JP2017506320A - Heat exchanger tube assembly and method of manufacturing heat exchanger tube assembly - Google Patents

Abstract

A tube assembly for use in a heat exchanger includes a flat portion having opposing wide flat tube sides. A fin structure is joined to the side of the wide flat tube at the flat part. Side sheets are joined to opposite ends of the fin structure. The flat portion of the tube is located between the cylindrical ends configured to be inserted into the grommet. The configuration of the tube assembly provides a strong structure for intactly inserting and removing the tube assembly from the heat exchanger (eg, a radiator for heavy machinery). [Selection] Figure 15

Description

  [0001] This application claims priority to US patent application Ser. No. 14 / 175,004, filed Feb. 7, 2014, the entire contents of which are hereby incorporated by reference.

  [0002] The present invention relates generally to tubes, to fins and tube assemblies for heat exchangers, and to methods for their manufacture.

  [0003] Individually exchangeable discretes having a tube for transferring a first fluid and a second heat transfer surface region for a second fluid that transfers heat to and from the first fluid Large scale heat exchangers incorporating typical tube assemblies are well known. As an example, this type of heat exchanger functioning as a radiator for heavy machinery for transferring waste heat from engine coolant to air was granted to US Pat. No. 3,391,732 issued to Murray or to Neudeck. U.S. Pat. No. 4,236,577. The tube assemblies used in these heat exchangers have a finned center for heat exchange and a cylindrical end without fins for insertion into a seal grommet.

  [0004] A heat exchanger tube assembly of the type described above is typically constructed from copper, with the expanded air side surface of the finned region soldered to the tube. Copper offers the advantages of high thermal conductivity, easy manufacturability, good strength and durability. However, the steadily increasing number of copper pieces has led to the need for alternative lower cost materials.

  [0005] Aluminum has been replaced by copper as a preferred material in other heat exchangers (eg automotive radiators and commercial radiators), but in this type of heavy equipment heat exchanger, it has been successfully replaced by copper. It is not done. Aluminum is substantially less strong than copper, leading to durability concerns. This is particularly problematic in applications where individual tube assemblies are removed and fitted in the field. This is because damage is likely to occur during such handling. Moreover, joining aluminum parts requires substantially higher temperatures than copper soldering, which leads to manufacturing difficulties. Therefore, there is still room for improvement.

  [0006] According to one embodiment of the present invention, a tube assembly for a heat exchanger includes a tube having a flat portion having spaced apart wide tube sides. The wide tube side surfaces are joined by the opposing narrow tube side surfaces. The tube assembly further comprises two fin structures. Each of the fin structures has a corrugated top and corrugated valley connected by side portions, and two substantially planar side sheets. The corrugated trough of one fin structure is joined to one of the wide tube sides. The corrugated top of this fin structure is joined to the surface of one of the side sheets. The corrugated troughs of other fin structures are joined to other wide tube side surfaces. The corrugated top of the fin structure is joined to the surface of another side sheet.

  [0007] In some embodiments, the tube comprises a cylindrical portion at the longitudinal end of the tube. A flat portion is disposed between the cylindrical portions. In some embodiments, the tube, fin structure and sidesheet are joined by a brazed joint. In some embodiments, these are formed from one or more aluminum alloys. According to some embodiments, the width of the wide tube side is at least twice the thickness of the sidesheet.

  [0008] According to another embodiment of the present invention, a tube assembly for a heat exchanger includes 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 of which are perpendicular to the longitudinal direction. The minor dimension is substantially smaller than the major dimension. A continuous tube wall surrounds the distribution conduit. The two substantially flat side sheets are spaced from the continuous tube wall at equal intervals in the sub-dimension direction, and are connected to the tube wall by a thin web.

  [0009] In some such embodiments, the continuous tube wall forms a tube wall centroid moment of inertia relative to the major dimensional axis. In some embodiments, the inertia of the tube assembly inertia about this axis is at least five times the tube wall centroid moment of inertia, and in some embodiments, at least ten times.

  [0010] In some embodiments, the first cylindrical tube portion is joined to the continuous tube wall at the first end of the flow conduit and the second cylindrical tube portion is the second of the flow conduit. To the continuous tube wall at the end. In some embodiments, the outer periphery formed by the continuous tube wall is larger than the outer periphery of at least one of the cylindrical tube portions.

  [0011] According to another embodiment of the present invention, a method of manufacturing a heat exchanger tube assembly includes a tube, first and second corrugated fin structures, and first and second substantially planar sidesheets. Are provided. The first corrugated fin structure is disposed between the first sidesheet and the first wide flat side of the tube. The second corrugated fin structure is disposed between the second side sheet and the second wide flat side surface of the tube. A compressive force is applied to both sides of the side sheet, and the top and valleys of the fin structure are arranged to contact the side sheet and the wide flat side surface. The brazed joint is between the first fin structure and the first side sheet, between the first fin structure and the first wide flat side surface, and between the second fin structure and the second side sheet. In the meantime, it is formed between the second fin structure and the second wide flat side surface.

  [0012] In some such embodiments, the temperature of the tube, fin structure and sidesheet is increased in a vacuum environment to form a brazed joint. In other environments, these temperatures are increased in a controlled inert gas environment. In some embodiments, providing the tube, fin structure and side sheet comprises providing a material coated with a brazing material.

