WO1985004242A1 - Hairpin configured tubes and method of manufacture - Google Patents

Hairpin configured tubes and method of manufacture Download PDF

Info

Publication number
WO1985004242A1
WO1985004242A1 PCT/NO1985/000015 NO8500015W WO8504242A1 WO 1985004242 A1 WO1985004242 A1 WO 1985004242A1 NO 8500015 W NO8500015 W NO 8500015W WO 8504242 A1 WO8504242 A1 WO 8504242A1
Authority
WO
WIPO (PCT)
Prior art keywords
section
leg portions
tube
cross
hairpin
Prior art date
Application number
PCT/NO1985/000015
Other languages
French (fr)
Inventor
Richard Knoll
Edvin List Clausen
Original Assignee
Norsk Hydro A.S.
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=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=WO1985004242(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Norsk Hydro A.S. filed Critical Norsk Hydro A.S.
Priority to DE1985901607 priority Critical patent/DE175743T1/en
Priority to BR8505815A priority patent/BR8505815A/en
Priority to AT85901607T priority patent/ATE35049T1/en
Priority to DE8585901607T priority patent/DE3563263D1/en
Publication of WO1985004242A1 publication Critical patent/WO1985004242A1/en

Links

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 tubular members, par ⁇ ticularly tubes forming a continuous path for the circulation of a heat exchanging fluid in heat exchangers, and methods for manufacture of such tubes.
  • This invention relates more particularly to metallic hairpin tubes provided with secondary heat exchanger elements or fins fixed to the tubes normally by brazing/soldering, crimping, expansion or gluing.
  • tubes commonly used in heat exchangers with this type of connection have a circular cross-section which facilitates the assembly of the tube ends, e.g. with U-shaped bends, as disclosed in DE 2952736.
  • Another object of the invention is to provide tubes for heat exchanger units resulting in better heat rejection perform ⁇ ance, reduced number of tube joints and to avoid or facili ⁇ tate connections between tubes of different cross-sectional shape in heat exchangers.
  • Still another object of the invention is to provide a simple and low cost method of manufacturing oblong hairpin tubes.
  • a one-piece hairpin configured tube comprising two sub ⁇ stantially parallel leg portions of oblong cross-section connected by an U-shaped bend portion having a cross-section area larger than or equal to the cross-section of the leg portions.
  • thermoly conductive tubes including hairpin configured U-shaped bends, comprising the steps of providing a (straight) tubular member of substantially circular cross-section, bending the said tubular member providing an U-shaped hairpin tube with two parallel leg por ⁇ tions which are subsequently exposed to a radial deformation operation resulting in an oblong cross-section of the entire length or parts of the leg portions.
  • Fig. 1 is a plan view of a hairpin configured tube.
  • Fig. 2 is a sectional view of the hairpin tube taken along line I-I of Fig. 1.
  • Fig. 3 is another sectional view taken on line " II-II of Fig. 1.
  • Fig. 4 is a sectional view of a tool for accomplishing the step of radial deformation according to the present invention.
  • Fig. 5 is a sectional view of the tool from Fig. 4 after performance of the deformation step.
  • Fig. 6 is a planar view of the hairpin tube in a die after accomplished deformation step.
  • Fig. 7 illustrates the step of conforming of a pre- deter inated part of an oblong tube to a circular cross-section in a modified method of manufacturing the hairpin tubes.
  • Fig. 8 is a sectional view of a tool for accomplishing the conforming operation taken on line I-I of Fig. 7.
  • Figs. 9 and 10 represent modifications in the manner of configuration of the leg portions of the hairpin tubes with regard to the U-bend portion.
  • 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.
  • Dm largest diameter of the tube
  • c central distance between the leg portions
  • d wall-thickness should be ⁇ 10 to ensure smooth quality tubes, at f in a range from 11-14 problems can arise and at f > 14 the problems with formation of wrinkles are unavoidable.
  • a typical Al-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 com ⁇ flashally 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 sec ⁇ tional 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 sub ⁇ stantially 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 portion ' s (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 terminat ⁇ ing 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 and 8 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 pre- determinated part (3 1 ) 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 sec ⁇ tional 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 in ⁇ vention. 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 acces ⁇ sories (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)

Abstract

An integrally formed hairpin configured metallic tube, comprising two parallel leg portions (2, 2') of oblong cross-section connected together by an U-shaped bend portion (3) of substantially circular cross-section. A method of manufacturing hairpin tubes includes the steps of providing a tubular member with a substantially circular cross-section, bending said tubular member to an U-shaped hairpin tube with two parallel leg portions, and subsequent radial deformation of the leg portions to an oblong cross-section.

