FR3014714A1 - MANUFACTURED ARC SUCTION TORCH WITH IMPROVED SMOKE EXTRACTION - Google Patents

Abstract

The invention relates to a manual arc welding torch comprising a torch body (1) comprising a handling handle (2), a bent tubular portion (5) attached to said torch body (1), a sensor fumes (22) fixed to said bent tubular portion (5), the flue gas sensor (22) comprising one or more openings (25) distributed around its periphery, a welding nozzle (6) attached to the flue gas sensor (22) . According to the invention, the torch further comprises a first screen (30) arranged between the opening (s) (25) of the smoke sensor (22) and the welding nozzle (6).

Description

The invention relates to a manual arc welding torch, preferably of the MIG / MAG type, with improved suction of the fumes emitted during a welding operation, in particular welding in position and / or with high arc intensity. . In manual MIG / MAG welding, a welder usually holds by hand a manual welding torch which is used to make the desired weld seam (s). In order to comply with certain regulations or standards which stipulate that, if it is not possible to suppress emissions in the form of gases, vapors, aerosols of solid or liquid particles, substances that are unhealthy, uncomfortable or dangerous to the health of workers, they must be captured as and when they are produced, as close to their source of emission and as efficiently as possible, some manual torches are equipped with a conduit or the like of flue gas that is connected fluidly to a central vacuum so as to allow welding fumes to be sucked by means of a flue gas sensor, assembled to a bent portion of the welding torch, which is also often used as a nozzle holder.

These fumes are sucked by the smoke sensor carrying the nozzle, then channeled in the bent portion, in the torch handle, in a sheath, and finally in a connector designed for connection with a welding generator and a central unit. aspiration. However, the suction efficiency is no longer optimal when the welder must intervene in a tight weld zone, such as a deep joint or in a closed angle, or perform a welding in position such as a vertical welding up or down. ceiling. Indeed, in such cases, the suction speed of the gas also causes a portion of the shielding gas distributed by the nozzle, which leads to a degradation of the quality of the weld. To overcome this problem, it is necessary to adjust the suction flow, in particular to reduce it to reduce or at least greatly limit the amount of shielding gas unexpectedly sucked together with the welding fumes. To do this, the operator can intervene on the mechanical adjustment of the handle of the torch to reduce the depression at the sensor, or a remote electric control associated with the central vacuum system. It is also known to fix a skirt upstream of the flue gas sensor, the skirt forming a sleeve around the flue gas sensor to focus the suction flow towards the electric arc and suck the fumes before they have left the zone. capture. These solutions are described in particular in documents EP-A-2556913 and EP-A2556914. However, existing solutions are not fully satisfactory. Indeed, problems arise in particular when welding in position, such as a rising vertical position or ceiling. Indeed, these particular configurations cause many metal projections, as well as fallout drops of unstable metal from the weld bead, the metal can be melted or in the solid state. Because of the gravity and / or the suction, metal particles at high temperature, or even incandescent, penetrate into the openings of the flue gas sensor and are then driven upstream of the sensor into the suction circuit. This phenomenon is accentuated when using a skirt as described in EP-A-2556914, the latter behaving like a funnel capturing the projections. In addition to a degradation of the suction flow over time by accumulation of molten dusts and metal drops in the suction circuit, it follows an abnormal wear of the components of the torch and the suction circuit, particularly the components of electrical insulating material. Solutions of fabricating the components in high temperature resistant materials or protecting them with a specific coating unacceptably increase the cost of the torch. Existing solutions also become ineffective in the case of emissions of large volumes of fumes, as is the case in MIG welding with cored wire, particularly at high intensity, that is to say up to 450 A, or even 500 A. The fumes then rise rapidly due to the natural ascending convection of the air column and hot gas formed around the electric arc. If the suction flow is too focused towards the nozzle, a large part of the smoke escapes there. If the welder increases the suction flow, a stiffened air flow is formed around the nozzle, causing the shielding gas, which causes blisters in the bead. From there, the problem that arises is to overcome all or some of the aforementioned drawbacks, notably by proposing a manual arc welding torch offering improved welding fume extraction performance, both in welding configuration and closed angle, in position and / or at high intensity, as well as effective protection of the components of the torch and the associated suction circuit against the metal projections generated by the welding process.

