JPH0224544Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus for TIG welding the inner surfaces of heat exchanger tubes, etc. of a heat exchanger.

Conventionally, an apparatus for welding the inner surface of a tube such as a heat transfer tube has been constructed as shown in FIG. 1, for example. That is, f in the figure is a heat exchanger tube to be welded, and a welding torch is inserted into this heat exchanger tube f. This welding torch is constructed as shown in FIG. That is, e is a current-carrying tube, and an insulator d made of ceramic or the like is attached to the tip of the current-carrying tube e. A ceramic nozzle b is screwed onto the tip of the current-carrying tube e, and is configured to be fixed in any position by tightening a lock nut c. A tungsten electrode is attached to the tip of the current-carrying tube e.

By the way, when assembling such a conventional welding torch, after aligning the ceramic nozzle b and the tungsten electrode a, the lock nut c is tightened and the ceramic nozzle b is assembled.
was fixed. Therefore, a gap g is formed between the lock nut c and the insulator d, and during welding, the high frequency for arc starting leaks from the energizing tube e to the heat transfer tube f through this gap g, resulting in dielectric breakdown of the welding torch. In some cases, the inner surface of the heat exchanger tube was damaged.

In addition, in the conventional welding method described above, the distance between the tungsten electrode a and the inner surface of the heat exchanger tube f, that is, the arc length, cannot be determined, so the welding torch and the heat exchanger tube f must be aligned with high precision. .

The present invention was developed based on the above-mentioned circumstances.The purpose of the present invention is to create an inner surface of the tube that does not cause current leakage and that allows easy positioning of the tungsten electrode and the inner surface of the tube to be welded. The purpose is to provide welding equipment.

That is, the present invention includes a torch body inserted into a pipe to be welded, an energizing tube inserted into the torch body, a tungsten electrode provided at the tip of the energizing tube, and a tungsten electrode provided on the outer periphery of the tip of the torch body. a nozzle that is screwed in and has a hole in its side surface that allows the tip of the tungsten electrode to face the inner surface of the tube; an insulating tube that is fitted around the outer periphery of the torch body; and a nozzle that is provided between the insulating tube and the nozzle. The insulating bushing is fitted with an insulating tube and a nozzle, and a guide body is provided at the tip of the nozzle and comes into contact with the inner surface of the tube to be welded to position the tungsten electrode. Therefore, during assembly, the position of the tungsten electrode and nozzle can be adjusted by moving the current-carrying tube relative to the torch body, and since the current-carrying tube is fixed at the base end of the torch body. ,
No gap is formed in the insulator at the tip of the torch body, and no dielectric breakdown occurs.
Further, since a guide body is provided at the tip of the nozzle, the tungsten electrode is accurately and easily positioned with respect to the inner surface of the pipe to be welded by this guide body.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 2 to 5. In the figure, reference numeral 1 denotes a torch body, into which a current-carrying tube 9 is inserted. A tungsten electrode 10 is provided at the tip of the current-carrying tube 9, and the tip is fixed with a fixing screw 11 so as to face the inner surface of the tube to be welded. Further, a cylindrical ceramic nozzle 5 is screwed into the outer periphery of the tip of the torch body 1. A hole 21 is formed in the side surface of the ceramic nozzle 5, and the tip of the tungsten electrode 10 is made to face the inner surface of the tube through the hole 21.

An insulating tube 2 is fitted around the outer periphery of the torch body 1, and an insulating bush 4 is provided between the insulating tube 2 and the ceramic nozzle 5. An insulating step 4a is formed at the base end of the insulating bush 4.
a is fitted onto the outer periphery of the end of the insulating tube 2, so that no gap is formed between the insulating bush 4 and the insulating tube 2. Also,
A stepped portion 5 also fits into the base end of the ceramic nozzle 5.
a is formed, and this fitting step portion 5a fits into the outer periphery of the end of the insulating bushing 4, and the ceramic nozzle 5
The structure is such that no gap is formed between the insulating bushing 4 and the insulating bushing 4. Note that 6 in the figure is an insulating screw that prevents the insulating bush 4 from rotating. Further, the outer periphery of the ceramic nozzle 5 is covered with a nozzle outer cylinder 7. Anti-rotation legs 7a are formed at the base end of the nozzle outer cylinder 7, and these anti-rotation legs 7a fit into anti-rotation grooves 4a formed on the outer periphery of the insulating bushing 4 and are stopped. It is fixed by a ring 8 to prevent the ceramic nozzle 5 from rotating.

