FR3061952A1 - PLATE FOR HEAT EXCHANGER AND HEAT EXCHANGER COMPRISING SUCH PLATE - Google Patents

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 piece (20) for assembling said coupling edge (11), with at least one casing wall, said at least one fuse piece (20) being configured to being 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.

Description

@ Holder (s): VALEO THERMAL SYSTEMS Simplified joint-stock company.

® Agent (s): VALEO THERMAL SYSTEMS.

* 54) PLATE FOR HEAT EXCHANGER AND HEAT EXCHANGER INCLUDING SUCH A PLATE.

FR 3 061 952 - A1

@) 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 assembling this coupling edge (11), with at least one casing wall, said at least one fusible part (20) being configured for 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 intended to be assembled.

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Plate for heat exchanger and heat exchanger comprising such a plate

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

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

The automobile, like many other industrial fields, uses heat exchangers to provide the engine with optimal temperature operating conditions.

A vehicle interior air conditioning system also requires heat exchangers.

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

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

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

Due to the complexity of the heat exchangers and the small authorized dimensions, the assembly of the constituent elements of a heat exchanger is carried out, industrially, by brazing, and not by spot welding.

As shown in Figure 1, the plates 2, 3 of a heat exchanger 1 of the state of the art are thus typically assembled by brazing to the casing 5 of the exchanger 1, that is to say assembled by adding metal in a liquid state to 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 heat exchangers 1 are subjected to stresses in service that are both strong and of various kinds: thermomechanical constraints and chemical reactions with more or less aggressive environments.

In particular, we observe the existence of thermal shocks which are caused by a sudden and significant variation in temperature, for example when opening the valves fitted with sensors, making it possible to measure the temperature of the motor, and letting the water pass. engine cooling, cooler, in the engine air intake circuit, warmer.

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

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

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

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

The present invention therefore aims to overcome the drawbacks of the prior art and to meet the above constraints by proposing a plate for exchanger, simple in its design and in its operating mode, reliable and economical, which makes it possible to limit or even avoid, the appearance in the plate of rupture zones linked to thermal shocks.

Another object of the present invention is such a plate for a heat exchanger ensuring support on the opposite walls of the casing with a view to assembling it by brazing with an additional plate to form a conduit for circulation of a heat-transfer fluid.

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

To this end, the invention relates to a plate for a heat exchanger, said plate comprising an edge for coupling to another plate.

According to the invention, said edge comprises at least one fusible part for assembling this coupling edge, with at least one casing wall, said at least one fusible part 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 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 part of this plate delimiting an area of this plate for the circulation of a heat transfer fluid, this peripheral part having an upper face, a wafer and a lower face.

In different particular embodiments of this plate, each having its particular advantages and capable of numerous 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) strictly greater than the width (h ₂ ) of this coupling edge, in a middle part of said plate.

By way of illustration only, 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 fusible part is carried by a corner of the plate or a portion of the coupling edge close to this edge, because it is in these places of the plate that the rupture of the fusible part is best controlled and that the distance between the fusible element and the zone of the plate where it is sought to preserve the seal is the most important.

Furthermore, it is found that it is in the corners of the plate that the thermal stresses are the greatest. Positioning a fusible element in a corner of the plate thus ensures that it breaks, or breaks, as quickly as possible, that is to say from the first thermal cycling.

- two opposite corners of said plate each have a fusible piece for assembling said coupling edge, with the same housing wall or opposite housing walls.

In this latter embodiment, the points of support of the plate are thus advantageously formed on the opposite casing walls with a view to assembling this plate with an additional plate to form a conduit for circulation of a heat transfer fluid.

- said coupling edge, having a width (h ₂ ) in a median part of said plate, greater than or equal to a predetermined safety width (h _s ) for which a rupture of a fusible piece is not propagated beyond said edge of coupling, said edge comprises a fusible part in said middle part of said plate.

By way of illustration only, this predetermined safety width h _s is equal to 5 mm.

