EP0634887B1 - Transferred arc plasma torch - Google Patents

Transferred arc plasma torch Download PDF

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Publication number
EP0634887B1
EP0634887B1 EP94420206A EP94420206A EP0634887B1 EP 0634887 B1 EP0634887 B1 EP 0634887B1 EP 94420206 A EP94420206 A EP 94420206A EP 94420206 A EP94420206 A EP 94420206A EP 0634887 B1 EP0634887 B1 EP 0634887B1
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EP
European Patent Office
Prior art keywords
torch
plasma
cathode
anode
nozzle
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EP94420206A
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German (de)
French (fr)
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EP0634887A1 (en
Inventor
Frédéric Girard
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SOUDURE ASSISTANCE
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SOUDURE ASSISTANCE
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3421—Transferred arc or pilot arc mode
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3463—Oblique nozzles
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3468—Vortex generators

Definitions

  • the present invention relates to a welding torch or more particularly to reloading with transferred arc plasma, known under the abbreviation "PTA” (Plasma Transferred Arc).
  • the tip of the cathode is arranged on the main axis (longitudinal axis) of the torch, and positioned slightly behind the convergent nozzle-anode which surrounds it coaxially.
  • the plasma propagates and therefore leaves, in principle, along the main axis of the torch.
  • the geometric structure of the plasma generator device remains a structure parallel to the plasma, at least in the vicinity of the origin of the latter.
  • the plasma is born and begins to propagate in the axis of the negative electrode, even if this plasma is then deviated from said axis before the point of use, in particular by the oblique orientation of an outlet conduit and the position of the positive electrode constituted by the part to be recharged on which the transferred arc comes to loop.
  • the present invention therefore aims to improve a transferred plasma torch of the type concerned.
  • a transferred plasma torch comprising a nozzle-anode coaxially surrounding a cathode disposed along the longitudinal axis of the torch, and a channel of annular section formed between the nozzle-anode and the cathode and capable to be traversed by a flow of plasma gas, the torch being arranged to emit a plasma jet in a direction making a significant angle relative to the longitudinal axis of the torch, the latter being characterized in that it is provided , in addition to the initialization plasma gas circuit passing along the cathode, another circuit distinct from the previous one, and capable of being traversed by a directional plasma gas flow, the directional plasma gas circuit opening out, in a direction making a significant angle with the longitudinal axis of the torch, in a chamber or a conduit extending the annular section channel at the front of the torch and opening itself even outside by a lateral outlet orifice of the nozzle-anode, so that the plasma is created and propagates in a direction making
  • two separate circuits of plasma-generating gas are used, one for initialization traveling along the cathode, and the other directional arriving at the front of the torch in a direction forming a notable angle, which in a typical case reaches 90 °, with respect to the main axis of the torch (axis of the anode-cathode couple).
  • the use of a deflecting plasma gas stiffens the arc and gives much better results than in previous embodiments, which do not use a deflecting plasma gas and in which the plasma is emitted along the axis of the cathode and then deflected (as explained above).
  • the initial plasma plasma circuit and the directional plasma gas circuit are each provided with their own gas flow control means, so that the control of the plasma operating parameters results directly from the absolute settings and relative of the two plasma gas circuits.
  • the nozzle-anode is designed to be mounted on a base of a torch, comprising a cathode support block in which the cathode is held so as to be able to be mounted, axially adjusted and dismounted through the rear area of the torch.
  • This arrangement facilitates in particular the axial positioning adjustment of the cathode, which determines the characteristics of the plasma obtained.
  • the area made available by the change of direction of the plasma jet in the vicinity of the free end of the nozzle-anode is usable for accommodating in this area part of the cooling circuit by circulation of water.
  • the transferred arc plasma torch object of the invention, is particularly suitable for the reloading of small bores, with a flat melting bath, the internal cylindrical part to be coated having its axis disposed horizontally.
  • the torch which enters the bore during the reloading operation, is then with its horizontal main axis, and only the plasma jet is emitted vertically in a radial direction at the outlet of the lateral orifice practiced towards the free end of the anode nozzle.
  • the overall dimensions of the nozzle-anode must be adapted to the internal diameter of the bore of the part to be recharged, which in practice means that the nozzle-anode is long and of small diameter.
  • the advantage of such an arrangement is also to allow the use of a cathode of large longitudinal dimension, which can be conveniently mounted or dismounted by the base of the torch, for example to proceed with its sharpening.
  • FIG. 1 shows the front part of a welding torch or more particularly of reloading with transferred arc plasma, comprising a nozzle-anode 1 surrounding a cathode 2 arranged along the longitudinal axis 3 of the torch.
  • An annular section channel 4 is formed between the nozzle-anode 1 and the cathode 2.
  • the channel 4 is traversed by a first flow of plasma gas traveling along the cathode 2, as indicated by an arrow 5, this channel 4 belonging to a plasma gas circuit with the role of initializing the ionization of the gas and protecting the cathode 2.
  • the plasma initialization gas is distributed at the inlet of the convergent 6 of the nozzle-anode 1 by means of a ring 7 providing helical passages, which gives the gas a swirling movement capable of stabilizing the incipient discharge between the pointed end 8 of the cathode 2 and the anode 1.
  • the ring 7 also acts as a centering means for cathode 2 relative to the nozzle-anode 1.
  • the channel 4 is extended by a short convergent conduit 9 oriented along an axis 10 forming a significant angle A relative to the longitudinal axis 3 of the torch, and opening to the outside by an outlet orifice 11 located on the side wall of the nozzle-anode 1.
  • the angle A is equal to 90 °.
  • nozzle-anode 1 In the nozzle-anode 1 is formed, parallel to the channel 4 swept by the initial plasma gas, another channel 12 which has, at its front part, a right angle bend 13 with converging, opening out at the rear of the conduit 9, along the transverse axis 10.
  • the channel 12 is traversed, as indicated by an arrow 14, by a second flow of plasma gas, said directional plasma gas, thus traversing a circuit distinct from that of the initial plasma gas.
  • Each of these two independent circuits is provided with its own means (not shown) for controlling the plasma gas flow.
  • the plasma jet emitted at the anterior end of channel 4 is deflected by approximately 90 ° by the jet of directional plasma gas, of lower flow rate but of high speed, which is ejected by the converging elbow 13 and thus arrives in the duct 9 by imposing its own direction on the plasma flow.
  • the plasma created thus propagates, from the outset, in the direction of the axis 10, therefore substantially perpendicular to the axis 3 of the torch, to escape through the lateral outlet orifice 11.
  • the space made free by the change of direction of the plasma jet, in the vicinity of the end of the nozzle-anode, is used to pass the cooling water circuit 15 of the torch there, ensuring thus in this zone an energetic cooling.
  • FIG. 2 shows as a whole the torch equipped with the plasma generator device described above, in a particular embodiment inspired by French patent application FR-A-2672459 in the name of the Applicant.
  • the cathode 2 is held on its support block 17 by means of pliers 26.
  • a blind nut (not shown), screwed onto a thread 27 of the support block 17, gives very direct access to the cathode 2 which can thus be immobilized in the desired axial position.
  • This axial position of the cathode 2, as well as the independent adjustments of the flow rates of the initial plasma gas 5 and the directional plasma gas 14, constitute the three main elements for adjusting the torch.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Plasma Technology (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)

