EP1548385A2 - Heat exchange tube with two flow passages and heat exchanger provided with such tubes - Google Patents

Abstract

The exchanger has a collector plate (50) comprising openings to receive flat tubes (46), each comprising an insert with corrugations disposed in fluid flow direction. Each tube has a cut (48) at the level of a central partition to permit a separation wall (38) to be applied tightly on a support surface of a joint (52), where the wall divides a cover (40) of a collector box (36) into chambers (42, 44).

Description

The invention relates to the field of heat exchangers, especially for motor vehicles. It concerns a tube able to be part of a heat exchanger such as a engine cooling radiator of a vehicle automobile.

More particularly, it relates to a flat tube for a heat exchanger, having an insert having a pleat intermediate, in particular a central fold, forming a partition separating the two circulation channels for one coolant.

It also relates to a heat exchanger, in particular for a motor vehicle, comprising at least one row of flat tubes with two fluid circulation channels delimited by a partition wall, a plate collector with openings for receiving the tubes, a cover to close the collector plate and thus form a collector box, as well as a plane seal arranged on the manifold plate to ensure a tightness with the lid. The collector box is then divided by a partition to delimit two rooms that communicate respectively with a first channel and a second channel of each tube, the circulation of the fluid in the channels of each tube being counter-current.

Already known, according to GB 2 166 862 A, a heat exchanger tube of the type defined above. In each tube is inserted a profile which, on the one hand, forms a central partition of separation which allows delimiting two channels of circulation of fluid and which, on the other hand, generates turbulence in the fluid flow.

However, a tube of this type has disadvantages. he leads to high pressure drops. On the other hand, exchange surface between the fluid and the insert is little important.

With regard to the heat exchanger, there are known patent publications (eg EP 0 764 823 A1 and EP 0 964 218 A2) which describe heat exchangers comprising a row of tubes with two circulation channels delimited by a partition and a dividing wall, arranged in the collector box, in order to divide it into two bedrooms. However, all of these documents concern exchangers assembled by brazing.

The invention relates to a heat exchanger which can be realized not only in the form of an assembled exchanger by brazing, but also in the form of a heat exchanger heat mechanically assembled.

In the case of an exchanger assembled by soldering, the tubes are brazed in the openings of the collector plate and the seal ensures only the seal between the collector plate and lid.

However, in the case of a mechanically assembled exchanger, the seal between the tubes and the collector plate is obtained through the same seal, the end of the tubes being flared to compress the seal sealing.

The realization of an assembled heat exchanger mechanically poses specific problems that are not resolved by the documents cited.

Accordingly, the invention relates to a heat exchanger tube of heat with two circulation channels generating losses of reduced load and allowing a high contact surface between the coolant and the tube. -

These objects are achieved, according to the invention, by the fact that the insert has corrugations and the fact that at least one of these undulations constitutes the partition of separation.

The presence of corrugations makes it possible to increase the surface of the insert, and therefore the exchange surface between the tube and the coolant. On the other hand, the ripples being arranged in the direction of fluid flow, they do not generate significant loss of expenses.

Preferably, the corrugations of the insert located on the else of the ripple forming the partition wall have louvers, that is to say openings or openings allowing the fluid to pass through the corrugations at within the same channel.

These louvers allow a better homogenization and a better distribution of the fluid in the two channels of circulation.

The corrugations of the insert located on both sides of the ripple forming the partition wall extend from preferably over the entire height of the tube between two walls opposed.

The corrugations of the insert located on both sides of the ripple forming the partition wall can have the same shape as this last wave, or they may have a different form from the latter ripple.

The intermediate fold is preferably located substantially at the half-width of each of two opposite walls of the tube, to form a central fold.

However, it is also conceivable that the intermediate fold offset from the mid-width of each of two opposite walls of the tube so as to constitute a fold off center.

