US3831413A

US3831413A - Tube expander

Info

Publication number: US3831413A
Application number: US00302951A
Authority: US
Inventors: R Glatthorn
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1972-11-01
Filing date: 1972-11-01
Publication date: 1974-08-27
Anticipated expiration: 1991-08-27
Also published as: JPS4977874A; FR2220326A1; FR2220326B1; ES420128A1; SE404306B; JPS5123466B2

Abstract

A tube expander comprising an elastomer bushing which expands outwardly when compressed between two bushings pulled together by a cable, which is pulled through a plurality of short lengths of tubing capable of folding against each other when the cable is slack, allows the tube expander to fit through manways and into corners of channel heads of heat exchangers to expand the tubes a predetermined distance from one end thereof.

Description

United States Patent 1 91. 1111 3,831,413 Glatthorn Aug. 27, 1974 [54] TUBE EXPANDER 3,691,609 9/1972 lce, Jr. et al 29/252 Inventor: Raymond E a m, FOREIGN PATENTS OR APPLICATIONS Petersburg, 1,199,258 6/1959 France 29/505 [73] Assignee: Westinghouse Electric Corporation,

. Pittsburgh, Pa. Primary Examiner-Richard J. Herbst Nov. 1 Attorney, Agent, OI FirmF. Baehl', Jr.

[21] Appl. No.: 302,951 [57] ABSTRACT A tube expander comprising an elastomer bushing (g1. 725;},3925/(2); which expands outwardly when compressed between [58] Fieid 62 370 two bushings pulled together by a cable, which is pulled through a plurality of short lengths of tubing 72/466 29/523 269/48'1 capable of folding against each other when the cable is [56] References Cited slack, allows the tube expander to fit through manways and into corners of channel heads of heat ex- UNITED STATES PATENTS changers to expand the tubes a predetermined disl,0l6,770 2/1912 Persons tance from one end thereof, 2,507,979 5/1950 Kelar 3,252,210 5/1966 Bowden 8 Claim, 3 Drawing Figures TUBE EXPANDER BACKGROUND OF THE INVENTION This invention relates to tube expanders and more particularly to tube expanders which expand a tube a predetermined distance behind the tube sheet. In heat exchangers, such as nuclear steam generators in which the tubes are U-shaped, when a tube fails it is very difficult to remove the whole tube, however, it is desirable to take out a section of the tube for metallurgical examination. Before removing the section of the tube it is desirable to expand the tube adjacent one of the tube support sheets, to generally hold the tube in its normal position when one or both of the end portions are removed for inspection.

The expanding tool must be capable of being fed through a manway and around a small radius so that it can fit in close quarters in the channel head of the heat exchanger and must be able to be operable in a minimum amount of time when the heat exchanger is a nuclear steam generator as these vessels generally have a low level of radioactivity.

SUMMARY OF THE INVENTION Apparatus for expanding a tube a predetermined length from one end thereof when made in accordance with this invention, comprises a cable, a bushing attached to the cable, an elastomer tubular member slidably disposed over the cable, and a device for drawing the cable through the tubular members, whereby the elastomer tubular member is compressed and expands in a radially outward direction thereby expanding a portion of the tube adjacent thereto.

BRIEF DESCRIPTION OF THE DRAWINGS The objects and advantages of this invention will'become more apparent from reading the following detailed description in connection with the accompanying drawings, in which;

FIG. 1 is a perspective view of a tube expander made in accordance with this invention;

FIG. 2 is a partial perspective view showing how the tube expander folds to fit into clamped quarters; and

FIG. 3 is a partial elevational view of heat exchanger having a tube expander disposed to expand a tube adjacent a tube support sheet.

Corresponding reference characters indicate corresponding parts throughout the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail, FIG. 1 shows an apparatus 1 for expanding a tube a predetermined distance from one end thereof. The apparatus or tube expander 1 comprises a wire rope or cable 3, a first bushing 5 fastened to one end of the cable 3 by soldering or other means, and an elastomer tubular member 7 made of polyurethane or other resilient material, slidably disposed on the cable 3 adjacent the first bushing 5. A second bushing 9 is slidably disposed on the cable 3 adjacent the elastomer tubular member 7 and a plurality of tubular members or pipes 11 are slidably disposed on the cable 3.

The bushings 5 and 9 generally have two cylindrical surfaces, a short portion 12 adjacent the elastomer tube member 7 which is slightly larger in diameterthan the elastomer tube member 7 and slightly smaller in diameter than the inside diameter of the tube to be expanded. Thus, preventing the elastomer from flowing into the clearance between the bushing and the tube to prevent damage to the elastomer as it is compressed between the bushings.

The tube expander 1 also comprises means for drawing the cables 3 through the tubular members 7 and 11. The means for drawing the cable 3 through the tubular members comprises a base or bucking plate 13, a pair of hydraulic cylinders 15 fastened to the base plate 13, and a bridge plate 17 also fastened to the hydraulic cylinders 15. The bridge plate 17 has a semi-circular grooved cable support 19 cooperatively associated therewith.

