US2856963A

US2856963A - Tube plugging device

Info

Publication number: US2856963A
Application number: US666658A
Authority: US
Inventors: John J Hoerter
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1957-06-19
Filing date: 1957-06-19
Publication date: 1958-10-21
Anticipated expiration: 1975-10-21

Description

Oct. 21, 19 58 J. J, HHHHH ER 2,856,963

Filed June 19, 1957 TUBE PLUGGING DEVICE John J. Hoerter, Chatham, N. 3., assignor to Esso Research and Engineering Company, a corporation of Delaware Application June 19, 1957, Serial No. 666,658 4 Claims. (31. 138-89) This invention relates to a tube plugging device for apparatus containing a number of tubes arranged in inaccessible'places and/or .tubes arranged in parallel relationbetween headers where it is desired to plug a leaking tube without dismantling the entire apparatus.

More particularly this invention is especially adapted for plugging leaking tubes of tubular heat exchangers, boilers and the like, to take such leaky tubes out of service without dismantling the entire heat exchanger. With the present invention the time and labor required to plug a leaky tube is greatly reduced. The device of the present invention is useful for plugging a leaky exchanger, condenser or cooler tube in a bundle when only a few tubes are leaking so that the heat exchanger apparatus can continue in use without the necessity of immediately retubing the tube bundle 'or being replaced by a new heat exchanger.

At the present time one .of the practices in the industry is to remove the channel cover of a heat exchanger unit adjacent the channel section and stationarytube sheet. This exposes the tube ends in the stationary tube sheet of the tube bundle. Hydrostatic pressure, using a fluid medium such as water or oil is then applied to the shell side of the exchanger assembly, whichis the space between the outside of the tubes and the outer shell of the exchanger. The leaky tube can then be detected by the fluid or liquid running out of the exposed end of the leaky tube or tubes. a

When it has been established which tubes are leaking, the hydrostatic pressure is removed and the shell cover and floating tube sheet cover at the other end of the exchanger unit are removed to expose the opposite end of the tube' bundle. Plugs are then driven into each end of the leaking tube or tubes to plug them. The shell cover and floating head or tube sheet cover are then replaced and a test is again applied It further leakage is noted, the entire operation is repeated again and again until such time as all the leaking tubes in the bundle are plugged.

With the device of the present invention, the leaky tubes can be plugged without removing the shell cover or floating head oritube sheet cover. When the hydrostatic pressure test indicates the leaking tube or tubes, the tube or tubes. can 'be plugged from the channel end immediately. The repair is permanent and the exchanger, cooler or condenser can be returned to service. This type of repair saves time and money.

The need for plugging tubes arises frequently in plant operations. With the device of the present invention the time. and labor required to test and plug leaky heat exchanger tubes or the like are greatly reduced.

Briefly, the specific form of the invention disclosed includes a rod or a cable having a threaded stud at one end. A collar having a tapered surface is slidably mounted on the stud. A sleeve is arranged between the collar and a plug member having a weakened section comprising a V-shaped groove. One end of the plug member has a smaller cylindrical portion received by said nitecl States PatentO 2,856,963 Patented Oct. 21, 1958 threaded stud. The other and larger end of the plug member has'a tapered surface. It is separated from the small cylindrical section by a V-shaped groove comprising a weakened section. The sleeve has spring clips at one end which compress to fit through the tube when the rod or cable is moved inwardly. The sleeve is pushed entirely through the tube and then pulled back which allows the spring-clips to expand and engage the far inaccessible end of the leaky tube. The plug member wedges the sleeve against the inside wall of the tube when the rod or 'cable is further withdrawn. The pull on the rod or cable is increased until the plug breaks at the weakened section leaving the tapered plug tightly wedged in the sleeve. The rod or cable and collar are removed and may be reused.

In the drawing:

Fig. 1 represents a longitudinal cross section of a tube and a plugging device made according to this invention inside thereof with parts broken away to reduce the length of the tube in the drawing;

Fig. 2 represents an exploded view of the tube plugging device of the present invention; and

Fig. 3 represents a longitudinal cross section of the one end of a tube with the plugging member in place and broken .away from the actuating rod or cable.