  [0013] In some embodiments, the compressive force is transmitted through the first separator sheet adjacent to the first side sheet and through the second separator sheet adjacent to the second side sheet. In some such embodiments, these separator sheets have a coefficient of thermal expansion that approximately matches the coefficient of thermal expansion of the tube, side sheet, and fin structure. In some embodiments, the first separator sheet is one of several separator sheets adjacent to the first side sheet.

  [0014] According to another embodiment of the present invention, a method of manufacturing a heat exchanger tube assembly includes a number of tubes, a number of corrugated fin structures, and a number of substantially planar side seats. The process to do is provided. Each of the tubes is disposed between a pair of corrugated fin structures. Each of the corrugated fin structures is disposed between one of the tubes and one of the side seats. The tube, the corrugated fin structure and the side sheet are arranged into a laminate. A separator sheet is disposed adjacent to the side sheet between the pair of adjacent side sheets at the outermost end of the laminate. A compressive load is applied to the stack in the stacking direction. A brazed joint is formed at the point of contact between the corrugated fin structure and the tube and the point of contact between the corrugated fin structure and the sidesheet, and the brazed tube assembly is removed from the separator sheet.

  [0015] In some such embodiments, the temperature of the tube, fin structure and sidesheet is increased in a vacuum environment to form a brazed joint. In other environments, these temperatures are increased in a controlled inert gas environment. In some embodiments, providing the tube, fin structure and side sheet comprises providing a material coated with a brazing material.

  [0016] According to another embodiment of the present invention, a tube for a heat exchanger extends from a first cylindrical portion that extends from a first end of the tube and from a second end of the tube. A second cylindrical portion, and a flat portion disposed between the first end portion and the second end portion. The flat has two spaced parallel wide flat sides joined by two relatively short sides. A transition region is disposed between each of the cylindrical portions and the flat portion. A curved path is formed by the intersection of each of the wide flat sides of the tube with the transition region.

  [0017] In some such embodiments, the two relatively short sides have an arcuate shape. In some embodiments, each of the curved paths has a vertex located at the central plane of the tube, and in some such embodiments, an arcuate path segment is located at the vertex. Is done.

  [0018] In some embodiments, the transition region adjacent to one of the cylindrical portions extends for a length at least equal to the diameter of this portion. In some embodiments, the outer periphery of the flat portion of the tube is larger than the outer periphery of at least one of the cylindrical portions, and in some embodiments, at least 25 percent greater.

  [0019] In some embodiments, the flat tube portion forms a tube major dimension between the outermost points of two relatively short sides, and each of the curved paths is longer than the tube major dimension. In some embodiments, the tube is formed from an aluminum alloy.

  [0020] According to another embodiment of the invention, the heat exchanger tube reduces the diameter of the round tube in the first portion of the round tube and flattens the second portion adjacent to the first portion. And formed from a round tube by forming two spaced apart wide flat sides in the second portion. In some embodiments, the first portion terminates at one end of the tube. In some embodiments, the second portion is planarized after the diameter of the first portion is reduced.

  [0021] In some embodiments, the diameter of the first portion is reduced by a stretching process. In some embodiments, the second portion is flattened by striking that portion in an embossing plate. In some embodiments, the tube is formed from an aluminum alloy.

  [0022] In some embodiments, the mandrel is inserted into the tube prior to planarizing the second portion and removed from the tube after planarizing the second portion.

  [0023] In some embodiments, the diameter of the third portion of the round tube is reduced. This third part is adjacent to the second part. In some such embodiments, the third portion terminates at the second end of the tube. In some embodiments, the second portion is planarized after reducing the diameter of the third portion.

[0024] FIG. 6 is a perspective view of a heat exchanger tube assembly according to an embodiment of the present invention. [0025] FIG. 2 is an elevational view of the heat exchanger tube assembly of FIG. [0026] FIG. 3 is a detailed view of a portion of FIG. 2 bounded by line III-III. [0027] FIG. 2 is a plan view of the heat exchanger tube assembly of FIG. [0028] FIG. 2 is an exploded perspective view of the heat exchanger tube assembly of FIG. [0029] FIG. 4 is an elevational view of a stack of heat exchanger tube assemblies manufactured in accordance with one embodiment of the present invention. [0030] FIG. 7 is a plan view of several components of the stack of FIG. [0031] FIG. 3 is a perspective view of a heat exchanger tube according to an embodiment of the invention. [0032] FIG. 6 is a partial perspective view of a prior art heat exchanger tube. [0033] FIG. 9 is a partial cross-sectional view taken along line XX of FIG. [0034] FIG. 9 is a cross-sectional view taken along line XI-XI in FIG. [0035] FIG. 9 is a partial perspective view of the partially formed tube of FIG. [0036] FIG. 9 is a schematic view of a forming process for manufacturing the tube of FIG. It is the schematic of the shaping | molding process for manufacturing the tube of FIG. [0037] FIG. 6 is a perspective view of a heat exchanger tube assembly according to another embodiment of the present invention. [0038] FIG. 15 is an exploded perspective view of the heat exchanger tube assembly of FIG. [0039] FIG. 15 is a partial cross-sectional view taken along line XVI-XVI of FIG.

