KR101562090B1 - Heat Exchanger Tube, heat exchanger Tube Assembly, and methods of making the same - Google Patents

Abstract

The tube assembly for use in a heat exchanger includes a flat portion having a wide, flat opposing tube side. The pin structure is joined to the wide, flat tube side of the flat part. The flat part of the tube is located between the cylindrical ends which can be inserted into the grommet. The structure of the tube assembly provides a rigid structure that is long enough to withstand the insertion and removal of a tube assembly to a heat exchanger, for example, a heavy duty radiator.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger tube, a heat exchanger tube assembly,

The present invention generally relates to tubes, fins and assemblies for heat exchangers, and methods of making the same.

A large heat exchanger is well known which utilizes an individually replaceable tube assembly having a tube for conveying the first fluid and a second heat transfer surface for the second fluid to transfer heat to the first fluid. As an example, this type of heat exchanger that functions as a heavy duty radiator for transferring waste heat from the engine coolant to air is described in Murray's patent document 1 and Neudeck's patent document 2. The tube assemblies used in these heat exchangers have a finned section for heat exchange and a cylindrical end without pins for insertion into a sealing grommet.

Heat exchanger tube assemblies of the type described above are typically constructed of copper, with the extended air side surface of the fin region soldered to the tube. Copper offers advantages of high thermal conductivity, ease of manufacture, and good strength and durability. However, steadily rising copper prices have led to demand for other inexpensive materials.

Aluminum replaced copper as a preferred constituent material in other heat exchangers (e.g., automobiles and commercial radiators), but failed to successfully replace copper in this type of heavy duty heat exchanger. Aluminum is much less durable than copper because of its low strength. This is particularly problematic for applications where the individual tube assembly needs to be removed and inserted in the field, since damage is likely to occur during such handling. Furthermore, bonding of aluminum components requires a significantly higher temperature than soldering of copper, making manufacture difficult. There is still room for improvement.

<Prior Art Literature>

Patent Document 1 US Patent No. 3,391,732

Patent Document 2 US Patent No. 4,236,577

The heat exchanger tube, the heat exchanger tube assembly and the method of manufacturing the same according to the present invention are intended to provide a heat exchanger tube, a heat exchanger tube assembly, and a manufacturing method thereof that are excellent in durability and easy to manufacture.

According to one embodiment of the present invention, a tube assembly for a heat exchanger includes a tube having a flat portion, wherein a wide tube side is spaced apart and joined by an opposed narrow tube side. The tube assembly also includes two fin structures, each having a ridge and valley of corrugations connected to each other by transverse sides and two planar side sheets. The corrugated trough portion of one fin structure is connected to one of the wide tube sides, and the corrugated ridge portion of the fin structure is connected to one of the side sheets.

In some embodiments, the tube includes a cylindrical portion at a longitudinal end of the tube, wherein a flat portion is disposed between the cylindrical portions. In some embodiments, the fin structure and side sheets are joined by brazing joints, and in some embodiments they are formed of one or more aluminum alloys. According to some embodiments, the thickness of the wide tube side is at least twice the thickness of the side sheet.

According to another aspect of the invention, a heat exchanger tube assembly includes a fluid flow tube that extends longitudinally over at least a portion of the tube assembly. Fluid flow tubes have a device number and a step dimension perpendicular to the longitudinal direction, the step dimensions being considerably smaller than the number of devices. The continuous tube wall surrounds the flow tube. The two planar side sheets are spaced equidistant from the combustion tube wall in the dimension dimension direction and are connected to the wall by a thin web.

In some such embodiments, the continuous tube wall defines a central moment of inertia of the tube wall with respect to the axis in the machine direction. In some embodiments, the central inertial moment of the tube assembly relative to its axis is at least five times the central inertial moment of the tubular wall, and in some embodiments at least ten times.

In some embodiments, the first circular tube portion is coupled to the continuous tube wall at the first end of the flow tube, and the second cylindrical portion is coupled to the continuous tube wall at the second end of the flow tube. In some such embodiments, the outer circumferential length defined by the continuous tube wall is greater than the at least one circumferential length of the cylindrical tube portion.

According to another aspect of the present invention, a method of making a heat exchanger tube assembly includes providing a tube, first and second pleated pin structures, and first and second planar side sheets. The first corrugated fin structure is disposed between the first side sheet and the first wide flat surface of the tube and the second corrugated fin structure is disposed between the second side sheet and the second wide flat surface of the tube. A compressive force is applied to the opposing face of the side sheet so that the ridgeline portion and the valley portion of the pin structure are brought into contact with the side sheet and the wide flat face and the contact between the first pin structure and the first side face sheet and between the first pin structure and the first wide flat face A brazing joint is formed between the second fin structure and the second side sheet, and between the second fin structure and the second broad flat surface.