Referring now to the drawing, the reference character 10 designates a tube to be plugged. The tube 10 is held between tube sheets 12 and 14 of which only a part is shown. The tube is broken away to allow showing of the entire device. The drawing only shows one tube but it is to be understood that in a tubular heat exchanger or the like a large number of tubes are held in parallel relation between the tube sheets 12 and 14.

In a preliminary examination of the heat exchanger or bundle of tubes it has been found that tube 10 had a leak in it and had to be plugged at both ends to prevent contamination of the material being cooled or heated. With the present invention it is only necessary to remove the channel cover of the heat exchanger at the end adjacent header 12. The plugging device of the present invention is used to plug the far end of the tube 10 or the end near header 14 where the cover on the other end of the heat exchanger has not been removed.

The plugging device includes a rod or cable 16 having an enlarged head 18 or handle or the like for manipulating and pulling the cable or rod 16 when the plugging device is to be used to plug one end of the tube 10. The rod or cable 16 is longer than the length of the tube 10 to permit operation of the device as will be described hereinafter in greater detail. 7

The inner end of rod or cable 16 is provided with an integral threaded stud 22 extending therefrom. The stud 22 has a smaller diameter than the rod or cable 16. As

shown in Fig. 1 stud 22 is screwed into threaded open ing or socket 24 .in a relatively small cylindrical end portion 26 of plug member 28. The cylindrical portion 26 is shown as about the same diameter as the rod '16 and is connected to or formed integrally with a larger tapered solid section 32 to form the plug member 28. The cylindrical portion 26 and larger tapered section 32 are connected by a weakened section formed by a sharp V-shaped groove 34 which reduces the diameter or plug member 28 at this point below that of the cylindrical section or end 26. The depth of the groove is based on the tensile strength of the material so that sufiicient force may be exerted to pull the plug tight before the break H at the ou er end 36 where the diameter of the plug mem- 3 her 28 is slightly less than the interior diameter of the tube 10.

Arranged between the small cylindrical end 26 of plug member 23 and'the inner end of rod 16 is a tapered collar '38 having a central opening 42 to receive stud 22 and to be rotatably mounted thereon. The smaller end of the tapered collar 38 has a diameter about the same as the diameter rod 16 and abuts the shoulder 44 on rod 16. The collar 38 has anouter surface 46 which tapers or flares outwardly to form a larger base portion 48.

The base portion of the tapered collar rests against one end of sleeve 52 which has an outside diameter slightly smaller than the inside diameter of the tube 113 to be plugged. The sleeve 52 has a wall which tapers from a thicker Wall portion 53 atone end adjacentthe flared bottom 48 of collar :38 to a thinner wall portion at the other end toward the right in Fig. 1. As shown in Fig. l the sleeve 52 abuts the flared bottom 48 of collar 38 and extends to the right about to the middle of tapered plug portion 32.

The end of the sleeve 52 having the thinner wall portion is slotted or serrated .as shown at 54 in Fig. 2 and provided with spring members 56 having curved clip members 58 at the ends thereof. The taper and size of the plug portion 3?. conforms generallyto the taper andsize of the sleeve '52 which in turn depends on the size of the tube 1%. Spring members 56 have their outer ends 58 curled back to form catch members for the end of the tube 10 as shown in Fig. 3 and as will be described in greater detail hereinafter. As shown in Fig. 1 the spring members 56 are bent down by contact with the inner wall of tube 19 because the spring members 56 are of a greater diameter than the inside of the tube 10.

The dimensions of the tube plugging device are dependent of the size of the tube to be plugged and different sizes of the plugging device are used for dilferent sized pipes or tubes. As one form of the invention, a specific example will be given in connection with one size tube. A five-eighths inch outside diameter number 11 B. W. G. (Birmingham wire gauge) tube will be used as the tube 10. With this tube the steel rod or cable 16 used to insert the plug into the tube 16 will have a three-eighths inch outside diameter and will be approximately 2i) feet long to accommodate tubes to a length of about 18 feet. Where longer tubes are to be worked on, the cable or rod 16 must be longer.

