EP2473809A1

EP2473809A1 - Heat exchanger

Info

Publication number: EP2473809A1
Application number: EP10747858A
Authority: EP
Inventors: Christophe Denoual; Jimmy Lemee
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2009-08-31
Filing date: 2010-08-31
Publication date: 2012-07-11
Anticipated expiration: 2030-08-31
Also published as: US9494369B2; FR2949554B1; FR2949554A1; CN102597680A; CN102597680B; EP2473809B1; WO2011023825A1; US20120247145A1

Abstract

The invention relates to a heat exchanger for exchanging heat between a first (HP) and a second (BP) fluids. According to the invention, said exchanger comprises a plurality of modules (15,15a,15b,15c) respectively including an upper plate (17) and a lower plate (19) assembled so as to define, between said plates (17,19), an inner cavity (21) forming a first circulating channel for the first fluid (HP), wherein said exchanger further comprises a housing (3) in which said modules (15,15a,15b,15c) are assembled in order to form said exchanger while defining spaces (33) between said modules, said spaces forming second circulation channels for the second fluid (BP).

Description

Heat exchanger

The invention relates to a heat exchanger especially for a motor vehicle, such as an internal exchanger in an air conditioning circuit.

There are now known heat exchangers for motor vehicles consisting of a bundle of tubes arranged in parallel on one or more rows, these tubes being intended for the circulation through the exchanger of a coolant.

Heat exchangers are also known comprising a plurality of superimposed plates configured to define fluid circulation channels for heat exchange.

However, such exchangers have many components, especially for sealing and assembly, which can also be long and expensive. Furthermore, the structure of such an exchanger must provide a seal between each fluid flow channel but also between these channels and the environment surrounding the exchanger. This imposes a structure and brazing lines that complicates the manufacture and assembly of such an exchanger.

The invention therefore aims to overcome these disadvantages of the prior art by providing a heat exchanger at a lower cost based on a simple structure with a reduced number of components, to reduce clutter and facilitate assembly of such an exchanger while optimizing its performance.

To this end, the invention relates to a heat exchanger between a first and a second fluid, characterized in that it comprises a housing inside which is disposed a plurality of modules respectively comprising an upper plate and a lower plate assembled by defining between said plates an inner cavity forming a first circulation channel for the first fluid, and in that at least a second circulation channel for the second fluid is delimited by the housing and a space between said modules.

Such a heat exchanger with a simple structure reduces the number of components while ensuring good performance of the exchanger.

The exchanger may further comprise one or more characteristics following, taken separately or in combination:

- The upper and lower plates of a module respectively have at least one connecting portion cooperating with an adjacent adjacent connecting portion of a contiguous module or the housing, for assembling and sealing said modules relative to the housing (body and cover) , and in that

said connecting portions form bumps on the outer surfaces of the upper and lower plates, said bumps extending respectively towards the associated adjacent connection portions, it is understood here that the upper and lower plates are symmetrical,

said connecting portions form recesses on the internal surfaces opposite the upper and lower plates forming a module,

a predetermined number of connection portions are aligned with a connection portion of the housing having an introduction / discharge orifice of the first fluid, and in that

said aligned connection portions respectively have an orifice, all of said orifices communicating with each other so as to define a channel for introducing / discharging the first fluid,

said plates respectively have two connecting portions disposed on either side of said plate on a common diagonal of said plate,

said plates respectively have a parallelepipedal general shape with two notches respectively formed on two opposite edges of said plate,

the housing has an orifice for introducing the second fluid at the orifice for discharging the first fluid, and an orifice for discharging the second fluid at the orifice for introducing the first fluid, for circulation; against the current of the first and second fluids, the housing comprises a housing body in which said modules are stacked, said body being closed by a cover disposed above said modules and fixed to the body by means of hooking tabs,

the housing is made in the form of two assembled half-housings,

the heat exchanger comprises fins disposed in the interior cavity which delimits the first circulation channel and / or in the space defined between said modules which delimits the second circulation channel.

The invention also relates to the use of a heat exchanger comprising any of the features described above, as an internal exchanger and placed within an air conditioning loop to heat exchange between a high pressure branch and a low pressure branch of said loop.

