DE102020004092A1 - Welding torch nozzle, welding torch and process for gas-shielded welding - Google Patents

Abstract

The invention relates to a welding torch nozzle (1) for inert gas welding torches, having an at least partially essentially cylindrical housing (2), an electrode (9) inside the housing (2), a rear end section (3) to which inert gas can be supplied, and a front end section (5) at which the protective gas can be discharged, a first channel (13) being provided in the housing (2), which is connected to a protective gas supply (9) for the passage of protective gas from the rear end section (3 ) to the front end section (5), with an extraction device being arranged in the housing (2), through which fumes produced during welding are extracted at the front end section (5) and can be discharged through the housing (2). The invention also relates to a welding torch and a method for gas-shielded welding using a welding torch, with the fumes produced during welding being extracted at a front end section (5) of a welding torch nozzle (1) and through a housing (2) of the welding torch nozzle (1) from a front end section (5) are derived to a rear end portion (3).

Description

The invention relates to a welding torch nozzle for a gas-shielded welding torch according to the preamble of claim 1 and a welding torch and a method for gas-shielded welding.

In arc welding, an electric arc is used as a heat source to melt the components to be joined at their respective joints. A protective gas escaping through the welding torch also serves to shield the electrode and the melted joints from the ambient air in order to avoid possible chemical reactions on the workpiece.

However, due to the high temperatures in the arc, the sublimation of the metals of the workpiece to be welded is promoted, so that fumes are produced which can be harmful to the health of the welder.

Welding torches for gas-shielded arc welding are therefore known in the prior art, which have external extraction devices for extracting the fumes produced during welding. However, the known welding torches with external suction devices, e.g. H. Extraction devices that are designed to extract exhaust gases outside or externally of the protective gas bell, designed in such a way that the smoke gases reach the surrounding atmosphere after penetrating the protective gas cover and are then partially extracted there. However, a certain proportion of the exhaust gases already in the atmosphere remains in the atmosphere and is not captured by the extraction device, which represents a not inconsiderable health risk for a welder who then inhales these exhaust gases with the ambient air.

Therefore, the present invention is based on the object of providing a welding torch nozzle, a welding torch and a method for gas-shielded welding, which allow fumes generated during welding to be extracted and discharged more completely before they enter the surrounding atmosphere and can lead to environmental pollution or health risks.

This object is achieved according to the invention by a welding torch nozzle for an inert gas welding torch having the features of claim 1, a welding torch having the features of claim 14 and a method for inert gas welding having the features of claim 15. Advantageous developments of the invention are specified in the respective dependent claims.

According to the invention, a welding torch nozzle for inert gas welding torches is provided, with an essentially cylindrical housing, an electrode inside the housing, a rear end section to which inert gas can be supplied, and a front end section to which the inert gas can be discharged, wherein in the housing a first duct is provided, which can be connected to a first protective gas feed for the passage of protective gas from the rear end section to the front end section, with a suction device being arranged in the housing, through which smoke gases produced during welding are sucked off at the front end section and through the housing can be derived. Due to the configuration of the welding torch nozzle according to the invention, exhaust gases or metal vapors produced during welding can be sucked off directly where they are produced, before they penetrate the protective gas cover and get into the atmosphere. This avoids the pollution of the ambient air caused by this, in particular in the work environment of a welder and the health risks associated therewith.

According to a preferred embodiment, the suction device is a substantially ring-shaped second channel, which extends from the front end section to the rear end section. Thus, the exhaust gases can internally, i. H. be extracted and discharged through the housing of the welding torch nozzle directly inside the shielding gas bell.

According to a further preferred embodiment, the suction device, in particular the essentially second ring-shaped channel, can be connected to a suction device. A suction device is to be understood, for example, as any mobile or stationary commercially available smoke extraction device.

According to yet another preferred embodiment, the electrode is arranged centrally in the housing, with the essentially annular second channel concentrically surrounding the electrode. This configuration makes it possible to implement exhaust gas extraction and evacuation directly where the exhaust gases are generated during welding, without destroying the shielding gas cup.

