FR2793015A1 - Heat exchanger assembly for an automobile, utilises a cross flow configuration between the fluid supply and sump assemblies via tubular plate type heat exchange fins - Google Patents

Abstract

The heat exchanger assembly comprises of an upper supply conduit (24) and a lower return sump (22) These are connected using vertical conduits (18) that have internally a series of further conduits. The main conduits twist through 90 degrees from the supply to the sump assemblies. Located between the conduits are plate type heat exchange fins that receive a cooling air supply such that the fluid within the conduits is cooled.

Description

Brazed heat exchanger for high pressure, in particular

  The invention relates to heat exchangers, in

  especially for a motor vehicle.

  It relates more particularly to a brazed heat exchanger comprising a bundle of tubes, a manifold plate provided with openings for receiving the ends of the tubes, and a manifold box covering the manifold plate to delimit at least one internal chamber communicating with

the tubes.

  Heat exchangers of this type are already known, the various components of which are generally made of aluminum alloy and are brazed together in order to assemble them. Such heat exchangers are used in the automotive industry to exchange heat between a fluid passing through the heat exchanger and an air flow sweeping the beam. In a particular application, such a heat exchanger constitutes a condenser for a motor vehicle air conditioning installation. In this case, a refrigerant enters the gas phase in the condenser, is condensed by heat exchange with a flow

  of air, and leaves the heat exchanger in liquid phase.

  Attempts are currently being made to replace conventional refrigerants with other less polluting refrigerants, in particular with carbon dioxide, which have the disadvantage of working at high pressures which can

  reach for example 300 to 500 bars.

  This therefore results in the need to design heat exchangers capable of withstanding such high pressures, while respecting the constraints.

  of dimensions imposed by the manufacturers.

  The invention provides a solution to this problem.

  To this end, it offers a brazed heat exchanger of the type defined in the introduction, in which the manifold is produced in the form of a profile provided with at least one longitudinal partition terminated by a song suitable for being brazed against the manifold plate. so as to delimit at least two adjacent chambers, and in which the longitudinal partition comprises recesses of material in the

  regions where the ends of the tubes open.

  Thus, the manifold comprises at least one partition which is brazed to the manifold plate to define at least two adjacent chambers. This makes it possible to strengthen the structure of the assembly formed by the manifold and the manifold plate, in order to withstand high pressures, but also to reduce the overall size of this assembly in

at least one direction.

  According to another characteristic of the invention, the box

  collector comprises two lateral faces extending parallel

also at the partition (s).

  Advantageously, these side faces of the box

  collector end with a defined crenellated free edge-

  sustains or claws for holding the collecting plate

trice.

  The material recesses made in the partition (s)

  its manifold (s) are formed in line with the tubes and allow communication between these tubes and

the adjacent room (s).

  These material recesses practiced in the (or) partition

  its (s) are advantageously obtained by machining.

  According to the advantageous features of the invention, the material recesses of the partition (s) as well as the crenellated free edges of the manifold are obtained

by joint machining.

  The manifold of the invention is advantageously formed by extruding a metallic material, in particular

of an aluminum alloy.

  In a preferred embodiment of the invention, the bundle tubes are of circular section and arranged on

several rows.

  In such a case, provision is made for the tubes of at least one row to open into a chamber, while the tubes of at least one other row to open in line with a partition in the

  regions of the material recesses of said partition.

  In another embodiment of the invention, the bundle tubes are multichannel flat tubes arranged in at least one row and each having a major axis

  extending perpendicular to the partition (s).

  In this case, provision is made for the tubes to emerge in line with one or more partitions in the regions of the material recesses.

of said partition (s).

  The manifold and the manifold plate have a chosen thickness, which can reach approximately 5 mm, for their

  allow to withstand high internal pressures.

  In a preferred application of the invention, the sample

  geur is produced in the form of an air conditioning condenser

tion of motor vehicle.

  In the following description, given by way of example, we

  refers to the accompanying drawings, in which: - Figure 1 is a perspective view, partially broken away, of part of a heat exchanger according to a first embodiment of the invention;

  - Figure 2 is a side elevational view of the sample

  Figure 1 heat gor; - Figure 3 is a sectional view along line III-III of Figure 2; and - Figure 4 is a perspective view, partially broken away, of part of a heat exchanger according to a

  another embodiment of the invention.

  We first refer to Figures 1 to 3 to describe a heat exchanger according to a first embodiment

of the invention.

  This heat exchanger comprises a bundle 10 composed of a multiplicity of tubes 12 between which are arranged corrugated spacers 14 forming heat exchange fins. These tubes are here circular section tubes and are arranged in five parallel rows R1 to R5. Each of the tubes 12 comprises, in the example, a rectilinear body 16 and ends 18 offset relative to the body 16. On each side of the bundle, the ends 18 are received in receiving openings 20, which are made in

  a collecting plate 22 of generally rectangular shape.

  As can be seen in FIG. 1, the respective bodies 16 of the tubes belonging to the single rows R1 and R5 are grouped in series of five and disposed each time between two adjacent corrugated inserts 14. However, the corresponding ends 18 of the tubes are arranged aligned, but staggered, as can be seen on the

figure 1.

  The collecting plate 22 is capped by a collecting box

  trice 24 preferably produced in the form of a profile obtained by extruding a metallic material, in particular an aluminum alloy. The shape of this profile appears more particularly in Figure 3. This profile has a wall of substantially constant thickness terminated by two opposite side faces 26, substantially parallel to each other, adapted to come into abutment against respective longitudinal edges 28 of the plate manifold 22. Between the two faces 26, the wall of the manifold assumes, in a cross-sectional view, an undulating shape defining a central dome 30 comprised between two lateral domes 32, in this example (it is clear that in the hypothesis o there is only one partition, the manifold has a wavy shape defining only two side domes). Furthermore, this wall is extended inward by two longitudinal partitions 34 having respective edges 36 (Figure 1) adapted to be brazed against the collector plate, more particularly against

  a large face 38 of the latter.

