US2216778A - Heat exchange member and method of making - Google Patents

Heat exchange member and method of making Download PDF

Info

Publication number
US2216778A
US2216778A US155186A US15518637A US2216778A US 2216778 A US2216778 A US 2216778A US 155186 A US155186 A US 155186A US 15518637 A US15518637 A US 15518637A US 2216778 A US2216778 A US 2216778A
Authority
US
United States
Prior art keywords
tube
slots
fins
plates
making
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 - Lifetime
Application number
US155186A
Inventor
Eugene J Houdry
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.)
Houdry Process Corp
Original Assignee
Houdry Process Corp
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
Application filed by Houdry Process Corp filed Critical Houdry Process Corp
Priority to US155186A priority Critical patent/US2216778A/en
Application granted granted Critical
Publication of US2216778A publication Critical patent/US2216778A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21CMANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06Manufacture 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
    • B21C37/15Making tubes of special shape; Making tube fittings
    • B21C37/22Making finned or ribbed tubes by fixing strip or like material to tubes
    • B21C37/24Making finned or ribbed tubes by fixing strip or like material to tubes annularly-ribbed tubes
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28FDETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00Tubular elements; Assemblies of tubular elements
    • F28F1/10Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/24Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
    • F28F1/30Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means being attachable to the element
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/4935Heat exchanger or boiler making
    • Y10T29/49377Tube with heat transfer means
    • Y10T29/49378Finned tube

Definitions

  • the present invention relates to finned tubes or conduits and to a method of making or constructing the same. More particularly the invention concerns the use of fins on tubes or con- 5' duits, as hereinafter illustrated and described, and to a method of assembling the iins on and attaching them to tubes.
  • the fins primarily contemplated may be referredto as transverse fins.
  • a further object is to employ nn members which are of such structure that they are particularly adaptable for use in my method of 145v assembly.
  • One aspect of my invention involves shaping the iins so that portions or flanges thereof provide for uniform or any desired spacing of fins.
  • vIilg. 3 is a longitudinal sectional view taken on 35- line I-I of Fig. 2.
  • Theiins. such as'n 2 shown inFig. l ornns 2a shown in Figs. 2 and 3. may be formed from plates of any desired'thickness cut in desired shapes (e. g., square or round) which are ceno trally punched and then drawn; expanded or otherwise processed to provide a flange (continuous or broken) which will fit the tube to which the tins are to be attached.
  • the plates may be slotted from the periphery -of each to points adja- 45 cent the central opening to produce fins which are generally segmental in character. This may 4 duit, ⁇ nn members of square, round or other desired peripheral contour are forced over or slid o VVonto'me.rimessa positioned with the slots in the several fins in straight or curved alignment.
  • a plurality of rows of slots 3a may be provided, four rows being indicated.
  • the ns may be held in desired spaced relation by flanges, such as upturned 5 ange Il on iin member 2 or flanges la shown in Figs. 2 and ⁇ 3, or they may be spacedby collars of suitable length which surround the tube and are disconnected from' the fin members.
  • flanges such as upturned 5 ange Il on iin member 2 or flanges la shown in Figs. 2 and ⁇ 3, or they may be spacedby collars of suitable length which surround the tube and are disconnected from' the fin members.
  • -Notches or the like may be provided on successiveiins, if lo desired, to insure the maintenance .of proper alignment of slots sa during welding, although this is generally unnecessary.
  • Welding electrode 8 (Fig.
  • the plates or iins are preferably slotted deeply enough so that tno nn mem wm be nuxeo with 3 the metal of the tube during the welding operation.
  • the ilange I of the n n is suiliciently thin no slottm'g at ou ormenange wnlbenes-- sary in order to weld the ange to the tube but, when it is thicker, the aange my be partially slotted, as illustrated in-Fig. 1 by the partial slots 4 which beginwhere the full slots I end.
  • the radial slots may be cut entirely through the plate, including the flange, in whichcase the sections of the plates or ons wm be held in place 0 by a press or other suitable means while being welded to the tube. 'Howeven when cutting the radial slots (such as slots l in Fig. l or la in Fig.
  • the flange on each plate when employed, provides a m good bearing surface on the tube and maygripv the same with alight press fit, tack or'spot welding of flanges is suiilcient formany uses.
  • the flanges may be used only as spacer members, not welded to the tube, conduction between the tube and iin being established by welding the iln to the tube at the inner ends of the slots, such as of slots 3 and 3a shown in the drawing.
  • the fianges of the ilns may be welded to the tube at points intermediate the slots by making a step rotation oi' either the welding head or the tube assembly as the welding head advances in relation to the tube.
  • the step rotation may, for example, be of 30, 45 or 60 degrees, more or less.
  • nned tubes as described are many and varied. They may be used where there is a fluid inside the tube and a solid material surrounding the tube, or vice versa, or where there are iluids both within and around the tube, or where there are solids both within and around the tube, where it is desired to eect the exchange of heat between points within the tube and points exterior thereto.
  • finned tubes or conduits constructedas herein illustrated may be employed in controlling the temperatures of catalytic beds or masses, e. g., in apparatus such as shown in Patent. No. 2,078,947, issued to myself on May 4, 1937 or in my copending application VSerial No.
  • the tubes or conduits on which the fins are attached obviously are not limited to single-walled tubes but include other types of conduits, e. g., double or nested conduit assemblies such as shown in Patent No. 1,987,903, issued to myself on Januaryl, 1935, or conduits of the type illustrated in my ⁇ aforementioned Patent No. 2,078,947 or my aforementioned copending application.
  • steps o1' forming ilanged apertures in metal plates, providing slots in each plate from the periphery to points adjacent the aperture and grooves' in the outer wall of each flange in line with the slots, positioning the plates on the tubethrough the apertures and spacing the plates by means of the aperture flanges, aligning the slots of each plate and Joining the plates to 'the tube by fusing the grooved areas of the flanges to the tube.
  • a finned heat exchange device adapted f emcient heat transfer comprising a conduit for conveying fluid, apertured plates extending transversely of the conduit, each plate having the apertures provided with spacing flanges and slots outwardly thereof. said slots extending from the outer edge of the plate to said flange forming segments of extensive heat exchange surface, and a welded joint between the segments for securing each plate integrally to the conduit with the slots in alignment.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Geometry (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Description

