Flat Tube for a Heat Exchanger
The invention relates to a multi-channel flat tube (1) for a heat exchanger, especially for use in motor vehicles, which comprises a first lateral wall (14), a second lateral wall (15) substantially parallel to the first lateral wall (14), and at least one curved end section (17). A projection (9) from the material of the lateral wall (14, 15) is configured on at least one lateral wall (14, 15) on the inside facing a fluid flow in the interior of the flat tube (1). On the outside facing away from the fluid, the lateral wall (14, 15) is substantially planar in the area of the projection (9).
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The present invention relates to a flat tube for a heat exchanger, in particular for a motor vehicle. According to the prior art, heat exchangers in motor vehicles, for example in automotive air conditioning systems, exhibit, in addition to collecting arrangements for a coolant, flat tubes that are provided for the purpose of the onward conveyance of the coolant and/or other fluids.
These flat tubes are connected in this case to the collecting arrangements via tube bases or the like. Particular importance must also be attached to the sealing in this connection.
The flat tubes previously disclosed according to the prior art exhibit ribs and/or projecting parts in their interior, the effect of which is for the flat tube as a whole to be of multi-channel execution.
The ribs previously disclosed according to the prior art consist of beads formed on both sides or ribs formed on one side. The flat tubes in this case do not, however, exhibit a closed and/or a smooth profile on their outside in the area of the ribs. The effect of this non-smooth external profile of the flat tubes is the need to incur a greater process expenditure in conjunction with the insertion of the flat tubes into the bases, in order to achieve a fluid-tight connection. Furthermore, according to the prior art, the ribs on the outside are not adequately closed, so that leaks arise in the connection between the tube and the base in the remaining external tube cavities. A remaining channel on the outside of the flat tube can also be the cause of failure in conjunction with soldering. In addition, according to the prior art, the external tube cavities occurring in the areas of the ribs must be recalibrated at the ends of the tubes after manufacture of the tubes, in order to achieve externally smooth tubes.
EP 0 854 343 illustrates flat tubes of this kind, which exhibit considerable external cavities on their outside, and these are reduced in size by an expensive process.
The object of the present invention is thus to make available a flat tube, which exhibits projecting parts in its interior and, at the same time, largely avoids depressions or recesses on its outside in the area of the projecting parts.
This is achieved according to the invention by a flat tube according to claim 1 and by a process for its manufacture according to claim 12. Preferred further developments of the flat tube and the process are the subject-matter of the dependent claims.
The multi-channel flat tube according to the invention for a heat exchanger, in particular for a motor vehicle, exhibits a first longitudinal wall, a second longitudinal wall, which lies substantially parallel to the first longitudinal wall, and at least one curved end section. In conjunction with this, a projecting part is configured on at least one longitudinal wall from the material of the longitudinal wall on the inside facing a fluid flow in the interior of the flat tube. According to the invention, the longitudinal wall is essentially level on its outside facing away from the fluid in the area of the projecting part.
The expression “multi-channel tube” is understood to denote that a plurality of channels that are essentially mutually separate from one another is configured in the inside of the tube. The expression “flat tube” is understood to denote a tube that is configured in its cross section in such a way that this exceeds one direction of extension by a good margin in a second direction of extension.
The expression “a longitudinal wall of the flat tube” is understood to denote the wall which runs along one of the longitudinal sides. The expression “a projecting part configured from the material of the longitudinal wall” is understood to denote a projecting part of a kind that is not subsequently applied to the wall, but—in particular, although not exclusively—is configured from the wall itself by a forming process.
The expression “in the area of the projecting part” is understood to denote the geometrical area of the corresponding longitudinal wall in which the projecting part is configured. The expression “essentially level” is understood to denote that the external profile in the area of the projecting parts does not exhibit any depressions, or that it only exhibits depressions with a small cross-sectional area.
In a further preferred embodiment, the projecting part is in contact with the second longitudinal wall, which means that the projecting part is configured on one longitudinal wall and makes contact with the opposing longitudinal wall. In this way, channels that are essentially separated from one another can be provided inside the flat tube.
In a further preferred embodiment, the flat tube exhibits two curved end sections. At least one end section is preferably bent through at least 180 degrees, in order to cause the two longitudinal walls to be arranged essentially parallel in relation to one another. The second end section can also be bent in some other way, in order to close the flat tube; for example, each of the end areas of the basic material can be bent partially about a given angle in the course of the manufacturing process before being joined together at this point.