  Thus, when the collector plate 22 and the collection box

  34 are brazed together, they define three

  adjacent longitudinal chambers 40 (Figures 1 and 3).

  The ends of the tubes in row R1, as well as those of the tubes in row R3 and those of the tubes in row R5

  lead respectively into the three longitudi-

  nales 40. On the other hand, the ends of the tubes of the row R2 and those of the tubes of the row R4 open out in line with the partitions 34. It is therefore expected that these partitions will include material recesses in the regions or

  open the ends 18 of the tubes of rows R2 and R4.

  So these ends can each communicate with one

  at least chambers 40, simultaneously ensuring communication

  fluid cation between neighboring chambers.

  As can be seen in Figures 1 to 3, the faces 26 have crenellated free edges 44 defining

  legs or claws 46 for holding the collecting plate

this 22.

  As can be seen more particularly in FIG. 3, the material recesses 42 of the partitions 34 and the edges

  free crenellated 44 of the manifold 24 are advantageous

  ment obtained by joint machining by means of a machining disc whose outline is represented schematically by

  a portion of a circle 48 in FIG. 3.

  It will be understood that two collector plate / collector box assemblies are thus produced having a height h which can be notably less than the width Q of the collector box (FIG. 4). Because the interior volume of this assembly is, in this example, divided into three chambers, which communicate with each other through material recesses 42, an assembly is obtained capable of withstanding

  particularly high pressures.

  The thickness of the collector plate 22 and that of the box

  collector 24 must be chosen according to the pres-

  maximum ions at which the fluid flowing through the exchanger

  heat is likely to work.

  In particular, when the heat exchanger is produced in the form of a condenser capable of being traversed by a refrigerant, of the carbon dioxide type, these pressures can reach values of the order of 300 to

Around 500 bars.

  In this case, the thickness of the respective walls of the manifold plate and the manifold box must generally be

between approximately 3 and 5 mm.

  In the embodiment of FIG. 5, the tubes 12 are flat tubes, called "multichannel", comprising a plurality of parallel internal channels 50. In the example,

  these tubes are arranged in a single row and present

  each try a large axis AA which extends perpendicularly

  to the longitudinal partitions 34 of each of the collection boxes

  trices. In the example, each of the manifolds comprises three partitions 34, which makes it possible to define four

  adjacent longitudinal chambers 40.

  Each of the collector plates 22 comprises a row of openings 20, of oblong shape which can be produced either by punching, or by machining. In all cases, there is obtained a heat exchanger capable of being traversed by a high pressure fluid and nevertheless having a reduced bulk compared to the heat exchangers.

known.

  The invention applies very particularly to heat exchangers for motor vehicles, in particular to air conditioning condensers, for which the configuration of the manifold ensures very good pressure resistance. The invention is not limited to the embodiments described above, but it extends to all the variants that

  those skilled in the art will be able to develop within the framework of the claims

cations below.

Claims (12)

Claims   1. Brazed heat exchanger, in particular for a motor vehicle, comprising a bundle (10) of tubes (12), a collecting plate (22) provided with openings (20) for receiving the ends (18) of the tubes, and a manifold box (24) covering the manifold plate (22) to delimit at least one internal chamber (40) communicating with the tubes, characterized in that the manifold box (24) is produced in the form of a profile provided with at least one longitudinal partition (34) terminated by a song (36) suitable for being brazed against the collecting plate (22) so as to delimit at least two adjacent chambers (40) and in that the longitudinal partition comprises material recesses (42) in the regions where the ends (18) of the tubes (12).   2. Heat exchanger according to claim 1, characterized in that the manifold (24) comprises two lateral faces (26) extending parallel to the (the) partition (s) (34). 3. Heat exchanger according to claim 2, characterized in that the lateral faces (26) of the manifold (24) end in a crenellated free edge (44) defining   tabs or claws (46) for holding the collecting plate trice (22).   4. Heat exchanger according to one of claims 1 to 3,   characterized in that the material recesses (42) of the   (des) partition (s) (34) are obtained by machining.   5. Heat exchanger according to claims 3 and 4,   taken in combination, characterized in that the material recesses (42) of the partition (s) (34) and the crenellated free edges (44) of the manifold (24) are obtained by joint machining.   6. Heat exchanger according to one of claims 1 to 5,   characterized in that the manifold (24) is formed by extruding a metallic material, in particular a aluminum alloy.   7. Heat exchanger according to one of claims 1 to 6,   characterized in that the bundle tubes (12) are of   circular section and arranged in several rows (R1-R5).   8. Heat exchanger according to claim 7, characterized in that the tubes (12) of at least one row (R1, R3, R5) open into a chamber (40), while the tubes (12) of at least one other row (R2, R4) lead to a partition (34) in the regions of the material recesses (42) of said partition.   9. Heat exchanger according to one of claims i to 6,   characterized in that the tubes (12) of the bundle are flat tubes comprising several channels (50) and arranged in at least one row and each having a major axis (AA) extending perpendicular to the partition (s) (34).   10. Heat exchanger according to claim 9, character-   risé in that the tubes (12) open at the right of one (of) partition (s) (34) in the regions of the material recesses   (42) of said partition (s).   11. Heat exchanger according to one of claims 1 to   10, characterized in that the manifold (24) and the manifold (22) have a chosen thickness, which can reach approximately 5 mm, to allow them to withstand high internal pressures.   12. Heat exchanger according to one of claims 1 to   11, characterized in that it is produced in the form of a   motor vehicle air conditioning condenser.