EP2322297B1 - Flat tube with turbulence filter for a heat exchanger, heat exchanger with such flat tubes and method and device for producing such a flat tube - Google Patents

Abstract

The tube (4) has crown walls (47, 48) and/or crowns of insert broad side walls (69) and the crown walls resting opposite to each other in a pipe height direction (70) and spaced at a distance from each other in the pipe height direction. One of the crown walls and/or the crowns rest at a pipe inner surface (12) of a pipe wall (10) of the tube. The crown walls are arranged in a pipe width direction (19). One crown wall and/or one crown are connected with another crown wall and another crown by a diagonal sidepiece wall (49).

Description

The present invention relates to a flat tube for heat exchangers, in particular for intercooler, with an inner turbulence insert and a heat exchanger, in particular a charge air cooler having such flat tubes and a method and an apparatus for producing such a flat tube.

Generic flat tubes usually serve for the fluidic connection of an inlet collecting container with an outlet collecting container of a heat exchanger, e.g. a charge air cooler or an oil cooler, for which the flat tubes stacked one above the other and are arranged with their tube broad sides adjacent to each other and open with their tube ends respectively in the inlet and the outlet header. In addition, preferably lamellar or wave-like plates are arranged between the flat tubes, which are soldered with their apexes on the broad sides of the flat tubes. The sheets are used to increase the heat exchange surface. Through the flat tubes flows a liquid or gaseous medium to be cooled, e.g. Charge air, and between the flat tubes and through the sheets flows through a gaseous or liquid, heat-absorbing medium, preferably air, wherein a heat exchange between the two media takes place.

For example, to improve heat transfer EP-A-160 5221 and DE 10 2006033570 A It is known that the flat tubes have internal turbulence plates or turbulence inserts. These serve primarily to generate a turbulent flow of the medium flowing through the flat tubes. In addition, the turbulence inserts with the Be soldered tube wall of the flat tubes, so that they also serve to increase the internal pressure resistance due to a Zugankerwirkung.

The turbulence inserts are, for example, corrugated sheets ("UVave fins"), which are produced for example by means of roll deformation and form a plurality of mutually adjacent, each extending in a tube longitudinal direction flow chambers. Alternatively, the turbulence inserts are so-called offset fins which respectively form flow chambers which are arranged one behind the other in the tube longitudinal direction, wherein the flow chambers arranged one behind the other are arranged offset in relation to one another in a tube transverse direction. This creates staggered edges that impinge upon the flow, creating turbulence. A possible embodiment of offset fins is for example from the DE 10 2006 031 675 A1 known.

To produce the flat tubes with internal turbulence insert, the prefabricated turbulence inserts are usually inserted into the prefabricated flat tubes and suitably soldered to them. This manufacturing process is relatively expensive. In particular, this is a multi-stage process in which the flat tubes must be taken several times in the hand, which brings high costs.

In addition, it is for example from the DE 10 2006 031 675 A1 known to manufacture the flat tubes together with the turbulence inserts from one piece. For this purpose, a portion of a flat strip is first deformed, among other things by means of roll deformation continuously to an endless turbulence insert, wherein laterally next to the deformed portion, the flat strip is left smooth. Subsequently, the smooth portions are folded and wound around the deformed portion, so that an endless flat tube is formed. The endless flat tube is then welded longitudinally and cut to length.

From the US 5,105,540 It is known to manufacture flat tubes with the turbulence inserts from two endless flat strips.

The object of the invention is to provide a method and a device, by means of the flat tube (s) for heat exchangers, in particular for intercoolers, with an internal turbulence insert, easy, fast and inexpensive to produce.

In addition, object of the present invention is to provide a flat tube for heat exchangers, in particular for intercooler, with an internal turbulence insert, which is simple, quick and inexpensive to produce, has a high stability to pressure load from the outside and inside and has good heat exchanger properties.

Another object of the invention is to provide a heat exchanger, in particular a charge air cooler, with such flat tubes.

These objects are achieved by a method having the features of claim 13, a device having the features of claim 27, a flat tube having the features of claim and a heat exchanger having the features of claim 12.

Figur 1:

Eine schematische, rohrschmalseitige Ansicht des erfindungsge- mäßen Wärmetauschers

Figur 2:

Einen schematischen Querschnitt des erfindungsgemäßen Flach- rohres

Figur 3:

Schematisch eine Seitenansicht einer erfindungsgemäßen Vorrich- tung

Figur 4:

Schematisch einen Querschnitt eines nicht abgekanteten Endlos- profilbleches

Figur 5:

Schematisch einen Querschnitt des abgekanteten Endlosprofilble- ches und eines abgekanteten Endlosflachbandmaterials zur Her- stellung einer Rohrwand

Figur 6:

Schematisch einzelne Schritte des Umformvorgangs des Endlos- flachbandmaterials und des Endlosprofilbleches zu einem Endlos- flachrohr mit Endlosturbulenzeinlage

Figur 7:

Schematisch zwei übereinander angeordnete Biegerollen

Figur 8:

Schematisch zwei übereinander angeordnete Abkantrollen einer ersten Abkanteinrichtung

In the following, we will explain the invention with reference to a drawing by way of example closer. Show it:

FIG. 1:

A schematic, narrow-side view of the tube according to the invention heat exchanger

FIG. 2:

A schematic cross section of the flat tube according to the invention

FIG. 3:

Schematically a side view of a Vorrich- device according to the invention

FIG. 4:

Schematically a cross section of a non-folded endless profile sheet

FIG. 5:

Schematically a cross section of the bent Endlosprofilble- ches and a folded endless flat strip material for the production of a pipe wall

FIG. 6:

Schematic individual steps of the forming process of the endless flat strip material and the endless profile sheet to an endless flat tube with Endsturbulenzeinlage

FIG. 7:

Schematically two benders arranged one above the other

FIG. 8:

Schematically two stacked Abkantrollen a first Abkanteinrichtung

The heat exchanger 1 according to the invention Fig.1 ) has a Einiasssammelbehälter 2, spaced apart arranged Auslasssammebehälter 3, a plurality of parallel and juxtaposed, spaced from each other flat tubes according to the invention 4, and preferably between the flat tubes 4 arranged and related to these lamellar or wave-like sheets 5, the To increase the heat exchange surface serve. The flat tubes 4 are arranged between the two reservoirs 2, 3 and connect these fluidically with each other. The inlet header 2 has an inlet opening for introducing the first medium to be cooled, in particular charge air, into the inlet header tank 2. The outlet header 3 has an outlet opening for discharging the cooled first medium from the outlet header 3. In this case, an inlet connection piece 6 for connection to the cooling or heating system and, preferably, an outlet connection piece 7 for connection to the cooling or heating system adjoin the inlet opening. The heat exchanger 1 according to the invention is therefore a countercurrent heat exchanger in which a first, liquid or gaseous medium to be cooled or heat flows from the inlet collecting container 2 in a flow direction 8 through the flat tubes 4 into the outlet collecting container 3 and thereby cooled becomes. The cooling takes place by heat exchange with a second, cooling or heat-receiving, preferably gaseous, medium, for example air, which is in a countercurrent direction 9 between the Flat tubes 4, around the lamellar sheets 5 perpendicular to the flow direction 8 flows around and thereby absorbs heat.

