EP1540223A1

EP1540223A1 - Heat exchanger, method for producing said heat exchanger and an extruded composite profile used for the production thereof

Info

Publication number: EP1540223A1
Application number: EP03807763A
Authority: EP
Inventors: Norbert William Sucke
Original assignee: Erbsloeh Aluminium GmbH
Current assignee: Erbsloeh Aluminium GmbH
Priority date: 2002-09-20
Filing date: 2003-07-29
Publication date: 2005-06-15
Also published as: WO2004033947A1

Abstract

The invention relates to a heat exchanger which can be produced on the base of an extruded composite profile and to a method for producing said heat exchanger. In the preferred embodiment, the inventive heat exchanges is made of aluminium or the alloy thereof and is used, in particular for an air conditioning system or for the cooling system of a car engine. (4,5). The use of the extruded composite profile consisting of individual tubes (20, 30) which are arranged in parallel with respect to each other and interconnected therebetween by means of jointing areas makes it possible to easily produce an internal heat exchanger. For this purpose, the jointing areas are separated at the level of the ends of the composite profile. In the preferred embodiment, the ends (23, 24) of every second individual tube (20) are connected therebetween by means of a coupling element (61, 63), the individual tubes (30) disposed between the individual tubes (20) being connected therebetween by means of another coupling element (62, 64). Said invention also makes it possible to produce an internal heat exchanger in which a coolant alternatively passes therethrough, thereby providing an excellent heat exchange.

Description

Heat exchanger and method for producing a heat exchanger and extruded Nerbundprofil for use in such

method

The invention relates to a heat exchanger, which can be produced from an extruded composite profile, and a method for producing such a heat exchanger, preferably made of aluminum or an aluminum alloy, in particular for an internal heat exchanger of an air conditioner or a cooling system of a motor vehicle.

An air conditioner generally has a compressor, a condenser, an expansion device and an evaporator. These components are usually arranged one after the other and connected to one another via fluid-conducting tubes. For a smooth operation of such an air conditioner, a so-called internal heat exchanger has been proven, on the one hand, the high-pressure refrigerant, which is passed to the expansion device, cools and on the other hand heated from the evaporator coming relaxed low-pressure refrigerant. In the previous vehicle air conditioning systems, refrigerants such as R134a had proven successful. These refrigerants are, however, due to their CFC components replaced by less environmentally harmful refrigerant. An alternative fluid for the refrigerant circuit of a motor vehicle air conditioning system is, for example, CO ₂ . However, carbon dioxide places more demands on an air conditioning system because it requires a higher operating pressure and therefore requires that the individual components of the system be designed for higher bursting pressures. From DE 100 53 000 AI an internal heat exchanger with a heat exchanger tube, which has a profiled central channel and around this grouped outer channels known. This

Heat exchanger tube is suitable for the construction of countercurrent heat exchangers, in particular for internal heat exchangers with CO ₂ refrigerant. The central central channel of the extruded heat exchanger tube is thereby flowed through by the high-pressure refrigerant. The outer channels surrounding the central channel receive the low pressure refrigerant coming from the evaporator. This low-pressure refrigerant is divided by the plurality of outer channels into different individual streams and can thus effectively release its heat to its environment. The high-pressure refrigerant flows through the central channel in a stream, ie, the heat exchange is achieved only by the wall of the central channel contacting fluid components. Although there are provided to improve the heat exchange projections in the central channel, but they cause j edoch disadvantageously a constriction of the channel. For the construction of an internal heat exchanger, which uses such a heat exchanger tube, fittings for the in and out of the refrigerant are necessary, wherein the fluid for the outer channels must be additionally divided into the individual channels. These fittings are complex in their construction and can not prevent low pressure losses of the refrigerant in the fittings.

The object of the invention is to provide an improved heat exchanger, in particular for an air conditioning system or a cooling system of a motor vehicle, which can be produced in a simple manner.

This object is achieved by a heat exchanger with the features of claim 6, which can be prepared in an advantageous manner by a method according to claim 18. In the production of the Heat exchanger finds an extruded composite profile according to claim 1 use.

