US3724062A - Explosively welded plug for leaky tubes of a heat exchanger and method of using the same - Google Patents

Explosively welded plug for leaky tubes of a heat exchanger and method of using the same Download PDF

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Publication number
US3724062A
US3724062A US00125514A US3724062DA US3724062A US 3724062 A US3724062 A US 3724062A US 00125514 A US00125514 A US 00125514A US 3724062D A US3724062D A US 3724062DA US 3724062 A US3724062 A US 3724062A
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US
United States
Prior art keywords
plug
tube
cavity
set forth
explosive charge
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
US00125514A
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English (en)
Inventor
R Cantrell
L Sturiale
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.)
CBS Corp
Original Assignee
Westinghouse Electric Corp
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Filing date
Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
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Publication of US3724062A publication Critical patent/US3724062A/en
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Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/06—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating by means of high energy impulses, e.g. magnetic energy
    • B23K20/08—Explosive welding
    • B23K20/085—Explosive welding for tubes, e.g. plugging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L41/00—Branching pipes; Joining pipes to walls
    • F16L41/08—Joining pipes to walls or pipes, the joined pipe axis being perpendicular to the plane of the wall or to the axis of another pipe
    • F16L41/082—Non-disconnectible joints, e.g. soldered, adhesive or caulked joints
    • F16L41/084—Soldered joints
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F11/00—Arrangements for sealing leaky tubes and conduits
    • F28F11/02—Arrangements for sealing leaky tubes and conduits using obturating elements, e.g. washers, inserted and operated independently of each other
    • Y—GENERAL 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4935—Heat exchanger or boiler making
    • Y10T29/49352—Repairing, converting, servicing or salvaging

