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1. WO2020115043 - CONSTITUENT HEADER OF A HEAT EXCHANGER

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

CONSTITUENT HEADER OF A HEAT EXCHANGER

The present invention relates to a constituent header of a heat exchanger. The subject thereof is such a header and a heat exchanger comprising such a header.

A motor vehicle is commonly equipped with a refrigerant circuit for modifying a temperature of the air inside a passenger compartment of the motor vehicle. The refrigerant circuit comprises at least one heat exchanger, such as a condenser, a gas cooler or an evaporator, which is designed to allow heat energy to be transferred between the refrigerant flowing inside the heat exchanger and an air flow passing through the latter.

The heat exchanger comprises a plurality of tubes that are provided for the air flow to pass through and are interposed between two headers, for example an inlet header for the inlet of refrigerant into the heat exchanger and an outlet header for letting the refrigerant out of the heat exchanger, according to one exemplary embodiment of such a heat exchanger.

It is known practice to produce heat exchangers that exhibit several circulation passes for the refrigerant passing through the heat exchanger and, to this end, to subdivide the headers of the heat exchanger with partitions that separate the passes from one another. Reference could be made for example to the document WO2015/071069, which describes a header of the abovementioned type.

Such heat exchangers are commonly produced by brazing the partitions, headers and tubes during the assembly of the constituent elements of the heat exchanger. Such a brazing operation requires precise positioning of these elements and more particularly of the partitions within the headers, in order to avoid external leaks of the refrigerant out of the heat exchanger or internal leaks of refrigerant between two adjacent passes.

Therefore, a technical problem to be solved lies in the need to have a header designed to avoid such leaks, in particular on the basis of precise positioning of the partitions, and more particularly positioning of the partitions within respective planes that are perpendicular to a longitudinal direction of extension of the header accommodating said partitions.

An aim of the present invention is to provide a header designed to prevent any leaks of refrigerant, external or internal, in particular on the basis of optimized positioning of the partitions accommodated within the headers of the heat exchanger.

A header of the present invention is a constituent header of a heat exchanger.

The header comprises at least one header plate and a cover that jointly delimit an internal space. The header also comprises at least one partition that subdivides the internal space into two sections. The header has an internal face bordering the internal space and an external face oriented towards the outside of the header. The internal face comprises at least one housing for receiving the partition.

According to the present invention, the internal face has at least one cavity and one protrusion, the protrusion being interposed between the cavity and the housing for receiving the partition.

The header advantageously comprises any one of at least the following features, on their own or in combination:

- the housing for receiving the partition is more particularly intended to receive a peripheral edge face of the partition. This housing may for example be in the form of a slot,

- the protrusion constitutes a bulge emerging from the internal face, which prevents the partition from escaping from the housing provided for receiving it. The protrusion thus forms a means that prevents the partition from pivoting about itself, such that the partition ensures leaktightness between the two sections of the internal space delimited by the partition. Therefore, the partition is immobilized by the protrusion inside the housing, including when a clearance is formed between the housing for receiving the partition and the partition itself, in order to make it easier to fit the latter in the housing,

- since the cover comprises a cover base and two cover flanks on either side of the cover base, the housing, cavity and the protrusion can for example be formed in one cover flank or in both cover flanks, the cover base otherwise being free of this housing for receiving the partition,

- since the header plate comprises a plate base and two plate flanks on either side of the plate base, the housing, the cavity and the protrusion can for example be formed in one plate flank or in both plate flanks, the plate base otherwise being free of this housing for receiving the partition,

- the protrusion is integral with the internal face of the header. It is understood that the protrusion is formed by a deformation of the internal face of the header and that there is continuity of material between the header and the protrusion, which together form a one-piece element and are only separable from one another by destroying one and/or the other. It is also understood that the header is made of a material, preferably a metal material, of which the ductility allows the internal face of the header to be deformed to form the protrusion when the cavity is produced,

- a volume of the cavity is in particular greater than or equal to a volume of the protrusion,

- when the protrusion is created by the formation of the cavity in the internal face at least, it is understood that the protrusion is formed by displacement of material previously situated at the location of the cavity, this material being displaced from the position of the cavity in order to form the protrusion. As a result, the protrusion forms an obstacle to pivoting of the partition inside the housing provided for receiving it,

- the cavity and the protrusion are local deformations of the internal face of the header. This is understood as meaning that the cavity and the protrusion are located at one point on the internal face, the cavity being produced for example by insertion of a punch having a tapered end into the internal face of the header. The local character does not prevent there from being several cavity and protrusion pairings. On the other hand, the cavity is a localized form of substantially identical length and width,

- the cavity and the protrusion are lateral deformations of the internal face of the header. This is understood as meaning that the cavity and the protrusion extend laterally in the thickness of the header within planes that intersect the internal face and the external face of the header. The cavity is produced for example by insertion of a punch having an end designed as an edge face extended in the form of a circular arc,

