DE102012024179A1 - Heat exchanger tube, heat exchanger tube assembly and method of making same - Google Patents

Abstract

A tube (2) for use in a tube arrangement (1) for a heat exchanger comprises a flat area (3) which is arranged away from a tube end. The flat area (3) comprises wide, flat, parallel tube sides (12) which are connected by narrow sides, so that the tube (2) is relatively thin in one direction. A cylindrical portion (4, 5) extends from the end of the tube and a transition portion (6) connects the cylindrical portion (4, 5) and the flat tube portion (3). The geometry of the transition region (6) provides a bending strength at the intersection between the flat tube region (3) and the transition region (6).

Description

The present invention relates generally to tubes and to fin and tube assemblies for heat exchangers and to methods of making same.

Large-area heat exchangers are known, which include standalone, single replaceable pipe assemblies, and a pipe for conveying a first liquid and a second heat transfer surface area for a second liquid to transfer heat to or from the first liquid transfer. As examples, heat exchangers of this type, which function as heavy duty radiators to transfer waste heat from an engine coolant to the air, are known in the art U.S. Patent No. 3,391,732 from Murray and U.S. Patent No. 4,236,577 described by Neudeck. The tubing assemblies used in these heat exchangers have a central fin area for heat exchange and non-ribbed cylindrical end areas for insertion into grommets.

Heat exchanger tube assemblies of the type described above are constructed substantially of copper with expanded air side surfaces in the rib area which is brazed to a tube. Copper offers the advantage of high thermal conductivity, favorable manufacturability and good strength and service life. But the steadily rising copper price has led to a demand for alternative low-cost materials.

Aluminum has replaced copper as the preferred construction material in other heat exchangers (for example, automobile radiators and commercial radiators), but has not successfully replaced copper in high performance heat exchangers of this type. Aluminum has substantially lower strength than copper, which raises life concerns. This is particularly problematic in applications where individual piping assemblies must be removed and deployed in an area where damage is likely to occur during this handling. In addition, the bonding of copper components requires substantially higher temperatures than the brazing of copper and leads to manufacturing or manufacturing difficulties. Thus, there is still a lot to improve. It is therefore an object of the present invention to provide a tube for a heat exchanger, which allows overcoming the disadvantages of the prior art. The solution of this object is achieved by the features of independent claims 1 and 12. The dependent claims have advantageous developments of the invention to the content.

According to one embodiment of the invention, a tube assembly for a heat exchanger comprises a tube having a flat portion with spaced wide tube sides joined by opposing narrow tube sides. The tube assembly further includes two fin assemblies, each having peaks and troughs connected by flanks and two substantially planar side plates. Troughs of a fin assembly are connected to one of the wide tube sides and wave crests of this fin assembly are joined to an area of one of the side panels. Wave troughs of the other fin assembly are connected to the other wide tube side and wave crest of this fin assembly with a surface of the other side plate.

In some embodiments, the tube includes cylindrical portions at longitudinal ends of the tube with the flat portion disposed between the cylindrical portions. In some embodiments, the tube, rib assemblies, and side panels are joined by brazed joints, and in some embodiments are formed from one or more aluminum alloys. According to some embodiments, the thickness of the wide tube sides is at least twice as thick as the side plates.

According to another embodiment of the invention, a tube assembly for a heat exchanger comprises a fluid flow conduit extending longitudinally over at least a portion of the tube assembly. The fluid flow conduit has a major dimension and a minor dimension, both being perpendicular to the longitudinal direction and the minor dimension being substantially smaller than the major dimension. A continuous tube wall encloses the flow line. Two substantially planar side plates are equidistant from the continuous tube wall in the direction of the small dimension and connected to the tube wall by wave structures or thin webs.

In some embodiments, the continuous tube wall has a tube wall center of gravity moment of inertia with respect to an axis in the major dimension direction. In some embodiments, the center of mass moment of inertia of the tube assembly with respect to this axis is at least five times greater than the tube wall center of gravity momentum, and in some embodiments, at least ten times greater.

In some embodiments, a first cylindrical tube portion having the continuous tube wall at a first end of the Flow line and a second cylindrical tube portion connected to the continuous tube wall at a second end of the flow line. In some of these embodiments, the outer circumference defined by the continuous tube wall is greater than the outer circumference of at least one of the cylindrical tube portions.

According to another embodiment of the invention, a method of manufacturing a heat exchanger assembly includes providing a tube, first and second corrugated fin assemblies, and first and second substantially planar side sheets. The first corrugated fin assembly is disposed between the first side plate and a first wide and flat side of the tube, and the second corrugated fin assembly is disposed between the second side plate and a second wide and flat side of the tube. A compressive force is applied to opposite sides of the side panels to contact peaks and troughs of the rib assemblies with the side panels and the wide and flat sides, and the brazed joints become between the first rib assembly and the first side panel, the first rib assembly and the first wide and flat side, the second rib assembly and the second side plate and the second rib assembly, and the second wide and flat sides created.

