JP2008145024A - Manufacturing method of flat heat transfer tube, flat heat transfer tube obtained by method, and gas cooling device incorporating flat heat transfer tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a flat heat transfer tube having high rigidity on a flat face, securing a wide heat transfer area, efficiently exchanging heat, and having high durability, and further to provide the flat heat transfer tube obtained by the manufacturing method, and a gas cooling device provided with the heat transfer tube. <P>SOLUTION: In this method of manufacturing the flat heat transfer tube by performing UO-forming to a square-shaped metallic thin plate, press molding is performed on parts where two sheets of metallic thin plates are joined to form flat faces in opposition to each other, to form a plurality of hollow ribs in advance, and then edge bending and folding by the UO-forming are performed to form the flat tube-shaped tube stoke, then an edge of the tube stock is butted over the whole length, and integrally joined. The flat heat transfer tube is obtained by the method, and further a gas cooling device provided with the heat transfer tube is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat transfer tube incorporated in a high-temperature gas cooling device represented by, for example, EGR gas, and more specifically, a flow path of a fluid composed of a high-temperature gas or the like that is incorporated in a heat exchange type cooling device. The present invention relates to a flat heat transfer tube manufacturing method that exhibits excellent heat exchange performance, a flat heat transfer tube obtained by the manufacturing method, and a high-temperature gas cooling device incorporating the heat transfer tube.

  In recent years, various kinds of liquid-liquid, liquid-gas, gas-gas, etc. such as EGR cooler for automobile exhaust gas recirculation, exhaust gas cooler, fuel cooler, oil cooler, intercooler, exhaust heat recovery heat exchanger, etc. Although heat exchangers for fluids in the form are frequently used, heat transfer tubes through which these fluids flow are variously devised to efficiently radiate or absorb the heat held by the fluids. Has been made. For example, a method of taking a part of exhaust gas from the exhaust system of a diesel engine, returning it to the intake system of the engine again, and adding it to the air-fuel mixture is called EGR (Exhaust Gas Recirculation) and is called NOx (nitrogen oxide) ), Reducing pump loss, reducing heat dissipation loss to the coolant due to lowering of combustion gas temperature, increasing specific heat ratio due to working gas volume / composition change, and accompanying improvement in cycle efficiency, etc. Therefore, it is widely adopted as an effective method for purifying exhaust gas from diesel engines and improving thermal efficiency.

  However, if the temperature of the EGR gas rises and the amount of EGR gas increases, the durability of the EGR valve deteriorates due to its thermal action, and there is a risk that it will break early. This leads to a phenomenon that the fuel efficiency is lowered due to the lowering of the charging efficiency as the intake air temperature rises. In order to avoid such a situation, a device for cooling EGR gas with engine coolant, car air-conditioner refrigerant or cooling air is used, and in particular, gas-liquid that cools EGR gas, which is a gas, with engine coolant. A number of heat exchange type EGR gas cooling devices have been proposed. Among these gas-liquid heat exchange type EGR gas cooling devices, a double structure that has a simple structure and can be easily installed even in a narrow installation space. There is still persistent demand for tube-type heat exchange type EGR gas cooling devices. For example, by installing corrugated fins and cross fins in the tube, the gas flow can be trickled to increase the contact area with the fins. Despite its simple and compact structure, the built-in double-tube heat exchanger has excellent cooling effect. There from where it can be expected, as a heat exchanger for EGR gas cooling with limited size automobiles installation space, have been put already numerous practical.

  However, the double pipe heat exchanger as described above has a limit in the absolute amount of fluid that flows because it is compact in structure, and as a result, the total heat exchange amount is insufficient. There were still challenges. As a high-temperature gas cooling device that solves this problem, a so-called shell-and-tube multi-tubular heat exchanger must be adopted even if the structure is somewhat complicated and the size must be increased. There have been a number of proposals for various types of containers, and various improvements have been made. For example, in the shell-and-tube multitubular heat exchanger 200 shown in FIG. 8A, a cooling water inlet 120 is provided at one end of the outer peripheral portion of the shell body 100 constituting the cooling jacket, and a cooling water outlet 121 is provided at the other end. And a bonnet 70 serving as an outlet port 90 for the EGR gas g subjected to heat exchange at the other end thereof, and at one end in the longitudinal direction of the shell body 100, A plurality of heat transfer tubes 10 are attached at intervals via tube sheets 30 that are provided integrally with each other and are attached to the inside of each bonnet 70, and high-temperature EGR gas g passes through the heat transfer tubes 10. It flows so as to intersect with the cooling water C flowing through the shell main body 100, and the heat exchange through the wall surfaces of the plurality of heat transfer tubes 10, High temperature introduced from the scan inlet 80 of the EGR gas g, and is configured to discharge cooled until reaching the gas outlet 90. The distance from the gas inlet to the outlet is limited in terms of equipment in terms of layout, and since it is desired to be shorter, the heat transfer tube serving as the gas flow path is required to have excellent heat exchange performance. However, in the above prior art, as shown in FIG. 5B, the convex groove 10-1 extending from the outer peripheral surface of the heat transfer tube 10 to the inner peripheral surface is formed in a spiral shape, thereby allowing It has been reported that turbulent flow is generated in the high-temperature EGR gas that is generated and carbon is prevented from being deposited to effectively promote heat exchange through the tube wall (see, for example, Patent Document 1).

