FR2947045A1 - HEAT EXCHANGER BLOCK, ESPECIALLY FOR AIR CONDITIONING CONDENSER - Google Patents

Abstract

A heat exchanger block comprises a beam (12) formed by an alternating stack of flat tubes (14) for the circulation of a first fluid (F) and disrupters (16) for the circulation of a second fluid ( F) between the tubes, flat ends (18) in which are received the respective ends of the tubes (14), these ends (18) being each formed by the assembly vis-à-vis two shells (20) having a bottom (22) in which is arranged at least one communication opening (24), to form two series of end pieces (18) at the respective ends of the bundle, the end pieces (18) of each series communicating with each other by their openings; communication (24) for forming an inlet manifold (26) and an outlet manifold (28) for the first fluid (F); and a housing (30) enveloping the beam (12), said housing being provided with an inlet (48) and an outlet (50) for the first fluid (F) and an inlet (52) and an output (54) for the second fluid (F). Application in particular to air conditioning condensers.

Description

The invention relates to heat exchangers, in particular for motor vehicles.

It relates more particularly to a heat exchanger block comprising an alternating stack of channels for the circulation of a first fluid and channels for the circulation of a second fluid, and a heat exchanger comprising at least one such block. .

Such heat exchangers can be used, for example, as air conditioning condensers for motor vehicles. The first fluid can then be constituted by a refrigerant, with or without phase change, and the second fluid by a cooling fluid such as glycol water.

Heat exchangers of this type are often made by a technology of stacked plates having corrugations for disturbing the flow of the two fluids, as in document FR 2 846 733. These plates generally have raised peripheral edges which are assembled together. sealingly to delimit between the plates of the first and second flow channels for the respective fluids. The disadvantage of such plates is that they offer little modularity as regards the size and the adaptation of the passage sections according to the properties of the fluids. Moreover, problems of soldering, and thus of sealing and resistance to pressure, may appear at the level of the fluid passages. Patent FR 2 834 336 teaches a heat exchanger, in particular a condenser, composed of tubes whose ends are received in end pieces, also called staples, which communicate with each other via lateral openings. However, this solution requires drilling the tubes to ensure the flow of fluid.

Also known from US Pat. No. 6,540,015 is a condenser using tubes for the circulation of a refrigerant and other tubes for the circulation of a cooling fluid. These latter tubes may each consist of at least two plates.

This solution also has a number of disadvantages, including a complexity of construction. Indeed, the use of a fluid tube involves a lot of material engaged to close the flow of fluids.

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

It proposes for this purpose a heat exchanger block of the type defined in the introduction, which comprises a beam formed by an alternating stack of flat tubes for the circulation of the first fluid and disruptive for the circulation of the second fluid between the tubes; flat ends in which are received the respective ends of the tubes, these ends being each formed by the assembly vis-à-vis two shells having a bottom in which is arranged at least one communication opening, to form two series of ferrules at the respective ends of the bundle, the tips of each series communicating with each other through their communication openings to form an inlet manifold and an outlet manifold for the first fluid; and a housing enclosing the bundle, said housing being provided with an inlet and an outlet for the first fluid and an inlet and an outlet for the second fluid.

Thus, the exchanger of the invention comprises a beam formed by an alternating stack of tubes and disrupters for defining respectively the circulation channels of the first fluid and the second fluid. The end pieces placed at the ends of the tubes make it possible to define, on the one hand, an inlet manifold box at one end of the bundle and, on the other hand, an outlet manifold box at another end of the bundle. These inlet and outlet manifolds are for the first fluid. The flat tips communicate with each other through respective communication apertures that are aligned with each other for each series of tips, without the need for openings through the tubes of the bundle, which simplifies manufacture.

The beam is housed in a housing that contains the second fluid and allows the second fluid to flow between the flat tubes of the beam to achieve a heat exchange between the two fluids.

The entire heat exchanger block can be made from aluminum-based components, suitably plated with a solder alloy, to allow assembly of the block in a single brazing operation.

