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EP0427590B1 - Plasma torch with electromagnetic coil for rotating the arc - Google Patents

Plasma torch with electromagnetic coil for rotating the arc Download PDF

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Publication number
EP0427590B1
EP0427590B1 EP90403044A EP90403044A EP0427590B1 EP 0427590 B1 EP0427590 B1 EP 0427590B1 EP 90403044 A EP90403044 A EP 90403044A EP 90403044 A EP90403044 A EP 90403044A EP 0427590 B1 EP0427590 B1 EP 0427590B1
Authority
EP
European Patent Office
Prior art keywords
electrodes
electromagnetic coil
plasma torch
electrode
torch according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP90403044A
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German (de)
French (fr)
Other versions
EP0427590A1 (en
Inventor
Maxime Labrot
Jean Feuillerat
Serge Georges Roger Muller
Patrick Lautissier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Airbus Group SAS
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Airbus Group SAS
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Publication of EP0427590A1 publication Critical patent/EP0427590A1/en
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Classifications

    • 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
    • H05H1/28—Cooling arrangements
    • 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
    • H05H1/40—Details, e.g. electrodes, nozzles using applied magnetic fields, e.g. for focusing or rotating the arc
    • 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
    • H05H1/3431—Coaxial cylindrical electrodes

Definitions

  • the present invention relates to plasma torches in which the plasma is obtained by heating a gas by an electric arc produced between two electrodes.
  • a plasma torch as taught for example the document US-A-3 301 995, comprises two tubular and coaxial electrodes, each being arranged in a support which surrounds it.
  • the plasma torch also comprises means for producing the initiation of an electric arc between the two electrodes and means for injecting a plasma gas, such as air, between the two electrodes, simultaneously with the electric arc.
  • Means for cooling the electrodes are also provided in each electrode support and are usually defined by a sealed cylindrical chamber provided in each support, a cylindrical separation wall providing the sealed chamber in two concentric annular spaces, in communication with one the other at one end of said wall and through which a cooling fluid circulates.
  • means are provided for moving the attachment feet of the arc on the internal surfaces of the tubular electrodes.
  • these means are defined by at least one electromagnetic coil surrounding one of the electrode supports.
  • one solution consists in arranging them in an internal volume provided in each electrode support, as taught in document US-A-3,832,519.
  • the gain in size n is not significant, the support being of larger dimension, and moreover, the coils are provided with complex internal cooling circuits.
  • the present invention aims to remedy these drawbacks and relates to an electric arc plasma torch, the arrangement of the means for moving the electric arc does not lead to an increase in volume of said torch, nor to complications. additional techniques.
  • the space previously imposed by the electromagnetic coil is completely eliminated since the latter is then integrated into said electrode holder support by replacing the cylindrical wall for separating the cooling means, initially provided in the support.
  • said coil is then effectively cooled by the fluid passing through the two concentric annular spaces between which the electromagnetic coil is arranged.
  • said electromagnetic coil extends approximately over the entire length of the electrode; preferably, it is associated with the support surrounding the upstream electrode (relative to the circulation of the plasma gas).
  • said electromagnetic coil is defined by two concentric windings of contiguous turns, an envelope of insulating material being interposed between the two concentric windings of turns.
  • This envelope of insulating material thus constitutes a sealed separation wall allowing the coolant to pass through the two annular spaces.
  • the two windings of turns can be obtained from a continuous metal wire.
  • This wire preferably has a rectangular section, so that each of said windings with contiguous turns then has a united surface.
  • said electromagnetic coil is connected by one of its ends to a power supply line and by the other end to a ring integral with said corresponding support.
  • the power supply line advantageously travels through the electrically insulating coolant supply pipe.
  • FIG. 1 schematically represents a half-view in longitudinal section contiguous to an external half-view of a particular embodiment of the plasma torch according to the invention.
  • Figure 2 is an enlarged half-section view of the electromagnetic coil disposed in the support of the upstream electrode.
  • the plasma torch 1 comprises a body 2 comprising in particular two cylindrical supports 3 and 4.
  • An upstream electrode or cathode 5 is housed inside the support 3, and, in an identical manner, an electrode downstream or anode 6 is housed inside the support 4.
