FR2945614A1 - TUBE PLATE FOR A HEAT EXCHANGER. - Google Patents

Abstract

The invention relates to a plate (10) of a flat tube (3) for a heat exchanger (1) comprising at least one connecting edge (5) extending along a general extension plane (P2) and having at least one contact area (13). The contact zone (13) extends from the general plane of extension (P2) of the plate (10) in a first direction (x-x) perpendicular to the general plane of extension (P2). The present invention also relates to a flat tube (3) consisting of two plates (10) and a heat exchanger (1) comprising at least two flat tubes (3)

Description

Tube plate for a heat exchanger.

The invention is in the field of heating, ventilation and / or air conditioning of a motor vehicle. It relates to a heat exchanger intended to be housed inside such a facility. It also relates to a tube, in particular a flat tube, integrated in such a heat exchanger. Finally, it relates to a plate constituting such a tube.

A motor vehicle is commonly equipped with a heating, ventilation and / or air conditioning system to modify the aerothermal parameters of a flow of air diffused inside a passenger compartment of the vehicle. The heating, ventilation and / or air-conditioning system consists mainly of a heating, ventilation and / or air-conditioning unit made of plastic and installed under the dashboard of the vehicle. The heating, ventilation and / or air conditioning unit is intended to channel the circulation of the air flow between at least one air intake opening and at least one air distribution opening out of the heating unit, ventilation and / or air conditioning to at least one area of the passenger compartment.

To modify the temperature of the air flow prior to distribution out of the heating, ventilation and / or air conditioning to the passenger compartment, the heating, ventilation and / or air conditioning housing houses at least one heat exchanger . The aerothermal treatment of the air flow, in particular the modification of its temperature, is obtained from a crossing of the heat exchanger by the air flow.

The heat exchanger is, for example, a radiator installed on a cooling circuit of the engine of the vehicle inside which circulates a coolant, or an evaporator installed on an air conditioning loop inside which circulates a refrigerant. The evaporator is able to cool and dehumidify the flow of air while the radiator is able to heat the air flow.

The heat exchanger comprises a bundle of a plurality of flat tubes for circulating the fluid in the heat exchanger. The flat tubes are successively stacked and spaced apart by an interval in which is housed a corrugated spacer. According to various embodiments, the flat tube is formed by the face-to-face assembly of two stamped plates made from a metal strip thus defining a flow conduit in which the fluid passes. The interlayer placed between two adjacent flat tubes promotes a heat exchange between the air flow through the heat exchanger and the fluid, indifferently coolant or refrigerant circulating inside the heat exchanger.

Two adjacent flat tubes are assembled together to provide fluid flow between the two flat tubes and, therefore, throughout the heat exchanger. The assembly of two adjacent flat tubes is achieved by means of brazing joints provided between two respective contact areas of the two adjacent flat tubes.

Each brazing joint consists of a layer of filler metal having a thickness of about 5% to 12%, in particular between 7.5% to 10%, of a thickness of the metal strip in which are made the stamped plates forming the flat tubes. To reduce the mass and / or manufacturing costs of such heat exchangers, it is desired to reduce as much as possible the thickness of the metal strips used for the production of heat exchangers. This results in a reduction in the thickness of the solder joint. Thus, it is common that a solder joint has a small thickness, especially less than 0.03 mm and a short length, especially less than 1.5 mm.

However, the flow of air passing through the heat exchanger is charged with particles, in particular water and / or impurities, for example metal particles. During the passage of the heat exchanger by the air flow, the particles tend to be deposited on the flat tubes and may come into contact with the solder joints. Such a deposit is likely to generate corrosion resulting in weakening and / or damage to the solder joints. In addition, the small thickness of the solder joints makes them very sensitive to corrosion.

Such provisions are unsatisfactory with regard to the preservation of solder joints with respect to corrosion.

The object of the present invention is to provide a corrosion-resistant heat exchanger caused by particles transported by a flow of air passing through the heat exchanger. Another object is to provide a flat tube arranged to form such a heat exchanger arranged to resist such corrosion. A final object of the present invention is to provide a plate used in the production of such flat tubes.

The plate of the present invention is a plate of a flat tube for a heat exchanger. The plate comprises at least one connecting edge comprising at least one contact zone extending along a general extension plane or contact plane. The contact area is intended to be joined by brazing with another contact area of another adjacent plate.

According to the present invention, the contact zone extends from the general plane of extension of the plate or contact plane in at least a first direction perpendicular to the general plane of extension or plane of contact, in particular a length greater than or equal to at 1.5 mm. Alternatively or in addition, the contact zone extends in at least a second direction parallel to the general plane of extension or contact plane.