The extruded composite profile according to the invention is constructed of parallel juxtaposed and interconnected individual tubes. When using the composite profile as a heat exchanger tube, these individual tubes can be flowed through alternately, preferably countercurrently, by the CO ₂ refrigerant. The composite profile can also be bent in an advantageous manner in the longitudinal direction, but also about its longitudinal axis. Bending the profile along the longitudinal axis allows flexible laying of the heat exchanger tubes. Due to the meander-shaped or spiral bending of the composite profile about the longitudinal axis, it is achieved that the individual pipes through which the high-pressure or low-pressure refrigerant flow reciprocally not only have contact with the adjacent pipes in the composite profile, but are in contact with further individual pipes arranged above or below them. As a result, the heat exchange improves in addition, because even the mutual flow through the individual tubes of high-pressure or low-pressure refrigerant leads to an extremely good heat exchange.

The extruded composite profile according to the invention can be further processed in an advantageous and simple manner to a heat exchanger. For this purpose, the individual pipes are separated at the two ends of the composite profile by separating at the compound site and all individual pipes, which are to be traversed by the CO ₂ high-pressure refrigerant, summarized at both ends in a connecting piece. This is realized for example in that these individual tubes are bent out of the plane of the composite profile, fitted into a connector and connected by brazing, welding or gluing with this connector. In the same way, the connection of the remaining individual tubes of the composite profile for the CO ₂ low-pressure refrigerant. However, the separation at the composite site occurs only at the ends of the composite profile. In a substantial area of the longitudinal extent of the composite profile, the connection between the individual tubes is maintained and thus enables good heat conduction between the adjacent individual tubes through which different media flow. In this area, which is necessary for the heat exchange, the composite profile can be present as a flat profile, but also-as described above-can have a U-shaped, circular, spiral or meandering curved cross-section. In addition, it is conceivable to twist the composite profile in this area. This results in a further increase in the efficiency of the heat exchanger.

Further details of the invention are given in the dependent claims and the following description of embodiments of the invention with reference to drawings. Show it:

1 is a perspective view of an extruded composite profile according to the invention,

2 is an enlarged cross-sectional view of the composite profile according to the invention shown in FIG. 1,

Fig. 3 is provided for the production of a heat exchanger

Composite profile in a perspective view,

Fig. 4 shows a heat exchanger with a flat extruded

Composite profile,

5 shows a cross section through a heat exchanger with a meandering curved composite profile, 6 shows a cross section through a heat exchanger with a sprial-shaped composite profile and

Fig. 7 shows a heat exchanger with a circular curved

Composite profile in a perspective view.

In Fig. 1 an inventive extruded composite profile 10 is shown. The composite profile 10 is preferably made of aluminum or an aluminum alloy. This integrally extruded composite profile 10 consists of several individual tubes 20, 30, in this case the same outer and inner geometry. The individual tubes 20, 30 are arranged alternately, side by side and connected to each other via a tear bar 40. These individual tubes 20, 30 have a flat profile cross-section and each have a cavity 21, 3 1, which is enclosed by a profile wall 22, 32. As can be seen better from FIG. 2, the individual tubes 20 have a profile wall 22 with a wall thickness w2 and the individual tubes 30 have a profile wall 32 with a wall thickness w3. The two individual tubes 20, 30 connecting composite site 40 has a wall thickness w4, which is less than the wall thicknesses w2 and w3 of the profile walls 22, 32 of the individual tubes 20, 30. The width b of the compound site 40 is dimensioned as small as possible to a good heat exchange between the individual tubes 20, 30 to ensure. This is achieved with widths b of 0, 1 to 0.3 mm. Such an inventive composite profile 10 is obtained by quasi-continuous extrusion, wherein the extruded from the extruder strand is fed to a separation device, preferably a CTL device, where the profile strand is divided into desired lengths of the composite profile 10. If necessary, the profile strand after leaving the extruder a coating device with subsequent drying / curing and / or cooling can be supplied. In this way, a coated composite profile 10 is obtained after the separation of the profile strand. Conceivable would be a zinc, Flux or solder coating. If the composite profiles 10 are to be processed at a later time or at a different location, the profile strand can also be wound on a spool in the meantime.

The composite profiles 10 shown in FIGS. 1 and 2 have individual tubes 20,

30 with the same external and internal geometry on. However, it is also possible to provide differently shaped individual tubes 20, 30 in the composite profile 10. Thus, the flow cross-section of the cavity 21 may be smaller, equal to or greater than the flow area of the cavities 31 of the single tube 30. Also, the cross-sectional shape of the cavity 21,

31 and does not have to have an oval shape as shown in this example. Likewise, the shape of the individual tubes 20, 30 is not limited to a flat profile cross-section. There are also other Querschnittsfomren, in particular round tube profiles possible. Also, according to the intended use as a high-pressure or low-pressure line, the respective individual tube 20 or 30 can be equipped with a different wall thickness w2 or w3. In this case, however, it should be ensured that the wall thickness w4 of the composite site 40 is at least 20% lower. For a particularly good separation of the individual tubes 20, 30, the offset by a paragraph 41 composite point 40, preferably provided with at least one predetermined breaking point 42.

