EP2294348A1

EP2294348A1 - Plate type heat exchanger, particularly for motor vehicles

Info

Publication number: EP2294348A1
Application number: EP09749869A
Authority: EP
Inventors: Anne-Sylvie Magnier-Cathenod; Jean-Sylvain Bernard; Carlos Martins
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2008-05-22
Filing date: 2009-05-20
Publication date: 2011-03-16
Anticipated expiration: 2029-05-20
Also published as: CN102084205B; CN102084205A; FR2931542A1; PL2294348T3; EP2294348B1; US9618280B2; WO2009141379A1; US20110108258A1

Abstract

A heat exchanger (10) comprises an alternating stack of first plates (12) and of second plates (14) respectively provided with first corrugations (16) separated from one another by a first spacing (P₁) and of second corrugations (18) separated from one another by a second spacing (P₂) which is different from the first spacing (P₁). This thus defines, between the plates, first circulation passages with a first passage cross section suited to a first fluid (F₁) which alternate with second circulation passages which have a second passage cross section suited to a second fluid (F₂). The invention applies particularly to heat exchangers for motor vehicles.

Description

Plate heat exchanger, in particular for motor vehicles

The invention relates to the field of heat exchangers, especially for motor vehicles.

It relates more particularly to a heat exchanger of the type comprising an alternating stack of first plates and second plates respectively provided with first undulations and second undulations to define, between the plates, first circulation channels for a first fluid which alternate with second circulation channels for a second fluid.

In such a heat exchanger, the first plates and the second plates are provided with aligned through openings which define ducts to allow the first fluid to feed the first circulation channels and the second fluid to feed the second circulation channels. .

Such a heat exchanger is generally made by soldering by tight assembly of respective raised edges of all the plates.

Stacked plate heat exchangers are used primarily as oil exchangers, for example for cooling engine oil or motor vehicle gearbox oil. They are also used for water condensers, in which a refrigerant is cooled by water, usually the cooling water of the engine.

The plates may have different geometric shapes, for example rectangles, _ and _e_ll_es _sont generally provided with reliefs intended to be brazed mutually to ensure the mechanical strength. These reliefs also serve to disturb the circulation of the fluid and to increase the heat exchange surface.

In most known solutions, the plates used are identical or symmetrical, so that the first circulation channels and the second circulation channels have identical passage sections.

It is also known, from EP 1 630 510, to provide stacked plates making it possible to have different passage sections for the first and second circulation channels, and therefore for the two fluids that exchange heat with each other. ,

The above publication teaches for this to provide symmetrical plates having different corrugations, for example a large wave alternating with two small waves. However, in this known solution, the small undulations never pass through the neutral line of the plate, that is to say by the average plane of the plate. As a result, each small corrugation does not come into contact with another small corrugation, which has the effect that the resistance to pressure is ensured only by the thickness of the plate, but these plate heat exchangers can in certain applications, fluids operating at high pressure, for example of the order of a hundred bars, requiring a mechanical strength at such pressure values, pass through them.

The object of the invention is in particular to overcome the aforementioned drawbacks.

Its main purpose is to provide a heat exchanger of the aforementioned type which makes it possible to adapt the respective passage sections of the first and second circulation channels to the two fluids used, in particular as regards their flow rates and physical properties.

The invention also aims to provide a heat exchanger of the aforementioned type offering a better resistance to the pressure of each of the first channels and the second circulation channels by a suitable configuration of the corrugations.

To this end, the invention proposes a plate heat exchanger, as defined in the introduction, in which the first undulations are distant from each other by a first pitch P ₁ , while the second undulations are distant from one another. not P ₂ , which is different from the first step, which allows the first channels and second channels to define respectively a first passage section and a second passage section different respectively adapted to the first fluid and the second fluid.

This adaptation is thus effected by an appropriate choice of the values of the first step and the second step.

The first corrugations are in principle identical to each other and the same is true for the second corrugations, which avoids having to produce different corrugations within the same plate, as is the case in the EP publication 1 630 510 supra.

Thus, by the choice of the values of the pitches P ₁ and P ₂ , it is possible to adapt the passage section of the first and second channels respectively to the first fluid and the second fluid depending on the properties of these two fluids.

The resistance to pressure of the first and second channels is ensured by making each time pass the corrugations by the neutral line of the respective plates, in particular by providing the corrugations of one and the same side of said neutral line.