Abstract

This torch for welding, or more particularly for transferred-arc plasma resurfacing, comprises an anode nozzle (1) surrounding a cathode (2) arranged along a longitudinal axis (3). An initiation plasma-generating gas flow (5) passes through the channel (4) of annular cross-section made between the anode nozzle (1) and the cathode (2). In addition, a directional plasma-generating gas flow (14) passes through a separate circuit (12, 13) and generates a deflection effect, so that the plasma is created and is propagated in a direction (10) making a significant angle (A) with the longitudinal axis (3) of the torch, especially a direction perpendicular to the longitudinal axis (3) along which the cathode (2) is arranged, the plasma leaving through a lateral orifice (11). Such a torch is particularly suited to resurfacing (refilling) small bores. <IMAGE>

Description

La présente invention concerne une torche de soudage ou plus particulièrement de rechargement à plasma d'arc transféré, connue sous l'abréviation "PTA" (Plasma Transferred Arc).The present invention relates to a welding torch or more particularly to reloading with transferred arc plasma, known under the abbreviation "PTA" (Plasma Transferred Arc).

La génération d'un plasma d'arc électrique est un phénomène bien connu, utilisé depuis plusieurs dizaines d'années dans les torches de soudure ou de rechargement dites à plasma transféré. De nombreux modes de réalisation ont été proposés pour ces torches. Tous font appel à l'effet de pointe d'une cathode affûtée, pour amorcer l'arc électrique et stabiliser son extrémité au potentiel négatif.The generation of an electric arc plasma is a well-known phenomenon, used for several decades in welding torches or recharging known as transferred plasma. Many embodiments have been proposed for these torches. All use the tip effect of a sharp cathode, to strike the electric arc and stabilize its end at negative potential.

La plupart des réalisations existantes sont de structure parfaitement coaxiale. La pointe de la cathode est disposée sur l'axe principal (axe longitudinal) de la torche, et positionnée légèrement en arrière du convergent de la tuyère-anode qui l'entoure coaxialement. Le plasma se propage et sort donc, en principe, suivant l'axe principal de la torche.Most of the existing constructions have a perfectly coaxial structure. The tip of the cathode is arranged on the main axis (longitudinal axis) of the torch, and positioned slightly behind the convergent nozzle-anode which surrounds it coaxially. The plasma propagates and therefore leaves, in principle, along the main axis of the torch.

