is to say allowing the first fluid circulated in a heat exchange tube 5 to flow to another heat exchange tube 5, namely the heat exchange tube 5 adjoining received in the same first frame 13. Of course, there may be more than two heat exchange tubes 5 for a flow of the first fluid in more than two passes in a first frame 13.

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

To allow the flow of the first fluid in the heat transfer core 3, the first frames 13 includes means for providing fluid communication of the first channels 131 7 circulation of the heat exchange tubes 5 with the header box 19.

The means for providing fluid communication 131 of each first frame 13 are thus arranged in fluid communication with the means for providing fluid communication 131 other first frames 13 of the heat transfer core 3 and with the collector box 19.

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

Thus, first communication means 131 provide for fluid communication of the first heat exchange tubes 5 or otherwise of a first row of first heat exchange tubes 5 with the collector box 19. And, second communication means 131 provide for fluid communication of the second heat exchange tubes 5 or in other words the second row of second heat exchange tubes 5 with the collector box 19.

According to the illustrated example, the first frames 13 each have a predefined number of recesses 131 forming the means for providing fluid communication, in which the ends, in particular the longitudinal ends, of the heat exchange tubes 5 emerge. Of course, the number of recesses 131 is adapted depending on the number of first channels 7 circulation of the heat exchange tubes 5.

These recesses 131 are herein provided on two opposite edges 13 Α, 13b of first frames 13 which are facing the ends of the heat exchange tubes 5. this is dependent side edges 13 of the primary frames.

The first frames 13 are arranged such that their recesses 131 are in fluid communication with the recesses 131 other first frames 13. Here, the recesses 13 131 of the primary frames are aligned in the height direction of the heat transfer core 3. further, on a side of the primary frames 13, the recesses 131 are aligned with the collector box 19.

According to the illustrated embodiment, at least one lateral edge 13 Α, 13b of a first receiving frame 13, arranged in relation to one end of a heat exchange tube 5, is formed in a pattern defining a succession of undulations.

The arches are advantageously arranged along the entire width of the lateral edge 13a, 13b facing ends of the heat exchange tubes 5 accommodated in the same first frame 13.

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

The term arch the assembly formed by a roof of arch 132 connects two feet arch 133. In this succession of arches, two vaults arch 132 adjacent one another are connected by a common foot arch 133.

According to the illustrated example, a recess is defined by an archway 131, i.e. each recess 131 is formed between two adjacent arched legs 133 and is formed by these two feet arched vault of arch 133 and 132 connecting them.

When a heat exchange tube 5 is arranged in the housing 130 of a first frame 13, the remaining space between one end of the heat exchange tube 5 and a vault arch 132 defines a through aperture for providing fluid communication. By way of non-limiting example, the diameter of a through-opening is of the order of 0.5 mm.

Further, each first frame 13 advantageously comprises at least one stress-absorbing area on at least one side edge 13a, 13b in relation to one end of a heat exchange tube 5.

Such a stress-absorbing region is able to withstand the mechanical stresses, particularly due to pressure. The stress-absorbing areas may be performed by a predetermined number of legs stress-absorbing formed on at least one side edge 13 Α, 13b of a first frame 13 in respect to one end of a heat exchange tube 5.

These stress-absorbing legs extend towards the end of the heat exchange tube 5.

In the illustrated example, the feet of undulations 133 provide this stress-absorbing leg.

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 feet of the arches still permit 133 define zones of brazing with the second frames 15 as will be described subsequently.

Furthermore, to allow the flow of the second fluid in the heat transfer core 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 formed with at least one snare 134 which when a heat exchange tube 5 is arranged in the first frame 13 defines an opening therethrough allowing flow of the second fluid.

By way of illustration, is shown in Figures different embodiments handles 134, in particular Figure 1, illustrates a first exemplary embodiment handles 134 of substantially rounded shape, while Figures 2, 3 and 5 illustrate a second example embodiment handles 134 whose contour is shaped more straightened. Of course any other form handles 134 may be contemplated.

The bails 134 define the position of the guides for the passage of the second fluid. By way of example, this through opening has a diameter of around 2 mm.

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

The bails 134 of each first frame 13 are arranged flush to the snares 134 other first frames 13 of the heat transfer core 3 so as to allow the flow of the second fluid through the bundle 3.

Further, each first receiving frame 13 present according to the embodiment illustrated in Figures 2 and 3, at least one partition wall which separates the first 135 receiving frame 13. This partition wall 135 is here arranged in the prolongation of a foot arch 133.

In the illustrated example, each first receiving frame 13 has a separating partition 135, for example substantially central, which separates the first receiving frame 13 130 into two housings for receiving a heat exchange 5.

