Gas Nozzle for the Outflow of a Protective Gas Stream, and Torch with a Gas Nozzle

Abstract

A gas nozzle for the outflow of a protective/shielding gas stream from a gas outlet of the gas nozzle having a gas distributor/diffuser section has a double-walled configuration at least in a partial area of the gas distributor/diffuser section in order to create a flow space for the protective/shielding gas stream. The invention also relates to a torch neck and to a method for thermally joining at least one workpiece, in particular for arc joining, preferably for arc welding or arc brazing/soldering, with an electrode which is arranged in the torch neck or with a wire for producing an arc between the electrode or the wire and the workpiece, and having a gas nozzle for the outflow of a protective/shielding gas stream from a gas outlet.

Claims

1. A gas nozzle (1) for the outflow of a shielding gas stream out of a gas outlet (2), comprising: a gas diffuser section (3) with a double wall at least in a partial area thereof in order to create a flow space (16) for the shielding gas stream.

2. The gas nozzle (1) according to claim 1, wherein the gas diffuser section (3) and the gas nozzle (1) are formed monolithically.

3. The gas nozzle (1) according to claim 1, wherein the gas diffuser section (3) is formed by a gas diffuser (4) that is attached to the gas nozzle (1).

4. The gas nozzle (1) according to claim 1, wherein the gas diffuser section (3) has two or more gas outlet openings (8) along its circumference so that the gas outlet (2) is fluidly connected to the gas outlet openings (8).

5. The gas nozzle (1) according to claim 1, wherein the gas nozzle (5) has an inner diameter that is defined by the gas nozzle (1) and the adjacent gas diffuser section surface (6), and wherein said inner diameter is configured so as to be uniform downstream from the gas stream or else conically decreasing.

6. The gas nozzle (1) according to claim 1, wherein the gas diffuser (4) is made of a metal or is made of impact-resistant glass ceramics.

7. The gas nozzle (1) according to claim 1, wherein the gas diffuser section (3) or the gas diffuser (4) is substantially flush with the gas nozzle (2), at least in certain sections.

8. The gas nozzle (1) according to claim 3, wherein the gas diffuser (4) is joined to the gas nozzle (1) with a positive connection and/or a non-positive connection and/or a bonded connection.

9. The gas nozzle (1) according to claim 3, wherein the gas diffuser (4) is detachably connected to the gas nozzle (1).

10. The gas nozzle (1) according to claim 3, wherein the gas diffuser (4) is non-detachably connected to the gas nozzle (1).

11. A torch neck (10) for arc joining at least one workpiece, comprising: an electrode arranged in the torch neck (10) or a wire for generating an arc between the electrode or the wire and the workpiece, and a gas nozzle (1) for the outflow of a shielding gas stream out of a gas outlet (2), said gas nozzle (1) comprising a gas diffuser section (3) with a double wall at least in a partial area thereof in order to create a flow space (16) for the shielding gas stream.

12. The torch neck (10) according to claim 11, further comprising a filter ring (12) made of sintered material and configured to reduce pressure installed in the gas nozzle (1) downstream in a partial area of the gas diffuser section (3) that is configured with the double wall.

13. The torch neck (10) according to claim 11, further comprising an inner pipe (13) of the torch neck (10) that is electrically connected to a contact tip (11) and that is electrically insulated by an electric insulator (15) vis-à-vis an outer pipe (14) of the torch neck that is at a distance from the inner pipe (13).

14. The torch neck (10) according to claim 11, further comprising a spatter protection means (9) comprising of fiberglass-filled PTFE installed before an insulation cap (15).

15. A torch having a torch neck (10) according to claim 11.

16. A method for arc joining at least one workpiece, comprising: providing an electrode or a wire for generating an arc between the electrode or the wire and the workpiece, directing a shielding gas stream out of a gas nozzle (1), said gas nozzle (1) comprising a gas diffuser section (3) with a double wall at least in a partial area thereof in order to create a flow space (16) for the shielding gas stream, and modifying a direction of flow of the shielding gas at least once with the gas diffuser section (3) so that the duration of flow is prolonged or the flow path of the shielding gas stream inside the gas nozzle (1) is lengthened, wherein the shielding gas stream surrounds the electrode or wire essentially annularly at the gas outlet (2) of the gas nozzle (1).

Description

DESCRIPTION OF THE DRAWINGS

[0077] In this context, the following is shown, at times schematically:

[0078] FIG. 1 part of a torch neck of a welding torch having a gas nozzle,

[0079] FIG. 2 a detailed view of the gas nozzle with a gas diffuser section,

[0080] FIG. 3 a detailed view of the gas nozzle, wherein the gas diffuser section and the gas nozzle are configured monolithically,

[0081] FIG. 4 a sectional view of the torch neck as shown in FIG. 1, and

[0082] FIG. 5 a part of a torch neck as shown in FIGS. 1 and 7, with a milling tool.