  Further, in the heat transfer tube 10a shown in FIG. 9 (a), as shown in FIG. 9 (b), on the inner peripheral surface of the elementary tube 10a-2, a spiral shape substantially equal to the inner diameter of the elementary tube 10a-2 is formed. By inserting the formed flat fin 20 and forming the spiral groove 10a-1 on the wall surface of the raw tube 10a-2 in the inserted state of the fin 20, the inner peripheral surface of the raw tube 10a-2, A heat transfer tube in which both side edges 20-1 in the width direction of the spiral flat fin 20 are brought into contact with each other is disclosed (see, for example, Patent Document 2), and both side edges 20-1 of the fin 20 and the raw tube 10a- are disclosed. 2 is in line contact with the inner peripheral surface reliably, and at the same time, in the spiral portion, the contact area between the fin 20 and the element tube 10a-2 is increased to ensure excellent heat transfer, and the inserted spiral. In the heat transfer tube 10a by the action of the flat fin 20 The flow of fluid is turbulent and carbon deposition is further prevented, and coupled with the increase of the fluid flow distance in the heat transfer tube 10a, the contact time between the fluids through the inner wall surface of the tube is increased, which is excellent. It has been reported that high heat exchange performance can be obtained.

On the other hand, in another example of a multi-tube heat exchanger that is not shown, a plurality of flat tubes are stacked inside the shell body, and high-temperature EGR gas that flows through a flow path inside the flat tubes is used. A multi-tube EGR cooler that exchanges heat through the tube wall of the flat tube is known. The structures of the flat tubes 10b and 10c incorporated in the multi-tube EGR cooler are shown in FIG. This is disclosed in FIG. Here, the former flat tube 10b is composed of a first plate 10b-1 and a second plate 10b-2 as shown in FIG. 10A, and a rectangular cross section having a corrugated shape in the longitudinal direction between the two plates. The channel-shaped fins 20a are inserted, and portions of the first plate 10b-1 and the second plate 10b-2 corresponding to the wavy ridge lines of the channel-shaped fins 20a are respectively formed in the turbulent flow forming portions 10b- 3, the turbulent flow forming portion 10b-3 has a plurality of concave or convex portions formed in a hemispherical shape, and in the case of the flat tube 10c, the turbulent flow forming portion 10b-3 is shown in FIG. Thus, the turbulent flow forming portion 10c-3 formed in the first plate 10c-1 and the second plate 10c-2 is composed of a plurality of recesses formed in the width direction of both plates, and each turbulent flow is formed. Part 1 By appropriately adjusting the size, depth, etc. of b-3 and 10c-3, turbulence is generated in the high-temperature exhaust gas flowing through the flat tubes 10b and 10c, and at the same time, it flows through the outside thereof. It has been reported that excellent heat exchange performance was obtained by promoting appropriate stirring action in cooling water or the like (see, for example, Patent Document 3).
JP-A-11-108578 JP 2002-295987 A JP 2004-263616 A

  In each of the prior arts described above, in the multi-tube heat exchanger disclosed in Patent Documents 1 and 2, a spiral ridge is provided on the inner peripheral surface of the heat transfer tube provided therein, or the spiral ridge is provided. It has been reported that by inserting flat fins in contact with the gas, turbulence was generated in the gas flow, and in addition, the contact area was increased, resulting in excellent heat exchange performance. Since the heat tube itself is basically a cylindrical tube, the contact area is naturally limited, and in order to expand the contact area and realize better heat exchange efficiency and low pressure loss, the heat transfer tube built in As a flat tube, the multi-tube heat exchanger disclosed in Patent Document 3 also employs a flat tube as an individual heat transfer tube that is built in to form a heat transfer tube group, and the inner tube is installed in the flat heat transfer tube. Fin structure as a fin However, since it is a corrugated plate fin with a rectangular cross section and a corrugated free shape formed in the longitudinal direction, the flow path of the high-temperature fluid that is the cooling medium is divided into a plurality of small flow paths, and the flow is The heat transfer area is increased by meandering, and the ridge portion of the corrugation in the fluid flow direction is used as a turbulent flow forming portion. Since the projections and depressions are scattered, initial results have been achieved in terms of heat exchange efficiency.