Oct. 8, 1940- E. .1, HoUDRY HEAT EXCHANGE MEMBER AND METHOD OF MAKING Filed July 23, 1937 mvENToR E ugeNE LHD udrg ATTORNEY roten-ted oct. s, 1940 lUNITED STATES PATENT oFFicE 'HEAT EXCHANGE RIEMBER AND METHOD F MAKING Application July 23, 1937, Serial No. 155,186
Claims.
'I'he present invention relates to finned tubes or conduits and to a method of making or constructing the same. More particularly the invention concerns the use of fins on tubes or con- 5' duits, as hereinafter illustrated and described, and to a method of assembling the iins on and attaching them to tubes. The fins primarily contemplated may be referredto as transverse fins.
It is an object of this invention to provide a y method for rapidly making or fabricating conduits with transverse or similar ns attached thereto. A further object is to employ nn members which are of such structure that they are particularly adaptable for use in my method of 145v assembly. -One aspect of my invention involves shaping the iins so that portions or flanges thereof provide for uniform or any desired spacing of fins. These and other objects and advantages will be' apparent from the description taken as a The problem of making tubes having transverse fins attached thereto, and doing so rapidly and cheaply, is one of considerable commercial 2 is a perspective view of -a tube or conduit having a series ot fins of different shape thereon and in the course of being attached thereto; and
vIilg. 3 is a longitudinal sectional view taken on 35- line I-I of Fig. 2.
Theiins. such as'n 2 shown inFig. l ornns 2a shown in Figs. 2 and 3. may be formed from plates of any desired'thickness cut in desired shapes (e. g., square or round) which are ceno trally punched and then drawn; expanded or otherwise processed to provide a flange (continuous or broken) which will fit the tube to which the tins are to be attached. The plates may be slotted from the periphery -of each to points adja- 45 cent the central opening to produce fins which are generally segmental in character. This may 4 duit,` nn members of square, round or other desired peripheral contour are forced over or slid o VVonto'me.rimessa positioned with the slots in the several fins in straight or curved alignment.
5s (In the event that the ilns are slotted after being mounted on the tube, the slots will be made in alignment.) As illustrated in Fig. 2 I a plurality of rows of slots 3amay be provided, four rows being indicated. The ns may be held in desired spaced relation by flanges, such as upturned 5 ange Il on iin member 2 or flanges la shown in Figs. 2 and `3, or they may be spacedby collars of suitable length which surround the tube and are disconnected from' the fin members. -Notches or the like may be provided on successiveiins, if lo desired, to insure the maintenance .of proper alignment of slots sa during welding, although this is generally unnecessary. Welding electrode 8 (Fig. 2), shown in broken away view, is in the "course of being moved lengthwise of the t`ube through one row of slots, thus simply and quickly to weld the iins 2a to the tube I; note the welding bead 1. In place of the welding, electrode shown. any other desired type of welding tool may be employed. It is optional whether the welding head is maintained stationary land the tube is moved therealong so that the welding tool passes through the aligned slots,- or vice versa, whether the tube is maintained stationary and the welding tool is moved. Also. welding tools may be passed through any plurality or all of slots simultaneously, if desired. and this'is sometimes advantageous in the production of a finished tlnned tube which is free from warpage.
The plates or iins are preferably slotted deeply enough so that tno nn mem wm be nuxeo with 3 the metal of the tube during the welding operation. Where the ilange I of the n n is suiliciently thin no slottm'g at ou ormenange wnlbenes-- sary in order to weld the ange to the tube but, when it is thicker, the aange my be partially slotted, as illustrated in-Fig. 1 by the partial slots 4 which beginwhere the full slots I end. The radial slots may be cut entirely through the plate, including the flange, in whichcase the sections of the plates or ons wm be held in place 0 by a press or other suitable means while being welded to the tube. 'Howeven when cutting the radial slots (such as slots l in Fig. l or la in Fig.
2), it is preferable to make the cut only part-way 45 through the Bange, so that the flange will hold the fin plate in place and the n metal at this point will be fluxed with the metal of the tubeduring .the welding operation. Inasmuch as the flange on each plate, when employed, provides a m good bearing surface on the tube and maygripv the same with alight press fit, tack or'spot welding of flanges is suiilcient formany uses. On the other hand, the flanges may be used only as spacer members, not welded to the tube, conduction between the tube and iin being established by welding the iln to the tube at the inner ends of the slots, such as of slots 3 and 3a shown in the drawing.