DETAILED DESCRIPTION

[0083] For the sake of clarity, identical components or those having the same effect are provided with the same reference numerals in the figures of the drawing shown below, making reference to an embodiment.

[0084] FIG. 1 shows a torch neck 10 with a nozzle tip holder 7 of a welding torch for thermally joining at least one workpiece, especially for arc joining, preferably arc welding or arc soldering. “MIG”, “MAG” and “TIG” are standard welding methods that are employed in sheet metal processing.

[0085] FIG. 5 differs from FIG. 1 in that a milling tool 18 is additionally depicted.

[0086] When it comes to shielding gas-assisted arc welding methods employing a consumable electrode (MSG), “MIG” stands for “metal inert gas” and “MAG” stands for “metal active gas”. MAG welding is a metal shielding-gas process (MSG) with active gas in which the arc burns between a continuously fed, consumable wire electrode and the material. The consuming electric supplies the filler material to form the weld seam.

[0087] In the case of shielding gas-assisted arc welding methods employing a non-consumable electrode (TSG), “TIG” stands for “tungsten inert gas”. The welding devices according to the invention can be configured as machine-controlled welding torches.

[0088] Arc welding devices generate an arc between the workpiece and a consumable or non-consumable welding electrode in order to fuse the material that is to be welded. A shielding gas stream shields the material that is to be welded as well as the welding site against the atmospheric gases, mainly N.sub.2, O.sub.2, H.sub.2, that are present in the ambient air.

[0089] In this context, the welding electrode is provided on a torch body of a welding torch that is connected to an arc welding device. The torch body normally has a group of internal components that carry the welding current and that conduct the welding current from a source of welding current in the arc welding device to the tip of the torch head and to the welding electrode, where it then generates the arc to the workpiece.

[0090] The shielding gas stream flows around the welding electrode, the arc, the welding bath and the heat-affected zone on the workpiece, and in this process, it is fed to these areas via the body of the welding torch. A gas nozzle 1 conveys the shielding gas stream to the front end of the torch head, where the shielding gas stream exits from the torch head around the welding electrode in an approximately annular pattern.

[0091] In the present embodiment, the torch neck 10 shown in FIGS. 1 and 5 and belonging to the torch head of the welding torch comprises the gas nozzle 1 for the outflow of a shielding gas stream out of a gas outlet 2 located at the front end of the gas nozzle 1. Such gas nozzles 1 are presented in detail in FIGS. 2 and 3.

[0092] FIGS. 1 to 3 and 5 also show that the gas nozzle 1, at least in a partial area of the gas diffuser section 3, is configured with a double wall in order to create a flow space 16 for the shielding gas stream. Thus, the configuration of the torch neck 10 with an appropriate geometry of the gas nozzle 1 having the gas diffuser section 3 and the gas outlet openings 8 ensures a sufficient retention time for the rectification and laminarization of the shielding gas stream, even at a small distance from the source of heat.

[0093] The embodiments of the gas nozzle 1 as shown in FIG. 2 and FIG. 3 differ in that the gas diffuser section 3 and the gas nozzle 1 as shown in FIG. 3 are formed monolithically. For instance, the gas nozzle with the gas diffuser section can be made particularly easily and efficiently employing 3D printing.

[0094] In contrast, FIG. 2 shows that the gas diffuser section 3 is formed by a gas diffuser 4 installed on the gas nozzle 1. In this manner, the gas nozzle 1 and the gas diffuser 4 constitute a module.

[0095] In both embodiments of the gas nozzle 1 according to FIG. 2 and FIG. 3, the gas diffuser section 3 has several gas outlet openings 8 arranged along its circumference approximately at an equal distance from each other, so that the gas outlet 2 is fluidly connected to the gas outlet openings 8.

[0096] It is through these gas outlet openings 8 that the shielding gas flows in a uniformly diffused manner over the circumference as a function of the radial distribution of the openings 8. The shielding gas stream exiting via the gas outlet openings 8 is thus deflected and diverted in the gas nozzle 1, resulting in an improved flow of the shielding gas in the direction of the gas outlet 2 in terms of the laminarity.

[0097] The module consisting of the gas nozzle 1 and the gas diffuser 4 or gas diffuser section 3 creates an extension of the flow channel for the shielding gas where the desired laminar flow can already be formed at the front end of the torch neck.

[0098] As can also be seen in FIGS. 1 to 5, the inner diameter 5 of the gas nozzle 1 defined by the gas nozzle 1 and by the adjacent gas diffuser section surface 6 is configured so as to be uniform downstream from the shielding gas stream or else conically decreasing, as seen in the direction of flow, that is to say, tapered. The welding process involving welding torches, particularly machine torches, can give rise to impurities on the gas nozzle 1 and on the gas outlet openings 8. These contaminated components are cleaned in an automated process by means of a milling tool 18, and are freed of weld spatter in this manner. Consequently, the wearing parts, especially the gas nozzle 1, the contact tip 11 or the spatter protection means 19 all have to withstand the mechanical stress during milling. Such a milling tool 18 is depicted in FIG. 5.