- a depth of the cavity measured between the internal face of the header and a cavity bottom is less than a thickness of the header measured between the internal face and the external face of the header. These provisions are such that the cavity does not open out towards the outside of the header, thereby ensuring that the header is leaktight. In other words, the external face of the header is free of any deformation in line with the cavity,

- the cavity opens out through the external face. These provisions are such that the cavity forms a passage between the internal space and the exterior of the header, this passage being closed off during an operation of brazing the heat exchanger that is carried out after a step of forming the cavity through the header. The cavity is closed off in particular by one of the flanks of the cover when the cavity is formed through one of the flanks of the header plate, or the cavity is closed off by one of the flanks of the header plate when the cavity is formed through one of the flanks of the cover,

- the protrusion forms a means for holding the partition in position on a partition plane that is orthogonal to a longitudinal direction of extension of the header,

- the cover comprises at least one cover base bordered by two cover flanks, at least one of the cover flanks being ended by a cover edge face, and the cavity is formed at least in a manner straddling the cover edge face. These provisions make it possible to keep the partition as far as possible from the cover base, thereby limiting the risk of the partition turning in the header plate,

- the header plate comprises at least one plate base bordered by two plate flanks, at least one of the plate flanks being ended by a plate edge face, and the cavity is formed at least in a manner straddling the plate edge face. These provisions make it possible to keep the partition as far as possible from the plate base, thereby limiting the risk of the partition turning in the cover,

- the cavity is formed along a deformation axis orthogonal to the longitudinal direction of extension of the header,

- a distance measured between a proximal edge of the housing of the partition and the deformation axis is equal to the thickness of the cover +/- io%. These

provisions are such that the cavity is produced at such a proximity to the housing that it allows the protrusion resulting from the cavity to border the housing,

- the internal face has at least one cavity and protrusion pairing, or even a plurality of cavity and protrusion pairings,

- at least two cavity and protrusion pairings are distributed on either side of the partition, being formed on one and the same flank, which is either a cover flank or a plate flank. In such a case, a first cavity and protrusion pairing is formed on a flank on a first side of the partition, while a second cavity and protrusion pairing is formed on this same flank, but on the other side of the partition,

- at least two cavity and protrusion pairings are diametrically opposed with respect to the longitudinal direction of extension of the header. In such a case, a first cavity and protrusion pairing is formed on a first flank on a first side of the partition, while a second cavity and protrusion pairing is formed on a second flank opposite the first flank with respect to the internal volume, this second pairing being provided on the same side of the partition as the first pairing,

- at least two cavity and protrusion pairings, and advantageously four pairings, are formed symmetrically with respect to a centre of symmetry of the partition. In such a case, a first cavity and protrusion pairing is formed on a first flank on a first side of the partition, while a second cavity and protrusion pairing is formed on a second flank opposite the first flank with respect to the internal volume, this second pairing being provided on the other side of the partition from the first pairing,

- the internal face has at least four cavities and four protrusions, which are distributed at the corners of a quadrilateral accommodating the partition.

A further subject of the present invention is a heat exchanger comprising at least one such header.

A further subject of the present invention is a refrigerant circuit comprising at least one such heat exchanger.

A further subject of the present invention is a method for assembling such a header, which successively comprises at least the following steps:

- a first step of providing the housing in the internal face of the header,

- a second step of fitting the partition inside the housing provided for receiving it,

- a third step of providing the cavity and the protrusion on the inside of the internal face of the header.

Advantageously, the assembly method may comprise a fourth step of securing the cover and the header plate, the partition being interposed between the cover and the header plate.

Further features, details and advantages of the invention will become more clearly apparent from reading the following description given by way of indication with reference to the drawings, in which:

- Figure l is a frontal view of a heat exchanger of the present invention,

- Figure 2 is a partial view of a lateral section of the heat exchanger illustrated in Figure l,

- Figures 3 to 6 are views of exemplary embodiments of the heat exchanger illustrated in Figure 2.

It should first of all be noted that while the figures explain the invention in detail for the implementation of the invention, said figures may of course serve the better to define the invention as appropriate.

In the figures, the terms longitudinal, transverse, lateral, vertical refer to the orientation, in an orthonormal frame of reference Oxyz, of a heat exchanger l illustrated in Figure l. In this frame of reference, the axis Ox represents the longitudinal direction, the axis Oy represents the lateral direction, and the axis Oz represents the transverse direction. In this frame of reference, a longitudinal plane is parallel to the plane Oxz, a lateral plane is parallel to the plane Oyz and a transverse plane is parallel to a plane Oxy.