  [0040] Prior to describing embodiments of the present invention in detail, the present invention is not limited to application to the structural details and component arrangements set forth in the following description or illustrated in the accompanying drawings. It should be understood that there is no. The invention can be in other embodiments and can be practiced or carried out in various ways. It is also to be understood that the terminology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including”, “comprising”, “having” and variations thereof herein includes items listed thereafter and equivalents thereof, As well as to include additional matters. Unless otherwise specified or limited, the terms “attached”, “connected”, “supported”, “coupled” and variations thereof are used in a broad sense and are both direct and indirect Includes attachment, connection, support and coupling. Further, the terms “connected” and “coupled” are not limited to physical or mechanical connections or couplings.

  [0041] A heat exchanger tube assembly 1 according to one embodiment of the present invention is shown in FIGS. Such a tube assembly 1 can be used in large heavy machinery such as excavators, mining trucks, generator sets, etc. as one of many individual tubes of a heat exchanger (eg, a radiator). However, it should be understood that the tube assembly 1 can be used in various types and sizes of heat exchangers.

  [0042] The tube assembly 1 comprises a tube 2 that extends from a first end 7 to a second end 8. The tube 2 forms a fluid flow conduit so that fluid (as an example, engine coolant) can be transferred through the tube assembly 1. As an example, the tube assembly 1 is used to dissipate waste heat from the flow of engine coolant, which is a flow like the flow of engine coolant passing through the tube 2 from one end 7, 8 to the other end 7, 8. Can be used with engine coolant radiators.

  [0043] The tube 2 includes a flat portion 3 located between the end portions 7 and 8. The flat part 3 (best described with reference to FIG. 11) comprises parallel first and second wide flat side surfaces 12. The wide flat side surfaces 12 are spaced apart from each other and are joined by two opposing and spaced apart narrow tube side surfaces 15. Although the narrow tube side 15 is illustrated in the exemplary embodiment as having an arcuate shape, in other embodiments, the narrow tube side 15 may be straight, or May have several other contour shapes. The two wide flat side surfaces 12 and the two narrow tube side surfaces 15 together form a continuous tube wall 25 of the fluid flow conduit and within the continuous tube wall 25 to allow fluid flow through the tube 2. A space is formed. Although not shown in the exemplary embodiment, in some cases, surface reinforcement or turbulence in the flow conduit to improve the heat transfer rate between the fluid passing through the tube 2 and the tube wall 25. It may be preferred that a structure is provided.

  [0044] Still referring to FIG. 11, the flat portion 3 of the tube 2 has a tube subdimension d1 defined as the distance between the faces facing the outside of the two wide flat side surfaces 12, and the two narrow side surfaces. Tube main dimension d2 defined as the distance between the 15 outermost positions. In some highly preferred embodiments, the major dimension d2 is several times larger than the minor dimension d1. As an example, the major dimension of the exemplary embodiment is nine times larger than the minor dimension.

  [0045] The tube assembly 1 further includes two intricate fin structures 10 disposed along the flat portion 3. The fin structure 10 includes a number of sides 16 that are alternately connected by tops 18 and valleys 17 (best seen in FIG. 3) such that each fin structure 10 has a generally sinusoidal shape. The fin structure 10 may be a simple type, as shown in FIG. 3, or may include additional structures to improve heat transfer, structural strength, durability, or combinations thereof. Good. As an example, in some embodiments, the fin structure 10 comprises a louver, protrusion, slit, lance, or other known structure for improving heat transfer and / or structural rigidity of the side 16. It may be. In other embodiments, edge hems may be provided at one or both ends of the fin structure 10 adjacent to the narrow tube side 15. Such edge hems are particularly beneficial in providing resistance to damage that may be caused by rock or other debris impacts.

  [0046] The tube assembly 1 is also provided with a plurality of thin side sheets 11. These side sheets 11 are parallel to the opposing wide flat side surface 12 of the tube 2 and are spaced equidistant therefrom on either side by the fin structure 10. For this reason, the side 16, the top 18 and the trough 17 of the fin structure 11 provide a plurality of thin webs to separate the sidesheet 11 from the continuous tube wall 25. The side seat 11 is generally planar, but may be provided with a structure such as a vent edge, for example, to provide rigidity and / or to assist in assembly.

  [0047] The space between the sides 16 provides a flow path for the fluid to be placed in heat transfer relationship with the fluid through the tube 2 so that heat can be exchanged between the two fluids. . As an example, ambient air may be directed through the flow path to cool the engine jacket coolant through the tube 2. However, it should be understood that the tube assembly 1 can be used to place various other fluids in a heat transfer relationship. Each of the flow paths between the side portions 16 is further formed by one of the valley portion 17 and the top portion 18 and one of the flat side surface 12 of the tube 2 and the substantially planar side sheet 11. Is done. By fully demarcating the flow paths in this way, fluid through these flow paths is prevented from prematurely exiting the flow paths, thus improving the heat transfer capability.

  [0048] Tube 2, fin structure 10 and sidesheet 11 are preferably joined together to provide good thermal contact between fluids to be placed in a heat transfer relationship and good structural integrity. Forming a monolithic structure to provide sexuality. Although various materials can be used to construct the tube assembly 1, in a highly preferred embodiment, the tube 2, the fin structure 10 and the sidesheet 11 are made of a metal with high thermal conductivity (eg, aluminum, Copper). These components may be joined together to form the tube assembly 1 by various processes including brazing, soldering, adhesive bonding, and the like.

