EP0175743B1 - Method of manufacturing hairpin configured tubes - Google Patents

Method of manufacturing hairpin configured tubes Download PDF

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Publication number
EP0175743B1
EP0175743B1 EP85901607A EP85901607A EP0175743B1 EP 0175743 B1 EP0175743 B1 EP 0175743B1 EP 85901607 A EP85901607 A EP 85901607A EP 85901607 A EP85901607 A EP 85901607A EP 0175743 B1 EP0175743 B1 EP 0175743B1
Authority
EP
European Patent Office
Prior art keywords
section
leg portions
cross
tube
tubes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP85901607A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0175743A1 (en
Inventor
Richard Knoll
Edvin List Clausen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Norsk Hydro ASA
Original Assignee
Norsk Hydro ASA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=24360168&utm_source=***_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0175743(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Norsk Hydro ASA filed Critical Norsk Hydro ASA
Priority to AT85901607T priority Critical patent/ATE35049T1/de
Publication of EP0175743A1 publication Critical patent/EP0175743A1/en
Application granted granted Critical
Publication of EP0175743B1 publication Critical patent/EP0175743B1/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D7/06—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits having a single U-bend
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/15—Making tubes of special shape; Making tube fittings
    • B21C37/28—Making tube fittings for connecting pipes, e.g. U-pieces
    • B21C37/283—Making U-pieces

Definitions

  • the present invention relates to a method of manufacturing metallic tubes having two parallel leg portions of oval cross-section, which are connected together by a U-shaped bent portion integrally formed with said tube.
  • This invention relates more particularly to a method of manufacturing metallic hairpin tubes provided with secondary heat exchanger elements or fins fixed to the tubes normally by brazing/soldering, crimping, expansion or gluing.
  • the FR-A-1 086 881 discloses a process of altering tubes with circular cross-section into tubes with an oval cross-section before bending. But there, the problems related to bending flat oval, especially thin-walled metallic tubes, namely a reduction of the cross-section area of the bends and formation of wrinkles on the inner tube walls are not overcome. Both phenomena have an adverse effect on the flow pattern of the circulating fluidum-increase of pressure drop in the heat exchanging systems and erosion of the bent tube parts.
  • the object of the present invention is accomplished by providing a tubular member of substantially circular cross-section, bending said tubular member to a U-shaped hairpin tube including two parallel leg portions, exposing the leg portions to a radial deformation resulting in an oblong cross-section of the entire length or parts of the leg portions.
  • the present invention proposes to bend a circular tube and then to deform only the leg portions to an oblong cross-section. This oval configuration is advantageous with relation to the direction of flow of the exterior heat exchange fluid providing an increased heat exchanger surface.
  • the bent portion has a circular cross-section resulting in an improved heat exchanging efficiency at a minimal pressure drop.
  • the largest diameter of the leg portions always is substantially coplanar with the main stream of the outer heat exchanging medium regardless connection pattern of the tubes applied in a heat exchanger core.
  • the new one-piece hairpin tube (1) provided according to the present invention comprises two parallel leg portions (2,2') of the oblong cross-section connected together by an U-shaped bend portion (3) having a substantially circular cross-section - see Fig. 2.
  • the new and unique configuration of the hairpin tubes is thus provided based upon a new inventive approach to solve the problem connected to bending thin-walled oblong tubes.
  • a typical A1-tube to be used in a motor vehicle radiator or heater core will have a wall thickness of 0.4 mm, central tube distance 22.0 mm and largest diameter of the oblong cross-section 13.0 mm (short diameter 6.0 mm)
  • the tubes are subjected to a bending operation while retaining a substantially circular cross-section over the deformed part of the tubes.
  • a circular tube with a diameter of 10 mm is provided and then by means of commercially available apparatuses, e.g. hydraulically powered tube benders, a bend of 180° is formed as the first step in the manufacture of oblong hairpin tubes.
  • Figs. 4 and 5 show schematically the subsequent step of radial deformation of the just provided hairpin tube from the circular cross-section to an oblong/elliptical cross-section along the parallel leg portions of the tube.
  • the hairpin tube of circular cross-section (1) is inserted between the open jaws (51, 52) of a pressure die (5) so that a predetermined part or the whole leg portions (2, 2') of the hairpin tube being conformed to an oblong cross-section having diameters of 13.0 and 5.7 mm respectively, see Fig. 5, showing a sectional view of the pressure die from Fig. 4 after performance of the deformation step.
  • the hairpin tube provided in the above example exhibits no surface irregularities in the U-bend portion (3) and transition curves of intermediate portions of the tube between the oblong parts and the circular U-bend being smooth without sharp edges. Furthermore, the circular cross-section of the U-bend portion is larger than the cross-section of the leg portions so that the result is a hairpin tube of substantially oblong cross-section body ensuring improved heat exchanging efficiency at a minimal pressure drop in the heat exchanger.
  • Fig. 6 illustrates in planar view the hairpin tube in the pressure die (5) comprising an U-bend portion (3) of the substantially circular cross-section outside the pressure die and the leg portions (2, 2') of the oblong cross-section having free ends (21, 21') retaining the original, circular cross-section.
  • This configuration of the hairpin tube offers a special advantage allowing direct connection to a terminating plate of headers provided with circular apertures.
  • Figs. 3, 9 and 10 represent the most usual patterns of the hairpin tube configuration with regard to the assembling of the heat exchanger cores - so-called parallel, staggered parallel or series connection, respectively.
  • FIG. 7 An alternative manufacturing method to the one described with reference to the above example is illustrated in Figs. 7 and 8.
  • a tube (11) of the required oblong cross-section and dimensions is provided by extrusion, extrusion followed by a drawing operation or by welding.
  • the thus provided tube (11) is then subjected to a local radial deformation over a predeterminated part (3') of the tube.
  • the cross-section of this part (3') being conformed to a circular shape in a pressure die (5) - see Fig. 8 showing the die (5) in a vertical sectional view taken along line I-I of Fig. 7, facilitates the subsequent bending operation conducted by means of adapted commercial benders.
  • the bending operation in this case is a final step in the manufacture of oblong hairpin configurated tubes.
  • the cross-section of the U-bend parts (3) can also exhibit other shapes deviating from the circular one shown in the drawings without departing from the scope of the present invention. Even if the circular cross-section offers advantages such as direct use of commercially available benders without any need for adaptation of the apparatuses or special accessories (mandrels), tubes with other cross- sectional shapes in the bending area can be used. It is, however, important that such cross- sectional shapes comply with the requirements to a cross-section of the U-bend being larger than or equal to a cross-section of the leg portions, and furthermore that the relation between the wall thickness, the bend radius and the largest diameter of the tube according to the above empiric formula ensures avoidance of surface defects on the tube wall.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
EP85901607A 1984-03-14 1985-03-12 Method of manufacturing hairpin configured tubes Expired EP0175743B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85901607T ATE35049T1 (de) 1984-03-14 1985-03-12 Verfahren zur herstellung haarnadelfoermiger rohre.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US58993284A 1984-03-14 1984-03-14
US589932 2000-06-07