In the detailed description which follows, made only by way of example, reference is made to the appended drawings, in which:

- Figure 1 is an exploded perspective view of a plate heat exchanger in a first embodiment of the invention;

FIG. 2 is a perspective view of a first plate of the heat exchanger of FIG. 1, the undulations of which are straight and spaced apart by a first pitch P ₁ ;

FIG. 3 is a perspective view of a second plate of the heat exchanger of FIG. 1, the undulations of which are straight and spaced apart by a second pitch P ₂ ;

- Figure 4 is a side view of a plate heat exchanger in a second. embodiment of the invention;

FIG. 5 is a perspective view of a first plate of the heat exchanger of FIG. 4, the corrugations of which are in chevron and spaced apart by a first step;

Pi;

- Figure 6 is a longitudinal sectional view of the first plate of Figure 5;

- Figure 7 is a longitudinal sectional view of a second plate of the heat exchanger of Figure 4; - Figure 8 is a sectional view, on an enlarged scale, along the line VIII-VIII of Figure 4;

Figure 9 is a partial section of the section of Figure 8 showing a second plate superimposed over a first plate;

Figure 10 is a partial section of the section of Figure 8 showing a first plate superimposed over a second plate;

FIG. 11 illustrates the brazing surfaces between the plates of FIG. 9; and

- Figure 12 illustrates the brazing surfaces between the plates of Figure 10.

The heat exchanger 10 shown in FIG. 1 comprises an alternating stack of first plates 12 and second plates 14 respectively provided with first corrugations

16 and second corrugations 18. This stack is comprised between two end plates, namely a bottom plate 20, which is closed, and an upper plate 22, which is provided with two tubes 24 and 26 for the inlet and the outlet. output of a first fluid Fi and two other pipes 28 and 30 for the entry and exit of a second fluid F ₂ .

The first plate 12 (FIG. 2) comprises a flat bottom 32, in the example of a generally rectangular shape, defining a neutral line through which the first undulations 16 pass. All the undulations pass through the bottom 32. In the example, these first undulations 16 propagate in a straight line parallel to a first direction Di, which extends obliquely with respect to the sides of the rectangle defined by the bottom 32 of the plate. In FIG. 2, the corrugations 16 are identical to each other and spaced apart by a first pitch Pi.

The bottom 32 is surrounded by a raised peripheral edge 34, in the form of draft, to allow its assembly to respective raised edges of second adjacent plates, as will be seen later.

Furthermore, the bottom of the plate comprises two bosses 36 and 38 provided along a long side of the rectangle and provided with respective openings 40 and 42. These two bosses are flat and raised relative to the plane defined by the bottom 32 of the plate. The bottom 32 has two other openings 44 and 46 along the other long side, the latter being formed directly in the bottom 32 of the plate. The openings 40, 42, 44 and 46 are circular.

The second plate 14 is made in a homologous manner. It comprises a flat bottom 48 defining a neutral line through which the second undulations 18 pass. These last propagate in a straight line parallel to a second direction D qui which extends obliquely with respect to the sides of the rectangle defined by the bottom 48. The corrugations 18 are parallel to each other and spaced apart by a second pitch P ₂ which is greater than the pitch Pi. As in the case of the first plate 12, the plate 14 is surrounded by a raised peripheral edge 50 flush to allow mutual assembly of the plates by interlocking and brazing their respective peripheral edges.

The corrugations of said first and second plates have, for example, a height, that is to say a dimension in the direction perpendicular to the extension plane of said plates, identical. The angle of engagement of said plates is thus the same for all the plates.

The choice of the height of said peripheral edges is made according to the value of the nesting angle and the material thickness of the plates to allow interlocking with contact of the raised peripheral edges of the adjacent plates during assembly said plates. The height of the corrugations is ¹ adapted to ensure contact from one plate to another without limiting the interlocking to ensure a constant nesting angle.

The flat bottom 48 has two bosses 52 and 54 provided along a long side of the rectangle and provided with respective openings 56 and 58. The bottom 48 also comprises two openings 60 and 62 arranged along the other long side rectangle, these openings being 'made directly in the bottom 48. The openings 56, 58, 60 and 62 are made circular. The assembly formed by the first plates and the second plates as well as by the end plates can be assembled by soldering in a single operation. Thus, a multiplicity of alternating channels for the circulation of the first fluid F1 which alternate with a multiplicity of circulation channels for the fluid F ₂ is defined. The tubing 24 is in line with the openings 40 and 60, which are aligned, to define a supply duct. The tubing 26 is in line with the openings 42 and 62, which are aligned, to define a supply duct. The tubing 28 is in line with the openings 46 and 58, which are aligned, to define a supply duct. Finally the tubing 30 is in line with the openings 44 and 56, which are aligned, to define a supply duct.

