EP3743667A1

EP3743667A1 - Heat exchanger plate, and heat exchanger comprising such a plate

Info

Publication number: EP3743667A1
Application number: EP18708332.4A
Authority: EP
Inventors: Jean-Pierre Galland; Nicolas Vallee; Yoann Naudin; Frédéric WASCAT; Eddie Sausset
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2018-01-23
Filing date: 2018-01-23
Publication date: 2020-12-02
Anticipated expiration: 2038-01-23
Also published as: US20210071961A1; WO2019145022A1; CN111886470A; CN111886470B; EP3743667B1

Abstract

The invention relates to a plate for a heat exchanger, said plate comprising an edge (11) for coupling to another plate. According to the invention, said edge comprises at least one fusible part (20) for the assembly of said coupling edge (11) with at least one housing wall, said at least one fusible part (20) being designed to be separated from the rest of said coupling edge by differential dilation/contraction between said plate and said at least one housing wall, on which it is to be assembled.

Description

Plate for heat exchanger and heat exchanger

heat comprising such a plate

The present invention relates to a plate for a heat exchanger, in particular for a brazed plate heat exchanger on the walls of the casing.

It also relates to a heat exchanger comprising at least one such plate.

The automobile, like many other industries, uses heat exchangers to provide the engine with optimum temperature conditions.

An air conditioning system in a vehicle interior also requires heat exchangers.

It is thus known to equip a vehicle with a plurality of heat exchangers, each of which is equipped with a set of plates forming a heat exchange beam between a first fluid and a second heat transfer fluid, this exchange beam being housed. in a crankcase.

For several decades, aluminum has become the constituent metal of heat exchangers and has, in fact, replaced other metals such as copper, implemented because of their good thermal properties.

Aluminum allows a significant weight gain and aluminum alloys have a quite satisfactory thermal conductivity while having a good resistance to corrosion.

Because of the complexity of the heat exchangers and the small dimensions allowed, the assembly of the constituent elements of a heat exchanger is produced, industrially, by brazing, and not by spot welding.

As shown in FIG. 1, the plates 2, 3 of a heat exchanger 1 of the state of the art are thus typically assembled by soldering to the casing 5 of the exchanger 1, that is to say assembled by a supply of metal in the liquid state on the metal parts to be assembled.

These plates 2, 3 being brazed over their entire surface in contact with the housing walls 5, the metal thus provided forms a continuous line 4.

This results in a lack of flexibility of the assembly thus obtained.

However, it is known that the heat exchangers 1 are subjected to loads of service at the same time strong and of various natures: constraints thermomechanical and chemical reactions with more or less aggressive environments.

In particular, we observe the existence of thermal shocks that are caused by a sudden and significant change in temperature, for example when opening the valves equipped with sensors, to measure the engine temperature, and letting the water pass Cooling the engine, cold, into the engine air intake system, warmer.

These thermal shocks lead to expansion / contraction phenomena of the plates 2, 3 of the heat exchanger 1, called thermal cycles.

However, the lack of flexibility of these plates 2, 3 and brazed, generates significant stresses, which can lead to the appearance of rupture zones in the plates 2, 3.

It is then observed that these rupture zones can generate leaks of heat transfer fluid.

There is therefore a pressing need for a heat exchanger plate whose original design ensures greater flexibility of the plate.

The present invention therefore aims to overcome the disadvantages of the prior art and to meet the above constraints by proposing a heat exchanger plate, simple in its design and in its operating mode, reliable and economical, which can limit or to avoid, the appearance in the plate of rupture zones related to thermal shocks.

Another object of the present invention is such a plate for heat exchanger ensuring a bearing on the opposite walls of the casing for its assembly by soldering with a complementary plate to form a circulation duct of a heat transfer fluid.

The present invention also relates to a heat exchanger comprising at least one such exchanger plate, so as to have enhanced reliability.

For this purpose, the invention relates to a plate for a heat exchanger, said plate comprising a coupling edge to another plate.

