EP3519755B1 - Fluid collecting box for a heat exchanger, associated heat exchanger - Google Patents

Description

The present application relates to a fluid collecting box for a heat exchanger, as well as a heat exchanger equipped with such a device, and more particularly in applications to heating, ventilation and/or air conditioning devices.

Several types of heat exchangers exist, their roles being systematically to place a first fluid and a second fluid in proximity at different pressures and temperatures, whether for the purpose of heating the air to be blown into the the passenger compartment, or for example cooling of a motor fluid.

Some of these heat exchangers include a plurality of tubes allowing an exchange of thermal energy between a fluid flowing inside the tubes and a fluid flowing between the tubes. The tubes are connected to collector boxes whose function is respectively to distribute or collect the fluid at the ends of the tubes, depending on whether the box is upstream or downstream of the heat exchanger.

Each collector box is fluidly connected to a thermal loop via one or more openings. Thus, advantageously, the collector box makes it possible to fluidly connect all the tubes by limiting the number of connections at the loop, which in particular makes it possible to limit the risk of leaks. JP 2004 020104 discloses a collector box comprising the features of the preamble of claim 1.

The tubes are arranged so as to be parallel to each other, in order to promote heat exchange with their environment while optimizing their size. This implies that the openings present in the bottom of the collector box, intended to communicate fluidly with the tubes, are also aligned. This has the disadvantage of forcing the fluid to diffuse all along the box to ensure the supply of all the tubes. This divergent flow of the liquid in the upstream collector box imposes a turbulent flow on the fluid, leading to a loss of load as it passes through the collector box. We understand that the same phenomenon of pressure loss occurs when the fluid passes through the collector box Fluid collector box for heat exchanger, associated heat exchanger .

The present application relates to a fluid collecting box for a heat exchanger, as well as a heat exchanger equipped with such a device, and more particularly in applications to heating, ventilation and/or air conditioning devices.

Several types of heat exchangers exist, their roles being systematically to place a first fluid and a second fluid in proximity at different pressures and temperatures, whether for the purpose of heating the air to be blown into the the passenger compartment, or for example cooling of a motor fluid. The example of prior art document is [ FR 3007515A1 ].

Some of these heat exchangers include a plurality of tubes allowing an exchange of thermal energy between a fluid flowing inside the tubes and a fluid flowing between the tubes. The tubes are connected to collector boxes whose function is respectively to distribute or collect the fluid at the ends of the tubes, depending on whether the box is upstream or downstream of the heat exchanger.

Each collector box is fluidly connected to a thermal loop via one or more openings. Thus, advantageously, the collector box makes it possible to fluidly connect all the tubes by limiting the number of connections at the loop, which in particular makes it possible to limit the risk of leaks.

The tubes are arranged so as to be parallel to each other, in order to promote heat exchange with their environment while optimizing their size. This implies that the openings present in the bottom of the collector box, intended to communicate fluidly with the tubes, are also aligned. This has the disadvantage of forcing the fluid to diffuse all along the box to ensure the supply of all the tubes. This divergent flow of the liquid in the upstream collector box imposes a turbulent flow on the fluid, leading to a loss of load as it passes through the collector box. We understand that the same phenomenon of pressure loss occurs when the fluid passes through the collector box swallows, due to its converging flow towards the opening connected to the thermal loop of the heating, ventilation and/or air conditioning device.

The present invention aims to remedy these drawbacks, by proposing a fluid collecting box for a heat exchanger limiting the phenomenon of pressure loss of a fluid passing through the box.

In this context, the present invention proposes a fluid collecting box for a heat exchanger, in particular in a heating, air conditioning and/or ventilation device of a motor vehicle, comprising a receptacle delimited by at least one side wall and a wall bottom comprising several first openings substantially aligned in a direction of elongation of the box. In other words, a box according to the invention comprises a bottom and at least one side wall, preferably substantially normal to said bottom, so as to collect at said bottom, a refrigerant or heat transfer fluid according to the needs of the heat exchanger, said fluid being able to pass through the bottom wall via the first openings.

In order to temporarily store the fluid in the box, the receptacle is closed by a cover comprising at least a second opening, for receiving a supply conduit capable of being connected to the box to communicate fluidly with the receptacle and further downstream the heat exchanger.