In the stack, the corrugations 16 of a first plate each intersect with the undulations 18 of the second adjacent plates, so that the first undulations and the second undulations intersect and come into contact with each other by vertices. respectively. These peaks are brazed during the brazing operation, thus ensuring better mechanical resistance of the plates to pressure.

Because the steps Pi and P ₂ are different, the passage sections defined by the first and second channels are different and can be adapted by appropriate choice of the pitch values Pi and P ₂ . Advantageously, the ratio Pi / P ₂ between the first pitch Pi and the second pitch P ₂ is between 1 and 6 with P1 P2. Advantageously, this ratio is a fractional number, for example ^{1 to} ₁ 2/3, etc.

In the example of Figure 1, this ratio is ¹ A. The difference of the passage sections of the circulation channels will be further explained with the second embodiment of FIGS. 4 to 12.

In this second embodiment, the elements homologous to those of the first embodiment are designated by the same numerical references increased by 100.

Figure 4 is a side view of the heat exchanger 110 of the second embodiment.

FIG. 5 shows a first plate 112 which is homologous to the plate 12 of FIG. 2, the main difference being that the corrugations 116 propagate in chevron, that is to say that they have nested V-shapes one in the others. These corrugations are identical to each other and spaced apart by a pitch Pi as can be seen in FIG. 5 and as can also be seen in the section of FIG. 6. The corrugations 116 pass through the neutral line defined by the bottom 132 of the plate 116.

The second plate 114 is not shown in perspective, but only in section in FIG. 7. It comprises second corrugations 118 which propagate in chevron but with a different orientation from that of the corrugations 116 of the plate 112. Indeed, the respective chevrons of plates 112 and 114 are propagated in mutually opposite directions so that the first undulations and the second undulations intersect and contact respective vertices. These respective tops are intended to be soldered during soldering of stacking the plates to ensure better mechanical strength.

As can be seen in the sectional view of FIG. 7, the corrugations 118 are spaced from each other by a second pitch P ₂ which, in the example, is twice the pitch Pi. As a result, the ratio Pi on P ₂ is also ¹ A. as in the first embodiment.

The sectional view of FIG. 8 shows the alternating stack of plates 112 and 114, between a lower plate 120 and an upper plate 122 which carries tubings 124, 126, 128 and 130 (see also FIG. 4). Figure 8 also shows the passage sections of the respective flow channels defined between the plates 112 and 114.

FIG. 9 shows a first plate 112 with corrugations 116 spaced by a pitch Pi, on which is placed a second plate 114 with corrugations 118 spaced apart by a pitch P ₂ . It can be seen that the corrugations 116 and 118 come into contact with each other by their respective vertices, once in three for the corrugations 116 and once in two for the corrugations 118, and this thanks to the choice of the ratio P1 / P2. Between the plates 112 and 114 are defined first traffic channels Ci whose passage section Si is marked by hatching.

FIG. 10 shows the inverted configuration in which the first plate 112 is disposed above a second plate 114. In this case, second circulation channels C ₂ are defined between these plates, the passage section S _{2 of which} is materialized. by hatching. It is seen, by a comparison of FIGS. 9 and 10, that the passage section If first channels Ci (Figure 9) is greater than the passage section S ₂ of the second channels C ₂ (Figure 10). Thus, by appropriate choice of pitch values P ₁ and P ₂ , the values of these passage sections can be varied and adapted to the fluid in question.

For example, in the case of a condenser traversed by a high-pressure refrigerant (typically 110 bars) and by low-pressure cooling water (typically from 1 to 2 bars), the refrigerant will be passed through. by the weakest passage section, that is to say by the channels C ₂ (Figure 10). In contrast, the fluid operating at lower pressure, here water, will pass through the largest passage section, that is to say, through the passage channels Ci (Figure 9). In this case, the water corresponds to the fluid F1 fed by the tubing 124 and discharged through the tubing 126, whereas the refrigerant then corresponds to the fluid F ₂ supplied by the tubing 128 and discharged through the tubing 130. first passage section S ₁ and the second passage section S ₂ which is the smallest is adapted to that of the first fluid F ₁ and the second fluid F ₂ which operates at the highest pressure.

Figure 11 shows the brazing surfaces SBi enter the plates 112 and 114 in the configuration of Figure 9, while Figure 12 shows the brazing surfaces SB ₂ between the first plate 112 and the second plate 114 in the configuration of the figure 10.