In some such embodiments, the fin structure and the side sheet are raised in a vacuum environment to form a brazed joint. In other environments they are elevated in a controlled inert gas environment. In some embodiments, providing the tube, the pin structure and the side sheet includes providing a material coated with a brazing filler metal.

In some embodiments, the compressive force is transmitted through the first separating sheet adjacent the first side sheet and through the second separating sheet adjacent to the second side sheet. In some such embodiments, the separating sheet has a thermal expansion coefficient consistent with the tube, side sheet, and fin structure. In some embodiments, the first separation sheet is one of several separation sheets adjacent to the first side sheet.

According to another aspect of the present invention, a method of manufacturing a heat exchanger tube assembly includes providing a number of tubes, a number of wrinkle fin structures and a number of planar side sheets. Each tube is disposed between a plurality of pairs of wrinkle pin structures, wherein each wrinkle pin structure is disposed between one tube and one side sheet. The tube, the wrinkle pin structure and the side sheet are arranged in a laminate. Between the adjacent pair of side sheets, a separation sheet is disposed adjacent to the side sheet at the outermost end of the laminate. A compressive force is applied to the laminate in the lamination direction. A brazing joint is formed at the point of contact between the corrugated fin structure and the tube, and between the corrugated fin structure and the side sheet, and the brazed tube assembly is removed from the separator sheet.

In some such embodiments, the tube, the pin structure, and the side sheet are raised in a vacuum environment to form a brazed joint. In other environments they are elevated in a controlled inert gas environment. In some embodiments, providing the tube, the pin structure and the side sheet includes providing a material coated with a brazing filler metal.

According to another aspect of the invention, a heat exchanger tube includes 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 second cylindrical portion located between the ends, And includes a flat portion having two parallel spaced wide flat surfaces joined by a side surface. A transition region is located between each cylindrical portion and the flat portion. The intersection of each of the wide planar surfaces of the tube and the transition region defines a curved path.

In some such embodiments, the two short sides have an arcuate cross-sectional shape. In some embodiments, each of the curvilinear paths includes a vertex located at the center plane of the tube, and in some such embodiments, the arcuate path segment is located at some of these vertices.

In some embodiments, the transition region adjacent to one cylindrical portion extends over at least the same length as the diameter of the cylindrical portion. In some embodiments, the circumferential length of the flat portion of the tube is greater than the circumferential length of the at least one cylindrical portion, and in some embodiments is at least 25% greater.

In some embodiments, the flume defines a number of tubes between the two relatively short sides of the outermost point, each of the curved paths being longer than the number of tubes. In some embodiments, the tube is made of an aluminum alloy.

According to another embodiment of the present invention, the heat exchanger tube is formed by reducing the diameter of the first portion of the round tube and flattening the second portion adjacent to the first portion to define two spaced wide flat surfaces on the second portion To form a circular tube. In some embodiments, the first portion ends at an end of the tube. In some embodiments, the second portion becomes flat after reducing the diameter of the first portion.

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

In some embodiments, the mandrel is inserted into the tube before flattening the second portion, and is removed from the tube after the second portion is flattened.

In some embodiments, the diameter of the third portion of the round tube adjacent to the second portion is reduced. In some such embodiments, the third portion ends at the second end of the tube. In some embodiments, the second portion is flattened after reducing the diameter of the third portion.

The heat exchanger tube, the heat exchanger tube assembly, and the method of manufacturing the same according to the present invention include a flat portion between the cylindrical tubes, a transition region between the flat portion and the cylindrical tube, and a heat exchanger A tube, a heat exchanger tube assembly, and a manufacturing method thereof.

1 is a perspective view of a heat exchanger tube assembly in accordance with an embodiment of the present invention.
Figure 2 is an elevation view of the heat exchanger tube assembly of Figure 1;
Figure 3 is a detail view of the portion of Figure 2 shown in line III-III.
Figure 4 is a top view of the heat exchanger tube assembly of Figure 1;
Figure 5 is an exploded perspective view of the heat exchanger tube assembly of Figure 1;
Figure 6 is an elevational view of a stack of heat exchanger tube assemblies made in accordance with one embodiment of the present invention.
Figure 7 is a plan view of certain components of the stack of Figure 6;
8 is a perspective view of a heat exchanger tube according to an embodiment of the present invention.
Figure 9 is a partial perspective view of a prior art heat exchanger tube.
10 is a partial cross-sectional view along line XX of Fig. 8; Fig.
11 is a cross-sectional view taken along the line XI-XI in Fig. 8;
Figure 12 is a partial perspective view of the partially formed tube of Figure 8;
Figs. 13A and 13B are schematic views of a molding operation for manufacturing the tube of Fig. 8; Fig.

