US3491798A - Explosive type expansible plug - Google Patents

Explosive type expansible plug Download PDF

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Publication number
US3491798A
US3491798A US609917A US3491798DA US3491798A US 3491798 A US3491798 A US 3491798A US 609917 A US609917 A US 609917A US 3491798D A US3491798D A US 3491798DA US 3491798 A US3491798 A US 3491798A
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US
United States
Prior art keywords
plug
tube
tubes
charge
centering
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
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US609917A
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English (en)
Inventor
John J Beshara
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.)
Texaco Inc
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Texaco Inc
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Publication date
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Publication of US3491798A publication Critical patent/US3491798A/en
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    • 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
    • F28F11/04—Arrangements for sealing leaky tubes and conduits using pairs of obturating elements, e.g. washers, mounted upon central operating rods
    • 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
    • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
    • F16L55/10—Means for stopping flow from or in pipes or hoses
    • F16L55/12—Means for stopping flow from or in pipes or hoses by introducing into the pipe a member expandable in situ
    • F16L55/128—Means for stopping flow from or in pipes or hoses by introducing into the pipe a member expandable in situ introduced axially into the pipe or hose
    • F16L55/13—Means for stopping flow from or in pipes or hoses by introducing into the pipe a member expandable in situ introduced axially into the pipe or hose the closure device being a plug fixed by plastic deformation
    • 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