  However, the corrugated inner fin as described above, for example, is provided on the inner peripheral surface, and the flat heat transfer tube in a state of being integrally joined maintains the rigidity of the inner fin itself instead of the rib structure. In the manufacturing process of a flat tube formed by roll forming or press forming on a thin metal plate having a thickness of 0.4 to 0.5 mm, the flat tube itself does not have sufficient rigidity. In addition, when the flat tube is formed wider so as to increase the heat transfer area, the flat tube has a higher flattening ratio, and the rigidity of the wall surface is further reduced. As a result, the shape becomes unstable, and the shape does not match during the ASSY process or the like, and there is a fear that sufficient bonding cannot be performed. In addition, due to the low rigidity of the flat tube, the wall surface is swelled and the flatness is deteriorated, and a gap is formed between the inserted fin and the flat tube wall surface. However, unsolved problems remain, such as inconvenience that bonding between the two becomes insufficient and heat transfer to the flat tube wall surface through the fins is reduced. As a result of various investigations aimed at establishing a manufacturing method of a flat heat transfer tube that can solve such problems and have a wide contact area while ensuring high rigidity of the wall surface, the flat tube is Since its wall surface plays the role of a rib structure in its structure, the rigidity in the longitudinal direction is maintained at a high level, but it is noted that it does not have sufficient strength in the width direction, particularly torsion. A hollow recess is provided so as to form a rib in advance in order to ensure its rigidity, and the hollow recess is formed in a perpendicular state or a skew state with respect to the longitudinal direction of the flat tube. Flatness that can maintain sufficient rigidity while ensuring excellent heat transfer performance by forming so as to protrude from the inside to the outside so as not to hinder the bonding with the fins installed on the inner wall surface of the flat tube Heat transfer tube And completed the present invention have found a production method. That is, the present invention provides a method for producing a flat heat transfer tube capable of maintaining high rigidity while ensuring excellent heat exchange performance and low flow resistance by having a wide heat transfer area, and a flat heat transfer obtained by the production method. The present invention provides a heat tube and a gas cooling device incorporating the heat transfer tube.

  In order to solve the above problems, a flat heat transfer tube manufacturing method according to the present invention is a method of manufacturing a flat heat transfer tube by UO forming on a rectangular metal thin plate. A plurality of hollow ribs are formed in advance by press molding at each portion where a flat surface is formed facing each other, and then a flat tubular element tube is formed by performing edge bending and bending by UO forming. Then, in the manufacturing method in which the edge of the element tube is butted over the entire length and joined as a unit, and the method of manufacturing the flat heat transfer tube by applying UO forming to a rectangular metal thin plate, After pre-bending the thin plate by UO forming, the two metal thin plates are combined to form a flat surface facing each other. A plurality of hollow ribs are formed in each part by press forming, and then a flat tubular element tube is formed by bending by UO forming, and then the edge of the element tube is pushed over the entire length. The method of combining and joining together is a characteristic constituent requirement.

  In the method for manufacturing a flat heat transfer tube according to the present invention, the hollow rib is formed simultaneously with edge bending by UO forming.

  Furthermore, in the method for manufacturing the flat heat transfer tube according to the present invention, it is preferable that the joining is performed by high energy beam welding.

  The method for manufacturing the flat heat transfer tube according to the present invention also includes that a fin member is internally provided, a brazing material is supplied together with the fin member, and an internal fin is formed when the flat tubular element tube is formed by the UO forming. The member is brazed to the inner surface of the flat heat transfer tube.

  In the method of manufacturing the flat heat transfer tube according to the present invention, the hollow rib is further formed to be linear or curved with a right angle or a predetermined angle with respect to the tube axis in the longitudinal direction of the flat heat transfer tube. It is characterized by this.

  In the method for manufacturing a flat heat transfer tube according to the present invention, the hollow rib is formed in one row or a plurality of rows with respect to a tube axis in a longitudinal direction of the flat heat transfer tube.

  Further, in the method for manufacturing a flat heat transfer tube according to the present invention, at least two of the hollow ribs are formed so as to intersect each other between the opposing flat surfaces of the flat heat transfer tube. It is.

  Furthermore, in the method for manufacturing the flat heat transfer tube according to the present invention, the hollow ribs are formed with mutually different phases between the flat surfaces facing the flat heat transfer tube.

  The method for manufacturing a flat heat transfer tube according to the present invention is also characterized in that the hollow ribs are formed to incline in opposite directions between flat surfaces facing each other.

  The flat heat transfer tube for a high-temperature gas cooling device according to the present invention for solving the above-mentioned problems is characterized in that the flat heat transfer tube manufactured by any one of the manufacturing methods described above is a characteristic component.