On connaît aussi des réalisations de torches à plasma d'arc transféré, dans lesquelles le plasma sort de la torche selon une direction formant un angle notable par rapport à l'axe principal de la torche, et peut ainsi être dirigé vers un substrat à travailler selon une direction différente de l'axe principal de la torche.There are also known embodiments of transferred arc plasma torches, in which the plasma leaves the torch in a direction forming a significant angle relative to the main axis of the torch, and can thus be directed towards a substrate to be worked. in a direction different from the main axis of the torch.

Dans toutes les réalisations de ce genre, connues à ce jour, la structure géométrique du dispositif générateur de plasma reste une structure parallèle au plasma, du moins au voisinage de l'origine de celui-ci. Le plasma naît et commence à se propager dans l'axe de l'électrode négative, même si ce plasma est ensuite dévié dudit axe avant le point d'utilisation, notamment par l'orientation oblique d'un conduit de sortie et la position de l'électrode positive constituée par la pièce à recharger sur laquelle l'arc transféré vient se boucler. A titre d'exemples de ce genre de réalisations, on peut notamment citer la torche à plasma transféré selon la demande de brevet français FR-A-2672459 au nom du Demandeur (voir plus particulièrement la figure 3), ou encore le brevet FR-A-1338390.In all such embodiments, known to date, the geometric structure of the plasma generator device remains a structure parallel to the plasma, at least in the vicinity of the origin of the latter. The plasma is born and begins to propagate in the axis of the negative electrode, even if this plasma is then deviated from said axis before the point of use, in particular by the oblique orientation of an outlet conduit and the position of the positive electrode constituted by the part to be recharged on which the transferred arc comes to loop. As examples of this kind of achievements, we can in particular quote the plasma torch transferred according to French patent application FR-A-2672459 in the name of the Applicant (see more particularly FIG. 3), or even patent FR-A-1338390.

Ce genre de réalisations, où la déviation de l'arc est obtenue uniquement par l'orientation du conduit et de l'orifice de sortie du plasma (d'éventuels canaux débouchant dans ce conduit, comme le montre le document précité FR-A-1338390, ne servant qu'à l'apport de poudre), ne donne pas entièrement satisfaction du point de vue de la rigidité de l'arc et du contrôle des paramètres de fonctionnement du plasma.This kind of embodiment, where the deflection of the arc is obtained only by the orientation of the conduit and the plasma outlet orifice (possible channels opening into this conduit, as shown in the aforementioned document FR-A- 1338390, used only for the supply of powder), is not entirely satisfactory from the point of view of the rigidity of the arc and the control of the operating parameters of the plasma.

La présente invention a donc pour but d'améliorer une torche à plasma transféré du genre concerné.The present invention therefore aims to improve a transferred plasma torch of the type concerned.

A cet effet, elle a essentiellement pour objet une torche à plasma transféré comprenant une tuyère-anode entourant coaxialement une cathode disposée suivant l'axe longitudinal de la torche, et un canal de section annulaire ménagé entre la tuyère-anode et la cathode et apte à être parcouru par un débit de gaz plasmagène, la torche étant agencée pour émettre un jet de plasma selon une direction faisant un angle notable par rapport à l'axe longitudinal de la torche, celle-ci étant caractérisée en ce qu'il est prévu, en plus du circuit de gaz plasmagène d'initialisation cheminant le long de la cathode, un autre circuit distinct du précédent, et apte à être parcouru par un débit de gaz plasmagène directionnel, le circuit de gaz plasmagène directionnel débouchant, suivant une direction faisant un angle notable avec l'axe longitudinal de la torche, dans une chambre ou un conduit prolongeant le canal de section annulaire à l'avant de la torche et débouchant lui-même à l'extérieur par un orifice de sortie latéral de la tuyère-anode, de sorte que le plasma est créé et se propage dans une direction faisant un angle notable avec l'axe longitudinal de la torche, suivant lequel est disposée la cathode.For this purpose, it essentially relates to a transferred plasma torch comprising a nozzle-anode coaxially surrounding a cathode disposed along the longitudinal axis of the torch, and a channel of annular section formed between the nozzle-anode and the cathode and capable to be traversed by a flow of plasma gas, the torch being arranged to emit a plasma jet in a direction making a significant angle relative to the longitudinal axis of the torch, the latter being characterized in that it is provided , in addition to the initialization plasma gas circuit passing along the cathode, another circuit distinct from the previous one, and capable of being traversed by a directional plasma gas flow, the directional plasma gas circuit opening out, in a direction making a significant angle with the longitudinal axis of the torch, in a chamber or a conduit extending the annular section channel at the front of the torch and opening itself even outside by a lateral outlet orifice of the nozzle-anode, so that the plasma is created and propagates in a direction making a notable angle with the longitudinal axis of the torch, along which the cathode is arranged.