Such an extruded composite profile 10 according to the invention can advantageously be used for producing a heat exchanger, in particular for an internal heat exchanger in an air conditioning system or for a cooling system of a motor vehicle. In such a heat exchanger, the adjacent individual tubes 20, 30 can be flowed through by different media 51, 52. A mutual flow through adjacent individual tubes 20, 30 ensures a good heat exchange. For example, the individual tubes 20 of the cold CO high-pressure refrigerant flows through and the individual tubes 30 of the comparatively warm CO ₂ low-pressure refrigerant and the arrangement of the individual tubes 20, 30 is selected in the heat exchanger so that each between two individual tubes 20, a single tube 30 is arranged, j eder individual flow of the fluid 51 each with a single flow of the fluid 52 via the j eweilige profile wall 22, 32 of the individual tubes 20, 30 in contact. Such heat exchange is significantly more intense than in a coaxial tube of the prior art, where a fluid in a stream passes through the central channel.

Since there is an internal heat exchanger in an air conditioner, in which the refrigerant is circulated, it must be ensured at the two ends of the composite profile 10 that the individual streams are each combined in a connector. From where then go the refrigerant lines to the condenser or the expansion device for_ the high-pressure refrigerant or to the evaporator and compressor for the low-pressure refrigerant, which is not shown in the figures. The separation of the individual tubes 20, 30 is possible in a simple manner, for example by horizontal or vertical bending of the individual tubes. When used as a heat exchanger, however, it is only necessary to bend the ends 23, 24 of the individual tubes 20 and / or the ends 33, 34 of the individual tubes 30 out of the plane of the composite profile, ie in a substantial region B of the longitudinal extent of the composite profile 10 the connection between the individual tubes 20, 30 is maintained. As can be seen from the exemplary embodiment in FIG. 3, the ends 33, 34 of the individual tubes 30 can also remain unchanged and only the ends 23, 24 of all the individual tubes 20 can be bent simultaneously or successively. In this case, the ends 23, 24 of the individual tubes 20 were each bent upwards out of the plane of the composite profile 10. In which direction the bending of the ends 23, 24 or 33, 34 takes place is not essential to the invention. It only has to be achieved that all ends 23 of the individual tubes 20 in a connecting piece 61 and all ends 33 of the individual tubes 30 open into a connecting piece 62. Similarly, on the other side of the composite profile 10, the ends 24 are received by a fitting 63 and the ends 34 by a fitting 64. In the example of a heat exchanger shown in Fig. 4, the individual tubes 20 are flowed through by the fluid 51 in the direction 53 and the individual tubes 30 from the fluid 52 in the opposite direction 54. In the fluids 5 1, 52 are at an inner heat exchanger to refrigerant different Temperature and pressure conditions, preferably around CO ₂ , which has no negative influence on the greenhouse effect. However, the heat exchanger according to the invention is not limited to the use of CO ₂ refrigerant.

The perspective view of the heat exchanger in Fig. 4 does not quite correspond to the actual conditions, since of course the ends 23, 24 and 33, 34 are kept as short as possible in their longitudinal extent so the area B, where the intense heat exchange between the fluids 51, 52nd takes place as large as possible. In cross section, the heat exchanger of FIG. 4 shows a flat profile, as shown in Fig. 1. However, it is also possible to bend the composite profile 10 in the region B about the longitudinal axis L. In this way, additional contacts between the individual tubes 20, 30 can be created. In FIG. 4, each individual tube 20 is arranged so that it touches the adjacent individual tubes 30 and is in heat exchange with it. By bending the composite profile 10 about the longitudinal axis cross sections, as shown for example in Figures 5 and 6, can be achieved. The meandering curved composite profile 10 according to FIG. 5 or the spirally curved composite profile 10 according to FIG. 6 clarifies that in each case a single tube 20 is in addition to the adjacent individual tubes 30 with above or below arranged individual tubes 30 in heat exchange. This increases the efficiency of the heat exchanger. A cross-section, as in FIG. 5, can also be achieved by a plurality of flat composite profiles 10 arranged one above the other, as shown in FIG. 1 known, received. In a heat exchanger according to FIG. 6, it is advantageous if the size of the individual tubes 20, 30 decreases from outside to inside. As a result, the spiral deformation is simplified and guarantees that individual tubes 20 are always surrounded by individual tubes 30.