In some of these embodiments, the tube, fin assemblies and side panels are elevated to a temperature in a vacuum environment to produce the brazed joints. In other embodiments, they are elevated to a temperature in a controlled inert gas environment. In some embodiments, providing the tube, the fin assemblies, and side panels includes providing a material brazed with braze.

In some embodiments, the compressive force is transmitted through a first baffle adjacent to the first side panel and through a second baffle adjacent to the second side panel. In some of these embodiments, the baffles have a coefficient of thermal expansion that substantially matches that of the tube, the side plates, and the fin assemblies. In some embodiments, the first baffle is one of a plurality of baffles adjacent to the first side baffle.

According to another embodiment of the invention, a method of manufacturing heat exchanger tube assemblies includes providing a plurality of tubes, a plurality of corrugated fin assemblies, and a plurality of substantially planar side plates. Each of the tubes is disposed between pairs of corrugated fin assemblies and each of the corrugated fin assemblies between one of the tubes and one of the side plates. The tubes, corrugated fin assemblies and side panels are arranged in a stack. Dividers are disposed between adjacent pairs of side panels and adjacent the side panels at the extreme ends of the stack. A compressive load is applied to the stack in the stacking direction. Brazed joints are created at contact points between the corrugated fin assemblies and the tubes and between the corrugated fin assemblies and the side plates, and the brazed tube assemblies are removed from the baffles.

In some of these embodiments, the tubes, fin assemblies and side panels are elevated to a temperature in a vacuum environment to produce the brazed joints. In other embodiments, they are elevated to a temperature in a controlled inert gas environment. In some embodiments, providing the tubes, fin assemblies, and side panels includes providing a material that is coated with a braze.

According to another embodiment of the invention, a tube for a heat exchanger comprises a first cylindrical portion extending from a first end of the tube, a second cylindrical portion extending from a second end of the tube, and a flat portion extending between the two Ends is arranged and has two wide and flat, parallel spaced sides, which are connected by two relatively short sides. Transition areas are located between each of the cylindrical areas and the flat area. The intersections of the transition regions and each of the wide and flat sides of the tube define curved paths.

In some of these embodiments, the two relatively short sides have an arcuate profile. In some embodiments, each of the curved paths includes an apex located at a median plane of the tube, and in some of these embodiments, an arcuate path segment is disposed at the tip.

In some embodiments, the transition region adjacent to one of the cylindrical regions extends over a length that is at least equal to the diameter of that region. In some embodiments, the outer circumference of the flat portion of the tube is larger than the outer circumference of at least one of cylindrical areas, and in some embodiments it is at least 25% larger.

In some embodiments, the flat tube portion defines a tube major dimension between outermost points of the two relatively short sides, and each of the curved paths is longer than the tube major dimension. In some embodiments, the tube is made of an aluminum alloy.

According to another embodiment of the invention, a heat exchanger tube is formed from a round tube by reducing a diameter of the round tube in a first region of the round tube and a second region adjacent to the first region is flattened to have two spaced apart wide and flat sides in the second Define area. In some embodiments, the first regions terminate at one end of the tube. In some embodiments, the second area is flattened after reducing the diameter of the first area.

In some embodiments, the diameter of the first region is reduced by a swaging operation. In some embodiments, the second region is flattened by compression to that region in a stamping die. In some embodiments, the tube is made of an aluminum alloy.

In some embodiments, a mandrel is inserted into the tube prior to flattening of the second region and removed from the tube after flattening of the second region.

In some embodiments, the diameter of a third region of the round tube is reduced, wherein the third region is adjacent to the second region. In some embodiments, the third region terminates at a second end of the tube. In some embodiments, the second area is flattened after reducing the diameter of the third area.

Further details, advantages and features of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings. It shows:

1 a perspective view of a heat exchanger tube assembly according to an embodiment of the invention.

2 a plan view of the heat exchanger tube assembly of 1 ,

3 a detailed view of the area of 2 which is bounded by the line III-III.

4 a plan view of the heat exchanger tube assembly of 1 ,

5 an exploded perspective view of the heat exchanger tube assembly of 1 ,

6 a plan view of a stack of heat exchanger tube assemblies, which are made according to an embodiment of the invention.

7 a plan view of certain components of the stack of 6 ,

8th a perspective view of a heat exchanger tube according to an embodiment of the invention.

9 a partial perspective view of a heat exchanger tube according to the prior art.

10 a partial view along the lines XX of 8th ,

11 a partial view along the lines XI-XI of 8th ,

12 a partial perspective view of the partially formed tube of 8th ,

13A and 13B schematic views of a training or forming process to the pipe of 8th manufacture.