Preferably, at least one third essentially ring-shaped channel is provided in the housing, which can be connected to a second protective gas feed line for conducting protective gas from the rear end section to the front end section, the third essentially ring-shaped channel concentrically surrounding the first essentially ring-shaped channel. By providing two protective gas channels, the protective gas coverage is advantageously improved.

In addition, it is advantageous if the first essentially ring-shaped channel and the third essentially ring-shaped channel have different widths from one another. In this way, different flow speeds can be realized in the two protective gas channels in a simple mechanical manner without complex electronic controls of the protective gas volume flow, in order to achieve reliable and complete protective gas coverage.

According to still another preferred embodiment, the thickness of an outer wall of the housing is tapered from the rear end portion toward the front end portion. In this way, too, the protective gas volume flow can be mechanically influenced in order to develop a desired flow rate or characteristic.

The walls surrounding the first, second and third substantially annular channels may end flush at the front end portion. Alternatively, the walls surrounding the first, second and third substantially annular channel may be tapered at the front end portion, with the wall of the third substantially annular channel having a shorter length than the wall of the first substantially annular channel. While the flush design of the channel walls at the front end section requires little structural effort, the beveled design of the front end section offers the advantage that a change of position is simplified when machining a workpiece.

The housing is particularly preferably provided with a cooling circuit integrated therein, in particular with a cooling channel running around the housing wall.

According to yet another preferred embodiment, the protective gas flow that can be guided through the first essentially annular channel and the protective gas flow that can be guided through the third essentially ring-shaped channel can be regulated by a control device, in particular in such a way that the protective gas flow that can be guided through the first essentially annular channel corresponds to the through the third substantially ring-shaped channel conductive inert gas stream has different flow rates. The different flow speeds ensure that the shielding gas cover is formed reliably and stably. In particular, this leads to a differing rigidity of the protective gas jacket or the protective gas bell.

The flow rate in the first essentially ring-shaped channel and the flow rate in the third essentially ring-shaped channel can preferably be set separately, in particular via respective connections on a manometer. As already mentioned above, different flow speeds of the protective gas streams can be achieved in the two protective gas channels in order to ensure stable protective gas coverage.

Yet another preferred embodiment provides for the housing to be designed in multiple parts, with the housing parts being able to be connected to one another in a form-fitting manner, in particular being able to be screwed together. The multi-part design of the housing offers the advantage that it can be replaced or repaired quickly in the event of wear or defects. Alternatively, however, the housing can also be designed or manufactured integrally, in particular in one piece.

Furthermore, according to the invention, a welding torch with a welding torch nozzle as mentioned above is provided.

According to one embodiment, the welding torch is designed as a welding robot. Alternatively, the welding torch may be a device manually operated by a welder, or it may be an automated device.

Furthermore, according to the invention, there is provided a method for arc welding using a welding torch, wherein fumes produced during welding are sucked off at a front end portion of a welding torch nozzle as described above and discharged through the housing of the welding torch nozzle from the front end portion to the rear end portion.

• 1A, 1B jeweilige Schnittansichten einer Schweißbrennerdüse gemäß einer Ausführungsform der Erfindung zeigen;
• 2 eine vergrößerte Schnittansicht des vorderen Endabschnitts einer Schweißbrennerdüse gemäß einer Ausführungsform der Erfindung zeigt;
• 3 schematisch die an der in 2 dargestellten Schweißbrennerdüse beim Schweißen entstehende Schutzgasabdeckung und den Strömungsverlauf der abgesaugten Metalldämpfe bzw. Abgase an der Schweißnaht zeigt;
• 4 eine Schweißanlage gemäß einer Ausführungsform der Erfindung zeigt; und
• 5 eine Draufsicht auf eine Anbindungseinheit zur Anbindung der Schweißbrennerdüse an verschiedene Medien gemäß einer Ausführungsform der Erfindung zeigt.

The invention is described below with reference to the drawing, in which

• 1A , 1B show respective sectional views of a welding torch nozzle according to an embodiment of the invention;
• 2 Fig. 12 shows an enlarged sectional view of the front end portion of a welding torch nozzle according to an embodiment of the invention;
• 3 schematically the at the in 2 shown welding torch nozzle resulting shielding gas cover and the shows the course of flow of the extracted metal vapors or exhaust gases at the weld seam;
• 4 shows a welding system according to an embodiment of the invention; and
• 5 shows a top view of a connection unit for connecting the welding torch nozzle to different media according to an embodiment of the invention.