Definitions

  • This invention relates to a method and plug for plugging a leaky tube in a heat exchanger and more particularly to a plug which is explosively welded to the inside diameter of the tube and a method of utilizing such a plug.
  • Explosive welding generally employs a cold bonding, plastic flow phenomenon, which allows a large number of similar or dissimilar metals to be strongly bonded together without elaborate surface preparation.
  • Tubular heat exchangers are utilized to transfer heat between two fluids in processes in which it is undesirable to mix the fluids. Occasionally one of the tubes springs a leak due to corrosion or due to latent defects in the tube. Because it is very difficult or almost impossible to replace a leaky tube without disassembling the heat exchanger, the ends of the leaky tube are generally plugged by driving plugs of some type into the tube.
  • the simplest plug being a tapered bar, which is driven into the tube with a hammer and seal welded thereto.
  • to drive such plugs there must be sufficient room to swing the hammer and make a seal weld and a workman must remain in close proximity to the tube and tube sheet for an extended period of time in order to properly seal the plug.
  • a plug for an end of a leaky tube of a heat exchanger made in accordance with this invention is formed from a metal capable of being welded to the tube by a shock wave propagated by an explosive charge.
  • a plug comprises a forward portion adapted to center the forward end of the plug in the tube, a central portion having an outer peripheral surface formed to provide generally equal spacings between the peripheral surface and the tube, a rear portion having a frustoconical shape adapted to center the plug within the tube and position the plug relative to the end of the tube and a central cavity having an axial opening which extends through the rear portion and the central portion of the plug and partially into the forward portion.
  • An explosive charge is disposed in that portion of the cavity adjacent the center portion of the plug and a detonating cord is in communication with the explosive charge to detonate the explosive charge and explosively weld the plug to the tube.
  • This invention also includes a method of utilizing such a plug to seal off one end ofa leaky tube.
  • FIG. 1 is a partial sectional view of a heat exchanger tube sheet showing a plug made in accordance with this invention before being explosively welded to one end of a leaky tube;
  • FIG. 2 is a partial sectional view of a heat exchanger tube sheet showing the plug explosively welded to the end of a leaky tube;
  • FIG. 3 is a sectional view of a modified plug.
  • FIG. 1 shows a heat exchanger tube sheet 1 having a plurality of tubes 3 extending therethrough.
  • a plug 5 is disposed in the end of the central tube so that it may be explosively welded thereto.
  • the plug isshown to comprise a forward portion 7 having a diameter slightly less than the diameter of the tube 3 to generally center the forward portion 7 of the plug 5 in the tube; a central portion 9 having a neckdown section having a peripheral surface 11, which is generally spaced an equal distance from the surface 13 of the tube 3; and a rear portion 15 having a frustoconical peripheral surface 17 which centers the rear portion of the tube 3 and positions the plug 5 relative to the end of the tube so that the center portion of the plug is adjacent the tube sheet 1.
  • An axial bore 19 provides a cavity, which extends through the rear and central portion 15 and 9, respectively, and partially into the forward portion 7.
  • the explosive charge 20 is contained by wadding 23 and 25.
  • the forward wadding 23 blocks the forward portion of the cavity 19 and the rear wadding 25 blocks the rear portion of the cavity 19 confining the explosive charge to the central portion of the cavity 19.
  • a detonating cord or Primacord 27, such as a 25 or 50 grain per foot Cordeau detonating cord extends through the rear wadding 25 and is in contact with the explosive charge 20.
  • a blasting cap 29 is taped to the detonating cord 27 and electrically connected to an electric blasting machine 30 via conductors L1 and L2. The electrical blasting machine 30, when activated, will detonate the blasting cap 29 to ignite the detonating cord 27 and detonate the explosive charge 20 which propagates a shock wave.
  • the peripheral surface 11 of the central portion 9 of the plug 5 is disposed an equal distance from the tube 3 so that the shock wave propagated by the detonation of the explosive charge will progress from adjacent the rear portion 15 of the plug 5 to adjacent the forward portion 7 of the plug 5.
  • This causes expansion of the central portion 9 of the plug 5 to initiate adjacent the rear portion and progress to the forward portion 7 in such a manner that the peripheral surface 11 of the central portion 9 of the plug 5 will progressively contact the inner surface 13 of the tube 3 at sufficiently high velocity so that there is plastic flow at the interface of the surfaces as they come into contact to provide a weld between these surfaces.
  • the weld thus formed is strong and essentially free of voids and inclusions of foreign material, due to a jetting effect caused by the rapid collapse of the included angle between the interacting surfaces as the expansion of the thin wall portion 21 of the plug progresses.
  • FIG. 2 generally shows the shape of the plug 5 after it is explosively welded to the tube 3.
  • FIG. 3 shows a modification of the plug shown in FIG. 1.
  • the center and rear portions 9 and 15 respectively are generally the same as the center and rear portions of the plug shown in FIG. 1.
  • the forward portion 7' in the modified plug has a bore 31 extending partially therein from the forward end thereof.
  • the wall 35 of the bore 31 has kerfs 37 spaced girthwise thereon to permit end segments of the wall 35 to be flared outwardly to provide leaf springs for centering the plug 5' within the tube 3 and holding the plug in position prior to detonating the explosive charge.
  • the rear portion 15 of the plug 5 has a frustoconical peripheral surface so that the plug may be made to a nominal size and yet centered accurately in tubes having openings which vary several thousandths in diameter to provide generally uniform spacing between the central portion 9 of the plug 5' and the tube 3 to locate the plug relative to the end of the tube and firmly hold the plug in place prior to explosively welding it to the tube.
  • a method of plugging a leaking tube utilizing a plug made in accordance with this invention comprises the following steps;
  • a plug for an end of a tube said plug being formed of a material capable of being welded to said tube by a shock wave propagated by an explosive charge, said plug comprising three integral portions,
  • an explosive charge disposed in a portion of said cavity adjacent said center portion of said plug, wadding disposed in said cavity to keep said explosive charge adjacent said center portion, and means for detonating said explosive charge.
  • said wall being substantially thinner than the walls of the forward and rear portions.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)
  • Pipe Accessories (AREA)
  • Butt Welding And Welding Of Specific Article (AREA)
US00125514A 1971-03-18 1971-03-18 Explosively welded plug for leaky tubes of a heat exchanger and method of using the same Expired - Lifetime US3724062A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12551471A 1971-03-18 1971-03-18