  [0049] In order to promote good heat transfer between the fluids, it may be advantageous for the fin structure 10 and the sidesheet 11 to extend over the entire major dimension d2 of the flat portion 3. In some cases, the fin structure 10 and sidesheet 11 may extend slightly beyond the outer edge of the narrow tube side 15 to protect the fluid flow conduit from damage from rock or other debris impacts. It may be preferable.

  [0050] It has been found that by providing a uniformly very thin sidesheet 11, the tube assembly 1 is very strong (especially with respect to bending about the center of gravity axis in the tube main dimension d2). The fin structure 10 provides very little stiffness in this direction due to their intricate characteristics so that in the absence of the sidesheet 11, the continuous tube wall 25 bends about the center of gravity axis. It provides only resistance to things. Due to the relatively small minor dimension d1 of the flat tube portion 3, the resistance to bending about the center of gravity axis by the continuous tube wall 25 is very small by itself, and the center of gravity at a distance substantially larger than the minor dimension d1. The spacing of the sidesheet 11 from the axis provides substantial benefits.

[0051] The influence of the side seat 11 on the bending rigidity of the tube assembly 1 around the center of gravity axis in the tube main dimension d2 is that the moment of gravity of the inertia around the axis of the tube assembly 1 is compared with that of the tube 2 alone. (The fin structure 10 may be premised on not contributing to the center of gravity axis of the inertia other than by maintaining the offset of the side seat 11 from the flat side surface 12 of the tube 2). In an exemplary embodiment where the tube wall thickness is 0.8 mm, the side sheet thickness is 0.25 mm, the fin structure height is 6.55 mm, the minor dimension is 3.7 mm, and the major dimension is 23.27 mm. centroid moment of inertia around the tube main dimension axis of the tube assembly and tube alone, ^{respectively,} can be calculated as 925 mm 4, 76 mm ^4. In other words, the inertia of the center of gravity of the tube assembly about the tube main dimension axis is about 12 times that of the tube itself. In a preferred embodiment, the moment of gravity of the inertia of the tube assembly about the tube major dimension axis is at least 5 times that of the tube itself, and in a highly preferred embodiment it is at least 10 times. This is particularly preferred when the tube 2 is constructed from a material (eg an aluminum alloy) that exhibits a relatively low elastic modulus.

  [0052] The tube 2 of the exemplary embodiment further includes a first cylindrical portion 4 adjacent to the first end 7 and a second cylindrical portion 5 adjacent to the second end 8. ing. The flat portion 3 is disposed between the first cylindrical portion and the second cylindrical portion. By these cylindrical parts 4 and 5, the tube assembly 1 can be inserted into the receiving grommet (not shown) arrange | positioned at the header which opposes a heat exchanger with high reliability, without producing a leak. In order to maximize the amount of tubes available for effective heat exchange, the length of these cylindrical ends is preferably kept to a minimum and the length of the flats 3 is preferably tube. 90% or more of the total length of 2. The cylindrical portion 5 of the exemplary embodiment is provided with a circumferential bead 9 to restrict the tube assembly 1 from moving downwards when placed vertically on the heat exchanger.

  [0053] Although the embodiments shown in the accompanying drawings include cylindrical ends at both ends of the tube, in some cases, the tube assembly 1 does not include one or both of the cylindrical ends 4,5. It should be understood that it may be. If such a cylindrical end is not provided, the corresponding receiving grommet may be provided with a receiving opening corresponding to the shape of the continuous tube wall 25 in the flat part 3.

  [0054] In some preferred embodiments of the present invention, the heat exchanger tube assembly 1 includes an aluminum tube 2, first and second corrugated fin structures 10 made of aluminum, and first and second aluminum pieces. It is manufactured by forming a brazed joint between the second side sheet 11 and the second side sheet 11. The first corrugated fin structure 10 is disposed between the first side sheet 11 and the first wide flat side surface 12 of the tube 2, while the second corrugated fin structure 10 is disposed on the second side. Arranged between the sheet 11 and the second wide flat side surface 12 of the tube 2. The assembly is compressed to bring the top 18 and trough 17 of the fin structure 10 into contact with adjacent portions so that a brazed joint can be formed at the point of contact.

  [0055] A brazing material having a melting point lower than that of the tube 2, the fin structure 10 and the side sheet 11 is used to form the brazed joint. Such a brazing material is typically aluminum with a small amount of other elements (eg, silicon, copper, magnesium, zinc) added to lower the melting point. The brazing material may advantageously be provided as a coating on one or more components to be brazed. In some embodiments, both sides of the sheet material used to form the corrugated fin structure 10 are coated with a brazing material, thereby having the brazing material where joints are not needed or desirable. While avoiding, the necessary brazing material is provided at all points of contact where a brazed joint is required.

  [0056] Many methods can be used to raise the temperature of the tube 2, the fin structure 10 and the side sheet 11 to melt the brazing material to form a brazed joint, but two particularly preferred The methods are vacuum brazing and controlled atmosphere brazing. In vacuum brazing, the assembled parts are placed in a sealed furnace and substantially all of the air is removed to create a vacuum environment. In this process, when the part is heated and functions to break down the oxide film present on the outer surface of the component, the magnesium present in the alloy is released, whereby the molten brazing material is exposed to exposed aluminum. It becomes possible to be joined to. The oxide film is prevented from reforming and inhibiting metal bonding due to the absence of oxygen in the vacuum environment.

