FR3066013A1 - HEAT EXCHANGE TUBE AND HEAT EXCHANGER HAVING AT LEAST ONE SUCH TUBE - Google Patents

Abstract

The heat exchanger tube has two main walls connected by end edges, so as to form an internal channel for the sealed circulation of a fluid. The heat exchanger tube has an inner spacer housed within the inner channel. Said inner spacer has at least one end portion facing one of the end edges of the tube. Said end portion is folded on itself so as to at least double an interlayer thickness facing said end edge of the tube.

Description

HEAT EXCHANGE TUBE AND HEAT EXCHANGER COMPRISING AT LEAST ONE SUCH TUBE

The present invention according to its various aspects relates to the field of heat exchangers and in particular heat exchangers placed on the front face of a motor vehicle.

In motor vehicles, heat exchangers interact with a fluid circulation loop, in order to generate a heat exchange between air outside the vehicle directed to pass through these heat exchangers and the fluid. It can be a heat transfer fluid, a refrigerant, or a gaseous fluid such as an intake air flow for an internal combustion engine.

These heat exchangers can consist of radiators, condensers or supercharged air coolers. In these heat exchangers, several tubes are stacked on top of each other and spacers can be arranged between them. The fluid circulates inside the tubes and exchanges calories with the outside air which passes through the heat exchanger, the spacers arranged between the tubes participating in the increase in the heat exchange surface.

These heat exchangers are arranged in a conventional manner on the front face of motor vehicles, in order to best capture the outside air, upstream of the engine which is arranged in the engine compartment of the vehicle.

The position on the front face of these heat exchangers exposes the vehicle's most forward heat exchanger to the projection of debris or gravel which can damage or even pierce the tubes inside which the fluid circulates. More specifically, the tubes of the heat exchanger located furthest from the vehicle are arranged transversely to the direction of movement of the vehicle, in a flat and horizontal arrangement. As a result, the tubes of this heat exchanger located furthest forward of the vehicle are exposed to gravel and projections at their edge facing the front of the vehicle.

In order to protect these heat exchangers, it is known to place in front of them a protective grid which can retain gravel or any other projectile and thus avoid impacts on the tubes of the exchangers. It is for example known from document FR3035956 to have a protective grid upstream of the heat exchanger or exchangers of the motor vehicle, by clipping this grid onto the heat exchanger.

If such an arrangement allows appropriate protection of the heat exchangers, it should however be noted that the presence of the grid generates on the one hand a longitudinal bulk penalizing in this area where the available space is limited, and a cost.

Thus, the aim here is to propose an alternative to the known protection devices for heat exchangers, which makes it possible to ensure the mechanical strength of the tubes of the heat exchanger which is likely to be struck by gravel or other projectiles, which is not very expensive and space-saving. The first object of the invention is a heat exchanger tube comprising two main walls connected by end edges, so as to form an internal channel for the sealed circulation of a fluid, the heat exchanger tube comprising a internal insert housed inside the internal channel. The internal interlayer has at least one end portion facing one of the end edges of the tube, and this end portion is folded back on itself so as to at least double a thickness of opposite interlayer said end edge of the tube.