In an alternative embodiment, the tube is closed at a end, the insert having a length less than length of the tube in order to provide a free passage changing the direction of circulation of the fluid.

In another embodiment, the tube is open to both ends.

In this case, the circulation of the coolant can in the same direction in the two channels of circulation. Or, the second open end of the tube can be connected to a second collector box in which changes the direction of movement of the fluid.

The particular problems involved in achieving a heat exchanger, brazed type or assembled type mechanically, are solved by the fact that the box collector is divided into a first and a second chamber by a partition wall and by the fact that each tube has a cut-out at its partition wall to allow the separation wall of the box collector to apply with sealing on a surface of the seal, which is inserted into the cutting.

In the case of a mechanically assembled exchanger, the tubes dishes are mechanically assembled to the collector plate, the seal also ensuring a seal between flat tubes and openings of the collector plate.

In the case of an exchanger assembled by soldering, the tubes dishes are soldered to the collector plate, the seal sealing only ensures a seal between the plate collector and the lid.

Advantageously, the tubes of the heat exchanger have undulations, one of these undulations constituting the partition wall.

However, this achievement is not the only one possible. The partition wall can also be constituted by a strut, or by two half-legs of strength. The tubes of the exchanger can also be constituted by the assembly two single-channel tubes.

• la figure 1 est une vue schématique montrant la réalisation générale d'un échangeur de chaleur à tubes ;
• la figure 2 est une vue de détail en coupe qui explique l'assemblage des tubes à la plaque collectrice dans un échangeur de chaleur assemblé mécaniquement ;
• la figure 3 est une vue de détail en coupe, analogue à la figure 2, qui explique l'assemblage des tubes à la plaque collectrice dans un échangeur de chaleur assemblé par brasage;
• la figure 4 est une vue de détail en section transversale de la boíte collectrice d'un échangeur de chaleur conforme à l'invention ;
• la figure 5 est une vue schématique en coupe d'un tube conforme à l'invention comportant un insert possédant des ondulations ;
• les figures 6 et 7 illustrent deux variantes de réalisation du tube et de l'insert de la figure 5 ;
• les figures 8 et 9 sont respectivement une vue en perspective du tube de la figure 5 et de l'insert de ce tube ;
• la figure 10 est une vue en plan du joint d'étanchéité de l'échangeur de chaleur, de type à assemblage mécanique, de la figure 3 ;
• la figure 11 est une vue en plan d'un joint d'étanchéité pour un échangeur de chaleur, de type à assemblage brasé ; et
• les figures 12 à 14 illustrent différentes variantes de réalisation d'un tube destiné à un échangeur de chaleur tel que celui de la figure 4.

Other features and advantages of the present invention will become apparent upon reading the following description of exemplary embodiments given by way of illustration with reference to the appended figures. In these figures:

• Figure 1 is a schematic view showing the general embodiment of a tube heat exchanger;
• Figure 2 is a detail sectional view that explains the assembly of the tubes to the header plate in a heat exchanger mechanically assembled;
• Figure 3 is a detail sectional view, similar to Figure 2, which explains the assembly of the tubes to the header plate in a heat exchanger assembled by brazing;
• Figure 4 is a detail view in cross section of the collector box of a heat exchanger according to the invention;
• Figure 5 is a schematic sectional view of a tube according to the invention comprising an insert having corrugations;
• Figures 6 and 7 illustrate two embodiments of the tube and the insert of Figure 5;
• Figures 8 and 9 are respectively a perspective view of the tube of Figure 5 and the insert of this tube;
• Fig. 10 is a plan view of the mechanical assembly type heat exchanger seal of Fig. 3;
• Fig. 11 is a plan view of a seal for a brazed joint type heat exchanger; and
• FIGS. 12 to 14 illustrate various alternative embodiments of a tube intended for a heat exchanger such as that of FIG. 4.