Ainsi, on utilise dans la torche objet de l'invention deux circuits distincts de gaz plasmagène, l'un d'initialisation cheminant le long de la cathode, et l'autre directionnel arrivant à l'avant de la torche selon une direction formant un angle notable, qui dans un cas typique atteint 90°, par rapport à l'axe principal de la torche (axe du couple anode-cathode). Un phénomène fluidique de déviation d'un jet de gaz à faible vitesse par un jet de débit moindre mais à vitesse élevée intervient alors, pour créer une veine de plasma qui dès l'origine se propage dans une direction qui n'est pas parallèle à l'axe du couple anode-cathode, mais forme un angle notable avec cet axe et est, en particulier, perpendiculaire audit axe. Le recours à un gaz plasmagène déviateur rigidifie l'arc et donne de bien meilleurs résultats que dans les précédentes réalisations, qui ne font pas appel à un gaz plasmagène déviateur et dans lesquelles le plasma est émis suivant l'axe de la cathode et dévié ensuite (comme expliqué plus haut).Thus, in the torch which is the subject of the invention, two separate circuits of plasma-generating gas are used, one for initialization traveling along the cathode, and the other directional arriving at the front of the torch in a direction forming a notable angle, which in a typical case reaches 90 °, with respect to the main axis of the torch (axis of the anode-cathode couple). A fluid phenomenon of deflection of a jet of gas at low speed by a jet of lesser flow but at high speed then intervenes, to create a vein of plasma which from the outset propagates in a direction which is not parallel to the axis of the anode-cathode pair, but forms a notable angle with this axis and is, in particular, perpendicular to said axis. The use of a deflecting plasma gas stiffens the arc and gives much better results than in previous embodiments, which do not use a deflecting plasma gas and in which the plasma is emitted along the axis of the cathode and then deflected (as explained above).

Avantageusement, le circuit de gaz plasmagène d'initialisation et le circuit de gaz plasmagène directionnel sont munis, chacun, de leurs propres moyens de contrôle du débit de gaz, de sorte que le contrôle des paramètres de fonctionnement du plasma résulte directement des réglages absolus et relatifs des deux circuits de gaz plasmagène.Advantageously, the initial plasma plasma circuit and the directional plasma gas circuit are each provided with their own gas flow control means, so that the control of the plasma operating parameters results directly from the absolute settings and relative of the two plasma gas circuits.

Selon un autre aspect de l'invention, la tuyère-anode est prévue pour être montée sur une embase d'une torche, comprenant un bloc-support de cathode dans lequel la cathode est tenue de manière à pouvoir être montée, réglée axialement et démontée par la zone arrière de la torche. Cette disposition facilite en particulier le réglage de positionnement axial de la cathode, qui détermine les caractéristiques du plasma obtenu.According to another aspect of the invention, the nozzle-anode is designed to be mounted on a base of a torch, comprising a cathode support block in which the cathode is held so as to be able to be mounted, axially adjusted and dismounted through the rear area of the torch. This arrangement facilitates in particular the axial positioning adjustment of the cathode, which determines the characteristics of the plasma obtained.

Les opérations ici mentionnées s'effectuent donc commodément par l'arrière de l'embase de la torche, sans démontage d'éléments de faibles dimensions et sans contact direct avec le circuit d'eau de refroidissement.The operations here mentioned are therefore carried out conveniently from the rear of the torch base, without dismantling of small components without direct contact with the cooling water circuit.

En outre, la zone rendue disponible par le changement de direction du jet de plasma au voisinage de l'extrémité libre de la tuyère-anode est utilisable pour loger dans cette zone une partie du circuit de refroidissement par circulation d'eau.In addition, the area made available by the change of direction of the plasma jet in the vicinity of the free end of the nozzle-anode is usable for accommodating in this area part of the cooling circuit by circulation of water.