1A and 1B show a welding torch nozzle 1 in sectional view according to an embodiment of the invention, wherein 1A shows the welding torch nozzle 1 in a partially assembled state, and 1B shows the welding torch nozzle 1 disassembled into individual parts.

First of all, it should be noted that in the context of the described embodiments, inert gas welding in the sense of DIN 8593-6 is to be understood as all welding types and devices that work by means of an electric arc as a heat source for melting the material to be processed, which is located between an electrode and the conductive material to be processed burns. This includes, for example, metal inert gas welding (MAG), which includes inert gas welding (MIG) and metal active gas welding (MAG), and in which processes the electrode is melted off during welding, as well as tungsten inert gas welding (TIG) with a non-consumable electrode. Also included is orbital welding and plasma welding.

As in 1A As can be seen, three housing sections or housing parts 2', 2'', 2''' of the housing 2 of the welding torch nozzle 1 are shown in the assembled state, and a fourth housing part 2'''', which is only shown in side view, is shown as Part or module shown separately. The fourth housing part 2'''' represents the rear end section 3 or the head part of the welding torch nozzle 1 and includes the media connection or the media connections via which the media supply, ie the supply of protective gas and the supply of electrical energy to the electrode and the Supply of cooling water for internal cooling takes place. The head part or the fourth housing part 2'''' has a connecting piece 4 at its upper end 7, via which the welding torch nozzle 1 can be connected to a torch neck (not shown). It is noted that the constructive installation of all necessary media (electricity, protective gas, suction, water) in the interior of the housing 2 excludes the susceptibility to faults and possible operating errors. A malfunction due to improper operation (e.g. collision with workpiece or welding system, destruction of transport lines) cannot occur with this embodiment. In addition, there is sufficient external protection.

The first housing part 2', on the other hand, represents the front end section 5 of the welding torch nozzle 1, at the lower end 6 of which the shielding gas that can be fed in via the media supply and the electrode exit. In the first housing part 2', a central cavity 8 is formed by a first concentric wall 10, in which a central electrode 9 is arranged, which is designed here as a meltable electrode, i. H. here, a feedable electrode wire is used as the electrode. Formed between the inside 11 of the first concentric wall 10 and the central electrode 9 is an annular channel which concentrically surrounds the electrode 9 and is referred to here as the second channel 12 and which serves as a suction device. Here, metal vapors and other exhaust gases that are produced on the workpiece during welding and that can be produced by the welding process are sucked in directly and discharged via the second channel 12 through the housing 2 of the welding torch nozzle 1 . It is therefore an internal extraction device or one integrated into the welding torch nozzle housing 2, by means of which the above-mentioned metal vapors and exhaust gases are already extracted at the point of origin inside the protective gas bell without destroying the protective gas bell, so that no metal vapor or exhaust gases can get into the atmosphere . This can effectively prevent the welder or other people in the vicinity of the welding device from being exposed to a health risk from inhaling the exhaust gases or metal vapors or from environmental damage caused by the exhaust gases or metal vapors. It has also been found that with direct extraction of the metal vapors at the point of origin within the protective gas bell, pore formation in the workpiece or at the weld point or weld seam can be avoided, which leads to a significant improvement in the physical properties of the welded connection.

Furthermore, a first channel 13 is provided in the first housing part 2', which is designed as an annular channel and can be connected to a first protective gas supply for conducting protective gas from the rear end section 3 to the front end section 5 of the welding torch nozzle 1. The first channel 13 is from surrounded by a third duct 14, which is also designed as a ring duct and which can be connected to a second protective gas feed for conducting protective gas from the rear end section 3 to the front end section 5 of the welding torch nozzle 1, where it exits from the welding torch nozzle 1 during the welding process.