In Figure l, the heat exchanger l of the present invention extends as a whole within a first plane Pi, which is parallel to the transverse plane Oxy. The heat exchanger l comprises a plurality of tubes 2, which are mutually parallel and parallel to the lateral direction Oy. The tubes 2 are interposed between two headers 3, which are mutually parallel and extend along a first longitudinal axis of extension At, which is parallel to the axis Ox.

According to one exemplary embodiment, one of the headers 3 is equipped with an inlet 4 for a refrigerant 5, while the other of the headers 3 is equipped with an outlet 6 for the refrigerant 5. According to another exemplary embodiment, the same header 3 is able to be provided with the inlet 4 and the outlet 6 for the refrigerant 5.

The heat exchanger 1 is a constituent of a circuit in which the refrigerant 5 flows, the circuit being intended to equip a motor vehicle in order to modify a temperature of air contained in a passenger compartment of the motor vehicle. Depending on the position of the heat exchanger 1 within the refrigerant circuit, depending on the nature of the refrigerant 5, and depending on the manners in which the refrigerant circuit works, the heat exchanger 1 is either a condenser, a gas cooler, an evaporator, or even a radiator, and is able to exchange heat energy with an air flow 7. The air flow 7 passes through the heat exchanger 1, in particular by flowing between the tubes 2 in a direction parallel to the axis Oz. In order to make such a transfer of heat between the refrigerant 5 contained in the tubes 2 and the air flow 7 that flows between the tubes 2 easier, inserts 8, partially depicted, are for example disposed between two adjacent tubes 2.

The heat exchanger 1 is a heat exchanger having a plurality of circulation passes 9 for the refrigerant 5 passing through the heat exchanger 1. This is understood as meaning that the refrigerant 5 passes several times from one of the headers 3 to the other from its entry into the interior of the head exchanger 1 via the inlet 4 until its evacuation from the heat exchanger 1 via the outlet 6. In other words, the heat exchanger 1 is designed such that the refrigerant 5 passes back and forth several times between each of the headers 3.

To this end, each header 3 accommodates at least one partition 10, which is flat and extends on a partition plane P2 parallel to the plane Oyz. The partition 10 subdivides an internal space 11 delimited by the header 3 into two sections 11a, 11b situated on either side of the partition 10. In other words, the header 3 delimiting the internal space 11 accommodates at least one partition 10 that separates the internal space 11 into two sections 11a, 11b.

The header 3 has an internal face 12, which borders the internal space 11, and an external face 13, which is oriented towards the outside of the header 3.

In Figure 2, the header 3 comprises a cover 14 and a header plate 15, which, when assembled, delimit the internal space 11. The header plate 15 is designed to receive one end of each of the tubes 12 and to allow refrigerant 5 to flow from the header 3 to the tubes 2 and vice versa.

The cover 14 comprises a cover base 14a and two cover flanks 14b on either side of the cover base 14a. The cover 14 has an overall U-shaped design, the cover base 14a forming the bottom of the U and the cover flanks 14b forming the legs of the U.

The header plate 15 comprises a plate base 15a and two plate flanks 15b on either side of the plate base 15a. The header plate 15 likewise has an overall U-shaped design, the plate base 15a forming the bottom of the U and the plate flanks 15b forming the legs of the U.

According to one embodiment of the header 3, and as illustrated in Figure 2, the cover flanks 14b are inserted between the plate flanks 15b in close contact therewith in order to jointly delimit the internal space 11. According to another embodiment of the header 3, the plate flanks 15b are inserted between the cover flanks 14b in close contact therewith in order to jointly delimit the internal space 11.

In Figures 3 to 6, the internal face 12 of the header 3 comprises at least one housing 16 for receiving the partition 10. The housing 16 is for example designed as a slot formed within a plane parallel to the lateral plane Oyz. The housing 16 is intended to receive an edge face 17 of the partition 10. The edge face 17 of the partition 10 is the edge of the partition 10 that has the smallest dimension.

The internal face 12 of the header 3, which is a constituent part either of the cover 14 or of the header plate 15, has at least one cavity 18 and one protrusion 19. The protrusion 19 is interposed between the cavity 18 and the housing 16 for receiving the partition 10. It is understood that the protrusion 19 borders the housing 16 so as to immobilize the partition 10 inside the housing provided for receiving the partition 10.

Advantageously, the protrusion 19 is integral with the internal face 12 of the header 3. There is thus a continuity of material between the internal face 12 of the header 3 and the protrusion 19, which is obtained in particular by deformation of the internal surface 12 of the header 3 during the formation of the cavity 18, this formation of the cavity 18 bringing about the formation of the protrusion 19. In other words, the protrusion 19 is obtained simultaneously during the formation of the cavity by the deformation of the internal surface 12 of the header 3, whether the internal surface 12 is that of the cover 14, as shown in Figures 3 and 5, or the internal surface 12 is that of the header plate 15, as shown in Figures 4 and 6.

