EP1511967B1 - Hollow chamber profile made of metal, especially for heat exchangers - Google Patents

Abstract

The invention relates to a hollow chamber profile made of metal, especially for heat exchangers. Said profile is made of an extruded base profile (10) having two broad parallel sides and two narrow sides or is made of a base profile which is a circular tube type or coaxial tube type. At least one channel (11) extends inside said base profile in the longitudinal direction thereof. The hollow profile has improved heat transfer properties on the sides and webs (13) which are deformed perpendicular to the longitudinal direction thereof.

Description

The invention relates to a hollow chamber profile made of metal, in particular for heat exchangers, consisting of an extruded base profile, which has the shape of a round tube or a coaxial tube or is equipped with two parallel broad sides and two narrow sides, wherein at least one channel in the interior of the base profile extends in the longitudinal direction.

This design of a hollow chamber profile for heat exchangers is from the German utility model DE 94 06 559 U1 known. There, the deformation of the channels forming webs during extrusion is shown in a simple manner. The profiling of the webs is not subsequently, but generated during extrusion. For this purpose, more extruded material is offered for that web which is to be profiled wavy, as for another web, which is not to be profiled wavy. This increased supply of the compressive material leads to a compression of the material and thus to an arbitrary deformation of the web to be pressed. Thus, an increase in the surface is achieved in a simple manner, resulting in improved heat transfer. However, the arbitrary deformation of the webs causes a channel which is bounded by two deformed webs to be narrowed or widened in the longitudinal direction of the profile. Such a change in the flow cross-section leads to pressure losses and thus to a lower heat exchange performance.

From the DE 100 49 987 A1 Furthermore, a cooler tube is known which has at regular intervals annular waves which extend radially outward and were generated by axial compression of the previously smooth cylindrical tube. Between the waves are smooth cylindrical pipe sections. Such a tube has due to its enlarged outer surface a relation to the smooth tube greater heat transfer. However, since the free flow cross-section at the points of the tube, where an annular shaft is provided, is increased, occur in the pipe flowing through the medium pressure losses and thus heat exchange losses. Furthermore, this tube has the disadvantage that the tube is influenced by the subsequently made axial upsetting in its strength.

As an alternative to extruded aluminum tubes or multi-chamber hollow profiles, aluminum profiles are used for roll-formed profiles. These are often closed by high-frequency welding or by suitable deformation and subsequent soldering. By using turbulators, the heat transfer properties can be improved. Disadvantage of this method is the high cost of manufacturing and mounting the turbulators. In addition, the soldered or welded pipe seams are frequent sources of failure in the case of mechanical or corrosive stress. By using extruded aluminum profiles, the task can only be partially solved. Although the pipe seams are considerably more stable, however, the suitability for heat transfer is limited by the only formed in the extrusion direction tube walls and pipe webs. Especially with gaseous media, such as. B. air in charge air coolers or CO ₂ or gaseous refrigerant in Klimaärmetauschern, heat can not be optimally transmitted.

The object of the invention is to provide hollow chamber profiles, in particular for heat exchangers, which have improved heat transfer properties compared to conventional extruded profiles and can be produced in a simple manner.

This object is achieved erfingdungsgemäß by a hollow chamber profile made of metal with the features listed in claim 1 or 5 and a method according to claim 8.

The hollow chamber profile according to the invention made of metal, in particular for a heat exchanger, is constructed from a base profile, which preferably consists of a corrosion-resistant, brazeable aluminum alloy, such as, for example, a 1xxx, 3xxx or 6xxx alloy. The extruded base profile has a round tube shape or a Koaxialrohrform or a flat tube shape with two parallel broad sides and two connecting these broad sides narrow sides. The interior of the basic profile is formed by at least one channel in the longitudinal direction. Perpendicular to the longitudinal orientation of the base profile are deformed opposite sides, with left-facing profiles and right-handed profiling alternate. These profiles are coordinated so that the width of the basic profile does not change over the entire longitudinal extent.

According to the invention, such deformations are provided in a flat-tube profile both on the narrow sides and on the webs extending from broad side to broad side of the basic profile and forming a plurality of channels. In any case, the profiles of the narrow sides and the webs are uniform. This is achieved by making all deformations simultaneously and in the same way. If, for example, a wavy deformation is provided in the longitudinal extent of the base profile, with the left and right-hand profilings alternating transversely to the longitudinal extent, the wave crests of the wavy course of each web and the two narrow sides engage in the corresponding wave troughs of the wave-shaped deformation of the respectively adjacent webs or narrow sides one.

