GB2155381A - A tube welding torch assembly - Google Patents

Abstract

Apparatus for supporting a welding torch 7 to face weld a tube 5 end to a tube plate 4 of, for example a condensor or heat exchanger has a locating sleeve 6 within which the stem of a welding torch is slidably housed. The locating sleeve 6 is slidably carried by a support structure 2 which is stationarily mounted relative to the tube during a welding operation. The support structure includes a device for securing the welding torch in position relative to the tube and tube plate for welding purposes while permitting withdrawal of the locating sleeve along the welding torch from the tube so as not to interfere with the welding operation. The structure is held in position by an expanding bolt 21 in an adjacent welded pipe 5. The welding torch is first positioned and then clamped by a set-screw passing through hole 37. The sleeve 6 is then withdrawn to allow welding using electrode 41. Shielding gas may be provided. <IMAGE>

Description

SPECIFICATION A tube welding torch assembly The present invention relates to apparatus for supporting a welding torch and, relates especially to apparatus for supporting a tube welding torch for face welding tube ends to tube plates as is required in, for example, the construction of condensers and heat exchangers.

It is an object of the present invention to provide a supporting apparatus which permits easy but precise location of a welding torch relative to the end of a tube and a tube plate to be welded together.

According to the present invention there is provided apparatus for supporting a welding torch to face weld a tube end to a tube plate of, for example, a condenser or heat exchanger, the apparatus comprising a locating sleeve adapted slidably to house the welding torch and being slidably receivable within the tube, and a support structure within which the locating sleeve is slidably carried and adapted to be stationarily mounted relative to the tube during a welding operation, and including a device adapted to secure the welding torch in position relative to the tube and tube plate for welding purposes while permitting withdrawal of the locating sleeve from the tube.

Also according to the present invention there is provided an assembly of a supporting apparatus as defined in the immediately preceding paragraph and a welding torch.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of one embodiment of a welding torch assembly including the present invention and mounted, ready for use, to the end of a condenser tube; Figure 2 is a detailed plan view of the mounting flange of the welding torch of Figure 1; Figure 3 is a detailed view of the locating sleeve of the welding torch of Figure 1; and Figure 4 is a fragmentary cross-sectional view corresponding to Figure 1 of another embodiment of a welding torch assembly including the present invention.

Referring to Figures 1 to 3 of the accompanying drawings there is shown a standard fusion welding torch 1, positioned by means of a supporting apparatus 2 in the end of a condenser tube 3 which is to be faced welded to a tube plate 4. It will be noted that in the section of tube plate 4 shown in Figure 1 there are shown two other condenser tubes 5 already welded in position.

The supporting apparatus 2 comprises a locating sleeve 6 in which a stem 7 of the welding torch 1 is slidably received.

The locating sleeve 6 has an external diameter substantially the same as the internal diameter of the tube 3 and its end to be inserted into the tube 3 is tapered as indicated at 8 to facilitate initial positioning of the sleeve 6 in the tube 3.

The locating sleeve 6 is axially slotted as indicated at 9 at its tapered end 8 for a purpose to be referred to later.

At its other end the locating sleeve 6 has a head 10 of larger diameter than the sleeve 6, which head 10 is formed with diametrically-opposed screw threaded holes 11 adapted to receive a handle 12 to facilitate sliding movement of the locating sleeve 6 along the welding torch stem 7.

The locating sleeve 6 is circumferentially grooved externally at 13 and internally at 14 to receive O-ring seals 15 and 16 respectively.

The locating sleeve 6 is slidably disposed within a support bush 17 which, in use (see Figure 1), abuts the tube plate 4 and, in initially locating the welding torch stem 7, is abutted by the head 10 of the locating sleeve 6.

The support bush 17 has an external shoulder 18 and is of increased internal diameter as indicated at 19 at its tube plate abutting end, i.e. at the axial slot 9 of the locating sleeve 6 during said initial location.

The support bush 17 is in turn slidably carried by a mounting flange 19 which has a bore 20 through which the support bush 17 extends, the shoulder 18 of the latter butting the mounting flange 19.

The mounting flange 19 is secured or locked relative to the tube plate 4 by expandible bolt arrangements (only one shown) generally indicated at 21. It is to be noted that, as a result, the support bush 17 is trapped or immobilised between the tube plate 4 and the mounting flange 19.