According to the invention, said edge comprises at least one fuse piece for assembling this coupling edge, with at least one casing wall, said at least one fuse piece being configured to be separated from the rest of said coupling edge by differential expansion / contraction between said plate and said at least one housing wall on which it is intended to be assembled.

The plate for heat exchanger can have any shape such as square, rectangular, ... By "edge" of the plate is meant the peripheral portion of this plate defining an area of this plate for the circulation of a heat transfer fluid, this peripheral portion having an upper face, a wafer and a lower face.

In various particular embodiments of this plate, each having its particular advantages and susceptible to many possible technical combinations:

said or at least one of said fusible parts is carried by a corner of said plate or by a portion of the coupling edge, close to this corner, said portion having a width (hi) greater than the width (h ₂ ) of this coupling edge, in a median portion of said plate.

As a purely illustrative example, for a width h ₂ of the order of 3 mm, this part may extend over a distance of between 0 and 30 mm, if a minimum width hi of 5 mm is guaranteed in this part.

Preferably, each fuse piece is carried by a corner of the plate or a portion of the coupling edge close to this edge, because it is in these parts of the plate that the rupture of the fuse piece is best controlled and that the distance separating the fusible part from the zone of the plate where it is sought to preserve the seal is the most important.

Moreover, it is found that it is in the corners of the plate that the thermal stresses are the most important. A positioning of a fuse piece in a corner of the plate thus ensures a break, or "break" thereof, as quickly as possible, that is to say from the first thermal cycling.

- Two opposite corners of said plate each comprises a fuse piece for assembly of said coupling edge, with the same housing wall or opposite housing walls.

In this latter embodiment, it thus advantageously forms the bearing points of the plate on the opposite housing walls for the assembly of this plate with a complementary plate to form a circulation duct of a heat transfer fluid.

said coupling edge, having a width (h ₂ ) in a median portion of said plate, greater than or equal to a predetermined safety width (h _s ) for which a fuse break is not propagated beyond said edge coupling, said edge has a fuse piece in said middle portion of said plate.

For purely illustrative purposes, this predetermined safety width h _s is equal to 5 mm. It is thus possible to position a fuse piece outside a corner or an area of the edge close to this corner, for example in a middle part of the plate, provided that the width of the coupling edge is sufficient to prevent any propagation of a rupture of the fuse piece beyond this edge.

each fuse piece comprises a predetermined zone of weakening so as to cause its separation from the coupling edge.

This configuration of the fuse piece makes it possible to achieve another objective of the present invention, namely to obtain a "clean" break, or clean separation, of the fuse piece from the coupling edge, so that this break does not tend to propagate beyond the coupling edge, that is to say in the region of the plate defined by this edge and in which is intended to circulate a heat transfer fluid.

Said coupling edge extending in a main plane (P), the predetermined weakening zone is advantageously contained in this main plane (P), preferably belonging to this edge.

Advantageously, said or at least one fuse piece comprises a line of lesser mechanical resistance so as to break along this line. This line of lesser mechanical strength therefore has a lower breaking strength than the metal material surrounding it.

Advantageously, this line of least resistance is intended to cause the separation, preferably in one piece, of the part of the fuse piece related to this line of least resistance.

As a purely illustrative example, they may be orifices arranged linearly or rectilinearly to form a "line of perforated material".

Alternatively, or in addition, said or at least one fuse piece comprises at least one notch.

By way of example, said fuse piece comprises a first line of least resistance, two notches being located on either side of this line of least resistance.

Still alternatively, this line of least resistance is obtained by local thinning.

each fuse piece comprises a tab connected by said predetermined zone of weakening to the coupling edge, said tab being curved to present an assembly surface, preferably flat or substantially flat, intended to be assembled, by soldering, to a crankcase wall.

Said coupling edge being contained in a main plane (P), this joining surface advantageously extends perpendicularly to the main plane (P). said plate comprises a fluid inlet and a fluid outlet, each of the fluid inlet and outlet having a collar.