As can be seen here, the third channel 14 forms the outer channel and the first channel 13 the inner channel in the welding torch nozzle 1. However, the third channel 14 is designed in such a way that it tapers towards the lower end 6 of the first housing part 2'. which can be achieved either by slightly sloping one of the two walls surrounding the annular channel or by reducing the wall thickness of at least one or both wall(s) surrounding the third channel 13 from the front end section 5 to the rear end section 3. Due to these geometries, the third channel 14 and the first channel 13 have different widths or flow cross sections, which means that different flow rates of the protective gas conducted through the two channels 13, 14 can be achieved, which results in reliable and complete protective gas coverage during welding. For example, a protective gas flooding of 5 l/min can be realized in the inner first channel 13 and a protective gas flooding of 20 l/min in the outer third channel 14, which leads to a reliable and stable protective gas covering during welding. However, should a fault occur so that the shielding gas cover becomes unstable during welding and exhaust gases or metal vapor nevertheless escape into the surrounding atmosphere, an advantageous embodiment provides that in this case a corresponding warning signal, for example acoustic or visual, is issued.

It can also be seen here that the walls surrounding the first, second and third essentially ring-shaped ducts 12, 13, 14 are beveled at the front end section, so that the front end section 5 of the welding torch nozzle 1 has a tip 15 towards the center, which is achieved as a result is that the wall of the third substantially annular channel 14 has a smaller length than the wall of the first substantially annular channel 13. It is noted that the shape of the first, second and third channels 12, 13, 14 can also have a different shape can have. They do not necessarily have to be ring-shaped, but can also have oval or elliptical shapes or any suitable shape deviating from a circular ring shape. Furthermore, it is noted that there can also be more than two channels for supplying the protective gas, for example three, four, five or more channels. The beveled design of the front end section 5 has the advantage that accessibility to the workpiece is improved. Alternatively, the respective walls can also be designed to end flush at the front end section 5 .

Furthermore, in 1A recognizable that in the second housing part 2" a circumferential cooling channel 16 is formed, which is supplied with coolant or cooling water via the median connection in the fourth housing part 2"''. On the third housing part 2"" are the transport channels 17 for the protective gas and for the suction of the exhaust gases as well as the central wire feed of the central electrode 9 can be seen.

2 12 is an enlarged sectional view of the front end portion 5 on the first body part 2' of a welding torch nozzle 1 according to an embodiment of the invention. In contrast to the in 1A and 1B In the embodiment described, the front end section 5 is not tapered here, but all the walls surrounding the first, second and third channel 12, 13, 14 end flush at the front end section 5. It is particularly evident here that the outer third channel 14 has a smaller flow cross section than the first inner channel 13.

3 shows schematically the at the in 2 Welding torch nozzle 1 shown during welding and the flow pattern of the extracted metal vapors or exhaust gases at the weld seam.

4 shows a welding system 17 for inert gas welding according to an embodiment of the invention, in which a welding torch nozzle 1, as in relation to the 1A , 1 B and 2 was explained, is used. The welding torch nozzle 1 can be connected to a conventional welding torch, for which purpose the nozzle shaft of the welding torch nozzle 1 is pushed onto the torch neck. The welding system 17 shown here also includes a welding robot 18, a suction unit 19 and a container 20 with protective gas. Filters can be used in the suction unit 19, which can be checked, for example, by means of a wear indicator.

5 shows a plan view of a connection unit 21 for connecting the welding torch nozzle 1 to the various media. The protective gas supply with protective gas from the in 4 The container 20 shown takes place via corresponding hoses and hose connection pieces provided on the connection unit 21 to the two channels 22, 22', with the channel 22 communicating with the inner first channel 13 in the welding torch nozzle 1 in the assembled state of the welding torch nozzle 1 and the channel 22' communicates with the outer third channel 14 in the welding torch nozzle 1. The innermost channel 23 communicates with the second channel 12 of the welding torch nozzle 1 and is via appropriate hoses and on the Connecting unit 21 provided connecting pieces 24 'with the suction unit 19 (see 4 ) connected.

In summary, it can be stated that according to the embodiments described above, the different flow speeds of the protective gas streams and the direct extraction of exhaust gases at the point of origin not only significantly reduce health risks for the welder, but also the quality of the weld bead is significantly improved, since pore formation is also prevented is significantly reduced.