La torche à plasma d'arc transféré, objet de l'invention, est particulièrement adaptée au rechargement de petits alésages, avec un bain de fusion à plat, la partie cylindrique intérieure à revêtir ayant son axe disposé horizontalement. La torche, qui pénètre dans l'alésage lors de l'opération de rechargement, se trouve alors avec son axe principal horizontal, et seul le jet de plasma est émis verticalement dans une direction radiale à la sortie de l'orifice latéral pratiqué vers l'extrémité libre de la tuyère-anode. Bien entendu, les dimensions hors tout de la tuyère-anode doivent être adaptées au diamètre intérieur de l'alésage de la pièce à recharger, ce qui signifie en pratique que la tuyère-anode est longue et de faible diamètre. L'intérêt d'une telle disposition est de permettre aussi l'utilisation d'une cathode de grande dimension longitudinale, que l'on peut venir monter ou démonter commodément par l'embase de la torche, par exemple pour procéder à son affûtage.The transferred arc plasma torch, object of the invention, is particularly suitable for the reloading of small bores, with a flat melting bath, the internal cylindrical part to be coated having its axis disposed horizontally. The torch, which enters the bore during the reloading operation, is then with its horizontal main axis, and only the plasma jet is emitted vertically in a radial direction at the outlet of the lateral orifice practiced towards the free end of the anode nozzle. Of course, the overall dimensions of the nozzle-anode must be adapted to the internal diameter of the bore of the part to be recharged, which in practice means that the nozzle-anode is long and of small diameter. The advantage of such an arrangement is also to allow the use of a cathode of large longitudinal dimension, which can be conveniently mounted or dismounted by the base of the torch, for example to proceed with its sharpening.

L'invention sera de toute façon mieux comprise à l'aide de la description qui suit, en référence au dessin schématique annexé représentant, à titre d'exemple, une forme d'exécution de cette torche à plasma d'arc transféré :

  • Figure 1 est une vue en coupe longitudinale de la partie avant de la torche, plus particulièrement concernée par la présente invention ;
  • Figure 2 est une vue d'ensemble en coupe longitudinale, très schématique, de cette torche.
The invention will in any case be better understood with the aid of the description which follows, with reference to the appended schematic drawing showing, by way of example, an embodiment of this transferred arc plasma torch:
  • Figure 1 is a longitudinal sectional view of the front part of the torch, more particularly concerned with the present invention;
  • Figure 2 is an overall view in longitudinal section, very schematic, of this torch.

La figure 1 montre la partie avant d'une torche de soudage ou plus particulièrement de rechargement à plasma d'arc transféré, comportant une tuyère-anode 1 entourant une cathode 2 disposée suivant l'axe longitudinal 3 de la torche. Un canal de section annulaire 4 est ménagé entre la tuyère-anode 1 et la cathode 2. Le canal 4 est parcouru par un premier débit de gaz plasmagène cheminant le long de la cathode 2, comme indiqué par une flèche 5, ce canal 4 appartenant à un circuit de gaz plasmagène ayant pour rôle l'initialisation de l'ionisation du gaz et protection de la cathode 2. Le gaz plasmagène d'initialisation est réparti à l'entrée du convergent 6 de la tuyère-anode 1 au moyen d'une bague 7 ménageant des passages hélicoïdaux, qui donne au gaz un mouvement tourbillonnaire apte à stabiliser la décharge naissant entre l'extrémité en pointe 8 de la cathode 2 et l'anode 1. La bague 7 joue aussi le rôle de moyen de centrage de la cathode 2 relativement à la tuyère-anode 1.FIG. 1 shows the front part of a welding torch or more particularly of reloading with transferred arc plasma, comprising a nozzle-anode 1 surrounding a cathode 2 arranged along the longitudinal axis 3 of the torch. An annular section channel 4 is formed between the nozzle-anode 1 and the cathode 2. The channel 4 is traversed by a first flow of plasma gas traveling along the cathode 2, as indicated by an arrow 5, this channel 4 belonging to a plasma gas circuit with the role of initializing the ionization of the gas and protecting the cathode 2. The plasma initialization gas is distributed at the inlet of the convergent 6 of the nozzle-anode 1 by means of a ring 7 providing helical passages, which gives the gas a swirling movement capable of stabilizing the incipient discharge between the pointed end 8 of the cathode 2 and the anode 1. The ring 7 also acts as a centering means for cathode 2 relative to the nozzle-anode 1.

A son extrémité avant, le canal 4 est prolongé par un court conduit 9 convergent orienté suivant un axe 10 formant un angle notable A par rapport à l'axe longitudinal 3 de la torche, et débouchant à l'extérieur par un orifice de sortie 11 situé sur la paroi latérale de la tuyère-anode 1. Dans l'exemple considéré, l'angle A est égal à 90°.At its front end, the channel 4 is extended by a short convergent conduit 9 oriented along an axis 10 forming a significant angle A relative to the longitudinal axis 3 of the torch, and opening to the outside by an outlet orifice 11 located on the side wall of the nozzle-anode 1. In the example considered, the angle A is equal to 90 °.

Dans la tuyère-anode 1 est ménagé, parallèlement au canal 4 balayé par le gaz plasmagène d'initialisation, un autre canal 12 qui présente, à sa partie antérieure, un coude à angle droit 13 avec convergent, débouchant à l'arrière du conduit 9, suivant l'axe transversal 10. Le canal 12 est parcouru, comme indiqué par une flèche 14, par un second débit de gaz plasmagène, dit gaz plasmagène directionnel, parcourant ainsi un circuit distinct de celui du gaz plasmagène d'initialisation.In the nozzle-anode 1 is formed, parallel to the channel 4 swept by the initial plasma gas, another channel 12 which has, at its front part, a right angle bend 13 with converging, opening out at the rear of the conduit 9, along the transverse axis 10. The channel 12 is traversed, as indicated by an arrow 14, by a second flow of plasma gas, said directional plasma gas, thus traversing a circuit distinct from that of the initial plasma gas.