For purely illustrative purposes, these fluid inlet and outlet are placed in a median or substantially median portion of the plate. Alternatively, these fluid inlet and outlet are placed on the same side of the plate.

Such a plate has at least one fuse piece on at least one of its sides. Preferably, fusible pieces are placed on two of the opposite sides of this plate.

Alternatively, a first side of this plate comprises a fluid inlet and a fluid outlet placed at the plate head.

In this configuration of the plate, this first side has a continuous rim and the opposite side of said plate to said first side comprises at least one fuse piece, preferably two fusible pieces.

- Each fuse piece has an assembly surface on a housing wall whose longitudinal dimension is between 3 and 20 mm.

said plate is in one piece and made of a metallic material such as aluminum or an aluminum alloy.

The casing walls are made of a metallic material, preferably aluminum or an aluminum alloy.

The present invention also relates to a pair of exchanger plates as described above, the coupling edges of these plates being intended to be assembled to delimit a heat transfer fluid circulation duct between these plates, each coupling edge comprising at least one fusible piece, said fusible parts being arranged on the edges of said plates so that after assembly thereof, two fusible parts belonging to distinct plates, are placed facing one another or are offset one with respect to the other.

In the latter case, the fusible parts are advantageously placed in the extension of one another.

Preferably, each fuse piece is placed only in a corner of said plates.

The present invention also relates to a plate heat exchanger comprising two plates as described above, these two plates being assembled together to delimit a heat transfer fluid circulation duct between these plates, at least one edge of the assembly and formed, connected to a housing wall comprises, for each of these plates, at least one fuse piece, said or at least some of said fuse pieces placed on this edge being positioned opposite one another or being offset relative to each other.

In the latter case, the fusible parts are advantageously placed in the extension of one another. Advantageously, the offset fusible parts placed on the same corner of the plates thus assembled allows an increase in the assembly area of each fuse piece to be assembled by soldering to the housing wall.

In particular, it relates to a brazed plate heat exchanger.

This heat exchanger may comprise a heat exchange beam between a first fluid and a second fluid, and a casing inside which this exchange beam is placed.

As a purely illustrative example, the first fluid may be air and the second fluid may be a coolant.

The second fluid may be for example a mixture of water and glycol. For example, the air can be charged air.

Other advantages, aims and particular features of the present invention will emerge from the description which follows, made for an explanatory and non-limiting purpose, with reference to the appended drawings, in which:

- Figure 1 is a partial and enlarged view of a heat exchanger of the state of the art, showing in particular a brazed assembly line between a plate of the exchanger and the corresponding wall of the housing;

- Figure 2 is a perspective view of a plate for heat exchanger according to a first embodiment of the invention;

Figure 3 is a partial and enlarged view of the plate of FIG. 2 showing a corner of it, equipped with a fuse piece;

4 is a diagrammatic representation in plan view of the corner of the plate of FIG. 3, an area of the plate capable of carrying a fuse, including a corner, is shown in dotted line;

Figure 5 shows the corner of the plate of FIG. 3, when subjected to thermal cycling;

Figure 6 shows a partial view of two superimposed heat exchanger plates for assembly to form a pair of plates;

- Figure 7 is a partial view of a pair of plates, the corners of the lower transverse edges of these plates and superimposed each having a fuse piece; the fusible parts on each corner being offset between the two plates being placed in the extension of one another;

Figure 8 is a perspective view of a heat exchanger plate according to a second embodiment of the invention; - Figure 9 schematically shows a plate for heat exchanger according to a third embodiment of the invention;

First, we note that the figures are not scaled.

Figures 2 to 5 schematically show a heat exchanger plate 10 according to a first embodiment of the present invention.

This plate 10 which is in one piece, is for example made of aluminum or an aluminum alloy.

This plate 10 is of generally rectangular shape.

It comprises a coupling edge 1 1 and a concave region 12 delimited by this edge.