  The high-temperature gas cooling device according to the present invention for solving the above-described problems is characterized in that at least one or more of the flat heat transfer tubes are integrally incorporated.

  In the high-temperature gas cooling device according to the present invention, the high-temperature gas is an EGR gas.

According to the above-described flat heat transfer tube according to the present invention, in the method of manufacturing a flat heat transfer tube by performing UO forming on a rectangular metal thin plate, the two metal thin plates are combined to face each other. After forming a plurality of hollow ribs in advance by press molding at each site where a flat surface is formed, and then performing edge bending by UO molding to form a flat element tube, The end edges are butted together over the entire length and joined together by high energy beam welding, and the metal thin plates are subjected to edge bending by UO forming in advance, and then the two metal thin plates are joined together. A plurality of hollow ribs are formed by press molding at each portion where a flat surface is formed opposite to each other, and then bent by UO forming. It is a basic constituent requirement to form a flat tubular element tube and then abut the end edges of the element tube over their entire length and join them together, but the width direction of the metal thin plate forming the flat element tube In addition, by providing a plurality of hollow ribs so as to intersect at right angles to the tube axis in the longitudinal direction of the element tube, the rigidity of the flat surface at the time of so-called UO forming is increased, and the butt at the side edge in the longitudinal direction is increased. Is stable, and subsequent high-energy beam welding and ASSY work proceed smoothly, and the reliability of joining is significantly improved. In addition, the flat tube has a high rigidity on the flat surface and its shape is stable, so that it is possible to manufacture a flat heat transfer tube with a wider width and a larger contact area. As a result, excellent heat transfer properties can be secured, and a flat heat transfer tube with even greater rigidity and excellent durability can be obtained. Furthermore, thinning is achieved by increasing the rigidity, and a lightweight and high performance flat heat transfer tube can be obtained. Furthermore, in the present invention, a hollow rib is provided across the small flow paths divided by the fin structure on the flat surface of the inner wall portion of the flat tube, so that, for example, EGR gas or the like flowing between the flow paths The high-temperature fluid can flow between adjacent flow paths, the pressure loss of the fluid is reduced, the flow velocity distribution becomes uniform, and a flat heat transfer tube having exceptionally excellent heat exchange performance can be obtained. .
Furthermore, according to the manufacturing method of the present invention, when UO forming is performed on a metallic thin plate, whether the hollow rib is formed in advance by press forming or whether the hollow rib is formed by press forming simultaneously with UO forming. Any one of these can be selected arbitrarily, so that the manufacturing process can be simplified and simplified, and the processing cost can be greatly reduced. Can be manufactured.
The flat heat transfer tube according to the present invention thus manufactured is not only a heat transfer tube for a multi-tube heat exchanger disposed in an EGR gas recirculation system, but also an exhaust gas cooler, an EGR gas cooler, and a fuel cooler. It can be suitably installed as heat exchanger tubes for heat exchangers such as oil coolers and intercoolers, and at the same time, the above-described cooler with flat heat transfer tubes according to the present invention can reduce the size and weight of these devices due to its excellent heat exchange performance. Thus, it is possible to provide a heat exchange type cooling device that contributes to downsizing of the device and can be easily installed in a limited space at a relatively low cost.

    Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings and examples. However, the present invention is not restricted thereby, and design changes can be freely made within the scope of the gist of the present invention. Is possible.

  FIG. 1 is a perspective view showing a single unit of a flat heat transfer tube with a fin structure according to a first embodiment of the present invention. FIG. 2 shows a flat heat transfer tube with a fin structure according to a second embodiment of the present invention. 3 is a perspective view showing a single unit of a flat heat transfer tube according to a third embodiment of the present invention, FIG. 4 is a perspective view showing a single unit of a flat heat transfer tube according to a fourth embodiment of the present invention, FIG. FIG. 5 is a perspective view showing a single unit of a flat heat transfer tube according to a fifth embodiment of the present invention. FIG. 6 shows a first embodiment of a method for manufacturing a flat heat transfer tube according to the present invention. Is a perspective view schematically showing the manufacturing process, FIG. 7 is a second embodiment of a method for manufacturing a flat heat transfer tube according to the present invention, and FIGS. 7A to 7E schematically show the manufacturing process. It is a perspective view.