Chacun de ces deux circuits indépendants est muni de ses propres moyens (non représentés) de contrôle du débit de gaz plasmagène. D'une façon générale, le jet de plasma émis à l'extrémité antérieure du canal 4 est dévié d'environ 90° par le jet de gaz plasmagène directionnel, de débit moindre mais de vitesse élevée, qui est éjecté par le coude convergent 13 et arrive ainsi dans le conduit 9 en imposant sa propre direction au flux de plasma. Le plasma créé se propage ainsi, dès l'origine, dans la direction de l'axe 10, donc sensiblement perpendiculairement à l'axe 3 de la torche, pour s'échapper par l'orifice de sortie latéral 11.Each of these two independent circuits is provided with its own means (not shown) for controlling the plasma gas flow. In general, the plasma jet emitted at the anterior end of channel 4 is deflected by approximately 90 ° by the jet of directional plasma gas, of lower flow rate but of high speed, which is ejected by the converging elbow 13 and thus arrives in the duct 9 by imposing its own direction on the plasma flow. The plasma created thus propagates, from the outset, in the direction of the axis 10, therefore substantially perpendicular to the axis 3 of the torch, to escape through the lateral outlet orifice 11.

L'espace rendu libre par le changement de direction du jet de plasma, au voisinage de l'extrémité de la tuyère-anode, est mis à profit pour faire passer à cet endroit le circuit d'eau de refroidissement 15 de la torche, assurant ainsi dans cette zone un refroidissement énergique.The space made free by the change of direction of the plasma jet, in the vicinity of the end of the nozzle-anode, is used to pass the cooling water circuit 15 of the torch there, ensuring thus in this zone an energetic cooling.

La figure 2 représente dans son ensemble la torche équipée du dispositif générateur de plasma précédemment décrit, dans une réalisation particulière s'inspirant de la demande de brevet français FR-A-2672459 au nom du Demandeur.FIG. 2 shows as a whole the torch equipped with the plasma generator device described above, in a particular embodiment inspired by French patent application FR-A-2672459 in the name of the Applicant.

En particulier, la partie droite de la figure 2 montre l'embase 16 de la torche, qui comprend un bloc-support de cathode 17 séparé par un isolateur 18 d'une embase d'anode 19. Ces trois composants 17, 18 et 19, qui constituent l'embase 16 de la torche, sont dotés de tous les canaux nécessaires à l'acheminement des fluides permettant le fonctionnement de la torche :

  • Le circuit d'eau de refroidissement 15 est collecté en 20 sur l'embase d'anode 19, puis il parcourt la tuyère-anode 1 jusqu'à son extrémité avant, avant de revenir à travers l'embase d'anode 19 ainsi que l'isolateur 18 jusqu'au bloc-support 17 de la cathode 2, où il est évacué en 21, ce circuit d'eau n'étant représenté que partiellement du fait qu'il s'étend dans un plan autre que le plan de coupe des figures 1 et 2.
  • Un canal d'alimentation 22, ménagé dans le bloc-support 17 de la cathode 2, débouche à l'arrière du canal 4 de section annulaire et sert à l'amenée du gaz plasmagène d'initialisation.
  • Un canal 23, traversant successivement les composants 17,18 et 19 de l'embase 16 de la torche, et se prolongeant dans la tuyère-anode 1 jusqu'à un débouché latéral 24 proche de l'orifice 11, assure l'amenée du mélange gaz-poudre d'apport d'alliage métallique constitutif du dépôt.
  • Un autre canal 25, traversant successivement les composants 17,18 et 19 de l'embase 16 de la torche, se prolonge dans la tuyère-anode 1 par le canal 12 précité, et sert à l'acheminement du gaz plasmagène directionnel.
  • Il est encore prévu un canal d'alimentation du gaz protecteur (non représenté), qui est dirigé vers un diffuseur approprié.
In particular, the right part of FIG. 2 shows the base 16 of the torch, which comprises a cathode support block 17 separated by an insulator 18 from an anode base 19. These three components 17, 18 and 19 , which constitute the base 16 of the torch, are provided with all the channels necessary for the routing of the fluids allowing the operation of the torch:
  • The cooling water circuit 15 is collected at 20 on the anode base 19, then it traverses the nozzle-anode 1 to its front end, before returning through the anode base 19 as well as the insulator 18 to the support block 17 of the cathode 2, where it is discharged at 21, this water circuit being only shown partially because it extends in a plane other than the plane of section of Figures 1 and 2.
  • A supply channel 22, formed in the support block 17 of the cathode 2, opens at the rear of the channel 4 of annular section and is used for supplying the initial plasma gas.
  • A channel 23, successively passing through the components 17, 18 and 19 of the base 16 of the torch, and extending into the nozzle-anode 1 as far as a lateral outlet 24 close to the orifice 11, ensures the supply of the gas-powder mixture of metallic alloy supply constituting the deposit.
  • Another channel 25, successively passing through the components 17, 18 and 19 of the base 16 of the torch, is extended in the nozzle-anode 1 by the aforementioned channel 12, and is used for conveying the directional plasma gas.
  • A protective gas supply channel (not shown) is also provided, which is directed towards a suitable diffuser.