  • These electrodes 5 and 6, of generally tubular shape, have a common axis 7, being spaced apart from each other along said axis, and they are connected to a power supply by circuits not shown but of known type.
  • the plasma torch 1 also comprises means 8.1 and 8.2 for cooling the electrodes, which are provided, in the usual way, in each of the supports 3 and 4, and which will be described later.
  • FIG. 1 shows the electric arc 10 thus generated, whose attachment feet 10.1 and 10.2 are located on the internal surfaces, respectively 5A and 6A, of the electrodes 5 and 6.
  • a plasma gas such as air
  • the gas coming from a circuit supply known per se and not shown, passes through a passage 12 formed in the body 1 then, transverse injection orifices 13 provided in a cylindrical part 14 surrounding the opposite ends of the electrodes, to then open into the chamber 11, the thermal plasma exiting through the downstream tubular electrode 6.
  • the plasma torch 1 comprises means for moving the attachment feet of the electric arc generated around the internal surfaces of the tubular electrodes 5 and 6. These means are defined by at least an electromagnetic coil 15 associated, in this embodiment, with the support 3 of the upstream electrode 5.
  • the electromagnetic coil 15 is integrated into the cooling circuit 8.1 of the electrode 5.
  • the cooling circuit 8.1 is defined by a sealed cylindrical chamber 16 provided between the support 3 and the external surface 58 of the electrode 5, being separated, by the electromagnetic coil 15, into two concentric annular spaces 16A and 16B through which the coolant circulates, said annular spaces being in communication with one the other at the downstream end 15A of said coil 15.
  • the electromagnetic coil 15 thus acts as a partition wall for the annular spaces 16A and 16B, so that this arrangement does not involve any additional bulk of the plasma torch.
  • the cooling fluid is electrically insulating such as, for example, deionized water.
  • This fluid coming from a supply circuit known per se and not shown, arrives via a conduit 27 opening into the sealed chamber 16 to circulate in the annular space 16A, between the support 3 and the coil 15, then in the annular space 16B, between the coil 15 and the external surface 58 of the electrode, to emerge through a passage 5C provided in the rear end 5D of the electrode 5 in the direction of said circuit.
  • the circulation of the fluid is indicated by arrows F. It can therefore be seen that the electromagnetic coil 15, which extends around the electrode 5, is cooled optimally by the cooling fluid.
  • the electromagnetic coil 15 is defined by two concentric windings 17A and 17B of contiguous turns, obtained from a continuous metallic wire 17, for example made of copper. Between the two windings of turns 17A and 17B is placed an envelope of insulating material 18 which thus constitutes a sealed wall separating the two annular spaces 16A and 16B. Furthermore, it can be seen that the wire of the turns forming the windings of the coil 15 advantageously has a solid rectangular section.
  • the coil 15 is fixed by one of its ends 20 to a metal ring 21 conforming to a part of the cooling circuit and interposed between the support 5 and the rear end 5D of the electrode 5, while the other end 22 of the coil, isolated from the metallic mass, is connected to an electrical supply line 23.
  • this supply line 23 travels inside the duct 27 for supplying cooling fluid, so that it is thus effectively cooled.
  • the cooling circuit 8.2 of the downstream electrode 6 is supplied with cooling fluid by a conduit 24.
  • the various supplies of plasma gas and of cooling fluid, as well as the electrical supplies of the electrodes and of the coil, are of known type. and are connected to a control system ensuring the proper functioning of the plasma torch according to the methods assigned to it.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Plasma Technology (AREA)
  • Arc Welding Control (AREA)
  • Circuit Breakers (AREA)
  • Arc-Extinguishing Devices That Are Switches (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)

Abstract

The invention relates to a plasma torch of the type comprising - two tubular and coaxial electrodes (5 and 6), one a continuation of the other, each electrode being arranged in a holder (3 and 4); - fluid-flushed means of cooling said electrodes, the said means of at least one electrode comprising a sealed cylindrical chamber (16) provided in the corresponding holder and separated by a cylindrical wall dividing the chamber into two communicating annular spaces (16A and 16B) through which the said coolant fluid circulates; - means (9) for initiating an electric arc between the electrodes; - means (11, 13) for injecting a plasma-forming gas between the electrodes; and, - electromagnetic coil means for displacing the pick-up points of the said electric arc onto the inner surfaces of the said electrodes. According to the invention, the coolant fluid for the said electrode, whose sealed chamber (16) contains the separation wall, is electrically insulating and the said electromagnetic coil (15) does the job of the separation wall.

