FIELD OF THE INVENTION The present invention relates to a method for producing a channel arrangement. The method comprises the steps a) arranging a first metal profile towards a second metal profile, said first metal profile comprises elongated trench-like portions mutually separated by flat portions, and b) joining the first metal profile to the second metal profile so that channels between these profiles are defined, which channels extend according to said trench-like portions, said channels being separated by flat regions.

Furthermore, the present invention relates to a channel ar- rangement, use of a channel arrangement and a metal profile.

PRIOR ART

A channel arrangement in here defined to comprise two or more channels separated by flat regions. The channel arrangement comprises preferably a material with high thermal conductivity, such as copper, aluminum, etcetera, wherein the flat regions are adapted to conduct heat to or from the channels. The channels are adapted to conduct a fluid, such as a cooling medium or a heat medium. Accordingly, the channel arrangement is adapted to absorb heat or radiate heat.

Such channel arrangements are used as heat exchangers in various technical applications, such as heat radiators in en- gines, computers, etcetera, and heat absorbers, such as in solar absorbers, etcetera. The channels must have a material thickness that provides sufficient strength to maintain a certain pressure of the fluid within the channels. The flat regions between the channeis must have a thickness that provides sufficient heat conduction rate to or from the channels. In most situations the desired pressure of the fluid within the channeis requires a higher material thickness than the necessary material thickness of the flat regions. Accordingly, a channel arrangement configured with higher material thickness of the channeis than the material thickness of the f!at regions provides a reduced material consumption for the channel arrangement with negligible reduction in performance when used in a heat exchanger. Furthermore, such channel ar- rangement has reduced weight. in order to produce channel arrangement with complex geometry, such as channel arrangement where the material thickness of the channels is higher than the material thickness of the flat regions, extrusion is used. However, extrusion of channel arrangement is only possible for certain metals. For example, copper and copper alloys are difficult to extrude. Furthermore, the production rate by extruding channel arrangement may be insufficiently low for some metals. in order to facilitate the manufacturing of channel arrangements of various types of metals a first metai profile and a second metal profile are used. The metai profiles are joined together by various joining methods, such as welding, rolling, etcetera.

A problem with manufacturing channel arrangement from the first and the second metal profile is that the material thickness of the channels is the same as the material thickness of the flat regions. Thereby, the channel arrangement is not using the ma- terial of the metal profiles optimally, which adds cost and weight to the channel arrangement. EP1894660 discloses a method for manufacturing a channel arrangement by means of clad-roliing a first metal profile towards a second metal profile. Although their method is favorable and reliable, the manufactured channel arrangement is configured so that the material thickness of the channels is the same as the material thickness of the flat regions.

OBJECTS AND SUMMARY OF THE INVENTION

The object of the present invention is to provide a method for producing a channel arrangement being improved in at least some aspect with respect to such methods already known. The object of the present invention is furthermore to provide an im- proved channel arrangement, use of the channel arrangement and an improved metal profile adapted to be manufactured into a channel arrangement.

This object is obtained by a method as defined by the preamble of claim 1 , wherein the method is characterized by using in step a) as at least one of said profiles a profile comprising an incipient cut to be located in at least one said flat region, and by comprising a further step c) carried out after step b) of removing material from said at least one flat region by means of said in- cipient cut, so that the thickness of at least a part of said at least one fiat region becomes less than the sum of the thicknesses of the first and the second metal profile.

The incipient cut is adapted to enable a removal of the material from said at least one flat region. Thereby, the materia! thickness of said at least one flat region is reduced while the material thickness of the channels are maintained. Accordingly, the method enables a channel arrangement to be produced with reduced material consumption. Furthermore, the weight of the manufactured channel arrangement is reduced. The term "incipient cut" refers to an arranged weakening in the strength of the material of the meta! profile as compared with the strength of the remaining pari of the metal profile. Thereby, the incipient cut is adapted to enable materia! to be removed from the at least one fiat region.

According to one embodiment of the invention, said incipient cut at least partly encloses the material to be removed. Thereby enabling the at least partly encloses the material to be removed.

According to one embodiment of the invention, said incipient cut extends along one of the elongated trench-like portions. Thereby, a large part of said at least one flat region is adapted to be removed.