The contact zone advantageously comprises at least one point of inflection. By this arrangement, the contact zone preferably comprises a first elementary contact zone and a second elementary contact zone which are situated on either side of the point of inflection.

According to a first variant, the first elementary contact zone and the second elementary contact zone are, for example, parallel to one another. A second variant consists in that the first elementary contact zone and the second elementary contact zone are for example still perpendicular to each other. Alternatively, the first elementary contact zone and the second elementary contact zone form between them an angle of between 0 ° and 180 °, preferably between 0 ° and 900. The contact zone is in particular shaped as a baffle.

A flat tube of the present invention consists of at least two plates as previously described. Finally, the present invention is specific to a heat exchanger consisting of at least two flat tubes as described above. Preferably, the flat tubes are assembled by their contact zones by a brazing joint of length greater than or equal to 1.5 mm. Other characteristics and advantages of the invention will emerge on examining the description which follows with reference to the appended drawings, given by way of non-limiting examples, which may be used to complete the understanding of the present invention and the invention. DESCRIPTION OF THE PREFERRED EMBODIMENT AND IF NECESSARY TO CONTRIBUTE TO ITS DEFINITION, IN WHICH: FIG. 1 is a schematic view of a heat exchanger according to the present invention; FIGS. 2 and 3 are diagrammatic views of a flat tube of the heat exchanger according to FIG. 1, and FIGS. 4 to 8 are schematic illustrations of different respective embodiments of contact zones between two adjacent flat tubes according to the present invention. FIG. a schematic view of a heat exchanger 1 according to the present invention. The heat exchanger 1 is indifferently a radiator adapted to be installed on a cooling circuit of a motor of a vehicle, or an evaporator adapted to be integrated in an air conditioning loop. In the first case, the radiator allows the circulation of a coolant, for example a mixture of water and glycol. The radiator is intended to heat an air flow 2. In the second case, the evaporator conveys a refrigerant, such as a halogenated hydrocarbon, especially the fluid known under the name R134A, or a hydrofluoro-olefin refrigerant, especially the fluid known under the name 1234yf. The evaporator is designed to cool the airflow 2.

In both cases, the heat exchanger 1 is intended to be housed inside a heating, ventilation and / or air conditioning system to modify the temperature of the air flow 2 whose circulation is channeled through the heating, ventilation and / or air conditioning system. This change in temperature is obtained from a crossing of the heat exchanger 1 by the air flow 2.

The heat exchanger 1 may also be any other heat exchange device, in particular a condenser, a gas cooler, etc.

The heat exchanger 1 extends over a width L in a first direction x-x, a height H in a second direction y-y and a depth P in a third direction z-z. The first, second and third directions x-x, y-y and z-z form a direct dihedron. According to the exemplary embodiment, the heat exchanger 1 extends globally along a first general extension plane P1 containing the first and second directions x-x and y-y. In FIG. 1, the first general extension plane P1 is parallel to the plane of FIG. 1. The air flow 2 flows perpendicularly to the first general extension plane P1 while passing through the heat exchanger 1. The flow of air 2 therefore circulates along the third direction zz.

The heat exchanger 1 consists of a stack of flat tubes 3 arranged next to each other in the first direction x-x. Each flat tube 3 is formed by an assembly of two metal plates 10.

Each flat tube 3 is provided with at least one communication port 4 for the passage of a first fluid between two adjacent flat tubes 3. Each communication orifice 4 is made in a connecting edge 5 of the flat tube 3. Preferably, the communication orifice 4 is circular in shape. According to the present invention, the connecting edge 5 and the communication port 4 of the flat tube 3 extend along a second general extension plane P2 or P2 contact plane. The connecting edge 5 of the flat tube 3 constitutes a connection zone between two adjacent flat tubes 3. Two adjacent flat tubes 3 are joined to each other by brazing at the connecting edge 5 of each flat tube 3.

The second plane of general extension P2 contact plane P2 is arranged perpendicularly to the first general plane of extension P1.

The flat tube 3 has a plane of symmetry P2 '. The plane of symmetry P2 'is parallel to the second general plane of extension P2 or contact plane P2. An interlayer 6 is placed between two adjacent flat tubes 3 to define a heat exchange surface between the first fluid flowing in the heat exchanger 1 and the air flow 2.