Finally, the invention also covers an air conditioning loop for a motor vehicle comprising a condenser or gas cooler, an expansion member, an evaporator and a compressor traversed in this order by the same refrigerant, said air conditioning loop comprises a high branch. pressure which starts at the compressor outlet and ends at the inlet of the expansion member, and a low pressure branch which starts at the outlet of the expansion member and ends at the inlet of the compressor characterized in that it comprises exchanger heat as described above, said first circulation channel is placed in the high pressure branch and said second circulation channel is placed in the low pressure branch.

The first fluid is a fluid at high pressure and high temperature and the second fluid is a fluid at low pressure and low temperature, the first fluid and the second fluid being identical, for example a refrigerant such as R134A or carbon dioxide , which circulates within a closed circuit or air conditioning loop.

Other features and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawings which may be used to better define the invention, among which :

- Figure 1 is a sectional view (AA visible in Figure 2) of a heat exchanger thermal device according to the invention,

FIG. 2 is a partially exploded view of the exchanger of FIG. 1;

FIG. 3 represents plates forming a module of the exchanger of FIG. 1, and

FIG. 4 is an alternative embodiment of a housing of the exchanger of FIG. 1.

In these figures, identical elements bear the same references.

FIG. 1 illustrates a heat exchanger 1 for example for a motor vehicle between a first fluid to be heated or cooled and a second fluid intended to absorb or give heat to the first fluid.

In the embodiment described, the first fluid HP (for high pressure) is a fluid to be cooled at high pressure and high temperature and the second fluid BP (for low pressure) is a fluid at low pressure and low temperature intended to absorb the heat of the first HP fluid.

According to a first embodiment illustrated in FIGS. 1 and 2, the exchanger 1 comprises a housing 3 comprising a housing body 3a and a cover 3b fixed to the housing body 3a. For this purpose, the housing body 3a has a plurality of fastening lugs 5 tight on the lid 3b once the exchanger 1 assembled. The body 3a is made by a stamping process. The plurality of attachment tabs 5 extend beyond a circumferential edge. In contrast to the hooking tabs 5 with respect to the circumferential edge, the body 3a is closed by a bottom through which passes an insertion orifice and an outlet orifice. The hooking tabs 5, the circumferential edge and the bottom are unitary, in that they are made from the same strip. The volume delimited by the circumferential edge and the bottom delimit a space which receives modules 15 stacked flat in this space.

In addition, the housing 3 has introducer ports for the first fluid HP and BP, and discharge ports for the first fluid HP and BP. For example, the housing body 3a has an inlet port 7 for the first fluid HP and an outlet port 9 for the second LP fluid, and the lid 3b has an inlet port 1 1 for the second LP fluid. and an exhaust port 13 for the first HP fluid. The introduction orifices 7 and discharge 13 of the first fluid HP are sealingly connected to a supply circuit (not shown) of the first HP fluid. Likewise, the introduction orifices 11 and the evacuation ports 9 of the second fluid BP are sealingly connected to a supply circuit (not shown) of the second fluid BP.

The housing 3, and more particularly the body 3a of the housing, houses a plurality of substantially identical modules 15 superimposed in the housing 3 and fixed in the housing 3 for example by brazing.

Referring to the example of FIG. 1, three modules 15 are assembled in the housing 3:

a lower module 15a disposed at the bottom of the housing 3,

an upper module 15b disposed on the top and

an intermediate module 15c between the lower modules 15a and 15b.

Of course, it is possible to have several intermediate modules 15c between the lower modules 15a and 15b.

A module 15 comprises an upper plate 17 and a lower plate 19, shown in more detail in FIG. 3. The upper 17 and lower 19 plates are, for example, generally parallelepiped-shaped metal plates having a small thickness of between 0.5 and 1.5. mm. At the angle of the short side (hereinafter edge 39) and the long side of the parallelepipedal shape of the plates is present an outgrowth which extends in the same plane as the plate. This protrusion has a rounded contour and supports connecting portions 27a and 27b (at each end but in the diagonal of the plate). Next to this protrusion and the rest of the small side or edge 39, it is found that the contour of the plate is inclined towards the orifices placed on the opposite edge. This constitutes a notch whose function is to distribute the fluid in the spaces between the modules 15. When the lower 15a, upper 15b and intermediate 15c modules are housed in the body 3a, the inclined contours delimit, with the inner wall of the body 3a and the lid 3b, an intake chamber dedicated to the low pressure fluid BP. The existence of the inclined contour makes it possible to release a sufficient volume so that the introduction orifice 11 is not obstructed by the upper module 15b. These upper plates 17 and lower 19 are assembled by defining between them an inner cavity 21 (Figure 1). For this, the contour 23 of the upper plates

17 and lower 19 (Figure 3) may be raised relative to the interior of the plate concerned. The raised contours 23 of two upper 17 and lower 19 plates are then contiguous so as to define the inner cavity 21 (Figure 1).