It is thus possible to position a fusible part outside a corner or an edge area close to this corner, for example in a middle part of the plate, provided that the width of the coupling edge is sufficient to avoid any propagation of a rupture of the fusible element beyond this edge.

- each fusible element has a predetermined weakening zone so as to cause it to separate from the coupling edge.

This configuration of the fusible member makes it possible to achieve another objective of the present invention, namely to obtain a “clear” rupture, or clean separation, of the fusible part from the coupling edge, so that this rupture does not tend to propagate beyond the coupling edge, that is to say in the region of the plate delimited 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 fusible part comprises a line of least mechanical resistance so as to break along this line.

This line of lower mechanical resistance therefore has a lower breaking strength than that of the metallic material surrounding it.

Advantageously, this line of least resistance is intended to cause the separation, preferably in a single piece, of the part of the fusible part linked to this line of least resistance.

For illustrative purposes only, these may be orifices arranged linearly, or even rectilinearly, to form a "line of openwork material".

Alternatively, or in addition, said or at least one fusible part comprises at least one notch.

For example, said fusible member has a first line of least resistance, two notches being located on either side of this line of least resistance.

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

each fuse piece has a tab connected by said predetermined weakening zone to the coupling edge, said tab being curved to present an assembly surface, preferably planar or substantially planar, intended to be assembled, by brazing, to a housing wall.

Said coupling edge being contained in a main plane (P), this assembly surface advantageously extends perpendicular 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 middle or substantially middle part of the plate. Alternatively, these fluid inlet and outlet are placed on the same side of the plate.

Such a plate comprises at least one fusible part on at least one of its sides. Preferably, fusible parts 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 head of the plate.

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 fusible part, preferably two fusible parts.

- each fuse part has an assembly surface on a casing 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 housing walls are made of a metallic material, preferably aluminum or an aluminum alloy.

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

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

Preferably, each fusible part 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 conduit for circulation of a heat-transfer fluid between these plates, at least one edge of the assembly thus formed, connected to a casing wall comprises, for each of these plates, at least one fusible part, said or at least some of said fusible parts placed on this edge being positioned opposite one another or being offset one in relation to the other.

In the latter case, the fusible parts are advantageously placed in the extension of one another. Advantageously, the offset of the fusible parts placed on the same corner of the plates thus assembled allows an increase in the assembly surface of each fusible part intended to be assembled by brazing to the casing wall.

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

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

For illustrative purposes only, the first fluid may be air and the second fluid may be a coolant.

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

Other advantages, aims and particular characteristics of the present invention will emerge from the description which follows, made, for explanatory purposes and in no way limitative, with reference to the appended drawings, in which:

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

- 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 thereof, fitted with a fusible element;

- Figure 4 is a schematic representation and in top view, of the corner of the plate of FIG. 3, an area of the plate capable of carrying a fusible piece, including a corner, is shown in dotted lines;

- Figure 5 shows the corner of the plate of Fig. 3, when subjected to thermal cycles;

- Figure 6 shows a partial view of two plates for superimposed heat exchanger for their 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 thus superimposed each comprising a fusible piece; the fusible parts on each corner being offset between the two plates by being placed in the extension of one another;

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

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

First, note that the figures are not to scale.

Figures 2 to 5 schematically show a plate 10 for heat exchanger 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 has a coupling edge 11 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 head of the plate.

This plate 10 also has a central rib 16 on the surface of its inner wall, which defines a projection to generate 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 protrusions 17 placed in the fluid circulation passage on its inner wall, which are intended to disturb the circulation of the fluid.

This plate 10 has longitudinal edges 18 of dimension just smaller than that of the upper and lower faces of the housing and transverse edges 13 of dimension equal to or substantially equal to that of the side walls of the exchanger housing (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 part of said ribs 14.

The first transverse edge 13 of the plate 10, receiving the fluid inlet and outlet, has a continuous rim for its assembly to a casing 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 guarantees sealing at the level of the fluid inlet and outlet.