An inventive flat tube 4 ( Fig. 2 ) has in each case a tube wall 10 with a tube wall outer surface 11 and a tube wall inner surface 12, and two mutually parallel and mutually parallel Rohrbreitseitenwandungen 13 and two mutually parallel and mutually parallel Rohrschmalseitenwandungen 14 through which the Rohrbreitseitenwandungen 13 merge into each other. Both the tube wide side walls 13 and the two tube narrow side walls 14 are preferably planar or flat or plate-shaped, so that the flat tube 4 has a rectangular cross-section. However, the tube narrow side walls 14 can also be rounded or half round, so that the flat tube 4 has a substantially flat oval cross section (not shown). The tube wall 10 also defines a tube interior, which forms a parallel to a central tube longitudinal axis 15 extending flow channel 16 of the flat tube 4. In addition, the flat tube 4 according to the invention has a tube center plane 17 which contains the tube longitudinal axis 15 and is arranged centrally between the two tube broad side walls 13 and parallel thereto. The flat tube 4 is preferably formed symmetrically to the tube center plane 17. In addition, the flat tube 4 has a tube longitudinal direction parallel to the tube longitudinal axis 15 18 and a tube width direction 19, which is perpendicular to the tube longitudinal direction 18 and parallel to the tube center plane 17 on.

In addition, the tube wall 10 is produced by roll deformation and is longitudinally closed, in particular by means of a parallel to the tube longitudinal direction 18 extending longitudinal weld 20, which will be discussed in more detail below. The longitudinal weld seam 20 is expediently arranged on one of the two narrow side walls 14 and centrally in relation to the latter and extends parallel to the tube longitudinal axis 15. By means of the longitudinal weld seam 20, abutting or abutting one another are present Pipe wall longitudinal edges or pipe wall butt edges 75 ( Fig. 6 ) of the tube wall 10 welded together. The adjoining longitudinal tube wall edges 75 may, however, also be connected to one another in another way, for example glued or soldered together.

The flat tube 4 according to the invention also has an inner, arranged in the flow channel 16 stabilization insert or turbulence insert 21, whose configuration will be discussed in more detail below. The turbulence insert 21 is usually also referred to as turbulator or Fin.

The production method according to the invention by means of the device 22 according to the invention is described in more detail below:

The device 22 according to the invention ( Figure 3 ) comprises a turbulence inlay prefabrication device 23, a tube wall material prefabrication device 24, an assembly device 25, a plurality of bending devices 26a, b, preferably a welding device 27 and a separating device 29.

The turbulence inlay prefabrication device 23 has a first storage device 30 for a first metallic endless flat strip material 31 for producing the turbulence insert 21, preferably one of the first storage device 30 in a horizontal conveying direction 32 downstream punching device 28, a deformation device 33 downstream of the punching device 28 in the conveying direction 32 and one of Deformation device 33 downstream first Abkanteinrichtung 50.

The storage device 30 is, for example, a tape storage and has at least one supply roll 74, from which the advantageously one or both sides solder-plated, metallic first endless flat strip material 31 is substantially continuously unwound. The first endless flat strip material 31 expediently has a wall thickness of 0.05 to 0.5 mm, preferably 0.1 to 0.2 mm. In addition, the first endless flat strip material 31 is preferably made of aluminum and / or copper and / or steel. The leadership of the first endless flat strip material 31 is advantageously carried out so that the planar flat endless belt material 31 is aligned horizontally. In addition, the storage device 30 preferably in a conventional manner in the conveying direction 32 of the supply roll 74 downstream of a plurality of dancing rollers (not shown), which are arranged one behind the other and vertically offset from each other in the conveying direction 32 and are independently movable in the vertical direction, so that they can clamp a variable length of the first ribbon material 31. Of the dancing rollers, the first flat strip material 31 is then conveyed on to the punching device 28.

The punching device 28 is used for punching out holes (not shown) from the first endless flat strip material 31. By means of the punching device 28, one or more rows of holes extending parallel to the conveying direction 32 are produced. The holes are used for turbulence generation, which will be discussed in more detail below. For this purpose, the punching device 28 has at least two opposing punching rollers, between which the first flat strip material 31 is performed. In this case, one of the two punch rollers corresponding, protruding punch elements and the other punching roller has corresponding recesses into which the stamp elements can dip.

As an alternative to the punching device or in addition thereto, an embossing device (not shown) for introducing turbulence-generating embossments into the first flat strip material 31 is present. The embossing device has, in a manner known per se, two opposing embossing rollers.

From the punching device 28 and the embossing device, the first ribbon material 31 is then further promoted to the deformation device 33.

The deformation device 33 serves to deform or transform the first flat strip material 31 into a profiled endless profile sheet 35 having a predetermined cross-sectional profile (FIG. FIG. 4 ). The deformation is expediently carried out by means of roll deformation, also referred to below as embossing. For this purpose, the deformation device 33 has two vertically superimposed, rotatably mounted deformation rollers or embossing rollers 34a, 34b, whose axes of rotation aligned horizontally and perpendicular to the conveying direction 32 and which are arranged vertically aligned with each other. The two embossing rollers 34a, 34b are also drivable in opposite directions of rotation and spaced from each other so that the first flat strip material 31, when it is performed between the two embossing rollers 34a, 34b, is embossed. For introducing the embossments into the first flat strip material 31, the two embossing rollers 34a, 34b each have outer, circumferential and substantially cylindrical embossing surfaces, which each have the positive or negative embossing shapes of the embossings to be introduced into the first flat strip material 31. In particular, the embossing surface of the lower embossing roller 34b has positive, convex or protruding embossing shapes, and the embossing surface of the upper embossing roller 34a has the corresponding negative, concave, ie inwardly curved embossing shapes.

The endless profile sheet 35 produced has a profiled sheet metal wall 43, two lateral profiled sheet longitudinal edges 36, a first profiled sheet broad side 44 and a second profiled sheet broadside 45 opposite the first profiled sheet broad side 44, a longitudinal extent in the conveying direction 32 and a transverse extent in a horizontal profiled sheet transverse direction 37 perpendicular to the conveying direction 32. Conveniently, the first profile sheet broadside 44 is disposed above the second profile sheet broadside 45.

Seen from one of the two profiled sheet longitudinal edges 36 and in profiled sheet transverse direction 37, the endless profiled sheet 35 initially has a first outer undeformed, embossing-free, planar, plate-shaped section 38. The first outer planar section 38 is expediently oriented horizontally. As seen in profile sheet transverse direction 37, a first deformed or profiled, in particular embossed, section 39 adjoins the first outer planar section 38. At the first deformed Section 39 closes in profiled sheet transverse direction 37 seen a central undeformed, embossing-free, planar, plate-shaped portion 40 at. The first profiled sheet broad side 44 and the second profiled sheet broad side 45 of the central planar section 40 are respectively coplanar with the first profiled sheet broad side 44 and the second profiled sheet broad side 45 of the first outer undeformed section 38. A second deformed or closed section, as seen in sectional sheet transverse direction 37, adjoins the central flat section 40 ., profiled, in particular embossed, section 41. A second outer undeformed, embossing-free, planar, plate-shaped section 42 adjoins the second deformed section 41 when viewed in profile sheet transverse direction 37. The first profiled sheet broad side 44 and the second profiled sheet broad side 45 of the second outer planar section 42 are respectively coplanar with the first profiled sheet broad side 44 and second profiled sheet broad side 45 of the first outer undeformed section 38.