In addition to the above-described bending of the composite profile 10 about the longitudinal axis L, a twisting of the composite profile 10 in the region B is also conceivable, as is known in particular from the coaxial tubes.

Fig. 7 shows an embodiment of a composite profile 10, which is composed of adjacent individual tubes 20, 30 and was bent around its longitudinal axis to a, annular cross-section composite profile. In this example, it is shown that the composite profile 10 for the heat exchanger can also be made flexible in the longitudinal direction, that is adaptable to predetermined constructions. In Fig. 7, the composite profile 10 is surrounded by a sleeve 70 for protection. This sleeve 70 may for example also be a hose.

T h e S e c tio ns:

0 Composite profile 0 Single pipe 1 Cavity 2 Profile wall 3 End 4 End 0 Single pipe 1 Cavity 2 Profile wall 3 End 4 End 0 Joint 1 Paragraph 2 Predetermined breaking point

51 fluid

52 fluid

53 flow direction of 51

54 flow direction of 52

61 connection piece

62 connection piece

63 connection piece

64 connection piece 70 sleeve

B range of 10 b width of 40

L longitudinal axis of 10 w2 wall thickness of 22 w3 wall thickness of 32 w4 wall thickness of 40

Claims

Claims:

Extruded composite profile, preferably made of aluminum or aluminum alloy, for an internal heat exchanger of an air conditioning system of a motor vehicle, the one-piece extruded composite profile (10) being constructed from at least two individual tubes (20, 30) of the same or different external and internal geometry,

the individual tubes (20, 30) have a round or flat profile cross section, the individual tubes (20, 30) having a profile wall (22, 32) surrounding a cavity (21, 31) with a wall thickness (w2, w3),

characterized in that

the individual tubes (20, 30) are arranged next to one another and connected to one another via a connection point (40),

wherein the connection point (40) has a minimum width (b) of 0.1 to 0.3 mm, which corresponds to the distance between two adjacent individual tubes (20, 30) and

wherein at the connection point (40) the wall thickness (w4) is at least 20% less than the wall thickness (w2, w3) of the profile wall (22, 32) of the adjacent individual tubes (20, 30).

2. Extruded composite profile according to claim 1, characterized in that all the individual tubes (20, 30) have the same inner and outer geometry.

3. Extruded composite profile according to claim 1 or 2, characterized in that all individual tubes (20, 30) show a round profile cross section.

4. Extruded composite profile according to claim 1 to 3, characterized in that the individual tubes (20, 30) arranged next to one another are connected to one another via a composite point (40) set back from the shoulder (41) and this composite point (40) with at least one predetermined breaking point (42) is provided.

5. Extruded composite profile according to claims 1 to 4, characterized in that the outer surfaces of the profile wall (22, 32) of the individual tubes (20, 30) are provided with a coating.

6. heat exchanger, in particular for an internal heat exchanger of an air conditioning system of a motor vehicle,

with individual tubes (20) through which a fluid (51) flows,

with individual tubes (30) through which a fluid (52) flows,

characterized in that the individual tubes (20, 30) are part of a composite profile (10) in a region (B) of their longitudinal extent, the individual tubes (20) via their profile wall (22) and / or via a connection point (40) with a profile wall (32) the individual tubes (30) are in contact,

all individual tubes (20) open at one end (23) in a common connection piece (61) and at their other end (24) in a common connection piece (62) and

all individual tubes (30) open at one end (33) into a common connection piece (63) and at their other end (34) into a common connection piece (64).

7. Heat exchanger according to claim 6, characterized in that the individual tubes (20, 30) in the area (B) are arranged side by side in a flat composite profile (10), preferably one individual tube (30) between two individual tubes (20) ) and there is a connection of the adjacent individual pipes (20, 30) via the connection point (40).

8. Heat exchanger according to claim 6, characterized in that the individual tubes (20, 30) in the area (B) side by side in a meandering curved composite profile (10) and connected via the connection point (40), preferably between two individual tubes (20) in each case there is a single tube (30) and a single tube (20) has, in addition to the contact with the single tube (30) adjacent in the composite profile (10), a contact with other individual tubes (30) (FIG. 5).