The heat exchanger shown in FIG. tube bundle 10 arranged between two collector boxes 12 and 14. The tubes 10 alternate with corrugated spacers 18. An interlayer, disposed between two adjacent tubes 10, comes to the respective contact of the two tubes by regions end of the waves.

In an exchanger of this type, the tubes 10 exhibit a form generally flat, that is to say they are delimited by two large parallel faces that are joined together by two small faces, flat or curved. These tubes have an end inserted into the collector box upper 12 and another end inserted into the box 14. The heat exchanger may also be have only one collector box. In that case, the lower end of the tubes is closed and the circulation fluid occurs alternately in one direction and then in the other inside the tubes. Exchangers of the type represented in FIG. 1 can be assembled by brazing.

However, the invention also relates to a heat exchanger mechanically assembled as shown in FIG. exchanger assembled by soldering as shown in FIG. 3. As seen in Figure 2, a header plate 20, also called collector or tube plate, is perforated elongated openings whose shape corresponds to the section of the tubes. One end 24 of the tube 10 is received in the perforation 22. A seal 26 is disposed on the slip plate 20. This seal has openings 28 which are superimposed on the openings 22 of the header plate.

In a first step, each tube 10 is introduced at through the manifold plate 20 through the opening 22 and the opening 28 of the seal 26. Then the end 24 of the tube is enlarged to pinch the seal in order to provide a tight connection between the manifold plate 20 and the end of the tube 10. A cover 30 closes the header plate 20 so as to make the collector box 12 or 14. The lid 30 is provided with a peripheral rim 32. Tabs 34 cut in the collector plate 20 are folded and crimped onto the peripheral rim 32 so as to apply the latter on the seal 26. Thus, the seal 26 carries a part of the seal between the tubes and the header plate 20 and, on the other hand, the seal between the lid 30 and the In Figure 2, the internal volume of the collector box 12 is only one chamber.

In the case of a solder exchanger (FIG. 3), the end 24 of each tube 10 is brazed in the opening corresponding to the header plate 20, and the seal 26 only tightens between the cover 30 and the box 20. In another embodiment, no shown, the lid can be made of a material metallic. In this case, the assembly between the lid and the collector box can be done by soldering, which avoids use a gasket.

The invention relates, on the contrary, to a collector box 36, as shown in FIG. 3, comprising a wall of separation 38 which divides the interior volume of the lid 40 in a first chamber 42 and a second chamber 44. In additionally, in accordance with another characteristic of the invention, each of the tubes 46 can have a cutout 48 disposed in the extension of the partition wall 36 when the tubes are in place in the header plate 50.

A seal 52 is disposed on the header plate 50.

There is shown in Figure 10 a top view of the seal 52 in the case of a mechanical assembly exchanger. He owns an elongated rectangular general shape whose shape corresponds to that of the header plate 50. It is perforated openings 54 arranged opposite the openings of the collector plate 50. The shape of these openings corresponds to the outer section of the tubes 46. However, the openings 54 are divided into two zones 54a and 54b by a tongue 56 arranged, in the example, along the median axis XX of the seal 52. When the tubes 46 are inserted into the openings of the collector plate 50, the tongue 56 is placed at inside the cut 48.

Advantageously, the width of the tongue 56 adapts to the width of the cut. Thanks to the presence of the cutout 48, the partition wall 38 may be applied to the seal 52 and more precisely on the median part of the joint defined by the tongue 56. This provides a seal between the first and second chamber 42, 44 of the collector box 36. Sealing between tubes 46 and the collector plate 50 (in the case of a mechanical assembly exchanger) is performed, conventionally, by flaring out of the upper end of the tube as described in reference to Figure 2. In addition, the seal between the peripheral rim 58 of the lid 40 and the plate collector 50 is conventionally made as also described with reference to FIG. that the seal 52 provides a triple function.