Publications (1)

Publication Number Publication Date
US3724062A true US3724062A (en) 1973-04-03

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ID=22420064

Family Applications (1)

Application Number Title Priority Date Filing Date
US00125514A Expired - Lifetime US3724062A (en) 1971-03-18 1971-03-18 Explosively welded plug for leaky tubes of a heat exchanger and method of using the same

Country Status (8)

Country Link
US (1) US3724062A (de)
JP (1) JPS5428422Y2 (de)
AT (1) AT318329B (de)
BE (1) BE780829A (de)
CH (1) CH537553A (de)
DE (1) DE2210227C3 (de)
FR (1) FR2129771A5 (de)
IT (1) IT950356B (de)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3912148A (en) * 1974-04-30 1975-10-14 Babcock & Wilcox Co Combination welding and brazing device
US4021907A (en) * 1974-09-16 1977-05-10 Explosive Metal Working Holland B.V. Method of sealing apertures in tube plates of heat exchangers using explosive plug
US4074630A (en) * 1976-02-27 1978-02-21 Explosive Metal Working Holland B.V. Methods and plugs to seal apertures in tube plates of heat exchangers provided with tube plates which are locally sealed with these methods and such plates
US4106687A (en) * 1972-09-14 1978-08-15 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Totally confined explosive welding
US4347965A (en) * 1979-03-28 1982-09-07 Gershon Grossman Method of connecting thin metal sheets to metal tubes
US4347790A (en) * 1979-07-11 1982-09-07 Cockerill And Centre De Technologies Nouvelles Explosive plug for blocking tubes
US4587904A (en) * 1985-01-07 1986-05-13 Foster Wheeler Energy Corporation Debris free plug assembly for heat exchange tubes
US4708280A (en) * 1985-10-23 1987-11-24 The United States Of America As Represented By The Administrator, National Aeronautics & Space Administration Tool and process for miniature explosive joining of tubes
US4762674A (en) * 1984-12-27 1988-08-09 Westinghouse Electric Corp. Brazing sleeve having ceramic flux band and method for applying same
US5479961A (en) * 1994-12-09 1996-01-02 Senior Engineering Company Method of plugging a heat exchanger tube and plug therefor
EP0753714A3 (de) * 1995-07-11 1997-12-29 Valeo Engine Cooling, Inc. Verfahren zum Zusammenbau eines Wärmetauschers und Rohrstopfen für Wärmetauscher
US5715598A (en) * 1995-12-13 1998-02-10 Westinghouse Electric Corporation Method for sealing a bare hole defined by a nuclear heat exchanger tubesheet
US20100089546A1 (en) * 2008-10-09 2010-04-15 Gm Global Technology Operations, Inc. Vehicle heat exchangers having shielding channels
US8967234B2 (en) 2010-11-15 2015-03-03 Saudi Arabian Oil Company Tube plug for a heat exchanger tube

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4113315A1 (de) * 1991-04-24 1992-10-29 Klaus Pomorin Rohrduebelpatrone

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3491798A (en) * 1967-01-17 1970-01-27 Texaco Inc Explosive type expansible plug
US3543370A (en) * 1968-05-08 1970-12-01 Foster Wheeler Corp Method and apparatus for explosively forming a tube within a tube sheet
US3555656A (en) * 1967-05-25 1971-01-19 Westinghouse Electric Corp Method of explosively plugging a leaky metal tube in a heat exchanger tube bundle
US3562897A (en) * 1968-11-27 1971-02-16 Du Pont Explosion bonding of tubes
US3562887A (en) * 1968-05-08 1971-02-16 Foster Wheeler Corp Explosive expansion of liner sleeves
US3590877A (en) * 1968-09-20 1971-07-06 Babcock & Wilcox Co Explosive-activated plug

