FR3037643A1 - HEAT EXCHANGER AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Abstract

The present invention relates to a heat exchanger (1) comprising: ○ a bundle (2) of tubes comprising a multiplicity of tubes (20) arranged parallel to each other and spacers (21) arranged between said tubes (20), ○ a collector plate (4) comprising holes (43) respectively bordered by first collars (44) in which ends (22) of the tubes (20) are introduced, the tube bundle (2) being brazed and the collector plate (4) ) having at least one compressible seal (41) forming second collars (45), the second collars (45) being compressed between the first collars (43) and the ends (22) of the tubes (20) to provide sealing between said ends (22) of the tubes (20) and the corresponding first flanges (43).

Description

1 Heat exchanger and method of manufacturing the same. The invention relates to a heat exchanger, in particular for a motor vehicle, and to its method of manufacture. It relates more particularly to a heat exchanger of the type comprising a multiplicity of tubes between which are inserted tabs. The tubes are generally tubes of oval or oblong section, defined by a major axis and a minor axis, and having ends inserted into holes in a header plate. To ensure a good seal and facilitate manufacture, the tubes, spacers and the collector plate are generally made of metal material and fixed together during a single soldering step. However, when using the heat exchanger, the connection between the tubes and the collector plate is rigid and can not compensate for the expansion and retraction phenomena related to the temperature variation. Over time these bonds weaken and breaks or leaks can occur. It is therefore an object of the present invention to at least partially overcome the disadvantages of the prior art and to provide an improved heat exchanger and its manufacturing method. The present invention therefore relates to a heat exchanger comprising: a tube bundle comprising a multiplicity of tubes arranged parallel to each other and spacers arranged between said tubes, a collector plate comprising holes respectively bordered by first collars in which ends of the tubes are introduced, the bundle of tubes being brazed and the collecting plate comprising at least one compressible seal forming second collars, the second collars being compressed between the first collars and the ends of the tubes to ensure the sealing between said ends of the tubes and the corresponding first collars.

The use of a compressible gasket or a multitude of compressible seals to make the connection between the beam and the collector plate, allows a certain flexibility that can absorb the expansions and retractions related to temperature variations . The connection between the beam and the collector plate is therefore more resistant to these temperature variations. There is a synergistic effect between the flexibility of the connection between the beam and the plate collector plate, with the fact that the beam is brazed. As a result, the heat exchanger benefits from optimal thermal performance, linked to the brazed beam, and better resistance to thermal variation, linked to the connection between the beam and the plate collector plate. In addition, because the collector plate is not brazed, said collector plate may be of a smaller thickness and it is less necessary to strengthen the collector. According to one aspect of the invention, at least the end of each tube has an oblong section.

According to another aspect of the invention, the ends of the tubes comprise a first flare and a bearing zone compressing the compressible seal. According to another aspect of the invention, the ends of the tubes comprise at least one second flare overlying the compressible seal.

According to another aspect of the invention, the second flare is made on a limited portion of the ends of the tubes.

According to another aspect of the invention, the compression ratio of said second collars is between 10% and 50% and preferably between 25% and 35%. The invention also relates to a method of manufacturing a heat exchanger as described above and comprising the following steps: a) assembling a bundle of tubes comprising a plurality of tubes arranged parallel to each other and spacers arranged between said tubes, b) brazing the tubes with the spacers, c) assembling a collector plate provided with holes lined with first collars of section corresponding to the ends of the tubes and equipped with a compressible seal forming second clean collars to be respectively engaged through the holes, d) insertion of the ends of the tubes into the holes of the header plate so as to compress the second collars of the compressible seal. According to one aspect of the method according to the invention, the step d) of inserting the ends of the tubes into the holes of the collector plate so as to compress the second collars comprises a first substep of insertion of the ends of the tubes. in the holes of the collector plate and a second substep of producing a first flare and a bearing zone at the ends of the tubes. According to another aspect of the method according to the invention, the step d) of inserting the ends of the tubes into the holes of the collector plate so as to compress the second collars is a step of inserting the ends of the tubes into force. in the holes of the header plate, at least said ends having a size greater than the size of the openings of the second collars.

According to another aspect of the method according to the invention, the method comprises an additional step of producing at least a second flaring of the ends of the tubes surmounting the compressible seal.