Each fuse piece 20 here has a curved tab 21 having an assembly surface 22, and a predetermined weakening zone 23 connecting this curved tab 21 to the corresponding corner 19 of the plate 10 so as to allow the separation of this curved tab 21 from the corresponding corner 19.

The surfaces 22 for assembling the fusible parts 20 being flat, the opposite lateral walls of the casing are also plane at the level of the areas of assembly of these surfaces 22 for assembling with the casing walls.

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

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 expansion / contraction cycles of this plate

10.

In the present case, and purely by way of illustration, 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 level of the predetermined weakening zone 23.

After rupture of the fusible parts 20, the plate 10 for heat exchanger is separated on 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 bearing 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 represented, comprises at each of its opposite corners 19, two parts 20, 25 fuses.

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

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

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

The plate 30 having a length (L) and a width (h), these fluid inlet and outlet 31,32 are placed on the length (L) at a distance from the lateral edges of the plate corresponding to L / 2, or substantially L / 2.

Protrusions 33 make it possible to disrupt the circulation of the fluid while ribs 34 give fluid flow passages a sinuous path having half-turns between the fluid inlet and outlet 31,32.

This plate 30 has parts 35-38 fuses on both sides of it extending in a transverse direction.

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

This plate 40 has an inlet 41 for fluid and an outlet 42 for fluid 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 fusible 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 intended to be brazed to a casing wall.

The sealing of the fluid inlet and outlet being ensured by a collar, the side 43 can alternatively receive fusible parts 44.

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Claims (15)

1. Plate for heat exchanger, said plate comprising an edge (11) for coupling to another plate, characterized in that said edge comprises at least one fusible part (20) for assembling this edge (11) d 'coupling, with at least one housing wall, said at least one fusible part (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 housing wall on which it is intended 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) strictly greater than the width (h ₂ ) of said edge (11) of coupling in a median part of said plate. 3. Plate according to claim 1 or 2, characterized in that two opposite corners (19) of said plate each comprises a part (20) fusible for the assembly of said edge (11) of coupling, with the same housing wall or opposite casing walls. 4. Plate according to any one of claims 1 to 3, characterized in that said edge (11) of coupling, having a width (h ₂ ) in a median part of said plate, greater than or equal to a predetermined width of safety for which a rupture of a fusible part is not propagated beyond said edge (11) of coupling, said edge (11) comprises a part (20) fusible in said middle part of said plate. 5. Plate according to any one of claims 1 to 4, characterized in that each piece (20) fuse has a predetermined zone (19) of weakening so as to cause its separation from the edge (11) of coupling. 6. Plate according to claim 5, characterized in that said or at least one fuse part (20) comprises a line (23) of lower mechanical resistance. 7. Plate according to claim 5 or 6, characterized in that said or at least one fuse part (20) 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 an outlet (32) of fluid, 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 an inlet (14) of fluid and an outlet (15) of fluid placed at the head of plate. 11. Plate according to claim 10, characterized in that said first side has a continuous rim and the opposite side of said plate to said first side, comprises at least one fuse part (20). 12. Plate according to any one of claims 1 to 11, characterized in that each fuse part (20) has a surface (22) for assembly intended to be assembled to a casing wall, the longitudinal dimension of which is 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 (11) of coupling of these plates being intended to be assembled to delimit a conduit for circulation of a heat transfer fluid between these plates , each coupling edge (11) comprising at least one fusible part (20), said fusible parts (20) being arranged on the edges (11) of said plates so that after assembly thereof, two parts (20 ) fuses belonging to separate plates, are placed opposite one another or are offset from 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 conduit for circulation of a heat transfer fluid between these plates, at least one edge of the assembly thus formed, connected to a casing wall comprises, for each of these plates, at least one fusible part (20), said or at least some of said fusible parts placed on this edge being positioned opposite one of the 'other or being offset from each other. 1/4