The flat heat transfer tube according to the present invention is basically composed of a rectangular metal thin plate, for example, a fixed coil or a long coil having a constant width is cut into a square having a predetermined dimension, and the resulting thin metal plate is used. It is formed by applying UO forming to a plate material. As a standard or long coil as the material, the plate thickness is usually 0.1 to 0.7 mm, preferably about 0.3 to 0.5 mm. An austenitic stainless steel such as SUS304, SUS304L, SUS316, or SUS316L is appropriately selected and employed.
As a method of manufacturing a flat heat transfer tube using a metal thin plate made of, for example, SUS304L austenitic stainless steel that has been selected and cut to a predetermined size, the manufacturing procedure as the first embodiment is shown in FIG. As shown in the drawing, first, the plate material 2e cut into a square shape shown in FIG. 5A is press-formed, so that it intersects at right angles to the longitudinal direction of the plate material 2e as shown in FIG. In this way, a plurality of hollow ribs 2e-1 are formed in a straight line, and then edge bending is performed on the side edge 2e-5 of the plate 2e, and then the plate subjected to the edge bending is subjected to UO forming. 2e is folded in half from the bent portion 2e-6 at the center in the longitudinal direction, and both end edges 2e-7 of the side edge 2e-5 are brought close to each other. As shown in FIG. 5C, a flat tubular element 1e-a is formed, and then the abutting portion 2e-2 formed by abutting the both end edges 2e-7 with each other is used as a high energy beam. A flat heat transfer tube 1e according to the present invention is manufactured as shown in FIG.

  Further, as shown in FIG. 7, the manufacturing procedure as the second embodiment is the same by applying UO forming to the side edge 2e-5 of the plate 2e cut into a square shape shown in FIG. As shown in FIG. (B), edge bending is performed in advance, and then, as shown in FIG. (C), a plurality of straight lines are formed so as to intersect at right angles to the longitudinal direction of the plate material 2e subjected to edge bending. The hollow rib 2e-1 is formed, and then the plate member on which the hollow rib 2e-1 is formed is folded in two from the bent portion 2e-6 at the center in the longitudinal direction of the plate member 2e by UO forming, and the side edge The two end edges 2e-7 of the portion 2e-5 are brought close to each other in the direction of abutting each other to form a flat tubular element tube 1e-a, as shown in FIG. By matching each other The butted portion 2e-2 which is formed by joining integrally by a high-energy beam welding for producing a flat heat exchanger tube 1e according to the invention as shown in FIG. (E).

  In said embodiment, the said hollow rib 2e-1 formed by press molding with respect to the board | plate material 2e is formed so that it may protrude toward the outer wall surface 2e-4 from the inner wall surface 2e-3 in the manufactured flat heat exchanger tube 1e. The inner wall surface 2e-3 is formed so as to be recessed from the flat surface, and the outer wall surface 2e-4 is formed so as to protrude in a convex shape. With such a structure, the inner peripheral portion of the flat tube 1e For example, when a corrugated fin structure having a cross-sectional channel shape (not shown) is installed and joined by brazing, uniform contact and joining are ensured by maintaining the inner wall surface 2e-3 in a flat state. Excellent heat transfer through the wall surface is ensured. In addition, it is firmly joined with high reliability, and the rigidity of the heat transfer tube itself is further increased and its durability is combined. It is coercive. On the other hand, the convex part formed on the outer wall surface 2e-4 of the flat heat transfer tube 1e by the hollow rib 2e-1 causes a turbulent flow and a vortex flow as appropriate to the flow of a cooling medium such as engine cooling water, The stirring effect contributes to the improvement of cooling efficiency. In the above embodiment, the hollow rib 2e-1 is formed by press molding before the edge bending process for the side edge 2e-5. However, the hollow rib 2e-1 is formed and the edge bending process is performed. However, it is also possible to form the flat element tube 1e by performing the UO forming after performing both at the same time. Further, if desired, when the flat element tube 1e-a is formed by the above UO forming, it is possible to incorporate a fin structure together, and the formed hollow rib 2e-1 is the longitudinal length of the flat heat transfer tube 1e. It can be provided so as to be inclined at a predetermined angle with respect to the tube axis in the direction, or can be provided in a curved shape.

  The above-described flat heat transfer tube obtained by the present invention is incorporated in various heat exchangers, for example, set in a gas flow path in an EGR gas recirculation system or the like, and used in a gas cooling device or the like for cooling high-temperature EGR gas. However, the flat heat transfer tube according to the present invention has a higher secondary moment on the flat tube wall surface due to the action of the hollow rib formed on the wall surface, thereby maintaining excellent rigidity, and a wider heat transfer area. As well as being able to ensure stability, heat transfer is efficiently promoted by the flow of EGR gas through the hollow ribs, so the above gas cooling device incorporating this promotes heat exchange more effectively As a result, it exhibits excellent heat exchange performance and can contribute to a reduction in size and weight of the cooling device and a significant reduction in energy loss.