The invention is characterized in that at least one second opening of the cover has an elongated shape substantially in the direction of elongation, and in that this second opening is arranged opposite several first openings. Thus, the entry surface of the fluid into the receptacle is extended and the distribution of this fluid is spread out, so that a substantially linear flow of this fluid is allowed through the collector box, between a second opening and several first openings. openings, and that the pressure loss phenomenon described above is thus limited at the fluid level.

By the terms “elongated shape” is meant an opening comprising at least two dimensions of different values, the largest dimension of which defines the direction of this elongated shape. Furthermore, the collector box of the invention is such that the second opening is characterized by a ratio between its largest and its smallest dimension, at least greater than 1.5; we understand that the dimensions of the second opening can be adapted according to the dimensions and the number of first openings that we wish to be opposite the second opening. By the terms "opposite", we mean a second opening revealing several first openings when we observe the interior of the collector box above the cover, this opposite arrangement allowing a linear or substantially linear flow of a fluid between said openings.

Finally, the collector box of the invention comprises a barrel arranged on the exterior face of the cover so as to surround the second opening, in order to facilitate the adjustment of a conduit to this second opening. In other words, the barrel makes it easier to mount a fluid supply conduit on the cover by acting as a guide. In this context, this barrel may have a height of between 0.8mm and 1.2mm. By the term “height” we mean a dimension of the barrel along an axis normal or substantially normal to the external face of the cover.

• la plus grande dimension de cette deuxième ouverture est supérieure à la somme de la dimension d'une première ouverture selon la direction d'allongement et de la distance séparant deux premières ouvertures successives ; ainsi, la deuxième ouverture est au moins partiellement en vis-à-vis de deux premières ouvertures quelle que soit sa position le long de la direction d'allongement, et le fluide peut s'écouler de façon linéaire entre cette deuxième ouverture et ces au moins deux premières ouvertures ;
• la deuxième ouverture est disposée en vis-à-vis d'au moins trois premières ouvertures ;
• la deuxième ouverture présente avantageusement une forme oblongue ou une forme rectangulaire, et l'on peut prévoir de façon similaire que les premières ouvertures aient également une forme allongée, oblongue ou rectangulaire, dès lors que la deuxième ouverture présente une dimension selon la direction d'allongement suffisamment grande pour couvrir une pluralité de premières ouvertures.

Depending on several characteristics, taken alone or in combination, relating to the dimensions and shape of this second opening, it can be expected that:

• the largest dimension of this second opening is greater than the sum of the dimension of a first opening in the direction of elongation and the distance separating two first successive openings; thus, the second opening is at least partially opposite two first openings whatever its position along the direction of elongation, and the fluid can flow linearly between this second opening and these at least two first openings;
• the second opening is arranged opposite at least three first openings;
• the second opening advantageously has an oblong shape or a rectangular shape, and it can be provided in a similar manner that the first openings also have an elongated, oblong or rectangular shape, since the second opening has a dimension according to the direction of elongation large enough to cover a plurality of first openings.

According to another series of characteristics, it can be provided that the free end of at least one side wall and the cover are cold deformed to secure the cover to the receptacle, and it can be provided that the cover is crimped onto the receptacle by one or more ends of one or more side walls of the receptacle.

The present invention also relates to a conduit connected to a collector box described above, comprising an orifice of shape similar to a second opening of the cover, that is to say an elongated shape, in particular oblong or rectangular.

This conduit may include a collar surrounding the wall delimiting the orifice of the conduit, in a continuous or discontinuous manner, the collar being arranged to allow the conduit to be mounted on the box, in particular by crimping the collar with at least one side wall of the box, simultaneously with the cover, and this so that the conduit communicates fluidly with the interior of the collector box via the second opening.

It can thus be provided that at least part of the collar is held on the cover by one or more free ends of a side wall of the receptacle. Preferably, in order to ensure better support, the collar is held on the cover by the free ends of two facing side walls.

According to a characteristic specific to the conduit and to the collar, the latter can have a wall thickness greater than the thickness of the wall of the conduit in the vicinity of the end which it extends substantially perpendicularly, so as to ensure better support of the conduit through the flange.

The present application also relates to a heating, ventilation and/or air conditioning device comprising at least one heat exchanger supplied with fluid by a supply conduit described above and connected to a collector box described above. For example, the first openings can be connected to tubes forming a bundle of a heat exchanger, and at least one second opening to this supply conduit of the heat exchanger.