Definitions

  • Heat exchangers of the type to which this invention is especially applicable are constructed with a large number of relatively small diameter tubes situated in a group that is commonly called a bundle. Heat is exchanged between fluids flowing inside and around the outside of the tube bundle. And, the fluids are maintained physically separated by using so called tube sheets, one at each end of the tube bundle. Consequently, it is common practice to repair a leaky tube by plugging it off at each end, and
  • Another object of the invention is to provide an explosive type of soft metal plug that may be remotely detonated and that includes means for centering same within a heat exchanger tube.
  • the invention concerns an expansible plug for use in heat exchanger tubes or the like, which comprises a cylindrical body having an outside diameter over the entire lengh thereof that is slightly less than the inside diameter of one of said tubes.
  • the plug also comprises an explosive charge withine said body, said body being constructed of ductile material having sutficient wall thickness to avoid rupture when said charge is detonated.
  • the plug also comprises means for detonating said charge when the plug is in place within a tube.
  • the invention concerns a method of plugging a leaky tube in a heat exchanger or the like, wherein said tube is attached at at least one end thereof to a tube sheet.
  • the method comprises the steps of taking an explosive type of plug having a charge therein, and inserting and coaxially centering said plug within said tube.
  • the method also comprises the steps of locating said plug so that said charge is within said tube sheet, and detonating said charge to plug the end of said tube within said tube sheet.
  • FIG. 1 is an elevation largely broken away in longitudinal cross-section, illustrating a typical heat exchanger having both stationary and floating tube sheets with a bundle of tubes between and to which structure the apparatus and method of subject invention is applicable;
  • FIG. 2 is an enlarged elevation illustrating schematically a plug according to the invention, having a flexibleshaft type tool for inserting the plug within a tube, shown partly broken away in cross-section;
  • FIG. 3 and FIG. 4 are cross-sectional views taken along the lines 33 and 44 of FIG. 2 looking in the direction of the arrows;
  • FIG. 5 is an enlarged scematic longitudinal crosssectional view illustrating a plug according to the invention, in place within a tube and inside the tube sheet at one end of the tube;
  • FIG. 6 is a similar view as FIG. 5 but showing the plug after it has been expanded by detonating its charge.
  • FIG. 1 illustrates a typical heat exchanger unit 15 to which an explosive plug according to this invention is particularly applicable. It will be observed that a heat exchanger of this type provides for exchange of heat between two fluids, one of which flows through the interior of a cylindrical bundle of tubes 11, while another fluid flows over the exterior of the tubes 11 within a shell 12.
  • the shell 12 has nozzles 13 and 14 for connecting the one fluid to the inside of the shell.
  • the fluid flowing through the interior of the tubes 11 is directed to pass back and forth through a series of different groups of the tubes by reason of providing the necessary pass partitions at the ends of the tubes.
  • a so-called stationary head 17 with an inlet 18 attached thereto At one end of the heat exchanger 15 there is a so-called stationary head 17 with an inlet 18 attached thereto.
  • This head has a number of pass partitions such as a partition 19, as shown, that will direct the fluid through a path within the uppermost group of tubes. That uppermost group of tubes are connected to the interior of the stationary head -17 above the partition 19, since these tubes are fastened to a stationary tube sheet 22 that forms one wall of the interior of the stationary head 17.
  • the other fluid will flow in contact with the outside of the tubes 11 of the bundle.
  • the flow path for this other fluid is from the nozzle 13 into the interior space of the shell 12. Then because of a series of bafi'les 31 this fluid will flow over a tortuous path along the length of the interior of shell 12. It will then flow out through nozzle 14 near the other end of the shell from the inlet nozzle 13.
  • a plug structure comprises a thick-walled cylinder 38 that has an outside diameter which is slightly less than the inside diameter of a given tube 11 into which it is to be placed for plugging same.
  • the interior of the plug 38 contains an explosive charge (not shown) with the arrangement such that there is a power charge near the nose end of the plug, while there are a plurality of sequential charges leading from a detonator charge to the power charge.
  • the specific arrangement of the charge and the related detonator and other charges is set up and designed for carrying out the desired expansion of the plug, without rupture of the walls thereof. This is important since a preferred embodiment of the invention relates to a use in hydrocarbon and other petroleum processes where there may be explosive fluids in one or both of the fluid paths through a heat exchanger wherein the invention is em- 'ployed. However, as already noted, all the design features including the size of charges employed, etc, form no part per se of the subject invention.
  • the walls of the plug i.e. of cylinder 38 are formed of a ductile material, e.g. brass, that can withstand the forces of the explosive charge when detonated and readily deform so as to provide desired plugging action.
  • a ductile material e.g. brass
  • An important feature of the invention is the employment of axial centering means for the plug. It has been found necessary to have a plug so centered within a tube in order to ensure even expansion and tight sealing of the tube end.
  • Such centering means could take various different forms that are not necessarily mere mechanical equivalents of one another.
  • one manner (not illustrated) of centering of the plug body could be to wrap tape around the body of the plug near each end thereof.