Description

Hairpin configured tubes and method of manufacture
Field of the invention
The present invention relates to tubular members, par¬ ticularly tubes forming a continuous path for the circulation of a heat exchanging fluid in heat exchangers, and methods for manufacture of such tubes.
This invention relates more particularly to metallic hairpin tubes provided with secondary heat exchanger elements or fins fixed to the tubes normally by brazing/soldering, crimping, expansion or gluing.
Background of the invention
The large number of connections between the tubes of a heat exchanger core and the terminating end plates of fluid tanks (headers) and/or U-shaped bends represent the main manufac¬ turing and operating problems for these heat exchangers. The mechanical strength of the soldered or brazed connections between the tubes and the end plates is poor. These con¬ nections are vulnerable to damages causing leaks as a result of mechanical vibra'tions and due to changes in pressure and temperature to which these parts are subjected. The tube end plate connections, realized by means of re¬ silient joints where the tubes are expanded into a direct, tight engagement with the end plates, are known from prior art. This expansion operation is not an easy task in mass production manufacturing and therefore tubes commonly used in heat exchangers with this type of connection have a circular cross-section which facilitates the assembly of the tube ends, e.g. with U-shaped bends, as disclosed in DE 2952736.
Use of tubes with oblong or flat oval cross-section in order to improve the heat exchanging efficiency (performance) by increasing their surface area without increasing the aero¬ dynamic resistance and/or size of the heat exchangers, is also known. The drawback of the heat exchangers provided with oval tubes is the necessity to conform the ends of the oval tubes to a circular cross-section of the connecting U-shaped bends or openings in the end plates. The conformation of the .tube ends is an additional "operation in assembling of the heat exchangers, which requires narrow dimensional tolerances in order to achieve satisfactorily tight connection between the tubes and the apertures in the perforated end plates. UK patent applications Nos. GB 2.055.064 and GB 2.056.330 disclose one of the known methods of conforming the end"of an oblong metallic tube to a circular cross-section.
Attempts have also been made to provide one-piece hairpin tubes of oval cross-section. Nobody has hitherto succeeded to overcome 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. Both phenomena have an adverse effect on the flow pattern of the circulating fluidum - in¬ crease of pressure drop in the heat exchanging systems and erosion of the bent tube parts. Object of the invention
It is therefore an object of the present invention to provide one-piece hairpin .tube having a body of substantially parallel leg portions with oblong cross-section avoiding the above stated drawbacks connected to the bending operation, and methods for manufacture of such tubes.
Another object of the invention is to provide tubes for heat exchanger units resulting in better heat rejection perform¬ ance, reduced number of tube joints and to avoid or facili¬ tate connections between tubes of different cross-sectional shape in heat exchangers.
Still another object of the invention is to provide a simple and low cost method of manufacturing oblong hairpin tubes.
These and other objects of the pre.sent invention will become apparent upon reading the following specification with accompanying drawings and patent claims.
Summary of the invention
According to the present invention there is provided a one-piece hairpin configured tube comprising two sub¬ stantially parallel leg portions of oblong cross-section connected by an U-shaped bend portion having a cross-section area larger than or equal to the cross-section of the leg portions.
According to the present invention there is also provided a method of manufacture of thermally conductive tubes including hairpin configured U-shaped bends, comprising the steps of providing a (straight) tubular member of substantially circular cross-section, bending the said tubular member providing an U-shaped hairpin tube with two parallel leg por¬ tions which are subsequently exposed to a radial deformation operation resulting in an oblong cross-section of the entire length or parts of the leg portions.