The partition 135 is therefore arranged between two heat exchange tubes 5 when they are inserted in the first frame 13. The partition wall 135 extends in this example along the entire length of the heat exchange tubes 5 received in the first frame 13.

The partition 135 of a first frame 13 may be formed in one piece with the first frame 13. Such a first frame 13 can be performed by cutting deep-drawing in a simple manner.

An enlarged portion of a first frame 13 is shown in Figure 4.

As said previously the heat exchanger 1 is particularly attached by brazing. For this purpose, provided that the elements of the heat transfer core 3, and in particular the first 13 and second 15 frames, at least partially comprise a coating adapted to melt when the assembly passes into the furnace for brazing and to migrate into interfering clog the clearances between the parts of the heat exchanger 1.

The coating is commonly referred to as "cladd" in the field of brazing metal pieces, in particular aluminum. In particular, the coating is added on the core parts, such that the first frames 13 and second frames 15, during manufacture, for example by cold rolling. It may be by way of 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 sufficiently small not to weaken the elements of the heat transfer core 3, especially the first frames 13 and the second 15, after brazing.

The first frames 13 each have at least one recess 139 at an inside corner receives a wedge of a heat exchange tube 5, it is to say on a corner of the inner edge of a first frame 13, which is in relation to a heat exchange tube with 5 when the latter is arranged in the first receiving frame 13.

Such a step 139 is provided to permit flow of the coating during soldering of the heat exchanger 1, thereby preventing the coating into a plugging the first channels or micro-circulation channels 7 of the heat exchange tubes 5.

Of course, the size of this removal of rocks 139 takes into account a compromise not to weaken the first frame 13 while which can collect a sufficient amount of the coating have migrated during brazing.

In one particular example, the width of this offset 139 is substantially equal to the width of a groove 154 provided for a like purpose on a second frame 15 as described subsequently.

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

In addition, the one or more setbacks 139 are arranged close to the means for providing fluid communication 131.

In addition, as best seen in Figure 4, as exemplified in which at least one edge of a first frame 13 is formed with a succession of undulations, at least one step 139 is formed in the extension of an archway extrêmale, it is to say the first or last arch of the succession of undulations.

With reference to Figures 5 and 6, is now describes the second frames 15.

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 called frames that turbulators or frames holder turbulators.

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

two opposite edges extending parallel to the direction of the first flow channels 7 of the first fluid, i.e. here parallel to the longitudinal direction of the heat exchange tubes 5, and

two other opposing edges extending perpendicular to the direction of the first flow channels 7 of the first fluid, i.e. here perpendicularly to the longitudinal direction of the heat exchange tubes 5.

May also be defined the second frames 15 relative to the general direction of flow of the first fluid, i.e. that the second frames 15 have:

two opposite edges extending parallel to the general direction of flow of the first fluid, and

two other opposing edges extending perpendicular to the general direction of flow of the first fluid.

Further, according to the described embodiments, another alternative is to define the second frames 15 relative to the general direction of flow of the second fluid flowing in the opposite direction of the first fluid, i.e. that the second frames 15 have:

two opposite edges extending parallel to the general direction of flow of the second fluid, and

two other opposing edges extending perpendicular to the general direction of flow of the second fluid.

The general direction of flow of the second fluid refers to the direction of flow in "the I" in the case of circulation of the second fluid pass, or the direction of the branches of the "U-shaped" in the case of circulation of the second fluid in two passes.

In the illustrated example, the second frames 15 are generally similar to the first frames 13, herein substantially rectangular.

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

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

In particular, the outer contours of the primary frames 13 and second frames 15 are substantially identical so that the stack alternate first and second frames 15 frames 13 forms a block.

More particularly, each second frame 15 defines an inner width and an inner length. The term "internal width", the width defined between the inner walls of the opposite longitudinal edges.

Similarly, the term "internal length", the length defined between the inner surfaces of the opposed side edges. Further, the side edges of the second frames 15 may be slightly larger than the side edges of the primary 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 side edges of the second frames 15. The second frames 15, 15' therefore define an internal length L of less than an inner length defined by the interior of the primary frames 13.

The second frames 15 have a thickness which is of the order of a few millimeters, for example of the order of 0.5 mm to 4 mm, preferably of the order of 2 mm. The thickness is herein considered in the height direction of the heat transfer core 3, it can be also of the height of the second frames 15. In other words, it is the thickness in the stacking direction of the frames 13, 15, 15 '.

Similar to the first frames 13, the second frames 15 may be cut in one piece by stamping.

A plurality of second frames 15 said spacers, are arranged between two first frames 13 receiving heat exchange tubes 5, thereby defining the pitch between two stages of heat exchange tubes 5.

