WO2004026520A2

WO2004026520A2 - Torch head for welding torches and gas nozzle, contact nozzle, and insulation nozzle for such a torch head

Info

Publication number: WO2004026520A2
Application number: PCT/AT2003/000276
Authority: WO
Inventors: Walter Wimroither
Original assignee: Fronius International Gmbh
Priority date: 2002-09-18
Filing date: 2003-09-17
Publication date: 2004-04-01
Also published as: AU2003260163A1; DE20380291U1; ATA14012002A; AT411972B; WO2004026520A3

Abstract

The invention relates to a torch head (1) for welding torches, comprising a base member (2) that is provided with a non-consumable electrode (7) which is surrounded by a contact nozzle (6). An insulating sleeve (8) and a combustion gas inlet (9) are disposed between the electrode (7) and the contact nozzle (6). The inventive torch head further comprises an internally threaded (4) gas nozzle (3) which surrounds the contact nozzle (6) and is screwed onto a corresponding external thread (5) that is located on the base member (2), and a slanted, annular stop area (11) which enters in contact with a corresponding area (12) of the gas nozzle in the screwed-on state. An inert gas duct (10) is disposed between the gas nozzle (3) and the contact nozzle (6). In order to create a torch head (1) in which the expendable parts can be replaced in a particularly simple manner and are placed in a particularly optimal position, the slanted, annular stop area (11) borders the external thread (5) on the base member (2). The inside of the contact nozzle (21) is provided with areas (21), e.g. ribs, for centering the insulating sleeve (8).

Description

Torch head for welding torches as well as gas nozzle, contact nozzle and insulating nozzle for such a torch head

The invention relates to a torch head for welding torches, in particular for plasma welding torches with a base body, with a non-melting electrode, which electrode is surrounded by a contact nozzle, an insulating sleeve and a fuel gas supply being arranged between the electrode and the contact nozzle, furthermore with a contact nozzle surrounding gas nozzle, which gas nozzle has an internal thread for screwing onto a corresponding external thread on the base body, and with an oblique, annular stop surface for contact with a corresponding surface of the gas nozzle in the screwed-on state, and a protective gas supply is arranged between the gas nozzle and the contact nozzle.

The invention further relates to a gas nozzle with an internal thread for screwing onto a corresponding external thread arranged on the burner head, an oblique, annular surface being arranged at the rear end opposite the outlet opening for the protective gas, which surface is screwed onto a corresponding stop surface on the burner head Burner head comes to rest.

Furthermore, the invention relates to a contact nozzle for an above-mentioned burner head with a receptacle for an electrode surrounded by an insulating sleeve and an insulating sleeve for such a burner head.

Welding torch, in particular for plasma welding processes, but also arc welding processes under a protective gas atmosphere, such as IG (metal inert gas) -, MAG (metal active gas) -, TIG (tungsten inert gas) -, TIG (tungsten inert) Gas) welding process, have a torch head as the core. In addition to the components mentioned, such a burner head has connections for the electrical lines for supplying electrical energy to the electrode and for the contact sleeve and supply lines for the fuel gas and protective gas. When plasma welding is between the inside of the contact nozzle Centered non-melting electrode and the contact nozzle supplied electrical energy, whereupon an arc builds up between the non-insulated tip of the electrode and the contact nozzle. The fuel gas supplied between the contact nozzle and the electrode ionizes and emerges from the contact nozzle in the direction of the workpiece as a plasma jet due to the gas flow. A protective gas is supplied via the gas nozzle, which is arranged concentrically around the contact nozzle, which surrounds the plasma jet and protects the melt on the workpiece from the surrounding air. In such torch heads for plasma or arc welding torches, in particular the gas nozzle, the contact sleeve, the insulating sleeve and the electrode are wear parts which have to be replaced after a corresponding operating time. In addition, torch heads can also be adapted to certain conditions by changing the components mentioned, or can be converted for other welding processes.