Where desired, the fianges of the ilns may be welded to the tube at points intermediate the slots by making a step rotation oi' either the welding head or the tube assembly as the welding head advances in relation to the tube. The step rotation may, for example, be of 30, 45 or 60 degrees, more or less.
In addition to fins of the particular types illustrated in the drawing, it will be understood that my invention is applicable in the case of other ns which extend around or substantially around a tube or conduit whether they are rectangular, round or of other peripheral contour and whether, in a plane perpendicular to the length of the tube, they are generally fiat, curved. etc., so long as my above-described method of joining fins to a tube is applicable. f
The uses for which nned tubes as described may be employed are many and varied. They may be used where there is a fluid inside the tube and a solid material surrounding the tube, or vice versa, or where there are iluids both within and around the tube, or where there are solids both within and around the tube, where it is desired to eect the exchange of heat between points within the tube and points exterior thereto. For example, by way of speeic illustration, finned tubes or conduits constructedas herein illustrated may be employed in controlling the temperatures of catalytic beds or masses, e. g., in apparatus such as shown in Patent. No. 2,078,947, issued to myself on May 4, 1937 or in my copending application VSerial No. 84,787, filed June 12, 1936 which issued on June 27, 1939, as Patent No. 2,163,599. Again, my invention may be employed in constructing tubular nned members for various other particular uses involving heat exchange, for example those illustrated in Patents Nos. 855,239, issued to J. F. Faries on May 28, 1907, 1,920,800, issued to J. W. McCausland on August l, 1933, or 1,838,105 issued to T. E. Murray on December 29, 1931.
The tubes or conduits on which the fins are attached obviously are not limited to single-walled tubes but include other types of conduits, e. g., double or nested conduit assemblies such as shown in Patent No. 1,987,903, issued to myself on Januaryl, 1935, or conduits of the type illustrated in my\ aforementioned Patent No. 2,078,947 or my aforementioned copending application.
What I claim is:
1. In the construction of a tube with a series of transverse iins attached thereto, the steps which compris'e sliding centrally punched fins onto said tube with spacer members between adjacent fins to maintain them in desired spaced relationship, said fins having slots extending from the peripheries of the ns to points adjacent their central openings but not completely severing the fins into sections, positioning said ns with their slots ln alignment along the length of the tube, and passing a welding tool through the aligned slots so as to join said series of fins to said tube.
2. In a method of providing a tube with transverse ns, the steps o1' forming ilanged apertures in metal plates, providing slots in each plate from the periphery to points adjacent the aperture and grooves' in the outer wall of each flange in line with the slots, positioning the plates on the tubethrough the apertures and spacing the plates by means of the aperture flanges, aligning the slots of each plate and Joining the plates to 'the tube by fusing the grooved areas of the flanges to the tube.
3. In a method of providing a metal tube with transverse fins, the steps of forming a flanged aperture in metal plates, slotting each plate inwardly from the outer edge to provide a plurality of interconnected segments, positioning the segmented plates on the tube in spaced relation and aligning the slots, joining the tube and segmented plates by passing a welding tool through the aligned slots between adjacent segments of each plate and fusing the tube and segments at the Joining line.
4. Inthe construction of a metallic core with transverse fins, the steps of forming an aperture in a plurality of plates, slotting each plate from its periphery to points adjacent the aperture presenting segments interconnected by a continuous web portion, positioning the plates on the core in spaced relation and aligning the slots of the plates, and securing the plates by fusing the web portion with the core.
5. A finned heat exchange device adapted f emcient heat transfer comprising a conduit for conveying fluid, apertured plates extending transversely of the conduit, each plate having the apertures provided with spacing flanges and slots outwardly thereof. said slots extending from the outer edge of the plate to said flange forming segments of extensive heat exchange surface, and a welded joint between the segments for securing each plate integrally to the conduit with the slots in alignment. l
EUGENE J. HOUDRY.
US155186A 1937-07-23 1937-07-23 Heat exchange member and method of making Expired - Lifetime US2216778A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US155186A US2216778A (en) 1937-07-23 1937-07-23 Heat exchange member and method of making