According to different features of the invention, taken alone or in combination, provision may be made for: - the end portion is positioned against the internal face of the end edge of the corresponding tube; - the internal interlayer is brazed with the tube, so that the end portion is in contact and integrally connected with the internal face of the end edge of the corresponding tube; - the end portion of the internal interlayer takes the form of a strip extending over the entire length of the end edge of the corresponding tube; the length is defined as a function of the direction of circulation of the fluid inside the tube; - the end portion is folded back on itself towards the inside of the tube; in other words, the end portion is folded back on itself so as to form a base part, arranged in direct extension of the central portion of the inner interlayer, and a folded part, said folded part being turned towards the inside of the internal fluid circulation channel, so that the end edge of the tube, the base part of the internal interlayer and the folded part of the internal interlayer; - the end portion is folded back on itself towards the end edge of the tube; in other words, the end portion is folded back on itself so as to form a base part, arranged in direct extension of the central portion of the inner interlayer, and a folded part, said folded part being turned towards the periphery of the internal fluid circulation channel, that is to say towards the end edge of the tube, so that are stacked one against the other, and in this order, the edge of end of the tube, the folded part of the internal interlayer and the base part of the internal interlayer; - the internal interlayer is brazed with the tube so that the end portion is in contact and integrally connected with the internal face of the end edge of the corresponding tube and so that the folded part and the base part of this end portions are in contact with one another and are integrally linked; - the internal interlayer is formed by a sheet folded to be across the internal channel; - The sheet may in particular have a wavy shape or a crenellated shape; - The folded sheet has a central portion and at least one end portion arranged in the extension of the central portion to be opposite an end edge, the central portion having vertices arranged against the main walls of the tube. The invention also relates to a heat exchanger comprising a plurality of tubes stacked one above the other among which at least one of the tubes conforms to what has just been described above. The heat exchanger may in particular include spacers arranged between the tubes and configured to allow passage to air. The invention also relates to a motor vehicle comprising on the front face a heat exchanger as it has just been presented, and in which the heat exchanger is configured so that the end edge of the tube, against the internal face of which is positioned the end portion of the internal interlayer folded back on itself, is oriented towards the front of the vehicle. Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several exemplary embodiments given by way of non-limiting indication with reference to the appended schematic drawings on the other hand, in which : - Figure 1 illustrates a heat exchanger, comprising a stack of tubes extending respectively between two manifolds and configured to interact with a fluid circulation loop not shown here, on the front of a motor vehicle; - Figure 2 illustrates a detail of the heat exchanger, without manifold in order to make more particularly visible a stack of heat exchange tubes inside which the fluid circulates, spacers being arranged between each of the tubes for be crossed by air with which the fluid exchanges calories; - Figure 3 illustrates a heat exchange tube seen in section along the cutting plane P illustrated in Figure 2, and making visible the presence of an internal interlayer arranged inside the tube and the particular shape according to a first embodiment of the invention of the end portions of this internal insert; - Figure 4 illustrates a detailed view of an end edge of the heat exchange tube of Figure 3, making in particular more visible the particular shape according to the first embodiment of the invention of a portion d end of the internal interlayer; and - Figure 5 illustrates a detail view similar to that of Figure 4, making visible the presence of an internal insert arranged inside the tube and the particular shape according to a second embodiment of the invention. an end portion of this internal insert.

A heat exchanger according to one aspect of the invention comprises at least one fluid circulation tube inside which an internal spacer is configured to form a local allowance at the edge of the tube exposed to the projection of gravel during rolling. of the vehicle, that is to say the edge of the tube facing the front of the vehicle when the heat exchanger is mounted on the vehicle.

In Figure 1, there is illustrated a heat exchanger 1 comprising a plurality of tubes 2, at least one of which conforms to what has just been presented. The heat exchanger 1 more precisely comprises a plurality of tubes 2 extending in a first direction, or longitudinal direction L, between two manifolds 4, 6 configured to be fluidly connected to a fluid circulation loop of a vehicle automobile, not shown here.

A first manifold 4 forms a fluid intake chamber, via an inlet pipe 5, and distribution of this fluid in each of the tubes, and the second manifold 6, opposite, forms a collection chamber fluid having passed through the pipes and exhaust via an outlet pipe 7.

Each tube 2 is hollow to form an internal circulation channel 8 of fluid from one manifold to the other in the first direction, or longitudinal direction L, and as will be described in more detail below, each tube 2 has an internal insert 10 arranged in the internal circulation channel 8.

The tubes 2 are stacked one above the other in a second direction, or vertical direction V, perpendicular to the first direction. At at least one vertical end of this stack, in particular visible in FIGS. 1 and 2, a structure plate 12 is arranged to participate in the stiffening of the assembly and / or facilitate the fixing of the exchanger in the front compartment of the vehicle.

The tubes are stacked with a spacing between two neighboring tubes in order to allow an air passage through the exchanger in a third direction, or transverse direction T. An air flow F, and more particularly an external air flow to the vehicle, can thus pass through the heat exchanger between the tubes. In contact with the external face of the tubes, a heat exchange takes place between the air passing through the heat exchanger transversely at a certain temperature and the tubes 2 traversed by the fluid longitudinally and brought in this way by thermal conduction at a certain temperature.

In order to increase the heat exchange surface, the spaces between the heat exchange tubes 2 are occupied by spacers 14, here taking the form of corrugated sheets. These spacers are arranged in the first direction between the manifolds and are more particularly visible in Figure 2. The shape in periodic reliefs, for example sinusoidal or in slots, spacers is defined to allow the passage of air without creating too much high pressure losses while increasing the heat exchange surface.

We will now describe in more detail a heat exchange tube, with particular reference to Figures 2 and 3.

The heat exchange tube 2 has an oblong section internally delimiting an internal circulation channel 8 sealed with a fluid, the channel being delimited by two main walls 16, 18 planar and parallel to each other, connected by edges of end 20.

The heat exchange tube 2 is advantageously obtained by rolling a sheet of sheet metal, so that the end edges 20 forming the connecting walls of the main walls have a curved shape, curved towards the outside of the internal channel of circulation defined inside the tube.