Description

La présente invention concerne les torches à plasma dans lesquelles le plasma est obtenu en chauffant un gaz par un arc électrique produit entre deux électrodes.The present invention relates to plasma torches in which the plasma is obtained by heating a gas by an electric arc produced between two electrodes.

On connaît déjà de nombreuses réalisations de torches à plasma. Généralement, une torche à plasma, telle que l'enseigne par exemple le document US-A-3 301 995, comprend deux électrodes tubulaires et coaxiales, chacune étant agencée dans un support qui l'entoure. La torche à plasma comporte également des moyens pour produire l'amorçage d'un arc électrique entre les deux électrodes et des moyens pour injecter un gaz plasmagène, tel que de l'air, entre les deux électrodes, simultanément à l'arc électrique. Des moyens de refroidissement des électrodes sont également prévus dans chaque support d'électrode et sont usuellement définis par une chambre cylindrique étanche prévue dans chaque support, une paroi cylindrique de séparation ménageant la chambre étanche en deux espaces annulaires concentriques, en communication l'un avec l'autre à une extrémité de ladite paroi et à travers lesquels circule un fluide de refroidissement.Numerous embodiments of plasma torches are already known. Generally, a plasma torch, as taught for example the document US-A-3 301 995, comprises two tubular and coaxial electrodes, each being arranged in a support which surrounds it. The plasma torch also comprises means for producing the initiation of an electric arc between the two electrodes and means for injecting a plasma gas, such as air, between the two electrodes, simultaneously with the electric arc. Means for cooling the electrodes are also provided in each electrode support and are usually defined by a sealed cylindrical chamber provided in each support, a cylindrical separation wall providing the sealed chamber in two concentric annular spaces, in communication with one the other at one end of said wall and through which a cooling fluid circulates.

Par ailleurs, comme l'enseignent par exemple les documents US-A-3 301 995 et EP-A-0 032 100, pour éviter une usure prématurée des électrodes, on prévoit des moyens pour déplacer les pieds d'accrochage de l'arc électrique sur les surfaces internes des électrodes tubulaires. Généralement, ces moyens sont définis par au moins une bobine électromagnétique entourant l'un des supports d'électrode. Ainsi, en modulant le champ magnétique axial engendré par la bobine lorsqu'elle est excitée, les pieds d'accrochage de l'arc électrique se déplacent autour des surfaces internes des électrodes en évitant la formation de cratères locaux et la destruction rapide des électrodes.Furthermore, as taught for example documents US-A-3 301 995 and EP-A-0 032 100, to prevent premature wear of the electrodes, means are provided for moving the attachment feet of the arc on the internal surfaces of the tubular electrodes. Generally, these means are defined by at least one electromagnetic coil surrounding one of the electrode supports. Thus, by modulating the axial magnetic field generated by the coil when it is excited, the attachment feet of the electric arc move around the internal surfaces of the electrodes, avoiding the formation of local craters and rapid destruction of the electrodes.

Toutefois, l'agencement d'une telle bobine électromagnétique autour du support porte-électrode implique une augmentation importante de l'encombrement de la torche à plasma, de sorte que, dans certaines applications, les torches à plasma ainsi équipées ne satisfont pas aux exigences de volume et de forme requises.However, the arrangement of such an electromagnetic coil around the electrode-holder support implies a significant increase in the size of the plasma torch, so that, in certain applications, the plasma torches thus equipped do not meet the requirements volume and shape required.

Pour diminuer l'encombrement extérieur imposé par les bobines, une solution consiste à les agencer dans un volume interne prévu dans chaque support d'électrode, comme l'enseigne le document US-A-3 832 519. Néanmoins, le gain en encombrement n'est pas significatif, le support étant de dimension plus importante, et de plus, les bobines sont munies de circuits de refroidissement internes complexes.To reduce the external dimensions imposed by the coils, one solution consists in arranging them in an internal volume provided in each electrode support, as taught in document US-A-3,832,519. However, the gain in size n is not significant, the support being of larger dimension, and moreover, the coils are provided with complex internal cooling circuits.

La présente invention a pour but de remédier à ces inconvénients et concerne une torche à plasma d'arc électrique, dont l'agencement des moyens de déplacement de l'arc électrique n'entraîne pas une augmentation de volume de ladite torche, ni de complications techniques supplémentaires.The present invention aims to remedy these drawbacks and relates to an electric arc plasma torch, the arrangement of the means for moving the electric arc does not lead to an increase in volume of said torch, nor to complications. additional techniques.