The solution of the invention is a manual arc welding torch comprising: - a torch body comprising a handling handle, - a bent tubular portion attached to said torch body, - a flue gas sensor attached to said portion tubular bent, the smoke sensor comprising one or more openings distributed around its periphery, and a welding nozzle attached to the smoke sensor, characterized in that it further comprises a first screen arranged between the or the openings of the sensor of fumes and the welding nozzle. Depending on the case, the invention may include one or more of the following technical features: the welding nozzle comprises an upstream end attached to a downstream end of the smoke sensor, the first screen being arranged around said upstream end of the smoke detector; welding nozzle and / or around said downstream end of the flue gas sensor. - the first screen is attached to the smoke sensor. - The welding nozzle comprises a downstream end, the first screen being fixed at a distance of between 10 and 100 mm, preferably between 20 and 80 mm, of said end. the first screen has a generally annular shape. the welding nozzle comprises a first external surface and the smoke sensor comprises a second external surface, the first screen extending substantially radially away from the first external surface of the welding nozzle and / or the second external surface; smoke sensor. the upstream portion of the welding nozzle is generally cylindrical in shape, the first screen having an external diameter greater than the external diameter of said upstream portion by a multiplying factor greater than or equal to 1.5, preferably greater than or equal to 2; , more preferably greater than or equal to 3. - the first screen comprises a downstream face arranged facing the welding nozzle and an upstream face arranged facing the smoke sensor, the downstream face and / or the upstream face having a shape general frustoconical convergent or divergent towards the welding nozzle. the bent tubular portion comprises a third external surface, a second screen being arranged between the smoke sensor and the bent tubular portion and extending substantially radially away from the third external surface of the bent tubular portion and / or from the second outer surface of the flue gas sensor. the second screen comprises a downstream face arranged facing the bent portion and having a generally frustoconical divergent shape towards the welding nozzle. the torch body comprises a flue gas duct passing through said torch body; the angled tubular portion comprises a first internal passage in fluid communication with the flue gas discharge duct; the flue gas sensor comprising a second passage; internal device in fluid communication with the flue gas discharge duct, the flue gas sensor comprising a first peripheral wall and one or more openings provided in said first peripheral wall so as to put said first internal passageway in fluid communication with the outside of the flange. the torch; the welding nozzle comprises a first internal duct coming to connect to a second internal duct of the torch body, said first and second ducts serving to convey at least one welding fuse wire and the shielding gas. the bent tubular portion comprises a first internal duct, arranged in its second internal passage, coming to be connected to a second internal duct of the torch body, said first and second ducts serving to convey at least one welding fuse wire, preferably a welding wire and shielding gas. - The first inner duct passes axially substantially through the bent tubular portion and is also bent, that is to say that they are approximately concentric and coaxial (although their axes are curved). - The smoke sensor comprises several openings, such as gills, distributed around its periphery. the smoke sensor has a generally tubular shape. the torch is of the MIG / MAG type. - the welding fuse wire is a solid wire or a cored wire. the handle of the torch is shaped and dimensioned so that it can be held in the hand by a welding operator, in particular a welder provided with protective gloves. the torch body comprises an electric control trigger and / or a remote control member, the electric control trigger serving to trigger the welding cycle organized or programmed in the welding generator, in particular, the electrical power (intensity , voltage), controlling the speed of the welding fuse wire, and controlling the shielding gas of the electric arc. - The remote control member allows remote adjustment of one or more welding parameters, including voltage, intensity, wire speed, program number ...

According to another aspect, the invention relates to a first or second screen of a torch according to the invention. The invention also relates to a welding installation comprising a welding current generator, a wire feeder carrying a welding wire coil, a gas source and an arc welding torch according to one of the preceding claims.