The heat exchange tube 2 further comprises an internal spacer 10 housed inside the internal circulation channel 8 and formed of a sheet bent to be across the passage of the fluid and to increase the surface of exchange of heat. The internal interlayer 10 thus defines a plurality of subchannels 80 for fluid circulation. Here, the inner interlayer has a wavy shape, of the type of a sinusoid, but it is understood that without departing from the context of the invention, the inner interlayer could have other shapes and for example a crenellated shape.

In the example illustrated in FIGS. 2 and 3, the heat exchange tube, and in particular the main walls 16, 18, is arranged so as to have a section in the form of B. In other words, in the example illustrated , once the tubes are folded and then cut into sections, the thin wall of these generally has a flattened B-shaped cross section, that is to say, with a first main wall 16 which forms a flat base part and which is extended, by means of the two connecting walls forming the end edges 20, by two parts which together form the second main wall 18. These two parts extend parallel to the first main wall in approximation one on the other and ending in adjacent end legs 22, turned perpendicularly to the first main wall 16. Two internal longitudinal and parallel spaces, corresponding to the loops of B, are then defined by pa rt and other of the junction zone of the two parts of the second main wall 18. The internal interlayer 10 is arranged over the entire transverse dimension of the tube, that is to say the dimension of an edge of end 20 to the other, with a flat connecting part fitting into a gap left between the adjacent end legs 22 and the first main wall 16 of the tube. The internal interlayer 10 has end portions 24, arranged transversely on either side of a central portion 26, in contact with the internal faces of the end edges 20 of the tube, the central portion 26 having, by its wavy or crenellated shape, vertices arranged against the internal faces of the main walls 16, 18 of the tube.

The assembly of the tube is first carried out by rolling the tube in a pre-assembly configuration, that is to say with the legs of adjacent ends leaving sufficient clearance to allow the thickness of the portion to pass central of an internal interlayer. This internal interlayer, folded beforehand to give it its functional form of local reinforcement of the tube against the gravel, that is to say with the end portions folded back on itself, is thus inserted inside the tube. 2.

The assembly of the tube then comprises a step according to which the tube 2 is compressed in order to bring the main walls together, so as to reduce the clearance left between the adjacent end legs and the first main wall, and to pinch the internal interlayer in this way. The compression of the tube 2 then generates the expansion of the internal interlayer towards the end edges and thus ensures the contact of the end portions 24 of the internal interlayer 10 against the internal face of the end edges 20 of the tube.

The plurality of tubes thus formed and other components of the exchanger such as the manifolds are then passed through a brazing oven making it possible to secure, in particular as regards the tubes which are the subject of the invention, the interlayer internal with the internal face of the walls delimiting the corresponding tube, in each zone where the internal interlayer was in contact with the walls of the tube, by means of cladding coatings (clad) provided on the internal interlayer and / or the walls of the tube and whose melting point is slightly lower than that of the material constituting the walls of the tubes and the internal spacers.

We will now describe in more detail the end portions 24 of the inner interlayer 10, arranged at the edge of the central portion 26 in the third direction, that is to say the transverse dimension T of air passage to through the heat exchanger. It is understood that each end portion of the inner interlayer here has the form of a strip extending all along the central portion in the first longitudinal direction L, against the end edge of the corresponding tube.

At least one end portion 24 is arranged in such a way that it creates a local excess thickness forming a reinforcement element of the end edge 20 of the tube against which it is supported.

In Figure 3, the two end portions 24 of the inner tab 10 are arranged in this way, forming reinforcing elements for each of the end edges 20 of the tube. However, provision may be made for only one of the end portions to have such a shape, as long as it is the front edge of the tube exposed to the projection of gravel during the running of the vehicle, that is to say say the edge facing the front of the vehicle. As illustrated in FIG. 4, the front end edge 20, that is to say the one disposed upstream of the air flow F passing through the heat exchanger, should be equipped with this local allowance .

According to a characteristic of the invention, the corresponding end portion 24 of the inner interlayer 10 is folded back on itself so as to double the thickness of the interlayer at its level of contact with the edge of end of the tube. The double thickness end portion is brazed as previously explained while it is in contact with the internal face of the end edge of the tube and in this way forms a local excess thickness SE around the internal fluid circulation channel 8, at the front end edge 20. As illustrated in FIG. 4, the tube thus has, at its front end edge 20 capable of being struck by gravel, thus has a local excess thickness SE which is equal to the sum of the thickness E walls 16, 18, 20 forming the periphery of the tube and twice the thickness e of the folded sheet forming the internal interlayer. It is understood that, in this way, the perforation of the tube by a gravel and the resulting leakage of fluid are avoided, the impact being able to be limited to a notch not opening on the circulation channel internal to the tube.