FIGS. 2 and 3 are diagrammatic views of a flat tube 3 constituting the heat exchanger 1 illustrated in FIG. 1. Each flat tube 3 is formed from the assembly, preferably by brazing, of two plates. 10. Each plate 10 is obtained from the stamping of a metal strip so as to form cups and bosses for the circulation of the first fluid. Advantageously, each plate 10 is of generally rectangular shape. Each plate 10 comprises at least one boss disposed at one end of the plate 10 and a bowl occupying most of the height of the plate 10.

Each plate 10 also has a peripheral edge 11 located in a vertical plane parallel to the contact plane P2. The peripheral edges 11 of two adjacent plates 10 are mutually joined sealingly to the first fluid, in particular by soldering, to delimit an internal volume between the two plates 10. The assembly of the peripheral edges 11 of two plates 10 is in the plane of symmetry P2 '.

The assembly by soldering of two plates 10 of the flat tube 3 makes it possible to define a circulation channel 7 of the first fluid in the heat exchanger 1. The circulation channel 7 is obtained by facing the cuvettes of each plate 10 constituting the flat tube 3. In addition, the brazing assembly of two plates 10 makes it possible to define an upper chamber 8 and a lower chamber 9 obtained by putting the bosses of each plate 10 opposite each other. constituting the flat tube 3. Each upper chamber 8 and each lower chamber 9 respectively comprise at least one communication port 4 allowing the communication of two upper chambers 8 adjacent to each other to define an upper collector and the communication of two adjacent lower chambers 9 between they define a lower collector.

The circulation channel 7, the upper chamber 8 and the lower chamber 9 form the internal volume between the two plates 10 defined during the assembly of two plates 10 of the flat tube 3 along their respective peripheral edges 11.

The communication orifice 4 of a plate 10 cooperates with the communication orifice 4 of an adjacent plate 10 to communicate two upper chambers 8, respectively two lower chambers 9, adjacent. The two plates 10 of the same pair are assembled together so that their concavities, defined by the bowl and the respective bosses, are facing each other.

The upper chambers 8 and the lower chambers 9 therefore cooperate respectively between them to define the two fluid collectors. The heat exchanger 1 comprises the upper collector and the lower collector respectively connected by the circulation channel 7 of each flat tube 3.

According to an alternative embodiment not shown, depending on the arrangement of the plates 10 forming the flat tubes 3, the heat exchanger 1 comprises two juxtaposed collectors arranged at one end of the flat tubes 3 and connected by the circulation channel 7 of each flat tube 3.

Likewise, in order to create a particular circulation of the first fluid in the heat exchanger 1, certain communication orifices 4 can be closed.

Thus, the arrangement of the flat tubes 3 makes it possible to carry out various types of circulation of the first fluid passing through the heat exchanger 1, in particular so-called "U" or "U" circulations.

The bosses of two adjacent plates 10 belonging to two different pairs of plates 10 are such as to create an interval in which the spacer 6 is arranged in the form of a corrugated metal sheet and to form a circulation passage. for a second fluid, atmospheric air according to the embodiment described. The vertices of the corrugations of the spacer 6 alternately come into contact with the two plates 10 limiting the passage housing the spacer 6.

According to a particular embodiment, each of the plates 10 further comprises a median partition capable of being assembled with a median partition homologous to the other plate 10 of the same pair. Thus, each of the internal volumes defined between two plates 10 of the same pair delimits a U-shaped path for the first fluid. The heat exchanger 1 further comprises an inlet pipe and an outlet pipe, not shown, respectively for the admission of the first fluid into the heat exchanger 1 and for the ejection of the first fluid out of the Heat exchanger 1. Thus, the first fluid can flow in the different chambers respectively formed by the pairs of plates 10.

In FIG. 3, each flat tube 3 is formed from the assembly, in particular by brazing, of two plates 10. Each plate 10 is obtained from the stamping of a metal strip. Each plate 10 has a peripheral edge 11 which is joined to another peripheral edge 11 of another plate 10, in particular by brazing.

The air flow 2 passing through the heat exchanger 1 is loaded with particles, especially water and / or dust, tending to interfere between two flat tubes 3 and to accumulate on the connecting edge 5 between two flat tubes 3. To avoid corrosion of the connecting edge 5, the present invention proposes specific arrangements of the connecting edge 5.

These specific arrangements are detailed in FIGS. 4 to 8 which are schematic illustrations of respective embodiments of contact zones 13 that each plate 10 comprises.

The specific arrangements according to the present invention have the common advantage of limiting access by the air stream 2 to a brazing joint 12 formed between the respective connecting edges 5 of two adjacent plates 10 of two flat tubes 3 in contact. For this purpose, each connecting edge 5 of the plate 10 has a contact area 13.30. Thus, the solder joint 12 constitutes a mechanical connection between two respective contact areas 13, commonly called collars, which comprise two plates 10 of two tubes. 3 adjacent dishes.