A l'arrière de l'embase de la torche, la cathode 2 est tenue sur son bloc-support 17 au moyen d'une pince 26. Un écrou borgne (non représenté), vissé sur un filetage 27 du bloc-support 17, donne un accès très direct à la cathode 2 que l'on peut ainsi immobiliser dans la position axiale souhaitée.At the rear of the base of the torch, the cathode 2 is held on its support block 17 by means of pliers 26. A blind nut (not shown), screwed onto a thread 27 of the support block 17, gives very direct access to the cathode 2 which can thus be immobilized in the desired axial position.

Cette position axiale de la cathode 2, ainsi que les réglages indépendants des débits du gaz plasmagène d'initialisation 5 et du gaz plasmagène directionnel 14, constituent les trois principaux éléments de réglage de la torche.This axial position of the cathode 2, as well as the independent adjustments of the flow rates of the initial plasma gas 5 and the directional plasma gas 14, constitute the three main elements for adjusting the torch.

Bien entendu, en fonction de chaque cas d'application et comme cela est habituel dans les procédés de rechargement par torche à plasma d'arc transféré, les autres paramètres de fonctionnement, tels que par exemple l'intensité transférée, seront à ajuster en fonction des épaisseurs, taux de dépôts et autres données particulières rencontrées.Of course, as a function of each application case and as is usual in recharging processes by plasma torch of transferred arc, the other operating parameters, such as for example the intensity transferred, will have to be adjusted as a function thicknesses, deposit rates and other specific data encountered.

Il va de soi que l'invention ne se limite pas à la seule forme d'exécution de cette torche à plasma d'arc transféré qui a été décrite ci-dessus, à titre d'exemple ; elle en embrasse, au contraire, toutes les variantes de réalisation et d'application entrant dans le cadre des revendications annexées. En particulier, l'on ne s'éloignerait pas de l'esprit de l'invention en modifiant l'angle A de la direction de propagation du plasma par rapport à l'axe longitudinal 3 de la torche, la valeur particulière de 90° de cet angle donnée par l'exemple illustré au dessin n'étant nullement limitative. Dans le même ordre d'idées, on peut substituer à l'embase de torche particulière, donnée ici en exemple, une structure différente des organes servant de supports pour l'anode et la cathode, ainsi que de collecteurs et distributeurs pour les divers fluides spécifiques au fonctionnement ou au refroidissement du genre de torche concerné. Enfin, les formes de détail de la torche peuvent être modifiées, par exemple l'orifice de sortie latéral peut être situé en retrait, par rapport au restant de la paroi latérale cylindrique de la tuyère-anode 1.It goes without saying that the invention is not limited to the only embodiment of this transferred arc plasma torch which has been described above, by way of example; on the contrary, it embraces all the variant embodiments and applications coming within the scope of the appended claims. In particular, one would not depart from the spirit of the invention by modifying the angle A of the direction of propagation of the plasma relative to the longitudinal axis 3 of the torch, the particular value of 90 °. of this angle given by the example illustrated in the drawing being in no way limiting. In the same vein, we can substitute for the particular torch base, given here as an example, a different structure from the organs serving as supports for the anode and the cathode, as well as from collectors and distributors for the various fluids. specific to the operation or cooling of the type of torch concerned. Finally, the forms of detail of the torch can be modified, for example the lateral outlet orifice can be set back, relative to the remainder of the cylindrical side wall of the nozzle-anode 1.