Before describing in detail certain embodiments of the invention, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description and illustrated in the following drawings . The invention is capable of other embodiments and of being practiced or of being carried out in various ways. It is also to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. &Quot; including ", " comprising ", or " having "and variations thereof mean inclusion of the items listed thereafter and equivalents thereof and the appended claims. The terms "attached," " coupled, "" supported," and "coupled," and variations thereof, unless otherwise specified or limited, include both direct and indirect mounting, . Also, "coupled" and "coupled" are not limited to physical or mechanical connections or couplings.

A laminate assembly 1 according to an embodiment of the present invention is shown in Figs. Such a tube assembly 1 can be used as one of many large-scale heavy-duty heat exchangers such as excavators, mining trucks, power generation plants, for example, many individual tubes of a radiator. It should be understood, however, that this tube assembly 1 can be used in heat exchangers of various types and sizes.

The tube assembly 1 includes a tube 2 extending from the first end 7 to the second end 8. The tube (2) defines a fluid flow tube so that fluid (e.g., engine coolant) can be conveyed through the tube assembly (1). As an example, the tube assembly 1 may be used in an engine coolant radiator to discharge waste heat from the flow rate of the engine coolant fluid as the engine coolant flow rate flows from one end of the ends 7, 8 to the other end.

The tube (2) comprises a flat part (3) located between the ends (7, 8). The flat portion 3 (best described with reference to FIG. 11) includes parallel first flat surfaces 12 and second flat surfaces 12. The wide flat surfaces 12 are spaced apart from each other and are connected by two opposed narrow side surfaces 15 which are spaced apart from each other. The sagittal side surface 15 is shown in an exemplary embodiment as an arcuate cross-sectional shape, but in other embodiments, the sagittal side surface 15 may be straight or some other cross-sectional shape. The two wide flat surfaces 12 and the two narrow sides 15 together define a continuous tubular wall 25 of the fluid flow conduit and define a continuous tubular wall 25 for allowing the flow rate of the fluid to pass through the tubular 2. [ An open space is formed inside. Although nothing is shown in the exemplary embodiment, it may be desirable in some instances to provide a surface enhancement or turbulence feature in the flow tube to enhance the heat transfer rate between the fluid passing through the tube 2 and the tube wall 25 have.

11, the flat portion 3 of the tube 2 has a dimension d1 of the tube defined as the distance between the outward faces of the two wide flat faces 12, 15 as the distance between the outermost points of the tubes. In some highly preferred embodiments, the number of devices d2 is several times greater than the dimension d1. By way of example, the number of devices in the exemplary embodiment is nine times greater than the end dimension.

The tube assembly 1 further comprises two convoluted fin structures 10 disposed along the flat portion 3. The tube assembly 1 is shown in Fig. The fin structure 10 includes a plurality of transverse sides 16 alternately connected by ridge 18 and valley 17 so that each fin structure 10 has a substantially sinusoidal shape city). The fin structure 10 may be a simple type, as shown in Figure 3, or it may include additional features to enhance heat transfer, structural strength, durability, or a combination thereof. For example, in some embodiments, the fin structure 10 includes a louver, bump, slit, lance, or other feature known to improve the heat transfer and / or structural stiffness of the transverse side 16 . In other embodiments, an edge boundary may be provided at one or both ends of the fin structure 10 adjacent the sidewall side 15. Such edge boundaries may be particularly advantageous in providing resistance to damage which may be caused by collision of stones or other debris.

The tubular assembly 1 also includes a thin side sheet 11. These side sheets 11 are parallel to the opposing wide flat face 12 of the tube 2 and are spaced at the same distance from either side by the fin structure 10. The lateral sides 16, ridges 18 and valleys 17 of the fin structure 11 thus provide a plurality of thin webs to separate the side sheets 11 from the continuous wall 25. The side sheets 11 are generally planar, but may include features such as, for example, curved edges, for increased rigidity and / or ease of assembly.