Alternatively, only one of the two plates (lower or upper) of the same module may comprise a raised contour, thus delimiting the inner cavity 21.

This inner cavity 21 forms a first circulation channel of the first fluid HP. In this example with three modules 15, the exchanger 1 thus comprises three first channels. The first channels thus formed are parallel to each other and have, for example, a height of 1 to 1.5 mm.

Vane 25 may be disposed in these first channels to improve heat exchange. These fins take the form of a turbulence plate folded accordion.

In addition, the heat exchanger 1 is assembled via connection portions on the housing 3 and on the modules 15. These connection portions make it possible to assemble the modules 15 with each other and with the housing 3 by cooperating with portions associated adjacent connection of a neighboring module or the housing 3.

More precisely,

the bottom of the housing body 3a in contact with the lower module 15a has at least one connecting portion 27 (FIG. 1),

the cover 3b in contact with the upper module 15b also has at least one connecting portion 27 (FIG. 2), and

- Each module 15 has at least one connecting portion 27, more specifically, each upper plate 17 and each lower plate 19 has at least one connecting portion 27a and 27b respectively placed at each end of the plate, at the outgrowth present on the short side of the latter (Figure 3). In the example illustrated in FIGS. 1 and 2, the bottom of the housing body 3a and the cover 3b respectively comprise a connecting portion 27. These connecting portions 27 respectively comprise the introduction orifice 7 of the first fluid HP, and the discharge port 13 of the first fluid HP. The upper plates 17 and lower 19 comprise a first connecting portion 27a and a second connecting portion 27b (Figure 3).

As can be seen in FIGS. 1 and 2, the first connection portions 27a of the modules 15 are aligned with each other and with the connecting portion 27 of the housing body 3a. Similarly, the second connecting portions 27b of the modules 15 are aligned with each other and with the connecting portion 27 of the cover 3b.

So,

- The connecting portion 27 of the housing body 3 a cooperates with an associated connecting portion 27a of the lower plate 19 of the lower module 15a - the connecting portions 27a and 27b of the upper plate 17 of the lower module 15a cooperate with the connecting portions 27a and 27b associated with the lower plate 19 of the intermediate module 15c,

- The connecting portions 27a and 27b of the upper plate 17 of the intermediate module 15c cooperate with the connecting portions 27a and 27b associated with the lower plate 19 of the upper module 15b, and

- A connecting portion 27b of the upper plate 17 of the upper module 15b cooperates with the associated connecting portion 27 of the lid 3b.

In addition, the connecting portions 27a and 27b of the modules 15 also have orifices or holes for the passage of the first HP fluid.

Thus, the orifices of the first connecting portions 27a communicate with each other and with the introduction orifice 7 of the first fluid HP. This defines an introduction channel of the first HP fluid.

Similarly, the orifices of the second connecting portions 27b communicate with each other and with the discharge orifice 13 of the first fluid HP. This defines a drain channel of the first HP fluid. Of course, the connecting portions 27, 27a and 27b cooperate with each other, for example by brazing, in a sealed manner to prevent leakage.

In addition, to promote the circulation of the first fluid HP in the first channels before its evacuation, the first 27a and second 27b connecting portions of a plate 17, 19 may be arranged on either side of the upper plate 17 and lower 19 on a common diagonal of the plate concerned, shown in dashed lines in FIG.

In addition, in order to improve the circulation of the first fluid HP, it is also possible for the connecting portions 27a and 27b to form recesses on the inner surfaces 29 facing the upper and lower plates 17 and 19.

Furthermore in the example illustrated in Figures 1 and 2, the connecting portion 27 of the housing body 3a forms a bump relative to the surface of the housing body 3a vis-a-vis with the lower module 15a. Similarly, the connecting portion 27 of the lid 3b forms a bump relative to the surface of the lid 3b vis-à-vis the upper module 15b. And, the connecting portions 27a and 27b of the modules 15 form bumps on the outer surfaces 31 of the upper plates 17 and lower 19.

The formed bumps extend respectively to the adjacent connecting portions 27, 27a or 27b associated.