In one non-limiting embodiment, the heat transfer core 3 can further comprise a second end frame (not shown) optionally arranged between a first frame 13 and a closure plate 17, particularly the bottom closure plate 17. Such a second end frame may be provided for reasons of mechanical strength.

Each second frame 15 may be configured to pass a flow of the second fluid. For this purpose, each second frame 15 defines a second circulation channel 9 for the second medium. The second circulation channel 9 extends into substantially as herein "the I".

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

For this purpose, the second frames 15 each comprise a bar 150 arranged inside the respective second frame 15 so as to separate two passes for circulating the second fluid. It is therefore an inner strip 150.

In the illustrated example, the bar 150 as a result of the second circulation channel 9 substantially "U-shaped".

Of course, would be anticipated circulation of the second fluid into more than two passes in a second frame 15 and therefore more than one bar 150 inside the second frame 15 that would be, by way of non-limiting example, and oppositely disposed offset relative to each other.

The bar 150 extends within a second frame 15. The bar 150 thereby extends in this example substantially parallel to the longitudinal edges of the second frame 15.

For this purpose, 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 the second frame 15 toward the opposite side edge but without reaching the opposite side edge.

The bar 150 is therefore integral with a lateral edge of the second frame 15 and protrudes with its free end toward the internal space of the second frame 15 toward the opposite side edge, leaving a gap.

The inner strip 150 thereby extends from a side edge of a second frame 15 over a length the L less than the internal length L of the second frame 15.

The inner strip 150 does not extend over the entire width of the second frame 15 engine. More specifically, the inner strip 150 has a width smaller than the inner width of the second frame 15.

This defines on each side of the bar 150, the inlet and the outlet of the flow path for the second fluid. The bar 150 may also be termed the tongue. Further, the bar 150 is substantially 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 at 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 equal size.

Advantageously, the inner strip 150 extends a length the L at least equal to half the internal length L of a second frame 15.

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

Further, in case the second frames 15 comprising such a bar inner 150 are stacked together with first frames 13 each receiving a single heat exchange tube 5, the heat exchange tubes 5 or mono-tube received in the first frames 13 may rest on the webs 150 of the second frames 15 in respect to.

Alternatively, the inner bridges 150 second frames 15 are facing partitions 13 135 of first frames made according to the embodiment illustrated in Figures 2 and 3.

Complementarily to the first receiving frames 13, the second frames 15, particularly the second spacer frames 15, 151 have guides for passage of the first fluid for its flow in the stack receiving frames of the first and second frames 13 15, in particular spacers. The guides 151 are here designed as through-passing holes 151 arranged in alignment recesses 131 for providing fluid communication of the first receiving frames 13, defined herein by the succession of undulations.

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

Of course, the number of through-holes through 151 is adapted depending on the number of recesses 131 and thus the number of first channels 7 circulation of the heat exchange tubes 5.

The second end frame, when present, is constructed similarly to a second intermediate frame 15, to the difference that the second end frame has no openings 151 of through-passages for the passage of the first fluid.

Further, the second frames 15 each have means for providing fluid communication of the second channels 152 circulation 9 between them on the one hand and with the tubules 21 for the second fluid on the other hand.

According to the illustrated example, the second frames 15 each have a predefined number of through openings 152 for providing fluid communication. The through openings 152 are here arranged on the longitudinal edges of second frames 15 and are aligned to each other in the height direction of the heat transfer core 3. the through openings 152 open respectively to the interior of a second frame 15.

In addition, in the example shown in Figures 1 and 5, the through openings 152 are arranged on a same side of a second frame 15 in the longitudinal direction, it is to say here to right or left, complementarily to the arrangement of pipes 21 on a same side of the heat transfer core 3, here to the right with reference to the arrangement shown in Figure 1.

The through openings 152 define a fluid inlet 152 on the interior of the second frame 15 on one 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 by means of which the through-openings 152.

The bails 153 of second frames 15 are formed similarly to the bights of the primary frames 13 and 134 are aligned with these handles 134 that allow passage of the second fluid through the heat transfer core 3.

By way of illustration, is shown in Figures different embodiments handles 153, in particular Figure 1, illustrates a first example embodiment of the bends 153 of substantially rounded shape, while Figure 5, illustrates a second example embodiment of the bends 153 whose contour is shaped more straightened.

Of course, when bail 134 of the primary frames 13 are carried out according to the first example embodiment, the bails 153 of second frames 15 are similarly formed according to the first example embodiment.

And, when bail 134 of the primary frames 13 are designed according to the second example embodiment, the bails 153 of second frames 15 are similarly formed according to the second example embodiment. Of course any other form handles 153 may be contemplated.