FIG. 4 illustrates a first embodiment according to which the end portion 24 is folded back on itself towards the inside of the tube 2 and the inside of the internal fluid circulation channel 8. The portion of end 24 comprises a base part 28, disposed in direct extension of the central portion 26 of the internal interlayer 10, and a folded part 30 pressed against the base part 28 to form the double thickness of the internal interlayer. The folded part 30 is turned towards the inside of the fluid circulation channel, that is to say towards a subchannel 80 defined between two branches of the folded sheet forming the internal interlayer 10. In this way, the base part 28 extends between the end edge 20 of the tube 2 and the folded part 30 of the internal interlayer 10.

As it could be described previously, the internal interlayer 10 is brazed with the walls 16, 18, 20 of the tube so that on the one hand the end portion 24 of this internal interlayer is in contact and integrally connected with the internal face of the end edge 20 of the corresponding tube and that on the other hand the folded part 30 and the base part 28 of this end portion 24 of the internal interlayer, formed in the continuity of the sheet used for the realization of this internal insert, are in contact with each other and jointly and severally. This results in a mass of material forming a local excess thickness SE which is particularly resistant to the shocks potentially suffered by the tube during the running of the vehicle.

A second embodiment has been illustrated in FIG. 5 which differs from the first embodiment in that the end portion is folded back on itself this time towards the end edge of the tube. In this second embodiment, the folded part 30 is turned towards the periphery of the internal fluid circulation channel 8, that is to say towards the end edge 20 of the tube. In this way, it is this time the folded part 30 which extends between the end edge 20 of the tube 2 and the base part 28 of the internal interlayer 10.

The above description clearly explains how the invention makes it possible to achieve the objectives which it has set itself and in particular to propose a device for protecting a heat exchanger tube, the protection device being produced by a conformation particular of the tube and in particular of the internal interlayer which it comprises across the internal fluid circulation channel defined by the tube. It should be noted that, in this way, a reinforcement of the tube is proposed by a local extra thickness without modification of the thickness of the walls forming the tube, which could complicate the rolling of the tube to ensure the correct position of this extra thickness, and without adding an external component to the tube, which could complicate the assembly of the heat exchanger and increase its size. The invention takes effect particularly for the local reinforcement of the end edges of the tubes intended to be oriented towards the front of the motor vehicle in which the heat exchanger comprising such tubes is mounted. It is important that the heat exchanger is configured so that the end edge of the tube, against the internal face of which is positioned the end portion of the internal interlayer folded back on itself, is facing forward. of the vehicle. In order to ensure that the reinforced edge of the tubes is correctly oriented, the local allowance may be produced by folding each of the end portions of the inner interlayer against itself against the end edge of the corresponding tube. The invention cannot be limited to the embodiments specifically given in this document by way of nonlimiting examples, and extends in particular to all equivalent means and to any technically operative combination of these means. Of course, the characteristics, the variants and the various embodiments of the invention can be associated with one another, according to various combinations, insofar as they are not incompatible or mutually exclusive of each other. One can in particular imagine variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from state of the art.

Claims (10)

1. Heat exchanger tube comprising two main walls connected by end edges, so as to form an internal sealed circulation channel for a fluid, the heat exchanger tube comprising an internal interlayer housed at the inside the internal channel, said internal spacer having at least one end portion facing one of the end edges of the tube, said end portion being folded back on itself so as to at least double a thickness of interlayer opposite said end edge of the tube. 2. Heat exchanger tube according to claim 1, characterized in that the end portion is positioned against the internal face of the end edge of the corresponding tube. 3. Heat exchanger tube according to claim 1 or 2, characterized in that the end portion of the internal interlayer takes the form of a strip extending over the entire length of the end edge of the tube corresponding. 4. Heat exchanger tube according to one of the preceding claims, characterized in that the end portion is folded back on itself towards the inside of the tube. 5. Heat exchanger tube according to one of claims 1 to 3, characterized in that the end portion is folded back on itself towards the end edge of the tube. 6. Heat exchanger tube according to one of the preceding claims, characterized in that the internal interlayer is formed by a sheet bent to be across the internal fluid circulation channel. 7. Heat exchanger tube according to one of the preceding claims, characterized in that the folded sheet has a central portion and at least one end portion arranged in the extension of the central portion to be opposite a end edge, the central portion having vertices arranged against the main walls of the tube. 8. Heat exchanger comprising a plurality of tubes stacked one on top of the other among which at least one of the tubes conforms to one of the preceding claims. 9. Heat exchanger according to the preceding claim, characterized in that it includes spacers arranged between the tubes and configured to allow passage to air. 10. Motor vehicle comprising on the front face a heat exchanger according to one of claims 8 or 9, characterized in that the heat exchanger is configured so that the end edge of the tube, against the internal face of which is positioned the end portion of the internal interlayer folded back on itself, is oriented towards the front of the vehicle.