In a further preferred embodiment, a plurality of projecting parts is configured from the material of the longitudinal wall on a longitudinal wall.
In a further preferred embodiment, projecting parts are configured on both longitudinal walls from the material of the longitudinal walls. In this case, in a further preferred embodiment, all the projecting parts make contact with the opposing longitudinal wall in each case. It is possible in this way to achieve a situation in which the flat tube, in the manufactured state, is configured with a plurality of chambers that are essentially separated in relation to one another.
In this case, the distances between the projecting parts can be selected in such a way that the finished flat tube exhibits channels with an essentially constant cross-sectional area.
In a further preferred embodiment, it is also possible to configure the projecting parts so that they do not make contact with the opposing longitudinal wall, but with a further projecting part arranged on the opposing longitudinal wall.
In a further preferred embodiment, at least one projecting part, preferably a plurality of projecting parts, and especially preferred all the projecting parts, exhibits an essentially symmetrical profile. This means that the projecting part exhibits an axis of symmetry running essentially perpendicular to the plane of the longitudinal wall, in relation to which the projecting part is of essentially axially symmetrical configuration.
In a further preferred embodiment, the flat tubes exhibit a depth between 0.5 mm and 5 mm, preferably between 0.8 mm and 4 mm, and especially preferred between 1 mm and 3 mm. Each of these depths depends on the actual applications in the heat exchangers to be manufactured.
In a further preferred embodiment, at least one wall exhibits a wall thickness between 0.05 mm and 0.8 mm, preferably between 0.07 mm and 0.6 mm and—especially preferred—between 0.1 mm and 0.5 mm. The corresponding projecting parts are preferably adapted depending on this wall thickness, in which case account must also be taken in particular of process engineering requirements.
The present invention also relates to a process for the manufacture of a multi-channel flat tube for a heat exchanger. In this case, a projecting part with a predetermined profile is produced in one process stage from a strip of material by means of a first forming unit and a second forming unit acting together with the first forming unit.
In a further process stage, the profile of the projecting part is modified by means of a third forming unit and a fourth forming unit acting together with the third forming unit.
The expression “modification of the profile” is understood to denote that predetermined geometrical modifications are made to the projecting part and/or its cross section.
The expression “forming unit” is understood to denote an arrangement which acts on the material to be processed in such a way that it is modified, at least locally.
The forming units in question are preferably rollers that are capable of rotating in relation to one another. The first and the second forming units are thus embodied preferably as contra-rotating upper and lower rollers, between which the material to be processed is arranged. In the case of the third and fourth forming units, too, the units in question are corresponding rollers, between which the material to be processed is arranged. The rollers are preferably embodied in such a way that one roller is limited by lateral edges of the other roller, in order in this way to prevent broadening of the strip of material to be worked in the course of the forming process.
In a further preferred embodiment, the rollers exhibit an essentially cylindrical profile.
It would also be possible, however, instead of rollers, to provide two opposing supports, between which the material is pressed and/or pulled.
The change in the profile in at least one process stage preferably involves a reduction in its height and/or width. Preferably both the height and the width of the projecting part are reduced in the course of this process stage. It is possible in this way to achieve the situation in which the outside of the flat tube is made level in the area of the projecting part, which means that a depression is reduced in this area.
The profile of the projecting part is preferably further modified in at least one further process stage. In this case, the height and/or the width of the profile is preferably reduced in turn. Preferably a number of consecutive process stages is provided, in which the profile of the projecting part is continually modified, in conjunction with which this modification in each case involves at least the reduction of the width or the height of the profile. These process stages serve the purpose in each case—as mentioned above—of achieving the greatest possible levelness of the external surface of the flat tube profile in the area of the projecting part.
The profile of the projecting part is modified preferably in at least four process stages, and especially preferred in at least six process stages. Too few process stages would lead to the risk of the material to be processed not being able to withstand the necessary extensive reshaping, possibly resulting in cracking and the like. The number of process stages is restricted in the upward direction by the required efficiency, both in terms of the manufacturing costs and in terms of the time input.
In a further preferred process, pre-centering of the projecting part is undertaken in a further process stage. This is achieved preferably by means of a pre-drawing operation.