Such a heat exchanger block is particularly suitable for producing an air conditioning condenser, in particular for motor vehicles, in which the first fluid is a refrigerant and the second fluid is a cooling fluid.

The refrigerant may be a fluid with or without a phase change, such as a fluorinated fluid, or a fluid operating in supercritical mode, such as CO2. The second fluid is advantageously water, that is to say usually water added with antifreeze. It may therefore be a motor vehicle engine coolant, or a secondary cooling loop, called a low temperature loop.

In another aspect, the invention relates to a heat exchanger comprising at least one heat exchanger block as defined above. In an advantageous embodiment, this heat exchanger is in the form of a condenser, in which the first fluid is a refrigerant and the second fluid is a cooling fluid.

In this particular application, the heat exchanger advantageously comprises two heat exchanger blocks, namely a condensation block and a subcooling block, and a bottle arranged between them, so that the first fluid, that is to say the refrigerant, passes successively through the condensation block, the bottle and the subcooling block.

In the following detailed description, given by way of example only, reference is made to the accompanying drawings, in which:

- Figure 1 is a schematic front view, with partial cutaway, of a heat exchanger block according to the invention - Figure 2 is a perspective view of a shell for the production of a tip; FIG. 3 is a perspective view of a condenser comprising a condensation block and a subcooling block, both made according to the teachings of the invention, as well as a bottle interposed between the two blocks;

- Figure 4 is a longitudinal sectional view of the heat exchanger of Figure 3; Fig. 5 is a cross-sectional view of the heat exchanger of Fig. 3;

FIG. 6 is a perspective view of a heat exchanger block according to the invention associated with an end cheek; and

FIG. 7 is a perspective view of a heat exchanger comprising a housing having two end flanges 20 according to FIG. 6.

Reference is first made to FIG. 1 which shows a heat exchanger block 10, which comprises a beam 12 formed by an alternating stack of flat tubes 14 for the circulation of a first fluid F1 and disrupters 16 , made in the form of corrugated inserts, for the circulation of a second fluid F2 between the tubes 14. The flat tubes are advantageously multi-channel tubes which can be made for example by extrusion or by folding a metal strip housing an insert or disruptor, as well known in this technique.

The respective ends of the tubes are received in flat tips 18 each formed by the assembly vis-à-vis two shells 20 which each have a bottom 22 in which is arranged at least one communication opening 24. In the For example, all the shells are identical to each other and they are grouped in pairs by rotating each time their concavities toward each other to define a fluid chamber into which a tube end opens.

The tubes 14 are, for example, flat tubes arranged parallel to each other and having the same length. Thus two sets of tips are formed at the respective ends of the bundle, the tips of each series being aligned with each other.

In the example, the tips located on the left side of the figure together form an inlet manifold 26 for the fluid F1, while the ends located on the right side of the figure form an outlet manifold 28 for the fluid F1 . A heat exchanger block is thus produced in which the first fluid F1 circulates in a single pass, that is to say with an I-circulation, from the inlet manifold 26 to the outlet manifold. .

The beam is housed in a housing 30, in the example of generally parallelepipedal shape, which comprises a casing 32 with a bottom wall 34 to which are attached two opposite side walls 36 and two other opposite side walls 38 so as to jointly delimit an open face 40 of generally rectangular shape for receiving a cover 42 to close the open face 40. The cover 42 has a bottom 44 of generally rectangular shape surrounded by a flange 46 intended to be applied against the side walls 36 and 38 of the casing near their free ends to form a tight assembly. The bottom 44 is provided with an inlet opening 48 aligned with the openings 24 of the end pieces 18 of the inlet manifold 26 and an outlet opening 50 aligned with the openings 24 of the end pieces 18 of the manifold. The apertures 48 and 50 respectively constitute an inlet and an outlet for the fluid F1, which allows this fluid to enter the housing through the inlet opening 48, then to circulate in the tubes of the bundle and exit through the exit aperture 50, as shown by arrows F1.

Furthermore, the housing 30 comprises an inlet 52 and an outlet 54 for the fluid F2. In the example, this inlet and this outlet are circular openings made in the same side wall, namely one of the walls 38 of the housing.