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US155186A US2216778A (en) 1937-07-23 1937-07-23 Heat exchange member and method of making

Publications (1)

Publication Number Publication Date
US2216778A true US2216778A (en) 1940-10-08

Family

ID=22554412

Family Applications (1)

Application Number Title Priority Date Filing Date
US155186A Expired - Lifetime US2216778A (en) 1937-07-23 1937-07-23 Heat exchange member and method of making

Country Status (1)

Country Link
US (1) US2216778A (en)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2418619A (en) * 1943-08-11 1947-04-08 Brown Fintube Co Finned tube
US2423697A (en) * 1943-12-24 1947-07-08 Ice Air Conditioning Co Inc Method of assembling headers and tubes
US2444192A (en) * 1942-05-11 1948-06-29 Robertshaw Fulton Controls Co Manufacture of damped bellows
US2475604A (en) * 1943-11-02 1949-07-12 Foster Wheeler Corp Heat exchange apparatus
US2737370A (en) * 1949-07-09 1956-03-06 Frisch Martin Extended surface element for heat exchanger
US2965555A (en) * 1956-09-28 1960-12-20 Atomic Energy Authority Uk Heat transfer systems
US3011466A (en) * 1955-05-04 1961-12-05 Modine Mfg Co Method of making a fin collar
EP0252019A1 (en) * 1986-05-15 1988-01-07 Gaetano Piazzola Assemblable modular element heat exchanger
US4928756A (en) * 1988-08-04 1990-05-29 Spectra-Physics Heat dissipating fin and method for making fin assembly
US4986345A (en) * 1988-02-09 1991-01-22 Nissan Motor Co., Ltd. Rotary heat exchanger
US20020084062A1 (en) * 2000-12-28 2002-07-04 Chen Yun Lung Heat sink assembly
US6435266B1 (en) * 2001-05-01 2002-08-20 Aavid Taiwan Inc. Heat-pipe type radiator and method for producing the same
US6550529B1 (en) * 2002-04-17 2003-04-22 Sunonwealth Electric Machine Industry Co., Ltd. Heatsink device
US6640888B1 (en) * 2002-10-16 2003-11-04 Sunonwealth Electric Machine Industry Co., Ltd. Heat sink
US20050039890A1 (en) * 2003-08-08 2005-02-24 Lee Hsieh Kun Heat dissipating device and method of making it
US20050056470A1 (en) * 2003-09-16 2005-03-17 Jeong Lim Ho Cooling system for fuel cell vehicle and a cooling pipe thereof
US20080115915A1 (en) * 2006-11-16 2008-05-22 Ryan Chen Heat sink
US20110000641A1 (en) * 2009-07-06 2011-01-06 Xiaozhen Zeng Radiating fin structure and heat sink thereof
US20110297356A1 (en) * 2010-06-07 2011-12-08 Foxconn Technology Co., Ltd. Heat dissipation device