The flat heat transfer tube 1 according to the first embodiment of the present invention includes a rectangular material made by cutting a regular coil made of SUS304 austenitic stainless steel having a thickness of 0.4 mm and a predetermined width into a predetermined dimension in advance. The plate 2 is made of a thin metal plate, and the two plates 2 are combined to face each other to form a flat surface, which is formed in the flat heat transfer tube 1 as shown in FIG. In this case, press forming is performed so as to protrude from the portion corresponding to the inner wall surface 2-3 toward the outer wall surface 2-4, and a predetermined interval is provided in the lateral width direction of the plate member 2, and the flattening is performed. A plurality of hollow ribs 2-1 having a predetermined height were formed in a straight line so as to intersect at right angles to the tube axis corresponding to the longitudinal direction of the tube 1. Further, in this embodiment, simultaneously with the formation of the hollow rib 2-1, the side edge 2-5 of the plate member 2 is subjected to edge bending, and then folded into two folds around the bent portion 2-6. Forming was performed, and both end edges 2-7 of the plate member 2 were butted to form a flat tubular element tube.
In this embodiment, when forming the flat element tube, the corrugated fins 3 having a cross-sectional channel shape are inserted as shown in FIG. Simultaneously with the joining of the part 2-2, the flat tube inner wall surface 2-3 was brazed and joined together. At this time, the abutting portion 2-2 at the edge 2-7 coincides over the entire length, and is joined with extremely high accuracy by high energy beam welding such as laser welding, electron beam welding, plasma welding, TIG welding, It was confirmed that the brazing of the corrugated fins 3 to the flat tube inner wall surface 2-3 was also joined in a uniform state with no gaps. In the flat heat transfer tube 1 according to this embodiment manufactured in this way, the deformation due to the twist in the lateral width direction is eliminated by the formation of the hollow rib 2-1, and the flat surface of the inner wall surface 2-3 is in a healthy state. As a result, the wave-shaped fins 3 are joined to the wall surface 2-3 with extremely high accuracy and in a uniform state, so that the rigidity of the obtained flat heat transfer tube 1 is maintained at a high level, and is robust and reliable. It was confirmed that it was finished in a flat tube excellent in Furthermore, it was also proved that the flat heat transfer tube 1 obtained by the present example was extremely easy to assemble because the mutual hollow ribs 2-1 served as a spacer even in the ASSY process. The flat heat transfer tube 1 according to the present embodiment thus obtained is mounted on a multi-tube heat exchanger (not shown) and incorporated in a gas cooling device for a gas flow path in an EGR system to cool the EGR gas. As a result of the test, the high-temperature EGR gas flowing through the heat transfer tube 1 is effectively transferred through the wide heat transfer area and the fin structure 3 provided therein, and at the same time, the flow formed into a waveform. In the passage, the pressure loss can be kept extremely low, and fluid can flow between adjacent flow paths through the recess formed by the hollow rib 2-1, and a uniform flow velocity distribution is maintained. In this state, it was confirmed that effective stirring was repeated and heat was exchanged efficiently, and excellent cooling performance was obtained.

The hollow ribs 2a-1 formed by press molding intersect at right angles to the tube axis corresponding to the longitudinal direction of the flat heat transfer tube 1a obtained as shown in FIG. 2 between the flat surfaces facing each other of the plate 2a. Thus, a flat heat transfer tube 1a was manufactured in substantially the same manner as in Example 1 except that a plurality of hollow ribs 2-1 having a predetermined height were formed in a curved shape. It was confirmed that the rigidity of the obtained flat heat transfer tube 1a was further enhanced and the heat transfer performance was sufficiently excellent.
In addition, the flat heat transfer tube 1a according to the present embodiment obtained in this way is attached to a multi-tube heat exchanger (not shown), and the gas cooling device for the gas flow path in the EGR system similar to the first embodiment is used. As a result of the incorporation and the EGR gas cooling performance test under the same conditions as in Example 1, it was confirmed that the same excellent cooling performance as in Example 1 could be obtained in this example.

Except for the fact that the hollow ribs 2b-1 formed by press forming are formed in a predetermined interval at three sets, each intersecting linearly as shown in FIG. 3, between the opposing flat surfaces of the plate 2b. A flat heat transfer tube 1b was produced in the same manner as in Example 1 above. It was confirmed that the rigidity of the obtained flat heat transfer tube 1b was further strengthened and the heat transfer performance was sufficiently excellent.
In addition, the flat heat transfer tube 1b according to the present embodiment obtained in this way is attached to a multi-tube heat exchanger (not shown), and the gas cooling device for the gas flow path in the EGR system similar to the first embodiment is used. As a result of the incorporation and the EGR gas cooling performance test under the same conditions as in Example 1, it was confirmed that the same excellent cooling performance as in Example 1 could be obtained in this example.