The space between the transverse sides 16 provides a flow channel for the fluid to be in heat transfer relationship with the fluid passing through the tube 2 and thus can be heat exchanged between the two fluids. By way of example, ambient air may be directed through the flow channel to cool the engine jacket coolant passing through the tube (2). However, it should be understood that various other fluids may be given in the heat transfer relationship using the tube assembly 1. Each of the flow channels between the transverse sides 16 is further defined by one of the valley 17 and the ridge 18 and by one of the flat surface 12 and the flat side sheet 11 of the tube 2. [ do. By thus fully defining the boundaries of the flow channels, the fluid passing through these channels is prevented from prematurely exiting the channels, thus enhancing the heat transfer capability.

The tube 2, the pin structure 10 and the side sheet 11 are preferably joined together to form a single structure in order to provide good thermal contact between fluids to be heat-transferred and good structural integrity. In a highly preferred embodiment, the tube 2, the pin structure 10 and the side sheet 11 are formed of a metal having high thermal conductivity, such as aluminum, copper, etc., although various materials can be used to construct the tube assembly. These components can be joined together in various processes, including brazing, soldering, gluing, etc., to form the tube assembly 1.

It may be advantageous for the fin structure 10 and the side sheet 11 to extend over the total number of devices d2 of the flat part 3 in order to promote good heat transfer between fluids. In some cases it may be desirable to extend the fin structure 10 and the side sheet 11 slightly beyond the outer edge of the sidewall side 15 to protect the fluid flow tube from damage due to collision of stones or other debris have.

It has been found that the tube assembly 1 is largely stiffened against bending around the central axis in the apparatus number d2 of the tube when the extremely thin side sheet 11 is interposed. The continuous tubular wall 25 provides only a durability against bending around its central axis in the absence of the side sheet 11 since the pin structure 10 provides very small stiffness in this direction due to its wraparound nature. Because of the relatively small stepped dimension d1 of the flat part 3, the resistance to bending around the center axis by only the continuous pipe wall 25 is very small, and the spacing of the side sheets 11 from the center axis It is quite advantageous if the distance is considerably larger than the dimension d1.

The influence of the side sheet 11 on the bending stiffness of the tube assembly 1 about the central axis in the number d2 of the tubes is determined by the fact that the center inertia moment about the axis of the tube assembly 1, (The pin structure 10 does not contribute to the central moment of inertia other than to maintain the deviation of the side sheet 11 from the flat surface 12 of the tube 2) . For the exemplary embodiment where the wall thickness is 0.8 mm, the sidewall thickness is 0.25 mm, the height of the fin structure is 6.55 mm, the dimension is 3.7 mm and the number of devices is 23.27 mm, the number of tubes in the tube assembly and tube The center of gravity moments for the axis are 925 mm ⁴ and 76 mm ⁴ . In other words, the center inertial moment of the tube assembly about the tube axis of the tube is approximately 12 times the inertial moment of the tube itself. In a preferred embodiment, the central inertial moment of the tube assembly about the device water axis of the tube is at least five times the inertia moment of the tube itself, and at least ten times in the highly preferred embodiment. This is particularly preferable when the tube 2 is composed of a material exhibiting a relatively low modulus of elasticity, for example, an aluminum alloy.

The tube 2 of the exemplary embodiment further includes a first cylindrical portion 4 adjacent the first end 7 and a second cylindrical portion 5 adjacent the second end 8, Is disposed between the first and second cylindrical portions. These cylindrical portions 4 and 5 allow the tube assembly 1 to be inserted securely and without leakage into the receiving grommet disposed in the opposite header (not shown) of the heat exchanger. The length of the cylindrical end is preferably kept to a minimum and the length of the flat part 3 is preferably at least 90% of the total length of the tube 2, in order to maximize the amount of tubes available for effective heat transfer. A circumferential bead 9 is provided in the cylindrical portion 5 of the exemplary embodiment to limit downward movement of the tube assembly 1 when vertically disposed in the heat exchanger.

It should be understood that the embodiment shown in the accompanying drawings includes a cylindrical end at both ends of the tube, but in some cases the tube assembly 1 may be without either or both of the two side end portions 4, When such a cylindrical end is not included, the corresponding receiving grommet may be provided with a receiving opening corresponding to the cross-sectional shape of the continuous wall 25 of the flat part 3.