In the case of a brazed joint heat exchanger, the joint shall ensure a dual function, namely on the one hand the tightness between the peripheral rim of the lid and the box collector, and on the other hand the sealing at the level of partition wall 38 of the collector box. The seal 52 shown in Figure 11 is appropriate for a brazed assembly exchanger. It includes a ledge peripheral 59 of generally rectangular shape and a tongue 56 disposed along the median axis XX of the seal. This tongue comes to the assembly, to seal between the collector plate and the partition wall of the lid.

FIG. 5 shows a sectional view cross section of a tube 46 of the exchanger shown in FIG. figure 4. This is a flat tube of rectangular section delimited by two large parallel faces united by two small parallel faces. The distance between the big faces corresponds to the height H of the tube, or to the width of the rectangular section. An insert designated by the reference 60 is inserted inside the tube 46. The insert 60 comprises, in accordance with the invention, an intermediate fold 62, here a central fold, which extends from one wall 63 to the other wall 65 of the tube (between the large faces). So when the tube is brazed, the central fold 62 makes a separation of a first channel 66 and a second channel 68 for the circulation of a coolant.

The central fold 62 is smooth and has a V-section and comes in sealed contact with the inside of walls 63 and 65 to delimit a "dead channel" 69 in which no fluid circulates. This channel 69 is materialized by hatching on the Figures 5 and 8.

In addition, the insert 60 has, on both sides of the fold central 62 corrugations 70 that improve the heat exchange between the fluid flowing in the tubes 46 and the walls of the tube itself. The corrugations 70 can, as shown in FIG. 4, extending from the wall 63 to the wall 65 over the entire height H of the tube. In others In other words, the amplitude of the corrugations 70 can be equal to that the central fold 62. This then means, in the example, that the central fold 62 and the corrugations 70 have the same shape. These ripples can present a substantially sinusoidal or a form formed by segments rectilinear connected two by two by rounded.

In the case of FIGS. 5 and 8, the intermediate fold 62, or central fold, and the corrugations 70 have the same shape defined by a V-shaped section. However, the middle fold and the ripples can have different shapes, like illustrated in Figures 6 and 7.

FIG. 6 shows an intermediate fold 62 of shape frustoconical and corrugations 70 having a section V, while Figure 7 shows an intermediate fold 62 having a V section and corrugations 70 of frustoconical shape. In the case of Figures 5, 6 and 7, the intermediate fold is located substantially at the mid-width L / 2 of the walls 63 and 65 and then constitutes a central fold.

However, the intermediate fold may be off-center or off-set compared to the mid-width to then form an off-center fold.

The shape of the insert is susceptible of many variants, Figures 5, 6 and 7 are given by way of example.

In the case of Figures 5, 6 and 7, preferably as shown in FIG. 9, the insert 60 comprises shutters 72 which allow the passage of the coolant from one wave to another, except for the middle fold 62 (here the central fold 62) which is smooth and does not have any shutters. These louvers are openwork or openings allowing the fluid to cross the thickness of the insert while remaining in the same channel 66 or 68. The circulation of the fluid in the channels 66 and 68 is effected by preference against the current, as illustrated by the arrows Figures 4 and 8.

In an alternative embodiment, the corrugations 70 can have an amplitude less than the height H of the tube and not include louvers.

The central fold 62, as shown in FIGS. 5 to 7, is found in the alignment of the partition wall 38. It is, on the other hand, located just under the tongue 56 (FIG. Figure 11). As a result, the sealing tongue 56 is tight between the central fold 62 and the end of the wall of separation 38. To obtain a good seal, it is necessary that the end of the central fold 62 be located in line with the surface of the plate collector 50 on which is disposed the seal 52. If the end of fold 62 is set back from this surface, a game may appear, leading to the appearance of leaks. On the contrary, if the end of the fold central 62 protrudes above the surface of the plate manifold 50, the tongue 56 of the seal 52 will be compressed excessively. It is therefore likely to be cut by the fold 62.