The rotating rollers, through which the material is passed, preferably exhibit an essentially constant distance in relation to one another. The situation in which the material for processing exhibits an essentially constant wall thickness and/or gauge is achieved in this way. The material of the roller is preferably matched to the material for processing in such a way that the diffusion of material particles is prevented.
The width of the strip of material is preferably reduced in at least one process stage. The material is supplied to the rollers in the form of strips with predetermined dimensions. The expression “width of the strip of material” is understood to denote its extension in the direction of the axis of the roller. By adopting this procedure, it is possible to achieve the configuration of the projecting part in a particularly advantageous manner in each case. In a further preferred embodiment, the width of the strip of material remains constant in at least one process stage. In these process stages, a modification of the form of the projecting part is achieved essentially without the use of further material from the area surrounding the projecting part.
A plurality of projecting parts is preferably formed from the strip of material. For this purpose, the required quantity of additional material can preferably be obtained by reducing the length of the strip in a first process stage.
The projecting parts in this case are preferably configured at predetermined distances in relation to one another. The projecting parts are preferably selected in such a way that the flat tube produced in this way essentially exhibits a plurality of channels of essentially identical cross section.
Different projecting parts are preferably subjected to different forming steps in at least one process stage. The intention in this case is for a particular projecting part to be adapted already in respect of its form, whereas a further projecting part is only formed or a projecting part already receives its final form, whereas a further projecting part is still adapted in respect of its form in an intermediate stage.
Under certain circumstances, it is possible in this way to arrive at the situation in which a plurality of projecting parts are manufactured with a small number of reshaping stages in such a way that preformed projecting parts or projecting parts that have already been formed in advance are not adapted further in respect of their shape.
A curved section is preferably produced in a further process stage. A curve of 180 degrees is preferably produced in order to arrange the longitudinal walls in this way so that they lie essentially parallel in relation to one another.
Further advantages and embodiments can be appreciated from the accompanying drawings.
In the drawings:
The individual process stages of a process according to the invention for the production of a projecting part are depicted in
Attention is drawn to the fact that the process depicted in
The reference designation L designates the center line, and preferably the axis of symmetry of the produced projecting part 9a to 9f. In the optional process stage 1a, pre-centering of the projecting part 9a is undertaken by means of a pre-drawing operation. This is particularly advantageous if the projecting parts and/or the ribs need to be produced with large heights HA to HF.
In process stage 2, the strip of material and/or the strip 7 is reshaped in the indicated area Z. For this purpose, the forming units in each case, that is to say preferably the rollers, exhibit a bead-like form. The overall width b of the strip 7 is produced by the production of the projecting part 9b in process stage 2, in conjunction with which the overall width b is smaller than the overall width a, and respectively the overall width a′ in process stages 1 and 1a.
The height HB produced in process stage 2 represents the maximum height Hmax of the projecting part 9b, which is reduced even further, at least in part, in the course of further process stages.
In stages 2 to 6, the development of the neutral fiber in the area Z remains almost constant. This means that, in the area Z, essentially the same quantity of material is always supplied respectively to the forming units and to the rollers. This is achieved through a corresponding design of the forming stages in each case in steps 2 to 6 by retaining the overall widths of the strips in each case.
The widths of the strips b to f thus remain essentially constant in process stages 2 to 6. In order to keep the overall strip widths b to f constant, the strip of material 7 is preferably retained with suitable tools at each of the end points B to F.
Essentially only one reshaping of the projecting part 9 thus takes place during process stages 2 to 6. In particular, both the height H and the width of the projecting part 9 decrease, and the flanks 25 in each case follow a steeper path. The radius of curvature at the tip of the projecting part 9a to 9f in each case is reduced in the course of the process. This means that the material that is economized by a reduction in the height and the width is essentially added by the fact that the surface of the depression 11 is constantly reduced underneath the projecting part.
To put it another way, the width of the strip between the starting point 33 and the end point 34 preferably remains essentially constant during process stages 2 to 6. During process stages 5 and 6, a closure of the projecting part and/or the depression 11 must be achieved underneath the projecting part 9, which means that the flanks 29 of the projecting part are pressed against one another in each case. For this purpose, the material 7 in the area of the projecting part is enclosed essentially completely by the corresponding areas of the forming units.