Of course, the arc welding torch is connected in a conventional manner to the generator, the reel and the gas source via a bundle of electrical cables and pipes. Furthermore, the invention also relates to a method of electric arc welding, in particular MIG / MAG welding, using a torch or a welding installation according to the invention. Preferably, the method according to the invention is operated at high arc intensity, up to 450 A, or even 500 A, preferably at least 300 A, and / or in position, in particular in a rising vertical position or at the ceiling. . The invention will now be described in more detail with reference to the appended figures among which: FIG. 1 represents an embodiment of a welding torch according to the prior art, that is to say without implementation According to the invention, FIG. 2 represents a partial sectional view of the torch illustrated in FIG. 1; FIG. 3 illustrates a first embodiment of a welding torch as illustrated in FIG. FIG. 4 illustrates a second embodiment of the invention, and FIG. 5 illustrates a third embodiment of the invention.

FIG. 1 represents an embodiment of a manual arc welding torch according to the prior art, for example a MIG welding torch (for Metal Inert Gas), that is to say welding with supply of metal in the form of a fusible wire 11 and introduction of an inert gaseous protection based on one or more gases, such as argon, helium and their mixtures, or MAG (for Metal Active Gas) with an active gas shield based on CO2 or a mixture of argon with CO2, the gases being in variable proportions depending on the metals to be welded. This MIG / MAG torch comprises a torch body 1 provided with a handle or handle 2 that the operator holds by hand during the actual welding operation, as well as an electric trigger 3 and A remote control unit 4. The electric control trigger 3 is arranged on an electrical circuit connecting the torch to a welding current generator, and its activation by the operator allows the passage of the electric current used to melting the fusible welding wire 11 at the nozzle 6 fitted to the torch, as explained below. Moreover, the remote control member 4 allows the operator to remotely control welding equipment, in particular the welding current generator, or even the wire reel, so as to be able to adjust one or more parameters of the welding device. welding without having to move up to these equipment, for example parameters of the type voltage, current, speed of wire ... The torch also comprises a smoke sensor 22 mechanically connected by its upstream end 22a to the downstream end 51D of a bent tubular portion 5, which is connected itself, by its upstream end 5a, to the torch body 1. Figure 2 shows that the downstream end of the bent tubular portion 5 is connected to the sensor. The flue gas sensor 22 and the welding nozzle 6 may thus comprise, at its fixing site, threading means such as complementary threaded portions or means for engaging them. ratchet of the flue gas sensor 22 in or around the welding nozzle 6. The flue gas sensor 22 comprises a first internal passage 13 in fluid communication, via the second internal passage 26 of the bent tubular portion 5, with an evacuation duct fumes 9 passing through the torch body 1 so as to operate a suction of all or part of the fumes and gases emitted during the welding operation, in particular due to the melting of the fuse wire 11 by the electric arc. The fumes emitted during welding are in fact sucked in and enter the first internal passage 13 and then the second internal passage 26, via one or more openings 25, such as gills, arranged through the wall of the smoke sensor 22. These openings 25 in fact make it possible to communicate the inside of the smoke sensor 22, that is to say the first internal passage 13, with the ambient atmosphere which is charged with fumes during welding. The evacuation of the fumes is then done through the internal channel of the torch body and then through the sheath 24.

Furthermore, the flue gas sensor 22 carries, at its downstream end 22b, a welding nozzle 6 through which the fuse wire 11 leaves and which also makes it possible to distribute the shielding gas in the welding zone so as to protect it from any contamination by atmospheric impurities, such as oxygen, nitrogen or water vapor, for example. To do this, the tubular portion 5 covers a first internal duct 12 (lance duct) coming to connect to a second internal duct 10 (lance connector) of the torch body 1 which serve to convey the fuse wire 11 and the gas of protection in the nozzle 6. The first inner conduit 12 and second inner conduit 10 also serve to route the electric current to a contact tube 27 held in the nozzle 6 by a support 28 of the contact tube. These elements are kept isolated from the nozzle 6 by an insulating diffuser 29. The fusible wire 11 actually crosses the contact tube 27 and is then gradually melted by the electric arc which is created at the free end of the fuse wire, during the welding. Typically, the fusible wire 11 comes from a wire reel (not shown) and the gas is from a gas source (not shown), such as a gas cylinder, which are generally connected to one and the other to the welding current generator. A suction device (not shown), such as a high-vacuum turbine, connected to the torch body 1 by a suction duct 24, makes it possible to extract the fumes via the sensor 22, then the internal passage 13 of the portion tubular 5 bent towards a discharge duct 9 arranged in the body 1 of the torch.