Reference List

1

welding torch nozzle

2

Housing (2', 2'', 2'', 2'''' housing parts)

3

Rear End Section

4

fitting

5

Front End Section

6

Lower end of the first housing part

7

Upper end of the fourth housing part

8th

Central cavity in the first housing part

9

Central electrode

10

First concentric wall

11

Inside of the first concentric wall

12

Second channel / suction device

13

First channel

14

third channel

15

top

16

cooling channel

17

Inert gas welding system

18

welding robot

19

suction unit

20

Container with inert gas

21

connection unit

22, 22'

Inert gas supply channels in the connection unit

23

Exhaust duct in connection unit

24

hose fittings

Claims (15)

Welding torch nozzle (1) for inert gas welding torches, with an at least partially essentially cylindrical housing (2), an electrode inside the housing (2), a rear end section (3) to which inert gas can be supplied, and a front end section (5) , at which the protective gas can be discharged, a first channel (13) being provided in the housing (2), which is connected to a protective gas supply (9) for the passage of protective gas from the rear end section (3) to the front end section (5 ), characterized in that a suction device is arranged in the housing (2), through which fumes produced during welding are sucked off at the front end section (5) and can be discharged through the housing (2). Welding torch nozzle (1) according to claim 1 wherein the suction device is a substantially annular second channel (12) which extends from the front end portion (5) to the rear end portion (3). Welding torch nozzle (1) according to claim 2 , wherein the suction device, in particular the essentially second annular channel (12), can be connected to a suction device, in particular to a suction unit (19). Welding torch nozzle (1) according to claim 2 or 3 wherein the electrode (9) is arranged centrally in the housing (2), and wherein the substantially annular second channel (12) surrounds the electrode (9) concentrically. Welding torch nozzle (1) according to one of the preceding claims, wherein in the housing (2) at least a third substantially annular channel (14) is provided, which is connected to the protective gas supply for passing protective gas from the rear end section (3) to the front End portion (5), wherein the third substantially annular channel (14) concentrically surrounds the first substantially annular channel (13). Welding torch nozzle (1) according to any one of the preceding claims, wherein the first substantially annular channel (13) and the third substantially annular channel (14) have mutually different widths. A welding torch nozzle (1) according to any one of the preceding claims, wherein the thickness of an outer wall of the housing (2) is tapered from the rear end portion (3) to the front end portion (5). Welding torch nozzle (1) according to one of the preceding claims, in which the walls surrounding the first, second and third substantially annular channels (12, 13, 14) end flush at the front end portion (5). Welding torch nozzle (1) according to one of Claims 1 until 7 wherein the walls surrounding the first, second and third substantially annular channel (12, 13, 14) are tapered at the front end portion (5), the wall of the third substantially annular channel (14) having a length less than the wall of the first substantially annular channel (13). Welding torch nozzle (1) according to one of the preceding claims, wherein the housing (2) is provided with a cooling circuit integrated therein, in particular with a cooling duct (16) running around the housing wall. Welding torch nozzle (1) according to one of the preceding claims, wherein the flow of protective gas that can be guided through the first essentially ring-shaped channel (13) and the flow of protective gas that can be guided through the third essentially ring-shaped channel (14) can be regulated by a control device, in particular in such a way that the the flow rate of protective gas that can be conducted through the first essentially ring-shaped channel (13) differs from that of the flow rate of protective gas that can be led through the third essentially ring-shaped channel (14). Welding torch nozzle (1) according to one of Claims 1 until 10 , wherein the flow rate in the first essentially ring-shaped channel (13) and the flow rate in the third essentially ring-shaped channel (14) can be adjusted separately, in particular via respective connections on a manometer. Welding torch nozzle (1) according to one of the preceding claims, wherein the housing (2) is designed in multiple parts and the housing parts (2', 2'', 2''', 2'''') can be positively connected to one another, in particular screwed are. Welding torch with a welding torch nozzle (1) according to one of the preceding claims. Process for gas-shielded welding, characterized in that the fumes produced during welding are extracted at a front end section (5) of the welding torch nozzle (1) and passed through the housing (2) of the welding torch nozzle (1) from the front end section (5) to the rear end section (3 ) be derived.

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