The tube described with reference to FIGS. 5, 8 and 9 represents a preferred embodiment of the invention. However, the heat exchanger described in FIG. receive other types of tubes. In Figure 12 we have represented a tube comprising two circulation channels 66 and 68 delimited by a strut 76. In Figure 14, the tube 78 has two channels 66 and 68 delimited by two half-legs of force 77.

Finally, in FIG. 10, a two-channel tube 82 was made in associating two tubes 84 to a single channel by their short sides 86. The two tubes 84 are brazed together so as to make a two-channel tube 66 and 68. Whatever the realization, the partition wall 76, 80 or 86 plays the same role as the central fold 62 of the tube described with reference in Figures 4 to 6.

The invention finds particular application to heat exchangers heat of motor vehicles and in particular to engine cooling radiators for these vehicles.

Claims (15)

Heat exchanger, in particular for a motor vehicle, comprising at least one row of flat tubes (46) having two circulation channels (66, 68) delimited by a partition wall (62, 76, 80, 86), a collecting plate (50) piercing tube receiving apertures (46), a cover (40) for closing the collector plate (50) and thereby forming a collector box (36) and a plane seal (52) disposed on the header plate (50) for sealing with the cover (40),
characterized in that the header (36) is divided into first and second chambers (42, 44) by a partition wall (38) and that each flat tube (46) has a cutout (48) at the its partition wall (62, 76, 80, 86) to allow the partition (38) to seal with a bearing surface (56) of the seal (52), which is inserted into the cutout (48). Heat exchanger according to Claim 1, characterized in that the flat tubes (46) are mechanically connected to the header plate (50) and in that the seal (52) also seals between the flat tubes (46). ) and the openings of the header plate (50). Heat exchanger according to Claim 1, characterized in that the flat tubes (46) are brazed to the header plate (50) and in that the seal (52) only provides a seal between the header plate (50) and the lid (40). Flat tube for a heat exchanger defined according to one of claims 1 to 3, comprising an insert (60) having an intermediate fold (62) forming a partition wall which defines two circulation channels (66, 68) for a fluid coolant, characterized in that said insert (60) comprises corrugations (70) and in that one of these corrugations constitutes the partition (62). Flat tube according to claim 4, characterized in that the corrugations (70) of the insert (60) located on either side of the corrugation (62) forming the partition wall comprise louvers (72). Flat tube according to one of claims 4 and 5, characterized in that the corrugations (70) of the insert (60) located on either side of the corrugation (62) forming the partition wall extend over the entire height (H) of the tube between two opposite walls (63, 65). Flat tube according to one of claims 4 to 6, characterized in that the corrugations (70) of the insert (60) located on either side of the corrugation (62) forming the partition wall have the same shape as this last undulation (62). Flat tube according to one of claims 4 to 6, characterized in that the corrugations (70) of the insert (60) located on either side of the undulation (62) forming the partition wall have a shape different from this last wave (62). Flat tube according to one of claims 4 to 8, characterized in that the intermediate fold (62) is located substantially at the mid-width (L / 2) of each of two opposite walls (63, 65) of the tube, to form a central fold. Flat tube according to one of claims 4 to 8, characterized in that the intermediate fold (62) is offset with respect to the half-width (L / 2) of each of two opposite walls (63, 65) of the tube, so as to constitute an off-center fold. Flat tube according to one of claims 4 to 10, characterized in that it is closed at one end, the insert (60) having a length less than the total length of the tube to allow the return of the coolant. Flat tube according to one of Claims 4 to 10, characterized in that it is open at both ends. Flat tube for a heat exchanger defined according to one of claims 1 to 3, characterized in that the partition wall is constituted by a strut (76). Flat tube for a heat exchanger defined according to one of claims 1 to 3, characterized in that the partition wall is constituted by two half-struts (77). Flat tube for a heat exchanger defined according to one of claims 1 to 3, characterized in that each tube (46) consists of two tubes (84) with a single channel assembled by a short side (86).

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