This plate 10 has on a first transverse edge 13, or side extending in a transverse direction, a fluid inlet 14 for introducing a fluid and a fluid outlet 15 for discharging the fluid, which are placed at the top of the plate.

This plate 10 also comprises a central rib 16 on the surface of its inner wall, which defines a projection for generating a separation on the surface of the inner wall of the plate 10 in order to define a "U" circuit between the inputs 14 and fluid outlet 15.

In addition, this plate 10 has a plurality of protuberances 17 placed in the fluid circulation passage on its inner wall, which are intended to disrupt the flow of fluid.

This plate 10 has longitudinal edges 18 of dimension just smaller than that of the upper and lower faces of the housing and the transverse edges 13 of dimension equal to or substantially equal to that of the side walls of the housing of the exchanger (not shown).

This plate 10 also has four corners 19, only one being shown in FIGS. 3 to 5. Each corner 19 defines an edge surrounding a portion of said ribs 14.

The first transverse edge 13 of the plate 10, receiving the fluid inlet and outlet, comprises a continuous flange for its assembly to a housing wall while the two corners 19 of the transverse edge opposite this first edge 13, each comprise a part 20 fuse.

The first transverse edge 13 of the plate 10 ensures sealing at the fluid inlet and outlet.

Each fuse piece here comprises a curved lug 21 having an assembly surface 22, and a predetermined weakening zone 23 connecting this curved lug 21 to the corresponding corner 19 of the plate 10 so as to allow the separation of this curved lug 21 corresponding corner 19. The assembly surfaces 22 of the fusible parts being flat, the opposite side walls of the housing are also flat at the assembly areas of these surfaces 22 of assembly with the housing walls.

This predetermined zone 23 of weakening is here obtained by cutting a part of the lateral edges of the body of the fusible part 20, these notches making it possible to generate a breaking primer.

These notches are here rectangular or substantially rectangular.

The depth of the notches is determined so that the separation is carried out after a few thermal cycles of expansion / contraction of this plate 10.

In the present case, and purely for illustrative purposes, the largest side of this notch is of a dimension less than or equal to 1 mm and its short side is of a dimension less than or equal to 0.5 mm.

Figure 5 shows, by numerical simulation, the good results obtained with this plate 10 for heat exchanger when it is subjected to thermal cycles.

It is observed that the stresses are concentrated at the predetermined attenuation zone 23.

After rupture of the fusible parts, the plate 10 for heat exchanger is separated at its sides comprising fusible parts.

Figures 6 and 7 illustrate the assembly of a plate 10 as described above, with another plate 24 to define a pair of plates delimiting between them a passage for the flow of a fluid. The elements of Figures 6 and 7 with the same references as those described in Figures 2 to 5, represent the same objects, which will not be described again below.

The side of this pair of plates 10, 24 thus shown comprises at each of its opposite corners 19, two parts 20, 25 fusible.

The two pieces 20, 25 fuses of each corner 19 of the pair each belong to a different plate 10, 24 and are offset relative to each other while being in the extension of one another.

Figure 8 is a perspective view of a heat exchanger plate 30 according to a second embodiment of the invention.

This plate 30 comprises a fluid inlet 31 and a fluid outlet 32, each of the fluid inlet and outlet having a collar and an oblong shape.

Since the plate 30 has a length (L) and a width (h), these fluid inlet and outlet 31, 32 are placed along the length (L) at a distance from the lateral edges of the plate corresponding to L / 2, or substantially L / 2. Protuberances 33 disrupt fluid flow while ribs 34 provide fluid flow passages with a sinuous path with half-turns between fluid inlet and outlet 31, 32.

This plate 30 has 35-38 fusible parts on both sides thereof extending in a transverse direction.

Figure 9 schematically shows a plate for heat exchanger according to a third embodiment of the invention.