A cet effet, la torche à plasma du type comportant :

  • deux électrodes tubulaires et coaxiales, en prolongement l'une de l'autre, chaque électrode étant agencée dans un support ;
  • des moyens de refroidissement desdites électrodes parcourus par un fluide de refroidissement, lesdits moyens de refroidissement d'au moins une desdites électrodes comprenant une chambre cylindrique étanches, prévue dans le support correspondant et séparée par une paroi cylindrique de séparation partageant la chambre en deux espaces annulaires, en communication l'un avec l'autre à une extrémité de ladite paroi et à travers lesquels circule ledit fluide de refroidissement ;
  • des moyens pour produire l'amorçage d'un arc électrique entre les deux électrodes ;
  • des moyens pour injecter un gaz plasmagène entre les deux électrodes ; et,
  • des moyens à bobine électromagnétique pour déplacer les pieds d'accrochage de l'arc électrique sur les surfaces internes desdites électrodes,

est remarquable, selon l'invention, en ce que le fluide de refroidissement de ladite électrode dont la chambre cylindrique étanche comporte la paroi de séparation est électriquement isolant et en ce que ladite bobine électromagnétique fait office de ladite paroi cylindrique de séparation.For this purpose, the plasma torch of the type comprising:
  • two tubular and coaxial electrodes, in extension of one another, each electrode being arranged in a support;
  • means for cooling said electrodes traversed by a cooling fluid, said means for cooling at least one of said electrodes comprising a sealed cylindrical chamber, provided in the corresponding support and separated by a cylindrical partition wall dividing the chamber into two annular spaces , in communication with each other at one end of said wall and through which circulates said cooling fluid;
  • means for generating an electric arc between the two electrodes;
  • means for injecting a plasma gas between the two electrodes; and,
  • electromagnetic coil means for moving the hooking feet of the electric arc on the internal surfaces of said electrodes,

is remarkable, according to the invention, in that the coolant of said electrode whose sealed cylindrical chamber comprises the partition wall is electrically insulating and in that said electromagnetic coil acts as said cylindrical partition wall.

Ainsi, grâce à l'invention, l'encombrement imposé préalablement par la bobine électromagnétique est totalement supprimé puisque celle-ci est alors intégrée audit support porte-électrode en se substituant à la paroi cylindrique de séparation des moyens de refroidissement, prévue initialement dans le support.Thus, thanks to the invention, the space previously imposed by the electromagnetic coil is completely eliminated since the latter is then integrated into said electrode holder support by replacing the cylindrical wall for separating the cooling means, initially provided in the support.

Par ailleurs, on remarquera que ladite bobine est alors refroidie efficacement par le fluide parcourant les deux espaces annulaires concentriques entre lesquels est agencée la bobine électromagnétique.Furthermore, it will be noted that said coil is then effectively cooled by the fluid passing through the two concentric annular spaces between which the electromagnetic coil is arranged.

Avantageusement, ladite bobine électromagnétique s'étend approximativement sur toute la longueur de l'électrode ; de préférence, elle est associée au support entourant l'électrode amont (par rapport à la circulation du gaz plasmagène).Advantageously, said electromagnetic coil extends approximately over the entire length of the electrode; preferably, it is associated with the support surrounding the upstream electrode (relative to the circulation of the plasma gas).

Dans un mode préféré de réalisation, ladite bobine électromagnétique est définie par deux enroulements concentriques de spires jointives, une enveloppe de matière isolante étant intercalée entre les deux enroulements concentriques de spires. Cette enveloppe de matière isolante constitue ainsi une paroi de séparation étanche permettant au fluide de refroidissement de parcourir les deux espaces annulaires.In a preferred embodiment, said electromagnetic coil is defined by two concentric windings of contiguous turns, an envelope of insulating material being interposed between the two concentric windings of turns. This envelope of insulating material thus constitutes a sealed separation wall allowing the coolant to pass through the two annular spaces.

Selon une autre caractéristique, les deux enroulements de spires peuvent être obtenus à partir d'un fil métallique continu. Ce fil présente, de préférence, une section rectangulaire, de sorte que chacun desdits enroulements à spires jointives présente alors une surface unie.According to another characteristic, the two windings of turns can be obtained from a continuous metal wire. This wire preferably has a rectangular section, so that each of said windings with contiguous turns then has a united surface.