  [0057] In controlled atmosphere brazing, flux is applied to the components prior to heating. Part heating occurs in an inert gas environment to prevent the oxide film from re-forming after the flux reacts to replace the oxide film present on the mating surface on the part. When the oxide layer is replaced, the molten braze is joined to the exposed aluminum to form a brazed joint.

  [0058] It may be particularly preferred to braze several tube assemblies 1 at once to improve throughput in a product manufacturing environment. FIG. 6 shows a method according to an embodiment of the invention, in which four tube assemblies 1 are manufactured simultaneously. It should be understood that similar methods can be used to produce more than four tube assemblies, or fewer than four tube assemblies at a time.

  [0059] In the embodiment of FIG. 6, a tube 2, a corrugated fin structure 10, and a substantially planar side sheet 11 are provided. Each of the tubes 2 is disposed between a pair of corrugated fin structures 10, and each of the corrugated fin structures 10 is between one of the tubes 2 and one of the substantially planar side sheets 11. Be placed. Separator sheets 19 are disposed between adjacent pairs of substantially planar side sheets 11. The tube 2, the corrugated fin structure 10, and the substantially planar side sheet 11 are arranged to form a laminate 26. An additional separator sheet 19 is disposed adjacent to the substantially planar side sheet 11 at the outermost end of the laminate 26 and the adjacent top sheet 18 and valley 17 of the intricate fin structure are adjacent to the side sheet 11 and In order to contact the wide flat side surface 12 of the tube 2, a compressive load is applied to the laminate 26 in the stacking direction.

  [0060] In order to provide a uniform compressive load on the laminate 26, a highly rigid bar 21 (eg, general structural channel steel) may be used at the outermost end of the laminate 26. Good. The compressive load may be maintained by using a metal band 22 that surrounds the laminate 26 at several locations after the compressive load is applied to the laminate. The band 22 is tightened over the bar 21 in a state where the laminated body 26 is compressed, and as a result, the tension of the band 22 maintains the compression load. After being so assembled, the laminate 26 is placed in a brazing furnace to produce individual tube assemblies 1. The laminate 26 is heated in a furnace to a temperature suitable for melting the brazing material, after which the laminate 26 is cooled to resolidify the molten brazing material, thereby at the point of contact. A brazed joint is created. After cooling, the individual tube assemblies 1 (brazed into individual integrated structures) can be removed from the separator sheet 19. The separator sheet 19 may be coated to prevent metal bonding between the separator sheet 19 and the side sheet 11. Otherwise, even if no brazing material is present, such undesirable bonding occurs at the brazing temperature.

  [0061] When the laminate 26 is heated to the brazing temperature, thermal expansion of the metal material occurs in the laminate 26. In aluminum brazing, the component is typically heated to a brazing temperature of 550 ° C to 650 ° C. This temperature range is substantially higher than the temperature used for the soldering iron part, so the thermal expansion experienced by the components of the tube assembly 1 during the joining process is, when the component is aluminum, It is substantially larger than when the component is copper.

  [0062] The inventor should take care during the brazing process to ensure that the fin structure 10 does not distort by heating to brazing temperature and cooling back to ambient temperature. I found. Unlike conventional brazed aluminum radiator manufacturing, which includes multiple rows of tube and fin structures that are joined together into an integral brazed core, the side 16 of the fin structure 10 includes components of the tube assembly 1 and separators. It tends to be distorted by the shearing force generated by the difference in thermal expansion from the sheet 19. In some embodiments of the present invention, this problem is remedied by making the coefficient of thermal expansion of the separator sheet 19 substantially match that of the tube 2, fin structure 10 and side sheet 11. This can be accomplished by forming the separator sheet 19 from a similar aluminum alloy or other material that exhibits a similar coefficient of thermal expansion.

  [0063] Alternatively or in addition, multiple individual separator sheets 19 can be used between each adjacent tube assembly 1 as shown in FIG. A gap 20 is provided between adjacent ones of the individual separator sheets 19. If the separator sheet 19 is constructed from a material having a coefficient of thermal expansion that is substantially different from the material from which the tube 2, fin structure 10, and side sheet 11 are constructed, the gap 20 may cause heating of the laminate 26 and It may be increased or decreased during cooling, thereby substantially reducing distortion of the fin structure 10 that would otherwise be caused by a mismatch in thermal expansion coefficients. The gap 20 serves as a break to avoid the accumulation of thermal expansion induced strains, so that such strains are limited to discrete contact areas under each individual separator sheet 19. The assembly method shown in FIG. 7 can be particularly beneficial when a more heat resistant material (eg, stainless steel) is used for the separator sheet 19 and the components of the tube assembly 1 are formed from aluminum.

  [0064] The tube 2 will be described in more detail with particular reference to FIGS. As described above, the embodiment of the tube 2 shown in FIG. 8 includes the flat tube portion 3 positioned between the first cylindrical tube portion 4 and the second cylindrical tube 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 and 5. The transition region 6 provides a smooth and continuous flow path for fluid through the tube 2 and avoids mechanical stress concentration sites in the tube material.