The hollow rib 2c-1 formed by press molding is inclined at a predetermined angle with respect to the tube axis in the longitudinal direction of the flat heat transfer tube 1c formed as shown in FIG. 4 between the flat surfaces facing each other of the plate 2c. A flat heat transfer tube 1c was manufactured in substantially the same manner as in Example 1 except that two rows were formed at predetermined intervals. It was confirmed that the rigidity of the obtained flat heat transfer tube 1c was sufficiently strengthened and sufficiently excellent in heat transfer performance.
Further, the flat heat transfer tube 1c according to the present embodiment obtained in this way is attached to a multi-tube heat exchanger (not shown), and the gas cooling device for the gas flow path in the EGR system similar to the first embodiment is used. As a result of the incorporation and the EGR gas cooling performance test under the same conditions as in Example 1, it was confirmed that the same excellent cooling performance as in Example 1 could be obtained in this example.

The hollow rib 2d-1 formed by press molding is inclined at a predetermined angle with respect to the tube axis in the longitudinal direction of the flat heat transfer tube 1d formed as shown in FIG. 5 between the opposing flat surfaces of the plate 2d. Thus, a flat heat transfer tube 1d was manufactured in substantially the same manner as in Example 1 except that two rows were formed at predetermined intervals and at the same time the phase was changed between the opposing flat surfaces. It was confirmed that the rigidity of the obtained flat heat transfer tube 1d was further enhanced and the heat transfer performance was sufficiently excellent.
Further, the flat heat transfer tube 1d according to the present embodiment obtained in this way is attached to a multi-tube heat exchanger (not shown), and the gas cooling device for the gas flow path in the EGR system similar to that of the first embodiment is used. As a result of the incorporation and the EGR gas cooling performance test under the same conditions as in Example 1, it was confirmed that the same excellent cooling performance as in Example 1 could be obtained in this example.

As described in detail in the above embodiment and each example, the flat heat transfer tube according to the present invention is in the transverse width direction of the thin metal plate forming the flat element tube with respect to the tube axis in the longitudinal direction of the element tube. Basically, a plurality of hollow ribs are provided so as to intersect at right angles, but this improves the rigidity of the flat surface at the time of so-called UO forming, and the butt at the edge in the longitudinal direction is stably integrated. In addition, the subsequent high energy beam welding and ASSY operations proceed smoothly, and the reliability of bonding is significantly improved. In addition, since the flat surface of the flat tube has high rigidity and its shape is stable, it is possible to manufacture a flat heat transfer tube with a wider width and a larger cross-sectional area of the tube, and brazing with the fin structure incorporated therein. It is possible to obtain a flat heat transfer tube that is uniformly performed to ensure excellent heat transfer properties and that has even greater rigidity and excellent durability. Furthermore, by providing a hollow rib across the small flow paths divided by the fin structure on the flat surface of the inner wall portion of the flat tube, a high-temperature fluid such as EGR gas flowing between the flow paths is adjacent to the flat flow path. Therefore, it is possible to obtain a flat heat transfer tube having a particularly excellent heat exchange performance by reducing the pressure loss of the fluid and making the flow velocity distribution uniform.
The effect of the present invention will be further described. When the flat tube is manufactured by UO forming for a thin metal plate, the hollow rib is formed by press forming in advance, or the hollow rib is formed by press forming simultaneously with UO forming. Can be arbitrarily selected, and the manufacturing process can be simplified and simplified to greatly reduce the processing cost. The flat heat transfer tube according to the present invention thus manufactured is not only a heat transfer tube for a multi-tube heat exchanger disposed in a cooled EGR system, but also an exhaust gas cooler, an EGR gas cooler, a fuel cooler, an oil Each of the above cooling devices equipped with a flat heat transfer tube according to the present invention can be suitably mounted as a heat exchanger tube for a heat exchanger such as a cooler, an intercooler, a waste heat recovery heater, etc. Since it is possible to reduce the size and weight of the apparatus, contribute to the downsizing of the apparatus, and provide a heat exchange type gas cooling apparatus that can be easily installed in a limited space at a relatively low cost. It is expected to be widely used in the industry.

It is a perspective view which shows the single body of the flat heat exchanger tube which equipped the fin structure by 1st Example which concerns on this invention internally. It is a perspective view which shows the single body of the flat heat exchanger tube which equipped the fin structure by 2nd Example which concerns on this invention internally. It is a perspective view which shows the single body of the flat heat exchanger tube by 3rd Example concerning this invention. It is a perspective view which shows the single body of the flat heat exchanger tube by 4th Example concerning this invention. It is a perspective view which shows the single body of the flat heat exchanger tube by 5th Example which concerns on this invention. 1st Example of the manufacturing method of the flat heat exchanger tube which concerns on this invention is shown, (a)-(d) is a perspective view which shows the manufacturing process typically. 2nd Example of the manufacturing method of the flat heat exchanger tube which concerns on this invention is shown, (a)-(e) is a perspective view which shows the manufacturing process typically. The multi-tube heat exchanger by a prior art example is shown, (a) is the partially broken vertical side view, (b) is the principal part expansion perspective view of the heat exchanger tube single-piece | unit internally equipped in said heat exchanger. FIG. 7 is a perspective view showing a principal part of a heat transfer tube according to another conventional example, and FIG. 5B is a perspective view showing a fin insertion process in the heat transfer tube. The flat heat exchanger tube by another conventional example is shown, (a) is the disassembled perspective view, (b) is the disassembled perspective view of the flat heat exchanger tube in still another conventional example.

