US3744290A - Production of intermittently fluted tubes - Google Patents

Production of intermittently fluted tubes Download PDF

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Publication number
US3744290A
US3744290A US00190148A US3744290DA US3744290A US 3744290 A US3744290 A US 3744290A US 00190148 A US00190148 A US 00190148A US 3744290D A US3744290D A US 3744290DA US 3744290 A US3744290 A US 3744290A
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United States
Prior art keywords
tube
die
ridges
mandrel
valleys
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Expired - Lifetime
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US00190148A
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English (en)
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B Sirois
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Phelps Dodge Copper Products Corp
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Phelps Dodge Copper Products Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D15/00—Corrugating tubes
    • B21D15/02—Corrugating tubes longitudinally

Definitions

  • ABSTRACT A fluted mandrel is movable axially within the tube which is drawn through a fluting die, the ridges of the fluted mandrel being aligned with the valleys formed by the fluted die.
  • Evaporators for making fresh water from sea water vary in design depending on the distillation process used.
  • Distillation systems known as Long Tube Vertical (LTV) or Falling-Film Multi-Effect (FF-ME) make use of heat exchanger tubes with diameters ranging up to 3 inches.
  • the heat exchange tubes are arranged vertically.
  • tubes with longitudinal flutes on the inner and outer surface double fluted tubes improve the rate of heat transfer over that obtained with smooth round tubes having the same external diameter and wall thickness as the fluted tubes.
  • the external diameter of the smooth portion of the tube ends must be essentially the same as the external diameter of the fluted portion of the tube.
  • Such double fluted or enhanced tubes for heat exchangers normally require relatively thin walls of 0.030 to 0.060 inch. Therefore, it is important in the production of these tubes that the stresses created in them during drawing thereof are carefully limited to avoid rupturing of the tubes.
  • the procedures heretofore proposed for their production are not entirely adequate in this respect. Also, these prior procedures leave much to be desired with respect to efficiency and low cost of production.
  • the principal object of the present invention is to provide a method and apparatus which overcome these deficiencies in the prior art of producing such tubes.
  • the tube is passed through a fluting zone where there is formed in the tube, from outside thereof, a first series of deep longitudinal grooves and corresponding ridges spaced circumferentially around the tube.
  • the tube is formed from inside thereof with a second series of depp longitudinal grooves and corresponding ridges alternating with the grooves and ridges of the first series.
  • the tube is provided with longitudinal flutes on its inner and outer surface as it proceeds through the fluting zone.
  • the formation of grooves and corresponding ridges from inside the tube is discontinued during further passage of the tube through the fluting zone, at which time is impressed from outside thereof with only shallow grooves aligned longitudinally with respective deep grooves of the aforementioned first series.
  • the double fluting of the tube is interrupted by an unfluted length of the tube having an external diameter essentially the same as the external diameter of the fluted portion of the tube, the outer surface of this unfluted length having only slight and unobjectionable draw marks left by the fluting die which contributes to the double fluting operation.
  • An apparatus made according to the invention comprises a fluting die forming a passage through which the tube is movable longitudinally and having a central longitudinal axis.
  • the die has a series of longitudinal ridges spaced around this axis and partly defining the aforementioned passage, there being valleys between adjacent ridges.
  • a mandrel movable along the axis has a series of longitudinal peripheral ridges aligned with respective vallyes in the die, the mandrel ridges forming valleys aligned with respective ridges of the die.
  • Means are provided for moving the mandrel along the axis from a first position within the die, wherein the ridges of the mandrel and die are received in respective aligned valleys but with a clearance sufficient to accommodate movement of the tube through the die passage, to a second position in which the mandrel is withdrawn from the die so that it does not act upon the tube surrounding the mandrel and passing through the die passage.
  • FIG. 1 is a longitudinal sectional view of a preferred form of the new apparatus, showing the tube passing through the fluting die with the mandrel positioned in the tube to effect the double fluting operation;
  • FIG. 2 is a view similar to FIG. 1 but showing the mandrel withdrawn from the die to provide a smooth land interrupting the double fluted portion of the tube;
  • FIG. 3 is an enlarged sectional view on line 3-3 in FIG. 1;
  • FIG. 4 is an enlarged sectional view on line 44 in FIG. 2;
  • FIGS. 5 and 6 are sectional views on lines 5-5 and 6-6, respectively, in FIG. 1;
  • FIG. 7 is a sectional view on line 7-7 in FIG. 2;
  • FIG. 8 is an enlarged end view of the fluting die shown in FIGS. 1 and 2, and
  • FIG. 9 is an end view of the mandrel shown in FIGS 1 and 2.
  • the apparatus there shown comprises a fluting die 10 forming a passage 11 through which the tube T is movable longitudinally, this passage having a central longitudinal axis C.
  • the die 10 has a series of longitudinal ridges 10a spaced-around the axis C and partly defining the passage 11, a valley 10b being formed between each pair of adjacent ridges.
  • a mandrel 12 is movable along the axis C of the die passage and has a series of. longitudinal peripheral ridges 12a aligned with respective valleys 10b in the die. As shown particularly in FIG. 9, the mandrel ridges 12a form valleys 12b, the latter being aligned with respective ridges 10a of the die.