  [0065] As shown in detail in the partial cross-sectional view of FIG. 10, the transition region 6 extends over a length L from a position 27 closer to the end 7 of the tube 2 to a position 14 farther from the end 7. Exist. The length L is preferably at least equal to the diameter of the cylindrical end 4, but in some alternative embodiments the size may be smaller than the diameter of the corresponding end. As can be seen in FIG. 8, the wide flat side surface 12 has a position 14 at one end such that at least a portion of the wide flat side surface 12 is located along the tube 2 between the position 27 and the position 14. Extends beyond. The positions 27 and 14 define the start point and the end point of the transition area 6.

  [0066] In a preferred embodiment, the intersection of the wide flat side surface 12 of the flat tube region 3 and the transition region 6 forms a curved path 13. These curved paths 13 beneficially reinforce the flat part 3 of the tube 2 with respect to the bending moment about the tube main dimension axis. For comparison, a prior art tube 102 is shown in FIG. The tube 102 includes a flat portion 103 joined to the cylindrical portion 104 via a transition portion 106. The common area of the transition part 106 and the flat part 103 forms a straight path 113 on the wide flat side surface 112 of the flat part 103. The straight path 113 extends the tube main dimension and is very easy to bend around the main dimension axis. This can be particularly harmful during installation and / or removal from the heat exchanger of the tube assembly including the tube 102. This is because, in such installations and such removals, this type of bending moment often acts on the tube. This problem is particularly exacerbated when the tube is constructed from a very low strength material (eg, annealed aluminum).

  [0067] The inventor counteracts the bending moment of the type described above and buckles or other damage to the tube 2 during installation, removal and other handling of the tube 2 or tube assembly 1 including the tube 2. In order to prevent this, it has been found that a substantial reinforcing effect is provided by the curved path 13. Although it can benefit from a non-linear path, it can be particularly beneficial that the path 13 be formed by a series of connected arcuate path segments.

  [0068] In the exemplary embodiment, each curved path 13 includes a tip located approximately at the center plane of the tube, so that the tip is located at a position 14 along the path 13. To do. The position 14 is the end 7 (in the case of a transition region between the flat portion 3 and the first cylindrical end 4) or the end 8 (the transition region between the flat portion 3 and the second cylindrical end 5). The most distant). The path 13 preferably comprises an arcuate path segment at the tip so that stress concentration is avoided at the tip.

  [0069] In some preferred embodiments, the outer periphery (that is, the outer periphery) of at least one of the two cylindrical portions 4 and 5 is smaller than the outer periphery of the continuous tube wall 25 in the flat portion 3. This advantageously provides a relatively large heat transfer surface area per unit length in the flat part 3 without requiring a correspondingly large diameter at one or both of the ends 7,8. Can do. For example, small diameters at these ends may be preferred because the spacing between adjacent tube assemblies can be reduced and the need for large sealing surfaces at these ends can be eliminated. In some preferred embodiments, the outer periphery of the flat portion 3 is at least 25% greater than the outer periphery of at least one of the two cylindrical ends.

  [0070] Heat exchangers with fluid transfer tubes having a flat shape over their entire length are well known in the art and have been used as radiators and the like for decades. This type of flat tube is usually constructed in one of two ways. They are extruded in a flat shape from a billet of material and / or withdrawn and cut into discrete lengths. Alternatively, they are produced from a rolled sheet in a tube mill by sheet form molding into a round shape, seam welding, roll flattening into a flat tube shape, and cutting into discrete tube lengths.

  [0071] In the case of a tube, such as a prior art tube 102 (FIG. 9), having a flat portion 103 and a cylindrical end 104, both ends of the flat tube are formed into a cylindrical shape so that the cylindrical end 104 and the transition portion 106 is formed. This process can be done quickly and easily when the tube is constructed from a malleable material (eg, copper) and only requires forming the extreme end of the tube 2. However, this method cannot obtain the transition part 6 as described above.

  [0072] The transition region 6 may be formed by first shaping the tube 2 into a round shape having an outer diameter equal to the desired outer circumference of the continuous tube wall 25 in the flat portion 3. Next, with particular reference to FIG. 12, both ends of the round tube 2 are reduced in diameter to form cylindrical ends 4,5 and the ends 4,5 and the central portion 3 that remains in the original round shape. A tapered transition region 6 ′ is formed between “and”. This reduction in diameter can be achieved, for example, by drawing the tube end. In some preferred embodiments, the ends are reduced in diameter by at least 20% to achieve the desired outer perimeter ratio between the flat portion 3 and the cylindrical ends 4,5.

  [0073] As shown in FIGS. 13A and 13B, the profile of the flat portion 3 of the tube 2 is such that the portion 3 'of the tube 2 is between the first half 22 of the mold and the second half 23 of the mold. Can be formed. The tube 2 is inserted between the mold halves 22, 23 when the mold is in the release position, ie when the two halves of the mold are spaced apart from each other as in FIG. 13A. When the tube 2 is so arranged, the mold is closed to the closed position of FIG. 13B, thereby forming the flat portion 3 of the tube 2 and having a sub dimension d1 and a main dimension d2. Optionally, a mandrel 24 may be placed in the tube 2 prior to the molding process to prevent buckling or other undesirable deformation of the wide flat side surface 12 during the molding process. In use, the mandrel 24 may be removed from the tube 2 after the molding process is complete. The surface shape of the transition region 6 can be produced by providing a complementary negative representation of the surface shape at the contact surface of the mold halves 22, 23, so that the desired shape of the transition region 6 in the molding process is achieved. A surface shape is formed to form the tube 2.