  • a preferred arrangement for centering the plugs is to use centering devices such as those illustrated. These are constructed of resilient material, such as spring steel, and take the form a spider 39 attached at the nose end of the plug and another spider 40 attached near the other end of the plug. It will be observed that the spiders 39 and 40 each have six legs 41 (see FIG. 3) and 42 (see FIG. 4) respectively. These legs extend radially and act to contact the walls of the tube and thus hold the plug body 38 'accurately centered within the tube prior to detonation thereof.
  • centering devices such as those illustrated. These are constructed of resilient material, such as spring steel, and take the form a spider 39 attached at the nose end of the plug and another spider 40 attached near the other end of the plug. It will be observed that the spiders 39 and 40 each have six legs 41 (see FIG. 3) and 42 (see FIG. 4) respectively. These legs extend radially and act to contact the walls of the tube and thus hold the plug body 38 'accurately centered within the tube prior to det
  • the spiders 39 and 40 may be attached to the plug 38 in any feasible or convenient manner but, as illustrated, the nose spider 39 is preferably attached by means of a machine screw 43 that fits closely through a central hole 45 of the spider 39 and thus holds the spider securely in a centralized manner at the nose end of the plug.
  • the spider 40 is attached at the other end of the plug body 38, e.g. by being fitted over a threaded hub 48 that is located extending coaxially from the plug body. This spider 40 may be held in place against axial displacement relative to the plug by means of a beveled nut 46.
  • an electrical connector 49 that is integrally constructed with the body of the plug and should be tightly sealed in place to withstand the explosion pressure without rupture.
  • the electrical circuit for an electrical detonator element (not shown) is completed by employing the body of cylinder 38 and the hub 48 as one electrically conducting current path, while the other path includes the connector 49.
  • any tool that would include some means for det-onating the plug after it was positioned within the tube sheet might be employed.
  • a preferred tool having a high degree of flexibility is one like that illustrated in FIGURE 2.
  • a socket 56 which has a flared and smooth sided portion nearest the open end thereof. Then there is a short threaded section of the socket which is adapted to engage the threads of the hub 48 and hold the plug 38 in place on the end of the head 50 of the insertion tool.
  • the other path for supplying electrical current to fire the plug detonator is carried from the connector 49 to an electrically conductive sleeve 60 that is supported for frictional contact with the connector by means of an insulating material insert 61. This maintains electrical separation from the first described path that includes the head 50.
  • the other electrical path is carried along the tool by another insulated wire 62 that has a bared end soldered to the sleeve 60, as indicated.
  • the cylindrical body 38 of the plug is constructed considerably longer than the thickness of the tube sheet 23, but the explosive charge arrangement within the plug is such that the expansion (by reason of the power charge) is concentrated near the nose end of the plug. Consequently, the expansion will take place largely within the thickness of the tube sheet which will easily withstand the expansive forces and thus help create the desired pressure proof plugging action.
  • a method according to this invention is applicable to structures such as heat exchangers, where a tube is attached at at least one end thereof to a tube sheet.
  • the steps of the method include:
  • the second step may be carried out in various ways. These need not be mechanically equivalent to one another, e.g. the plug might be inserted by placing same within a tube and then applying a fluid pressure behind the plug to cause it to move through the tube for a desired distance therein, or a string might be run through the tube in such a way that the plug could be pulled into the tube to the desired location.
  • a preferred manner of carrying out this step is that of pushing the plug through the tube, with a tool for providing such longitudinal pushing force, until the plug is located in the desired place prior to detonation.
  • the coaxial centering portion of this step may be carried out by employing various structures that are not necessarily mechanically equivalent to one another.
  • the plug might be placed in the tube and thereafter centered by inserting wedges as necessary.
  • Another manner of centering the plug might be to wrap a soft tape around the ends of the plug so that it will be held centered as it is placed within the tube.
  • a preferred manner of carrying out this part of the step is that of employing a pair of flexible spider means attached at the ends of the plug so that .these will physically hold the plug centered as it is pushed through the tube.
  • An expansible plug for use in heat exchanger tubes or the like comprising:
  • said body being constructed of ductile material having sufiicient wall thickness to avoid rupture when said charge is detonated
  • said radial centering means comprises a resilient centering device at each end of said plug body
  • said resilient centering devices have at least three radial protrusions extending more than the length of the inside radius of said tube from the axis thereof,
  • said centering devices comprise flat spider means constructed of spring steel, and further including means for coaxially attaching said spider means to said cylindrical body adjacent to the ends thereof.
  • spider means comprise thin stampings having six radial legs each, said legs being equally spaced apart circumferentially for accurate centering of the ends of said body.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Automatic Assembly (AREA)
  • Air Bags (AREA)
US609917A 1967-01-17 1967-01-17 Explosive type expansible plug Expired - Lifetime US3491798A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US60991767A 1967-01-17 1967-01-17