9. Heat exchanger according to claim 6, characterized in that the individual tubes (20, 30) in the area (B) side by side in one Spirally bent composite profile (10) are arranged and connected via the composite point (40), wherein there is preferably a single tube (30) between two individual tubes (20) and a single tube (20) in addition to the contact with the in the composite profile (10) adjacent single tube (30) has a contact to further individual tubes (30) (Fig. 6).

10. Heat exchanger according to one of claims 6 to 9, characterized in that the fluid (51) has a total flow cross-section (Gl) and the fluid (52) has a total flow cross-section (G2), the total flow cross-section (Gl) being the sum of the cavity cross-sectional areas of the cavities (21) corresponds to the individual tubes (20) and the total flow cross-section (G2) corresponds to the sum of the cavity cross-sectional area of the cavities (31) of the individual tubes (30).

1 1. Heat exchanger according to one of claims 6 to 10, characterized in that outside the area (B) there is a separation of the individual tubes (20, 30) by separating the connection point (40).

12. Heat exchanger according to one of claims 6 to 1 1, characterized in that outside the area (B) all separated individual tubes (20) at their ends (23) and / or at their ends (24) in a direction towards the respective connector (61, 62) are bent.

13. Heat exchanger according to claim 12, characterized in that outside the area (B) the ends (33, 34) of the separated individual tubes (30) are bent.

14. Heat exchanger according to one of claims 6 to 13, characterized in that in the area (B) the flat, meandering or spirally curved composite profile (10) is additionally twisted in the longitudinal direction.

15. A method for producing a heat exchanger, preferably made of aluminum or aluminum alloy, in particular for an internal heat exchanger of an air conditioning system of a motor vehicle,

characterized in that

a extruded profile made up of individual tubes (20, 30) of the same or different outer and inner geometry, the individual tubes (20, 30) arranged next to one another being connected to one another via a connecting point (40), are extruded,

the profile strand emerging from the extrusion press is fed to a separating device, where desired lengths of the composite profile (10) are separated from the profile strand,

the connection point (40) between the individual tubes (20, 30) is torn open at the ends of the composite profile (10),

the ends (23) of the individual tubes (20) with a connecting piece (61), the ends (24) of the individual tubes (20) with a connecting piece (62), the ends (33) of the individual tubes (30) with a connecting piece (63) and the ends (34) of the individual tubes (30) are connected in a fluid-tight manner to a connecting piece (64).

16. The method according to claim 15, characterized in that after the extrusion a coating with subsequent Drying / curing and / or cooling of the profile strand takes place, preferably a zinc, flux or solder coating.

17. The method according to claim 14 or 15, characterized in that for storing and / or transporting the profile strand before separating the individual composite profiles (10) is in the meantime coiled onto a coil and is decoiled at a later time or at another location.

18. The method according to any one of claims 15 to 17, characterized in that the tearing of the connection point (40) of the composite profile (10) is preferably carried out by vertically opening the connection between the individual tubes (20, 30) arranged next to one another.

19. The method according to claim 18, characterized in that for tearing open the joint (40) the ends (23, 24) of the individual tubes (20) one after the other or simultaneously in a common direction out of the plane of the composite profile (10), preferably be bent upwards.

20. The method according to claim 19, characterized in that in order to tear open the connection point (40) in each case the ends (33, 34) of the individual tubes (30) one after the other or simultaneously in a common direction out of the plane of the connection profile (10), preferably after below, be bent.

21. The method according to claim 19, characterized in that for tearing open the connection point (40) the ends (33, 34) of the individual tubes (30) do not change their position in the plane of the connection profile (10).

22. The method according to claim 18, characterized in that the ends (23, 24) of the individual tubes (20) are punched out one after the other or simultaneously from the composite profile composite profile (10) for tearing open the composite point (40).

23. The method according to any one of claims 15 to 22, characterized in that before or after connecting the ends (23, 24; 33, 34) of the individual tubes (20, 30) with the connecting pieces (61, 62, 63, 64) the flat composite profile (10), preferably in an area (B), is bent about its longitudinal axis (L).

24. The method according to claim 23, characterized in that the bend about the longitudinal axis (L) leads to a cross-sectionally spiral or meandering shaped composite profile (10), in which the individual tubes (20) in addition to the adjacent individual tubes (30) in addition come into contact with further individual tubes (30).