In a tube profile, in particular a coaxial tube with several channels in the longitudinal direction, such deformations are provided both on the outer sides and on the webs forming the channels. In any case, the profiles of the outer sides and the webs are uniformly formed here as well.

It can be ensured in a preferred manner that the amplitudes of the wave-shaped course of the deformed sides and the webs in the entire hollow chamber profile are the same size, as well as can be provided for the wavelengths of the deformation. However, it is not necessary to achieve a high convection with consistently good heat transfer that the wave-shaped course of the deformations with unchanged wavelength and amplitude is equal. However, if the wavelength or amplitude of such a wavy course of deformation changes, this must apply equally to the adjacent webs as well as to the sides, so that in no case do two adjacent walls approach each other. The flow cross section of the channels is not changed by the deformations. However, the deformations represent turbulences for the gas flowing through the profile or the liquid flow, which are comparable to known turbulators which can be used. Such a verwelltes profile can be used both to increase the heat exchange performance of a gas stream and a liquid flow, the effect of the liquid flow, however, is generally lower. Advantageous application can find such a hollow chamber profile as a cooler, in particular as a CO ₂ gas cooler or as a charge air cooler for motor vehicles.

The hollow chamber profile according to the invention has over the previously known extruded profiles with parallel webs and undeformed narrow sides on a higher performance, since at the same good heat transfer through the turbulence generated by the deformation of the webs and narrow sides transverse to the gas or liquid flow, in addition a better convection is achieved.

Such a hollow chamber profile can be produced in a simple manner. In the first process step, a hollow profile strand, for example a round tube profile strand, a coaxial tube profile strand or a flat tube profile strand with two mutually parallel broad sides and arched or flat narrow sides, is produced by extrusion with at least one channel extending in the interior of the base profile. The emerging from the forming zone of the extruder and hot hollow profile strand is defined by an oscillating moving deformation tool vibrated and deformed. The deformed Hollow profile strand can then be cut to the desired length of a hollow chamber profile and, if necessary, provided with imprints on the pipe ends. These embossings are used for easy insertion into the headers and a perfect soldering to a heat exchanger.

Preferably, the emerging from the forming and hot hollow profile strand is acted upon by a perpendicular to the outlet direction of the profile strand oscillating moving deformation tool. At the same time both the narrow sides of the flat tube profile and the outer sides of the round tube profile and the possibly present webs are deformed.

In a particular embodiment, the deformations on the sides and on the webs have a wavy course in the longitudinal direction of the base profile. The wavelength of such a wave-shaped course is preferably unchanged for a hollow profile strand. This is achieved in that the oscillation frequency of the deformation tool is adapted to the strand exit speed of the hollow profile strand. In the production of multi-chamber hollow profiles extrusion rates of 15 to 200 m / min, preferably 60 to 150 m / min are used. The wavelengths of the wavy. Deformations of the profile strand can be of the order of 1 to 100 mm.

The deformation of the flat tube profile strand, i. the deflection is preferably in the direction of the tube width, so that the broad sides maintain their parallel course and are not deformed. This has the advantage that in the subsequent processing to the heat exchanger easy installation, especially the connection with cooling fins and headers can be done.

However, it is also possible to control two oscillation planes separately from each other and thus to produce circular eddies. this may be advantageous in particular in the case of a round tube profile or a coaxial tube profile.

The oscillating movement of the deformation tool generates a deflection force transversely to the outlet direction of the hollow profile strand. This deflection can be effected by mechanical pressure and shear forces. Likewise, an electromagnetic deflection of the hollow profile strand is possible. A particularly gentle action on the deflection of the hollow profile strand by the deformation tool is achieved by means of a fluid medium. Here, both air, nitrogen and water can be used.