This plate 40 has a fluid inlet 41 and a fluid outlet 42 placed on the same side of the plate, this side 43 extending in a transverse direction. Each of these fluid inlet 41 and outlet 42 has a collar and an oblong shape.

This plate 40 has a fuse piece 44 in each corner 45 on its side opposite to that 43 extending in a transverse direction where the fluid inlet and outlet are located.

This side 43 extending in a transverse direction has a continuous flange for brazing to a housing wall.

Sealing of the fluid inlet and outlet being provided by a collar, the side 43 may alternatively receive fusible parts 44.

Claims

1. Plate for heat exchanger, said plate comprising an edge (1 1) for coupling to another plate, characterized in that said edge comprises at least one fusible piece (20) for assembling said edge (1 1 ), with at least one casing wall, said at least one fuse piece (20) being configured to be separated from the rest of said coupling edge by differential expansion / contraction between said plate and said at least one casing wall on which it is destined to be assembled.

2. Plate according to claim 1, characterized in that said or at least one of said fusible parts is carried by a corner (19) of said plate or by a portion of said coupling edge, close to this corner (19), said portion having a width (hi) greater than strictly the width (h ₂ ) of said edge (1 1) of coupling in a middle portion of said plate.

3. Plate according to claim 1 or 2, characterized in that two opposite corners (19) of said plate each comprises a fusible piece (20) for assembling said coupling edge (1 1), with the same wall of crankcase or opposite crankcase walls.

4. Plate according to any one of claims 1 to 3, characterized in that said edge (1 1) of coupling, having a width (h ₂ ) in a middle portion of said plate, greater than or equal to a predetermined width safety device for which a break fuse piece is not propagated beyond said edge (1 1) of coupling, said edge (1 1) has a piece (20) fuse in said middle portion of said plate.

5. Plate according to any one of claims 1 to 4, characterized in that each part (20) fuse comprises a predetermined zone (19) of weakening so as to cause its separation from the edge (1 1) of coupling.

6. Plate according to claim 5, characterized in that said or at least one piece (20) fuse comprises a line (23) of lower mechanical strength.

7. Plate according to claim 5 or 6, characterized in that said or at least one piece (20) fuse comprises at least one notch.

8. Plate according to any one of claims 1 to 7, characterized in said plate (30) comprises a fluid inlet (31) and a fluid outlet (32), each of the fluid inlet and outlet having a collar.

9. Plate according to claim 8, characterized in that fusible parts (35-38) are placed on two of the opposite sides of said plate.

10. Plate according to any one of claims 1 to 7, characterized in that a first side (13) of said plate (10) comprises a fluid inlet (14) and a fluid outlet (15) placed at the top. plate.

1. A plate according to claim 10, characterized in that said first side comprises a continuous flange and the opposite side of said plate to said first side, comprises at least one piece (20) fuse.

12. Plate according to any one of claims 1 to 1 1, characterized in that each piece (20) fuse has an assembly surface (22) intended to be assembled to a housing wall, the longitudinal dimension is included between 3 and 20 mm.

13. Plate according to any one of claims 1 to 12, characterized in that said plate (10) is in one piece and made of a metallic material, such as aluminum or an aluminum alloy.

14. Pair of plates for heat exchanger according to any one of claims 1 to 13, the edges (1 1) of coupling of these plates being intended to be assembled to define a conduit for the circulation of a heat transfer fluid between these plates, each coupling edge (1 1) comprising at least one fusible piece (20), said fusible pieces (20) being arranged on the edges (1 1) of said plates so that after assembly thereof, two parts (20) fuses belonging to separate plates, are placed opposite each other or are offset relative to each other.

15. Plate heat exchanger comprising at least two plates according to any one of claims 1 to 13, said two plates being assembled together to delimit a heat transfer fluid circulation duct between these plates, at least one edge of the assembly thus formed, connected to a housing wall comprises, for each of these plates, at least one fusible part (20), said or at least some of said fusible pieces placed on this edge being positioned facing one of the other or being offset with respect to each other.