According to a characteristic of this heating, ventilation and/or air conditioning device, it can be provided that the deformed side walls of the receptacle to fix the cover in relation to the collector box also allow the fixing of the conduit, via its flange in relation to this same collector box.
the receptacle by one or more ends of one or more side walls of the receptacle.

The present invention also relates to an assembly of a conduit and a collector box described above, comprising an orifice of shape similar to a second opening of the cover, that is to say an elongated shape, in particular oblong or rectangular.

This conduit may include a collar surrounding the wall delimiting the orifice of the conduit, in a continuous or discontinuous manner, the collar being arranged to allow the conduit to be mounted on the box, in particular by crimping the collar with at least one side wall of the box, simultaneously with the cover, and this so that the conduit communicates fluidly with the interior of the collector box via the second opening.

It can thus be provided that at least part of the collar is held on the cover by one or more free ends of a side wall of the receptacle. Preferably, in order to ensure better support, the collar is held on the cover by the free ends of two facing side walls.

According to a characteristic specific to the conduit and to the collar, the latter can have a wall thickness greater than the thickness of the wall of the conduit in the vicinity of the end which it extends substantially perpendicularly, so as to ensure better support of the conduit through the flange.

The present application also relates to a heating, ventilation and/or air conditioning device comprising at least one heat exchanger supplied with fluid by an assembly described above. For example, the first openings can be connected to tubes forming a bundle of a heat exchanger, and at least one second opening to this supply conduit of the heat exchanger.

According to a characteristic of this heating, ventilation and/or air conditioning device, it can be provided that the deformed side walls of the receptacle to fix the cover in relation to the collector box also allow the fixing of the conduit, via its flange in relation to this same collector box.

Of course, the characteristics, variants and different embodiments of the invention can be associated with each other, in various combinations, to the extent that they are not incompatible or exclusive of each other.

• la figure 1 est une vue en coupe verticale d'un mode de réalisation d'une boîte collectrice selon l'invention ;
• la figure 2 est une vue schématique de dessus de la boite collectrice illustré sur la figure 1 ;
• la figure 3 est une vue en coupe selon le plan de coupe III-III illustré sur la figure 1 ; et
• la figure 4 est une vue en perspective d'un mode de réalisation du conduit d'alimentation apte à coopérer avec la boite collectrice et visible sur les figure 1 et 2.

The characteristics of the invention mentioned above as well as others will appear more clearly on reading below the detailed description of non-limiting examples, with reference to the following appended drawings:

• there figure 1 is a vertical sectional view of one embodiment of a collector box according to the invention;
• there figure 2 is a schematic top view of the collector box illustrated on the figure 1 ;
• there Figure 3 is a sectional view according to the section plane III-III illustrated on the figure 1 ; And
• there Figure 4 is a perspective view of an embodiment of the supply conduit capable of cooperating with the collector box and visible on the figure 1 And 2 .

A collector box 1 according to the invention comprises at least one receptacle 2 delimited by a bottom wall 4 and two side walls 6 extending substantially perpendicularly two opposite edges of this bottom wall, so as to form a substantially U-shaped cavity. In order to contain a fluid in the collecting box, the latter also comprises a cover 8 brought to be arranged substantially parallel to the bottom wall and which will be described in more detail below, and two end walls 10 which are extend transversely to the bottom and side walls. The collector box is connected, within a thermal loop, in a heating, ventilation and/or air conditioning device, via connection pipes made integral with connection elements carried by this box, and in particular via a conduit. supply 12 of a first fluid as illustrated in the Figure 4 and which will be detailed in more detail below.

As part of the application of the collector box to a heat exchanger, a first fluid is brought via the supply conduit 12 upstream of the box collector, to be poured into the receptacle 2 which forms a distribution chamber for this fluid. The fluid is then distributed between different exchange tubes 14 allowing, in a heat exchange chamber not shown, to facilitate the heat exchange with a second fluid circulating along these exchange tubes. We understand that in this context, the receptacle is made from materials impervious to the fluid that it must accommodate. Likewise, the thicknesses of the bottom and side walls are chosen so as to resist the pressure of the fluid present in the box.

The collector box 1 may include a plurality of receptacles 2 aligned in the direction of extension of the box, corresponding to the axis AA visible on the figures 2 and 3 , each receptacle 2 being closed transversely by end walls 16, which can take the form of a transverse closing wall of the box for the receptacles arranged at the ends of this box, or the shape of a transverse separation wall (as visible on the figure 1 ) between two consecutive receptacles.