Before any of the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of the components illustrated in the following description or illustrated in the accompanying drawings. The invention is suitable for other embodiments and is used and executed in different ways. It is also to be understood that the phraseology and terminology used herein are for the purpose of description and are not to be considered as limiting. The use of "comprising,""having," or "having," and variations thereof, as used herein, includes all terms and equivalents thereof noted below and additional terms. Unless otherwise specified, the terms "arranged,""connected,""stored," and "coupled" and variations thereof are used broadly and include both direct and indirect arrangements, connections, bearings, and couplings. Further, "connected" and "coupled" are not on limited physical or mechanical connections or couplings.

A heat exchanger tube arrangement 1 according to one embodiment of the invention is in 1 to 5 shown. This pipe arrangement 1 can be used as one of many individual tubes of a heat exchanger, for example a radiator, in large heavy equipment, such as excavators, mine trucks, gensets, etc. It should be understood, however, that the tube assembly 1 can be used in heat exchangers of different types and sizes.

The pipe arrangement 1 includes a tube 2 that is from a first end 7 to a second end 8th extends. The pipe 2 defines a fluid flow line, wherein a fluid (eg, a coolant or engine coolant) through the tube assembly 1 is transported. As an example, the tube assembly 1 be used in a Kühlmittelradiator to reject or waste heat from a coolant flow when the flow of coolant through the pipe 2 from one of the ends 7 . 8th to the other of the ends 7 . 8th flows or flows.

The pipe 2 includes a flat area 3 that between the ends 7 . 8th is arranged. The flat area 3 (best by 11 described) includes first and second parallel, wide and flat or planar sides 12 , The wide and flat sides 12 are spaced from each other and by two opposing, spaced narrow tube sides 15 connected. While the narrow tube sides 15 are shown with arcuate profile in the exemplary embodiment, the narrow tube sides 15 in other embodiments may be straight or from another profile shape. The two broad and flat sides 12 and the two narrow sides 15 define together a continuous pipe wall 25 the fluid flow conduit having an interior defining an open space to the continuous tube wall 25 to the flow of a liquid through the pipe 2 to enable. While not illustrated in the exemplary embodiment, in some instances it is advantageous to provide surface enhancement or flow swirling features within the flowline to increase the heat transfer rate between a liquid flowing through the tube 2 and the pipe wall 25 goes through to improve.

In terms of 11 indicates the flat area 3 of the pipe 2 a small pipe dimension d1, which is the distance between outward surfaces of the two wide and flat sides 12 is defined, and a pipe main dimension d2, as the distance between outermost points of the two narrow sides 15 is defined. In some highly desirable embodiments, the major dimension d2 is several times larger than the small dimension d1. For example, the major dimension of the exemplary embodiment is nine times greater than the small dimension.

The pipe arrangement 1 further includes two coiled rib assemblies 10 that go along the flat area 3 are arranged. The rib arrangements 10 include several flanks 16 through the crest 18 and hollows 17 are connected in an alternating manner, so that each of the rib arrangements 10 has an approximate sinusoidal shape (best in 3 to see). The rib arrangements 10 can be clear or simple as in 3 or may include additional features to enhance heat transfer, structural strength, life, or combinations thereof. For example, in some embodiments, the rib assemblies 10 Ventilation slots, bumps, slots, lances or other known features include heat transfer and / or structural stiffness of the flanks 16 to improve. In other embodiments, a butt edge may be at one or both of the ends of a rib assembly 10 leading to the narrow tube sides 15 are adjacent, are provided. This edging can be a particularly advantageous resistance to damage caused by colliding with boulders or other debris.

Thin side plates 11 are also in the pipe arrangement 1 contain. These side plates 11 are to the opposite wide and flat sides 12 of the pipe 2 parallel and through the rib arrangements 10 equidistant on each side. Consequently, the flanks see 16 , Vertex 18 and hollows 17 the rib assemblies a plurality of thin webs in front of the side plates 11 from the continuous pipe wall 25 to arrange with distance. The side panels 11 are substantially planar, but may include features such as curved edges to aid in increased stiffness and / or placement.

The spaces between the flanks 16 provide flow channels for a liquid to transfer heat to the liquid passing through the tube 2 permitting, so that heat can be exchanged between the two liquids. Ambient air may, for example, be directed through the flow channels to the coolant of an engine coolant jacket passing through the pipe 2 goes through, to cool. It goes without saying that different other liquids in heat transfer reference using the tube assembly 1 can be made. Each of the flow channels between the flanks 16 is further through one of the hollows 17 and vertex 18 and through one of the flat sides 12 of the pipe 2 and the substantially flat side panels 11 Are defined. By completely confining the flow channels in this way, the liquid passing through these channels is prevented from prematurely leaving the channels, thereby improving the heat transfer performance.