Essential in the method according to the invention; that a hot hollow profile strand is deformed. This can be achieved by arranging the deformation tool in the immediate vicinity of the extrusion die. Thus, there is no noticeable cooling of the hollow profile strand after it emerges from the extrusion die and is then acted upon by the deformation tool. The temperature of the hollow profile strand in the deformation tool should be greater than 250 ° C, preferably more than 400 ° C, to allow a low-deformation deformation. If now the emerging from the extruder hot hollow profile strand is detected and deflected by the oscillating deformation tool, the deflection forces act back into the extrusion die and there influence the flow of material. Such a deformation tool can be arranged for example in a recess in the counter-spar of the extruder.

However, it is also conceivable that the emerging from the extrusion die hollow profile strand is led out of the extruder. In this case, it is advantageous to provide a corresponding device for guiding the profile strand between the extrusion press and the deformation device. Again, the high exit temperature of the hollow section strand is used to allow a low deformation deformation. However, it must be ensured that the hollow profile strand in the deformation tool has the desired forming temperature greater than 250 ° C.

In a further embodiment of the method according to the invention it is provided that the extrusion die itself as a deforming tool moving in an oscillating manner acts. The extrusion die or plant and tool components that position the extrusion die in the extrusion press perform an oscillating motion during the extrusion molding process.

With the method according to the invention, hollow-chamber profiles can be provided with wave-shaped deformations, although, in contrast to the prior art, these are defined wave characteristics that can be produced in a defined manner, ie. around reproducible amplitudes or wavelengths of the corrugations. As a result, a hollow chamber profile is produced, which over the entire longitudinal extent of the profile has an always constant free flow cross-section and constant wall thicknesses. It is achieved an increase in the heat exchange surface without high pressure losses can occur in the profile. At the same time, the laminar flow is disturbed by the swellings. These turbulences advantageously increase the heat exchange performance of the profile.

Fig. 1

eine perspektivische Ansicht eines erfindungsgemäßen Hohlkammerprofils,

Fig. 2

einen Querschnitt des Hohlkammerprofils gemäß Fig. 1,

Fig. 3

ein Längsschnitt durch das Hohlkammerprofil entlang Schnittlinie III - III gemäß Fig. 1,

Fig.4 a

die prinzipielle Darstellung einer erfindungsgemäßen Verfahrensvariante für ein Rundrohrprofil,

Fig. 4 b

die prinzipielle Darstellung der erfindungsgemäßen Verfahrensvariante nach Fig 4a für ein Flachrohrprofil,

Fig. 5

die prinzipielle Darstellung einer weiteren erfindungsgemäßen Verfahrensvariante.

Further features, advantages and advantageous embodiments of the invention will become apparent from the following description of the invention with reference to the accompanying drawings. The drawings show in:

Fig. 1

a perspective view of a hollow chamber profile according to the invention,

Fig. 2

a cross section of the hollow chamber profile according to Fig. 1 .

Fig. 3

a longitudinal section through the hollow chamber profile along section line III - III according to Fig. 1 .

Fig.4 a

the basic representation of a method variant according to the invention for a round tube profile,

Fig. 4 b

the basic representation of the method variant according to the invention Fig. 4a for a flat tube profile,

Fig. 5

the basic representation of another method variant according to the invention.

In the Fig. 1 an inventive hollow chamber profile made of metal is shown. This preferably consists of an extruded base profile 10 made of light metal. This base profile 10 has at least one aligned in the longitudinal direction of the base profile 10 channel 11, preferably a plurality of channels 11. These channels 11 are bounded by the wall 12 and by the webs 13. The base profile 10 may further have arranged on the inner sides of the wall 12 and pointing in the channels 11, parallel to the webs 13 extending web approaches, which are not shown here. Like that Figures 1 and 2 can be seen, the base profile 10 has two parallel broad sides 16, 17, which form a flat top and bottom of the profile. This is advantageous when using the profile as a heat exchanger profile. It allows easy installation and connection with the arranged on the top and bottom of the base section 10 cooling fins.

An inventive hollow chamber profile can also show the shape of a round tube or a coaxial tube and have one or more channels oriented in the longitudinal direction of the profile.

