US3515839A - Plasma torch - Google Patents

Plasma torch Download PDF

Info

Publication number
US3515839A
US3515839A US717731A US3515839DA US3515839A US 3515839 A US3515839 A US 3515839A US 717731 A US717731 A US 717731A US 3515839D A US3515839D A US 3515839DA US 3515839 A US3515839 A US 3515839A
Authority
US
United States
Prior art keywords
cathode
plasma
nozzle
discharge
torch
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
US717731A
Other languages
English (en)
Inventor
Tetuo Gejo
Tosikatu Manabe
Yasuzi Hamura
Kotaro Uchimura
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Application granted granted Critical
Publication of US3515839A publication Critical patent/US3515839A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
    • B23K35/0205—Non-consumable electrodes; C-electrodes
    • 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
    • H05H1/3442—Cathodes with inserted tip

Definitions

  • a plasma jet torch provided with a cathode made of tungsten or an alloy including tungsten as a principal component and whose surfaces are covered with tungsten silicide coating. According to said plasma jet torch, the rate of oxidation of the cathode when a plasma jet flame is generated with oxidizing arc gas can be reduced remarkably.
  • This invention relates to a plasma torch for generating an intense plasma flame and more particularly to a plasma torch comprising an improved electrode.
  • Various methods of generating a plasma flame are known. Among them, a method of generating are discharge or glow discharge and feeding work gas during the discharge is suitable for generating a particularly high energy plasma flame.
  • the plasma flame provided in this way has a wide range of application in the processing of various materials (welding, spraying, cutting, etc.) and as a variety of heat sources.
  • a torch discharge device composed of a cathode, a nozzle for ejecting a work gas provided in a way to surround said cathode and a power supply for causing a discharge between said cathode and said nozzle or between the other parts.
  • a method of providing a plasma flame by generating arc discharge between said cathode and said nozzle and feeding a work gas to said discharge spot is called a non-transfer type method while a method of providing a plasma flame by generating discharge between said cathode and a part to be processed and feeding work gas to said discharge spot is called a transfer type method.
  • Such methods of generating a plasma flame which utilize arc discharge or glow discharge are advantageous in that a very high energy plasma flame is easily obtained.
  • the temperature of the cathode and the nozzle becomes quite high, electrode materials having a high electroemissivity, a good thermal conductivity and a high melting point are necessary and, for example, thoriated tungsten has been mainly used.
  • work gas non-oxidizing gas like argon, hydrogen, or nitrogen must be used.
  • An object of this invention is to provide a plasma torch comprising a cathode having a slow rate of oxidation suflicient to use oxidizing gas like air as work gas.
  • the plasma torch according to this invention comprises a cathode made of tungsten or an alloy including tung- Patented June 2, 1970 sten (e.g., thoriated tungsten) as a principal component whose surface is coated with tungsten silicide.
  • a cathode made of tungsten or an alloy including tung- Patented June 2, 1970 sten (e.g., thoriated tungsten) as a principal component whose surface is coated with tungsten silicide.
  • the cathode of this invention coated with tungsten silicide is provided, for example, by making gaseous silicon compounds react with a cathode material shaped into a predetermined form at a high temperature and forming a tungsten silicide layer on the cathode surface. All-- other method wherein a tungsten silicide layer is formed by spraying a plasma flame is also effective.
  • FIG. 1 shows a schematic longitudinal sectional diagram of a cathode and a nozzle of a transfer type plasma torch according to an embodiment of this invention.
  • FIG. 2 is a schematic longitudinal sectional diagram of a cathode and a nozzle of a non-transfer type plasma torch according to another embodiment of the invention.
  • FIG. 3 is a schematic longitudinal sectional diagram of a plasma torch according to a further embodiment of the invention.
  • FIG. 4 shows the relation between the thickness of a tungsten silicide layer and the rate of oxidation.
  • FIG. 1 is a schematic longitudinal sectional diagram of a transfer type plasma torch according to an embodiment of this invention.
  • a transfer type plasma torch In a transfer type plasma torch. the inner walls of a nozzle 2 are maintained at a lower temperature than an electrode 1 in order to generate dis charge between a work piece 6 and the electrode 1 and to generate a plasma flame 3 by feeding discharge gas to the discharge member from the discharge gas inlet 5.
  • the oxidation of the inner walls of the nozzle 2 can almost be diminished. Accordingly, in many cases of a transfer type plasma torch, an oxidizing work gas can be used if a tungsten silicide coat-- ing 7 is provided to the cathode concentrically at the discharge spot.
  • FIG. 2 is a longitudinal sectional diagram of a nontransfer type plasma torch according to another embodiment of the invention.
  • discharge 8 takes place between the cathode 1 and the nozzle 2. Therefore, it is preferable to provide an oxidation resisting coating 9 made, for example, of Zirconia or alumina to the inner walls of the nozzle 2.
  • an oxidation resisting coating 9 made, for example, of Zirconia or alumina to the inner walls of the nozzle 2.
  • a cathode is formed by shaving one end of a tungsten bar including 2% thalium into a bullet shape and shaving the other end planely while pro viding a protrusion at the center.
  • the size of the cathode is of the order of 15 mm. in length, 6 mm. in diameter, 3R in curvature at the top end part and 2 mm. x 4 mm. at the protruding part.
  • the cathode formed in the way described hereinabove is heated in hydrogen gas flow of about 0.5 L/min. Then, hydrogen is made to bubble through silicon tetrachloride liquid held at about 20 C. at the rate of about 0.2 L/min. and is fed to the heated cathode. When silicon tetrachloride vapour is made to react with the heated cathode, a tungsten silicide layer of about 0.3 mm. in thickness is formed on the cathode in about 30 minutes.
  • FIG. 3 An example of a plasma jet torch in which such cathode is used is shown in FIG. 3. As shown, the cathode 11 is mounted on the end of a centrally disposed cathode support 17 made of a material such as copper, and the anode 12 functioning additionally as a nozzle is mounted,
  • an annular electrical insulator 19 is disposed concentrically inside the anode support 18 in a way to surround the cathode 11 and to join the inner end of the nozzle 12. Between the nozzle 12 and the support 18 thereof a path 14 through which a cooling water is circulated is formed. Means for supplying the cooling water to the path 14 and means for exhausting the cooling water therefrom are not shown.
  • Another annular insulator is disposed between the cathode support 17 and the support 18 at the lower part of the cathode support 17. Arc gas is introduced into the torch through. an inlet 21.
  • the anode support 18 is provided with a positive connection 22 for connection to a power source (not shown).
  • a torch employing tungsten silicide electrode 23 as described above was used to generate a plasma jet flame under the operational conditions of a current of 300 amps, a voltage of 50 volts, an arc gas consisting of a mixture of argon of a flow rate of 30 liters/min. and air at a flow rate of 20 liters/min. and an electrode gap of 7 mm.
  • the rate of oxidation in this embodiment was 0.15 mm./min.
  • theh rate of oxidation is as large as 3.0 mm./min.
  • FIG. 4 is a curve showing the relation between the thickness of a tungsten silicide layer and the rate of oxidation. It will be apparent from this figure that the rate of oxidation becomes nearly constant when the thickness of the tungsten silicide layer exceeds 0.1 mm.
  • the direct contact between the oxidizing component in work gas and tungsten or tungsten alloy composing a cathode can be prevented due to a tungsten silicide layer provided on the surface of the electrode and the oxidation resisting power of the electrode can be strengthened.
  • a plasma jet torch comprising a cathode, means for supporting said cathode, a nozzle concentrically surrounding said cathode and said supporting means and having a jet orifice for work gas in front of said cathode, means for feeding work gas to said jet orifice, and means for generating discharge between said cathode and said nozzle, wherein said cathode is composed essentially of tungsten and the surface thereof at the portion comprising the discharge spot has a tungsten silicide coating.
  • a plasma jet torch having discharging electrodes beween which a discharge is produced, one of the discharging electrodes being a cathode, a cathode support member, a nozzle concentrically surrounding said cathode and said cathode support member and having a jet orifice for work gas provided in front of said cathode, and means for feeding work gas to said jet orifice, wherein said cathode is composed essentially of tungsten and the surface thereof at the portion comprising the discharge spot has a tungsten silicide coating.
  • a plasma jet torch according to claim 1, wherein a coating made of an oxidation resisting material is provided on the inner walls of said nozzle and around said jet orifice for the plasma flame.
  • a plasma jet torch comprising a cathode, means for supporting said cathode, a nozzle concentrically surrounding said cathode and said supporting means and having a jet orifice for work gas in front of said cathode, means for feeding work gas to said jet orifice, and means for generating discharge between said cathode and an electrode in front of said nozzle, wherein said cathode is composed essentially of tungsten and the surface thereof at the portion comprising the discharge spot has a tungsten silicide coating.
  • a plasma torch according to claim 5 wherein a coating made of an oxidation resisting material is provided on the inner walls of said nozzle and around said jet orifice for the plasma flame.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Mechanical Engineering (AREA)
  • Plasma Technology (AREA)
US717731A 1967-04-07 1968-04-01 Plasma torch Expired - Lifetime US3515839A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2182667 1967-04-07