The cavity 18 and the protrusion 19 are respectively local deformations of the internal face 12 of the header 3. This is understood as meaning that the cavity 18 and the protrusion 19 extend over small areas of the internal face 12 and are for example obtained by punching of the internal surface 12, carried out in particular with the aid of a punch having a tapered end.

According to one embodiment variant, the cavity 18 and the protrusion 19 are lateral deformations of the internal face 12 of the header 3 and are for example obtained with a punch, one end of which extends within a lateral plane of the header

3

The cavity 18 is formed along a deformation axis A2 that is orthogonal to the direction of longitudinal extension At of the header 3.

According to the embodiments illustrated in Figures 3 and 4, a depth P of the cavity 18 measured between the internal face 12 of the header 3 and a cavity bottom 20 is less than a thickness E of the header 3 measured between the internal face 12 and the external face 13 of the header 3. In this case, the cavity 18 does not open out through the external face 13 of the header 3.

According to the embodiments illustrated in Figures 5 and 6, a depth P of the cavity 18 measured between the internal face 12 of the header 3 and a cavity bottom 20 is equal to a thickness E of the header 3 measured between the internal face 12 and the external face 13 of the header 3. In this case, the cavity 18 opens out through the internal face 12 and the external face 13 of the header 3. In other words, and before brazing, the cavity 18 can be a cutout in the cover 14 or in the header plate 15.

In Figures 3 and 5, with the cover 14 comprising at least one cover flank 14b ended by a cover edge face 14c, the cavity 18 is formed at least in a manner straddling the cover edge face 14c.

In Figures 4 and 6, with the header plate 15 comprising at least one plate flank 15b ended by a plate edge face 15c, the cavity 18 is formed at least in a manner straddling the plate edge face 15c.

A distance D measured between a proximal edge 21 of the housing 16 for receiving the partition 10 and the deformation axis A2 is equal to the thickness E of the header 3 +/- 10%. In other words, the cavity 18 is formed close to the housing 16 for receiving the partition 10, such that the protrusion 19 resulting from the formation of the cavity 18 borders, or impinges on, the housing 16, so as to immobilize the partition 10 inside the housing 16 in such a position that the partition 10 is disposed perpendicularly to the axis of longitudinal extension Ai of the header 3

In Figure 3, there are four cavities 18 and protrusions 19 and they are distributed symmetrically at the corners of a quadrilateral accommodating the partition 10. According to this configuration, the cavities 18 and the protrusions 19 are formed on the constituent internal face 12 of the cover 14.

In Figure 4, there are two cavities 18 and protrusions 19 and they are distributed symmetrically with respect to a centre of symmetry 22 of the partition 10. According to this configuration, the cavities 18 and the protrusions 19 are formed on the constituent internal face 12 of the cover 14. A first cavity and protrusion pairing is thus formed on one side of the partition 10, and a second cavity and protrusion pairing is formed on the other side of the partition 10.

In Figure 5, there are four cavities 18 and protrusions 19 and they are distributed symmetrically at the corners of a quadrilateral accommodating the partition 10. According to this configuration, the cavities 18 and the protrusions 19 are formed on the constituent internal face 12 of the header plate 15.

In Figure 6, there are two cavities 18 and protrusions 19 and they are distributed symmetrically with respect to a centre of symmetry 22 of the partition 10. According to this configuration, the cavities 18 and the protrusions 19 are formed on the constituent internal face 12 of the header plate 15.

The cavities 18 of the embodiments in Figures 5 and 6 are closed off by the

presence of the header plate 15, when they are formed in the cover 14. The same goes for when the cavities 18 are formed in the header plate 15 and closed off by the cover 14. In all cases, the cavity is configured to be filled and closed off by a layer of added material present on the cover or on the header plate, once the heat exchanger passes into the furnace.

A method for assembling such a header 3 successively comprises at least the following steps:

- a first step of providing the housing 16 in the internal face 12 of the header 3,

- a second step of fitting the partition 10 inside the housing 16 provided for receiving it,

- a third step of providing the cavity 18 and the protrusion 19 on the inside of the internal face 12 of the header 3, this step advantageously making it possible to immobilize the partition 10 in the desired position, for example within the partition plane P2, avoiding any pivoting of the partition inside the housing 16, including when there is an assembly clearance.

Advantageously, the assembly method may be completed by a fourth step of securing the cover 14 and the header plate 15, the partition 10 being interposed between the cover 14 and the header plate 15.

All of these provisions mean that the heat exchanger 1 thus obtained is free of leaks of refrigerant 5, internal and/or external.

It will be noted at this stage of the description that the present invention also covers all of the technically realizable possible combinations of the abovementioned embodiments.