The end of the rod or cable 16 is provided with a three-sixteenths inch threadedstud 22 of tempered steel 1 /2 inches long. The rod or cable 16 of the size described will be suitable for plugging tubes from A; to 1 /2 inches outside diameter which are the sizes most frequently used. The tapered collar 38 is slidably mounted on the stud 22. The smaller end of the collar 33 abutting shoulder 44 on rod 16 has a diameter about the same as the rod 1. The larger and 48 of the tapered collar 38 is slightly smaller than the diameter of the sleeve 52 of the plugging device. This means that a collar of a different size will be needed for each size tube to be plugged but the colfilar is reclaimed each time so that a set of collars will last indefinitely. The purpose of the tapered collar 38 is to permit pushing the plugging device completely through the tube It to the right in Fig. l and then the collar 38 guides the plugging device back into the tube end adjacent tube sheet 14 as the cable or rod 16 is pulled back to the left in Fig. l.

The sleeve 52 has an outside diameter slightly smaller than the inside diameter of the tube 16 to be plugged. The inside of the sleeve 52 is tapered from a wall thickness of about one-sixteenth inch at the base or lower lefthand portion 53 as shown in Fig. l for a five-eighths inch tube to a thinner wall at the other end terminating in the slotted portion 54. Where a larger sized tube it) is to be worked on, the thickness of the end 53 of sleeve 52 will begrcater. The thickness of the thin tapered wall adjacent the slotted or serrated portion 56 is approximately one-thirty-second inch.

The curved spring members 56 are flared outwardly so that when the sleeve 52 is pushed through the end of the tube adjacent tube sheet 14, and then pulled back to the left in Fig. 1, the curved spring members 58 on the clip members 56 will grip or engage the end of the tube as shown in Fig. 3 and hold the sleeve 52 in position at the end of the tube.

The tapered solid section 32 of plug member 28 is about three-fourths of an inch long and tapered to conform to the inner wall of the sleeve 52. The tapered plug member 32 extending from the V-shaped groove 34 to the larger end 36 has a smaller diameter adjacent the top of the V-shaped groove 34 of about one-fourth inch and a larger diameter at end 36 of three-eighths inch. The cylindrical section or portion 26 of plug member 28 has a diameter of about one-fourth inch. The bottom of the V-shaped groove 34 has a diameter of about five-thirty-seconds inch. The entire plug member 28 is made of brass in the example given but steel, Monel, copper, plastic or any other suitable material may be used. The V-shaped groove 34 weakens the plug member 28 at this point so that upon applying force and pulling the rod 16 to the left in Fig. 1, the cylindrical section 26 of the plug member 28 snaps 01f at the V-shaped groove 34 as shown at 62 in Fig. 3.

The operation of the device will now be given. When it is determined that a tube such as tube 10 needs to be plugged in a tube bundle or heat exchanger, one cover of the heat exchanger is removed and the plugging device as shown in Fig. 1 is inserted in the tube and pushed to the right in Fig. 1 completely through the tube so that the entire assembly beyond collar 38 projects beyond the end of tube 10. Then the rod 16 is pulled to the left and the tapered surface of the collar 38 guides the plugging device back into the tube 10 adjacent tube sheet 14. The rod 16 is then pulled back until the clip members 58 on spring members 56 engage the end of the tube 10 as shown in Fig. 3. With the sleeve in this position further pulling to the left on the rod 16, results in the tapered plug portion 32 of the plug member 28 entering the sleeve 52 like awedge and as the sleeve 52 is held in stationary position by the spring clip members 38 the only movement is between the tapered plug and the sleeve member 52. The pull on the cable or rod 16 is continued until the cylindrical section 26 of the plug member 28 snaps off at the V- shaped groove 34 as shown at 62 in Fig. 3. When this occurs, the plug member 28 has been pulled tightly into the sleeve 52 expanding the sleeve 52 to seal the end of the tube 10. As shown in Fig. 1 the 'plug member 28 is a solid member.

