EP1546627B1 - Plate heat exchanger, in particular for motor vehicles - Google Patents

Description

The invention relates to heat exchangers according to the preamble of claim 1, in particular for motor vehicles.

Such an exchanger is known, for example, from the document US 5,180,004 . Heat exchangers of this type usually comprise a bundle of tubes and vanes of which at least one end is connected to a header to allow the circulation of a first fluid which exchanges heat with a second fluid sweeping the beam of the heat exchanger.

Such a heat exchanger may constitute, for example, an engine cooling radiator or a heating radiator of the passenger compartment. In this case, the heat exchanger is usually traversed by the engine coolant.

The heat exchanger can also constitute an evaporator or a condenser of an air conditioning circuit. In this case, the fluid flowing through the heat exchanger is a coolant.

Heat exchangers are also known, known as "plate heat exchangers", which comprise a multiplicity of stacked plates, arranged in pairs facing each other, and arranged to define a multiplicity of chambers for the circulation of heat exchangers. a first fluid, this fluid exchanging heat with a second fluid flowing outside the plates.

Heat-exchanging corrugated inserts are also usually provided which are each placed between a plate of one pair and a plate of another adjacent pair.

These plate heat exchangers are rather used in air conditioning circuits, for example as evaporators, or for cooling an oil, in particular the engine lubricating oil, the gearbox oil, etc.

These heat exchangers are always traversed by a flow of air that is cooled or heated according to the applications. However, all these known heat exchangers do not make it possible to optimize the heat exchange between the first fluid and the second fluid.

The invention proposes for this purpose a heat exchanger according to claim 1.

Thus, in each of the chambers, the first fluid flows countercurrently with respect to the second fluid that circulates outside the plates. This results in a better heat exchange compared to known heat exchangers, whether they are tube bundle heat exchangers or plate heat exchangers.

Advantageously, the inlet and the outlet of a plate are formed by openings arranged in the plane of the plate and are each bordered by a collar to allow connection to the inlet and the outlet of an adjacent plate forming part of the plate. an adjacent room.

In this way, it is possible to communicate, step by step, on the one hand the fluid inputs of the plates, and on the other hand the fluid outlets of the plates.

As a result, the first fluid feeds the respective inputs of the plates, circulates in the chambers against the current and leaves the plates by their respective outlets.

According to another characteristic of the invention, each plate comprises deflectors formed projecting from the lower side of the plate which faces the chamber, to promote the flow of the first fluid against the current.

It is advantageous that the respective deflectors of two plates facing each other which delimit a chamber are in mutual contact. This makes it possible to define countercurrent circulation channels for the first fluid.

The baffles can be made in different ways.

These deflectors may comprise generally straight deflectors favoring a direct flow against the current of the first fluid from the inlet to the outlet.

They may also comprise deflectors favoring a U-shaped flow of the first fluid with a first path extending from the entrance and extending in a transverse direction, a second counter-current path and a third path extending in the transverse direction and leading to to the output. In the first and third paths, the first fluid flows in the transverse direction, that is to say in a direction generally perpendicular to the flow of the second fluid, which does not affect the heat transfer. On the other hand, in the second path, or intermediate path, the circulation is carried out against the current. Therefore, here too, the heat exchange is optimized.

In an alternative embodiment, each plate comprises a relief in the form of a clean edge coming into contact with a homologous relief of a plate facing to separate the chamber in two volumes.

According to the invention, each plate comprises a first input / output pair formed of an input and an output and disposed near a first end of the plate and a second input / output pair formed of an input and a an outlet and disposed near a second end of the plate.

This makes it possible to define two traffic paths in the same chamber: a first path between a first input and a first output, and a second path between a second input and a second output.

In this embodiment, each plate is preferably of generally rectangular shape and has two long sides and two short sides. The first input / output pair is then disposed near a first small side, while the second input / output pair is disposed near a second small side.

The heat exchanger of the invention comprises a manifold arranged to be connected to a plate, said end plate, located at the end of the stack, and this plate has a main inlet arranged to direct the first fluid towards the ( the) inlet (s) of the end plate and a main outlet arranged to collect the first fluid from the (the) outlet (s) of the end plate.

When each plate includes a first input / output pair, as previously mentioned, the manifold is arranged to include an elongated input compartment which communicates with the main entrance and with both entrances the end plate, and an elongate outlet compartment that communicates with the main outlet and with both end plate outlets.

It is also advantageous that the device comprises a fluid distributor interposed between the header and the end plate and arranged, firstly to direct the first fluid from the main inlet to the inlet (s) of the end plate, and secondly from the outlet (s) of the end plate to the main outlet.

The plates can be generally flat. However, it is advantageous to provide flow disturbers formed projecting inwardly of the chambers.