Provision is made in the mounting flange 19 for three such expandible bolt arrangements 21 at the locations 22 angularly equi-spaced from one another and uniformly spaced from the bore 20.

One or more expandible bolt arrangements 21 may be used to secure the mounting flange 19 relative to the tube plate 4. Preferably two are used.

Each expandible bolt arrangement 21 comprises a sleeve 23 axially slotted at 24 within which a bolt 25 with a wedging end 26 is received, a peg 27 mounted on the bolt 25 engaging in the slot 24.

The bolt 25 is of reduced diameter at the mounting flange end and is screw-threaded to receive a nut 28. Tightening of the nut 28 axially draws, as is known, the wedging end 26 into the sleeve 23 to lock same against the internal wall surface of the tube 5 thus locking the mounting flange 19 relative to the tube plate 4.

A second support bush 29 is provided in alignment with the support bush 17 and spaced outboard of support bush 17, which support bush 29 is flanged as indicated at 30 and is formed with three holes 31 aligned with three holes 32 in the mounting flange 19.

The mounting flange 19 and support bush 29 are interconnected by three pillars 33 secured in position by headed bolts 34, 35 respectively passing through holes 31 and 32.

The support bush 29 has an internal split clamping sleeve 36 surrounding the stem 7 of the welding torch and which is used to secure the stem 7 of the welding torch when the latter is set in precise welding position, the sleeve 36 being immobilised by a set screw (not shown) passing through a ra dial screw-threaded hole 37 in the support bush 29.

A sleeve 38 screw-engages the support bush 29 as indicated at 39 and incorporates a lock nut 40, the sleeve 38 acting as a bearing to support the welding torch stem 7 and permit axial movement thereof. The lock nut 40 serves to secure the sleeve 38 correctly within the support bush 29.

The sleeve 38 positions the welding torch stem 7 axially correctly and precisely to position an electrode 41 at the other end of the stem 7 relative to the end of the tube 3 and the tube plate 4.

The welding torch stem 7 is provided at the outer end with a screw arrangement 42 for coupling to the welding torch stem a welding torch head (not shown).

It is to be noted that the gas seals 15 and 16 respectively lie between the locating sleeve 6 and the support bush 17 and the welding torch stem 7 and the locating sleeve 6.

It is to be noted also that the electrode 42 lies within the axial slot 9 which is, as can be seen, open to the end of the locating sleeve 6.

In use, the complete welding torch and support assembly is positioned against the tube plate 4 with the locating sleeve 6 roughly aligned with the end of the condensor tube 3 to be welded. Using the handles 12 the locating sleeve 6 is then pushed forward so that the end thereof enters the condensor tube 3 and the welding torch stem 7 is centralised therein. In this position the expandible bolts 23 to 27 are located in adjacent condensor tubes 5 and locked into position, whereupon the nuts 28 are tightened to secure the support bush 13 in position against the tube plate 4 and to ensure that the complete assembly is held in position. Using the handles 12 the locating sleeve 6 is then fully retracted to expose the electrode 42 and the weld cycle is effected. After completion of the weld cycle the assembly can be released and repositioned on the next hole to be welded.

Reference is now made to Figure 4 and it is to be noted that like parts to those of Figures 1 to 3 are referred to by the same references with the suffix A save for the reference 17A which in Figure 4 is designated 17A1.

The outer support bush arrangement 29 to 40 has been omitted since it corresponds with the arrangement illustrated in Figure 1.

In Figure 4 the mounting flange 50 is substantially the same as mounting flange 19 with a central bore, holes 22A equivalent to holes 22, and holes (not shown) equivalent to holes 32 for the connecting pillars 20A. It has, however, a central bush configuration 51 to provide an axial support for the inner support bush 17A. Like the supporting flange 19 of the Figures 1 to 3 embodiment it has a screw-threaded bore diametrically disposed relative to its bore 20A to receive a grub screw (not shown) for securing the support bush 17A relative to the mounting flange 50.

One or more cam clamp arrangements 52 are provided at locations 22A to secure the mounting flange 50 relative to the tube plate 4A. Preferably two are used.

Each cam clamp arrangement 52 comprises a clamping sleeve 53 axially slotted at 54 within which a clamping rod 55 with a wedging head 56 is received. The clamping rod 55 is flattened at its wedging head remote end and a cam 57 with an integral handle 58 is secured to said flattened end by a pin 59.