Further, a power cable 18 is connected to the base end of the above-mentioned current-carrying tube 9. Note that 19 is an insulating tube that accommodates the proximal end of the current-carrying tube 9 and the power cable 18, and insulates them.

Further, a guide body 13 is attached to the tip of the ceramic nozzle 5 with a mounting bolt 12 and a lock nut 14. A pair of abutting portions 13a are integrally provided on the guide body 13 on the side from which the tungsten electrode 10 protrudes. Further, a ball plunger 15 is attached to this guide body 13. This ball plunger 15 is configured to project a ball 15a by the biasing force of a spring or the like, and bring this ball 15a into contact with the inner surface of the pipe to be welded.

Next, the operation of this embodiment will be explained. This welding torch is inserted into the pipe to be welded as shown in FIG. In this case, the ball 15a of the ball plunger 15 of the guide body 13 attached to the tip of the ceramic nozzle 5 is pressed against the inner surface of the tube, and the reaction force causes the contact portions 13a, 13 of the guide body 13 to
a comes into contact with the inner surface of the tube, thereby positioning the tungsten electrode 10. Therefore, welding work can be performed easily and accurately.
Furthermore, in this embodiment, an insulating bushing 4 is provided between the insulating tube 2 and the ceramic nozzle 5, so that the insulating bushing 4 and the insulating bushing 4 are fitted together. There is no gap between the ceramic nozzle 5 and the insulating bush 4, and leakage of high frequency current can be prevented.

As described above, the present invention includes a torch body inserted into a pipe to be welded, a current-carrying tube inserted into the torch body, a tungsten electrode provided at the tip of the current-carrying tube, and a tip of the torch body. a nozzle that is screwed into the outer periphery and has an opening on the side surface that allows the tip of the tungsten electrode to face the inner surface of the tube; an insulating tube fitted on the outer periphery of the torch body; and a nozzle provided between the insulating tube and the nozzle. The insulating bushing is fitted with the insulating tube and the nozzle, and the guide body is provided at the tip of the nozzle and comes into contact with the inner surface of the tube to be welded to position the tungsten electrode. Therefore, when the torch body is inserted into the pipe to be welded, the tungsten electrode is positioned by the guide provided at the tip of the nozzle, so the distance from the tip of the tungsten electrode to the inner surface of the tube must be kept constant. This makes it easy to center the torch body and tube. Furthermore, since an insulating bushing that fits into the insulating tube and nozzle is provided between the insulating tube and the nozzle, gaps are generated between the insulating tube and the insulating bushing and between the nozzle and the insulating bushing. There is no such thing,
Leakage of high frequency current can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional welding torch.
2 to 6 show an embodiment of the present invention,
Fig. 2 is a side view of the whole, Fig. 3 is a vertical sectional view of the tip of the torch, Fig. 4 is a view taken in the direction of - arrow in Fig. 3, and Fig. 5 is a longitudinal sectional view of the torch tip.
The figure is a view taken along the - arrow in FIG. 3, and FIG. 6 is a longitudinal sectional view of the proximal end of the torch. 1...Torch body, 4...Insulating bushing, 5...
...Ceramic nozzle, 9...Electricity tube, 10
... Tungsten electrode, 13 ... Guide body, 13
a... Contact part, 18... Power cable.

Claims (1)

[Scope of utility model registration request] A torch body inserted into the pipe to be welded, an energizing tube inserted into the torch body, a tungsten electrode provided at the tip of the energizing tube, and a tungsten electrode screwed into the outer periphery of the tip of the torch body and attached to the side surface. a nozzle having a hole in which a tip of a tungsten electrode faces the inner surface of the tube; an insulating tube fitted on the outer periphery of the torch body; and a nozzle provided between the insulating tube and the nozzle, An apparatus for welding an inner surface of a tube, comprising an insulating bushing that fits into each other, and a guide body provided at the tip of the nozzle and abutting against the inner surface of the tube to be welded to position the tungsten electrode.