Par ailleurs, ladite bobine électromagnétique est raccordée par l'une de ses extrémités à une ligne d'alimentation électrique et par l'autre extrémité à une bague solidaire dudit support correspondant. La ligne d'alimentation électrique chemine avantageusement à travers le conduit d'amenée de fluide de refroidissement électriquement isolant.Furthermore, said electromagnetic coil is connected by one of its ends to a power supply line and by the other end to a ring integral with said corresponding support. The power supply line advantageously travels through the electrically insulating coolant supply pipe.

Les figures du dessin annexé feront bien comprendre comment l'invention peut être réalisée. Sur ces figures, des références identiques désignent des éléments semblables.The figures of the appended drawing will make it clear how the invention can be implemented. In these figures, identical references designate similar elements.

La figure 1 représente schématiquement une demi-vue en coupe longitudinale contiguë à une demi-vue extérieure d'un mode particulier de réalisation de la torche à plasma selon l'invention.FIG. 1 schematically represents a half-view in longitudinal section contiguous to an external half-view of a particular embodiment of the plasma torch according to the invention.

La figure 2 est une demi-vue en coupe agrandie de la bobine électromagnétique disposée dans le support de l'électrode amont.Figure 2 is an enlarged half-section view of the electromagnetic coil disposed in the support of the upstream electrode.

En se référant à la figure 1, la torche à plasma 1 comporte un corps 2 comprenant notamment deux supports cylindriques 3 et 4. Une électrode amont ou cathode 5 est logée à l'intérieur du support 3, et, de façon identique, une électrode aval ou anode 6 est logée à l'intérieur du support 4. Ces électrodes 5 et 6, de forme générale tubulaire, présentent un axe commun 7, en étant espacées l'une de l'autre le long dudit axe, et elles sont reliées à une alimentation électrique par des circuits non représentés mais de type connu.Referring to FIG. 1, the plasma torch 1 comprises a body 2 comprising in particular two cylindrical supports 3 and 4. An upstream electrode or cathode 5 is housed inside the support 3, and, in an identical manner, an electrode downstream or anode 6 is housed inside the support 4. These electrodes 5 and 6, of generally tubular shape, have a common axis 7, being spaced apart from each other along said axis, and they are connected to a power supply by circuits not shown but of known type.

La torche à plasma 1 comprend également des moyens de refroidissement 8.1 et 8.2 des électrodes, qui sont prévus, de façon usuelle, dans chacun des supports 3 et 4, et qui seront décrits ultérieurement.The plasma torch 1 also comprises means 8.1 and 8.2 for cooling the electrodes, which are provided, in the usual way, in each of the supports 3 and 4, and which will be described later.

Par ailleurs, pour amorcer un arc électrique entre les deux électrodes 5 et 6, on prévoit, par exemple, une électrode auxiliaire de démarrage 9 qui est montée, de façon coulissante, sur le support 4 en étant liée électriquement à l'électrode aval 6. Dans ce cas, on réalise l'amorçage de l'arc électrique par court-circuit en mettant en contact l'électrode auxiliaire 9 avec l'électrode amont 5. On a représenté sur la figure 1 l'arc électrique 10 ainsi engendré, dont les pieds d'accrochage 10.1 et 10.2 sont situés sur les surfaces internes, respectivement 5A et 6A, des électrodes 5 et 6.Furthermore, to initiate an electric arc between the two electrodes 5 and 6, provision is made, for example, for an auxiliary starting electrode 9 which is slidably mounted on the support 4 while being electrically connected to the downstream electrode 6 In this case, the electric arc is started by short circuit by bringing the auxiliary electrode 9 into contact with the upstream electrode 5. FIG. 1 shows the electric arc 10 thus generated, whose attachment feet 10.1 and 10.2 are located on the internal surfaces, respectively 5A and 6A, of the electrodes 5 and 6.