The intended to increase the heat exchange performance of the profile Verwellungen concern here only the narrow sides 18, 19 and the webs 13. The narrow sides 18, 19 are deformed perpendicular to the longitudinal orientation of the base profile, with left-facing profiles 21 and right-hand profiles 22 at the two narrow sides 18, 19 and also at the webs 13 alternate each other. As in particular from the Fig. 3 can be seen, the base profile 10 has a width B, which is the same size despite the Verwellungen at each point of the longitudinal extent. This is because the two narrow sides 18, 19 are profiled in the same way, ie have the same undulating course. Likewise, the webs 13 show the same undulating course. At every arbitrary position of the base profile 10, the distance A between two adjacent webs 13 is the same size. Also, the distance C between the narrow side 18 and the first web 13 'and the distance D between the narrow side 19 and the last web 13 "is constant, which means that any cross-section of the base profile 10 according to FIG Fig. 1 the same cross-section as in Fig. 2 shows, ie that the basic profile 10 in the longitudinal direction always has the same free flow cross-section. Accordingly, despite the swelling, there are no high pressure losses in the basic profile 10 according to the invention, since there are no impediments influencing the flow.

That in the FIGS. 1 and 3 basic profile 10 shown in an advantageous manner, a deformation of the narrow sides 18, 19 and the webs 13, which show a wave-like course in the longitudinal direction, said waves having the same wavelength. The profiles 21, 22 of the narrow sides 18, 19 and the webs 13 are in their maximum deflection, ie in their amplitudes match. Such a configuration is not mandatory for achieving a high heat exchange performance. As long as the free flow cross section remains constant, the wave-shaped course can also have different wavelengths or amplitudes. However, the above-described embodiment is easier to manufacture.

To provide an inventive hollow chamber profile made of metal with defined, reproducible Verwellungen, is in two alternative embodiments of the method according to the Fig. 4 a and 4 b and the Fig. 5 described.

• f = Oszillationsfrequenz in Hz (1/s),
• v = Strangaustrittsgeschwindigkeit in m/s,
• l = Wellenlänge in m.

In a known manner, a hollow profile strand 20 is produced by extrusion. From the extrusion press is in the Fig. 4a . 4b and 5 only the extrusion die 33 with the die chambers 34, 35 are shown. In this case, the extrusion molding device can be a direct extrusion press, indirect extrusion press or conformation press known from the prior art. The profile strand 20 having the desired profile shape is pressed out of the extrusion die 33 in the outlet direction 36. In the execution after Fig. 4a and 5 results in a round tube and in the execution Fig. 4b a flat tube profile with several channels 11. Conventionally, the hot hollow profile strand 20 along a cooling bed further processing stations, for example, for coating, forming or cutting to length, fed. At the in Fig. 4 A or 4 b shown apparatus shows the hollow profile strand 20 to a guide 37 a straight profile strand profile B I. This straight profile strand profile BI is followed by a deformed profile strand profile B II. The deformations represent left-facing profiles 21 and right-hand profilings 22, which are caused by a deformation tool 30. This deformation tool 30 moves in the displacement direction 31 to produce a left-directional profiling 21 in the hollow profile strand 20 and then to form in the direction 32 to a right-hand profiling 22. The deformation tool 30 represents an oscillator which is adapted with an oscillation frequency f adapted to the extrusion speed and thus strand exit velocity v in order to achieve a desired wavelength 1 for the hollow chamber profile 10. The oscillation frequency f of the deformation tool 30 can be set according to the following formula: $$\mathrm{f}\mathrm{=}\mathrm{v}\mathrm{/}\mathrm{1}$$

• f = oscillation frequency in Hz (1 / s),
• v = strand exit velocity in m / s,
• l = wavelength in m.

At a strand exit speed of 1 m / s (60 m / min) and a target wavelength 1 of 0.005 m (5 mm), an oscillation frequency for the deformation tool of f = 200 Hz would have to be set. The extrusion rates v for hollow chamber profiles, in particular for MP profiles (multiport profiles) or MMP profiles (Milcro multiport profiles) are 15 to 200 m / min, preferably 60 to 150 m / min. The wavelengths 1 of the wave-like deformations according to the invention are in the order of magnitude of 1 to 100 mm.

The oscillating movement of the deformation tool 30, which generates a deformation when hitting the hollow profile strand 20 due to the force, can be realized in various ways. For example, by an electric motor, by an eccentric drive or a hydraulic system.

It is also possible to deflect the hollow profile strand 30 electromagnetically.