The pipe 2 , Rib arrangements 10 and side panels 11 are preferably joined together to form a monolithic structure to provide good thermal contact between the heat transfer liquids as well as good structural integrity. While different materials can be used to pipe the arrangement 1 to construct the pipe 2 , Rib arrangements 10 and side panels 11 formed in preferred embodiments of metals with a high thermal conductivity, such as aluminum, copper and the like. The components can be connected together to the pipe assembly 1 through various processes involving brazing, soldering, gluing, etc., to form.

In order to promote good heat transfer between the fluids, it can be used for the rib arrangements 10 and side panels 11 be advantageous over the entire main dimension d2 of the flat area 3 to extend. In some cases it may be advantageous to use the rib arrangements 10 and side panels 11 something about the outer edges of the narrow tube sides 15 To expand to protect the fluid flow line from damage by colliding with stones or other debris.

Even with the inclusion of very thin side plates 11 It was found that they are the pipe assembly 1 very stiffening, especially with respect to bending around the center of gravity axis at the main pipe dimension d2. The rib arrangements 10 see a very small rigidity in this direction due to their entangled nature, so that the continuous tube wall 25 in the absence of side panels 11 offers the only resistance when bending around the center of gravity. Due to the relatively small small dimension d1 of the flat tube region 3 is the resistance to bending around the center of gravity solely through the continuous tube wall 25 quite small and the distance of the side panels 11 away from the center of gravity axis by a distance substantially greater than the small dimension d1 offers a significant advantage.

The influence of the side panels 11 on the flexural rigidity of the tube assembly 1 around the center of gravity axis at the main pipe dimension d2, by comparing the center of gravity moment about this axis of the pipe assembly 1 around with that of the pipe 2 be determined quantitatively alone (in the rib arrangements 10 It can be assumed that they provide no contribution or contribute to the moment of inertia, except by maintaining the displacement of the side panels 11 from the flat sides 12 of the pipe 2 ). For an exemplary embodiment having a tube wall thickness of 0.8 mm, a side plate thickness of 0.25 mm, a rib assembly height of 6.55 mm, a small dimension of 3.7 mm, and a major dimension of 23.27 mm, the centroid moment of inertia becomes around Pipe main dimension axis around for the pipe assembly and the pipe alone respectively calculated to be 925 mm ⁴ and 76 mm ⁴ . In other words, the centroid moment of inertia of the tube assembly about the tube major dimension axis is about twelve times that of the tube itself. In preferred embodiments, the centroid moment of inertia of the tube assembly about the tube major dimension axis is at least five times that of the tube itself, and very much preferred Embodiments at least ten times as large. This is especially desirable when the pipe 2 of a material having a relatively small modulus of elasticity, for example, aluminum alloys.

The pipe 2 The exemplary embodiment further includes a first cylindrical portion 4 that's the first end 7 is adjacent, and a second cylindrical portion 5 , the second end 8th is adjacent, with the flat area 3 which is disposed between the first and second cylindrical portions. These cylindrical areas 4 . 5 allow a reliable and leak-free insertion of the pipe assembly 1 in receiving spouts, which are arranged in opposite heads or upper parts of a heat exchanger (not shown). In order to maximize the size of the tube available for effective heat transfer, the length of the cylindrical end portions is preferably maintained to a minimum and the length of the flat portion 3 is preferably 90% or more of the entire length of the tube 2 , A circumferential bead 9 is on the cylindrical area 5 of the exemplary embodiment provided for the downward movement of the tube assembly 1 to limit, if it is arranged vertically in a heat exchanger.

While the embodiments illustrated in the accompanying figures cover the cylindrical end portions at both ends of the tube, it will be understood that in some examples a pipe arrangement 1 without one or both cylindrical end regions 4 . 5 can be. If these cylindrical end portions are not included, the respective female grommets may be provided with female openings corresponding to the profile of the continuous tube wall 25 in the shallow area 3 correspond.

In certain preferred embodiments of the invention, a heat exchanger tube assembly 1 by producing brazed joints between an aluminum tube 2 , first and second ribbed aluminum rib assemblies 10 and first and second aluminum side surfaces 11 produced. The first corrugated fin arrangement 10 is between the first side plate 11 and a first broad and flat side 12 of the pipe 2 arranged while the second corrugated fin arrangement 10 between the second side plate 11 and a second wide and flat side 12 of the pipe 2 is arranged. The arrangement is compressed to the vertices 18 and hollows 17 the rib arrangements 10 with the adjacent parts in contact, so that brazed joints can be formed at contact points.

A brazing alloy with a melting temperature that is less than the melting temperatures of the pipe 2 , Rib arrangements 10 and side panels 11 is used to produce brazed joints. Such a filler is typically aluminum with small amounts of other elements (for example, silicon, copper, magnesium and zinc) added to reduce the melting temperature. The braze can advantageously be provided as a layer on one of several of the hard-to-solder components. In some embodiments, both sides of the sheet material used to form the corrugated fin assemblies 10 is coated with the braze, thereby providing the required braze at all points of contact where brazed joints are desired, while avoiding having a braze at locations where joins are not necessary or undesirable.