According to the present invention there is still another method of manufacture of hairpin configured tubes comprising the steps of providing a tubular member of oblong cross- section, local conformation of a predetermined part of the tubular member to a substantially circular cross-section and the consequent bending of the said conformed part providing an U-shaped tube with two parallel leg portions of oblong cross-section.
Description of the drawings
Embodiments of the invention are shown by way of non- restrictive examples in the accompanying drawings, Fig. 1 - 10, where
Fig. 1 is a plan view of a hairpin configured tube.
Fig. 2 is a sectional view of the hairpin tube taken along line I-I of Fig. 1.
Fig. 3 is another sectional view taken on line "II-II of Fig. 1.
Fig. 4 is a sectional view of a tool for accomplishing the step of radial deformation according to the present invention.
Fig. 5 is a sectional view of the tool from Fig. 4 after performance of the deformation step. Fig. 6 is a planar view of the hairpin tube in a die after accomplished deformation step.
Fig. 7 illustrates the step of conforming of a pre- deter inated part of an oblong tube to a circular cross-section in a modified method of manufacturing the hairpin tubes.
Fig. 8 is a sectional view of a tool for accomplishing the conforming operation taken on line I-I of Fig. 7.
Figs. 9 and 10 represent modifications in the manner of configuration of the leg portions of the hairpin tubes with regard to the U-bend portion.
Referring to Figs. 1-3, it has been .established that it is possible to obtain a hairpin configured tube (1) retaining the body of the oblong cross-section and to accomplish a bending operation without encountering the above mentioned difficulties/drawbacks known from the prior art. 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.
It has been empirically established that a certain relation between the wall thickness, the central distance of the leg portions (bend-radius) and the largest diameter of the oblong tubes must be respected in order to avoid surface defects on the tube walls during the bending operation. An empirically derived factor f = , where
Dm = largest diameter of the tube, c = central distance between the leg portions and d = wall-thickness should be < 10 to ensure smooth quality tubes, at f in a range from 11-14 problems can arise and at f > 14 the problems with formation of wrinkles are unavoidable.
Example
A typical Al-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 empiric factor in this case is: f = = 19.2 so that the bending operation of such tubes in order to achieve the above central distance between the leg portions of the hairpin tube cannot be conducted without adverse effects on the U-bend surface quality.
According to the present, invention the tubes are subjected to a bending operation while retaining a substantially circular cross-section over the deformed part of the tubes. In a pre¬ ferred embodiment of the invention a circular tube with a diameter of 10 mm is provided and then by means of com¬ mercially 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 sec¬ tional 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 sub¬ stantially 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 portion's (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 terminat¬ ing plate of headers provided with circular apertures.
Other types of conforming apparatus than the pressure die shown and described in connection with the above example can be used for the conforming operations, e.g. drawing dies. The apparent advantage of the described pressure form ing opera¬ tion is that it ensures by simple means a. controlled fixation of the desired angle between the leg portions (2,2') and the U-bend (3) of the hairpin tubes. 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.
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 pre- determinated part (31) 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 sec¬ tional 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 in¬ vention. 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 acces¬ sories (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.