In order to enable a low-deformation deformation, the forming temperature of the hollow section strand 20 in the forming tool 30 should be at least 250 ° C, but preferably it should be greater than 400 ° C. Is due to the construction of the entire production of the straight profile strand course BI so long that the temperature of the hollow profile strand 20 drops substantially below 250 ° C, between the outlet of the extrusion die 33 and the deformation tool 30, a heating device is provided, the hollow profile strand 20 to the desired Forming temperature in the deformation tool 30 holds. If the region of the straight profile strand profile B I is very small, such heating can be dispensed with.

In the Fig. 5 a further basic structure of a device for a method according to the invention is shown. Here has been dispensed with a separate guide 37. The deformation tool 30 also takes over the function of the strand guide of the hollow profile strand 20. In this case, however, the deflection forces generated by the deformation tool 30 by movement in the direction of displacement 31, 32, back to the die 33 and there influence the flow of material. In this case, there is no straight profiled strand profile BI after the emergence of the hollow profile strand 20 from the die 33. Since the hollow profile strand 20 is influenced into the material flow up to the forming zone, the profilings 21, 22 form directly after exiting the tool, ie already present between the die 33 and the deformation tool 30. Advantageously, the deformation tool 30 should have a width BIII in the exit direction 36, which corresponds to at least twice the wavelength 1 of the wave-shaped profiles.

Such a deformation tool 30, which constitutes an oscillating strand guide, is preferably provided on the extrusion press itself, in particular, such a deformation tool 30 can be arranged and guided in a recess in the counter-spar of the extrusion press.

LIST OF REFERENCE NUMBERS

10

basic profile

11

channel

12

wall

13,13 ', 13 "

web

14

open end of 10

15

open end of 10

16

broadside

17

broadside

18

narrow side

19

narrow side

20

Hollow profile strand

21

left-directed profiling

22

right-wing profiling

23

inner space

30

Deformation tool / oscillator

31

displacement direction

32

displacement direction

33

extrusion die

34

die chamber

35

die chamber

36

Exit direction of 20

37

guide

A

Distance between adjacent bridges

B

Width of 10

BI

straight profile strand course

BII

deformed profile strand course

BIII

Width of 30

C

Distance broadside 18 and bridge 13 '

D

Distance broadside 19 and bridge 13 "

Claims (22)