According to the invention, and as illustrated in FIGS. 3 to 5, a first screen 30 is arranged between the flue gas sensor 22 and the welding nozzle 6. This positioning of the first screen 30 makes it possible to strongly limit or even prevent the introduction of particles and / or drops of molten metal or metal dusts in the smoke sensor 22. It furthermore has the advantage of widening the smoke collection zone accessible to the sensor 2 with respect to the torches of the prior art, all other conditions being equal, in particular with comparable suction flow rate. Fumes far from the welding zone can thus be attracted more effectively by the suction flow. Preferably, the first screen 30 has a generally annular shape, that is to say that the first screen 30 is a symmetry piece of revolution hollowed in its center so as to release a passage to arrange at least a portion of the nozzle 6 and / or the sensor 22.

Advantageously, the first screen 30 is arranged coaxially with the nozzle 6 and / or the sensor 22. In other words, the axis of symmetry of the first screen 30 is aligned, i. e coincides with the axis of symmetry of the nozzle 6 and / or the sensor 22. Preferably, the periphery and / or the central recess of the first screen 30 are circular in shape. The first screen 30 advantageously extends around the entire periphery of the welding nozzle 6 and / or the smoke sensor 22, so as to form a screen for the projections coming from the welding zone, in particular in the case of a welding performed in position. In the context of the invention, the welding nozzle 6 comprises an upstream end 6a attached to a downstream end 22b of the flue gas sensor 22, as can be seen more clearly in FIG. 2.

According to a preferred embodiment of the invention, the first screen 30 is arranged around said upstream end 6a of the welding nozzle 6 and / or around said downstream end 22b of the smoke sensor 22. According to a particular embodiment of the invention, the first screen 30 can be arranged at the site of attachment of the welding nozzle 6 to the flue gas sensor 22.

Preferably, the first screen 30 is fixed on the flue gas sensor 22. Advantageously, the first screen 30 and the flue gas sensor 22 comprise mutual fixing means that can be dismantled or not. These fixing means may comprise threading means such as complementary threaded portions arranged on the first screen 30 and the sensor 22, or latching means of the first screen 30 with the smoke sensor 22. These fixing means are particularly advantageous. since they allow a removable attachment of the sensor and the deflector and a mounting of the baffle once the other elements of the torch assembled. According to an alternative embodiment, the first screen 30 can be fitted, brazed or glued around the flue gas sensor 22.

Preferably, the first screen 30 is fixed at a distance of between 10 and 100 mm, preferably between 20 and 80 mm, from the end 6b of the welding nozzle 6. Such distance ranges make it possible to reinforce the suction , while avoiding that the first screen 30 causes a stagnation of the fumes above the welding zone. According to the invention, the first screen 30 comprises a downstream face 30b arranged facing the welding nozzle 6 and an upstream face 30a arranged facing the smoke sensor 22, said downstream and upstream faces 30a, 30b not being necessarily planes but can take any geometry suitable for effective protection of the flue gas sensor 22 and / or enhanced suction fumes remote from the body 1 torch. Preferably, the first screen 30 is a part of revolution, the downstream and upstream faces 30a, 30b being surfaces of revolution that can be generated by the rotation of a generator around a fixed axis, here the axis of symmetry the first screen 30, and limiting the first screen 30. Preferably, the first screen 30 has a generally frustoconical general shape. More specifically, the generatrices of the downstream and / or upstream faces 30a, 30b may be rectilinear or comprise curvilinear portions, preferably substantially concave or convex portions. Advantageously, the generatrices of the downstream and / or upstream faces 30a, 30b generally form an angle of between 30 and 60 ° with respect to the axis of symmetry of the nozzle 6, substantially coinciding with the axis of symmetry of the first screen 30. Advantageously, and in particular in the case of a welding performed on a workpiece 40 in a rising vertical position, as illustrated in FIG. 3, the downstream face 30b is of substantially frustoconical shape converging towards the welding nozzle 6. This allows not favoring the accumulation of projections on the first screen 30. Advantageously, and particularly in the case of a welding operated flat on a workpiece 40 to be welded with high current, as shown in Figure 4, the upstream face 30a is of substantially frusto-conical shape towards the smoke sensor 22. Advantageously, the upstream face 30a is of generatrix comprising a convex curvilinear portion. This form is particularly well adapted to guide the fumes that have moved above the welding nozzle 6 towards the smoke sensor 2. In the context of the invention, the welding nozzle 6 comprises a first external surface 6c and the smoke sensor 22 comprises a second external surface 22c.

