US3785291A - Device for closing off defective heat exchanger tubes - Google Patents

Device for closing off defective heat exchanger tubes Download PDF

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Publication number
US3785291A
US3785291A US00253853A US3785291DA US3785291A US 3785291 A US3785291 A US 3785291A US 00253853 A US00253853 A US 00253853A US 3785291D A US3785291D A US 3785291DA US 3785291 A US3785291 A US 3785291A
Authority
US
United States
Prior art keywords
plug
tube
sleeve
heat exchanger
surface portion
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
US00253853A
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English (en)
Inventor
G Seyd
A Bergbauer
M Ploger
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Siemens AG
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Siemens AG
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Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
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Publication of US3785291A publication Critical patent/US3785291A/en
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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
    • 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
    • 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
    • Y10T29/49805—Shaping by direct application of fluent pressure
    • Y10T29/49806—Explosively shaping

Definitions

  • the device for closing off a defective heat exchanger tube includes a metallic plug having a blind hole in which a sleeve of plastic, cardboard or the like is mounted.
  • the plug has a cylindrical cross-section at the forward end to fit in the tube and a conically tapered outer surface at the open end.
  • the sleeve encloses an explosive charge within the plane of the conically tapered outer surface of the plug and is provided with an enlarged end portion which projects from the plug. This end portion is conically tapered and slotted to jam in the heat exchanger tube. Upon detonation, 'the explosive charge expands and welds the conically tapered surface portion of the pllug to the heat exchanger tube to close off the end of the tube.
  • a primary coolant is usually circulated through a reactor system in order to cool down a reactor core by taking on heat. After passing from the reactor core, the primary coolant has been passed through a heat exchanger in heat exchange relation with a secondary coolant passing through the heat exchangerfor various purposes, such as the generation of steam from the secondary coolant.
  • the primary coolant can unavoidably become radioactively contaminated with a resultant depositing of radioactive particles in the area of the heat exchanger.
  • there e is the danger that the heat exchanger tubes may break so that a direct connection then exists between the primary coolant and the secondary coolant. This has the immediate consequence that radioactivity can get into the secondary circuit and must, therefore, be avoided at all costs.
  • the device includes a metallic plug which is to be inserted into a tube ofa heat exchanger to be sealed off.
  • the plug which is of a cylindrical cross-section with a diameter to fit into the tube is provided with a blind hole as well as a conically tapered surface portion at the open end.
  • the device includes a sleeve made of plastic, cardboard, or the like which is placed, in part, within the blind hole of the plug and has a conically enlarged end projecting from the plug. This enlarged end is slotted longitudinally to enable the device to be jammed into the heat exchanger tube.
  • the sleeve contains a detonator cap in the part facing the end of the blind hole in the plug and an explosive charge in a central part which is located within the conically tapered surface portion of the plug.
  • the device In use, after entrance is gained to a bank of heat exchanger tubes, the device is inserted into the open end of the tube to be closed off. In this manner the forward end of the plug is slid into the tube until the enlarged end of the sleeve becomes jammed in the tube. Thereafter, the detonator cap is activated by a suitable means, such as through ignition wires. The detonator cap then activates the explosive charge which, in turn, causes a detonation shock wave to travel along the tapered surface portion of the plug. This shock wave circumferentially expands the tapered surface portion against the inside wall of the tube while also welding the plug to the tube. Thereafter, the materials remaining in the blind hole of the plug can be removed. The opposite open end ofthe tube is also closed off in a similar manner.
  • FIG. 1 schematically illustrates a heat exchanger in which a tube has been closed offin accordance with the invention
  • FIG. 2 illustrates a cross-sectional view of a device according to the invention.
  • FIG. 3 illustrates a cross-sectional view of a heat exhcnager tube and a plug welded within the tube to seal off the tube in accordance with the invention.
  • the heat exchanger in general consists of a pressure tank I which is divided into two parts by a tube plate 15.
  • a plurality of U- shaped heat exchanger tubes 17 through which a primary coolant flows are mounted to one side of the tube plate 15 and have open ends which pass through the tube plate 15 to communicate with the opposite side.
  • the space underneath the tube plate 15 is further subdivided by a partition 16 into two plenum chambers which serve to receive the entering and leaving primary coolant respectively.
  • the primary coolant is fed into one plenum chamber via a connection 11 and, after passing through the tubes 17, is discharged via a connection 12.