1. Hollow chamber profile made of metal, especially for heat exchangers, consisting of an extruded basic profile (10) with two wide sides (16, 17) parallel to each other and two narrow sides (18, 19), with at least one channel (11) in the inside (23) of the base profile (10) extending in the lengthwise direction of the base profile (10),
   characterized in that
   the narrow sides (18, 19) are deformed vertical to the lengthwise direction of the base profile (10), with profiles (21) left aligned transverse to the lengthwise extension, and profiles (22) right aligned transverse to the lengthwise extension, alternating with each other on both narrow sides (18, 19) and the width (B) of the base profile (10) being the same over the complete lengthwise extension of the base profile (10).
2. Hollow chamber profile according to Claim 1, characterized in that webs (13) forming several channels (11) are arranged in the inside (23) of the of the base profile (10) and extend from the wide side (16) to the narrow side (17) and that these webs (13) have profiles (21, 22) aligned vertical to the lengthwise direction of the base profile (10), with the distance (A) between two adjacent webs (13) and the distance (C) between the narrow side (18) and the first web (13') and also the distance (D) between the narrow side (19) and the last web (13" ) being the same over the complete lengthwise extension of the base profile (10).
3. Hollow chamber profile according to Claim 1 or 2, characterized in that the profiles (21, 22) of the narrow sides (18, 19) and the webs (13) have a wave-like pattern in the lengthwise extension of the base profile (10), so that the base profile (10) always has the same free flow cross-section in the lengthwise direction.
4. Hollow chamber profile according to Claim 3, characterized in that the wave-like pattern for the narrow sides (18, 19) and the webs (13) have the same length of wave over the complete lengthwise extension of the base profile (10).
5. Hollow chamber profile made of metal, especially for heat exchangers, consisting of an extruded base profile (10) in a round tube shape or coaxial shape, with, in the inside (23) the base profile (10), at least one channel (11) extending in the lengthwise direction of the base profile (10),
   characterized in that
   opposite sides of the base profile (10) are deformed vertically relative to the lengthwise direction of the base profile (10), with profiles left-aligned (21) transverse to the lengthwise extension and profiles (22) right-aligned transverse to the lengthwise extension alternating with each other on the sides and the width (B) of the base profile (10) being the same over the complete lengthwise extension of the base profile (10).
6. Hollow chamber profile according to one of Claims 1 to 5, characterized in that the base profile (10) is made of aluminium or an aluminium alloy.
7. Hollow chamber profile in accordance with one of Claims 1 to 6, characterized in that it is used as a cooler for gas or liquid flows, especially as a gas cooler or charge-air cooler for motor vehicles.
8. Method for manufacturing a hollow chamber profile made of metal, especially for a heat exchanger,
   with a hollow profile extrusion (20) in round-tube form or coaxial form or a hollow profile extrusion (20) with two parallel wide sides (16, 17) and two curved or flat narrow sides (18, 19) and at least one channel (11) extending in the inside (23) of the base profile (10) being produced by extrusion,
   this hollow profile extrusion (20) being deformed and
   the profile extrusion then being cut to the required length of a base profile (10),
   characterized in that
   the hot profile extrusion (20) emerging from the deforming zone of the extrusion matrix (33) is set in a defined oscillation and/or deformed by an oscillating, moving deforming tool (30).
9. Method according to Claim 8, characterized in that a hollow profile extrusion is extruded from aluminium or aluminium alloy.
10. Method according to Claim 8 or 9, characterized in that profiling (21, 22) of equal thickness of the narrow sides (18, 19), and any webs (13) present, is simultaneously carried out on the hot profile extrusion, (20) emerging directly from the deforming zone, by means of a moving deforming tool (30) oscillating vertically relative to the direction of emergence (36) of the profile extrusion (20).
11. Method according to Claim 10, characterized in that the narrow sides (18, 19) and the webs (13) receive equal wave-like deformation in the lengthwise direction of the base profile (10).
12. Method in accordance with Claim 8 or 9, characterized in that circular wave-like shapes are formed in the profile walls (12) on the hot hollow profile extrusion (20) immediately it emerges from the deforming zone, by means of the deforming tool (30) moving in two planes of oscillation.
13. Method in accordance with Claims 8 to 11, characterized in that to achieve the required length of wave (1) of the wave-like deformation, the frequency of oscillation (f) of the deforming tool (30) is matched to the speed (v) of emergence of the extrusion.
14. Method according to one of claims 8 to 13, characterized in that the profile extrusion is generated at extrusion speeds (v) of 15 to 200 m/min, preferably at 60 to 150 m/min.
15. Method according to one of Claims 8 to 14, characterized in that the length of the waves of the wave-like deformations of the profile extrusion (20) is in the order of 1 to 100 mm.
16. Method in accordance with one of Claims 8 to 15, characterized in that the deforming tool (30) grips the hot hollow profile extrusion (20) immediately it emerges from the extrusion matrix (33), so that the deflection forces occurring during the oscillating movement of the deforming tool act back directly on the extrusion matrix (33).
17. Method according to Claim 16, characterized in that the deforming tool (30) is arranged in a recess in the reaction post of the extrusion press.
18. Method in accordance with one of Claims 8 to 15, characterized in that the hollow profile extrusion (20) emerging from the extrusion press is immediately gripped by a guide (37), arranged at a distance from the extrusion matrix (33), and fed to a deforming tool (30), with the temperature of the hollow profile extrusion (20) reducing during the process from the exit temperature at the extrusion matrix (33), to a deformation temperature of at least 250°C, preferably to greater than 400°C, within the deforming tool (30).
19. Method according to one of Claims 8 to 15, characterized in that the hollow profile extrusion (20) emerging from the extrusion press is immediately gripped by a guide (37), arranged at a distance from the extrusion matrix (33), and is heated to a deforming temperature of at least 250°C, preferably to greater than 400°C, before being fed to a deforming tool (30).
20. Method according to one of Claims 8 to 19, characterized in that the oscillating movement of the deforming tool (30) is electromagnetically generated.
21. Method according to one of Claims 8 to 19, characterized in that a fluid medium is cyclically applied to the deforming tool (30) to achieve the deformation of the hollow profile extrusion (20).
22. Method according to Claim 8, characterized in that the extrusion press matrix (33) itself acts as an oscillating, moving deforming tool (30).

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