Claims

Cla ims
1. A hairpin configured metallic tube, particularly for thermally conductive tubing in heat exchangers, com¬ prising two parallel leg portions (2,2' ) of oblong cross-section connected together by an U-shaped bend portion (3) having a cross-section area larger than or equal to the cross-section of the leg portions, and integrally formed of a tube of non-ferrous metal.
2. Tube according to claim 1, where the bend portion (3) has a substantially circular cross-section
3. Tube according to claim 2, where free ends (22,2*2') of the parallel leg portions (2,2') have a circular cross-section.
4. A method of manufacturing metallic tubes according to claim 1, comprising the steps of providing a tubular member of substantially circular cross-section, bending said tubular member to an 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.
5. The method according to claim 4, where the radial deformation of said leg portions is carried out as a pressure forming operation in a die.
6. A method of manufacturing metallic tubes according to claim 1, comprising the steps of providing a tubular member of oblong cross-section, local conformation of a predetermined part of the tubular member to a substantially circular cross- section, bending said tubular member over the conformed part providing an U-shaped hairpin tube with two parallel leg portions of oblong cross-section.
PCT/NO1985/000015 1984-03-14 1985-03-12 Hairpin configured tubes and method of manufacture WO1985004242A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE1985901607 DE175743T1 (en) 1984-03-14 1985-03-12 HAIRPIN SHAPED TUBES AND METHOD FOR THEIR PRODUCTION.
BR8505815A BR8505815A (en) 1984-03-14 1985-03-12 TUBES IN THE HAIR CLAMP CONFIGURATION AND THE PROCESS OF ITS MANUFACTURING
AT85901607T ATE35049T1 (en) 1984-03-14 1985-03-12 PROCESS FOR MAKING HAIRPIN-SHAPED TUBE.
DE8585901607T DE3563263D1 (en) 1984-03-14 1985-03-12 Method of manufacturing hairpin configured tubes

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US58993284A 1984-03-14 1984-03-14
US589,932 1984-03-14

Publications (1)

Publication Number Publication Date
WO1985004242A1 true WO1985004242A1 (en) 1985-09-26

Family

ID=24360168

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO1985/000015 WO1985004242A1 (en) 1984-03-14 1985-03-12 Hairpin configured tubes and method of manufacture

Country Status (5)

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

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3936109A1 (en) * 1989-06-14 1990-12-20 Piemontese Radiatori Motor vehicle radiator core - is constructed from flattened tubes bent to U=shape

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3772082D1 (en) * 1986-04-04 1991-09-19 Norsk Hydro As METHOD FOR PRODUCING FLUX-FREE SOLDERED CONNECTIONS AND HEAT EXCHANGERS PRODUCED BY THIS METHOD.
DE102009047620C5 (en) * 2009-12-08 2023-01-19 Hanon Systems Heat exchanger with tube bundle
CN106802098B (en) * 2017-03-10 2024-01-12 东方电气集团东方锅炉股份有限公司 Hairpin heat exchanger and method of assembling the same

Citations (8)

* 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 (en) * 1931-05-07 1932-09-29 Etablissements Krauss Soc D Small compass for aviation
DE816688C (en) * 1950-02-07 1951-10-11 Rudolf Dipl-Ing Hingst Process for the production of tube legs which are non-circular at the ends and have a stepped cross-section on U-shaped reversal ends, which have two such tube legs welded to one another on the abutting surfaces and which are closed by a welded cap
FR1086881A (en) * 1953-07-17 1955-02-16 Thin Wall Tube Bending Process
US2724891A (en) * 1953-11-10 1955-11-29 Combustion Eng Method of decreasing radius of curvature in return bend
DE2231371A1 (en) * 1972-06-27 1974-01-10 Kabel Metallwerke Ghh METHOD OF MANUFACTURING AN ELLIPTICAL CORRUGATED HOLLOW CONDUCTOR
GB2055064A (en) * 1979-07-26 1981-02-25 Valeo A method for the conformation of a metallic tube, particularly for a heat exchanger
GB2056330A (en) * 1979-07-26 1981-03-18 Valeo Method for changing the shape of a tube end particularly for a heat exchanger and a heat exchanger provided with tubes thus changed

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5947233B2 (en) * 1975-06-27 1984-11-17 ニホンラヂエ−タ− カブシキガイシヤ Heat exchanger using flat tubes with U vents
JPS604479B2 (en) * 1976-08-25 1985-02-04 日本コロムビア株式会社 electromagnetic pick-up device
DE2952736A1 (en) * 1979-12-29 1981-07-02 Süddeutsche Kühlerfabrik Julius Fr. Behr GmbH & Co KG, 7000 Stuttgart HEAT EXCHANGER, ESPECIALLY TWO OR MULTIPLE FLOW CAPACITOR FOR AIR CONDITIONING IN MOTOR VEHICLES
JPS58181440A (en) * 1982-04-19 1983-10-24 Hitachi Ltd Heat exchanger