Dès l'apparition de l'arc électrique 10, un gaz plasmagène, tel que de l'air, est injecté dans une chambre d'injection 11, entre les électrodes 5 et 6. Pour cela, le gaz, issu d'un circuit d'alimentation connu en soi et non représenté, traverse un passage 12 ménagé dans le corps 1 puis, des orifices transversaux d'injection 13 prévus dans une pièce cylindrique 14 entourant les extrémités en regard des électrodes, pour déboucher ensuite dans la chambre 11, le plasma thermique sortant par l'électrode tubulaire aval 6.As soon as the electric arc 10 appears, a plasma gas, such as air, is injected into an injection chamber 11, between the electrodes 5 and 6. For this, the gas, coming from a circuit supply known per se and not shown, passes through a passage 12 formed in the body 1 then, transverse injection orifices 13 provided in a cylindrical part 14 surrounding the opposite ends of the electrodes, to then open into the chamber 11, the thermal plasma exiting through the downstream tubular electrode 6.

Pour éviter une usure prématurée des électrodes 5 et 6, la torche à plasma 1 comprend des moyens pour déplacer les pieds d'accrochage de l'arc électrique engendré autour des surfaces internes des électrodes tubulaires 5 et 6. Ces moyens sont définis par au moins une bobine électromagnétique 15 associée, dans ce mode de réalisation, au support 3 de l'électrode amont 5.To avoid premature wear of the electrodes 5 and 6, the plasma torch 1 comprises means for moving the attachment feet of the electric arc generated around the internal surfaces of the tubular electrodes 5 and 6. These means are defined by at least an electromagnetic coil 15 associated, in this embodiment, with the support 3 of the upstream electrode 5.

Selon l'invention, la bobine électromagnétique 15 est intégrée au circuit de refroidissement 8.1 de l'électrode 5. En se référant aux figures 1 et 2, on voit que le circuit de refroidissement 8.1 est défini par une chambre cylindrique étanche 16 prévue entre le support 3 et la surface externe 58 de l'électrode 5, en étant séparée, par la bobine électromagnétique 15, en deux espaces annulaires concentriques 16A et 16B à travers lesquels circule le fluide de refroidissement, lesdits espaces annulaires étant en communication l'un avec l'autre à l'extrémité aval 15A de ladite bobine 15.According to the invention, the electromagnetic coil 15 is integrated into the cooling circuit 8.1 of the electrode 5. With reference to FIGS. 1 and 2, it can be seen that the cooling circuit 8.1 is defined by a sealed cylindrical chamber 16 provided between the support 3 and the external surface 58 of the electrode 5, being separated, by the electromagnetic coil 15, into two concentric annular spaces 16A and 16B through which the coolant circulates, said annular spaces being in communication with one the other at the downstream end 15A of said coil 15.

La bobine électromagnétique 15 fait ainsi office de paroi de séparation des espaces annulaires 16A et 16B, de sorte que cet agencement n'implique aucun encombrement supplémentaire de la torche à plasma.The electromagnetic coil 15 thus acts as a partition wall for the annular spaces 16A and 16B, so that this arrangement does not involve any additional bulk of the plasma torch.

Le fluide de refroidissement est électriquement isolant tel que, par exemple, de l'eau désionisée. Ce fluide, issu d'un circuit d'alimentation connu en soi et non représenté, arrive par un conduit 27 débouchant dans la chambre étanche 16 pour circuler dans l'espace annulaire 16A, entre le support 3 et la bobine 15, puis dans l'espace annulaire 16B, entre la bobine 15 et la surface externe 58 de l'électrode, pour ressortir par un passage 5C prévu dans l'extrémité arrière 5D de l'électrode 5 en direction dudit circuit. La circulation du fluide est indiquée par des flèches F. On voit donc que la bobine électromagnétique 15, qui s'étend autour de l'électrode 5, est refroidie de façon optimale par le fluide de refroidissement.The cooling fluid is electrically insulating such as, for example, deionized water. This fluid, coming from a supply circuit known per se and not shown, arrives via a conduit 27 opening into the sealed chamber 16 to circulate in the annular space 16A, between the support 3 and the coil 15, then in the annular space 16B, between the coil 15 and the external surface 58 of the electrode, to emerge through a passage 5C provided in the rear end 5D of the electrode 5 in the direction of said circuit. The circulation of the fluid is indicated by arrows F. It can therefore be seen that the electromagnetic coil 15, which extends around the electrode 5, is cooled optimally by the cooling fluid.