Thus, once the modules 15 assembled in the housing 3, the bumps of the connecting portions 27, 27a and 27b make it possible to define spaces 33 between one or more consecutive modules 15c and between the lower module 15a, respectively upper 15b, and the bottom of the housing body 3a, respectively the lid 3b.

These spaces 33 thus delimited form second circulation channels of the second BP fluid parallel to each other with a height which can be between 2 and 4 mm. In this example, the exchanger 1 has four second channels.

The second channels are located above and below the first channels to optimize the heat exchange between the two HP / BP fluids.

Thus, with a reduced number of modules 15, here three modules 15, one obtains several first and second channels, here three first and four second channels. canals. This limits the production costs and the size of the exchanger 1.

In addition, fins 35, or disruptive plates, can be provided in spaces 33 to increase the heat exchange area and the thermal performance.

In addition, the second channels are also parallel to the first channels so that the two HP and BP fluids flow in two parallel directions.

In this exchanger (FIGS. 1,2), the introduction orifice 11 of the second fluid BP is at the outlet orifice 13 of the first fluid HP and the discharge orifice 9 of the second fluid BP is at the level of of the introduction orifice 7 of the first fluid HP, the two fluids HP and BP circulate against the current. The countercurrent circulation makes it possible to reduce the temperature differences at the outlet of the exchanger 1 and thus to further optimize the performance of the exchanger 1.

Of course, the circulation of the two fluids HP and BP can be done in the same direction, for a co-current flow.

In order to improve the maintenance of the various modules 15, additional holding portions 37 (FIGS. 2 and 3) can be provided on the upper plates 17 and lower 19. For example, these additional portions 37 are arranged next to the connecting portions 27a and / or 27b with the same hollow characteristics on the internal surfaces 29 and bumps on the outer surfaces 31 of the upper plates 17 and lower 19 and with a larger size. reduced with respect to the connecting portions 27a and 27b. These additional holding portions 37 have an additional function in that they prohibit any displacement of the fins 35 present in the spaces 33.

Moreover, each upper plate 17 and lower 19 may have two notches respectively formed on two opposite edges 39 of the plate 17 or 19 to improve the distribution of the second LP fluid in the different second channels.

The thermal exchange performance is thus improved by keeping a relatively simple form of the upper plates 17 and lower 19 forming the modules 15.

Thus, the method of assembling an exchanger 1 as described above comprises the following steps: a solder plating is deposited on the surfaces to be joined, for example on the inner surfaces 29 of the upper 17 and lower 19 plates to form modules 15, and on the outer surfaces 31 of the upper 17 and lower 19 and the inner surface of the casing 3 to connect the modules 15 to the casing 3, alternatively the solder plating can be unitary with the aluminum strip from which the upper plates 17 and lower 19, the body 3a and the cover 3b,

alternatively upper plates 17 and lower plates 19 are introduced into casing body 3a, by placing between each upper / lower plate an interfering plate 35 or 25,

the lid 3b is fixed above the modules 15 formed by the upper plates 17 and lower 19, on the housing body 3a, by clamping the fastening tabs 5 of the housing body 3a on the cover 3b so as to exert a pressure on the modules 15, and

- The assembly formed by the housing 3 and the modules 15 is joined by brazing.

The housing 3 provides guiding and stacking of the upper plates 17 and lower 19 during this assembly process which allows a rapid assembly of the exchanger and which can be easily automated.

According to an alternative shown in FIG. 4, the exchanger 1 differs from the first embodiment previously described in that the housing 3 is made in the form of two half-housings 3 'and 3 ".

According to this second embodiment, each half-housing 3 ', 3 "respectively in contact with the lower modules 15a and 15b, comprises a connecting portion 27. The modules 15 remain identical with respect to the first embodiment previously described.

With regard to the assembly method, the two half-housings 3 ', 3 "are fixed for example by soldering at a junction 41 between the two half-housings 3', 3" to guarantee the sealing of the housing 3.

Thus, such a structure of the exchanger 1 makes it possible to limit the bulk of the exchanger 1 with upper plates 17 and lower 19 of thin thickness and reduced number of components, while guaranteeing good heat exchange performance.

In addition, the modules 15 comprising the first channels being assembled in the housing 3 with spaces 33 defining second channels both above and below these first channels, the risk of leakage are minimized.