In a specific preferred embodiment of the present invention, by forming a brazed joint between the aluminum tube 2, the first and second aluminum wrinkle pin structures 10, and the first and second aluminum side sheets 11, A tube assembly (1) is made. The first corrugated fin structure 10 is disposed between the first side sheet 11 and the wide first flat surface 12 of the tube 2 while the second corrugated fin structure 10 is disposed between the first side sheet 11 11 and the second wide flat surface 12 of the tube 2. [ The ridge portion 18 and the valley portion 17 of the fin structure 10 are brought into contact with the adjacent portion so that the assembly is compressed so that the brazing joint can be formed at the contact point.

Brazing filler metal having a melting point lower than the melting point of the tube (2), the fin structure (10) and the side sheet (11) is used to form the brazing joint. Such filler metals are typically aluminum with small amounts of other elements added (e.g., silicon, copper, magnesium, and zinc) to lower the melting point. The brazing filler metal may advantageously be provided as a coating on one or more components of the component to be brazed. In some embodiments, since both sides of the sheet material used to form the corrugated fin structure 10 are coated with the brazing filler metal, the brazing joint provides the desired brazing filler metal at all of the points of contact that are needed, And does not have a brazing filler metal in an undesirable position.

Although many methods can be used to increase the temperature of the tube 2, the pin structure 10, and the side sheet 11 to melt the brazing filler metal to form the brazing joint, two particularly preferred methods are vacuum brazing And atmosphere controlled brazing. In vacuum brazing, the assembled parts are placed in a sealed furnace and virtually all air is removed to create a vacuum environment. In this process, as the components are heated, the magnesium present in the alloy is released and acts to destroy the oxide layer present on the outer surface of the component, so that the molten brazing filler metal is bonded to the exposed aluminum. The oxide layer is not re-formed because it is oxygen free in a vacuum environment and does not interfere with metal bonding.

In atmosphere controlled brazing, flux is applied to the component before heating. Heating of the component is performed in an inert gas environment to prevent reformation of the oxide layer after the flux reacts with the oxide layer present on the relative surface of the component. When the oxide layer is replaced, the molten brazing filler metal is bonded to the exposed aluminum to form a brazed joint.

It may be particularly desirable to braze several tube assemblies 1 one at a time in order to increase the throughput in the production production environment. Figure 6 shows a method according to an embodiment of the present invention in which four tube assemblies 1 are made at the same time. It should be understood that this method can be used to produce more or less than four tube assemblies at a time.

In the embodiment of Fig. 6, the tube 2, the corrugated fin structure 10 and the general flat side sheet 11 are provided. Each tube 2 is disposed between a plurality of pairs of wrinkle pin structures 10 and each wrinkle pin structure 10 is disposed between one tube 2 and one planar side sheet 11. The separating sheet 19 is disposed between the adjacent pair of the planar side sheets 11. The tube 2, the corrugated fin structure 10, and the planar side sheet 11 are disposed in the laminate body 26. The additional separating sheet 19 is disposed adjacent the planar side sheet 11 at the outermost end of the laminate body 26 and the ridge portion 18 and the valley portion 17 of the wraparound fin structure, A compressive load is applied to the laminate 26 in the stacking direction so as to make contact with the wide flat face 12 of the pipe 11 and the pipe 2.

A bar 21 (for example, a structural steel channel) having high rigidity at the outermost end of the laminate 26 may be used to provide a uniform compressive load to the laminate 26. [ The compressive load can be maintained after a compressive load is applied to the laminate by using the metal band 22 surrounding the laminate 26 at several positions. The tension in the band 22 maintains the compressive load since the band 22 is tightened onto the bar 21 in a state in which the laminate is compressed. After being assembled in this manner, the laminate 26 is put into a brazing furnace to form individual tube assemblies 1. The laminate 26 is heated in a furnace to a temperature suitable for melting the brazing filler metal and then the laminate 26 is cooled to resolidify the melted braze filler metal so that a brazing joint is formed at the point of contact do. After cooling, the individual tube assemblies 1 brazed to the individual monolithic structures can be removed from the separating sheet 19. The separating sheet 19 may be provided with a coating to completely prevent the metal bonding between the separating sheet 19 and the side sheet 11 or this undesirable bonding may occur at the brazing temperature without the brazing filler metal It is because.

Since the laminate 26 is heated to the brazing temperature, expansion of the metal material in the laminate 26 will occur. In aluminum brazing, the components are typically heated to a brazing temperature of 550 [deg.] To 650 [deg.] C. This temperature range is considerably higher than the temperature used to solder the copper component and therefore the thermal expansion experienced by the components of the tube assembly 1 during this bonding process is considerably greater when the component is aluminum than when it is copper.