The two deformed sections 39, 41 each have a trapezoidal profile 46, as seen in cross-section. That is, the two deformed portions 39, 41 are formed in the manner of a trapezoidal sheet or a trapezoidal sheet. The trapezoidal profile 46 and thus the deformed portions 39, 41 each have first and second, preferably horizontally extending, planar, plate-shaped parallel vertex walls 47, 48, the first vertex walls 47, seen in the vertical direction and in sectional sheet transverse direction 37, facing the second vertex walls 38 offset or spaced are arranged. The first apex walls 47 are expediently arranged higher than the second apex walls 48. In addition, the first profiled sheet broad side 44 and the second profiled sheet broad side 45 of the second crest walls 48 are each coplanar with the first profiled sheet broad side 44 and the second profiled sheet broad side 45 of the planar sections 38, 40, 42. In addition, the first and second apex walls 47, 48 are arranged alternately in the transverse direction 37 of the profile. By oblique, preferably planar, plate-shaped Schenkeiwandungen 49 is in each case a first apex wall 47 with a second apex wall 48 connected. In particular, a leg wall 49 with a first apex wall 47 encloses an angle α, where 90 <α ≦ 135 °. The leg walls 49 and the apex walls 47, 48 and thus the trapezoidal profile 46 have a longitudinal extent in the conveying direction 32.

Preferably, the endless profile sheet 35 is formed symmetrically to a central, parallel to the conveying direction 32 and perpendicular to the profile sheet transverse direction 37 extending profile sheet metal center plane 65. The profile sheet center plane 65 intersects the endless profile sheet 35 in the central planar area 40. Starting from the profile sheet center plane 65, on either side one of the two deformed areas 39, 41 joins the central planar area 40. In turn, one of the two planar areas 38, 42 adjoins each of the two deformed areas 39, 41.

Furthermore, the extension of the first apex walls 47 in profile sheet transverse direction 37 is expediently smaller than the extension of the second apex walls 48. The first apex walls 47 preferably have an extension in profile sheet transverse direction 37 of 1 to 5 mm. The second crest walls 48 preferably have an extension in profile sheet transverse direction 37 of 1 to 5 mm.

In addition, the stamped holes or the turbulence-generating embossings are expediently introduced so that they are present in the leg walls 49 after deformation.

As an alternative to the trapezoidal profile 46, the two deformed sections 39, 41 each have, viewed in cross-section, a different wave profile, in particular a sinusoidal wave profile or a triangular profile or a rectangular profile.

The first Abkanteinrichtung 50 serves to bend or bending the Endlosprofilbleches 35 in the region of the two profiled sheet longitudinal edges 36, ie in the region of the two outer planar portions 38, 42. In particular, the continuous profile sheet 35 is angled or bent by 90 °. Thereby two lateral web walls 51 are formed, which are angled at 90 ° with respect to the profile sheet transverse direction 37 and are thus aligned vertically. The two web walls 51 each have one of the two Profübiechlängskanten 36 at the end. The folding is preferably done by roll deformation. As a result, the first Abkanteinrichtung 50 two stacked Abkantrollen 82 a, 82 b on ( Fig. 8 ).

The upper Abkantrolle 82 a has a central, cylindrical lateral surface 83, with the upper Aban roll 82 a presses on the central planar portion 40. At the middle Maritelfläche 83 close on both sides, in turn, two cylindrical lateral surfaces 84, which have a smaller diameter than the central lateral surface 83 and which rest against the first apex walls 47. An outer folding disk 85, each having a cylindrical lateral surface 85a, adjoins the two cylindrical lateral surfaces 84. The diameter of the lateral surfaces 85a corresponds to the diameter of the central lateral surface 83. The two lateral surfaces 85a press on the second outer planar portions 38,42 on it, however, a portion of the second outer planar portions 38,42 each protrudes beyond the outer lateral surfaces 85a.

The lower Abkantrolle 82b has a cylindrical outer surface 86, to each end of which an outer Abkantscheibe 87 connects with a cylindrical lateral surface 87a. The two lateral surfaces 87a have a larger diameter than the central lateral surface 86. The central jacket surface 86 abuts the second apex walls 48 and a portion of the outer planar portions 38, 42. The over the outer lateral surfaces 85a of the upper Abkantrolle 82a protruding part of the outer planar portions 38,42, is bent between the two Abkantscheiben 85, 87.

The tube wall material prefabrication device 24 is arranged parallel to the turbulence pre-fabrication device 23, in particular below it. The pipe wall material prefabrication device 24 has a second storage device 52 for a second metallic endless flat strip material 53 for producing the tube wall 10 of the flat tubes 4, and preferably one of the second storage device 52 in the conveying direction 32 downstream second Abkanteinrichtung 54 on.

The second storage device 52 is also, for example, a tape storage and has at least one supply roll 55, from which the suitably one or both sides solder-plated, metallic second endless flat strip material 53 is substantially continuously unwound. The second continuous-filament strip material 53 expediently has a wall thickness corresponding to the desired wall thickness of the tube wall 10 of the flat tube 4 to be produced of 0.2 to 0.8 mm, preferably 0.25 to 0.35 mm. In addition, the second endless flat belt material 53 preferably consists of aluminum and / or copper and / or steel, wherein it does not have to consist of the same material as the first endless flat belt material 31. In addition, the second endless flat strip material 53 has two longitudinal band edges 56 extending parallel to the conveying direction 32, and one, preferably horizontal, first, flat band width side 60 and one, preferably horizontal, second planar band width side 61. The first bandwidth page 60 is preferably arranged above the second bandwidth page 61. The guide of the second endless flat strip material 53 is thus also expediently likewise such that the plate-shaped endless flat strip material 53 is aligned horizontally. In particular, the first and second endless belt webbing 31, 53 are both horizontally aligned and aligned in the vertical direction. The second storage device 52 preferably also has a plurality of dancing rollers (not shown) arranged downstream of each other in the conveying direction 32 of the supply roll 55, which are each arranged offset one behind the other in the conveying direction 32 and are movable independently of one another in the vertical direction that they can clamp a variable length of the second ribbon material 53. From the dancing rollers, the second flat strip material 53 is then conveyed on to the second bending device 54.

The second Abkanteinrichtung 54 is used for folding or bending or bending of the second endless flat strip material 53 in the region of the two band longitudinal edges 56. In particular, the second endless flat strip material 53 is angled by 90 °. That is, there are two lateral web walls 57 ( FIG. 5 ) are formed, which are angled upward by 90 ° with respect to a horizontal transverse tape direction 58 and are thus vertically aligned. The two web walls 57 each have one of the two band longitudinal edges 56 at the ends. For folding, the second Abkanteinrichtung 54 analogous to the first Abkanteinrichtung 50 has an upper and lower Abkantrolle. The lower Abkantrolle is analogous to the lower Abkantrolle 82 a of the first Abkanteinrichtung 50 constructed. The upper Abkantrolle expediently has a continuous cylindrical surface.