According to one embodiment of the invention, said incipient cut forms at least one loop, wherein materia! located within the loop is adapted to be removed by means of the incipient cut. By means of the loop formed incipient cut a part of the material be- tween a first side and a second side of the meta! profile may be removed. Furthermore, the loop formed incipient cut may be arranged in a complex form that forms a complex remaining pattern on said at least one flat region. According to one embodiment of the invention, the loop formed incipient cut is arranged to form a recession in the at feast one fiat region, which recession is arranged to accommodate the reception a fin structure for absorbing or radiate heat. The recession facilitates positioning of the fin structure on said at least one flat region.

According to one embodiment of the invention, said incipient cut intrudes a certain depth into the thickness of on of the first and the second metal profile, which depth is less than the thickness of the one of the first and the second metal profile along which the incipient cut extends. The intruding depth of the incipient cut is arranged so that the metal profile with the incipient cut is allowed to be handled and joined towards another metal profile without that the material at the incipient cut breaks and forms an edge.

According to one embodiment of the invention, said incipient cut intrudes from a top side and a lower side into the thickness of one of the first and the second metal profile. According to one embodiment of the invention, an intruding part of the incipient cut, which intruding part intrudes the certain depth into the thickness of one of the first and the second metal profile, is provided intermittent along the extent of said incipient cut.

According to one embodiment of the invention, said intruding part intrudes fully through the thickness of one of the first and the second metal profile, wherein the intruding part is provided intermittent along the extent of said incipient cut.

According to one embodiment of the invention, the step c) comprises gripping a part of the material to be removed and pulling that part of the materia! in a direction along which the incipient cut extends. Accordingly, the incipient cut is adapted to allow the material at the incipient cut to break and form an edge when the material to be removed is being pulled.

According to one embodiment of the invention, said incipient cut is arranged on one of the first and the second metal profile.

According to one embodiment of the invention, wherein the first metal profile is joined to the second metal profile while forming a plurality of joints in said flat regions and said at least one flat region comprises a first joint adjacent to one of two adjacent channels and a second joint adjacent to the other of the two channels, wherein said incipient cut is adapted to be located be- tween the first and the second joint. Accordingly, the incipient cut is arranged so that first and the second joint is maintained unaffected when removing the material from the at least one f!at region.

According to one embodiment of the invention, the the incipient cut is arranged at a distance from the first and the second joint so that the integrity of the joints are maintained when removing the material from the at least one flat region.

According to one embodiment of the invention, wherein the joining of the first metal profile to the second metal profile comprises ciad-roiiing the flat portions of the first metal profile towards the second metal profile. By means of clad-ro!ling the metal profiles are joined together in an efficient and cost- effective manner.

According to one embodiment of the invention, wherein the second metal profile comprises a flat portion adapted to form said flat region.

According to one embodiment of the invention, wherein the second metal profile has a form corresponding to that of the first meta! profile. The expression "a form corresponding to" refers to that the form of the second metal profile is substantially the same as the form of the first metal profile, and regardless if the second profile is provided with the incipient cut or not.

The object is further obtained by a channel arrangement accord- ing to the preamble of claim 1 1 . The channel arrangement is characterized in that at least a part of one said flat region of the channel arrangement has a thickness being less than the sum of the thicknesses of the first and second metal profile by having material removed from one of the profiles on that location. Thereby, the material consumption and the weight of the channel arrangement are reduced in comparison to prior art channel arrangement.

According to one embodiment of the invention, said one flat region comprises a first joint adjacent to one of two adjacent channels and a second joint adjacent to the other of the two channels, wherein the arrangement comprises an edge between the first and the second joint, which edge was formed when removing material located at least partly enclosed by an incipient cut.

According to one embodiment of the invention, the first and the second metai profiie consist of metal with high thermal conductivity. Preferably, the first and the second metal profile consist of copper or aluminum, or alloys thereof. By means of using a metai with high thermal conductivity in the metai profiles the heat conduction rate between the channels and the flat regions are high, which improves the efficiency when the channel arrangement is used in a heat exchanger. According to one embodiment of the invention, the first and the second metal profile is adapted to form channels with circular cross section. The circular cross section of the channels enables a high pressure of the fluid to be conducted therein. According to one embodiment of the invention, the material thickness of each of the first and the second metal profiie is less than 1 mm, preferably less than 0,7 mm.

According to one embodiment of the invention, the material thickness of each of the first and the second metal profiie is more than 0,3 mm, preferably more than 0,5 mm.