According to a variant of the present invention, the contact zone 13 of each plate 10 extends in the first direction xx beyond the second general plane of extension P2 or contact plane P2 of the plate 10. Thus, when the assembly of two plates 10 adjacent to each other, the respective contact areas 13 of the plates 10 are superimposed on an overlapping zone 14, so that the two second planes of general extension P2 or P2 contact planes of the two plates 10 be confused.

The overlap area 14 defines the solder joint 12 between two adjacent plates. Thus, the brazing joint 12 is protected by the contact zone 13 of one of the plates 10 of the air flow 2, the plates 10 advantageously constituting a barrier against a passage through the air flow 2 .

The overlap zone 14 extends over a length Lo defining the length of the solder joint 12. Preferably, the length Lo of the brazing joint 12 is advantageously greater than 1.5 mm, in particular greater than 2 mm. Such a length Lo contributes to ensuring a seal of the internal volume vis-à-vis the second flow. In addition, this length is optimized to ensure good resistance to corrosion.

The contact zones 13 are advantageously obtained during the stamping operation of the plates 10 so that the arrangements proposed by the present invention do not require any particular action to conform the connection edge 5 of the flat tubes 3 and the contact areas 13 of the plates 10.

According to a first embodiment as illustrated in FIG. 4, the contact zones 13 are of substantially cylindrical shape. More particularly, the contact zones 13 are arranged in a cylinder of axis D arranged perpendicularly to the second general plane of extension P2 or contact plane P2 of the plate 10 and the plane of symmetry P2 'of the flat tubes 3. The cylinder of axis D rests on the contour of the communication orifice 4 made in the connecting edge 5 of the flat tube 3. According to the example of FIG. 4, the contact zones 13 have an axial contact of length Lo according to FIG. axis D between them.

Figure 5 shows a second embodiment of the present invention wherein the contact areas 13 are substantially conical in shape. More particularly, the contact zones 13 are arranged in a cone of axis D 'arranged perpendicularly to the second general plane of extension P2 or contact plane P2 of the plate 10 and to the plane of symmetry P2' of the flat tubes 3. axis cone D 'rests on the contour of the communication orifice 4 made in the connecting edge 5 of the flat tube 3. According to the example of FIG. 5, the contact zones 13 have an axial contact of length Lo along the D axis between them.

These arrangements facilitate an assembly by interlocking two adjacent flat tubes 3.

It finally results from the arrangements shown in Figures 4 and 5, an ease of assembly of the flat tubes 3 with each other from a recess of their respective contact areas 13. Indeed, according to the first and second embodiments according to Figures 4 and 5, the contact areas 13 are generally rectilinear extension.

Figures 6 to 8 respectively show third, fourth and fifth embodiments of the present invention. According to these variants, the contact zones 13 comprise at least one inflection point 17. By inflection point is meant a part of the contact zone 13 at which the direction of extension of the contact zone 13 is modified.

According to this arrangement, the contact zone 13 then comprises a first elementary contact zone 15 and a second elementary contact zone 16 disposed on either side of the point of inflection 17. The presence of the inflection point 17 allows, in particular, to reduce the phenomenon of corrosion. Indeed, the point of inflection 17 contributes to limiting the development of corrosion in the contact surface 13 by constituting an obstacle to the propagation of the latter.

According to the variant illustrated in Figure 6 having a third embodiment, the contact areas 13 have a single point of inflection 17. Thus, according to a preferred example of the third embodiment, the contact areas 13 are bent. The first elemental contact area 15 and the second elementary contact area 16 are generally arranged orthogonally with each other. According to another embodiment, the first elementary contact zone 15 and the second elementary contact zone 16 form between them an angle A of between 0 ° and 180 °, preferably between 0 ° and 90 °.

The fourth variant illustrated in FIG. 7 is such that the contact zones 13 have two points of inflection 17. Thus, according to a preferred example of the fourth embodiment, the contact zones 13 are arranged in a baffle. According to this arrangement, the first elementary contact zone 15 and the second elementary contact zone 16 are generally arranged parallel to each other and are interconnected by a complementary contact zone 18 defined between the two points of inflection. 17.

According to a first alternative presented in FIG. 7, the first elementary contact zone 15 and the second elementary contact zone 16 extend in planes parallel to the second general extension plane P2 or P2 contact plane of the plate 10 and at the plane of symmetry P2 'of the flat tubes 3.