In the surfaces SBi of FIG. 11 are more limited than the surfaces SB ₂ of FIG. 12. The fluid with lower pressure, here the fluid F1, can propagate between brazing surfaces SBi as represented by the arrow of FIG. 11.

On the other hand, in the case of FIG. 12, the higher pressure fluid F ₂ can propagate between the brazing surfaces SB2 as shown by the arrow.

In the case of Figure 11, the brazing surfaces are more limited and the passage sections. more extensive, allowing the passage of a fluid at lower pressure.

Conversely, in the case of Figure 12, the brazing surfaces are wider, which allows a better pressure resistance for the passage of a fluid at higher pressure.

The invention is capable of numerous variants, particularly with regard to the general shape of the plates, the shape and the respective pitch of the corrugations of the different plates.

The invention finds a preferential application to heat exchangers for motor vehicles, including condensers traversed by a refrigerant and cooled by water.

Claims

claims

A heat exchanger comprising an alternating stack of first plates (12; 112) and second plates (14; 114) respectively provided with first undulations (16; 116) and second undulations (18; 118) for defining, between the plates, first circulation channels (C ₁ ) for a first fluid (F ₁ ) which alternate with second circulation channels (C ₂ ) for a second fluid (F ₂ ), characterized in that that the first undulations (16; 116) are distant from each other by a first pitch (P ₁ ) while the second undulations (18; 118) are distant from each other by a second pitch (P ₂ ), which is different from first step (P ₁ ), which allows the first channels (C ₁ ) and the second channels (C ₂ ) to respectively define a first passage section (S ₁ ) and a second passage section (S ₂ ) different adapted to first fluid (F ₁ ) and the second fluid (F ₂ ),

2. Heat exchanger according to claim 1, characterized in that the first plate (12; 112) comprises a plane bottom (32; 132) defining a neutral line through which the first undulations (16; 116) pass.

3. Heat exchanger according to one of claims 1 and

2, characterized in that the second plate (14; 114) has a planar bottom (48; 148) defining a neutral line through which the second undulations (18; 118) pass,

4. Heat exchanger according to one of claims 1 to

3, characterized in that the first undulations (16) propagate in a straight line parallel to a first direction (D ₁ ) and in that the second undulations (18) propagate in a straight line parallel to a second direction (D ₂ ), extending angularly with respect to the first direction (D1), so that the first undulations and the second undulations intersect and are in contact with respective vertices.

5. Heat exchanger according to one of claims 1 to 3, characterized in that the first corrugations (116) propagate in chevrons and in that the second undulations

(118) propagate in chevrons in mutually opposite directions, so that the first undulations and the second undulations intersect and contact respective vertices.

6. Heat exchanger according to one of claims 1 to 5, characterized in that the ratio (P ₁ ZP ₂ ) between the first pitch (P ₁ ) and the second pitch (P ₂ ) is between 1 and 6, with P ₁ <P ₂ .

7. Heat exchanger according to claim 6, characterized in that the ratio (P ₁ ZP ₂ ) between the first step (P ₁ ) and the second step (P ₂ ) is a fractional number, for example 1Z2, 2Z3, etc. .

8. Heat exchanger according to one of claims 1 to 1, characterized in that the first plates (12; 112) and the second plates (14; 114) are each provided with a raised peripheral edge (34; 134; 50; 150) undercut to allow the plates to be interconnected by interlocking and brazing their respective peripheral edges.

9. Heat exchanger according to one of claims 1 to 8, characterized in that the first plates (12; 112) and the second plates (14; 114) are of generally rectangular shape.

10. Heat exchanger according to one of claims 1 to

9, characterized in that the first plates (12; 112) and the second plates (14; 114) are provided with openings (40, 42, 44, 46; 56, 58, 60, 62; 140, 142, 144, 146; 156, 158, 160, 162) for the passage of the first fluid (F ₁ ) and the second fluid (F ₂ ).

11. Heat exchanger according to one of claims 1 to

10, characterized in that it comprises a closed first end plate (20; 120) and a second end plate (22; 12) provided with two tubings (24,26; 124,126) for the inlet and the outlet of the first fluid (F ₁ ) and two other manifolds (28, 30; 128, 130) for the inlet and the outlet of the second fluid (F ₂ ).

12. Heat exchanger according to one of claims 1 to

11, characterized in that that of the first passage section (S ₁ ) and the second passage section (S ₂ ) which is the smallest is adapted to that of the first fluid (F ₁ ) and the second fluid (F ₂ ) which operates at the highest pressure.

13. Heat exchanger according to one of claims 1 to

12, characterized in that it is in the form of a condenser able to be traversed by a refrigerant and a cooling fluid.