Patent Citations (8)

* 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 (en) * 1931-05-07 1932-09-29 Etablissements Krauss Soc D Small compass for aviation
DE816688C (en) * 1950-02-07 1951-10-11 Rudolf Dipl-Ing Hingst Process for the production of tube legs which are non-circular at the ends and have a stepped cross-section on U-shaped reversal ends, which have two such tube legs welded to one another on the abutting surfaces and which are closed by a welded cap
FR1086881A (en) * 1953-07-17 1955-02-16 Thin Wall Tube Bending Process
US2724891A (en) * 1953-11-10 1955-11-29 Combustion Eng Method of decreasing radius of curvature in return bend
DE2231371A1 (en) * 1972-06-27 1974-01-10 Kabel Metallwerke Ghh METHOD OF MANUFACTURING AN ELLIPTICAL CORRUGATED HOLLOW CONDUCTOR
GB2055064A (en) * 1979-07-26 1981-02-25 Valeo A method for the conformation of a metallic tube, particularly for a heat exchanger
GB2056330A (en) * 1979-07-26 1981-03-18 Valeo Method for changing the shape of a tube end particularly for a heat exchanger and a heat exchanger provided with tubes thus changed

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3936109A1 (en) * 1989-06-14 1990-12-20 Piemontese Radiatori Motor vehicle radiator core - is constructed from flattened tubes bent to U=shape

Also Published As

Publication number Publication date
BR8505815A (en) 1986-03-25
JPH0684173U (en) 1994-12-02
EP0175743B1 (en) 1988-06-08
JPS61501467A (en) 1986-07-17
EP0175743A1 (en) 1986-04-02
DE3563263D1 (en) 1988-07-14

Similar Documents

Publication Publication Date Title
EP0597801B1 (en) Heat exchanger and manufacturing method
US5579837A (en) Heat exchanger tube and method of making the same
JP4050910B2 (en) Heat exchanger
US6061904A (en) Heat exchanger and method for manufacturing the same
JP7243104B2 (en) Heat exchanger and manufacturing method thereof
JP2977824B2 (en) Double-row heat exchanger and method of manufacturing the same
EP1030753B1 (en) Method for assembling a heat exchanger
JPH05172488A (en) Partition plate assembling structure of header pipe for heat exchanger and assembling method therefor
US5404942A (en) Heat exchanger and method of making the same
US5092397A (en) Fin for a heat exchanger and heat exchanging system using the fin
JPH07218170A (en) Tubular section for heat exchanger, molding equipment thereof and heat exchanger thereof
KR20150053135A (en) Heat exchanger and Manufacturing method fo the same
US5890288A (en) Method for making a heat exchanger tube
US5934365A (en) Heat exchanger
WO1985004242A1 (en) Hairpin configured tubes and method of manufacture
US3452814A (en) Bell-end condenser tubes
CN210570100U (en) Heat exchanger
JP2014105951A (en) Heat exchanger
KR102343097B1 (en) Tube for heat exchanger, manufacturing method of the same, and heat exchanger
JP2019126830A (en) Metal round pipe, heat exchanger comprising the same, pipe bender and method for bending metal round pipe
JP3799671B2 (en) Heat exchanger, heat exchanger tube and heat exchanger manufacturing method
KR100376653B1 (en) Core for heat exchanger
JP3947833B2 (en) Heat exchanger
JP2750167B2 (en) Heat exchanger
EP0668114A1 (en) A tool for making U-shaped bends in heat-exchanger tubes having radial fins projecting from the internal walls of the tubes

Legal Events

Date Code Title Description
AK Designated states

Designated state(s): BR JP KP

AL Designated countries for regional patents

Designated state(s): AT BE CH DE FR GB LU NL SE

WR Later publication of a revised version of an international search report
WWE Wipo information: entry into national phase

Ref document number: 1985901607

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1985901607

Country of ref document: EP

WWG Wipo information: grant in national office

Ref document number: 1985901607

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1985901607

Country of ref document: EP