The cover 8 closes the receptacle 2 at the level of the free ends of the side walls 6, that is to say the ends opposite the bottom wall 4. The cover can be made from the same materials as the side walls and the bottom wall of the box, such as for example from metal or a polymer-based compound.

The cover 8 is fixed to the side walls 6 by a known technique of assembling sheets by cold deformation, namely here by crimping the side walls with the cover. In order to facilitate these operations, the cover can rest on lugs 18 arranged projecting from the side walls towards the inside of the receptacle. According to the invention, it should be noted that the cold deformation operation making it possible to secure the cover 8 to the side walls 6 also allows the fixing of the supply conduit 12 of the first fluid to the collector box 1, such that will be detailed below.

The collector box has a plurality of openings to allow the fixing of tubes allowing the circulation of fluid through the receptacle(s) 2. These openings consist of, on the one hand, first openings 20 passing through the bottom wall 4 of the receptacle 2 to allow a fluid to exit the collector box and a second opening 22 made in the cover to allow the passage of a fluid from the outside to the inside of the box, this second opening 22 having according to the invention a specific shape, here oblong, in order to be opposite a plurality of first openings 20, which here are of circular shape.

In particular, the elongated shape of the second opening will be characterized by a ratio, between its largest and its smallest dimension, at least greater than 1.5. As has just been clarified, this makes it possible to arrange a second opening 22, through which the first fluid enters the receptacle, facing a plurality of first openings 20, through which the first fluid leaves the receptacle. The flow of the first fluid through the receptacle is thus subject to fewer disturbances and suffers fewer pressure losses.

The first and second openings are aligned along the same axis AA visible on the Figure 3 and the second oblong-shaped opening 22 is arranged so that its largest dimension, or length, coincides with the axis AA. Furthermore, the width of the second opening 22 is equal to or greater than the diameter of the first openings 20, or the diameter of the largest of the first openings if these have different dimensions, so that the entire plurality of first openings openings 20 facing the second opening 22 are directly accessible from this second opening 22. In other words, the plurality of first openings 20 facing the second opening 22, here in the number of three (visible on the Figure 4 ), is inscribed in a volume extending from the cover to the bottom wall, perpendicular to the cover and/or to the bottom wall, and having the section of the oblong shape of the second opening. It is understood that the dimensions of the second opening 22 depend on the dimensions of the first openings 20 and their spacing. According to the present example, the first openings 20 have a diameter of 5 mm and are spaced apart from each other, along the axis AA, by 3 mm, while the length and width of the second opening 22 are respectively equal to or greater at 25mm and 10mm.

In this context of the invention, where the elongated shape of the second opening 22 makes it possible to cover a plurality of first openings 20, it is understood that the first fluid entering the distribution chamber formed by the collector box can be evacuated via the first openings 20 with a predominantly linear flow, that is to say with a minimum of disturbance of the flow (the indirect flow being represented by the two curved arrows Fi at the ends of the direct flow Fi visible on the figure 1 ).

We understand that this characteristic can be obtained with a plurality of shapes, such as oblong, rectangular shapes, since the dimension in the direction of elongation of the box allows the covering of several first openings by the second opening.

In a particular embodiment of the invention, the cover 8 comprises on its upper face, facing away from the receptacle, a barrel 24 positioned around the second opening 22. It is therefore understood that the barrel also has a shape elongated in the direction of elongation AA of the collector box, and here an oblong shape, as is particularly visible on the Figure 3 .

We will now describe the supply conduit 12 connected to a collector box 1 described above, particular in that it has at its proximal end 26, that is to say the end brought to be made integral with the collector box, an opening similar in shape to a second opening of the cover, that is to say of elongated shape, here oblong.

Furthermore, this conduit has, still at this proximal end 26, a collar 28, extending substantially perpendicularly from the wall of the conduit at this proximal end, and surrounding the opening of the conduit. This collar, here continuous, but which could be discontinuous without departing from the context of the invention, is arranged to allow the crimping of the conduit on the cover during the operation of crimping the cover on the collector box. Thus fixed, the conduit communicates fluidly with the distribution chamber via the second opening 22 of the collector box.