According to another characteristic of the invention, the heat exchanger comprises corrugated dividers, each disposed between two plates belonging to two adjacent chambers.

The heat exchanger of the invention is advantageously made from metal components, preferably based on aluminum, assembled together by soldering in a single operation.

The invention applies in particular to a heat exchanger in which the first fluid is a heat transfer fluid, and wherein the second fluid is air.

- la Figure 1

est une vue en perspective très schématique d'un échangeur de chaleur à plaques selon l'invention illustrant le principe de circulation à contre-courant des deux fluide ;

- la Figure 2

est une vue de côté d'un échangeur de chaleur à plaques selon l'invention ;

- la Figure 3

est une vue en plan d'une plaque propre à faire partie de l'échangeur de chaleur de la Figure 2 ;

- la Figure 4

est une vue analogue à la Figure 3 montrant la circulation en U du premier fluide dans une chambre ;

- la Figure 5

est un détail de l'assemblage mutuel de deux plaques ;

- la Figure 6

est une vue de dessus d'une boîte collectrice de l'échangeur ; et

- la Figure 7

est une vue de dessus d'un répartiteur de l'échangeur de chaleur.

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

- Figure 1

is a schematic perspective view of a plate heat exchanger according to the invention illustrating the principle of countercurrent circulation of the two fluid;

- Figure 2

is a side view of a heat exchanger at plates according to the invention;

- Figure 3

is a plan view of a clean plate to be part of the heat exchanger of the Figure 2 ;

- Figure 4

is a view similar to the Figure 3 showing the U-shaped circulation of the first fluid in a chamber;

- Figure 5

is a detail of the mutual assembly of two plates;

- Figure 6

is a top view of a manifold of the exchanger; and

- Figure 7

is a top view of a distributor of the heat exchanger.

We first refer to the Figure 1 which shows, schematically and in perspective, a heat exchanger 10, the plate type according to the invention. This heat exchanger comprises a series of stacked plates 12, arranged in pairs facing each other. Each of the pairs defines a chamber for the circulation of a first fluid that circulates in each of the plates in generally parallel directions from left to right (in the figure), as shown by the arrows F1. This first fluid exchanges heat with a second fluid which circulates outside the plates and against the current, as shown by the arrow F2, that is from right to left in the drawing of the Figure 1 .

The first fluid is admitted into the heat exchanger through an inlet 14 and out of an outlet 16 after exchanging heat with the second fluid. The first fluid is advantageously a heat transfer fluid, while the second fluid is advantageously a flow of air.

We now refer to the Figure 2 which shows, in side view, a heat exchanger made according to the invention. This heat exchanger comprises a stack formed of a multiplicity of plates 12 arranged in pairs, the two 12 of the same pair being generally identical and arranged vis-à-vis to delimit between them a chamber 18 ( Figure 5 ) for the circulation of the first fluid.

The plates communicate with each other by respective collars or tips to allow the entry and exit of the fluid, as will be seen later. Between a plate 12 delimiting a first chamber and a plate 12 delimiting another adjacent chamber, is located, each time, a corrugated spacer 20 ( Figures 1 and 5 ) forming a heat exchange fin. At a first end, the exchanger comprises a manifold 22 connected to a first end plate 12A. At its other end, the exchanger comprises an end plate 12B which is capped by a closure plate 24.

We now refer to the Figure 3 to describe in more detail the structure of a plate 12, it being understood that the other plates are identical. The plate 12 shown on the Figure 3 is obtained by stamping a metal sheet, preferably aluminum or aluminum-based alloy. It comprises a bottom 26 of generally rectangular shape, surrounded by a raised edge 28. The plate comprises two large opposite sides 30 and 32 and two small opposite sides 34 and 36.

Through the plate 12, a first input / output torque is arranged near the small side 34, comprising a fluid inlet 38 and a fluid outlet 40. The inlet 38 is located near the long side 30 and the outlet 40 near the long side 32. Each of these inputs or outputs is formed by an opening of generally circular shape which is bordered by a collar. The inlet 38 has a collar 42 and the outlet 40 a collar 44, these two collars protruding from the outer side of the plates, that is to say the side opposite the chamber. These collars 42 and 44 are intended to be connected to similar collars of an adjacent plate. We distinguish on the Figure 2 and on the detail of the Figure 5 the way the collars 44 are joined together. It is the same for snares 42. Furthermore, near the small side 36, is formed another input / output pair comprising a fluid inlet 46 and a fluid outlet 48. The inlet 46 is located near the long side 30 and the outlet 48 near the long side 32. The inlet 46 and the outlet 48 are also formed by circular openings lined respectively by flanges 50 and 52.

We can also see on the Figure 2 the way the collars 52 are joined together. It is the same for snares 50.