According to a second alternative not shown, the first elementary contact zone 15 and the second elementary contact zone 16 extend in planes perpendicular to the second general extension plane P2 or contact plane P2 of the plate 10 and to the plane of contact. symmetry P2 'of the flat tubes 3.

Finally, according to another alternative, the first elementary contact zone 15 and the second elementary contact zone 16 extend in planes forming any angle with the second general extension plane P2 or P2 contact plane of the plate 10 and the plane of symmetry P2 'of the flat tubes 3.

The contact areas 13 of the fourth embodiment are shaped such that the overlap area 14 is S-shaped.

According to a fifth variant illustrated in FIG. 8, the contact zones 13 have three or four points of inflection 17, so that the contact zones 13 form a hump or a peak. In the case where the contact zone 13 comprises three points of inflection 17, the point of inflection 17 between the two other points of inflection 17 is a cusp. In both cases, the contact zones 13 are formed generally parallel to the general plane of extension P2 or contact plane P2 of the plate 10 and to the plane of symmetry P2 'of the flat tubes 3. Preferably, the first elementary contact zone 15 and the second elementary contact zone 16 farthest from each other are parallel to each other.

According to the various embodiments described above, the contact zone 13 extends at least partially in the first direction xx from the second general extension plane P2 or P2 contact plane of the plate 10. Thus, according to the various modes As a result, the contact zone 13 extends completely along the first direction xx in the examples of FIGS. 4 and 5. The contact zone 13 extends partially along the first direction xx, the examples of FIGS. 6 to 8. Thus, in FIG. 6, the second elementary contact zone 16 of the contact zone 13 extends partially in the first direction xx. In FIG. 7, the complementary contact area 18 of the contact zone 13 extends partially in the first direction xx and in FIG. 8 the bump and / or the peak defined by the inflection points extend partially according to the first direction xx.

In the context of the present invention, the contact zone 13 may extend from the second general extension plane P2 or contact plane P2 of the plate 10 towards the interior of the upper chamber 8 and / or the lower chamber 9 and / or to the outside of the upper chamber 8 and / or the lower chamber 9.

The present invention has the advantage of allowing the use of common metal strips made of aluminum alloy and commonly referred to as long-life alloys. In particular, such alloys are alloys of the 3000 series covered by the soldering materials of the 4000 series. By using these alloys, the present invention allows a reduction of the thickness of the plates 10 to a thickness of less than 0.3 mm. more particularly equal to 0.25 mm, while maintaining an optimized resistance to corrosion.

Of course, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms and other variants that may be considered by those skilled in the art within the scope of the present invention and in particular any combination of the various embodiments described above.

Claims (12)

Claims1.- Plate (10) of a flat tube (3) for a heat exchanger (1) comprising at least one connecting edge (5) extending along a contact plane (P2) and comprising at least one zone contact point (13), characterized in that the contact zone (13) extends from the contact plane (P2) of the plate (10) at least in a first direction (xx) perpendicular to the contact plane (P2 ). 2. Plate (10) according to claim 1, characterized in that the contact zone (13) extends from the contact plane (P2) of the plate (10) in the first direction (xx) over a length greater than or equal to 1.5 mm. 3. Plate (10) according to claim 1 or 2, characterized in that the contact zone (13) comprises at least one point of inflection (17). 4. A plate (10) according to claim 3, characterized in that the contact zone (13) comprises a first elementary contact zone (15) and a second elementary contact zone (16) located on either side the inflection point (17). 5. Plate (10) according to claim 4, characterized in that the first elementary contact area (15) and the second elementary contact area (16) are parallel to each other. 6. Plate (10) according to claim 4, characterized in that the first elementary contact area (15) and the second elementary contact area (16) are perpendicular to each other. 30 7. A plate (10) according to claim 4, characterized in that the first elementary contact zone (15) and the second elemental contact zone (16) form between them an angle (A) between 0 ° and 180 ° , preferably enter 0 ° and 90 °. 8. Plate (10) according to one of claims 1 to 7, characterized in that the 5 contact zone (13) is shaped into a baffle. 9. A plate (10) according to one of claims 1 to 8, characterized in that the contact zone (13) extends in at least a second direction (y-y) parallel to the contact plane (P2). 10.- Flat tube (3) consisting of two plates (10) according to any one of the preceding claims. 11. Heat exchanger (1) having at least two flat tubes (3) according to claim 10. 12- heat exchanger (1) according to claim 11, characterized in that the flat tubes (3) are assembled by their contact areas (3) by a solder joint (12) of greater than or equal to 1.5 mm. 10 20