A distance piece 60, say, of brass surrounds the clamping rod 55 at the side of the mounting flange 50 remote from the tube plate 4A. This distance piece 60 abuts against the mounting flange 50 and provides a bearing surface for the cam 57.

It will be manifest that if the handle 58 is pushed in the direction of the arrow A, the cam 57 will react against the distance piece 60 so as to pull the clamping rod 55 through the axially-split clamping sleeve 53 and the wedging head 56 consequently expands the clamping sleeve 53 tightly against the wall of the tube 5A thus locking the mounting flange 50 relative to the tube plate 4A.

Release is effected by a reverse movement of the handle 58.

In order to avoid oxidation of the weld inert gas is supplied to the site of the weld through the stem of the welding torch.

Claims (19)

1. Apparatus for supporting a welding torch to face weld a tube end to a tube plate of, for example, a condenser or heat exchanger, the apparatus comprising a locating sleeve adapted slidably to house the welding torch and being slidably receivable within the tube, and a support structure within which the locating sleeve is slidably carried and adapted to be stationarily mounted relative to the tube during a welding operation, and including a device adapted to secure the welding torch in position relative to the tube and tube plate for welding purposes while permitting withdrawal of the locating sleeve from the tube.

2. Apparatus as claimed in claim 1 in which the locating sleeve is tapered at its end adapted for insertion into the tube to facilitate such insertion.

3. Apparatus as claimed in claim 2 in which the locating sleeve at its tube remote end is formed with a head adapted detachably to receive a handle for use in sliding the locating sleeve relative to the welding torch and the support structure.

4. Apparatus as claimed in claim 2 or 3 in which the locating sleeve is axially slotted for part of its length from its tube-insertible end to permit an electrode of the welding torch to access the tube end and the tube plate.

5. Apparatus as claimed in claim 3 or 4 in which the support structure comprises a support bush within which the locating sleeve is slidably received, the support bush being adapted to abut the tube plate and the head of the locating sleeve.

6. Apparatus as claimed in claim 5, in which the support bush is slidably supported in a mounting flange which abuts a shoulder of the support bush, there being means for securing the mounting flange in position relative to the tube plate.

7. Apparatus as claimed in claim 6, in which the mounting flange securing means comprises an ex pandible sleeve insertible within a tube already welded to the tube plate, and a rod with a wedging head located within the expandible sleeve for axial movement through the latter to tighten same against the wall of the tube, the rod being operatively associated with the mounting flange.

8. Apparatus as claimed in claim 7, in which the rod is a screw-threaded bolt which screw-engages the mounting flange and is axially movable by means of a complementary nut screw engaging same at the side of the mounting flange remote from the tube plate.

9. Apparatus as claimed in claim 7, in which the rod extends through the mounting flange and has pivotally secured to its end remote from the tube plate a cam adapted to react against the mounting flange, or an intermediate distance piece, to effect axial movement of the rod.

10. Apparatus as claimed in claim 9, in which the cam is provided with an operating handle.

11. Apparatus as claimed in any one of claims 6 to 10, in which the device for securing the welding torch in position comprises a second support bush aligned with but spaced from the first-mentioned support bush and located outboard of the latter from the tube plate, the second support bush being connected to the mounting flange by at least one pillar and adjustably receiving the welding torch to permit axial adjustment of the latter and consequently of its electrode relative to the tube end and tube plate to be welded together.

12. An assembly of a welding torch and the supporting apparatus as claimed in any one of claims 1 toll.

13. An assembly as claimed in claim 12 in which the welding torch is housed within the locating sleeve and adjustably co-operates with the second support bush for axial adjustment thereof.

14. An assembly as claimed in claim 13 in which the welding torch is adjustably screw-engaged with the second support bush.

15. An assembly as claimed in claim 14, in which a locknut is provided to secure the welding torch in adjusted position relative to the second support bush.

16. An assembly as claimed in any one of claims 12 to 15 in which the welding torch is a gas torch with at its gas outlet an electrode.

17. An assembly as claimed in claim 16 comprising a gas seal between the welding torch and the locating sleeve.

18. An assembly as claimed in claim 16 or 17 comprising a gas seal between the locating sleeve and the first-mentioned support bush.

19. A tube welding torch and support assembly, substantially as hereinbefore described with reference to the accompanying drawings.