  • the tank 1 is also provided with suitable manholes 19 to provide access to the respective plenum chambers.
  • the pressure tank 1 also includes a connection 13 above the tube plate 15, as viewed, through which a secondary coolant is fed into the tank to flow around the heat exchanger tubes 17 in heat exchange relation with the primary coolant therein. Also, a connection 14 is provided for the discharge of the secondary coolant in the top of the pressure tank 1, as viewed.
  • a fault for instance at point 18, is not directly accessible for repair. As such a fault occurs with greater probability in the curved parts of the heat exchanger tubes 17, it is practically impossible to make repairs even by means of special tools from the inside of the tube. Therefore, there remains only one possibility, namely, to close off the defective tube at both its ends, i.e., within the region of the tube plate 15, as is indicated by the plugs 2.
  • each plug 2 is constructed in a very special manner to form a joint with the inner wall ofa defective tube 17 according to the principle of explosion welding.
  • the plug 2 consists of a generally cylindrical metal piece or body 21 which is provided with a central recess or blind hole 23.
  • the plug 2 also has a conically tapered surface portion 22 at the open end which has an angular taper a of between 2 and 6.
  • each plug 2 is fitted with a sleeve 3 of plastic, cardboard or similar material within the blind hole 23.
  • the sleeve 3 has a coneshaped enlarged rear end 33 which extends away from the open end of the plug 2 in shoulder-like fashion. This enlarged end 33 is also provided with longitudinal slots 34 by which the sleeve 3 is welded or jammed into a tube to be sealed off.
  • the plug 2 and sleeve 3 thus form a unitary device which can be inserted into the end of a heat exchanger tube 17.
  • a detonator cap 4 is mounted in the front end of the sleeve 3 and an explosive charge 5 is mounted in a central part of the sleeve 3.
  • the explosive charge 5 is ofa length corresponding approximately to the length of the tapered surface portion 22 of the plug 2 and is located concentrically within the plane of this portion of the plug 2.
  • This device also has ignition wires 41 which are connected to the detonator cap 4 and are led out along the detonator cap 4 and the explosive charge 5, for instance, in a lateral slot of the sleeve 3.
  • the invention thus provides a device which can be used to close off defective tubes extremely fast. Further, the device of the invention can be easily handled manually and can, of course, also be used via remotely controlled manipulators should the radiation level in the plenum chambers be too high for operating personnel.
  • the plug 2 may have, for instance, a length of l 10 millimeters (mm).
  • the blind hole 23 then has an inside diameter of 13 millimeters (mm) and a depth of about millimeters (mm).
  • the length of the explosive charge 5 and also of the conical part 22 of the plug 2 is about 30 millimeters (mm).
  • the length of the sleeve 3 extending into the blind hole 23 depends on the size of the detonator cap 4 used.
  • the quantity of explosive 5 must be determined by appropriate preliminary tests and also depends on the material of the heat exchanger tubes and of the plugs 2, respectively.
  • both the tube and plug parts will be made of the same material.
  • the difference in the coeffici ents of thermal expansion between the material of the tube and that of the plug should be as small as possible.
  • the magnitude of the angle a for the conical surface portion 22 at the plug 2 depends here on the detonation velocity of the explosive used, i.e., on its type. In genera], the angle a is between 2 and 6 and will be the larger, the greater the detonation velocity of the explosive used.
  • the wall thickness of the plug as well as the conicity of the open end are essential for the success of this explosive-seal welding technique.
  • a device for closing off an end of a tube comprising a metallic plug having a forward peripheral surface portion of cylindrical cross-section, a conically tapered rear surface portion of predetermined angle and a blind hole extending from a rear end thereof into the plane of said forward surface portion;
  • a sleeve having a forward end positioned in said blind hole and an enlarged rear end projecting away from said rear end of said plug, said enlarged end having a cone-shaped outer surface and a plurality of slots therein for jamming into the end of a tube to mount said plug in the tube;
  • an explosive charge of predetermined detonation velocity within said sleeve and within the plane of said conically tapered rear surface portion of said angle increases with increasing detonation velocity.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Butt Welding And Welding Of Specific Article (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
US00253853A 1971-05-18 1972-05-16 Device for closing off defective heat exchanger tubes Expired - Lifetime US3785291A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2124530A DE2124530C3 (de) 1971-05-18 1971-05-18 Einrichtung zum Verschließen schadhafter Wärmetauseherrohre

Publications (1)

Publication Number Publication Date
US3785291A true US3785291A (en) 1974-01-15

Family

ID=5808182

Family Applications (1)

Application Number Title Priority Date Filing Date
US00253853A Expired - Lifetime US3785291A (en) 1971-05-18 1972-05-16 Device for closing off defective heat exchanger tubes

Country Status (11)