Advantageously, and in order to ensure an effective protection of the flue gas sensor 22 and a better aspiration of the fumes remote from said sensor 22, the first screen 30 extends substantially radially away from the first outer surface 6c of the nozzle welding device 6 and / or the second external surface 22c of the flue gas sensor 22. Preferably, the first screen 30 has an outside diameter greater than the outside diameter of said upstream portion 6a by a multiplying factor greater than or equal to 1.5, preferably greater than or equal to 2, more preferably greater than or equal to 3. The first screen 30 may thus have an outer diameter of about 20 to 80 mm, preferably 25 to 60 mm. The first screen 30 may be made of a plastic, ceramic or metallic material. The first screen 30 may also be made of any electrically insulating material. According to a particular embodiment of the invention, in addition to the first screen 30, a second screen 31 is arranged between the flue gas sensor 22 and the bent tubular portion 5. An example of this embodiment is illustrated in FIG. welding torch then in the configuration of welding on the ceiling. Preferably, the first screen 31 has a generally annular shape, that is to say that the first screen 31 is a symmetry piece of revolution hollowed in its center so as to release a passage to arrange at least a portion of the bent tubular portion 5 and / or the sensor 22. Advantageously, the second screen 31 is arranged coaxially with the nozzle 6 and / or the sensor 22. In other words, the axis of symmetry of the second screen 31 is aligned, i . e coincides with the axis of symmetry of the nozzle 6 and / or the sensor 22. Preferably, the periphery and / or the central recess of the second screen 31 are circular in shape. The first screen 31 preferably extends around the entire periphery of the tubular portion and / or the flue gas sensor 22, so as to effectively guide the flue gas 42 to the sensor 22.

In the context of the invention, the bent tubular portion 5 comprises a downstream end 51D attached to the upstream end 22a of the flue gas sensor 22, as can be seen more clearly in FIG. 2. According to a preferred embodiment of the invention , the second screen 31 is arranged around said upstream end 22a of the flue gas sensor 22 and / or around said downstream end 51D of the tubular portion 5. According to one particular embodiment of the invention, the second screen 31 is arranged at the location of attachment of the bent tubular portion 5 to the flue gas sensor 22. Advantageously, the second screen 31 comprises means for attachment to the flue gas sensor 22 and / or to the bent portion 5. These fixing means may comprise threading means such as complementary threaded portions arranged on the second screen 31 and the sensor 22 and / or the portion 5, or latching means of the second screen 31 with the smoke sensor 22 and / or the tubular portion 5. According to an alternative embodiment, the second screen 31 may be fitted around the smoke sensor 22 and / or the bent tubular portion 5. The first and second screens 30, 31 may optionally be solidary and / or formed of the same block. Preferably, the second screen 31 extends substantially radially away from a third external surface 5c of the bent tubular portion 5 and / or from the second external surface 22c of the smoke sensor 22. Advantageously, the second screen 31 comprises a downstream face 3 1b arranged facing the flue gas sensor 22 and having a generally frustoconical shape, preferably a frustoconical shape diverging towards the flue gas sensor 22, as illustrated in FIG. 5. As seen in FIG. 5 the first screen 30 provides protection for the sensor 22 and the suction circuit connected to said sensor 22 vis-à-vis projections of molten metal 41 and metal dust from the welding zone operated on the workpiece 40. in addition, the second screen 31 improves the collection of fumes 42 by the suction flow produced by the sensor 22. The combination of the first and second screens 30, 31 is therefore particular effective in improving torch suction performance.