Claims (5)

  1. Torch for welding or more particularly for transferred arc plasma build-up welding, comprising a nozzle/anode (1) coaxially surrounding a cathode (2), disposed along the longitudinal axis (3) of the torch, and a duct (4) with an annular cross section formed between the nozzle/anode (1) and the cathode (2) and suitable for having a flow of plasmagenic gas (5) pass through it, the torch being arranged so as to emit a jet of plasma in a direction (10) forming a significant angle (A) with respect to the longitudinal axis (3) of the torch, characterised in that there is provided, in addition to the initiating plasmagenic gas circuit (4, 22) running along the cathode (1), another circuit (12, 13, 25) distinct from the previous one, and suitable for having pass through it a directional flow of plasmagenic gas (14), the directional plasmagenic gas circuit opening out (at 13), along a direction (10) forming a significant angle (A) with the longitudinal axis (3) of the torch, into a chamber or a pipe (9) extending the duct (4) with an annular cross section, to the front of the torch and itself opening out on the outside through a lateral outlet orifice (11) of the nozzle/anode (1), so that the plasma is created and propagated in a direction which forms a significant angle with the longitudinal axis (3) of the torch, along which the cathode (2) is disposed.
  2. Transferred arc plasma torch according to Claim 1, characterised in that the directional plasmagenic gas circuit (12, 13, 25) has, in its front part, a right-angled elbow (13), with a convergent part, opening out at the rear of the aforementioned chamber or pipe (9), so as to divert the plasma jet, in a direction (10) forming an angle of around 90° with respect to the longitudinal axis (3) of the torch, along which the cathode is disposed (2).
  3. Transferred arc plasma torch according to Claim 1 or 2, characterised in that the initiating plasmagenic gas circuit (4, 22) and the directional plasmagenic gas circuit (12, 13, 25) are each provided with their own gas flow control means, so that the control of the operating parameters of the plasma depends directly on the absolute and relative settings of the two plasmagenic gas circuits.
  4. Transferred arc plasma torch according to any one of Claims 1 to 3, characterised in that the nozzle/anode (1) is designed to be mounted on the holder (16) of a torch, comprising a cathode support block (17) in which the cathode (2) is held (at 26) so as to be able to be fitted, axially adjusted and removed from the rear part of the torch.
  5. Transferred arc plasma torch according to any one of Claims 1 to 4, characterised in that part of a water-circulation cooling circuit (15) is housed in the area of the free end of the nozzle/anode (1), this area being made available by changing the direction of the plasma jet.
EP94420206A 1993-07-15 1994-07-13 Transferred arc plasma torch Expired - Lifetime EP0634887B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9308802A FR2707824B1 (en) 1993-07-15 1993-07-15 Transferred plasma torch (PTA) with radial cathode.
FR9308802 1993-07-15

Publications (2)

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EP0634887A1 EP0634887A1 (en) 1995-01-18
EP0634887B1 true EP0634887B1 (en) 1996-10-16

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EP94420206A Expired - Lifetime EP0634887B1 (en) 1993-07-15 1994-07-13 Transferred arc plasma torch

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EP (1) EP0634887B1 (en)
AT (1) ATE144368T1 (en)
DE (1) DE69400737D1 (en)
FR (1) FR2707824B1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5837959A (en) * 1995-09-28 1998-11-17 Sulzer Metco (Us) Inc. Single cathode plasma gun with powder feed along central axis of exit barrel
AT4599U1 (en) * 2000-06-21 2001-09-25 Inocon Technologie Gmbh PLASMA TORCH
DE102006012100B3 (en) * 2006-03-16 2007-09-20 Maschinenfabrik Reinhausen Gmbh Apparatus for generating a plasma jet
US9211603B2 (en) 2012-01-31 2015-12-15 The Esab Group, Inc. Plasma gouging torch and angled nozzle therefor
US9781818B2 (en) 2012-08-06 2017-10-03 Hypertherm, Inc. Asymmetric consumables for a plasma arc torch
US9107282B2 (en) 2012-08-06 2015-08-11 Hypertherm, Inc. Asymmetric consumables for a plasma arc torch
US9497845B2 (en) 2012-08-06 2016-11-15 Hypertherm, Inc. Consumables for a plasma arc torch for bevel cutting
US10314155B2 (en) 2012-08-06 2019-06-04 Hypertherm, Inc. Asymmetric consumables for a plasma arc torch
US10721812B2 (en) 2012-08-06 2020-07-21 Hypertherm, Inc. Asymmetric consumables for a plasma arc torch
CN115734449B (en) * 2022-11-29 2023-11-14 哈尔滨工程大学 Plasma arc generator for fixing arc generation position

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1338390A (en) * 1962-07-05 1963-09-27 Air Liquide Adjustable plasma generator head
US3575568A (en) * 1967-06-08 1971-04-20 Rikagaku Kenkyusho Arc torch
US3740522A (en) * 1971-04-12 1973-06-19 Geotel Inc Plasma torch, and electrode means therefor
FR2672459B1 (en) * 1991-02-01 1993-04-30 Girard Frederic PLASMA RECHARGING DEVICE WITH OBLIQUE ORIFICE.

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Publication number Publication date
FR2707824B1 (en) 1995-12-01
DE69400737D1 (en) 1996-11-21
ATE144368T1 (en) 1996-11-15
EP0634887A1 (en) 1995-01-18
FR2707824A1 (en) 1995-01-20

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