While many procedures can be used to control the temperature of the pipe 2 , the rib formations 10 and the side panels 11 In order to melt the braze and form the brazed joint, vacuum brazing and controlled atmosphere brazing are two particularly preferred methods. In vacuum brazing, the assembled parts are placed in a closed furnace and essentially all of the air is removed to create a vacuum environment. In this process, the magnesium present in the alloys is released as the parts are heated and serves to dissolve the oxide layer present on the outer surfaces of the components to allow the molten braze to bond to the present aluminum , The oxide layer is prevented from reforming and interfering with the metallurgical bond by the lack of oxygen in the vacuum environment.

In controlled atmosphere soldering, a flux is applied to the components before heating. Warming of the parts occurs in an inert gas environment to prevent reformation of the oxide layer after the flux reacts and displaces the oxide layer present on the mating surfaces of the parts. With the extruded oxide layer, the molten braze joins with the present aluminum to produce the brazed joint.

It may be particularly desirable to have more of the tube assemblies 1 one after the other, especially brazing, to increase throughput in a manufacturing environment. 6 illustrates a method according to an embodiment of the invention, wherein four tube assemblies 1 be produced simultaneously. It will be understood that the same method may be used to produce more than four or less than four of the tube assemblies, respectively.

In the embodiment of 6 are pipes 2 , ribbed ribs 10 and substantially flat side panels 11 intended. Each of the pipes 2 is between pairs of ribbed ribs 10 and each of the corrugated fin assemblies 10 between one of the pipes 2 and one of the substantially planar side panels 11 arranged. The side panels 19 are between adjacent pairs of substantially planar side panels 11 arranged. The pipes 2 , ribbed ribs 10 and substantially flat side panels 11 are in a pile 26 arranged. Additional dividers 19 are adjacent to the substantially planar side panels 11 at the extreme ends of the stack 26 arranged and a compressive load is placed on the stack 26 applied in the stacking direction to the vertices 18 and hollows 17 the corrugated fin arrangements with the adjacent side panels 11 and the broad and flat sides 12 the pipes 2 to bring into contact.

For a uniform or even pressure load on the stack 26 can muster bars 21 with a high rigidity (for example structural steel channels) on the extreme ends of the stack 26 be used. The compressive load can be maintained after being applied to the stack by the use of metal bands or metal strips 22 that the pile 26 in several places, was applied. The Stripes 22 be over the bars 21 tightened or contracted while the stack 26 is compressed, leaving tension in the strip 22 maintains the pressure load. After this assembly, the stack becomes 26 arranged in a soldering oven to the individual pipe arrangements 1 to create. The stack 26 is heated within the furnace to a temperature suitable for melting the brazing alloy, after which the stack 26 is cooled to re-solidify the molten brazing alloy, whereby brazed joints are produced at the contact points. After cooling, the individual pipe arrangements 1 , which were soldered to individual monolithic structures, from the dividing plates 19 be removed. The dividers 19 can be provided with a layer to any metallurgical connection between the dividing plates 19 and the side plates 11 Otherwise, this undesirable connection may occur at soldering temperature, even without the presence of braze.

When the pile 26 is heated to a soldering temperature, a thermal expansion of the metallic materials in the stack 26 occur. In aluminum brazing, the components are typically heated to a brazing temperature of 550 ° C to 650 ° C. This temperature range is substantially higher than that used to braze copper components, and hence the thermal expansion caused by the components of the tube assemblies 1 is detected during the bonding process, substantially larger when the components are made of aluminum than if they are made of copper.

Investigations conducted in the context of the invention have shown that it must be ensured during the soldering process that the rib arrangements 10 can not be deformed by heating to soldering temperature and cooling down to ambient temperature. Unlike the traditional manufacture of brazed aluminum radiators, which includes many rows of tubes and fin assemblies joined together to form a monolithic brazed core, the flanks are 16 the rib arrangements 10 shear forces caused by thermal expansion differences between the components of the pipe assemblies 1 and the dividers 19 be prone to deformation. In some embodiments of the invention, this problem is overcome by a common match of the coefficient of thermal expansion of the baffles 19 with the pipes 2 , Rib arrangements 10 and side plates fixed. This can be done by forming the dividers 19 from similar aluminum alloys or from another material having a similar rate of thermal expansion.