A torch head of an arc welding or cutting torch, but preferably with a melting wire electrode, is described for example in WO00 / 73700 AI. The replacement of wear parts, e.g. the contact nozzle, relatively complex.

In addition to the great effort involved in replacing the wearing parts, there is often no exact positioning of the electrode, but also of the contact nozzle and gas nozzle, as a result of which the welding torch does not function optimally and the quality of the weld seam suffers as a result. Another disadvantage of wearing parts of known welding torches is their complicated manufacture and the associated high costs.

No. 4,628,177 A describes a welding torch of the type in which the gas nozzle has an oblique stop surface and the base body of the torch head has a corresponding oblique stop surface. The chamfer is used to seal the inside of the welding torch from the environment so that no shielding gas can escape. The oblique stop surface is spaced from the external thread on the burner body, so that the gas nozzle does not have a good centering effect on the burner body. occurs.

US 4,743,734 A shows a nozzle for a plasma arc welding torch, which is made up of three parts that can be screwed together. Here, too, oblique, ring-shaped stop surfaces are formed on the parts of the nozzle against which corresponding surfaces of the adjacent parts bear.

Finally, US Pat. No. 3,783,233 A shows a gas nozzle for a welding torch, which is attached to the torch body via an insulating threaded bushing. Sliding on the gas nozzle has disadvantages compared to screwing it on with regard to the exact centered positioning.

The object of the present invention is therefore to provide an abovementioned burner head, the wearing parts of which, such as the gas nozzle, contact nozzle, insulating sleeve and electrode, can be replaced as quickly and easily as possible, and which permits exact positioning of the wearing parts on the base body. In addition, the components of the burner head should be constructed as simply as possible and thus be inexpensive to manufacture.

Another object of the present invention is to provide a gas nozzle, contact nozzle and insulating sleeve for a torch head for welding torches, in particular for plasma welding torches, which can be arranged as quickly and easily as possible on the base body of the torch head, should be able to be positioned as precisely as possible on it and above easy and cheap to manufacture.

The first object according to the invention is achieved in that the oblique, annular stop surface is adjacent to the external thread on the base body. The oblique stop surface causes an exact, centered positioning of the gas nozzle in relation to the base body of the burner head, as would not be the case with a simple assembly using a thread, since each thread has a certain amount of play. An eccentric arrangement of the gas nozzle in relation to the contact nozzle and electrode would asymmetrical flow conditions for the gas and for the arc created, which would reduce the quality of the weld. The centering device of the burner head formed by the inclined stop surface is very easy and inexpensive to manufacture and also results in very simple assembly of the gas nozzle on the burner head. The sloping surface also increases the surface area and thus creates a better seal even without additional sealing elements.

The oblique annular stop surface can be integrated in the base body or can also be formed by an annular body which can be screwed or plugged onto the base body of the burner head. In this case, the annular body can be formed from a different material than the basic body.

For example, the ring-shaped body can consist of ceramic.

To seal the burner head to avoid the undesired escape of protective gas, a sealing ring can be arranged on the stop surface, which can be made of elastic plastic, for example. The elastic plastic must withstand the temperatures that occur at the corresponding point on the torch head during welding.

An internal thread for screwing on the contact nozzle provided with a corresponding external thread is advantageously arranged on the base body, so that the contact nozzle can be quickly and easily removed and reinstalled.

If the shielding gas supply leads into essentially radially arranged openings on the base body of the burner head, it can be achieved that the annular space formed between the gas nozzle and the contact nozzle also in the rear, i.e. the area opposite the nozzle opening, is filled with protective gas and, as a result, optimal flow conditions prevail at the outlet of the protective gas at the opening of the gas nozzle. In addition, a plurality of openings or rows of openings can also be arranged next to one another in the axial direction.

The radial openings are advantageously around the

- 5 - arranged the entire circumference of the base body at equal angular intervals.

Ceramic has proven to be the ideal material for the gas nozzle. However, special plastics are also conceivable for certain applications.