The merging device 25 serves to bring together the folded-over continuous profile sheet 35 and the folded-over second endless flat strip material 53 such that one of the two profile sheet broad sides 44, 45 rests against one of the two broadband sides 60, 61. The endless profile sheet 35 and the second endless flat strip material 53 are thus placed on each other on the wide side. For this purpose, the merging device 25 is disposed downstream of the two Abkanteinrichtungen 50,54 in the conveying direction 32. The merging device 25 has a plurality of deflection and guide rollers 59 for deflecting and for bringing together the endless profile sheet 35 and the second endless flat strip material 53. In particular, the endless profile sheet 35 and the second endless flat belt material 53 are brought together so that the endless profile sheet 35 is inserted into the second endless flat belt material 53 and placed thereon. That is, so that the second profile sheet broadside 45 rests on the first broadband side 60 and the two web walls 51 of the endless profile sheet 35 rest against the inside of the two web walls 57 of the second flat strip material 53. The endless profile sheet 35 is thus received after the merge laterally form-fitting in the second flat strip material 53. In particular, it is in profile sheet or strip transverse direction immovable 37,58 arranged and guided in the second flat strip material 53.

Downstream of the joining device 25 in the conveying direction 32 are the bending devices 26a, b for forming an endless flat tube 62 (FIG. Fig. 6 ). The second endless flat strip material 53 is bent around the axes parallel to the conveying direction 32 by means of the bending devices 26a, b so that the longitudinally slotted tube wall 10 of the flat tube 4 to be produced is formed. In particular, the tube wall 10 consequently has the two tube broad side walls 13 and the two narrow tube side walls 14 and expediently a rectangular cross section. For this purpose, the endless flat strip material 53 is bent around bending axes parallel to the conveying direction 32 such that the two longitudinal band edges abut one another and form two mutually opposite longitudinal tube wall edges 75. In addition, the second endless flat strip material 53 is bent so that the two web walls 57 are arranged opposite one another and form one of the two narrow pipe side walls 14. For this purpose, the second endless flat strip material 53 on both sides of a central, perpendicular to the strip transverse direction 58 strip center plane 76 in each case by 90 °, in particular upwards, angled. The bending regions or bending edges or bending edges are equally spaced from the strip center plane 76. The Rohrbreitseitenwandungen 13 of the tube wall 10 of the endless flat tube 66 are expediently aligned vertically and the two pipe narrow side walls 14 are suitably aligned horizontally.

The continuous profiled sheet 35 is bent simultaneously with the second endless flat strip material 53 by means of the bending devices 26a, b in such a way around the conveying direction 32 axes that it forms a flat tubular, longitudinally slotted Endrolsturbulezeinlage 66 whose cross-sectional profile corresponds to the cross-sectional profile of the turbulence insert 21 of the flat tube 4 to be produced. That is, the endless profile sheet 35 is bent to the tubular Endurbsturbulezeinlage 66, wherein the Endrosturbulenzeinlage 66 of the from the second endless flat strip material 53 formed tube wall 10 is enclosed or wrapped. The endless profiled sheet 35 is bent so that the two profiled sheet longitudinal edges 36 abut one another and form longitudinal insert edges 77 (FIG. Fig. 6 ). In addition, the endless profile sheet 35 is bent so that the two web walls 51 are arranged opposite one another and are expediently oriented horizontally. For this purpose, the endless profile sheet 35 on both sides of the profile sheet center plane 65 in the central planar section 40 in each case by 90 °, in particular upwards, angled. The buckling areas or bending edges or bending edges are equally spaced from the profile sheet metal center plane 65. Thereby, the two deformed portions 39,41 are folded on each other, so that the first apex walls 47 of the first deformed portion 39 and the first apex walls 47 of the second deformed portion 41 facing each other in pairs, in particular in pairs and the second crest walls 48 of the first deformed portion 39 and the second crests 48 of the second deformed portion 41 are also opposed in pairs, but spaced from each other.

The Endlosturbulenzeinlage 66 formed by bending the Endlosprofilbleches 35 and consequently also the turbulence insert 21 of the flat tube 4 to be produced each have a circumferential, longitudinally slotted Einlagenwandung 67. The Einlagenwandung 67 has two opposing, preferably planar, Einlagenschmalseitenwandungen 68 and two opposing profiled Einlagenbreitseitenwandungen 69 on. The Einlagenbreitseitenwandungen 69 have an extension direction parallel to the Rohrbreitseitenwandungen 13 and parallel to the tube width direction 19. One of the two narrow side walls 68 is formed by the two opposing web walls 51, the other is formed by the non-angled portion of the central planar portion 40. The Einlagenschmalseitenwandungen 68 lie on the inside of the pipe narrow side walls 14, so are parallel to these. The Einlagenbreitseitenwandungen 69 are mainly formed by the two deformed portions 39,41. As a result, the two Einlagenbreitseitenwandungen 69 each mutually parallel first and second apex walls 47,48, and the leg walls 49 and thus also each a trapezoidal profile. The first apex walls 47 of a Einlagenbreitseitenwandung 69 are seen in the tube height direction 70 and in the tube width direction 19 seen offset from the second apex walls 48 or spaced. In addition, the first and second apex walls 47, 48 of an insert wide side wall 69, viewed in the tube width direction 19, are arranged alternately. In addition, the first and second vertex walls 47, 48 of an insert broad side wall 69 extend in the tube width direction 19 and in the tube longitudinal direction 18 or are parallel to the tube center plane 17.

In addition, the first apex walls 47 of one Einlagenbreitseitenwandung 69 and the first Scheitelwandungeri 47 of the other Einlagenbreitseitenwandung 69 in a direction of the pipe width direction 19 and the pipe longitudinal axis 15 vertical pipe height direction 70 seen in pairs opposite. In particular, the first apex walls 47 lie flat against one another in pairs. The first Schweitelwandungen 47 thus preferably meet in the tube center plane 17. Here are the first apex walls 47 Einlagenbreitseitenwandung 69 to the first apex walls 47 of the other Einlagenbreitseitenwandung 69 preferably parallel. The second apex walls 48 of one Einlagenbreitseitenwandung 69 and the second crest walls 48 of the other Einlagenbreitseitenwandung 69 are in pipe height direction 70 seen in pairs opposite, but they are spaced apart in the tube height direction 70, so do not protrude into the flow channel 16 to the tube center plane 17. In this case, the second crest walls 48 of a Einlagenbreitseitenwandung 69 to the second crest walls 48 of the other Einlagenbreitseitenwandung 69 are preferably parallel. In particular, the second apex walls 48 are in each case flat against the pipe wall inner surface 12 of the tube wall 10 of the endless flat tube 62 at. The second vertex walls 48 are thus supported on the pipe wall 10, in particular on the pipe wall inner surface 12. A Einlagenbreitseitenwandung 69 extends in the tube height direction 70 seen so preferably only on one side of the tube center plane 17 and from a Rohrbreitseitenwandung 13 to the tube center plane 17 out.