Dans un mode préféré de réalisation illustré sur la figure 2, la bobine électromagnétique 15 est définie par deux enroulements concentriques 17A et 17B de spires jointives, obtenus à partir d'un fil métallique continu 17, par exemple en cuivre. Entre les deux enroulements de spires 17A et 17B est disposée une enveloppe de matière isolante 18 qui constitue ainsi une paroi étanche séparant les deux espaces annulaires 16A et 16B. Par ailleurs, on voit que le fil des spires formant les enroulements de la bobine 15 présente avantageusement une section rectangulaire pleine.In a preferred embodiment illustrated in FIG. 2, the electromagnetic coil 15 is defined by two concentric windings 17A and 17B of contiguous turns, obtained from a continuous metallic wire 17, for example made of copper. Between the two windings of turns 17A and 17B is placed an envelope of insulating material 18 which thus constitutes a sealed wall separating the two annular spaces 16A and 16B. Furthermore, it can be seen that the wire of the turns forming the windings of the coil 15 advantageously has a solid rectangular section.

La bobine 15 est fixée par l'une 20 de ses extrémités à une bague métallique 21 conformant une partie du circuit de refroidissement et interposée entre le support 5 et l'extrémité arrière 5D de l'électrode 5, tandis que l'autre extrémité 22 de la bobine, isolée de la masse métallique, est raccordée à une ligne d'alimentation électrique 23. Avantageusement, cette ligne d'alimentation 23 chemine à l'intérieur du conduit 27 d'amenée en fluide de refroidissement, de sorte qu'elle est ainsi efficacement refroidie.The coil 15 is fixed by one of its ends 20 to a metal ring 21 conforming to a part of the cooling circuit and interposed between the support 5 and the rear end 5D of the electrode 5, while the other end 22 of the coil, isolated from the metallic mass, is connected to an electrical supply line 23. Advantageously, this supply line 23 travels inside the duct 27 for supplying cooling fluid, so that it is thus effectively cooled.

Le circuit de refroidissement 8.2 de l'électrode aval 6 est alimenté en fluide de refroidissement par un conduit 24. Les diverses alimentations en gaz plasmagène et en fluide de refroidissement, ainsi que les alimentations électriques des électrodes et de la bobine, sont de type connu et sont reliées à un système de commande assurant le bon fonctionnement de la torche à plasma selon les modalités qui lui ont été assignées.The cooling circuit 8.2 of the downstream electrode 6 is supplied with cooling fluid by a conduit 24. The various supplies of plasma gas and of cooling fluid, as well as the electrical supplies of the electrodes and of the coil, are of known type. and are connected to a control system ensuring the proper functioning of the plasma torch according to the methods assigned to it.

Claims (8)

  1. Plasma torch of the type including:
    - two tubular and coaxial electrodes (5 and 6) in extension of each other, each electrode (5 and 6) being arranged in a support (3 and 4);
    - means (8.1, 8.2) for cooling the said electrodes, which means are passed through by a cooling fluid, the said means for cooling at least one of the said electrodes comprising a leaktight cylindrical chamber (16), provided in the corresponding support and separated by a cylindrical separating wall dividing the chamber into two annular spaces (16A and 16B) in communication with each other at one end of the said wall and through which the said cooling fluid flows;
    - means (9) for igniting an electric arc between the two electrodes;
    - means (11, 12, 13) for injecting a plasma-generating gas between the two electrodes; and,
    - electromagnetic coil means (15) for displacing the anchoring feet (10.1, 10.2) of the electric arc (10) over the internal surfaces of the said electrodes,
    characterized in that the fluid for cooling the said electrode, the leaktight chamber (16) of which includes the separating wall, is electrically insulating and in that the said electromagnetic coil (15) acts as the said cylindrical separating wall.
  2. Plasma torch according to Claim 1, characterized in that the said electromagnetic coil (15) is combined with the support (3) surrounding the electrode (5) which is upstream with respect to the flow of the plasma-generating gas.
  3. Plasma torch according to one of Claims 1 or 2, characterized in that the said electromagnetic coil (15) extends approximately over the entire length of the electrode.
  4. Plasma torch according to any one of the preceding Claims 1 to 3, characterized in that the said electromagnetic coil (15) is defined by two concentric windings (17A and 17B) of adjoining turns, an envelope of insulating material (18) being interposed between the two concentric windings of turns.
  5. Plasma torch according to Claim 4, characterized in that the two windings of turns are obtained from a continuous metal wire (17).
  6. Plasma torch according to Claim 5, characterized in that the wire of the coil has a rectangular cross-section.
  7. Plasma torch according to any one of the preceding Claims 1 to 6, characterized in that the said electromagnetic coil is connected by one (22) of its ends to an electrical supply line (23) and by the other end (20) to a ring (21) integral with the said corresponding support.
  8. Plasma torch according to Claim 7, characterized in that the said electrical supply line (23) runs through the pipe (27) for supplying the electrically insulating cooling fluid.
EP90403044A 1989-11-08 1990-10-29 Plasma torch with electromagnetic coil for rotating the arc Expired - Lifetime EP0427590B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8914675A FR2654295B1 (en) 1989-11-08 1989-11-08 PLASMA TORCH PROVIDED WITH AN ELECTROMAGNETIC COIL FOR ROTATING ARC FEET.
FR8914675 1989-11-08