The inventors have found that the pin structure 10 must be heated during the brazing process to prevent it from being deformed by being cooled to ambient temperature after being heated to the brazing temperature. Unlike in the traditional brazed aluminum radiator manufacture which involves joining multiple rows of tubes and pin structures together to form a single brazed core, the transverse sides 16 of the fin structure 10 are joined to the components of the tube assembly 1 And the separating sheet 19 due to the thermal expansion difference. In some embodiments of the invention, this problem is improved by matching the coefficient of thermal expansion of the separating sheet 19, which generally coincides with the tube 2, the pin structure 10 and the side sheet 11. This can be done by forming a similar aluminum alloy, or other material exhibiting a similar thermal expansion coefficient, to the separating sheet 19. [

Alternatively, or in addition, a plurality of individual separation sheets 19 may be used between each adjacent tube assembly 1, as shown in Fig. A gap 20 is provided between adjacent separation sheets in the individual separation sheet 19. When the separating sheet 19 is made of a material having a thermal expansion coefficient that is significantly different from the constituent materials of the tube 2, the pin structure 10 and the side sheet 11, (20) can be increased or decreased, so that the deformation of the pin structure, which may be caused by inconsistency of the thermal expansion coefficient, is considerably mitigated. The gap 20 acts as a barrier to avoid the accumulation of deformation caused by thermal expansion, so that such deformation is confined to the individual contact zones beneath each individual separation sheet 19. The assembly method shown in Fig. 7 is particularly advantageous when a material having higher heat resistance such as stainless steel is used for the separating sheet 19 and the constituent elements of the tube assembly 1 are made of aluminum.

The tube 2 will now be described in detail with particular reference to Figures 8-13. As described above, the embodiment (2) of the tube shown in Fig. 8 includes the flat portion 3 located between the first cylindrical portion 4 and the second cylindrical portion 5. The first cylindrical tube portion 4 extends from the first end 7 of the tube 2 while the second cylindrical tube portion 5 extends from the second end 8 of the tube 2. A transition region (6) is located between the flat portion (3) and each of the cylindrical portions (4, 5). The transition region 6 can avoid mechanical stress concentration locations of the tubing material in addition to providing a smooth, continuous flow path for the fluid passing through the tube 2. [

The transition region 6 has a length L extending from a position 27 close to the end 7 of the tube 2 to a position 14 far from the end 7 as shown in a partial cross- . The length L is preferably at least equal to the diameter of the cylindrical end 4, but in some other embodiments may be smaller in size than the diameter of the corresponding end. As can be seen in figure 8, the wider flat surface 12 is formed by a portion of the wider flat surface 12, which is located between the tubes 2, between the positions 27 and 14 defining the beginning and end of the transition region 5. [ Lt; RTI ID = 0.0 &gt; 14 &lt; / RTI &gt;

In a preferred embodiment, the intersection of the transition region 6 and the wide flat face 12 of the flat zone 3 defines a curved path 13. These curved paths 13 provide favorable rigidity of the flat part 3 of the tube 2 with respect to the bending moment about the device water axis of the tube. For comparison, a prior art tube 102 is shown in FIG. 9, which includes a first flat portion 103 coupled to a cylindrical portion 104 by a transition portion 106. The intersection point of the transition region 106 and the flat portion 103 defines a straight path 113 on the wide flat surface 112 of the flat portion 103.

The straight path 113 extends from the tube number of the tube and is very easy to deflect about the device water axis. This can be particularly disadvantageous during installation and / or removal of tube assemblies containing tube 102, such as during installation, in a heat exchanger, since such installation and removal frequently adds this type of bending moment to the tube. This problem is particularly exacerbated when the tube is composed of a very low strength material such as annealed aluminum.

The present inventors have found that the curved path 13 provides a considerable rigidity effect that can withstand the bending moments of the type described above and provides for the installation, removal and other handling of the tube assembly 1 containing the tube 2 or tube 2 To prevent buckling or other damage of the tube (2). It may be particularly advantageous that path 13 is defined by a series of connected arcuate path segments, although any non-linear pathway may benefit.

In this exemplary embodiment, the curvilinear path 13 includes a vertex, which is located approximately at the center plane of the tube, so that the vertex is at an end 7 (the transition region is defined by the flat portion 3 and the first cylindrical end 4 ) Or at the point 14 on the path 13 farthest from the end 8 (where the transition region is between the flat portion 3 and the second cylindrical end 5). The path 13 preferably includes an arcuate path segment at the apex to avoid stress concentration at this apex.