Due to the described arrangement of the apex and Schenkelwandungen 47,48,49, the Endlosturbulenzeinlage 66 has a honeycomb-shaped structure or a honeycomb profile. In particular, the endless turbulence insert 66 has a plurality of first flow chambers 71, which are arranged adjacent to each other in the tube transverse direction 70 and each have a hexagonal, in particular a regular or regular hexagonal cross section which is delimited by two opposite second apex walls 48 and the adjoining four leg walls 49. The first flow chambers 71 also have a longitudinal extent in the direction of the tube longitudinal direction 18. The extent of the first flow chambers 71 in the tube height direction 70 corresponds to the tube height, so that the honeycomb-shaped structure is formed in a single row.

In addition, in each case two second flow chambers 72 are formed between each two first flow chambers 71, which are each delimited by a first apex wall 47, the tube wall 10 and the two adjoining the first apex wall 47 two leg walls 49. The second flow chambers 72 each have a trapezoidal cross-section and also a longitudinal extent in the direction of the tube longitudinal direction 18. In each case two arranged between each two first flow chambers 71 second flow chambers 72 are arranged seen in the tube height direction 70 in pairs one above the other.

In addition, there are two third flow chambers 73 arranged on the narrow side of the tube or on the edge or end, each of which has one of the two narrow side walls 68, two half second walls 48 and two leg walls 49 are limited. The third flow chambers 73 thus have a cross section of a bisected hexagon.

As already explained above, the bending devices 26a, b serve for bending, in particular by means of roll deformation of the second endless flat strip material 53 together with the endless profile sheet 35 to the long-side slit endless flat tube 62 (described above). Fig. 6 ). In this case, two different types of forming or bending devices 26a, b are expediently present. The first bending devices 26a of the device 22 according to the invention each have a lower and an upper forming or bending roller 63a, 63b (FIG. Fig. 7 ), which are respectively arranged above and below the second flat strip material 53 and the endless profile sheet 35 inserted therein, wherein axes of rotation of the bending rolls 63a, 63b are aligned parallel to the axes of rotation of the embossing rolls 34a, 34b and to each other in a vertical direction. The two bending rollers 63a, 63b are drivable with respect to each other in opposite directions of rotation, wherein the upper bending rollers 63a the same direction of rotation as the upper embossing roller 34a and the lower bending rollers 63b have the same direction of rotation as the lower embossing roller 34b.

The upper bending rollers 63a preferably have a central, cylindrical lateral surface 78 and two adjacent conical lateral surfaces 79 tapering away from the central lateral surface 78. The extension of the central lateral surface 78 in the direction of the axis of rotation of the respective bending roller 63a corresponds to the extension of a pipe narrow side wall 14 of the endless flat tube 62 to be produced in the tube height direction 70. The lower bending rollers 63b each have a central, cylindrical lateral surface 80 and two adjacent conical, extending from the Central jacket surface 80 away widening lateral surfaces 81. Thus, the upper and lower bending rollers 63a, 63b have a positive / negative shape with respect to each other.

For bending, in each case the central lateral surface 80 of a lower bending roller 63b abuts against the second broadband side 61 or presses on it. moreover The two conical lateral surfaces 81 also abut on the second bandwidth side 61. The central lateral surface 78 of an upper bending roller 63 a is supported on the central, planar section 40 and presses on it. The two conical lateral surfaces 79 abut against the second apex walls 48. As a result, the second flat belt material 53 performed between the two bending rollers 63a, 63b and the endless profile sheet 35 are successively bent or bent around the upper bending roller 63a during rolling due to the negative / positive shape of the bending rollers 63a, 63b. That is, the deformed portions 39, 41 are bent toward each other and onto the upper bending rollers 63 a ( Fig. 6 ). In this case, the degree of expansion of the lower conical lateral surfaces 81 to each subsequent bending device 26 toward something and the degree of taper of the upper conical lateral surfaces 79 also increases.

By means of the first bending means 26a, the second flat strip material 53 and the endless profile sheet 35 are bent as long as an upper bending roll 63a still has space between the deformed sections 39,41, ie the pipe wall 10 is not yet completely closed.

Subsequently, the second ribbon material 53 and the endless profile sheet 35 are further bent and deformed by the second bending means 26b until they have the desired cross-sectional shape. The second bending devices 26b are thus arranged downstream of the first bending devices 26a in the conveying direction 32. The second bending devices 26b each only have only lower bending rollers 63b, in which the conicity of the conical lateral surfaces 81 increases successively until the lateral lateral surfaces 81 are perpendicular to the central lateral surface 80.

In the welding device 27 adjoining the last bending device 26b in the conveying direction 32, the opposing longitudinal tube wall edges 75 are continuously welded together in a manner known per se, so that a closed, prefabricated endless flat tube 62 is produced. During welding, the two pipe wall longitudinal edges 75 For example, by means of pressure rollers which act on the two pipe broad side walls 13, pressed against each other and the material heated in the region of the tube wall longitudinal edges 75 so that it welded together to form the longitudinal weld 20. Expediently, the welding takes place by means of induction welding.

Preferably, however, not only the two longitudinal tube wall edges 75, but also simultaneously the two longitudinal insert edges 77 are welded together in the welding device 27. That is, by squeezing the two longitudinal tube wall edges 75 and the two Einlaglängskanten 77 are pressed against each other and the material heated in the region of the longitudinal insert edges 77 so that it is welded together. Conveniently, only one weld, namely the longitudinal weld 20 is formed, so that in addition the tube wall 10 and the Endlosturbulenzeinlage 66 are welded together via the longitudinal weld 20, so that the tube wall 10 and the Endlosturbulenzeinlage 66 are firmly connected.

In addition, the insert longitudinal edges 77 can only be soldered together due to the heat during welding of the tube wall longitudinal edges 75. For this purpose, flux is expediently present, which, preferably on the inside, is present on the insert longitudinal edges 77.

As an alternative to welding or soldering of the longitudinal insert edges 77 or additionally soldered due to the heat during welding, the slotted Einlagenschmalseitenwandung 68 with the pipe wall inner surface 12, so that the tube wall 10 and the Endlosturbulenzeinlage 66 are firmly connected to each other.

In addition, the flat tube 4 in the region of the two longitudinal tube wall edges 75 can also be connected by means of a fold connection known per se or otherwise longitudinally.

Of course, instead of the welding device 27, any other type of connecting device, e.g. a soldering device or an adhesive device may be provided.

The separating device 29 of the device 22 according to the invention expediently has a knife (not shown) for cutting the endless flat tube 62 along a preferably vertical dividing line so that the endless flat tube 62 is separated into individual flat tubes 4 of the desired tube length. The knife is pivoted or rotated, for example, about a horizontal, parallel to the conveying direction 32 axis for separation. In addition, in order to compensate for the advancing movement of the endless flat tube 62, the knife can likewise be moved in the conveying direction 32 during the cutting process in a manner known per se ("flying knife"). According to a preferred embodiment of the invention, however, the knife is immovable in the conveying direction 32 ("standing knife"), wherein the movement of the endless flat tube 62 by a correspondingly chamfered in the conveying direction 32, the movement of the endless flat tube 62 balancing shape of the knife or by a corresponding inclination of the Messers is compensated.