The contact nozzle, which must be made of an electrically conductive material, is advantageously made of copper or a copper alloy.

The insulating sleeve in the burner head, which is arranged between the electrode and the contact nozzle, is preferably made of ceramic, so that it withstands the temperatures that occur and provides the appropriate electrical insulation.

The object of the invention is also achieved by a gas nozzle for an above-mentioned burner head with an internal thread for screwing onto a corresponding external thread arranged on the burner head, in which the stop surface on the burner head adjoins the end of the external thread on the burner head, so that the gas nozzle is centered.

According to a further feature of the invention, the inclined surface has an inclination of essentially 30 ° with respect to the surface of the internal thread. This is advantageous on the one hand with regard to the production of the gas nozzle and the stop surface on the burner head and on the other hand for the centering effect.

In order to achieve optimal flow conditions for the protective gas, the outlet opening is tapered in the direction of the flow of the protective gas.

The further object of the invention is achieved by a contact nozzle for an abovementioned burner head with a receptacle for an electrode surrounded by an insulating sleeve, the receptacle having a plurality of regions arranged essentially in the longitudinal direction of the receptacle, the inner diameter of the receptacle being smaller at the locations of these regions is as that outside of these areas, so channels between the areas be formed. This construction ensures that the insulating sleeve and subsequently the electrode in the contact nozzle are centered. In contrast to the prior art, according to which the receptacle of the contact nozzle is essentially cylindrical and the insulating sleeve has webs in the longitudinal direction, the receptacle is modified accordingly in the contact nozzle described in order to achieve optimal centering of the insulating sleeve. The corresponding areas with a smaller inner diameter can be produced relatively easily since the preferred material for the contact nozzle is copper or a copper alloy. The fuel gas can flow through the channels formed between the regions into the space between the contact nozzle and the electrode, which is ionized to form a plasma jet.

According to one embodiment of the contact nozzle, the receptacle can have a cross section in the form of an equilateral polygon. This can be a cross section in the form of an equilateral triangle, quadrangle, pentagon, hexagon or the like. The corners of the polygon form the center of the channels through which the fuel gas flows, while the edges of the polygon in the middle area serve as a support for the insulating sleeve.

According to another exemplary embodiment, the regions can also be formed by ribs or the like.

In order to achieve certain flow conditions for the fuel gas in the space between the contact nozzle and the electrode, the ribs and thus the channels arranged between the ribs can be arranged in a spiral.

The receptacle in the contact nozzle can have a section with a smaller inner diameter than the rest of the receptacle at the end assigned to the tip of the electrode. As a result, a stop is formed for the insulating sleeve placed in the contact nozzle and a cross-sectional constriction is formed for the fuel gas.

A conical area can be arranged between the section with a smaller inner diameter and the rest of the receptacle optimal flow conditions for the fuel gas.

If the contact nozzle has a conical area on its outside, an optimal positioning of the contact nozzle on the burner head can be achieved.

The last object of the invention is achieved by an insulating sleeve for an above-mentioned burner head with an above-mentioned contact nozzle, in which the outside is essentially cylindrical, and with indentations or the like on the end of the insulating sleeve facing the tip of the electrode. are arranged to guide the fuel gas between the electrode and contact nozzle. In contrast to insulating sleeves according to the prior art, which have ribs or the like on the outside for a centered placement within the contact nozzle, such cylindrical insulating sleeves are particularly simple and inexpensive to manufacture. The fuel gas can flow through the indentations through the channels between the contact nozzle and the insulating sleeve and then over the indentations in the direction of the opening of the contact nozzle.

The indentations can simply be formed by a plurality of grooves which are preferably arranged at equal angular intervals.

The present invention is explained in more detail with reference to the accompanying drawings, which show exemplary embodiments of the burner head, the gas nozzle, the contact nozzle and the insulating sleeve.

In it show:

1 shows a cross section through an embodiment of a torch head for a plasma welding torch.