According to another aspect of the method according to the invention, the second flare is made on a limited portion of the ends of the tubes. Other characteristics and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawings in which: FIG. 1 shows a schematic representation in perspective of FIG. 2 shows a diagrammatic representation in perspective and in section of a heat exchanger, FIG. 3 shows a diagrammatic sectional and exploded representation of a collector plate, FIG. 3 'shows a representation of a heat exchanger, FIG. schematic sectional view of the collector plate of Figure 3, Figure 4 shows a schematic representation of the collector plate of Figure 3 according to the plane of blow XX, Figure 5 shows a schematic sectional representation of a heat exchanger according to a first embodiment, FIGS. 6 to 8 show a schematic representation in section of a heat exchanger according to a second embodiment in the course of 25 different stages of manufacture. The identical elements in the different figures bear the same references.

The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined to provide other embodiments. In the present description, it is possible to index certain elements or parameters, such as for example first element or second element as well as first parameter 10 and second parameter, or first criterion and second criterion, and so on. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria close but not identical. This indexing does not imply a priority of one element, parameter or criterion with respect to another, and it is easy to interchange such denominations without departing from the scope of the present description.

This indexation does not imply either an order in time for example to appreciate such or such criteria. The heat exchanger 1 shown in FIGS. 1 and 2 comprises a bundle 2 formed of a multiplicity of tubes 20 within which a first heat transfer fluid 20 can circulate. The tubes 20 are arranged parallel to each other and superposed. Between the tubes 20, there are spacers 21 which act as a disrupter and increase the heat exchange surface with a second heat transfer fluid passing between said tubes 20. The tubes 20 and the spacers 21 are made of metal materials and are brazed between The fact of having a brazed beam 2 makes it possible to improve the thermal performance, that is to say the heat exchange between the two heat transfer fluids, with respect to a mechanically assembled beam. As shown in Figures 1 and 2, the tubes 20 preferably have an oblong and relatively flat shape. In addition, the tubes 20 may have a spacer 26 therebetween between their internal walls. This spacer 26 allows good rigidity of said tubes 20. The heat exchanger 1 also comprises two manifolds or water boxes 5 disposed at each end 22 of the tubes 20. These manifolds comprise a header plate 4 and a cover (not shown) from covering said collector plate 4 and close the collector. These collectors allow the collection and / or distribution of the first heat transfer fluid so that it circulates in the tubes 20.

As shown in more detail in FIG. 3 ', the header plate 4 is sealingly connected between the collector and the brazed beam 2. Said collector plate 4 comprises a core 40, which may be of generally rectangular shape, delimiting a multiplicity of holes 43, of section corresponding to the shape of the section of the tubes 20 and adapted to receive the ends 22 of the tubes. Each hole 43 is bordered by a first collar 44 directed towards the inside of the bundle 2. The holes 43 are of a size similar to the openings of the first collars 44. The first collars 44 may advantageously be integral with the collector plate 4 and be for example formed at the same time as the holes 43 by stamping.

As the holes 43 and the first flanges 44 have a shape corresponding to that of the section of the tubes 20, or at least their ends 22, and that this shape is generally oblong, it is possible to characterize said holes 43 and first collars 44 along two axes of different lengths. The length L1 corresponds to the largest length and may correspond to the width of the hole 43 as illustrated in FIGS. 3, 3 'and 5 to 8. The length 11 corresponds to the smallest length and may correspond to the thickness of the hole 43 as illustrated in FIG. 4. To allow insertion of the ends 22 of the tubes 20 within the first collars 44, the lengths L 1 and 11 of the hole 43 are greater than those of the ends 22 of the tubes 20.

This is the width and thickness of the holes 43 echoing with the width and the thickness of the tubes 20 which are intended to be introduced into said holes 43. The core 40 is extended by a peripheral groove 42 ending by a peripheral rim 46 forming foldable legs. The peripheral groove 42 is intended to receive the rims of the cover and the peripheral rim 46 can be folded down to fix said cover on the header plate 4. The header plate 4 receives at least one compressible seal 41 to allow in particular sealing at level of the holes 43.

According to a first embodiment, illustrated in FIGS. 1 and 2, the manifold plate 4 may comprise only one compressible seal 41. This compressible seal 41 comprises a core that is applied to the This core 40 of the collapsible seal 41 is connected to a multiplicity of second collars 45 which are each introduced into a hole 43. At the assembly of the bundle 2 with the collector plate 4 , the second collars 45 are compressed between the first collars 43 and the ends 22 to seal between said ends 22 of the tubes 20 and the corresponding first flanges 43. The compression ratio of the flanges 45 is 30%. According to variants of the invention, the level is between 10% and 50% and preferably between 25% and 35%. Furthermore, the core of the compressible seal 41 may form at its periphery a bead 47 disposed in the peripheral groove 42 and adapted to seal with the lid when the peripheral flange 46 is folded.