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2444192A (en) * 1942-05-11 1948-06-29 Robertshaw Fulton Controls Co Manufacture of damped bellows
US2418619A (en) * 1943-08-11 1947-04-08 Brown Fintube Co Finned tube
US2475604A (en) * 1943-11-02 1949-07-12 Foster Wheeler Corp Heat exchange apparatus
US2423697A (en) * 1943-12-24 1947-07-08 Ice Air Conditioning Co Inc Method of assembling headers and tubes
US2737370A (en) * 1949-07-09 1956-03-06 Frisch Martin Extended surface element for heat exchanger
US3011466A (en) * 1955-05-04 1961-12-05 Modine Mfg Co Method of making a fin collar
US2965555A (en) * 1956-09-28 1960-12-20 Atomic Energy Authority Uk Heat transfer systems
EP0252019A1 (en) * 1986-05-15 1988-01-07 Gaetano Piazzola Assemblable modular element heat exchanger
US4986345A (en) * 1988-02-09 1991-01-22 Nissan Motor Co., Ltd. Rotary heat exchanger
US4928756A (en) * 1988-08-04 1990-05-29 Spectra-Physics Heat dissipating fin and method for making fin assembly
US20020084062A1 (en) * 2000-12-28 2002-07-04 Chen Yun Lung Heat sink assembly
US7121327B2 (en) * 2000-12-28 2006-10-17 Hon Hai Precision Ind. Co., Ltd. Heat sink assembly
US6435266B1 (en) * 2001-05-01 2002-08-20 Aavid Taiwan Inc. Heat-pipe type radiator and method for producing the same
US6550529B1 (en) * 2002-04-17 2003-04-22 Sunonwealth Electric Machine Industry Co., Ltd. Heatsink device
US6640888B1 (en) * 2002-10-16 2003-11-04 Sunonwealth Electric Machine Industry Co., Ltd. Heat sink
US20050039890A1 (en) * 2003-08-08 2005-02-24 Lee Hsieh Kun Heat dissipating device and method of making it
US20050056470A1 (en) * 2003-09-16 2005-03-17 Jeong Lim Ho Cooling system for fuel cell vehicle and a cooling pipe thereof
US7258939B2 (en) * 2003-09-16 2007-08-21 Hyundai Motor Company Cooling system for fuel cell vehicle and a cooling pipe thereof
US20080115915A1 (en) * 2006-11-16 2008-05-22 Ryan Chen Heat sink
US20110000641A1 (en) * 2009-07-06 2011-01-06 Xiaozhen Zeng Radiating fin structure and heat sink thereof
US20110297356A1 (en) * 2010-06-07 2011-12-08 Foxconn Technology Co., Ltd. Heat dissipation device
US8453716B2 (en) * 2010-06-07 2013-06-04 Furui Precise Component (Kunshan) Co., Ltd. Heat dissipation device

Similar Documents

Publication Publication Date Title
US2216778A (en) Heat exchange member and method of making
US3636982A (en) Internal finned tube and method of forming same
US2573161A (en) Heat exchanger
US2692763A (en) Supporting spacer for annular corrugated fins
US2778610A (en) Catalyst finned tubing and method of making
US4692979A (en) Heat exchanger and a method and apparatus for the manufacture thereof
US5722485A (en) Louvered fin heat exchanger
US3668757A (en) Method of forming a heat exchanger
US2171253A (en) Tubular radiator
JPH0634282A (en) Heat exchanger and manufacture thereof and header tube for heat exchanger and manufacture thereof
US4300630A (en) Finned metal tube and method for making the same
US1943557A (en) Heat exchange device
CA1052988A (en) Method of forming a header assembly
US2355621A (en) Finned tube
US2722048A (en) Method of making heat exchangers
US3266567A (en) Heat exchanger
US5117905A (en) Heat exchanger with fins
JPS6166091A (en) Manufacture of heat exchanger tube material and core by use of such material and core by use of such material
US2418619A (en) Finned tube
US2433731A (en) Process of making heat transfer units
US2414159A (en) Radiator construction
JPS58164995A (en) Heat exchanger and manufacture thereof
US2362694A (en) Method of manufacturing tubes for heat exchange devices
US2153806A (en) Method of forming a heat exchange device
US2161898A (en) Finned tube and method for forming the same