The cut flat tubes 4 are then preferably soldered in a soldering oven. Because of the preferably double-sided solder plating of the first and second endless flat strip material 31, 53, the first top walls 47 lying in pairs are soldered together and the second top walls 48 are soldered to the pipe wall inner surface 12. This results in a solid composite of turbulence insert 21 and tube wall 10th

On the one hand, it is advantageous in the production method according to the invention by means of the device 22 according to the invention that the flat tube 4 according to the invention, including the turbulence insert 21, is produced continuously or on-line. As a result, the flat tube 4 can be produced quickly and inexpensively.

When the endless turbulence insert 66 and the tube wall 10 are firmly joined together when welded together, the endless turbulence insert 66 within the tube wall 10 can no longer slip. As a result, the endless flat tube 62 can be easily separated in the separating device 29. In addition, the produced flat tubes 4 can be easily cut by hand at a later date by means of a saw, without that they were previously in the brazing furnace.

In addition, both the positive arrangement of the turbulence insert 21 within the tube wall 10 and the flat tube shape of the turbulence insert 21 have the advantage that the turbulence insert 21 supports the tube wall 10, so that the stability of the flat tube 4 according to the invention, in particular the compressive strength under pressure on the Rohrbreitseitenwandungen 13 is significantly increased. In addition, the bursting strength is improved, in particular when the turbulence insert 21 is longitudinally closed, in particular welded. If the turbulence insert 21 is soldered over a large area to the tube wall 10, the strength increases even further. Due to the profiled broadsides 44,45 and the formation of the flow chambers 71,71,73 also the heat exchange is improved.

In particular, the honeycomb structure of the turbulence insert 21 further improves the stability of the flat tube 4. Because the pairs abutting each other first vertex walls 47 are based flat against each other in the middle of the pipe. As a result, the Einlagenbreitseitenwandungen 69 are based on each other in the tube height direction 70 from. In addition, the second apex walls 48 are supported flat on the tube wall 10. Thus, high pressure forces can be absorbed at external pressure. The oblique leg walls 49 ensure optimum power transmission.

In particular, when the turbulence insert 21 is soldered to the tube wall 10 and the stacked first vertex walls 47 are also soldered together, the stability of the flat tube 4 increases further. For the leg walls 49 are firmly clamped at both ends. In addition, the leg walls 49 have seen a smaller extent perpendicular to the tube longitudinal direction 18 than conventional wave-Fins whose leg walls extend over the entire height of the tube, from a Rohrbreitseitenwandung to the other. Because the leg walls 49 preferably only extend over half of the pipe height. For this reason too, the leg walls 49 are less prone to buckling from the outside when pressure is applied.

Also, the turbulence inserts 21 act as tie rods, so that the flat tubes 4 withstand high internal pressures.

Since the stability is significantly improved, in particular due to the honeycomb-shaped structure, the wall thickness of the turbulence insert 21 can be very small. Preferably, it is 0.05 to 0.5 mm, preferably 0.1 to 0.2 mm. This saves material on the one hand. On the other hand, reduces the surface of the apex walls 47,48 and the leg walls 49, to which the heat exchanger medium flowing through the flat tube 4 impinges upon entry into the flat tube 4. Thus, the pressure losses are significantly reduced.

As already explained above, it is also within the scope of the invention to introduce into the endless profile sheet 35 other profiles, so that the two deformed portions 39, 41 alternative to the trapezoidal profile 46 another wave profile, for example, each seen in cross section a sinusoidal wave profile or a triangular profile or have a rectangular profile with each first and second crest walls or vertices. In this case, the endless profile sheet 35 is suitably bent in each case so that the first apex walls or vertices of the two opposite Einlagenbreitseitenwandungen 69 come to lie in pairs on each other to ensure the described supporting effect. The two Einlagenbreitseitenwandungen 69 are therefore based in the tube height direction 70 preferably at several points together. In addition, the second vertex walls or vertexes of the two opposite Einlagenbreitseitenwandungen 69 are preferably on the pipe wall 10, in particular the respective pipe broad side wall 13 and based on this. In addition, first flow chambers are formed in an analogous manner as in the trapezoidal profile, which are each bounded by the pairwise opposite second crest walls or crests of the two opposite Einlagenbreitseitenwandungen 69 and adjoining the two second crest walls or vertices four leg walls. The second flow chambers are also delimited in an analogous manner as in the case of the trapezoidal profile of the first apex walls or vertices, the two leg walls adjoining the first apex walls or vertexes and the tube wall 10.

Advantage of the trapezoidal profile 46, however, is the resulting honeycomb structure when bending and flipping the deformed portions 39, 41. For the trapezoidal profile 46 small deformation tolerances are harmless, since a small offset of the superimposed first apex walls 47 in the tube width direction 19 relative to each other harmless, because there is still enough contact surface available.

Also seen thermodynamically, the flat tubes 4 according to the invention, in particular due to the honeycomb shape of the turbulence insert 21 designed very low. For the first apex walls 47 are preferably in the region of the tube center each other. Thus, areas with double wall thickness are formed there. However, the region of the center of the pipe is the region in which the temperature of the flow medium flowing through the flat tube 4 is highest, that is to say that most of the heat has to be dissipated. Since the heat conduction in the flat tube 4 largely takes place via the insert wall 67 of the turbulence insert, the heat dissipation is optimized by the double wall thickness in the region of the tube center.

Furthermore, it is advantageous that even very long tubes can be produced with the method according to the invention, which are later cut into individual, shorter flat tubes with the desired length. This is not possible in the multi-stage process according to the prior art since the insertion of the turbulence inserts from a certain pipe length is no longer possible.

It is also within the scope of the invention to pull off the first endless flat strip material 31 and the second endless flat strip material 53 from a common storage device, in particular from a common supply roll. Subsequently, the two endless flat belt materials 31,53 diverge, wherein the first endless flat belt material 31 is deformed as described above, optionally punched and folded over. The second endosseous ribbon 53 is also folded over. Subsequently, the merge is carried out as described above. That the endless flat belt materials 31, 53 and the endless profile sheet 35 are always sufficiently tensioned is determined by means known per se, e.g. dancing roles guaranteed.

Moreover, it is also within the scope of the invention, abzukanten the continuous profile sheet 35 and the second endless flat strip material 53 together only after merging and before bending. This is done e.g. by means of two stacking Abkantrollen that are formed analogous to the Abkantrollen for folding the Endlosprofilsblechs 35.

Furthermore, the turbulence insert 21 can also consist of two superimposed individual, profiled individual sheets, which are arranged so that they are supported against each other and preferably on the tube wall 10 and preferably form the honeycomb-shaped structure described above. The two individual sheets then each form a Einlagenbreitseitenwandung 69. The production of such a flat tube 4 is made e.g. by inserting the two individual sheets in the prefabricated flat tube. Conveniently, the individual sheets are soldered together at the contact points.