Alternatively, in process stage 5, the projecting part that is still open in process stage 4 can also be closed by folding together, gathering or pinching. The height HD and/or HE will not be significantly reduced in a procedure of this kind, however, but rather the overall width of the strip. In this case, steps would also have to be taken to counteract the danger of scratching between the pinching tools, in addition to which no ideally reduced rib external cavity 11 will also be obtained.
It is also possible to permit a change in the width of the strip in the area Z, moreover, in at least one of the process stages 3 to 6, which means that the width of the strip b to f will also not remain constant, at least in part, in the process stages 3 to 6. If this variant procedure is adopted, material and/or strip material can flow back into the width of the strip in conjunction with compression of the projecting part, that is to say from the area of the projecting part.
One possible consequence is that too little material will be available to close the external cavity 11 in subsequent process stages, or that more material will need to be pre-drawn in the first stages. In this case, increased thinning of the strip of material 7 and a greater risk of cracking can also occur. The necessary rib height cannot be achieved under certain circumstances, furthermore, and the process will become more sensitive overall in relation to fluctuations in the characteristics of the strip material.
A final height HF, which is smaller than the height HE in process stage 5, is achieved in process stage 6 depicted here. At the same time, the area 11, which is still present in process stage 5, is essentially closed, and the smooth outer profile according to the invention is accordingly achieved.
The strip width and/or the overall width of the strip e is also not reduced any further, which means that the strip width f and the strip width e are essentially the same.
The depression 26 and the processing projecting part 25 are adapted to one another in such a way that the material can be passed between them with a predetermined gauge and/or thickness S.
Gaps 13a and 13b are provided between the upper roller 21 and the lower roller 22. During the first process stage, material from the strip continues to be drawn into the area of the upper roller.
The strip of material and/or the strip runs against the lower roller during compression. In conjunction with this, the widths of the strip must accordingly be kept essentially constant and/or as constant as possible, as soon as the height HB according to
The arrangement for process stage 6 represented in
In addition to the process stage depicted in
In a first optional stage I, a cavity 31 is produced by means of suitably adapted upper and lower rollers, that is to say rollers which exhibit a processing projecting part and a depression, as depicted in
Two projecting parts 9a and 9b are produced in process stage II. An upper roller with a corresponding depression and a lower roller with an appropriately adapted processing projecting part are preferably used for this purpose. It is also possible, however, to utilize a lower roller without a processing projecting part in this process stage.
The width of the strip is reduced from a strip width a in process stage I, to a strip width b in process stage II, and to a strip width c in process stage III. It is also possible, however, to undertake only a reshaping of the projecting parts 9 in process stage III, which in this case means keeping the strip width c essentially constant in relation to the strip width b.
In process stage IV, two further projections 9c and 9d are produced by appropriately adapted upper and lower rollers. For this purpose, the strip width c in process stage III is reduced to the strip width d in process stage IV. The lower roller preferably exhibits processing projecting parts for this purpose in the area of the new projecting parts to be produced.
The projecting parts lying further to the inside and then the projecting parts lying further to the outside are preferably produced initially in conjunction with the production of the projecting parts. This is advantageous because it permits material from the outer areas of the strip of material to be used in each case to produce the new projecting parts, and it prevents material from the areas of other, already produced projecting parts from being drawn in. It is also possible, however, to provide and/or to produce a plurality of projecting parts in place of the projecting part depicted here. The process stages depicted in
The reshaping of the individual projecting parts already depicted in
Process stage IV can also be supplemented by further process stages, in order to produce additional projecting parts and/or ribs.
Depicted in
By further forming processes, for example cold roll forming, the projecting parts 9a to 9d can be arranged in such a way that they make contact with the opposing wall in each case (the wall 15 in the case of the projecting parts 9b and 9d, and the wall 14 in the case of the projecting parts 9a and 9c).
The projecting parts 9a to 9d and/or their end areas are preferably soldered to the opposing longitudinal wall in each case. The two bent end areas 18 and 19 are similarly soldered to one another in such a way as to provide a tight joint. A flat tube with five channels in total is achieved by producing the four projecting parts 9a to 9d depicted here.