The housing 30 thus delimits a chamber for the fluid F2 which circulates between the tubes 14, which makes it possible to define an alternating stack of blades for the circulation of the fluids F1 and F2. The arrangement of the openings 48 and 50 and the openings 52 and 54 is such that the two fluids circulate in counter-current to improve the heat exchange. The heat exchanger block of FIG. 1 is capable of numerous variants, in particular as regards the shape and dimensions of the housing and the location possibilities of the respective inlets and outlets for the two fluids.

Referring now to FIG. 2, there is shown a shell 20 to be assembled with an identical shell 20 to jointly form a flat tip 18. The shell 20 comprises a flat bottom 22 surmounted by a peripheral assembly edge 56 having a U-shaped outline. This assembly edge provides a contact surface 58 which is flat and is parallel to the general plane of the bottom 22. Thus, when two shells 20 are arranged vis-à-vis, that is that is, by turning their concavities toward each other, the joining surfaces 58 of the shells come into contact with each other and can be brazed together by delimiting a chamber, the respective bottoms 22 of the two shells being spaced apart to define an introductory slot for the end of a tube.

The assembly edge 58 has two free ends 60 located respectively on either side of a free edge 61 of the bottom of the shell. In the example, this free edge is right. When the two shells of the same pair are assembled, thus delimits a chamber for the fluid with a flat slot for the introduction of a tube end. This flat slot has an internal cross section of shape homologous to the external cross section of a tube so as to allow sealing assembly during soldering.

In the example of Figure 2, the bottom 22 of each shell comprises three communication openings, namely a main communication opening 24 located in a central region, near the bottom of the generally U-shaped contour, and two openings of secondary communication 62 arranged on either side of the main communication opening 24.

The shell 20 has a width, as defined between the two free ends 60 of the joining edge 56, which is at least twice its depth, as defined by the dimension in the perpendicular direction between the free edge 61 and the bottom In the example shown, the width of the shell is substantially equal to three times its depth, which gives a very open U shape, favorable to a good circulation of the fluid F1 in the collector boxes. entry and exit.

Each of the shells advantageously comprises positioning means capable of cooperating with the positioning means of a shell facing each other to enable them to be assembled in the correct position in order to constitute together a flat endpiece 18.

In the example shown in Figure 2, these means comprise a tab 64 and a notch 66 of homologous shapes spaced from each other and provided respectively in the vicinity of the two ends 60 of the assembly edge. Thus, when two shells are placed in facing relation, the tab 64 of each shell is received in the notch 66 of the other shell, which allows them to be positioned correctly for assembly by brazing.

As also seen in Figure 2, the flat bottom comprises three stops 68 formed each projecting from the side of the assembly edge to limit the introduction of the free end of a tube.

The shell 20 of Figure 2 can be advantageously made by stamping and cutting a metal plate, preferably an aluminum plate or aluminum alloy suitably coated with a solder plating.

Because each shell comprises a flat bottom, the flat bottom of one shell can be directly assembled against the flat bottom of an adjacent shell of another pair, i.e. another end, to realize their mutual assembly. This avoids making a collar around the opening 24 opposite the assembly edge.

In other words, the distance between two adjacent tubes 14 substantially corresponds to twice the material thickness of a said shell 20. And the height of the disrupter or spacer 16 is twice the thickness of material of a said shell 20, so that the folds of said spacers 16 are in contact with said tubes 12.

In the example described, the two shells are identical and independent pieces. It would be possible, however, to form the two shells in one piece with a fastener connecting the two shells and can be folded to bring the two shells closer to each other.

Reference is now made to FIGS. 3 to 5 which show a heat exchanger 70 constituted in this case by a condenser and comprising a condensing block 72 and a subcooling block 74, both made according to the teachings of the invention. , as well as a bottle 76 interposed between the blocks 72 and 74.

The condensation block 72 comprises a beam 12 (Figure 4) similar to that of Figure 1, which will not be described in detail. This beam is housed in a housing 78 formed of a housing 80 of generally parallelepipedal shape having a bottom wall 82, two large side walls 84 and two small side walls 86. An open face is thus defined which is closed by a cover 88 .