  [0074] An alternative embodiment of a tube assembly 201 according to the present invention is shown in FIGS. The tube assembly 201 has a number of features in common with the tube assembly 1 described above, and similar features of these two are given the same reference numerals. Tube assembly 201 includes two intricate fin structures 10 disposed along a flat portion 203 of multi-piece tube assembly 202. The side seat 11 is spaced equidistantly from the opposing wide flat side 212 of the flat portion 203 and the top and valleys of the intricate fin portion 10 are side-like in a manner similar to that described for the tube assembly 1. The sheet 11 and the wide flat side surface 212 are joined.

  [0075] The multi-piece tube assembly 202 includes a tube assembly central portion 232 (which forms a flat portion 203), a tube assembly end portion 230 disposed at one end of the central portion 232, and the central portion 232's A tube assembly end portion 231 disposed at the other end. Each of the tube assembly end portions 230, 231 has a cylindrical portion (204, 205, respectively) joined to the flat tube portion 233 via the transition portion 206. The flat tube portion 233 is substantially complementary in size and shape to the cross section of the flat tube portion 203. An opening 234 is provided at each end of the flat tube portion 233. Opening 234 is sized to receive a corresponding end of central portion 232. The joined tube assembly 202 provides a leak-free flow path for fluid between the first end 207 and the second end 208.

  [0076] As best seen in FIG. 16, the end of the central portion 232 received in the opening 234 of the end portion 230 can extend into the end portion by a predetermined distance, so that the central portion 232 The overlapping portion of the wall portion and the flat tube portion 233 of the end portion 230 is created. 16 with particular reference to end portion 230, it should be understood that the same applies to the opposite end portion 231. One beneficial aspect of such overlap is that the resulting local increase in total wall thickness in the overlap region increases the strength of the tube assembly 202 to withstand bending moments about the tube major dimension axis. Can do. In order to maximize such effects, in some embodiments, the end of the tube assembly central portion 232 extends to the transition 206 so that the overlapping walls are substantially the same as the flat tube portion 233. It may be preferred to be provided throughout.

  [0077] In order to further provide structural support to the tube assembly 202 in the flat tube portion 233, it may be preferred that the wall thickness of the end portions 230, 231 in the flat tube portion 233 is greater than the wall thickness of the central portion 232. is there. This minimizes resistance to heat transfer between fluids while maintaining adequate structural support in those areas that can be subjected to significant stress during tube assembly installation and / or removal as described above. In order to do so, the wide flat side 212 of the central portion 232 can be made relatively thin. The resulting reinforcement may be sufficient for the intended use of the tube assembly in at least some embodiments. In some other embodiments, the rigidity can be further increased by forming the intersection of the transition region 206 and the flat tube portion 233 as a curved path in the same manner as described above for the tube 2.

  [0078] In at least some embodiments, the central portion 232 may be formed by extruding an aluminum alloy with a mold to directly create the flat portion 203. Such an extrusion process allows the narrow side surfaces joining the wide flat side surfaces 212 to be thicker than the wide flat side surfaces 212 to further strengthen the tube assembly 202 structurally. Further, as an option, an internal web 235 may be provided that extends between the wide flat sides 212 for structural support and / or improved heat transfer. Although three such webs 235 are shown in FIG. 15, it should be understood that more or fewer webs may be desirable depending on the application. The web 235 can have a variety of shapes and orientations, including but not limited to, arched shapes and cornered shapes. In any case, the web 235, if present, is disposed between the narrow sides of the central tube portion 232 and divides the flow conduit extending through the central tube portion 232 into a number of parallel branches. .

  [0079] In general, the end portions 203, 231 may be formed in a manner similar to that described above with respect to the tube 2. In order to facilitate joining the central portion 231 to the end portions 230, 231 using a material having a brazing alloy that metalizes one side and the metallized side is located inside the end portion. The end portions 230 and 231 may be formed so that the end portions are formed in a state of being disposed in contact with the end portions of the central portion 232 in the overlapping region. Alternatively, the brazing alloy may be provided at the joint location in the form of a brazing alloy paste or ring. In any case, the sections 230, 231, 232 of the tube assembly 202 can be joined in a common brazing process by the joint of the complete tube assembly 201. Accordingly, such joining of the tube assembly 201 can be accomplished in a manner similar to that described above with respect to the tube assembly 1.

  [0080] Various alternatives to some features and elements of the invention have been described with reference to specific embodiments of the invention. Alternative process features, elements, and aspects described with reference to one particular embodiment, except for process features, elements, and aspects that are mutually exclusive or inconsistent with the embodiments described above. Note that is applicable to other embodiments.