The rod 16 is then withdrawn from the tube and a solid plug driven into the exposed open end of the tube 10 adjacent tube sheet 12 with a hammer. The broken cylindrical section 26 is removed from the threaded stud 22 and the rod 16 and stud 22 and collar 38 can be used over again with another plug assembly.

:While one type of metal has been described as useful for the manufacture of the entire plug member 28,.i't is to be understood that other metals or materials may be used, the only requirement being that the material or metal may be broken away at the V-shaped groove 34 by asserting a pulling force on the rod 16.

Whatis claimed is:

1. A device of the character described adapted to be.used inplugging a tube in a tube bundle or the like which includes an elongated actuating rod member, a plug member of a size slightly smaller than the internal diameter of the tube to be plugged, said .plug member having a tapered or flared body portion, thesmaller end of said plug member being connected .with a smaller diameter cylindrical section, the connecting portion between said cylindrical section and said smaller end of said plug member having a smaller diameter than said cylindrical portion to form a weakened section of said plug member, a sleeve of substantially the same diameter as the tube and having a tapered wall to complement the tapered portion of said plug member and having spring clip members at the end adjacent the thinner wall, and surrounding a portion of said plug member, said rod member having a threaded stud extending therefrom and received in a threaded socket in said cylindrical section, a tapered collar mounted on said stud between said rod member and the end of said sleeve adjacent the thicker wall thereof, whereby on pushing the device entirely through the tube and pulling back on said rod member, the tapered collar guides the plug member back into the tube, said spring members engage the end of the tube and said plug member is forced into said sleeve to wedge said sleeve against the inner wall of the tube and further pulling on said rod member breaks said plug member at said weakened section to leave a solid plug in the end of the tube.

2. A device of the character described adapted for use in plugging a tube in inaccessible places which includes an elongated rod member, a plug member having a solid tapered body portion with the largest diameter being slightly smaller than the diameter of the tube, means for rigidly securing said plug member to said rod member, said plug member having a weakened portion intermediate its ends, a sleeve member surrounding a portion of said plug member and having a wall tapering in thickness from one to the other to complement the contour of said plug member, said sleeve member having spring clip means adjacent the end of thinner wall thickness, collar means between said rod member and said plug member for abutting the end of said sleeve member adjacent the thickened wall portion there of, whereby on pushing the device entirely through the tube and then pulling back on the rod member, said spring means will engage the end of the tube, the tapered plug portion will wedge said sleeve in the tube and the plug member will break at said weakened portion leaving a solid plug in the end of the tube.

3. A device of the character described including a plug member having a tapered portion, a sleeve having 6 a tapered inner Wall adapted to fit over said tapered portion of said plug member, said sleeve having spring clip members at one end, said plug member having a smaller diameter cylindrical portion attached to said tapered portion of said plug member by a weakened portion, an actuating elongated member, means for securing one end of said elongated member to said cylindrical portion of said plug member, and means for normally abutting the thickened end portion of said sleeve arranged on said plug member whereby upon use said I the end of the tube.

4. A device of the character described including a solid plug member having a frusto-conical portion at one end portion and a smaller cylindrical portion at the other end portion, said frusto-conical and cylindrical portions being rigidly connected by a thinner weakened section, a sleeve having a tapered inner wall thicker at one end than the other, said sleeve being adapted to fit over and tightly engage the surface of said frusto-conical portion of said plug member when said plug member is in final position, an elongated actuating rod having a smaller diameter stud extending therefrom and secured to said cylindrical portion of said plug member, a collar arranged about said stud and held between said rod and the thickened end portion of said sleeve, said sleeve at thethin wall end having springy clip members for engaging the end of a tubular member whereby said sleeve is wedged against the inner wall of the tubular member by said frusto-conical plug portion by force exerted on said rod and the plug is broken at said weakened portion.

References (Iited in the file of this patent UNITED STATES PATENTS 1,657,751 Henderson Jan. 31, 1928 2,416,829 Hartley Mar. 4, 1947 FOREIGN PATENTS v 9,047 Great Britain Apr. 18, 1902