According to one embodiment of the invention, the first and the second metai profile is adapted to form channels with a cross section of less than 10 mm ² , preferably less than 7 mm ² . According to one embodiment of the invention, the first and the second metal profile is adapted to form channels with a cross section of more than 3 mm ² , preferably more than 5 mm ² . The object is further obtained by the use of a channel arrangement for conducting fluid in said channels thereof. According to one embodiment of the invention, the channel arrangement is used in a solar absorber. The object is further obtained by a metal profile according to the preamble of claim 15, wherein one of said metal profiles comprises an incipient cut in at least one said fiat portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained more closely by the description of different embodiments of the invention and with reference to the appended figures. Fig. 1 a shows a metal profile comprising two incipient cuts.

Fig. 1 b shows a detail view of the incipient cut in the encircled area of fig. 1 a.

Fig. 1 c shows a metal profile comprising an incipient cut.

Fig . 2a shows a channel arrangement comprising a first and a second metal profile arranged toward each other and joined together.

Fig. 2b shows a channel arrangement comprising a first and a second metal profile arranged toward each other and joined together.

Fig. 2c shows a channel arrangement comprising a first and a second metal profile arranged toward each other and joined together.

Fig. 3a shows the channel arrangement in fig. 2a having had material removed from the first metal profile.

Fig. 3b shows the channel arrangement in fig. 2b having had material removed from the first metal profile. Fig. 3c shows the channel arrangement in fig. 2c having had material removed from the first metal profile.

Fig. 4 shows rolling mil! for manufacturing a channel arrangement.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Fig. 1 a shows a metal profile 1 seen from a side view. The metal profile 1 comprises two elongated trench-like portions 3 and three flat portions 5.

Each of the trench-like portions 3 comprises a longitudinal axis L. The flat portions 5 are located next to each side of the trench- like portions 3. The flat portions 5 extend along the longitudinal axis L of the trench-like portions 3.

One of the fiat portions 5 is located between the two adjacent trench-like portions 3 and comprises a first incipient cut 10a and a second incipient cut 10b. The other two flat portions 5 are located on the opposite side of the respective trench-like portions 3.

The metal profile 1 has preferably been formed from a flat metal sheet. The thickness of the metal profile 1 is substantially uniform. Accordingly, the material thickness of the trench-like portions 3 and the flat portions 5 are essentially the same.

The metal profile 1 comprises four sides. The trench-like por- tions 3 extends from a first side S1 to a second side S2. The longitudinal axis of the trench-like portions 3 is perpendicular to the first side S1 and the second sid S2, and parallel with a third side S3 and a fourth side S4 of the metal profile 1. In an embodiment the trench-like portions 3 extend a longer distance in comparison to the length of first side S1 and the second side S2. Fig, 1 b shows a detail view of the first incipient cut 10a in the encircled area of fig. 1 a. The first incipient cut 10a intrudes a certain depth laterally into the metal profile 1 . The intruding depth is less than the thickness of the metal profile 1 .

The incipient cut 10a, 10b provides a weakening in the metal profile 1 that enables material between the first incipient cut 10a and the second incipient cut 10b to be removed. Upon removal of th material between the first incipient cut 10a and the second incipient cut 10b an edge is adapted to be formed, which edge extends aiong the length of the first incipient cut 10a and the second incipient cut 10b. Fig. 1 c shows a side view of a metal profile 1 having the same form as the metal profile 1 in fig. 1 a. The metal profile 1 comprises an incipient cut 10c located in the flat portion between the two trench-like portions 3. The incipient cut 10c extends in a loop, wherein materia! enclosed within the incipient cut 1 0c is adapted to be removed.

The incipient cut 10c provides a weakening in the metal profile 1 that enables material enclosed by the incipient cut 10c to be removed. Upon removal of the material enclosed by the incipient cut 10c an edge is adapted to be formed, which edge extends along the length of the incipient cut 10c.

According to an embodiment of the invention the metal profile 1 comprises one or more loop formed incipient cuts 10c at the flat portions 5 of the metal profile 1 , The one or more loop formed incipient cuts 10c enables one or more of the enclosed material to be removed.

The metal profile 1 in fig. 1 a-1 c are adapted to be arranged to- wards and joined to another metal profile 1 , and thereby forming a channel arrangement with channels defined between the two metai profiies 1 . The materiai at least partly enclosed between the incipient cuts 10a, 10b, 10c is adapied to be removed. The fiat portions 5 of the metai profile 1 and the other metal profile 1 are adapted to form flat regions. The channels of the channel arrangement are adapied to conduct a fluid. The fiat regions of the channel arrangement are adapted to conduct heat to or from the channels. it shall be understood that the metai profiles 1 in fig. 1 a-1 c are not restricted to two trench-iike portions 3 but the metal profiles 1 may comprise any number in plurality of trench-like portions 3 that are mutually separated by flat portions 5. Accordingly, it is possible to produce a channel arrangement comprising a large number of channels. Furthermore, it shall be understood that one or more of the flat portions 5 comprises the incipient cut 10a, 10b, 10c that enables removal of material.