The subcooling block 74 is similarly constructed and comprises a beam 12 (FIG. 4) formed from the same components as the beam of the block 72, except that it comprises a smaller number of tubes. , bits and disrupters to achieve a beam of lower height, as seen in Figure 3. The heat exchange capacity of the block 74 is lower than that of the block 72. The beam of the sub-block cooling 74 is housed in a housing 90 having a housing 92 of generally parallelepipedal shape. This casing 92 comprises a bottom wall 94 connected to two large lateral walls 96 and two small lateral walls 98.

These side walls delimit between them an open face which is closed by a lid 100 of generally rectangular shape.

The side walls 84 of the block 72 as well as the side walls 96 of the block 74 are widened at the ends of the housing to accommodate respectively the inlet manifold and the outlet manifold for the first fluid F1. Thus, each of the side walls 84 has two opposing bosses 102 and each of the side walls 96 has two opposite bosses 104, in particular formed in continuity with the rest of the housings, for example by stamping. It may be the same in the configuration with single exchanger block (Figure 1).

According to these different embodiments, the side walls of the housing are in contact with the tubes 14, in their part located between the bosses. In other words, the inner width of the housing or casings, in their central part, corresponds to the width of the tubes 14, while in their enlarged part, that is to say at the level of said bosses, the inner width of the said one or more housings is greater than the width of said tubes, for example greater than the width of the shells. By width of the tubes, the housing or shells and / or shells means the dimension perpendicular to the plane defined by the longitudinal axis of the tubes and the stacking direction of said tubes. The bosses thus define manifolds for the second fluid F2.

If we focus again specifically on the embodiments of Figures 3 to 5, the chambers defined by the housings 78 and 90 communicate directly with each other through arrangements of the two bosses 102 and the two bosses 104, as seen on For this purpose, at least some of the bosses 102 and 104 have a communication opening for the circulation of the second fluid F2.

Thus, the bosses 104 of the same side wall 96 have an opening surrounded by a circular tip 106 received in an opening 108 of a boss 102 with interposition of a seal 110. Moreover, the opposing bosses 104 have an opening for receiving an inlet pipe 112 and an outlet pipe 114 for the fluid F2. Thus, the same fluid F2 can circulate in the respective housings of the two blocks, between the tubes of the respective beams. The fluid F2 which constitutes here a cooling fluid thus serves to cool the fluid F1 in the two blocks since it passes successively through the subcooling block 74 and the condensing block 72. In a variant, not shown, the second fluid F2 could separately feed the subcooling block 74 and the condensing block 72, the latter then having their own inlet and outlet for the fluid F2. The two blocks 72 and 74 are held together by tabs 116 and 118 as seen in FIGS. 3 and 4.

The lid 88 of the condensation block 72 is provided with an inlet flange 120 having an opening 122 for the admission of the fluid F1. This opening 122 supplies the input manifold of the corresponding beam 12. Furthermore, the cover 88 comprises an outlet opening 124 in which is fitted an end of a conduit 126 which is connected to a cover 128 of the bottle 76. This bottle houses a filtering and desiccating cartridge (not shown). From the cover 128, another duct 130 leads the fluid F1 to the subcooling block 74. This duct 130 opens into an opening 132 in the cover 100 which opens into the inlet manifold of the sub-cooling block 74. At its other end, the cover 100 includes an outlet flange 134 provided with an outlet opening 136. The cover 128 of the bottle 76 has a flange 138 for holding the ends of the conduits 126 and 130.

As a result, the fluid F1, in the example a refrigerant, enters the condensation block 72 through the inlet flange 120 and is cooled in the beam of this block by heat exchange with the fluid F2, leaves then the block 72 to win the bottle 76 in which it is filtered and dehydrated. Then, the fluid F1 gains the inlet opening 132 of the subcooling block 74, circulates in the beam of this block where it is cooled again by the fluid F2 and then leaves this block by the outlet flange 134.