In addition, the two Einlagbreitseitenwandungen 69 of the turbulence insert 21 abutting each other need not be similarly profiled, but may, for example, also have different wave profiles or similar wave profiles with different dimensions. Preferably based In this case again the first vertex walls or vertices of the two opposite Einlagenbreitseitenwandungen 69 from each other, wherein not necessarily each vertex walls or each vertex must be supported on a apex walls or a vertex of the opposite Einlagenbreitseitenwandung 69.

In addition, irrespective of the type of profiling, not every first apex walls or each first apex of the two opposing Einlagenbreitseitenwandungen 69 on the pipe wall 10, in particular the respective pipe broad side wall 13, supported.

In addition, the turbulence insert 21 can also be slotted along the longitudinal side such that the longitudinal insert edges 77 do not abut one another but are spaced apart from one another. For example, the Endiosprofilblech 35 is not folded over during manufacture in the profile sheet longitudinal edges 36. The Endiosturbulenzeinlage 66 or the later turbulence insert 21 produced from this endless profile sheet 35 then has only one Einlagschmalseitenwandung 68.

Claims (28)

1. Flat tube (4) for a heat exchanger with a central longitudinal tube axis (15) and a tube wall (10) which has two oppositely lying broad sidewalls (13) and two oppositely lying narrow sidewalls (14) via which the broad sidewalls (13) are connected to each other, and with a turbulence insert (21) arranged on the inside of the tube wall (10),
   the turbulence insert (21) having two oppositely lying, profiled, broad sidewalls (69) which bear against each other in certain zones,
   each of the two broad sidewalls (69) of the insert having an undulating profile viewed in cross-section and each of the two broad sidewalls (69) of the insert having first and second crown walls (47,48), the first crown walls (47), viewed in a direction of the tube width (19) perpendicular to the longitudinal axis (15) of the tube and in a direction of the tube height (70) perpendicular to the longitudinal axis (15) of the tube and to the direction of the tube width (19), being arranged staggered with respect to the second crown walls (48), and the first and second crown walls (47,48), viewed in the direction of the tube width (19), being arranged alternately and in each case a first crown wall (47) being connected to a second crown wall by means of a lateral wall (49) which is preferably inclined, characterized in that
   the crown walls (47,48) and the lateral walls (49) extend longitudinally in a longitudinal tube direction (18) parallel to the longitudinal axis (15) of the tube,
   the first crown walls (47) of one broad sidewall (69) of the insert and the first crown walls (47) of the other broad sidewall (69) of the insert, viewed in the direction of the tube height (70), lying opposite each other in pairs and bearing against each other in pairs, the second crown walls (48) of one broad sidewall (69) of the insert and the second crown walls (48) of the other broad sidewall (69) of the insert lying opposite each other in pairs viewed in the direction of the tube height (70) and being spaced from each other in the direction of the tube height (70), the second crown walls (48) lying against an inner surface (12) of the tube wall (10) of the flat tube (4).
2. Flat tube (4) according to Claim 1, characterized in that the turbulence insert (21) is designed in the form of a flat tube and has a wall (67) with the two oppositely lying, profiled, broad sidewalls (69) and two oppositely lying, preferably planar, narrow sidewalls (68) via which the broad sidewalls (69) are connected to each other, the insert wall (67) being slitted preferably along the longitudinal side.
3. Flat tube (4) according to Claim 2, characterized in that the narrow sidewalls (68) of the insert lie against the narrow sidewalls (14) of the tube internally in a form-locked manner.
4. Flat tube (4) according to one of the preceding Claims 1 to 3, characterized in that the two broad sidewalls (69) of the insert, viewed in cross-section respectively, have a trapezoidal profile (46) or a sinusoidal undulating profile or a triangular profile or a rectangular profile, the first and second crown walls (47,48) as well as the lateral walls (49) being advantageously designed so as to be planar and plate-like and the first and second crown walls (47,48) extending preferably parallel to the broad sidewalls (13) of the tube.
5. Flat tube (4) according to Claim 4, characterized in that the first crown walls (47) of one broad insert sidewall (69) and the first crown walls (47) of the other broad insert sidewall (69) lie flat against each other in pairs.
6. Flat tube (4) according to Claim 4 or 5, characterized in that the second crown walls (48) lie flat against the tube wall inner surface (12) of the tube wall (10) of the flat tube (4).
7. Flat tube (4) according to one of the preceding claims, characterized in that the endless turbulence insert (66) has several first flow chambers (71) which are arranged next to each other in the transverse direction (70) of the tube and in each case are bounded by two oppositely lying second crown walls (48) and by the four lateral walls (49) adjoining them and which extend longitudinally in the longitudinal direction (18) of the tube.
8. Flat tube (4) according to one of Claims 4 to 7, characterized in that the turbulence insert (21) has a honeycomb profile.
9. Flat tube (4) according to Claim 8, characterized in that the first flow chambers (71) each have a hexagonal, in particular a uniform or regular hexagonal cross-section, the extension of the first flow chambers (71) in the direction of the height (70) of the tube preferably corresponding to the tube height so that the honeycomb-like structure forms a single row.
10. Flat tube (4) according to one of the preceding claims, characterized in that the flat tube (4) has several first and second flow chambers (71, 72) extending in the longitudinal direction (18) of the tube, in each case two second flow chambers (72) being arranged between two first flow chambers (71) and the two second flow chambers (72) arranged between two first flow chambers (71) being arranged above each other viewed in the direction of the height (70) of the tube.
11. Flat tube (4) according to one of the preceding claims, characterized in that the tube wall (10) is produced by means of roll forming and is welded preferably along the longitudinal side by means of a longitudinal welding seam (20) and the turbulence insert (21) is also preferably produced by means of roll forming and is welded along the longitudinal side by means of the longitudinal welding seam (20) so that the tube wall (10) and the turbulence insert (21) are welded together via the longitudinal welding seam (20).
12. Heat exchanger (1), characterized by flat tubes (4) according to one of the preceding claims.
13. Method for continuously producing flat tubes (4) with inner-lying turbulence insert (21), in particular for producing flat tubes (4) according to one of Claims 1 to 11, with the following method step:

    a) preparing a first endless flat strip of metallic material (31), in particular by means of continuous unreeling of the first endless flat strip of metallic material (31) from a first storage device (30), the method being characterized by the following method steps:

    b) shaping the first endless flat strip of material (31), in particular by means of two impression rolls (34a,34b) which are rotatable in opposite directions of rotation and between which the first endless flat strip of material (31) is guided in a conveying direction (32), so as to produce an endless profiled sheet (35) with two lateral longitudinal profiled-sheet edges (36) and two broad profiled-sheet sides (44,45);

    c) preparing a second endless flat strip of material (53) with two lateral longitudinal edges (56) and two broad sides (60,61), in particular by means of continuous unreeling of the second endless flat strip of material (53) from a second storage device (52);

    d) combining the endless profiled sheet (35) and the second endless flat strip of material (53) in such a way that they lie against each other along their broad side;