Finally, such an exchanger 1 is particularly suitable for use within an air conditioning loop for a motor vehicle comprising a gas condenser or cooler, an expansion member, an evaporator and a compressor traversed in this order by a refrigerant. This air conditioning loop comprises a high pressure branch which starts at the compressor outlet and ends at the inlet of the expansion member, and a low pressure branch which starts at the outlet of the expansion member and ends at the inlet of the compressor. In this case, the exchanger according to the invention is used as an internal exchanger, that is to say an exchanger crossed by the high-pressure refrigerant fluid and high temperature that circulates in the first channels and crossed by the same refrigerant fluid at low pressure and low temperature flowing in the second channels. The invention also relates to the use of the exchanger in this air conditioning loop and the air conditioning loop which incorporates such an exchanger.

Claims

1. Heat exchanger between a first (HP) and a second (BP) fluids, characterized in that:

said exchanger comprises a casing (3) inside which is disposed a plurality of modules (15, 15a, 15b, 15c) respectively comprising an upper plate (17) and a lower plate (19) assembled by defining between said plates (17, 19) an inner cavity (21) forming a first circulation channel for the first fluid (HP), and in that

- At least a second circulation channel for the second fluid (BP) is delimited by the housing (3) and a space (33) between said modules.

2. Heat exchanger according to claim 1, characterized in that:

the upper (17) and lower (19) plates of a module (15, 15a, 15b, 15c) respectively have at least one connecting portion

(27a, 27b) cooperating with an adjacent adjacent connecting portion (27, 27a, 27b) of a contiguous module (15, 15a, 15b, 15c) or the housing (3), and in that

said connecting portions (27a, 27b) form bumps on the outer surfaces (31) of the upper (17) and lower (19) plates, said bumps extending respectively towards the connecting portions (27, 27a, 27b) adjacent associated.

3. Heat exchanger according to claim 2, characterized in that said connecting portions (27a, 27b) form recesses on the inner surfaces (29) vis-à-vis the upper plate (17) and lower (19) forming a module (15,15a, 15b, 15c).

4. Heat exchanger according to one of claims 2 or 3, characterized in that:

a predetermined number of connection portions (27a, 27b) are aligned with a connecting portion (27) of the housing having an introduction (7) / discharge (13) orifice of the first fluid (HP), and what

said aligned connection portions (27a, 27b) respectively have an orifice, all of said orifices communicating with each other so as to define a channel for introducing / discharging the first fluid (HP).

5. Heat exchanger according to any one of claims 2 to 4, characterized in that said plates (17, 19) respectively have two connecting portions (27a, 27b) disposed on either side of said plate (17, 19) on a common diagonal of said plate (17, 19).

6. Heat exchanger according to any one of claims 1 to 5, characterized in that said plates (17, 19) respectively have a generally parallelepipedal shape with two notches respectively formed on two opposite edges (39) of said plate (17, 19).

7. Heat exchanger according to any one of claims 1 to 6, characterized in that the housing (3) has an orifice (11) for introducing the second fluid (BP) at the discharge orifice (13). ) of the first fluid (HP), and a discharge orifice (9) of the second fluid (BP) at the introduction orifice (7) of the first fluid (HP), for a countercurrent circulation of first (HP) and second (BP) fluids.

8. Heat exchanger according to any one of claims 1 to 7, characterized in that the housing comprises a body (3a) of the housing (3) in which are stacked said modules (15, 15a, 15b, 15c), said body being closed by a cover (3b) disposed above said modules (15, 15a, 15b, 15c) and fixed to the body (3a) by means of attachment tabs (5).

9. Heat exchanger according to any one of claims 1 to 7, characterized in that the housing (3) is formed as two half-housings (3 ', 3 ") assembled.

10. Heat exchanger according to any one of the preceding claims, characterized in that it comprises fins (25,35) disposed in the inner cavity (21) which defines the first circulation channel and / or in the space (33) defined between said modules which delimits the second circulation channel.

11. Use of a heat exchanger according to any one of the preceding claims as an internal exchanger and placed within an air conditioning loop for heat exchange between a high pressure branch and a low pressure branch of said loop.

12. Air conditioning loop for a motor vehicle comprising a condenser or gas cooler, an expansion device, an evaporator and a compressor traversed in this order by the same refrigerant, said air conditioning loop comprises a high pressure branch which starts at the output of compressor and ends at the inlet of the expansion member, and a low pressure branch which starts at the outlet of the expansion member and ends at the compressor inlet characterized in that it comprises heat exchanger according to any one claims 1 to 10, said first circulation channel is placed in the high pressure branch and said second circulation channel is placed in the low pressure branch.