[0099] Owing to the configuration of the inner diameter 5 of the gas nozzle 1, the machine-guided milling tool 18 can be inserted into the gas nozzle 1 without any problem and moved all the way to the gas outlet openings 8 that are to be cleaned. For this reason, the gas diffuser 4 or gas diffuser section 3 arranged on the gas nozzle 1 can withstand being cleaned by means of a milling tool 18.

[0100] In the case of a multi-part configuration of the gas nozzle 1 having a gas diffuser 4 as shown in FIG. 2, the gas diffuser 4 is essentially flush with the gas nozzle 1, at least in certain sections. This allows optimal cleaning of the gas nozzle 1. The inner components, especially the contact tip 11 and its holder, do not need to be modified for this purpose. Consequently, automated cleaning using the milling tool 18 is easily possible.

[0101] In the case of the configuration of the gas nozzle 1 as shown in FIG. 2, the gas diffuser 4 is joined to the gas nozzle 1 with a positive and/or a non-positive and/or a bonded connection 1. In particular, it is conceivable for the gas diffuser 4 to be detachably connected to the gas nozzle 1, especially by being screwed or pressed into it. As an alternative, it is conceivable for the gas diffuser 4 to be firmly connected to the gas nozzle 1, especially by being glued on, soldered to or pressed into the gas nozzle 1.

[0102] As can be seen in the sectional view of the torch neck 10 as shown in FIG. 4 as well as in FIG. 1 and FIG. 5, an inner pipe 13 of the torch neck 10 that is electrically connected to a contact tip 11 is electrically insulated by the insulation cap 15 vis-à-vis the outer pipe 14 of the torch neck 10 that is at a distance from the inner pipe 13, preferably with a cover at the end of both pipes 13 and 14. The external parts of the torch or torch neck 10 are electrically insulated from the inner pipe 13 in order to prevent the welding currents from flowing over the torch housing.

[0103] Here, the gas nozzle carrier 17 not only has a function as a carrier for the gas nozzle 1 but also the function of diffusing the shielding gas. For this reason, the spatter protection means 9 and the insulation cap 15 can be configured so that their function is separate from the function of feeding the shielding gas. Therefore, the spatter protection means 9 can be configured so as to have a solid wall and consequently be sturdier than is the case with conventional designs in which shielding gas is fed through the spatter protection means via a hole. The insulation cap 15, in contrast, only has the task of positioning the pipes and the insulation, but does not have to seal off any media that is flowing through.

[0104] The shielding gas stream is conveyed in a double wall of the inner pipe 13. Due to the separation of the electric insulation 15 and the flow feed of the shielding gas, the electric insulation can be configured, for example, in the form of a cover and a spacer, at the end of the front ends of the inner pipe 13 and outer pipe 14.

[0105] As can also be seen in FIG. 1, FIG. 4 and FIG. 5, a spatter protection means 9 is provided as protection against weld spatter during the welding procedure. The shielding gas stream flows via the gas diffuser 4 or the gas diffuser section 3 axially to the spatter protection means 9 and is radially fed by the latter once again into the gas nozzle 1. The spatter protection means 9 preferably consists of fiberglass-filled PTFE and, during the cleaning of the contact tip 11 and of the gas nozzle 1 using the milling tool 18, it is at a sufficient distance from the latter so that the spatter protection means 9 is not damaged by the milling tool 18.

[0106] Here, the spatter protection means 9 fulfills a double function in that it is not only provided as protection against weld spatter but also assumes the function of the electric insulator 15. In this manner, a single component, namely, the spatter protection means 9 or the electric insulator 15, has a dual function.

[0107] Owing to the shortening of the gas nozzle 1, it can happen that the retention time of the shielding gas stream in the gas nozzle 1 is no longer sufficient to ensure laminarization of the shielding gas. For this reason, a filter ring 12 made of sintered material is provided for pressure-reduction purposes. The filter ring 12 is installed in the gas nozzle 1 downstream in a partial area of the gas diffuser section 3 that is configured with a double wall.

LIST OF REFERENCE NUMERALS

[0108] 1 gas nozzle [0109] 2 gas outlet [0110] 3 gas diffuser section [0111] 4 gas diffuser [0112] 5 inner diameter [0113] 6 gas diffuser sectional surface [0114] 7 nozzle tip holder [0115] 8 gas outlet opening [0116] 9 spatter protection means [0117] 10 torch neck [0118] 11 contact tip [0119] 12 filter ring [0120] 13 inner pipe [0121] 14 outer pipe [0122] 15 insulation cap [0123] 16 flow space [0124] 17 gas nozzle carrier [0125] 18 milling tool