  • the tube T is passed through the fluting die 10 while surrounding the mandrel 12.
  • the mandrel 12 is positioned within the die (FIG. 1) so that the die ridges 10a are received in respective aligned valleys 12b of the mandrel, and the mandrel ridges are received in respective aligned valleys 10b of the die.
  • the ridges are received in their respective valleys with sufficient clearance to accommodate movement of the tube through the die passage 11, this movement occurring from right to left in FIGS. 1 and 2.
  • each die ridge a engages the outer surface of the tube to press it inwardly into an opposing valley 12b of the mandrel, while each mandrel ridge 12a engages the inner surface 7 of the tube to press it outwardly into an opposing valley 10b of the die.
  • the resulting double fluted portion of the tube is indicated at T1 and will extend over the length of the tube which passes through the die while the mandrel 12 is in its FIG. 1 position.
  • the mandrel 12 When the double fluting of the tube is to be interrupted, the mandrel 12 is withdrawn from the die along the central axis C until it assumes the position shown in FIG. 2. In this position, the mandrel is located within the part of the tube which is advancing toward the die 10, and the mandrel ridges 12a are disengaged from the inner surface of the tube. Consequently, although the die ridges 10a continue to engage the outer surface of the tube, this engagement is relatively light so that it merely draws the tube to a somewhat reduced diameter while forming very shallow grooves or draw marks in the outer surface of the tube. These draw marks, indicated at in FIG. 7, are not objectionable. Accordingly, the operation as illustrated in FIG. 2 provides the tubes with an essentially smooth portion T2 extending over the desired length of the tube. By cutting the tube between the ends of its smooth portion T2, the desired smooth lands are provided for rolling and sealing the tubes into a tube-sheet.
  • FIG. 2 The operation illustrated in FIG. 2 is shown in further detail in FIG. 4, from which it will be observed that the tube is engaged only by the die ridges 10a. This rela tively light engagement does not distort the tube but merely indents its outer surface slightly to form the draw marks 20.
  • thin-walled tubes- can be produced which have a smooth cylindrical portion adjacent a double fluted portion in which the flutes are uniformly distributed around the tube periphery.
  • OD nominal outer diameter
  • the fluting operation using matching dies and mandrels may be performed in one or more drawing operations. Normally, the fluting operation is followed by one or more sink draws in which the fluted tube is drawn through smooth unfluted round dies in order to reduce the fluted tube to the desired final external diameter.
  • the following is a typical procedure used in making Copper Alloy No. 687 double fluted tubes:
  • a tube made according to the above-described procedure is not satisfactory if the longitudinal flutes extend over its entire length. That is, in fabricating the heat exchanger, the tube must be rolled into a tubesheet at each end; and rolling of an as-fluted tube into the tube sheets is difficult and, for certain metals, the rolled as-fluted tube ends could fail prematurely when made from alloys susceptible to stress cracking. This is due to the high level of unbalanced residual stresses left in the tube at the end of the tube roll.
  • Fluted tubes are normally required in short lengths, for example, 3 to 20 feet. Production of tubes with smooth ends in short individual lengths on conventional drawbench equipment substantially increases production costs. Lower production costs are achieved through practice of the present invention by forming long fluted tubes with interrupted flutes, where the smooth lands are needed, to make multiples of the designed lengths.
  • a tube-drawing die forming a passage through which a tube is movable longitudinally in one direction and having a central longitudinal axis, said die having integral therewith a series of fixed longitudinal ridges spaced around said axis and partly defining said passage, there being valleys between adjacent ridges, a mandrel movable along said axis and having integral therewith a series of fixed longitudinalperipheral ridges aligned with respective valleys in the die, said mandrel ridges forming valleys aligned with respective ridges of the die, and means for moving said mandrel along said axis in a direction opposite to said one direction and from a first position within the die, wherein said ridges are received in the respective aligned valleys but with a clearance sufficient to accommodate said movement of the tube through said die passage, to a second position wherein said mandrel ridges are withdrawn longitudinally from said valleys in the die.
  • the method which comprises passing a tube lengthwise through a fluting zone while reducing the tube diameter and forming in the tube from a first sub-zone outside thereof a first series of deep longitudinal grooves and corresponding ridges spaced circumferentially around the tube and while forming in the tube from a second sub-zone, located inside the tube and within said first sub-zone, a second series of deep longitudinal grooves and corresponding ridges alternating with said grooves and ridges of the first series, and intermittently discontinuing said formation of said second series of grooves and corresponding ridges by moving said second subzone lengthwise of the tube to retract said second subzone from within the first sub-zone into an unreduced portion of the tube and while impressing in the tube from said first sub-zone, during passage of the tube therethrough, only shallow grooves aligned longitudinally with respective deep grooves of said first series.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Shaping Of Tube Ends By Bending Or Straightening (AREA)
  • Extrusion Of Metal (AREA)
  • Metal Extraction Processes (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
US00190148A 1971-10-18 1971-10-18 Production of intermittently fluted tubes Expired - Lifetime US3744290A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US19014871A 1971-10-18 1971-10-18