Process stages I to VIII for producing a flat tube with an odd number of projecting parts, in this case more specifically three projecting parts, are represented in
A projecting part 9a is produced in process stage II—similar to that produced in process stage II in
Two further projecting parts 9b and 9c are produced in process stage IV. The production of the individual projecting parts 9a and respectively 9b and 9c is transposed in this process, which means that, whereas the first reshaping operation has already taken place in the case of the projecting part 9a, sections 9b and 9c were produced first in this instance. The strip width d in this case is further reduced in relation to the strip width c. In this variant, too, the internal projecting parts are preferably formed initially, followed by the external projecting parts.
The three projecting parts 9a, 9b and 9c are subjected to further forming in process stage V. The width of the strip remains largely constant here, that is to say the strip width e essentially corresponds to the strip width d.
A further reshaping process of the kind described above takes place in process stage VI, that is to say the height of the individual projecting parts 9a, 9b and 9c is reduced, as is their width; the flanks are of a steeper execution for this purpose, and the radii of curvature at the tip of the projecting parts are accordingly smaller.
The width of the projecting parts is reduced even further in a further process stage VII, before being closed finally in process stage VIII. The individual strip widths e, f, g and h essentially remain constant in conjunction with this. Corner folds 42a and 42b are formed by bending in the final process stage following process stage VIII. These two corner folds result in the production of a further projecting part, and corner folds are in fact capable of being produced in several process stages.
Depicted in
In this embodiment, too, the individual projecting parts 9a to 9c and the projecting part produced by the end folds 42a and 42b make contact with the opposing longitudinal wall of the flat tube in each case. A flat tube with five channels is produced in this embodiment, too. The process (process stages I-VIII) illustrated in
Illustrated in
Reference designation a relates to the distance of the ribs along a longitudinal wall. Reference designation K denotes the distance between two neighboring ribs, which under certain circumstances form a chamber. Reference designation T denotes the thickness of the flat tube.
In the embodiment illustrated here, the thickness T preferably lies between 1 mm and 3 mm. The chamber and/or the size of the channel has been selected here so that it is about half as large as the distance between the ribs a (distance of the projecting parts). The minimum distance between the ribs in this embodiment is at least twice as large as the width T. The minimum chamber size and/or channel size is accordingly at least as large as, or larger than the thickness T.
In the embodiment shown in
In the embodiment depicted in
In a further embodiment (not illustrated here), it is also conceivable to execute the individual projecting parts in such a way that—unlike the embodiment depicted in
In
The boundaries indicated below are the result of extensive soldering and reshaping trials. In the course of these trials, the parameters were matched to one another according to a predetermined system, and the results were utilized for the boundaries represented here.
The upper radius of curvature rf in this embodiment lies between 0 and the wall thickness t, that is to say it is smaller than the wall thickness t. The lower radius of curvature RF is smaller than twice the wall thickness t. The upper width X of the projecting part lies between one-and-a-half times and two times the wall thickness t. The lower width Y of the projecting part lies between two times and two-and-a-half times the wall thickness t, which means that the upper width X is smaller than the lower width Y, which is also the outcome of the forming process.
The height of the projecting part HF lies between the wall thickness t and ten times this wall thickness t. The lower radius of the depression rD is also smaller than the wall thickness t. The wall thickness t lies between 0.05 mm and 0.8 mm, preferably between 0.1 mm and 0.7 mm, and especially preferred between 0.1 mm and 0.5 mm. This means that the expression “an essentially smooth external profile” is understood to denote a profile of the kind which is produced by radii of curvature rD that are smaller than the wall thickness t.
The proportion of the tube width b to the tube height H lies between 10 and 30, and preferably between 10 and 24.
The size of the chamber and/or the size of the channel lies between one third of the width of the tube and one half of the width of the tube.
The height of the projecting part hF preferably lies between three times the wall thickness and eight times the wall thickness. The lower radius of curvature rd is found to be less than 0.75 times, and preferably smaller than or equal to 0.5 times the wall thickness t. In this embodiment, the wall thickness lies between 0.05 mm and 0.6 mm, preferably between 0.1 mm and 0.4 mm, and especially preferred between 0.15 mm and 0.3 mm. In conjunction with this, a depression 11 remains on the outside of the flat tube, which exhibits a surface area of less than 0.01 mm2, and preferably of less than 0.006 mm2. This represents a considerable improvement compared with the prior art.
The depression 11 illustrated in
Thanks to this considerable reduction in the surface area of the depression 11, the flat tube, as mentioned by way of introduction, can be soldered far more easily to the base of the tube, and a tight connection can be achieved at far lower cost.