Country Link
US (1) US3785291A (es)
JP (1) JPS5646157Y2 (es)
BE (1) BE783378A (es)
CH (1) CH532768A (es)
DE (1) DE2124530C3 (es)
ES (1) ES402821A1 (es)
FR (1) FR2137905B1 (es)
GB (1) GB1387293A (es)
IT (1) IT955602B (es)
NL (1) NL173094C (es)
SE (1) SE369859B (es)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3919940A (en) * 1972-08-25 1975-11-18 Siemens Ag Explosive-activated plug
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
US4030419A (en) * 1975-11-20 1977-06-21 Westinghouse Electric Corporation Insert for explosively expanding a tube into engagement with a tube sheet
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
US4237937A (en) * 1979-03-12 1980-12-09 Quabbin Industries, Inc. Device for sealing damaged tubular members
US4249577A (en) * 1979-09-10 1981-02-10 Davis James W Process and apparatus for sealing gas lines
US4347790A (en) * 1979-07-11 1982-09-07 Cockerill And Centre De Technologies Nouvelles Explosive plug for blocking tubes
US4685205A (en) * 1985-08-26 1987-08-11 Foster Wheeler Development Corporation Apparatus for forming an explosively expanded tube-tube sheet joint including a barrier tube
US5566444A (en) * 1994-03-14 1996-10-22 Korea Heavy Industries & Construction Company Tube-plugging assembly
US5841060A (en) * 1995-10-24 1998-11-24 Skaggs; Roger Dean Blast plug
US20020121139A1 (en) * 2001-03-02 2002-09-05 Purpura Paul E. Adapter for holding a sample container to facilitate sensing of liquid level in the sample container
US20070180814A1 (en) * 2006-02-03 2007-08-09 General Electric Company Direct liquid fuel injection and ignition for a pulse detonation combustor
US8967234B2 (en) 2010-11-15 2015-03-03 Saudi Arabian Oil Company Tube plug for a heat exchanger tube

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1984001118A1 (en) * 1982-09-24 1984-03-29 Babcock & Wilcox Co Explosive welding device
FR2604771B1 (fr) * 1986-10-06 1989-01-27 Framatome Sa Dispositif de bouchage etanche d'un orifice traversant une paroi

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3543387A (en) * 1967-12-01 1970-12-01 Euratom Method for the explosive welding of a metal plug to a metal tube or of nested portions of metal tubes to each other
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
US3562887A (en) * 1968-05-08 1971-02-16 Foster Wheeler Corp Explosive expansion of liner sleeves

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US3543387A (en) * 1967-12-01 1970-12-01 Euratom Method for the explosive welding of a metal plug to a metal tube or of nested portions of metal tubes to each other
US3562887A (en) * 1968-05-08 1971-02-16 Foster Wheeler Corp Explosive expansion of liner sleeves

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3919940A (en) * 1972-08-25 1975-11-18 Siemens Ag Explosive-activated plug
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
US4030419A (en) * 1975-11-20 1977-06-21 Westinghouse Electric Corporation Insert for explosively expanding a tube into engagement with a tube sheet
US4064618A (en) * 1975-11-20 1977-12-27 Westinghouse Electric Corporation Method of positioning an explosive insert in a vertical tube
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
US4237937A (en) * 1979-03-12 1980-12-09 Quabbin Industries, Inc. Device for sealing damaged tubular members
US4347790A (en) * 1979-07-11 1982-09-07 Cockerill And Centre De Technologies Nouvelles Explosive plug for blocking tubes
US4249577A (en) * 1979-09-10 1981-02-10 Davis James W Process and apparatus for sealing gas lines
US4685205A (en) * 1985-08-26 1987-08-11 Foster Wheeler Development Corporation Apparatus for forming an explosively expanded tube-tube sheet joint including a barrier tube
US5566444A (en) * 1994-03-14 1996-10-22 Korea Heavy Industries & Construction Company Tube-plugging assembly
US5841060A (en) * 1995-10-24 1998-11-24 Skaggs; Roger Dean Blast plug
US20020121139A1 (en) * 2001-03-02 2002-09-05 Purpura Paul E. Adapter for holding a sample container to facilitate sensing of liquid level in the sample container
US20070180814A1 (en) * 2006-02-03 2007-08-09 General Electric Company Direct liquid fuel injection and ignition for a pulse detonation combustor
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
NL173094B (nl) 1983-07-01
NL173094C (nl) 1983-12-01
DE2124530A1 (de) 1972-11-30
JPS5646157Y2 (es) 1981-10-28
SE369859B (es) 1974-09-23
CH532768A (de) 1973-01-15
DE2124530B2 (de) 1977-09-01
JPS5652196U (es) 1981-05-08
GB1387293A (en) 1975-03-12
FR2137905A1 (es) 1972-12-29
ES402821A1 (es) 1975-04-16
FR2137905B1 (es) 1975-04-11
BE783378A (fr) 1972-09-01
IT955602B (it) 1973-09-29
DE2124530C3 (de) 1978-04-27
NL7205954A (es) 1972-11-21

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