According to a second embodiment not shown, the manifold plate 4 may comprise a plurality of compressible seals 41 which form flanges 45 which each enter a hole 43 to seal between the end 22 a tube 20 and the first collar 43 corresponding. In this embodiment the sealing with the lid can be achieved by an independent compressible seal and placed in the peripheral groove 42. The use of a compressible seal 41 or a multitude of Sealing seals 41 to provide the connection between the bundle 2 and the collector plate 4, allows a certain flexibility which can absorb the expansions and shrinkages related to temperature variations. The connection between the beam 2 and the collector plate 4 is therefore more resistant to these temperature variations. There is a synergistic effect between the flexibility of the connection between the beam 2 and the collector plate 4, 10 with the fact that the beam 2 is brazed. As a result, the heat exchanger 1 benefits from optimal thermal performance, linked to the brazed beam 2, and better resistance to thermal variations, linked to the connection between the beam 2 and the collecting plate 4. Moreover, because of the that the collector plate 4 is not brazed, said collector plate 4 may be of a smaller thickness and it is less necessary to strengthen the collector. The second collars 45 also have a shape corresponding to that of the section of the tubes 20, or at least their ends 22. It is therefore also possible to characterize said second collars 45 along two axes of different lengths. The length L2 corresponds to the width of the opening of the second collar 45 when the compressible seal 41 is not compressed, as shown in FIGS. 3, 3 ', 4 and 6. The length 12 corresponds to the thickness of the opening of the second collar 45 when the compressible seal 41 is not compressed, as shown in FIG. 4. In the compressed state, the opening of the second collar 45 to 25 at least one of these lengths (width and / or thickness) which increases, for example as shown in Figures 5, 7 and 8 where the width of the opening of the compressible seal 45 is larger and corresponds to a length L2 '. As above, this is the width and thickness of the openings of the second flanges 45 echoing with the width and thickness of the tubes 20 which are intended to be introduced into said openings of the second flanges 45. The ends 22 of the tubes 20 have a size greater than that of the openings 5 of the second collars 45 but less than that of the holes 43 in order to compress the compressible seal 41 at the level of the second collars 45. By larger or smaller size, it is understood that at least the width and / or the thickness differ between the tubes 20 and the holes 43 or the openings of the second collars 45. As shown in FIG. 5, the body of a tube 20 and its end 22 may have a width and a thickness identical, that is to say that the size (width and thickness) of the tube 20 is constant within the beam 2. The compressible seal 41 is compressed because the width and thickness of the tube 20 as a whole is greater than that of the openings of the second collars 45 and less than that of the holes 43.

Conversely, and as shown in FIGS. 7 and 8, the body of a tube 20 and its end 22 may have a width and / or a thickness that differs. The end 22 may have a sealing flange 23 which will be named in the following first flare 23 on the inside of the beam 2 and which increases the width and / or the thickness of said end 22. The end 22 comprises also a bearing zone 24 which is wider and / or thicker than the rest of the body of the tube 20 because of the first flaring 23 and which compresses the compressible seal 41. The ends 22 of the tubes 20 may also comprise at least one second flare 25 - which is a retaining flare for mechanical locking - on the outer side of the beam 2 and which overcomes the compressible seal 41 as illustrated in Figures 1, 2 and 8. This second flare 25 may in particular be made on a limited portion of the ends 22 of the tubes 20. This second flaring 25 allows in particular the locking and holding in place of the header plate 4 on the beam 2 In the example shown in FIGS. 1 and 2, the ends 22 of the tubes 20 each comprise two second flares 25 made on a limited portion. The first 23 and second 25 flares of the ends 22 are located on either side of the collector plate 4.

The present invention also relates to a method of manufacturing a heat exchanger 1 as described above and comprising the following steps: a) assembly of a bundle 2 of tubes comprising a multiplicity of tubes 20 arranged parallel to each other and spacers 21 arranged between said tubes 20, b) brazing tubes 20 with tabs 21, c) assembling a header plate 4 provided with holes 43 forming first collars 44 of section corresponding to the ends 22 of the tubes 20 and equipped with a compressible seal 41 forming second flanges 45 adapted to be engaged respectively through the holes 43, d) insertion of the ends 22 of the tubes 20 into the holes 43 of the header plate 4 so as to compress the second collars 45 of the compressible seal 41.