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3491798A (en) * 1967-01-17 1970-01-27 Texaco Inc Explosive type expansible plug
US3555656A (en) * 1967-05-25 1971-01-19 Westinghouse Electric Corp Method of explosively plugging a leaky metal tube in a heat exchanger tube bundle
US3543370A (en) * 1968-05-08 1970-12-01 Foster Wheeler Corp Method and apparatus for explosively forming a tube within a tube sheet
US3562887A (en) * 1968-05-08 1971-02-16 Foster Wheeler Corp Explosive expansion of liner sleeves
US3590877A (en) * 1968-09-20 1971-07-06 Babcock & Wilcox Co Explosive-activated plug
US3562897A (en) * 1968-11-27 1971-02-16 Du Pont Explosion bonding of tubes

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Gipson, Donald H., An Explosively Driven Pipe Closure, University of California Radiation Laboratory Report 12203, TID 4500 (37th Ed.), 4/65 *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4106687A (en) * 1972-09-14 1978-08-15 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Totally confined explosive welding
US3912148A (en) * 1974-04-30 1975-10-14 Babcock & Wilcox Co Combination welding and brazing device
US4021907A (en) * 1974-09-16 1977-05-10 Explosive Metal Working Holland B.V. Method of sealing apertures in tube plates of heat exchangers using explosive plug
US4074630A (en) * 1976-02-27 1978-02-21 Explosive Metal Working Holland B.V. Methods and plugs to seal apertures in tube plates of heat exchangers provided with tube plates which are locally sealed with these methods and such plates
US4347965A (en) * 1979-03-28 1982-09-07 Gershon Grossman Method of connecting thin metal sheets to metal tubes
US4347790A (en) * 1979-07-11 1982-09-07 Cockerill And Centre De Technologies Nouvelles Explosive plug for blocking tubes
US4762674A (en) * 1984-12-27 1988-08-09 Westinghouse Electric Corp. Brazing sleeve having ceramic flux band and method for applying same
US4587904A (en) * 1985-01-07 1986-05-13 Foster Wheeler Energy Corporation Debris free plug assembly for heat exchange tubes
US4708280A (en) * 1985-10-23 1987-11-24 The United States Of America As Represented By The Administrator, National Aeronautics & Space Administration Tool and process for miniature explosive joining of tubes
US5479961A (en) * 1994-12-09 1996-01-02 Senior Engineering Company Method of plugging a heat exchanger tube and plug therefor
EP0753714A3 (de) * 1995-07-11 1997-12-29 Valeo Engine Cooling, Inc. Verfahren zum Zusammenbau eines Wärmetauschers und Rohrstopfen für Wärmetauscher
US5715598A (en) * 1995-12-13 1998-02-10 Westinghouse Electric Corporation Method for sealing a bare hole defined by a nuclear heat exchanger tubesheet
US20100089546A1 (en) * 2008-10-09 2010-04-15 Gm Global Technology Operations, Inc. Vehicle heat exchangers having shielding channels
US8967234B2 (en) 2010-11-15 2015-03-03 Saudi Arabian Oil Company Tube plug for a heat exchanger tube

Also Published As

Publication number Publication date
DE2210227A1 (de) 1972-09-21
BE780829A (fr) 1972-09-18
JPS5348128U (de) 1978-04-24
IT950356B (it) 1973-06-20
DE2210227B2 (de) 1980-05-29
JPS5428422Y2 (de) 1979-09-12
CH537553A (de) 1973-05-31
FR2129771A5 (de) 1972-10-27
AT318329B (de) 1974-10-10
DE2210227C3 (de) 1981-02-05

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