Alternatively or additionally, many individual dividers 19 between each adjacent pipe assembly 1 used as in 7 shown. recesses 20 are between adjacent sheets of the individual dividers 19 intended. In the case where dividers 19 made of a material with a substantially different thermal expansion coefficient than the materials making up the tubes 2 , Rib arrangements 10 and side panels 11 can be constructed, the recesses can be constructed 20 during heating and cooling of the stack 26 increase or decrease, causing the deformation of the rib assemblies 10 is substantially reduced, which otherwise could result from the mismatch in thermal expansion coefficients. The recesses 20 serve as breaks to prevent the accumulation of thermal expansion induced by deformation, so that any such deformation occurs on discrete contact areas below each of the individual baffles 19 is limited. This in 7 illustrated manufacturing method may be particularly advantageous if a more temperature-resistant material, such as stainless steel, for the dividing plates 19 is used and the components of the pipe arrangements 1 made of aluminum.

The pipe 2 will now be more detailed with special reference to the 8th to 13 discussed. As previously described, the embodiment of the tube includes 2 , this in 8th is shown, a flat tube area 3 placed between a first cylindrical tube area 4 and a second cylindrical tube portion 5 is arranged. The first cylindrical pipe section 4 extends from the first end 7 of the pipe 2 while the second cylindrical tube area 5 from the second end 8th of the pipe 2 extends. Transition areas 6 are between the flat area 3 and each of the cylindrical areas 4 and 5 arranged. The transition areas 6 see a uniform continuous flow path for a liquid passing through the pipe 2 passes, as well as avoiding locations of mechanical stress concentration in the tubing.

As detailed in the partial sectional view of 10 shown, extends a transition region 6 over a length L, extending from one place 27 near the end 7 of the pipe 2 is, up to a point 14 that are far from the end 7 is, tense. The length L is preferably at least equal to the diameter of the cylindrical end portion 4 although in some alternative embodiments they are in the Dimension can be smaller than the diameter of the respective end region. As in 8th As can be seen, the broad and flat side extends 12 about the places 14 at both ends, leaving at least one area of the wide and flat side 12 along the pipe 2 between the bodies 27 and 14 is arranged, which is the beginning and the end of a transition area 6 define.

In preferred embodiments, the intersections of the transition regions define 6 and the broad and flat sides 12 of the flat tube area 3 curved paths or paths 13 , These curved paths 13 see a favorable stiffening of the flat area 3 of the pipe 2 with respect to a bending moment around the pipe main dimension axis. For comparison purposes is a tube 102 in the prior art 9 and includes a flat area 103 that with a cylindrical area 104 by means of a transitional area 106 connected is. The intersection of the transition area 106 and the flat area 103 define a straight path 113 on the broad and flat side 112 of the flat area 103 , The straight path 113 extends into the pipe main dimension and bending around the main dimension axis is quite simple. This may occur during the installation and / or removal of a pipe assembly containing the pipe 102 from a heat exchanger, may be particularly disadvantageous if such installation and removal often applies bending moments of this type to the pipe. This problem is particularly exacerbated when the pipe is constructed of a material of fairly low strength, such as annealed aluminum.

Investigations carried out in the context of the invention have shown that the curved path 13 provides a substantial stiffening effect to withstand a bending moment of the aforementioned type and prevents kinking or other damage to the pipe 2 during installation, removal or other handling of the pipe 2 or a pipe arrangement 1 with a pipe 2 , While an advantage or benefit can be derived from any non-linear or non-straight path, it may be for the way 13 be very advantageous to be defined by a series of connected arcuate path segments.

In the exemplary embodiment, each curved path includes 13 an apex or apex which is at the approximate median plane of the tube 13 is arranged so that the tip at one point 14 along the way 13 , the farthest from the end 7 (in the case of the transition area between the flat area 3 and the first cylindrical end 4 ) or from the end 8th (in the case of the transition area between the flat area 3 and the second cylindrical end 5 ) is arranged. The way 13 preferably includes an arcuate path segment at the tip so as to avoid stress concentrations at the tip.

In some preferred embodiments, the outer circumference (ie, circumference) of at least one of the two cylindrical regions 4 . 5 smaller than the outer circumference of the continuous pipe wall 25 in the shallow area 3 , This advantageously allows a relatively large heat transfer surface area per unit length in the flat area 3 without having a respective large diameter at one or both of the ends 7 . 8th is required. A smaller diameter at the ends may be advantageous if it can accommodate a smaller distance from adjacent pipe assemblies and, for example, requires less sealing area at the ends. In some preferred embodiments, the outer circumference of the flat area exceeds 3 the outer circumference of at least one of the two cylindrical end regions by at least 25%.

Heat exchangers with liquid-conveying tubes having a flattened profile along their entire length are known in the art, having been used for decades as radiators or the like. Flat tubes of this type are usually constructed in one or two ways. They are extruded and / or deep-drawn and cut into individual lengths either in the flat form from a material billet or they are cut into rolls in a tube mill by forming the sheet shape into a round shape, seam welding, flat rolls to flat tube shape and cutting in individual pipe lengths generated.