In the plate 42, are formed a number of reliefs promoting the circulation of the first fluid in the chamber defined by two plates vis-à-vis. Thus, each plate comprises two reliefs 54 and 56 starting respectively from the inlet 38 and the outlet 40 and extending in a direction generally parallel to the long sides 30 and 32 of the plate. Similarly, from the inlet 46 and the outlet 48 extend two other similar reliefs 58 and 60 which extend parallel to the long sides 30 and 32.

In addition, various reliefs are formed in a direction parallel to the short sides 34 and 36. On the side of the inlet 38 and the outlet 40, there is successively a first relief 62 and a second relief 64 spaced apart from one of the other and both parallel to the short side 34. On the side of the entrance 46 and the exit 48, there are two other similar reliefs, namely a relief 66 and a relief 68, also parallel to the small side 36. These reliefs 66 and 68 correspond to the symmetrical replicas of the reliefs 62 and 64. In fact, the plate admits a symmetry with respect to a line L. In the central region of the plate, there is another relief 70 of shorter length.

It should be noted that the aforementioned reliefs come into contact with homologous reliefs of the plate vis-à-vis. These reliefs are deflectors that channel the flow of the first fluid in the chamber thus formed.

Alternatively, the relief 70 may have an edge shape and extend over the entire width of the plate. The relief 70 comes. then in contact with a homologous relief 70 of the plate opposite, thus separating the chamber 18 in two volumes.

We now refer to the Figure 4 to better describe the flow of fluid in a chamber, as shown on one of the plates of the chamber. The chamber is simultaneously fed first fluid through the inlet 38 (top in the drawing) and the inlet 46 (bottom in the drawing). The fluid circulates in the chambers by a substantially U-shaped circulation. A first circulation path represented by an arrow F3 comprises a first transverse path along the relief 54, a counter-current path along the relief 62, then another path transverse to gain the exit 40. Another U-shaped path (arrows F4) is made between the edge of the long side 30 of the plate and the relief 54, then between the reliefs 68 and 70, and finally between the relief 56 and the In all these paths, there is a counter-current intermediate path and two transverse extreme paths, that is to say parallel to the long sides of the plate, which have no influence on the path. thermal performance.

There are symmetrical paths for the fluid which enters through the inlet 46 and escapes through the outlet 48. Thanks to the presence of the aforementioned reliefs, each time a circulation against the current is promoted, which improves the exchange between the first fluid F1 and the second fluid F2, as mentioned above with reference to the Figure 1 .

The first fluid is fed simultaneously to the inputs 38 and the inputs 46 of the different plates and it is discharged from the outlets 40 and outputs 48 of the different plates which communicate with each other.

The manifold 22 will be described now in more detail with reference to the Figure 6 . It comprises a stamped plate of generally rectangular shape surrounded by an edge 72 capable of being joined by brazing along the edge 28 of the first plate 12A, with the interposition of a splitter 74 (shown in broken lines on the Figure 2 ) and which will be described later with reference to the Figure 7 . The manifold is drawn to form two elongate bosses 76 and 78 which delimit two respective compartments. The boss 76 comprises, in its center, a main inlet 80 for the first fluid, while the boss 78 comprises at its center a main outlet 82 for the first fluid.

Dispatcher 74 ( Figure 7 ) comprises a stamped rectangular plate having, at one end, an inlet 84 and an outlet 86 adapted respectively to correspond with the inlet 38 and the outlet 40 of the end plate 12A. It comprises, at its other end, an inlet 88 and an outlet 90 adapted to correspond respectively with the inlet 46 and the outlet 48 of the first end plate 14A. The splitter 74 is stamped and delimits a double ramp. A first ramp 92 directs the first fluid from the main inlet 80 simultaneously to the inputs 84 and 88 of the distributor and thus to the inputs 38 and 46 of the different plates. The other ramp 94 associated with the boss 78 makes it possible to direct the fluid coming respectively from the outputs 86 and 90 of the distributor, and therefore the outputs 40 and 48 of the plates, towards the main output 82.

Thus, the fluid is fed simultaneously into the inlets 38 and 46 of the plates, circulates countercurrently in the different chambers and reaches the outlets 40 and 48 of the plates and is then discharged through the main outlet 82. This arrangement always favors an exchange. countercurrent heat between the first fluid and the second fluid.

The plates may include, where appropriate, flow disturbers, as schematically shown by the reference 96 on the Figure 3 . In the drawing only three flow disruptors 96 are shown for simplification purposes, but in fact they are more numerous and distributed over the entire extent of the plate. These are bosses projecting inwardly of the chamber which disturb the flow of the first fluid and optimize the heat exchange with the second fluid. These disrupters can be made of different shapes.

The invention finds a preferential application to heat exchangers for motor vehicles.