Fig. 2a shows a channel arrangement 20 comprising a first metal profiie 1 a and a second metal profile 1 b arranged toward each other and joined together.

The first metal profile 1 a and the second metai profile l b have the form of the metal profile 1 disclosed in fig. 1 a and 1 b. Accordingly, the profiles 1 a, 1 b comprises the plurality of trench- like portions 3 and plurality of flat regions 21 .

The first metai profile 1 a comprises the first incipient cut 10a and the second incipient cut 10b located in the flat region 21 between the two trench-like ridges 3, The second metai profile 1 b Sacks incipient cut.

The first metal profile 1 a and the second metal profiie 1 b have been arranged so that the fiat portions 5 of the first metal profile 1a and the second metal profile 1 abut each other and so that the trench-iike portions 3 are directed in opposite directions, wherein the profiies 1 a, 1 b defines a first channel 22a and a second channel 22b between the profiles. The channels 22a, 22b are adapted to conduct a fluid.

The channel arrangement 20 comprises a piurality of joints 24 located in the fiat regions 21 between the first metal profile 1 a and the second metal profile 1 . The joints 24 are arranged adjacent to each side of the channels 22a _t 22b.

The joints 24 are adapted to hold the first metal profile 1 a and the second metal profile 1 b together. Furthermore, the joints 24 are adapted to have sufficient strength to maintain a certain pressure of the fiuid without leakage.

The joints 24 comprise a first joint 24a adjacent to the first channel 22a and a second joint 24b adjacent to the second channel 22b. The first incipient cut 10a and the second incipient cut 10b are arranged between the first joint 24a and the second joint 24b. The first incipient cut 10a and the second incipient cut 10b is adapted to enab!e removal of material 26 from the flat re- gion 21 between the first channel 22a and the second channel 22b.

Fig. 2b shows a channel arrangement 20 comprising a first metal profile l a and a second metal profile 1 b arranged toward each other and joined together. The first metal profile 1 a in fig. 2b is the first metal profile 1 a in fig. 1 c. The second metal profile 1 has the same form as the first metal profile 1 a but !acks the incipient cut. By means of the incipient cut 10c in the first metal profile 1 a, material enclosed by the loop formed incipient cut 10c is adapted to be removed from the channel arrangement 20.

Fig. 2c shows a channel arrangement 20 comprising a first metal profile 1 a and a second metal profile 1 b arranged toward each other and joined together. The first metal profile 1 a in fig. 2c is the first metal profile 1 a from fig. 1 a. Accordingly, the first metal profile 1 a comprises the plurality of trench-like portions 3 and plurality of flat regions 21. The second metal profile 1 b comprises a flat sheet of metal. Accordingly, the second metal profile 1 b lacks the trench-iike portions 3. The second metal profile 1 lacks the incipient cut.

The first metal profile 1 a and the second metal profile 1 b define channels 22a, 22b. The cross section of the channels in fig. 2c is half of the cross section of the channels 22a, 22b in fig. 2a.

It shall be understood that a single profile with trench-like portions 3 and flat portions 5 and another profile comprising at least fiat portions 5 arranged towards each other are sufficient in order to define the channels 22a, 22b of the channel arrangement 20. Furthermore, the incipient cut 10a, 10b, 10c for removal of material may be arranged in either the first metat profile 1 a or the second metai profile 1 b.

Fig. 3a shows the channel arrangement 28 in fig. 2a having had the material between the first incipient cut 10a and the second incipient cut 10b removed from the first metai profile 1 a. By means of the removal of the material 26, the thickness of the flat region 21 between the first channel 22a and the second channel 22b of the channel arrangement has been reduced by the thickness of the first metal profile 1 a, wherein the thickness of a part of the fiat region 21 has the thickness of the second metal profile 1 b.

As the material was removed from the flat region 21 , the first incipient cut 10a formed a first edge 30a and the second incipient cut 10b formed a second edge 30b. Each of the first edge 30a and the second edge 30b extends along the respective first incipient cut 10a and second incipient cut 10b. By means of the removal of material 26 from the flat region 21 the material consumption of the channel arrangement 28 is reduced. Moreover, the weight of the channel arrangement 28 is reduced.