    e) continuously bending, preferably by means of roll forming, the second endless flat strip of material (53) together with the endless profiled sheet (35) so as to produce an endless flat tube (62) with a longitudinally slitted tube wall (10) with two oppositely lying longitudinal edges (75) and two oppositely lying broad sidewalls (13) as well as two oppositely lying narrow sidewalls (14) via which the broad sidewalls (13) are connected to each other, and a longitudinally slitted endless turbulence insert (66) with two advantageously oppositely lying, longitudinal or mating edges (77), the tube wall (10) enclosing the endless turbulence insert (66) and the endless turbulence insert (66) having two oppositely lying, profiled, broad sidewalls (69), which in certain zones bear against each other and in certain zones each lie against one of the two broad sidewalls (13) of the tube;

    f) joining, in particular welding, the two longitudinal edges (75) of the tube wall and preferably the two longitudinal edges (77) of the insert together;

    g) cutting to length the endless flat tube (62) into individual flat tubes (4).
14. Method according to Claim 13, characterized in that the endless profiled sheet (35), after shaping and before being combined, is folded at 90° at each of its two longitudinal edges (36) and preferably the second endless flat strip of material (53) before being combined is folded at 90° at each of its two lateral longitudinal edges (56), there being advantageously formed during folding of the endless profiled sheet (35) two lateral bridging walls (51) which are angled at 90° in relation to a transverse direction (37) of the profiled sheet and each have on the end side one of the two longitudinal profiled-sheet edges (36) and there being advantageously formed during folding of the second endless flat strip of material (53) two lateral bridging walls (57) which are angled at 90° in relation to a transverse direction (58) of the strip and each have on the end side one of the two longitudinal strip edges (56).
15. Method according to Claim 13 or 14, characterized by the production of an endless profiled sheet (35) which, relative to a profiled sheet mid-plane (65), has a central planar region (40), shaped regions (39,41) adjoining the central region (40) on both sides and outer planar regions (38,42) adjoining each of the two shaped regions (39,41), the first endless flat strip of material (31) advantageously being shaped so that the two shaped sections (39,41), viewed in cross-section, in each case have an undulating profile, in particular a trapezoidal profile (46) or a sinusoidal undulating profile or a triangular profile or a rectangular profile.
16. Method according to Claim 15, characterized in that the first endless flat strip of material (31) is shaped so that the shaped sections (39,41) in each case have first and second planar, plate-like and mutually parallel crown walls (47,48), the first crown walls (47), viewed in a transverse direction (37) of the profiled sheet and in a direction perpendicular to the conveying direction (32) and to the transverse direction (37) of the profiled sheet, are arranged staggered with respect to the second crown walls (48), the first and second crown walls (47,48), viewed in the transverse direction (37) of the profile, being arranged alternately and the first endless flat strip of material (31) being advantageously shaped so that in each case a first crown wall (47) is connected to a second crown wall (48) by means of inclined, preferably planar, plate-like lateral walls (49).
17. Method according to one of Claims 14 to 16, characterized in that, when being combined, the endless profiled sheet (35) is inserted into the second endless flat strip of material (53) and is placed thereon so that a second broad side (45) of the profiled sheet lies on a first broad side (60) of the strip and preferably the two bridging walls (51) of the endless profiled sheet (35) lie internally on the two bridging walls (57) of the second flat strip of material (53).
18. Method according to one of Claims 13 to 17, characterized in that the second endless flat strip of material (53) is bent in such a way that the longitudinally slitted tube wall (10) has a rectangular cross-section and advantageously the second endless flat strip of material (53) is bent in such a way that the two longitudinal edges (56) of the strip mate with each other and form the two oppositely lying longitudinal edges (75) of the tube wall and advantageously the two bridging walls (57) are arranged opposite each other and form one of the two narrow sidewalls (14) of the tube.
19. Method according to Claim 18, characterized in that the second endless flat strip of material (53) is angled at 90°, in particular upwards, on either side of a central mid-plane (76) of the strip perpendicular to the transverse direction (58) of the strip, the bending regions being uniformly spaced from the strip mid-plane (76).
20. Method according to one of Claims 13 to 19, characterized in that the endless profiled sheet (35) is bent in such a way that the two longitudinal edges (36) of the profiled sheet mate with each other and form the longitudinal edges (77) of the insert.
21. Method according to one of Claims 14 to 20, characterized in that the endless profiled sheet (35) is bent in such a way that the two bridging walls (51) are arranged opposite each other and advantageously are oriented horizontally.
22. Method according to one of Claims 15 to 21, characterized in that endless profiled sheet (35) is angled at 90°, in particular upwards, on either side of the mid-plane (65) of the profiled sheet in the central planar section (40), the bending regions being uniformly spaced from the mid-plane (65) of the profiled sheet.
23. Method according to one of Claims 15 to 22, characterized in that, during bending, the two shaped sections (39,41) are folded onto each other in particular in such a way that the first crown walls (47) of the first shaped section (39) and the first crown walls (47) of the second shaped section (39) are situated opposite each other in pairs, in particular lie against each other in pairs and the second crown walls (48) of the first shaped section (39) and the second crown walls (48) of the second shaped section (39) also are situated opposite each in pairs, but are spaced from each other.
24. Method according to one of Claims 13 to 23, characterized in that the two longitudinal edges (75) of the tube wall and the two longitudinal edges (77) of the insert are welded together by means of formation of a longitudinal welding seam (20) so that the tube wall (10) and the endless turbulence insert (66) are welded together via the longitudinal welding seam (20).
25. Method according to one of Claims 13 to 24, characterized in that the longitudinal edges (77) of the insert are soldered together owing to the effect of the heat during welding of the longitudinal edges (75) of the tube wall.
26. Method according to one of the Claims 13 to 25, characterized in that, owing to the effect of the heat, the endless turbulence insert (66) is soldered in certain regions to the tube wall (10) during welding.
27. Apparatus (22) for the continuous production of flat tubes (4) with an inner-lying turbulence insert (21) according to one of Claims 1 to 11 and according to the method according to one of Claims 13 to 26, characterized by:

    a) a turbulence insert prefabrication device (23) with a shaping device (33) having means for shaping a first endless flat strip of metallic material (31) so as to produce an endless profiled sheet (35) with two lateral longitudinal edges (36) and two broad sides (44,45);

    b) means for preparing a second endless flat strip of metallic material (53) with two lateral longitudinal edges (56) and two broad sides (60,61);

    c) a combining device (25) with means for combining the endless profiled sheet (35) and the second endless flat strip of material (53) so that they lie against each other on their broad side;

    d) several bending devices (26a,b) arranged behind one another in relation to a conveying direction (32), for continuously bending, preferably by means of roll forming, the second endless flat strip of material (53) together with the endless profiled sheet (35) so as to produce an endless flat tube (62) with a longitudinally slitted tube wall (10) with two oppositely lying longitudinal edges (75) and a longitudinally slitted endless turbulence insert (66) with two longitudinal or mating edges (37) lying preferably opposite each other, the tube wall (10) enclosing the endless turbulence insert (66);

    e) a joining device, in particular a welding device (27), for joining together the two longitudinal edges (75) of the tube wall and preferably the two longitudinal edges (77) of the insert;

    f) and a dividing device (29) for dividing the endless flat tube (62) into individual flat tubes (4).
28. Apparatus according to Claim 27, characterized in that the shaping device (33) has two rotatably mounted impression rolls (34a, 34b) arranged over each other in the vertical direction, for impressing the first endless flat strip of metallic material (31).

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