For pipes, such as the pipe 102 according to the prior art ( 9 ) with a flattened area 103 and a cylindrical end portion 104 , the ends of the flat tube are formed in a cylindrical shape around the cylindrical end portion 104 and the transition area 106 to build. This process can be performed quickly and easily if the tube is constructed of highly deformable material, such as copper, and only the outer ends of the tube 2 are to be formed. However, this method is not for obtaining a transition range 6 as described above.

The transition areas 6 can by initially forming the tube 2 in a round shape with an outer diameter equal to the desired outer circumference or outer circumference of a continuous tube wall 25 in the shallow area 3 is to be trained. In terms of 12 Next are the ends of the round tube or round tube 2 reduced in diameter to the cylindrical ends 4 and 5 and a tapered transition area 6 ' between the ends 4 . 5 and the middle area 3 ' that keeps the original round shape training. This diameter reduction can be carried out, for example, by die forging the pipe ends. In some preferred embodiments, the ends are reduced in diameter by at least 20% to the desired outer circumference ratio between the flat region 3 and the cylindrical end portions 4 . 5 to reach.

As in 13A and 13B shown, the profiles of the flat area 3 of the pipe 2 by forming this area 3 ' of the pipe 2 between a first forming die half 22 and a second forming die half 23 To be defined. The pipe 2 gets between the tool halves 22 . 23 used when the tool is in an open position, ie, when the two tool halves are separated, as in FIG 13A shown. With the tube so arranged 2 closes the tool so as to be in the closed position of 13B to be, making the flat area 3 of the pipe 2 to the smaller dimension d1 and the main dimension d2 is formed. Optionally, a thorn 24 inside the pipe 2 be arranged before the forming process, a buckling or other undesirable deformation of the wide and flat tube walls 12 during the forming process. The thorn 24 can after application of the pipe 2 be removed after the forming process is completed. The geometry of the transition areas 6 can by including complementary negative representations of the geometry at the contact surfaces of the tool halves 22 and 23 be prepared so that the desired geometry of the transition areas 6 in the pipe 2 is formed during the forming process.

Although the present invention has been described in the preferred embodiments described above, it is not limited to those embodiments described above. Variations and variations of the embodiments described above will appear to those of ordinary skill in the art in light of the above teachings. They are defined by the following claims.

The embodiments described above and illustrated in the figures are given by way of example only and do not limit the concepts and principles of the present invention. As such, it will be understood by one of ordinary skill in the art that various changes are possible.

In summary, the following can be stated:
A pipe 2 for use in a pipe arrangement 1 for a heat exchanger comprises a flat area 3 which is arranged away from a pipe end. The flat area 3 includes wide, flat, parallel tube sides 12 that are connected by narrow sides, leaving the pipe 2 in one direction is relatively thin. A cylindrical area 4 . 5 extends from the end of the pipe and a transition area 6 connects the cylindrical area 4 . 5 and the flat tube area 3 , The geometry of the transition region ( 6 ) creates a bending strength at the point of intersection between the flat tube region ( 3 ) and the transition area 6 ,

In addition to the above written disclosure of the invention is hereby supplementary to the drawings in 1 to 13B Referenced.

LIST OF REFERENCE NUMBERS

1

pipe arrangement

2, 102

Tube or heat exchanger tube or round tube

3, 103

flat or even area

3 '

the central region

4

1. cylindrical tube area / end area

5

2nd cylindrical tube area / end area

6, 106

Transition area

6 '

tapered transition area

7

first end

8th

second end

9

bead

10

fin assembly

11

flat side plate

12, 112

wide and flat or even sides

13

curved path or railway

14, 27

1st and 2nd place

15

narrow tube sides

16

flanks

17

Trough or wave trough

18

Vertex or wave crest

19

Divider

20

recess

21

rods

22

Metal bands or strips

22

1. forming half

23

2. Forming tool half

24

mandrel

25

continuous pipe wall

26

stack

104

cylindrical pipe or end area

113

straight path or train

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 3391732 [0002]
• US 4236577 [0002]

Claims (20)