  [0081] The embodiments described above and illustrated in the drawings are presented for illustrative purposes only and are not intended to limit the concepts and principles of the present invention. Thus, those skilled in the art will recognize that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Heat exchanger tube assembly 2 ... Tube 3 ... Flat part 4 ... 1st cylindrical part 5 ... 2nd cylindrical part 6 ... Transition part 7 ... 1st edge part 8 ... 2nd edge part 9 ... Circumferential direction Bead 10 ... Corrugated fin structure 11 ... Side sheet 12 ... Wide flat side surface 13 ... Curve path 14 ... Position 15 ... Narrow side surface 16 ... Side part 17 ... Valley part 18 ... Top part 19 ... Separator sheet 20 ... Gap 21 ... Bar 22, 23 ... Half 24 ... Mandrel 25 ... Continuous tube wall 26 ... Laminated body 27 ... Position 201 ... Tube assembly 202 ... Multi-piece tube assembly 203 ... Flat part 206 ... Transition part 207 ... First end 208 ... Second end 212 ... Wide flat side surface 230, 231 ... End part 232 ... Central part 233 ... Flat tube part 234 ... Opening 235 ... Web

Claims (20)

A tube assembly for a heat exchanger,
A flat portion having spaced apart first and second wide tube sides joined by oppositely spaced narrow sides; a first cylindrical portion at a first longitudinal end of the tube; and A tube having a second cylindrical portion at a second lengthwise end of the tube, and the flat portion is disposed between the first cylindrical portion and the second cylindrical portion,
The tube assembly further includes:
A first fin structure having a plurality of first corrugated tops and corrugated troughs connected by side portions;
A second fin structure having a plurality of second corrugated peaks and corrugated valleys connected by side portions;
First and second substantially planar side sheets,
The corrugated trough of the first fin structure is joined to the side of the first wide tube,
The corrugated top of the first fin structure is joined to the surface of the first substantially planar sidesheet;
The corrugated trough of the second fin structure is joined to the second wide tube side surface,
The corrugated top of the second fin structure is joined to the surface of the second substantially planar sidesheet. The tube assembly according to claim 1, wherein
The flat portion further includes one or more spaced webs disposed between the narrow tube side surfaces to join the wide tube side surfaces to each other. The tube assembly according to claim 1, wherein
The tube
A first tube portion having the flat portion;
A second tube portion having the first cylindrical portion and joined to a first end of the first tube portion;
A tube assembly comprising: a third tube portion having the second cylindrical portion and joined to a second end of the first tube portion. A tube assembly according to claim 3, wherein
The first tube portion is a tube assembly formed by extruding an aluminum alloy. The tube assembly according to claim 1, wherein
The spaced apart first and second wide tube sides have a first material thickness;
The first and second substantially planar sidesheets have a second material thickness,
The first material thickness is at least twice the second material thickness. A tube assembly for a heat exchanger,
A first tube assembly end portion having a cylindrical portion, a flat tube portion, and a transition between the cylindrical portion and the flat tube portion;
A second tube assembly end portion having a cylindrical portion, a flat tube portion, and a transition portion between the cylindrical portion and the flat tube portion;
A tube assembly central portion disposed between the first tube assembly end portion and the second tube assembly end portion, wherein the spaced apart parallel portions are joined by two spaced apart narrow sides. A tube assembly central portion having two wide flat sides, and
A first end of the tube assembly central portion is joined to the flat tube portion of the first tube assembly end portion;
A tube assembly in which a second end portion of the tube assembly central portion is joined to the flat tube portion of the second tube assembly end portion. The tube assembly according to claim 6, comprising:
The first tube assembly end portion, the second tube assembly end portion, and the tube assembly central portion are joined by brazing. The tube assembly according to claim 6, comprising:
The central portion of the tube assembly further comprises one or more spaced webs disposed between the spaced apart narrow sides to join the wide flat tube sides together. The tube assembly according to claim 6, comprising:
The flat tube portions of the first and second tube assembly end portions each include two spaced apart wide flat sides;
A common portion of each of the transition portions with the wide flat side surface forms a curved path tube assembly. The tube assembly according to claim 6, comprising:
The spaced apart parallel wide flat sides of the central portion of the tube assembly have a first wall thickness;
The flat tube portion of at least one of the first and second tube assembly end portions has a second wall thickness that is greater than the first wall thickness. The tube assembly according to claim 6, comprising:
The tube assembly central portion is partially received within the first and second tube assembly end portions. A tube assembly according to claim 11, comprising:
The first end of the tube assembly central portion extends to the transition portion of the first tube assembly end portion. A tube assembly according to claim 12, comprising:
The second end of the central portion of the tube assembly extends at least partially into the transition portion of the end portion of the second tube assembly. A method of manufacturing a heat exchanger tube assembly comprising:
Reducing the diameter of the round tube in a first portion of the round tube;
Flattening a second portion of the round tube adjacent to the first portion to form two wide flat sides spaced apart in the second portion;
Joining the second part to an end of a flat tube. 15. A method according to claim 14, comprising
And a step of forming the flat tube by extruding an aluminum alloy with a mold. 15. A method according to claim 14, comprising
Joining the second part to the end of the flat tube comprises:
Inserting the end of the flat tube into the second portion of the round tube;
Heating the flat tube and the round tube to a brazing temperature to melt a brazing alloy provided at an insertion position;
Cooling the flat tube and the round tube to form a solidified brazed joint between the flat tube and the second portion. The method according to claim 16, comprising:
The method further comprises the step of joining the first and second corrugated fin structures to opposite wide flat sides of the flat tube. The method of claim 17, comprising:
The method of joining the second portion to the flat tube and joining the first and second corrugated fins to the flat tube are performed using a single brazing process. 15. A method according to claim 14, comprising
Reducing the diameter of the round tube comprises forming a transition region at least partially between the first portion and the second portion. 20. The method according to claim 19, comprising
The step of planarizing the second portion includes forming a curved common portion between the wide flat side surface of the second region and the transition region.

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