Publications (2)

Publication Number Publication Date
EP0427590A1 EP0427590A1 (en) 1991-05-15
EP0427590B1 true EP0427590B1 (en) 1994-08-24

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Application Number Title Priority Date Filing Date
EP90403044A Expired - Lifetime EP0427590B1 (en) 1989-11-08 1990-10-29 Plasma torch with electromagnetic coil for rotating the arc

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US (1) US5132511A (en)
EP (1) EP0427590B1 (en)
JP (1) JP3006720B2 (en)
KR (1) KR0146046B1 (en)
AT (1) ATE110515T1 (en)
CA (1) CA2029508C (en)
DE (1) DE69011814T2 (en)
DK (1) DK0427590T3 (en)
ES (1) ES2060984T3 (en)
FR (1) FR2654295B1 (en)

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Publication number Priority date Publication date Assignee Title
US5374801A (en) * 1993-11-15 1994-12-20 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Plasma heating for containerless and microgravity materials processing
FR2735941B1 (en) * 1995-06-23 1997-09-19 Aerospatiale PLASMA TORCH WITH ELECTROMAGNETIC COIL FOR INDEPENDENT AND INTEGRATED ARCH FOOT MOVEMENT
FR2735940B1 (en) * 1995-06-23 1997-09-19 Aerospatiale PLASMA TORCH WITH A SUBSTANTIALLY AXI-SYMMETRICAL STRUCTURE
US6897402B2 (en) * 2002-04-24 2005-05-24 Thermal Spray Technologies, Inc. Plasma-arc spray anode and gun body
DE102009005078A1 (en) 2009-01-16 2010-02-18 Daimler Ag Plasma spray assembly for automotive crankshaft bearing has a circular non-sacrificial electrode surrounded by electromagnetic coils

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3832519A (en) * 1972-08-11 1974-08-27 Westinghouse Electric Corp Arc heater with integral fluid and electrical ducting and quick disconnect facility
US3924092A (en) * 1974-06-14 1975-12-02 Westinghouse Electric Corp Method and apparatus for cladding a base metal
DE2633510C3 (en) * 1976-08-16 1979-12-20 Kischinevskij Politechnitscheskij Institut Imeni S. Lazo Plasmatron
US4219726A (en) * 1979-03-29 1980-08-26 Westinghouse Electric Corp. Arc heater construction with total alternating current usage
US4227031A (en) * 1979-05-18 1980-10-07 Paton Boris E Nonconsumable electrode for melting metals and alloys
FR2473248A1 (en) * 1980-01-07 1981-07-10 Commissariat Energie Atomique IONIZED GAS GENERATOR WITH VERY HIGH PRESSURE AND VERY HIGH TEMPERATURE
US4535225A (en) * 1984-03-12 1985-08-13 Westinghouse Electric Corp. High power arc heater
US4668853A (en) * 1985-10-31 1987-05-26 Westinghouse Electric Corp. Arc-heated plasma lance

Also Published As

Publication number Publication date
ES2060984T3 (en) 1994-12-01
JP3006720B2 (en) 2000-02-07
KR910011095A (en) 1991-06-29
CA2029508C (en) 2000-05-02
FR2654295B1 (en) 1992-02-14
JPH03171599A (en) 1991-07-25
DE69011814T2 (en) 1994-12-22
FR2654295A1 (en) 1991-05-10
US5132511A (en) 1992-07-21
EP0427590A1 (en) 1991-05-15
CA2029508A1 (en) 1991-05-09
ATE110515T1 (en) 1994-09-15
DE69011814D1 (en) 1994-09-29
DK0427590T3 (en) 1994-09-19
KR0146046B1 (en) 1998-08-17

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