Publications (1)

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US3744290A true US3744290A (en) 1973-07-10

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US00190148A Expired - Lifetime US3744290A (en) 1971-10-18 1971-10-18 Production of intermittently fluted tubes

Country Status (7)

Country Link
US (1) US3744290A (enrdf_load_stackoverflow)
JP (1) JPS5146504B2 (enrdf_load_stackoverflow)
DE (1) DE2250850C3 (enrdf_load_stackoverflow)
FR (1) FR2156707A1 (enrdf_load_stackoverflow)
GB (1) GB1369738A (enrdf_load_stackoverflow)
IL (1) IL40302A (enrdf_load_stackoverflow)
IT (1) IT966600B (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4232541A (en) * 1979-01-23 1980-11-11 The Babcock & Wilcox Company Drawing technique
US4313328A (en) * 1979-06-25 1982-02-02 Mannesmann Aktiengesellschaft Providing cardan and universal joint-type shafts with gearing
US4622840A (en) * 1983-06-20 1986-11-18 Neapco, Inc. Method for drawing telescoping tubes for torque transmission
US4838063A (en) * 1984-09-10 1989-06-13 Hitachi Cable, Ltd. Method for manufacturing metallic tube members
EP0295919A3 (en) * 1987-06-19 1989-11-23 The Babcock & Wilcox Company Cold drawing technique and apparatus for forming internally grooved tubes
US5809822A (en) * 1995-01-25 1998-09-22 Butty; Jean-François Method of producing a metallic hollow body with a breaking line
US20040050133A1 (en) * 2000-09-25 2004-03-18 Tsuyoshi Ishikawa Method of forming cold diametrally reducing roll for metal pipe and metal pipe formed by the method
US20110296890A1 (en) * 2008-08-21 2011-12-08 Showa Denko K.K. Device for drawing tubular workpiece
ITTO20120551A1 (it) * 2012-06-22 2013-12-23 Lucio Carretta Procedimento per la fabbricazione di un tubo metallico avente almeno una porzione liscia ed almeno una porzione scanalata, apparecchiatura utilizzata nel procedimento e prodotto ottenuto
US20190203753A1 (en) * 2017-12-28 2019-07-04 Jyen Herr Enterprise Co., Ltd. Connection tube for power tool

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5716224U (enrdf_load_stackoverflow) * 1980-06-09 1982-01-27
DE3807002C1 (enrdf_load_stackoverflow) * 1988-03-01 1989-04-27 Mannesmann Ag, 4000 Duesseldorf, De

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US629245A (en) * 1898-07-21 1899-07-18 Salomon Frank Apparatus for producing ribbed or corrugated tubes.
US1985833A (en) * 1930-12-20 1934-12-25 Berlin Karisruher Ind Werke A Method of making grooved sleeves
US2001643A (en) * 1930-10-03 1935-05-14 American Fork & Hoe Co Method of forming golf shafts and the like
US2258242A (en) * 1940-09-27 1941-10-07 Phelps Dodge Copper Prod Apparatus for drawing tubes of multiple wall thickness
US3008187A (en) * 1959-01-05 1961-11-14 Raybestos Manhattan Inc Method and apparatus for extruding polytetrafluoroethylene tubing
US3068550A (en) * 1960-02-12 1962-12-18 Gen Motors Corp Method and mechanism for forming annular grooves
US3118328A (en) * 1964-01-21 Apparatus for producing longitudinal