Among the two bights 153 of second frames 15, the opening bounded by a first lug is arranged in fluid communication with a first pipe 21 and the opening delimited by a second handle is fitted in fluid communication with a second manifold 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 primary frames 13 and the side edges of the second frames 15 are intended to be assembled by brazing with the feet arch 133 provided on the side edges 13 of the primary frames.

In one embodiment, for brazing, the second frames 15 each have at least one reservoir 154, best seen in Figure 6, adapted to collect the coating or "cladd" during soldering of the heat exchanger 1.

Each reservoir 154 is herein arranged on a lateral edge of the second frame 15. Advantageously a reservoir 154 is provided on each side edge of a second frame 15. Each reservoir 154 is then situated facing a side edge 13a, 13b of a first receiving frame 13 leading to an end 50, 52 of a heat exchange tube 5.

Thus, when the brazed joint of the heat exchanger 1, the coating on the first frames 13 and the second frames facing 15, bottom and migrates to plug the clearances between the parts of the heat exchanger 1 and comes to flow into the tanks 154, thereby preventing the coating has melted and migrated into a plugging the first channels or micro-circulation channels 7 of the heat exchange tubes 5.

Advantageously, the at least one reservoir 154 are provided on each side of a second frame spacer 15 arranged between two first frames 13.

Optional in the case where there is provided a second end frame, the at least one reservoir 154 may be arranged on only one side of this second end frame, namely on the side opposite to a heat exchange tube 5, and not on the opposite side of the second end frame, in relation to a closure plate each reservoir 154 may be performed by local reduction of material of a second frame 15.

The depth the P a reservoir 154 must be selected so large manifold the coating, which is for example of the order of 5% to 10% of the material of the second frame 15, and sufficiently small as not to weaken the mechanical strength of the second frame 15.

By way of non-limiting example, the reservoir 154 may have a depth the P of the order of 0.5 mm.

The particular example illustrated, the reservoir 154 is formed as a groove 154 extending substantially perpendicular to the direction of flow of the first fluid in the heat exchange tubes 5, herein in the width direction of a second frame 15.

Specifically in this example, the reservoir 154 extends opposite the end of a heat exchange tube 5, i.e. over the entire width of a tube or of each heat exchange tube 5.

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

Furthermore, the second frames 15, especially the second spacer frames 15, may also be configured to fluidly connect two heat exchange tubes 5 accommodated in the same first frame 13 according to the embodiment of the primary frames 13 illustrated in Figures 2 and 3.

This are therefore the second frames 15 which allow the flow in at least two passes of the first fluid in each first frame 13, while ensuring good mechanical stability of the primary frames co2 13 because of the high pressure flowing through the heat exchange tubes 5.

More specifically, each second frame 15, especially intermediate, advantageously has at least one orifice turning 155 (see Figure 5) which is in fluid communication with both a first and a second fluid communication means 131, herein a first and a second recesses 131, of the primary frames 13 on either side of the second frame spacer 15.

Thus, each orifice turning 155 is arranged between two adjacent heat exchange tubes 5 received in first frame 13 and in flow communication with both heat exchange tubes 5.

Thus, the first fluid which opens into a first heat exchange tube 5 is turned into the port reversing 155 then flows to a second heat-exchanger tube 5.

The two rows of heat exchange tubes 5 arranged in the first frames at an end 13 then communicate via ports 155 provided on reversing the second frames 15, such as spacers.

Each port 155 is herein provided between turning passage openings through 151 on at least one side edge of each second frame 15, in particular spacer.

Each orifice turning 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 orifice turning 155 has a longitudinal shape extending perpendicularly to the longitudinal edges of the second frame 15, in particular spacer.

In particular, each orifice 155 turner arranged to face a first receiving frame 13, extends on either side of the partition wall 135 of this first receiving frame 13.

For example, turning the port 155 is substantially oblong in shape.

Furthermore, turning the port 155 is sized to have a section for inverting the first fluid at least equal to the flow area of a heat exchange tube 5.

Further, preferably, there is complementarily circulation in two passes, so-called "U-shaped", of the first fluid in a first receiving frame 13 according to the second, third or fourth embodiment, two pass and circulation, so-called "U-shaped" of the second fluid in a second frame 15 according to the second embodiment. The heat exchanger 1 is then double circulation "U-shaped".

Thus, the heat exchanger 1 comprises a stack of first frames 13 receiving the heat exchange tubes 5 and advantageously of second frames 15 capable of receiving turbulators 11. It is a simple element may be assembled easily, by brazing.

The kinks 139 to the interior corners of the primary frames 13 form a flow passage for the coating when the latter melts and migrates during brazing, thereby avoiding that they will clog the first channels or micro-channels 7 circulation for the first fluid in the heat exchange tubes 5.