In a condenser of this type, the refrigerant may be a phase change fluid such as a fluorinated fluid or a supercritical fluid such as CO2. The different components will be adapted according to the pressures to be withstood, in particular high pressures when it is a fluid of the CO2 type.

In this case, it will be advantageous to use flat tubes 25 made by extrusion and including internal channels of generally circular section.

Bottle 76 is substantially tangentially disposed to at least one of condensing block 72 and sub-cooling block 74 to reduce bulk. In the embodiment of FIGS. 3 to 5, where the two blocks are arranged so as to have two of their lateral walls 84, 96 facing each other, the bottle 76 is arranged tangentially to one of the side walls. 84 of the condensation block 72 and the cover 100 of the sub-cooling block 74, that is to say tangentially to two walls perpendicular to each other. This tangential arrangement of the bottle can be applied to other embodiments, in particular as to the embodiment of the bundle, such as stacked plate bundles or end plate bundles having a concavity oriented in the same direction. meaning, as discussed below. Such an arrangement makes it possible to propose a more compact heat exchanger than that described in document FR 2 846 733, mentioned above, which has a large bulk in the stacking direction of the plates.

Figures 6 and 7 refer to another heat exchanger in which the housing is made differently, that is to say without housing or cover as in the previous embodiments.

Here, the heat exchanger 140 comprises a housing 142 having a casing 144 of generally parallelepipedal shape having two large opposite side walls 146 and two small opposite side walls 148 for delimiting two opposite open faces, each of substantially rectangular shape. Each of these open faces is closed by a cheek 150 having a peripheral edge 152 provided with crimping tabs 154 adapted to grip a peripheral edge of the envelope with insertion of a seal (not shown). In such an embodiment, said flange 150 is, for example, secured, in particular brazed to the beam 12.

The heat exchanger 140, which may be for example a condenser, comprises tubings 156, 158, 160 and 162 for the admission or discharge of a fluid and which will not be described in detail. Likewise, one cheek 150 carries tubings 164 and 166 and another cheek 150 carries tubings 168 and 170 which will not be described in detail.

In the embodiments of FIGS. 3 to 5 and that of FIGS. 6 and 7, the inlet and outlet manifolds for the fluid F1 consist of stacked tips each formed by the assembly opposite the two shells having a bottom in which is arranged at least one communication opening. However, in an alternative embodiment, not shown, it is also conceivable to make each of the manifolds by a stack of end plates having a bottom provided with a peripheral edge with a generally U-shaped contour. end are then assembled in pairs in a sealed manner by cooperation of their respective peripheral edges, having all their concavity in the same direction. This solution avoids the use of pairs of shells and reduces the bulk in the direction of the stack.

The heat exchanger block of the invention is particularly suitable for producing heat exchangers for motor vehicles, in particular air conditioning condensers.

Claims (20)