2 shows a section through an exemplary embodiment of a gas nozzle;

3 shows a section through an embodiment of a contact nozzle; 4a and 4b show a side view of two different embodiments of contact nozzles according to FIG. 3;

5 shows a contact nozzle with an insulating sleeve arranged therein;

6 shows a contact nozzle with an insulating sleeve and electrode arranged therein;

FIG. 7 shows a section along the section line VII-VII according to FIG. 6;

8 shows a section through an exemplary embodiment of an insulating sleeve;

FIG. 9 shows a side view of the insulating sleeve according to FIG. 8;

10 shows a section through another embodiment of an insulating sleeve; and

11 is a side view of the insulating sleeve according to FIG. 10.

1 shows a torch head 1 for a plasma welding torch consisting of a base body 2, at the end of which a gas nozzle 3 with an internal thread 4 is screwed onto a corresponding external thread 5 on the base body 2. Furthermore, a contact nozzle 6 made of electrically conductive material is arranged on the burner head, in which a non-melting electrode 7 is placed. Between the contact nozzle 6 and the electrode 7, an insulating sleeve 8, which is made of ceramic, for example, is arranged. In addition, feeds 9 for the burner gas, which flows in between the contact nozzle 6 and the electrode 7, are found on the burner head 1. By supplying electrical energy between the contact nozzle 6 and the electrode 7, an arc is ignited between the tip of the electrode 7 and the contact nozzle 6, which in turn ionizes the inflowing fuel gas and leads to the formation of a plasma jet at the tip of the burner head 1. Protective gas flows into the space between the gas nozzle 3 and the contact nozzle 6 via a feed 10, which protective gas surrounds the plasma jet and thus the welding point on the workpiece (not shown) from the surrounding air protects.

For optimal function, the electrode 7, the insulating sleeve 8, the contact nozzle 6 and the gas nozzle 3 must be arranged in the center. According to the invention, centering takes place via an oblique ring-shaped stop surface 11 on the burner head 1, which comes into contact with the corresponding surface 12 when the gas nozzle 3 is screwed on. The oblique annular stop surface 11 can be integrated on the base body 2 of the burner head 1 or can be designed as an annular body 13 which e.g. is screwed or plugged onto the base body 2. The annular body 13, like the gas nozzle 3, can be made of ceramic. Due to the oblique stop surface 11, the surface at the transition between the base body 2 and the gas nozzle 3 is also enlarged, and thus a better seal is created even without additional sealing elements. In addition, however, a sealing ring 14, for example made of elastic plastic, can also be arranged on the oblique stop surface 11 in order to achieve an even better seal of the space formed between the gas nozzle 3 and the contact nozzle 6 from the environment and thus to an undesired escape of protective gas to the rear prevent.

In order to make it easy to change the contact nozzle 6 on the burner head 1, an internal thread 15 for screwing on the contact nozzle 6 provided with a corresponding external thread 16 is arranged on the base body 2 of the burner head 1 or on a body connected to it. For optimum flow conditions in the intermediate space between gas nozzle 3 and contact nozzle 6, the protective gas feed 10 advantageously opens into essentially radially arranged openings 17 on the base body 2. This prevents anyone from forming areas in the space between the gas nozzle 3 and the contact nozzle 6 that do not are filled with protective gas. The openings 17 are advantageously arranged around the entire circumference of the base body 2 of the burner head 1 at equal angular distances from one another. In addition, a plurality of openings 17 or rows of openings 17 can be arranged side by side in the axial direction. FIG. 2 shows a sectional view of the gas nozzle 3 according to FIG. 1 in an enlarged representation. The internal thread 4 for screwing the gas nozzle 3 onto a corresponding external thread 5 arranged on the burner head 1 can be seen. Arranged at the rear end 19 opposite the outlet opening 18 of the gas nozzle 3 is the oblique annular surface 12, which comes into contact with the burner head 1 when it is screwed onto the burner head 1 against a corresponding stop surface 11 at the end of the external thread 5. This results in an optimal centering of the gas nozzle 3 on the burner head 1. The inclination of the inclined surface 12 is advantageously essentially 30 ° with respect to the surface of the internal thread 4 of the gas nozzle 3. To achieve optimal flow conditions of the protective gas, the outlet opening (18) is in the direction of the Shielding gas flow tapered.