Pipe ( 2 ) for a heat exchanger, comprising: - a first cylindrical region ( 4 ) extending from a first pipe end ( 7 ) extends; A second cylindrical area ( 5 ) extending from a second pipe end ( 8th ), which is the first pipe end ( 7 ) is opposite; - a flat tube area ( 3 ) between the first and second ends ( 7 . 8th ), wherein the flat tube region ( 3 ) two wide and flat, parallel spaced sides ( 12 ) connected by two relatively short sides; - a first transitional area ( 6 ) located between the first cylindrical area ( 4 ) and a first end ( 7 ) of the flat tube region ( 3 ), which is close to the first cylindrical region ( 4 ) is arranged; and - a second transition region ( 6 ) located between the second cylindrical region ( 5 ) and a second end ( 8th ) of the flat tube region ( 3 ), which is close to the second cylindrical region ( 5 ), the intersections of each of the first and second transition regions ( 6 ) and each of the wide and flat sides ( 12 ) curved paths ( 13 ) form. Pipe ( 2 ) according to claim 1, wherein the two relatively short sides have an arcuate profile. Pipe ( 2 ) according to claim 1 or 2, wherein each of the curved paths ( 13 ) comprises a tip which is at a median plane of the tube ( 2 ) is arranged. Pipe ( 2 ) according to one of claims 1 to 3, wherein each of the curved paths ( 13 ) comprises an arcuate path segment at the tip. Pipe ( 2 ) according to one of claims 1 to 4, wherein the first cylindrical region ( 4 ) forms a tube diameter and the first transition region ( 6 ) in the axial tube direction over a length which is at least equal to the tube diameter. Pipe ( 2 ) according to claim 5, wherein the tube diameter is a first tube diameter, the second cylindrical region ( 5 ) forms a second pipe diameter, and the second transition region ( 6 ) extends in the axial tube direction over a length which is at least equal to the second tube diameter. Pipe ( 2 ) according to one of claims 1 to 6, wherein the first cylindrical region ( 4 ) a first tube outer circumference and the flat tube region ( 3 ) forms a second tube outer circumference which is larger than the first tube outer circumference. Pipe ( 2 ) according to claim 7, wherein the second tube outer circumference exceeds the first tube outer circumference by more than 25%. Pipe ( 2 ) according to one of claims 1 to 8, wherein the flat tube region ( 3 ) forms a pipe main dimension between a first extreme point on one of the relatively short sides and a second extreme point on the other of the relatively short sides, and each of the curved paths (FIG. 13 ) is greater than the pipe main dimension. Pipe ( 2 ) according to one of claims 1 to 9, wherein at least one of the first and second cylindrical regions ( 4 . 5 ) a bulge ( 9 ). Pipe ( 2 ) according to one of claims 1 to 10, wherein the tube ( 2 ) comprises an aluminum alloy. Pipe ( 2 ) for a heat exchanger, comprising: - a pipe end; - a flat tube area ( 3 ) disposed away from the pipe end, the flat pipe region ( 3 ) two wide and flat, parallel spaced sides ( 12 ) connected by two relatively short sides; A cylindrical area extending from the pipe end to a first location ( 27 ), which is near the pipe end, extends; and - a transitional area ( 6 ), the cylindrical area and the flat tube area ( 3 ) and connects in the axial tube direction from the first position ( 27 ) to a second place ( 14 ), which is remote from the pipe end, wherein at least a portion of the flat pipe region ( 3 ) between the first place ( 27 ) and the second place ( 14 ) is located. Pipe ( 2 ) according to claim 12, wherein the transition region ( 6 ) to a peak in the second place ( 14 ) rejuvenated. Pipe ( 2 ) according to claim 12 or 13, wherein the intersection of the transition region ( 6 ) and one of the wide and flat sides ( 12 ) a curved way ( 13 ) form. Pipe ( 2 ) according to one of claims 12 to 14, wherein the cylindrical region forms a tube diameter and the distance in the axial tube direction between the first and second locations ( 27 . 14 ) is at least equal to the pipe diameter. Pipe ( 2 ) according to one of claims 12 to 15, wherein the cylindrical portion has a first tube outer circumference and the flat tube portion ( 3 ) forms a second tube outer circumference which is larger than the first tube outer circumference. Pipe ( 2 ) according to one of claims 12 to 16, wherein the second tube outer circumference exceeds the first tube outer circumference by more than 25%. Pipe ( 2 ) according to one of claims 12 to 17, wherein the pipe end a first tube ( 7 ), the cylindrical region is a first cylindrical region ( 4 ), and the transition area ( 6 ) is a first transition region, wherein the tube ( 2 ) further comprises: - a second tube ( 8th ) that opposite the first tube ( 7 ) is arranged; A second cylindrical area ( 5 ) extending from the second tube ( 8th ) to a third location close to the second pipe end ( 8th ) extends; and - a second transition region that covers the second cylindrical region ( 5 ) and the flat tube area ( 3 ) and connects in the axial tube direction from the third position to a fourth position, which from the second tube end ( 8th ), wherein at least a portion of the flat tube region (FIG. 3 ) is located between the third digit and the fourth digit. Pipe ( 2 ) according to one of claims 12 to 18, wherein the intersection points of each of the first and second transition regions ( 6 ) and each of the wide and flat sides ( 12 ) curved paths ( 13 ) form. Pipe ( 2 ) according to claim 19, wherein each of the curved paths ( 13 ) a tip, which at a median plane of the tube ( 2 ) is arranged.

Images