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3118328A (en) * 1964-01-21 Apparatus for producing longitudinal
US629245A (en) * 1898-07-21 1899-07-18 Salomon Frank Apparatus for producing ribbed or corrugated tubes.
US2001643A (en) * 1930-10-03 1935-05-14 American Fork & Hoe Co Method of forming golf shafts and the like
US1985833A (en) * 1930-12-20 1934-12-25 Berlin Karisruher Ind Werke A Method of making grooved sleeves
US2258242A (en) * 1940-09-27 1941-10-07 Phelps Dodge Copper Prod Apparatus for drawing tubes of multiple wall thickness
US3008187A (en) * 1959-01-05 1961-11-14 Raybestos Manhattan Inc Method and apparatus for extruding polytetrafluoroethylene tubing
US3068550A (en) * 1960-02-12 1962-12-18 Gen Motors Corp Method and mechanism for forming annular grooves

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4232541A (en) * 1979-01-23 1980-11-11 The Babcock & Wilcox Company Drawing technique
US4313328A (en) * 1979-06-25 1982-02-02 Mannesmann Aktiengesellschaft Providing cardan and universal joint-type shafts with gearing
US4622840A (en) * 1983-06-20 1986-11-18 Neapco, Inc. Method for drawing telescoping tubes for torque transmission
US4838063A (en) * 1984-09-10 1989-06-13 Hitachi Cable, Ltd. Method for manufacturing metallic tube members
EP0295919A3 (en) * 1987-06-19 1989-11-23 The Babcock & Wilcox Company Cold drawing technique and apparatus for forming internally grooved tubes
US5809822A (en) * 1995-01-25 1998-09-22 Butty; Jean-François Method of producing a metallic hollow body with a breaking line
US20070113611A1 (en) * 2000-09-25 2007-05-24 Tsuyoshi Ishikawa Cold roll forming method for reducing a diameter of a metal pipe, and a metal pipe product having its diameter reduced by such method
US20060201223A1 (en) * 2000-09-25 2006-09-14 Tsuyoshi Ishikawa Cold roll forming method for reducing a diameter of a metal pipe, and a metal pipe product having its diameter reduced by such method
US20040050133A1 (en) * 2000-09-25 2004-03-18 Tsuyoshi Ishikawa Method of forming cold diametrally reducing roll for metal pipe and metal pipe formed by the method
US20080148797A1 (en) * 2000-09-25 2008-06-26 Tsuyoshi Ishikawa Cold roll forming method for reducing a diameter of a metal pipe, and a metal pipe product having its diameter reduced by such method
US20090199924A1 (en) * 2000-09-25 2009-08-13 Nakayama Corporation Cold roll forming method for reducing a diameter of a metal pipe, and a metal pipe product having its diameter reduced by such method
US20110296890A1 (en) * 2008-08-21 2011-12-08 Showa Denko K.K. Device for drawing tubular workpiece
US9636727B2 (en) * 2008-08-21 2017-05-02 Showa Denko K.K. Device for drawing tubular workpiece
ITTO20120551A1 (it) * 2012-06-22 2013-12-23 Lucio Carretta Procedimento per la fabbricazione di un tubo metallico avente almeno una porzione liscia ed almeno una porzione scanalata, apparecchiatura utilizzata nel procedimento e prodotto ottenuto
US9573180B2 (en) 2012-06-22 2017-02-21 Lucio Carretta Method and apparatus for fabricating a metal pipe having at least one smooth portion and at least one grooved portion
US20190203753A1 (en) * 2017-12-28 2019-07-04 Jyen Herr Enterprise Co., Ltd. Connection tube for power tool

Also Published As

Publication number Publication date
FR2156707A1 (enrdf_load_stackoverflow) 1973-06-01
DE2250850C3 (de) 1975-03-27
DE2250850A1 (de) 1973-04-26
JPS5146504B2 (enrdf_load_stackoverflow) 1976-12-09
GB1369738A (en) 1974-10-09
JPS4849658A (enrdf_load_stackoverflow) 1973-07-13
IT966600B (it) 1974-02-20
IL40302A (en) 1976-07-30
IL40302A0 (en) 1972-11-28
DE2250850B2 (de) 1974-08-22

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