Fig. 3 shows a section through a contact nozzle 6 for a torch head 1 of a plasma welding device. The contact nozzle 6 has a receptacle 20 for an electrode 7 surrounded by an insulating sleeve 8. To screw the contact nozzle 6 onto the base body 2 or a body of the burner head 1 connected thereto, an external thread 16 is arranged on the outside. The receptacle 20 of the contact nozzle 6 has, according to the invention, a plurality of regions 21 arranged essentially in the longitudinal direction of the receptacle 20, the inside diameter Di of the receptacle 20 at the locations of these regions 21 being smaller than that inner diameter D _A outside of these regions 21.

As can be seen better from the exemplary embodiments according to FIGS. 4a and 4b, these regions 21 can be formed, for example, by corresponding ribs or the edges of a polygon. Channels 22 are formed between the regions 21 with a smaller inner diameter Di, through which the fuel gas can reach the tip of the electrode 7. The arrangement of the regions 21 enables the insulating sleeve 8 to be optimally centered within the contact nozzle 6.

5, which shows a section through a contact nozzle 6 with an insulating sleeve 8 arranged therein. The insulating sleeve 8 abuts in the receptacle 20 of the contact nozzle 6 a portion 23 which is conical. In order to achieve optimal flow conditions at the outlet of the contact nozzle 6, the receptacle 20 is provided at the end associated with the tip of the electrode 7 with a section 24 with a smaller inner diameter than the rest of the receptacle 20. For the optimal arrangement of the contact nozzle 6 on the burner head 1, this can have a conical region 24 on the outside. This conical area 25 then, as can be seen in FIG. 1, bears against a corresponding component of the burner head 1.

FIGS. 6 and 7 show an arrangement of an electrode 7 together with an insulating sleeve 8 in a contact nozzle 6. 7, the channels 22 formed between the regions 21 between the contact nozzle 6 and the insulating sleeve 8, through which the fuel gas flows in the direction of the tip of the electrode 7, can be clearly seen.

Finally, FIGS. 8 and 9 and FIGS. 10 and 11 show sectional representations and side views of two different embodiments of insulating sleeves 8. The insulating sleeve 8 is essentially cylindrical and has indentations 27 on the end face facing the tip of the electrode 7. In the embodiment according to FIGS. 8 and 9, these indentations 27 are formed by four grooves which are each arranged at equal angular intervals of 90 °. Through these indentations 27, the fuel gas first passes through the channels 22 between the contact nozzle 6 and the insulating sleeve 8 and then via the indentations 27 to the tip of the electrode 7, where it is ionized in the arc between the electrode 7 and the contact nozzle 6. In the embodiment according to FIGS. 10 and 11, the indentations 27 are round. The number and the shape of the indentations 27 can be made almost arbitrarily.

Claims

Claims:

1. torch head (1) for welding torches, in particular for plasma welding torches with a base body (2), with a non-melting electrode (7), which electrode (7) is surrounded by a contact nozzle (6), between the electrode (7) and the Contact nozzle (6) an insulating sleeve (8) and a fuel gas supply (9) is arranged, further with a gas nozzle (3) surrounding the contact nozzle (6), which gas nozzle (3) has an internal thread (4) for screwing onto a corresponding external thread (5 ) at the

Has base body (2), and with an oblique, annular stop surface (11) for bearing against a corresponding surface (12) of the gas nozzle in the screwed-on state, and a protective gas supply (10) between the gas nozzle (3) and the contact nozzle (6) is arranged, characterized in that the oblique, annular stop surface (11) adjoins the external thread (5) on the base body (2).