Publications (1)

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US3491798A true US3491798A (en) 1970-01-27

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US609917A Expired - Lifetime US3491798A (en) 1967-01-17 1967-01-17 Explosive type expansible plug

Country Status (5)

Country Link
US (1) US3491798A (de)
DE (1) DE1675398A1 (de)
FR (1) FR1551535A (de)
GB (1) GB1172962A (de)
NL (1) NL6800764A (de)

Cited By (8)

* 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
US3590877A (en) * 1968-09-20 1971-07-06 Babcock & Wilcox Co Explosive-activated plug
US3724062A (en) * 1971-03-18 1973-04-03 Westinghouse Electric Corp Explosively welded plug for leaky tubes of a heat exchanger and method of using the same
DE2210921A1 (de) * 1972-03-07 1973-09-20 Interatom Absperrvorrichtung fuer rohrleitungen mittels eines plastisch verformbaren dichtkoerpers
US3797098A (en) * 1972-09-14 1974-03-19 Nasa Totally confined explosive welding
US3890994A (en) * 1973-08-20 1975-06-24 Charles R Olsen Normally open valve construction having a deformable bladder
US4640192A (en) * 1985-11-19 1987-02-03 Nash Henry G Means for securing tubes to a tube sheet
US5479961A (en) * 1994-12-09 1996-01-02 Senior Engineering Company Method of plugging a heat exchanger tube and plug therefor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2744501C2 (de) * 1977-10-04 1984-02-23 Alfred Teves Gmbh, 6000 Frankfurt Anordnung zum Verschließen einer druckbeaufschlagbaren Bohrung

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1054810A (de) *
GB190418190A (en) * 1904-08-22 1904-09-29 Cornelius Middelthon Improvements in Means for Plugging or Stopping Cracked Fire Tubes in Steam Boilers.
US2779279A (en) * 1952-03-08 1957-01-29 Paul S Maiwurm Apparatus for securing a tube or tubes in a body member
US3175618A (en) * 1961-11-06 1965-03-30 Pan American Petroleum Corp Apparatus for placing a liner in a vessel
US3203479A (en) * 1963-06-04 1965-08-31 Warren Petroleum Corp Condenser tube plug
US3364562A (en) * 1962-11-08 1968-01-23 North American Aviation Inc Method of making a butt joint by explosive welding

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1054810A (de) *
GB190418190A (en) * 1904-08-22 1904-09-29 Cornelius Middelthon Improvements in Means for Plugging or Stopping Cracked Fire Tubes in Steam Boilers.
US2779279A (en) * 1952-03-08 1957-01-29 Paul S Maiwurm Apparatus for securing a tube or tubes in a body member
US3175618A (en) * 1961-11-06 1965-03-30 Pan American Petroleum Corp Apparatus for placing a liner in a vessel
US3364562A (en) * 1962-11-08 1968-01-23 North American Aviation Inc Method of making a butt joint by explosive welding
US3203479A (en) * 1963-06-04 1965-08-31 Warren Petroleum Corp Condenser tube plug

Cited By (8)

* 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
US3590877A (en) * 1968-09-20 1971-07-06 Babcock & Wilcox Co Explosive-activated plug
US3724062A (en) * 1971-03-18 1973-04-03 Westinghouse Electric Corp Explosively welded plug for leaky tubes of a heat exchanger and method of using the same
DE2210921A1 (de) * 1972-03-07 1973-09-20 Interatom Absperrvorrichtung fuer rohrleitungen mittels eines plastisch verformbaren dichtkoerpers
US3797098A (en) * 1972-09-14 1974-03-19 Nasa Totally confined explosive welding
US3890994A (en) * 1973-08-20 1975-06-24 Charles R Olsen Normally open valve construction having a deformable bladder
US4640192A (en) * 1985-11-19 1987-02-03 Nash Henry G Means for securing tubes to a tube sheet
US5479961A (en) * 1994-12-09 1996-01-02 Senior Engineering Company Method of plugging a heat exchanger tube and plug therefor

Also Published As

Publication number Publication date
NL6800764A (de) 1968-07-18
DE1675398A1 (de) 1971-01-21
GB1172962A (en) 1969-12-03
FR1551535A (de) 1968-12-27

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