Explanation of symbols

1, 1a, 1b, 1c, 1d, 1e Flat heat transfer tube 2, 2a, 2b, 2c, 2d, 2e Plate material 2-1, 2a-1, 2b-1, 2c-1, 2d-1, 2e-1 Hollow Ribs 2-2, 2a-2, 2b-2, 2c-2, 2d-2, 2e-2 Butting sections 2-3, 2a-3, 2b-3, 2c-3, 2d-3, 2e-3 Inner wall 2-4, 2a-4, 2b-4, 2c-4, 2d-4, 2e-4 Outer wall 2-5, 2a-5, 2b-5, 2c-5, 2d-5, 2e-5 Side edges 2-6, 2a-6, 2b-6, 2c-6, 2d-6, 2e-6 Bending portions 2-7, 2a-7, 2b-7, 2c-7, 2d-7, 2e- 7 End edge 3, 3a, 3b, 3c, 3d, 3e Fin structure 3-1, 3a-1, 3b-1, 3c-1, 3d-1, 3e-1

Claims (15)

  In a method of manufacturing a flat heat transfer tube by performing UO forming on a rectangular metal thin plate, a press is applied to each portion where two metal thin plates are combined to form a flat surface opposite to each other. A plurality of hollow ribs are formed in advance by forming, and then a flat tubular element tube is formed by performing edge bending and bending processes by UO forming, and then the edges of the element tube are butted together over the entire length, A method of manufacturing a flat heat transfer tube, wherein the flat heat transfer tubes are joined together.   In a method of manufacturing a flat heat transfer tube by performing UO forming on a rectangular metal thin plate, the metal thin plate is preliminarily bent by UO forming and then the two metal thin plates are combined. A plurality of hollow ribs are formed by press molding at each portion where a flat surface is formed opposite to each other, and then a flat tubular element tube is formed by bending by UO forming; After that, the manufacturing method of the flat heat transfer tube is characterized in that the end edges of the raw tube are butted together over the entire length and joined together.   The method of manufacturing a flat heat transfer tube according to claim 1 or 2, wherein the formation of the hollow rib is performed simultaneously with edge bending by UO forming.   The method for manufacturing a flat heat transfer tube according to any one of claims 1 to 3, wherein the joining is performed by high energy beam welding.   The method for manufacturing a flat heat transfer tube according to any one of claims 1 to 4, wherein a fin member is internally provided when the flat tubular element tube is formed by UO forming.   The method for manufacturing a flat heat transfer tube according to any one of claims 1 to 5, wherein a brazing material is supplied together with the fin member.   The method for manufacturing a flat heat transfer tube according to any one of claims 1 to 6, wherein the fin member provided inside is brazed to the inner surface of the flat heat transfer tube.   8. The hollow rib according to claim 1, wherein the hollow rib is formed at a right angle or a predetermined angle with respect to a tube axis in a longitudinal direction of the flat heat transfer tube, and is formed in a linear shape or a curved shape. 2. A method for producing a flat heat transfer tube according to item 1.   The method for manufacturing a flat heat transfer tube according to any one of claims 1 to 8, wherein the hollow ribs are formed in one row or in a plurality of rows with respect to a tube axis in a longitudinal direction of the flat heat transfer tube.   The flat transmission according to any one of claims 1 to 9, wherein at least two of the hollow ribs are formed so as to intersect each other between flat surfaces facing each other of the flat heat transfer tube. Manufacturing method of heat tube.   The method of manufacturing a flat heat transfer tube according to any one of claims 1 to 10, wherein the hollow ribs are formed with mutually different phases between flat surfaces of the flat heat transfer tubes facing each other.   The manufacturing of a flat heat transfer tube according to any one of claims 1 to 11, wherein the hollow ribs are formed to incline in opposite directions between flat surfaces of the flat heat transfer tube. Method.   A flat heat transfer tube for a high-temperature gas cooling apparatus, which is obtained by the manufacturing method according to any one of claims 1 to 12.   A cooling device for high-temperature gas, wherein at least one of the flat heat transfer tubes is incorporated.   The high-temperature gas cooling device according to claim 14, wherein the high-temperature gas is EGR gas.

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