The cable 3 loops over the cable support 19 andis tied to itself by a cable clamp 21. The base plate 13 has a centrally disposed hole 23 through which the cable is threaded.

A hydraulic pump 25 which may be hand operated, as shown, or motor operated, supplies pressurized hydraulic fluid to the cylinders 15, which expand as pressurized fluid is supplied thereto, drawing the cable 3 through the tubular members 7 and 11 and causing the bushings 5 and 9 to axially compress the elastomer tube member 7 which expands radially outwardly to expand the tube.

As shown in FIG. 2, the tubular members 7 and 11 and bushings 5 and 9 fold with respect to each other when the hydraulic cylinders 15 are not extended allowing the apparatus to fit through a manway and into a tube of heat exchanger even though there may be lim-' ited access to the tube as it may be adjacent the wall of a spherical shaped channel head.

As shown in FIG. 3, the operation of the tube expander 1 is as follows; a predetermined number of tubular members 11 are threaded on the cable 3 and the cable is threaded through the hole 23 in the base plate 13 and looped over the cable support 19 and clamped to itself by the cable clamp 21 securing the end of the cable to the cable support. Sufficient slack is provided in the cable so that the tubular members and bushings can fold with respect to each other as shown in FIG. 2. The number and length of the tubular members is determined by the distance from the end of a tube 31 to a support sheet 35 or a distance from a tube sheet 33 to a support sheet 35, so as to position the elastomer bushing adjacent the location where the tube is to be expanded. The tube expander 1 is fed through a manway (not shown) and the end containing the elastomer member 7 is fed in to the tube 31. When the base plate 13 abuts the tube sheet 33 the hydraulic pump 25 is operated supplying pressurized fluid to the cylinders 15 causing the cylinders to expand moving the bridge plate 17 away from the support plate 13 and drawing the cable 3 through the tubular members which result in the bushings 5 and 9 compressing the elastomer tubular member 7 in an axial direction, which causes the clastomer tubular member 7 to expand radially thereby contacting the tube 31 and expanding it radially outwardly into engagement with the tube support sheet 35, so that a portion of the tube 31 can be cut off and extracted for metallurgical tests and the portion of the tube remaining in the heat exchanger will be securely fastened in its normal position. Thus, preventingthe cut off tube from contacting adjacent tubes and damaging them, as the cut off tube vibrates as a result of fluid flow or vibrations induced by associated equipment.

Since the tubular members can fold, the tube expander is operable in cramped quarters and no time is required for assembly in place, the tube expander can be assembled in the shop to expand a tube a predetermined distance from the end thereof and a minimum amount of time is required in utilizing the tube expander 1. This is extremely important when the heat exchanger is radioactive and the time an operator can spend therein is limited.

What is claimed is:

1. Apparatus for expanding a heat exchanger tube a greater distance from one end thereof than the clearance between the one end of the tube and an adjacent wall of the heat exchanger, said apparatus comprising a cable, a tubular bushing member attached to the cable, an elastomer tubular member slidably disposed over said cable, a plurality of rigid segmented tubular members slidably disposed over said cable, all of said tubular members being cooperatively associated with the cable to allow each tubular member to fold with respect to the adjacent tubular member, and means for drawing the cable through said tubular members, said elastomer tubular member being so disposed with respect to the other tubular members that when the cable is drawn through the tubular members said elastomer tubular member is compressed in an axial direction causing it to expand in a radially outward direction, thereby expanding a portion of said tube adjacent thereto.

2. Apparatus as set forth in claim 1 and further comprising a second tubular bushing member slidably disposed over the cable, each bushing having a cylindrical surface slightly smaller in diameter than the tube and slightly larger in diameter than the elastomer tubular member.

3. An apparatus as set forth in claim 2, wherein the cylindrical surface on the first mentioned bushing is adjacent the elastomer tubular member and the cylindrical surface on the second mentioned bushing is also adjacent the elastomer tubular member.

4. An apparatus as set forth in claim 2, wherein the bushing has an additional cylindrical surface smaller in diameter than said first mentioned cylindrical surface.

5. Apparatus as set forth in claim 2, wherein cylindrical surface of the bushing is slightly larger in diameter than the elastomer tubular member.

6. Apparatus as set forth in claim 1, wherein the means for drawing said cable through said tubular members comprises at least one hydraulic cylinder disposed to draw said cables through said tubular members as said hydraulic cylinder is expanded.

7. Apparatus as set forth in claim 1, wherein the means for drawing said cable through said tubular members comprises a pair of hydraulic cylinders cooperatively associated to draw said cable through the tubular members as said cylinders are extended.

8. Apparatus as set forth in claim 1, wherein the elastomer tubular member is made of polyurethane.