In some preferred embodiments, the outer periphery (i.e., the circumference) of at least one of the two cylindrical portions 4, 5 is smaller than the outer periphery of the continuous pipe wall 25 in the flat portion 3. Advantageously, therefore, a heat transfer surface of a relatively large length is possible in the flat part 3 without the need of correspondingly large diameters on one or both of the ends 7, 8. Small diameters may be preferred at the ends, since they may make the spacing of adjacent tube assemblies closer and require smaller sealing surfaces at the ends, for example. In some preferred embodiments, the outer periphery of the flat portion 3 exceeds at least 25% of the outer periphery of at least one of the two cylindrical ends.

BACKGROUND OF THE INVENTION Heat exchangers comprising a fluid delivery tube having a flat cross-sectional shape over an entire length of space are well known in the art and have been used for decades as radiators and the like. This type of plausibility usually consists of one of two methods. These tubes may be extruded and / or drawn out into a flat shape from the billet material and then cut into individual lengths, or the shape of the coil sheet may be formed into a round shape and then seam welded, then planarized into a flat tube shape by a roller, Shaped sheet is rolled to form a tube.

In the case of a tube such as the prior art tube 102 (FIG. 9) having a flat portion 103 and a cylindrical end 104, the end of the tubular tube is formed in a cylindrical shape to define a cylindrical end 104 and a transition portion 106 Respectively. This operation can be carried out quickly and easily when the tube is composed of a high malleable material such as copper and only the extreme end of the tube 2 is molded. However, this method can not obtain the transition portion 6 as described above.

The transition region 6 can be formed by first molding a round tube 2 having an outer diameter equal to the desired outer circumferential length of the continuous tube wall 25 of the flat part 3. [ 12, the diameter of the end of the round tube 2 is reduced so that in addition to the cylindrical ends 4 and 5, the central portion 3 'and the end portions 4, 5 of the tapered transition region 6 '. This reduction in diameter can be achieved, for example, by swaging the end of the tube. In some preferred embodiments, the diameter of the ends is reduced by at least 20% to obtain a desired ratio of circumferential length between the flat portion 3 and the cylindrical ends 4, 5.

13A and 13B, the cross-sectional shape of the flat portion 3 of the tube 2 is formed in the tube 2 between the first molding die half 22 and the second molding die half 23, By shaping the corresponding portion 3 'of the substrate 3'. The tube 2 is inserted between the die halves 22, 23 when the die is in the open position, i.e. when the die halves are separated from each other as in Fig. 13a. When the tube 2 is thus positioned, the die is closed to the closed position of FIG. 13B, so that the flat portion 3 of the tube 2 is formed with the step size d1 and the device number d2. Optionally, the mandrel 24 may be placed in the tube 2 prior to the molding operation to prevent buckling or other undesirable deformation of the wide flat wall 12 during the molding operation. When the mandrel 24 is used, the mandrel can be removed from the tube 2 after the molding operation is completed. Since the shape of the transition region 6 can be created by including complementary intaglio shapes of the shape on the contact surfaces of the die halves 22 and 23, As shown in FIG.

Various features of certain features and elements of the invention are set forth with reference to specific embodiments thereof. It is to be understood that any alternative features, elements, and workarounds described with reference to a particular embodiment may be applied to other embodiments, with the exception of features, elements, and work styles that are mutually exclusive or incompatible with each of the above- You should know.

It is to be understood that the embodiments described above and illustrated in the drawings are illustrative only and are not intended to limit the concepts and principles of the invention. It will be appreciated by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

1: tube assembly 2: tube
3: flat part 4: first cylinder part - first cylindrical tube part
5: second cylindrical tube portion 6: transition region
7: end portion 8: end portion
9: circumferential bead 10: pin structure
11: side sheet - first side sheet 12: flat surface
13: Curved path 14: Position / point
15: side to side 16:
17: valley 18: ridge line
19: separating sheet 20: gap
21: bar 22: metal band
23: first molding die half part 23: second molding die half part
24: mandrel 25: continuous pipe wall
26: laminate 27: position
102: tube 103: first flat part
104: Cylindrical end 106:
112: flat surface 113: straight path
3 ': center portion 6': tapered transition region
d1: Short dimension d2: Number of units