2. Burner head according to claim 1, characterized in that the stop surface (11) is formed by an annular body (13) which can be screwed or plugged onto the base body (2) of the burner head (1).

3. Burner head according to claim 2, characterized in that the annular body (13) is made of ceramic.

4. Burner head according to one of claims 1 to 3, characterized in that a sealing ring (14) is arranged on the stop surface (11).

5. Burner head according to claim 4, characterized in that the sealing ring (14) consists of elastic plastic.

6. Burner head according to one of claims 1 to 5, characterized in that an internal thread (15) for screwing on the contact nozzle (6) provided with a corresponding external thread (16) is arranged on the base body (2).

7. Burner head according to one of claims 1 to 6, characterized in that the protective gas supply (10) essentially radially arranged openings (17) on the base body (2) open.

8. Burner head according to claim 7, characterized in that the openings (17) around the entire circumference of the base body (2) are arranged at equal angular intervals from one another.

9. burner head according to one of claims 1 to 8, characterized in that the gas nozzle (3) is made of ceramic.

10. Burner head according to one of claims 1 to 9, characterized in that the contact nozzle (6) is made of copper or a copper alloy.

11. Burner head according to one of claims 1 to 10, characterized in that the insulating sleeve (8) is made of ceramic.

12. Gas nozzle (3) for a burner head according to one of claims 1 to 11 with an internal thread (4) for screwing onto a corresponding, on the burner head (1) arranged external thread (5), wherein at the rear, the outlet opening (18) for the An oblique, annular surface (12) is arranged opposite the protective gas, which comes to rest on a corresponding stop surface (11) on the burner head (1) when screwed onto the burner head (1), characterized in that the stop surface (11 ) on the burner head (1) adjoins the end of the external thread (5) on the burner head (1), so that the gas nozzle (3) is centered.

13. Gas nozzle (3) according to claim 12, characterized in that the inclined surface (12) has an inclination of substantially 30 ° with respect to the surface of the internal thread (4).

14. Gas nozzle according to claim 12 or 13, characterized in that the outlet opening (18) is tapered in the direction of the flow of the protective gas.

15. Contact nozzle (6) for a burner head (1) according to one of claims 1 to 11 with a receptacle (20) for an electrode (7) surrounded by an insulating sleeve (8), characterized in that that the receptacle (20) has a plurality of regions (21) arranged essentially in the longitudinal direction of the receptacle (20), the inner diameter (Di) of the receptacle (20) at the locations of these regions (21) being smaller than that inner diameter (D _A ) outside of these areas (21), so that channels (22) are formed between the areas (21).

16. Contact nozzle according to claim 15, characterized in that the receptacle (20) has a cross section in the form of an equilateral polygon.

17. Contact nozzle according to claim 15, characterized in that the areas (21) by ribs or the like. are formed.

18. Contact nozzle according to claim 17, characterized in that the ribs or the like are arranged spirally.

19. Contact nozzle according to one of claims 15 to 18, characterized in that the receptacle (20) at the end of the electrode (7) associated end has a portion (24) with a smaller inner diameter than the rest of the receptacle (20).

20. Contact nozzle according to claim 19, characterized in that a conical region (23) is arranged between the section (24) with a smaller inner diameter and the rest of the receptacle (20).

21. Contact nozzle according to one of claims 15 to 20, characterized in that the contact nozzle (6) has a conical region (25) on the outside.

22. Insulating sleeve (8) for a burner head (1) according to one of claims 1 to 11 with a contact nozzle (6) according to one of claims 15 to 21, characterized in that the outside is essentially cylindrical, and that on the, the tip of the electrode (7) facing the end face (26) of the insulating sleeve (8) indentations (27) or the like for guiding the fuel gas between the electrode (7) and contact nozzle (6) are arranged.

23. Insulating sleeve according to claim 22, characterized in that the indentations (27) are formed by a plurality of grooves, preferably arranged at equal angular intervals.