Revendications1. Heat exchanger block comprising an alternating stack of channels for the circulation of a first fluid (F1) and channels for the circulation of a second fluid (F2), characterized in that it comprises a beam (12) formed by an alternating stack of flat tubes (14) for the circulation of the first fluid (F1) and disrupters (16) for the circulation of the second fluid (F2) between the tubes; flat ends (18) in which the respective ends of the tubes (14) are received, these ends (18) being each formed by the assembly facing two 1.5 shells (20) having a bottom (22) in which at least one communication opening (24) is arranged, to form two series of end pieces (18) at the respective ends of the bundle, the end pieces (18) of each series communicating with each other via their communication openings (24) for Forming an inlet manifold (26) and an outlet manifold (28) for the first fluid (F1); and a housing (30) enveloping the beam (12), said housing being provided with an inlet (48) and an outlet (50) for the first fluid (F1) and an inlet (52) and an outlet (54) for the second fluid (F2). 2. heat exchanger block according to claim 1, characterized in that the bottom (22) of each cogiille (20) is generally flat, which allows a direct contact 30 between the bottoms of two shells belonging to two endpieces ( 18) adjacent for their mutual assembly by brazing. 3. heat exchanger block according to one of claims 1 and 2, characterized in that the bottom (22) of each shell (20) is surmounted by a peripheral assembly edge (56) contoured generally U-shaped, said 16-edge assembly (56) having two free ends (60) located respectively on either side of a free edge (61) of the bottom of the shell, so that two shells assembled together by their respective connecting edges (56) define a fluid chamber with a flat slot for insertion of a tube end. 4. heat exchanger block according to claim 3, characterized in that each shell (20) has a width, as defined between the two free ends (60) of the joining edge (56), at least equal to twice its depth, as defined by the dimension in the perpendicular direction between the free edge (61) and the bottom of the generally U-shaped contour. 5. Heat exchanger block according to one of claims 1 to 4, characterized in that the bottom (22) of each shell (20) comprises a main communication opening (24) surrounded by two secondary communication openings 20 (62). 6. Heat exchanger block according to one of claims 1 to 5, characterized in that each shell (20) comprises positioning means (64, 66) adapted to cooperate with the positioning means (64, 66). ) of a shell vis-à-vis to allow their assembly in the correct position to form together a flat tip (18). 30 7. heat exchanger block according to claim 6, characterized in that the positioning means comprise a lug (64) and a notch (66) of homologous shapes spaced apart from each other. 35 8. Heat exchanger block according to one of claims 1 to 7, characterized in that the housing (30) comprises a housing (32) having a bottom wall (34) and side walls (36, 38) defining an open face (40) and a cover (42) for closing the open face of the housing. 9. heat exchanger block according to one of claims 1 to 7, characterized in that the housing (142) comprises a casing (144) having side walls (146, 148) defining two opposite open faces, and two opposing cheeks (150) for respectively closing the two open faces of the envelope. Heat exchanger block according to one of Claims 1 to 9, characterized in that the inlet manifold (26) and the outlet manifold (28) for the first fluid (F1) are housed in two end of the housing (30; 78; 90; 142). Heat exchanger block according to claim 10, characterized in that the housing (78; 90) has sidewalls (84; 96) enlarged at both ends for respectively housing the inlet manifold (26) and the outlet manifold (28) for the first fluid (F1). Heat exchanger block according to claim 11, characterized in that the side walls (84; 96) have opposed bosses (102; 104), at least some of which have a communication opening for the circulation of the second fluid ( F2). 13. Heat exchanger comprising at least one heat exchanger block (10; 72; 74) according to one of claims 1 to 12. 14. Heat exchanger according to claim 13, in the form of a condenser, wherein the first fluid 2947045 (F1) is a refrigerant and the second fluid (F2) is a cooling fluid. 15. Heat exchanger according to claim 14, characterized in that it comprises two heat exchanger blocks according to one of claims 1 to 8, namely a condensation block (72) and a block of sub-heat exchangers. cooling (74), and a bottle (76) arranged therebetween, so that the first fluid (F1), which is the refrigerant, passes successively through the condensation block (72), the bottle (76) and the subcooling block (74). 16. Heat exchanger according to claim 15, characterized in that it comprises an inlet flange (120) and an outlet flange (136) for the first fluid (F1) disposed respectively on the condensation block (72). and on the subcooling block, as well as conduits (126, 130) connecting the bottle (76) to the condensing block (72) and the subcooling block (74). 17. Heat exchanger according to one of claims 15 and 16, characterized in that the second fluid (F2), which is the cooling fluid, passes successively through the sub-cooling block (74) and the condensation block. (72). 18. Heat exchanger according to claim 17, characterized in that it comprises an inlet pipe (112) and an outlet pipe (114) for the second fluid (F2) both arranged on the sub-block. cooling (74), the second fluid (F2) passing from the subcooling block (74) to the condensing block (72) and then from the condensing block (72) to the sub-cooling block (74) through openings vis-à-vis arranged in the respective housings (78; 90) of said blocks (72; 74). 19. Heat exchanger according to one of claims 15 and 16, characterized in that the second fluid (F2), which is the cooling fluid, separately feeds the sub-cooling block (74) and the condensing block ( 72). 20. Heat exchanger according to one of claims 15 to 19, characterized in that the bottle (76) is disposed substantially tangentially to at least one of the condensation block (72) and the sub-cooling block (74).