Fig. 3b shows the channel arrangement in fig. 2b having had material 26 removed from the first metai profile 1 a. The material 26 removed was enclosed by the loop formed incipient cut 10c, wherein a corresponding loop formed edge 30 was formed.

Fig. 3c shows the channel arrangement in fig. 2c having had material 26 removed from the first metal profile 1 a. The materia! 26 that was located between the first incipient cut 10a and the second incipient cut 10b has been removed from the first metal profile 1 a.

The channel arrangement 28 in fig. 3a-3c is adapted to be used in a heat exchanger, preferably a solar absorber. By means of reducing the material consumption the cost of the heat exchanger is reduced.

It shall be understood that the channel arrangement 20 in fig. 2a-2c and the channel arrangements 28 in fig. 3a-3c are not re- stricted to two channels but the channel arrangement may comprise any number in plurality of channels that are separated by flat regions 2 . Accordingly, it is possible to produce channel arrangements 20, 28 comprising a large number of channels 22a, 22b.

Fig. 4 shows a roiling mill 35 adapted to be used in the method for producing a channel arrangement 28 from a first metai profile 1 a and a second metal profile 1 b. In a first step, the process comprises forming the first metal profile 1 a and the second metal profile 1 b. A first metai sheet 40a and a second metal sheet 40b are provided from first pair of collecting rolls 42 to a respective first pair of rolls 44, which rolls 44 are adapted to form the first metal sheet 40a and the second metal sheet 40b into the first metai profile 1 a and the second metal profile 1 b. The first pair of rolls 44 comprises protrusions and recessions that are adapted to form the trench-like portions 3 and the flat portions 5 of the first metal profile l a and the second metal profile 1 b. In a second step, the process comprises forming incipient cut 10a, 10b, 10c in at least one of the first metal profile 1 a and the second metal profile 1 b. The first metal profile 1 a and the second metal profile 1 b is provided to a respective second pair of ro!ls 46, which rolls 46 are adapted to form the incipient cut 10a, 10b, 10c. The second pair of rolls 46 comprises cutting means adapted to cut into a part of the thickness of the at least one of the first metal profile 1 a and the second metal profile 1 b. in a third step, the process comprises a) arranging the first metai profile 1 a towards a second metal profile 1 b so that trench-like portions 3 of the first metal profile 1 a are directed away from trench-like portions 3 of the second metai profile 1 b and fiat portions 5 of the first metal profile 1 a are abutting flat portions 5 of the second metal profile 1 b.

In a forth step, the process comprises b) joining the metai profiles 1 a, 1 b so that channels 22a, 22b between the profiles 1 a, 1 b are formed, which channels extends according to the trenchlike portions 3 of at least one of the first metal profile 1a and the second metal profile 1 b. The joining of the metal profiles 1 a, 1 b comprises providing the first metal profile 1 a and the second metal profile 1 b to a third pair of rol ls 48 that form a piurality of joints 24 at flat regions 21 on each side of the channels 22a, 22b. In a fifth step, the process comprises c) gripping a part of the material 26 to be removed and pulling a part of the material 26 in a direction along which the incipient cut 10a, 10b, 10c extends, wherein the material 26 is removed from the flat region 21 so that the thickness of the fiat region 21 becomes less than the sum of the thickness of the first metai profile 1 a and the second metal profile 1 b. The material 26 to be removed is gripped and provided to a second collecting roll 50. In a sixth step, the process comprises collecting the produced channel arrangement 28 on a second collecting roll 52.

The disclosed process in fig. 4 enables the channel arrangement 28 to be produced in a continuous manner. Accordingly, the channel arrangement 28 can be produced in a cost effective manner with reduced material consumption.

The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims.

For example, the channels 22a, 22b may have any type of form, such as circular cross section, rectangular cross section, etcetera. One and the same channel arrangement may also have channels with different shapes and/or cross section area. The joints 24, 24a, 24b may be arranged by various methods, such as welding, bracing, rolling, etcetera.

The incipient cut 10a, 10b, 10c may have various configurations, such as continuously or intermittent extending along the material 26 that is adapted to be removed from the at least one flat region 21 . The incipient cut 10a, 10b, 10c may partly or completely enclosing one or more material 26 that is adapted to be removed from the at least one flat region 21.