It should be noted that the second screen 31 may have other structural characteristics identical to those mentioned for the first screen 30, they are not listed again for the sake of brevity. Preferably, for reasons of reducing the production cost of the components of the torch, the first and second screens 30, 31 are parts having an identical geometry. According to the torch model, the cooling is: - either of the natural or air type, that is to say that the calories released by the Joule effect of the connections and power cables and the calories generated by the arc, are evacuated by convection, but, depending on the case, the suction flow flowing in the elbow and the handle of the torch can also have a cooling action of the tool held in the hand of the operator . - of the type cooled with water. In this case, a water cooling unit (pump + exchanger) feeds a specific circuit of the torch to cool the power cable, the torch lance, and the wear parts. The torch of the invention is particularly suitable for any manual arc welding process, in particular for MIG / 1 / 4AG welding, preferably operated in position and / or at high intensity.

Claims (13)

REVENDICATIONS1. Manual arc welding torch comprising: - a torch body (1) comprising a handling handle (2), - a bent tubular portion (5) attached to said torch body (1), - a smoke sensor (22) attached to said angled tubular portion (5), the flue gas sensor (22) including one or more openings (25) distributed around its periphery, and - a welding nozzle (6) attached to the flue gas sensor (22). ), characterized in that it further comprises a first screen (30) arranged between the opening or openings (25) of the flue gas sensor (22) and the welding nozzle (6). 2. Torch according to the preceding claim, characterized in that the welding nozzle (6) comprises an upstream end (6a) attached to a downstream end (22b) of the flue gas sensor (22), the first screen (30) being arranged around said upstream end (6a) of the welding nozzle (6) and / or around said downstream end (22b) of the flue gas sensor (22). 3. Torch according to one of the preceding claims, characterized in that the first screen (30) is fixed on the smoke sensor (22). 4. Torch according to one of the preceding claims, characterized in that the welding nozzle (6) comprises a downstream end (6b), the first screen (30) being fixed at a distance of between 10 and 100 mm, preferably between 20 and 80 mm, of said end (6b). 5. Torch according to one of the preceding claims, characterized in that the first screen (30) has a generally annular shape. 6. Torch according to one of the preceding claims, characterized in that the welding nozzle (6) comprises a first outer surface (6c) and the smoke sensor (22) comprises a second outer surface (22c), the first screen (30) extending substantially remotely from the first outer surface (6c) of the welding nozzle (6) and / or the second outer surface (22c) of the flue gas sensor (22). 7. Torch according to one of the preceding claims, characterized in that the upstream portion (6a) of the welding nozzle (6) is generally cylindrical, the first screen (30) having an outer diameter greater than the outer diameter of said upstream portion (6a) of a multiplying factor greater than or equal to 1.5, preferably greater than or equal to 2, more preferably greater than or equal to 3. 8. Torch according to one of the preceding claims, characterized in that the first screen (30) comprises a downstream face (30b) arranged facing the welding nozzle (6) and an upstream face (30a) arranged opposite the smoke sensor (22), the downstream face (30b) and / or the upstream face (30a) having a frustoconical general shape convergent or diverging towards the welding nozzle (6). 9. Torch according to one of the preceding claims, characterized in that the bent tubular portion (5) comprises a third outer surface (5c), a second screen (31) being arranged between the flue gas sensor (22) and the portion tubular bent (5) and extending substantially radially away from the third outer surface (5c) of the bent tubular portion (5) and / or from the second outer surface (22c) of the flue gas sensor (22). 10. Torch according to one of the preceding claims, characterized in that the second screen (31) comprises a downstream face (3 lb) arranged opposite the bent portion (5) and having a generally frustoconical divergent shape towards the nozzle of welding (6). 11. First or second screen of a torch according to one of the preceding claims. 12. Welding installation comprising a welding current generator, MIG / MAG, a wire feeder carrying a wire coil, a source of shielding gas, and an arc welding torch according to one of the preceding claims. . 13. A method of manual arc welding, in particular MIG / MAG welding, using a torch according to one of claims 1 to 10 held by hand by an operator and / or a welding installation according to the claim 12.