Publications (2)

Publication Number Publication Date
EP0175743A1 EP0175743A1 (en) 1986-04-02
EP0175743B1 true EP0175743B1 (en) 1988-06-08

Family

ID=24360168

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85901607A Expired EP0175743B1 (en) 1984-03-14 1985-03-12 Method of manufacturing hairpin configured tubes

Country Status (5)

Country Link
EP (1) EP0175743B1 (ja)
JP (2) JPS61501467A (ja)
BR (1) BR8505815A (ja)
DE (1) DE3563263D1 (ja)
WO (1) WO1985004242A1 (ja)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2023643B3 (es) * 1986-04-04 1992-02-01 Norsk Hydro As Metodo de produccion de junturas soldadas sin fluido e intercambiadores de calor proporcionados por dicho metodo
IT1234289B (it) * 1989-06-14 1992-05-14 Piemontese Radiatori Perfezionamenti apportati ad uno scambiatore di calore a tubi appiattiti
DE102009047620C5 (de) * 2009-12-08 2023-01-19 Hanon Systems Wärmeübertrager mit Rohrbündel
CN106802098B (zh) * 2017-03-10 2024-01-12 东方电气集团东方锅炉股份有限公司 发夹式换热器及其装配方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2952736A1 (de) * 1979-12-29 1981-07-02 Süddeutsche Kühlerfabrik Julius Fr. Behr GmbH & Co KG, 7000 Stuttgart Waermetauscher, insbesondere zwei-oder mehrflutiger kondensator fuer klimaanlagen in kraftfahrzeugen

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1479279A (en) * 1922-09-15 1924-01-01 Superheater Co Ltd Method of making return bends
FR733037A (fr) * 1931-05-07 1932-09-29 Etablissements Krauss Soc D Petit compas pour l'aviation
DE816688C (de) * 1950-02-07 1951-10-11 Rudolf Dipl-Ing Hingst Verfahren zur Herstellung von an den Enden unrunden, im Querschnitt abgesetzten Rohrschenkeln an U-foermigen Umkehrenden, die zwei solcher an den anstossenden Flaechen miteinander verschweissten Rohr-schenkel aufweisen und durch eine angeschweisste Kappeverschlossen sind
FR1086881A (fr) * 1953-07-17 1955-02-16 Procédé de cintrage de tube à paroi mince
US2724891A (en) * 1953-11-10 1955-11-29 Combustion Eng Method of decreasing radius of curvature in return bend
DE2231371C2 (de) * 1972-06-27 1981-10-08 Kabel- und Metallwerke Gutehoffnungshütte AG, 3000 Hannover Vorrichtung zur Herstellung eines elliptischen, gewellten Hohlleiters
JPS5947233B2 (ja) * 1975-06-27 1984-11-17 ニホンラヂエ−タ− カブシキガイシヤ Ｕベント部を有する扁平管を使用した熱交換器
JPS604479B2 (ja) * 1976-08-25 1985-02-04 日本コロムビア株式会社 電磁ピツクアツプ装置
FR2462214A1 (fr) * 1979-07-26 1981-02-13 Ferodo Sa Procede de conformation d'un tube, en particulier pour echangeur de chaleur
FR2462215A1 (fr) * 1979-07-26 1981-02-13 Ferodo Sa Procede de conformation d'un tube en particulier pour echangeur de chaleur et echangeur de chaleur muni de tubes ainsi conformes
JPS58181440A (ja) * 1982-04-19 1983-10-24 Hitachi Ltd 熱交換器

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2952736A1 (de) * 1979-12-29 1981-07-02 Süddeutsche Kühlerfabrik Julius Fr. Behr GmbH & Co KG, 7000 Stuttgart Waermetauscher, insbesondere zwei-oder mehrflutiger kondensator fuer klimaanlagen in kraftfahrzeugen

Also Published As

Publication number Publication date
DE3563263D1 (en) 1988-07-14
EP0175743A1 (en) 1986-04-02
JPH0684173U (ja) 1994-12-02
WO1985004242A1 (en) 1985-09-26
JPS61501467A (ja) 1986-07-17
BR8505815A (pt) 1986-03-25

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