According to one embodiment, and especially when the size of the end 22 of the tubes 20 is less than or equal to the size of the opening of the second collar 45, this last step d) may comprise a first substep of insertion of the ends 22 of the tubes 20 in the holes 43 of the header plate 4 and a second substep of producing a first flare 23 and the bearing zone 24 at the ends 22 of the tubes 20. This first sub-step is illustrated in Figure 6 and the insertion is thus easy to achieve because the end 22 of the tube 20 has a size less than or equal to the opening of the second collar 45 and the compression of the compressible seal 41 is formed by the formation of the first flaring 23 and the bearing zone 24, as illustrated in FIGS. 7 and 8. This first flaring 23 and the support zone 24 may, for example, be made with the aid of FIG. a correspo shaped punch In another embodiment, the step d) of inserting the ends 22 of the tubes 20 into the holes 43 of the header plate 4 so as to compress the second collars 45 of the seal. compressible seal 41 may be a step of inserting the ends 22 of the tubes 20 into the holes 43 of the collecting plate 4 in such a way that the compressible seal 41 is compressed, at least the ends 22 of the tubes 20 have a size greater than that of the openings of the second flanges 45, whether it is by a larger size in general of the assembly of the tube 20, as illustrated in FIG. 6, or else by the fact of a first flaring 23 and of a bearing zone 24, as illustrated in FIGS. 7 and 8, made beforehand on the ends 22 of the tubes 20. The manufacturing method may also comprise an additional step 15 of producing at least one second flare 25 which overcomes the compressible seal 41 as illustrated in FIGS. 1, 2 and 8. This second flaring 25 can be made on a limited portion of the ends 22 of the tubes 20. Thus, it can clearly be seen that the heat exchanger 1 according to FIG. the invention, benefits from optimal thermal performance, linked to the brazed beam 2, and better resistance to thermal variations, linked to the mechanical connection between the beam 2 and the collector plate 4.

Claims (11)

REVENDICATIONS1. Heat exchanger (1) comprising: o a bundle (2) of tubes comprising a plurality of tubes (20) arranged parallel to each other and spacers (21) arranged between said tubes (20), o a collector plate (4) ) comprising holes (43) respectively bordered by first flanges (44) into which are introduced ends (22) of the tubes (20), characterized in that the bundle (2) of tubes is brazed and that the collector plate (4) ) has at least one compressible seal (41) forming second collars (45), the second collars (45) being compressed between the first collars (43) and the ends (22) of the tubes (20) to provide the sealing between said ends (22) of the tubes (20) and the corresponding first flanges (43). 2. Heat exchanger (1) according to claim 1, characterized in that at least the end (22) of each tube (20) has an oblong section. 3. heat exchanger (1) according to one of the preceding claims, characterized in that the ends (22) of the tubes (20) comprise a first flare (23) and a bearing zone (24) compressing the gasket compressible seal (41). 4. Heat exchanger (1) according to one of the preceding claims, characterized in that the ends (22) of the tubes (20) comprise at least a second flare (25) overlying the compressible seal (41). 3037643 13 5. heat exchanger (1) according to the preceding claim, characterized in that the second flaring (25) is formed on a limited portion of the ends (22) of the tubes (20). 5 6. Heat exchanger (1) according to any one of the preceding claims, characterized in that the compression ratio of said second collars is between 10% and 50% and preferably between 25% and 35%. 7. A method of manufacturing a heat exchanger (1) according to one of claims 1 to 6, characterized in that it comprises the following steps: a) assembly of a bundle (2) of tubes comprising a multiplicity of tubes (20) arranged parallel to each other and spacers (21) arranged between said tubes (20), b) brazing of the tubes (20) with the spacers (21), 15 c) assembly of a collector plate (4) provided with holes (43) flanked by first flanges (44) of section corresponding to the ends (22) of the tubes (20) and equipped with a compressible seal (41) forming clean second flanges (45) to be respectively engaged through the holes (43), d) insertion of the ends (22) of the tubes (20) into the holes (43) of the header plate (4) so as to compress the second collars (45) of the compressible seal (41). 8. A method according to claim 7, characterized in that the step d) of inserting the ends (22) of the tubes (20) in the holes (43) of the collector plate (4) so as to compress the second flanges (45) comprises a first substep of insertion of the ends (22) of the tubes (20) in the holes (43) of the collector plate (4) and a second substep of making a first flare ( 23) and a support zone (24) at the ends (22) of the tubes (20). 3037643 14 9. The method of claim 7, characterized in that the step d) insertion of the ends (22) of the tubes (20) in the holes (43) of the header plate (4) so as to compress the second collars (45) is a step of forcibly inserting the ends (22) of the tubes (20) into the holes (43) of the header plate (4), at least said ends (22) having a size larger than the size openings of the second collars (45). 10. Method according to one of claims 7 to 9, characterized in that it comprises an additional step of producing at least a second flare (25) of the ends (22) of the tubes (20) overlying the gasket. compressible seal (41). 11. Method according to the preceding claim, characterized in that the second flare (25) is formed on a limited portion of the ends (22) of the tubes 15 (20).