They may constitute radiators traversed by a heat transfer fluid, for example the engine cooling fluid, or a heat exchanger traversed by a refrigerant fluid.

Of course, the invention is not limited to the embodiment described above by way of example. In particular, it is possible to design also plates each having a single input and a single output.

Claims (14)

1. Heat exchanger comprising a multitude of stacked plates arranged in pairs and facing one another and arranged to define a multitude of chambers for the circulation of a first fluid exchanging heat with a second fluid flowing on the outside of the plates, each plate (12) comprises at least one fluid inlet (38, 46) and a fluid outlet (40, 48) for the first fluid (F1), these respectively communicating with homologous inlets and outlets of the other plates and being arranged in such a way that the first fluid is forced to circulate in each chamber (18) from the inlet towards the outlet in a countercurrent direction with respect to the direction in which the second fluid (F2) circulates, each plate (12) comprises a first inlet/outlet pair formed of an inlet (38) and of an outlet (40) and arranged near a first end (34) of the plate and a second inlet/outlet pair formed of an inlet (46) and of an outlet (48) and arranged near a second end (36) of the plate, characterized in that it comprises a header tank (22) arranged to be connected to a plate (12A) referred to as the end plate, situated at an end of a stack, and in that the header tank (22) comprises a main inlet (80) arranged to direct the first fluid towards the inlets (38, 46) of the end plate and a main outlet (82) arranged to collect the first fluid coming from the outlets (40, 48) of the end plate.
2. Heat exchanger according to Claim 1, characterized in that the fluid inlet (38, 46) and the fluid outlet (40, 48) of a plate (12) are formed by openings made in the plane of the plate and are each bordered by a collar (42, 50, 44, 52) so as to allow this inlet and this outlet to be connected to the inlet and to the outlet of an adjacent plate that forms part of an adjacent chamber (18).
3. Heat exchanger according to one of Claims 1 and 2, characterized in that each plate (12) comprises deflectors (54, 56, 58, 60, 62, 64, 66, 68, 70) formed as projections on the interior side of the plate which faces towards the chamber (18), in order to encourage the countercurrent flow of the first fluid.
4. Heat exchanger according to Claim 3, characterized in that the respective deflectors (54, 56, 58, 60, 62, 64, 66, 68, 70) of two plates (12) that face one another and that delimit a chamber (18) are in mutual contact.
5. Heat exchanger according to one of Claims 3 and 4, characterized in that the deflectors comprise generally rectilinear deflectors (62, 64, 66, 68) encouraging direct countercurrent flow of the first fluid from the inlet towards the outlet.
6. Heat exchanger according to one of Claims 3 to 5, characterized in that the deflectors comprise deflectors (54, 56, 58, 60) that encourage the first fluid to flow in a U-shape with a first path leaving from the inlet (38, 46), a countercurrent second path and a third path extending in a transverse direction and leading to the outlet (40, 48).
7. Heat exchanger according to one of Claims 1 to 6, characterized in that each plate (12) has a ridged relief (70) able to come into contact with a homologous relief (70) of a plate facing it in order to divide the chamber (18) into two volumes.
8. Heat exchanger according to any one of the preceding claims, characterized in that each plate (12) is of rectangular overall shape and comprises two long sides (30, 32) and two short sides (34, 36), and in that the first inlet (38)/outlet (40) pair is arranged near a first short side (34), while the second inlet (46)/outlet (48) pair is arranged near a second short side (36).
9. Heat exchanger according to Claims 8, characterized in that the header tank (22) comprises an inlet compartment (76) of elongate shape which communicates with the main inlet (80) and with the two inlets (38, 46) of the end plate, and an outlet compartment (78) of elongate shape which communicates with the main outlet (82) and with the two outlets (40, 48) of the end plate.
10. Heat exchanger according to Claim 10, characterized in that it comprises a fluid distributor (74) interposed between the header tank (22) and the end plate (12A) and designed, on the one hand, to direct the first fluid (F1) from the main inlet (80) towards the inlets (38, 46) of the end plate and, on the other hand, from the outlets (40, 48) of the end plate (12A) towards the main outlet (82).
11. Heat exchanger according to one of Claims 1 to 10, characterized in that the plates are fitted with flow perturbators (96) formed as projections towards the inside of the chambers (18).
12. Heat exchanger according to one of Claims 1 to 11, characterized in that it comprises corrugated inserts (20) each arranged between two plates belonging to two adjacent chambers (18).
13. Heat exchanger according to one of Claims 1 to 12, characterized in that it is made of metal components, advantageously based of aluminium, assembled with one another by brazing in a single operation.
14. Heat exchanger according to one of Claims 1 to 13, characterized in that the first fluid (F1) is a coolant, while the second fluid (F2) is air.

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