Claims
1. A multi-channel flat tube for a heat exchanger, in particular for a motor vehicle, having a first longitudinal wall, a second longitudinal wall, which lies substantially parallel to the first longitudinal wall, and at least one curved end section, in conjunction with which a projecting part is configured on at least one longitudinal wall from the material of the longitudinal wall on the inside facing a fluid flow in the interior of the flat tube, wherein the longitudinal wall is essentially level on its outside facing away from the fluid in the area of the projecting part.
2. The flat tube as claimed in claim 1, wherein the projecting part configured on a longitudinal wall is in contact with the second longitudinal wall.
3. The flat tube as claimed in claim 1, wherein it exhibits two curved end sections.
4. The flat tube as claimed in claim 1, wherein a plurality of projecting parts is configured on a longitudinal wall from the material of the longitudinal wall.
5. The flat tube as claimed in claim 1, wherein projecting parts are configured on both longitudinal walls from the material of the longitudinal walls.
6. The flat tube as claimed in claim 1, wherein a plurality of projecting parts, and preferably all the projecting parts, make contact with the opposing longitudinal wall in each case.
7. The flat tube as claimed in claim 1, wherein at least one projecting part on one longitudinal wall makes contact with a projecting part on the opposing longitudinal wall.
8. The flat tube as claimed in claim 1, wherein at least one projecting part exhibits an essentially symmetrical profile.
9. The flat tube as claimed in claim 1, wherein the flat tube exhibits a depth between 0.5 mm and 5 mm, preferably between 0.8 mm and 4 mm, and especially preferred between 1 mm and 3 mm.
10. The flat tube as claimed in claim 1, wherein at least one projecting part exhibits a height HF between three times and eight times a wall thickness of the flat tube, and in particular between four times and six times a wall thickness of the flat tube.
11. The flat tube as claimed in claim 1, wherein at least one wall and preferably the whole of the flat tube exhibits a wall thickness between 0.05 mm and 0.8 mm, preferably between 0.07 mm and 0.6 mm and especially preferred between 0.1 mm and 0.5 mm.
12. The flat tube as claimed in claim 1, wherein at least one projecting part exhibits a depression with a radius of curvature rD, which is smaller than or equal to a wall thickness of the flat tube, and is preferably smaller than or equal to 75% of a wall thickness of the flat tube.
13. A device for the exchange of heat having at least one flat tube as claimed in claim 1.
14. A process for the manufacture of a multi-channel flat tube for a heat exchanger with the following process stages:
- Production of a projecting part with a predetermined profile from a strip of material by means of a first forming unit and a second forming unit acting together with the first forming unit;
- Modification of the profile of the projecting part by means of a third forming unit and a fourth forming unit acting together with the third forming unit.
15. The process as claimed in claim 12, wherein the forming units are rollers that are capable of rotating in relation to one another.
16. The process as claimed in claim 1, wherein, in conjunction with the modification of the profile of the projecting part, its height and/or width is reduced.
17. The process as claimed in claim 1, wherein the profile of the projecting part is further modified in at least one further process stage.
18. The process as claimed in claim 1, wherein the profile of the projecting part is modified in at least four, and preferably in at least six process stages.
19. The process as claimed in claim 1, wherein pre-centering of the projecting part is undertaken in a process stage.
20. The process as claimed in claim 1, wherein the rotating rollers exhibit axes of rotation that are parallel to one another.
21. The process as claimed in claim 1, wherein the width of the material strip is reduced in at least one process stage.
22. The process as claimed in claim 1, wherein the width of the material strip remains essentially constant, and in particular remains constant, in at least one process stage.
23. The process as claimed in claim 1, wherein a plurality of projecting parts is configured from the material strip.
24. The process as claimed in claim 1, wherein the projecting parts are configured at predetermined distances in relation to one another.
25. The process as claimed in claim 1, wherein the projecting parts are subjected to different forming steps in at least one process stage.
26. The process as claimed in claim 1, wherein a curved section is produced in a further process stage.
Type: Application
Filed: Oct 11, 2005
Publication Date: Dec 27, 2007
Applicant: BEHR GMBH & CO. KG (70469 Stuttgart)
Inventor: Jurgen Haegele (Stuttgart)
Application Number: 11/664,993
International Classification: F28F 1/02 (20060101); B21D 53/02 (20060101);