Claims (23)

delete delete delete delete delete delete A tube assembly for a heat exchanger,
A fluid flow conduit extending longitudinally over at least a portion of the tube assembly and having a smaller number of devices in a first direction perpendicular to the longitudinal direction and in a second direction perpendicular to the longitudinal direction,
A continuous tubular wall extending around the fluid flowtube,
First and second planar side sheets spaced at equal distances from the continuous pipe wall in the second direction on both sides of the continuous pipe wall,
And a plurality of thin webs connecting the first and second planar side sheets to the continuous tubular wall,
Wherein the continuous tubular wall defines a central moment of inertia of the tubular wall with respect to an axis extending in the first direction and wherein a central moment of inertia of the tubular assembly with respect to the axis is at least five times the central moment of inertia of the tubular wall. delete 8. The method of claim 7,
Wherein the central moment of inertia of the tube assembly with respect to an axis extending in the first direction is at least ten times the central moment of inertia of the tube wall. 8. The method of claim 7,
Wherein the central inertial moment of the tube assembly with respect to the axis extending in the first direction is twelve times the central inertial moment of the tube wall. 8. The method of claim 7,
A first tubular portion coupled to the continuous tubular wall at a first end of the fluid flowtube,
And a second circular tube portion coupled to the continuous tube wall at a second end of the fluid flow tube,
Wherein the first and second cylindrical tubes each define an inlet and an outlet of the fluid flow tube. A tube assembly for a heat exchanger,
A fluid flow conduit extending longitudinally over at least a portion of the tube assembly and having a smaller number of devices in a first direction perpendicular to the longitudinal direction and in a second direction perpendicular to the longitudinal direction,
A continuous tubular wall extending around the fluid flowtube,
First and second planar side sheets spaced at equal distances from the continuous pipe wall in the second direction on both sides of the continuous pipe wall,
A plurality of thin webs connecting said first and second planar side sheets to said continuous wall,
A first tubular portion coupled to the continuous tubular wall at a first end of the fluid flowtube,
And a second circular tube portion coupled to the continuous tube wall at a second end of the fluid flow tube,
The first and second cylindrical tubes each defining an inlet and an outlet of the fluid flow tube,
Wherein the first tubular portion defines an outer circumferential length of the second tube and the second tubular portion defines an outer circumferential length of the third tube, And wherein the at least one of the second and third tube circumferential lengths is greater than at least one of the second and third tube circumferential lengths. 8. The method of claim 7,
The continuous tubing wall, the first and second planar side sheets, and the plurality of thin webs being joined by brazing joints. 8. The method of claim 7,
The continuous tubular wall, the first and second planar side sheets, and the plurality of thin webs are formed of one or more aluminum alloys. 8. The method of claim 7,
Wherein the plurality of webs and the first and second planar side sheets extend across the number of devices in the fluid flow conduit. 8. The method of claim 7,
The continuous tubular wall having a first material thickness and the first and second planar side sheets having a second material thickness wherein the first material thickness is at least twice the second material thickness. 8. The method of claim 7,
Wherein at least one of the first and second planar side sheets has a first side sheet end and a second side sheet end,
Wherein a first distance in the longitudinal direction between one of the first side sheet end and the second side sheet end and the adjacent tube assembly end is greater than a first distance between the other of the first planar side sheet end and the second planar side sheet end, And a second distance in the length direction between the tube assembly end and the opposite tube assembly end. 8. The method of claim 7,
Wherein at least one end of the fluid flow conduit is defined by the device number at least partially greater than the end dimension,
Wherein the at least one end extends longitudinally across at least one adjacent end of the planar side sheet. 8. The method of claim 7,
Wherein the first end and the second end of the fluid flow conduit are defined by the device number at least partially greater than the end dimension,
Wherein the first end of the fluid flow conduit extends longitudinally over an adjacent first end of at least one of the planar side sheets,
Wherein the second end of the fluid flow conduit extends in a longitudinal direction opposite the first end of the fluid flow conduit and has a second end at least one of the planar side sheets opposing the first end of at least one of the side sheets Tube assemblies for heat exchangers. 8. The method of claim 7,
Wherein at least one of the first and second planar side sheets is shorter in length than the fluid flow tube in the longitudinal direction. 8. The method of claim 7,
Wherein at least one of the plurality of thin webs extends at an equal distance in the longitudinal direction at least one of the first and second planar side sheets. 13. The method of claim 12,
Wherein at least one of the first and second planar side sheets is shorter in length than the fluid flow tube in the longitudinal direction. 13. The method of claim 12,
Wherein at least one of the plurality of thin webs extends at an equal distance in the longitudinal direction at least one of the first and second planar side sheets.

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