We have shown schematically on the Figure 3 the covering of the collar 28 by two folded edges 30, so as to trap it between the upper face of the cover and the folded edges 30 of the side walls 6 of the box.

This cold material deformation operation to lock the collar 28 and therefore the supply conduit 12 in position relative to the collector box 1 is carried out when the conduit 12 is perfectly in place facing the second opening 22. The barrel 24 makes it possible to align the opening provided at the proximal end 26 of the conduit 12 with the second opening 22, by fitting, or at least by guiding the conduit around the barrel.

It can be provided that the thickness of the collar 28 is greater than the thickness of the conduit, at least in the proximal end zone which the collar extends substantially perpendicularly. We understand that this makes it possible to ensure better retention of the conduit on the collector box via the extra thickness of the collar, without the entire conduit being oversized, which avoids additional cost and excess weight.

It could be envisaged that only one free end of a side wall is deformed to cover the flange when the supply conduit is in position, but in the preferred embodiment, in order to ensure better support, the flange is held on the cover by the ends of two facing side walls.

The preceding description clearly explains how the invention makes it possible to achieve the objectives it has set for itself and in particular to propose a collector box in a ventilation, heating and/or air conditioning device which is particularly easy to assemble and which allows distribution of the fluid through the collector box minimizing pressure losses. It is particularly interesting according to the invention that the second opening made on the cover of the collector, to cooperate with a supply pipe and facilitate the passage of the fluid through a distribution chamber of the collector box towards a plurality of tubes, or of specific dimensions to be opposite a plurality of these tubes, in order to increase the linearity of flow of this fluid and to reduce the pressure losses which would result from a linear flow.

Of course, various modifications can be made by those skilled in the art to the structures of the collector box and the associated conduit, since it is possible to ensure a linear flow of the fluid by placing a plurality of tubes for evacuating a fluid downstream of a distribution chamber with a conduit for supplying this fluid upstream of the distribution chamber.

Claims (12)

1. Fluid header tank (1) for a heat exchanger, comprising a receptacle (2) delimited by at least one side wall (6) and a bottom wall (4) having multiple first openings (20) substantially aligned along a direction of elongation of the tank (A-A), the receptacle being closed by a cover (8) having at least a second opening (22) for receiving a supply duct opposite multiple first openings (20), wherein said second opening (22) has an elongate shape having a larger dimension along the direction of elongation of the tank (A-A) and said second opening having a ratio between its largest and its smallest dimension at least greater than 1.5, characterized in that it has a sleeve (24) which protrudes from the outer face of the cover (8) to surround said second opening (26) .
2. Header tank according to Claim 1, characterized in that the largest dimension of said second opening (22) is greater than the distance separating two successive first openings (20) arranged opposite said second opening.
3. Header tank according to the preceding claim, characterized in that said second opening (22) is placed opposite at least three first openings (20).
4. Header tank according to one of the preceding claims, characterized in that said second opening (22) has an oblong shape.
5. Header tank according to one of the preceding claims, characterized in that the free end of at least one side wall (6) and the cover (8) are deformed in the cold state in order to fix the cover to the receptacle (2) .
6. Header tank according to the preceding claim, characterized in that the cover (8) is crimped on the receptacle (2) by way of one or more ends of one or more side walls (6) of the receptacle.
7. Assembly of a duct (12) and a header tank (1) according to one of the preceding claims, characterized in that it comprises, at a proximal end (26), an orifice with an elongate shape similar to the shape of said second opening (22) formed in the cover (8).
8. Assembly according to Claim 7, characterized in that it comprises a flange (28) which at least partially surrounds said orifice and is designed to make it possible to mount said duct on the cover (8) of the header tank.
9. Assembly according to the preceding claim, characterized in that at least part of the flange (28) is held on the cover (8) by way of one or more ends of a side wall (6) of the receptacle (2) that is subjected to cold deformation.
10. Supply assembly according to Claim 8 or 9, characterized in that the flange (28) has a wall thickness greater than the thickness of the wall of the duct (12) in the vicinity of the proximal end (26) that it extends.
11. Heating, ventilation and/or air-conditioning device comprising at least one assembly according to one of Claims 7 to 10 connected to a header tank (1) according to one of Claims 1 to 6.
12. Device according to the preceding claim, characterized in that the deformed side walls (6) of the receptacle (2) fix both the cover (8) and the flange (28) of the duct (12) relative to the header tank.

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