Publications (1)

Publication Number Publication Date
US3515839A true US3515839A (en) 1970-06-02

Family

ID=12065849

Family Applications (1)

Application Number Title Priority Date Filing Date
US717731A Expired - Lifetime US3515839A (en) 1967-04-07 1968-04-01 Plasma torch

Country Status (2)

Country Link
US (1) US3515839A (de)
DE (1) DE1764116B1 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2537479A1 (fr) * 1982-12-09 1984-06-15 Prunier Robert Perfectionnements aux equipements d'usinage electrique par fusion metallique
EP0194634A2 (de) * 1985-03-14 1986-09-17 The Perkin-Elmer Corporation Plasmabrenner mit langer Lebensdauer
DE19532412A1 (de) * 1995-09-01 1997-03-06 Agrodyn Hochspannungstechnik G Verfahren und Vorrichtung zur Oberflächen-Vorbehandlung von Werkstücken
US20070284340A1 (en) * 2006-06-09 2007-12-13 Morten Jorgensen Vortex generator for plasma treatment
WO2010067306A2 (fr) 2008-12-09 2010-06-17 Advanced Machines Sàrl Dispositif et procédé de génération d'un flux de plasma
US20100170641A1 (en) * 2006-06-09 2010-07-08 3Dt Llc Plasma treatment method and apparatus
FR3107159A1 (fr) * 2020-02-10 2021-08-13 Akryvia Torche plasma à amorcage direct et tuyère à barrière diélectrique correspondante

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3328777A1 (de) * 1983-08-10 1985-02-28 Fried. Krupp Gmbh, 4300 Essen Plasmabrenner und verfahren zu dessen betreiben
DE3426410A1 (de) * 1984-07-18 1986-01-23 Süddeutsche Kühlerfabrik Julius Fr. Behr GmbH & Co KG, 7000 Stuttgart Schweissbrenner zum plasma-mig-schweissen
DE3435680A1 (de) * 1984-09-28 1986-04-03 Fried. Krupp Gmbh, 4300 Essen Plasmabrenner
SE452862B (sv) * 1985-06-05 1987-12-21 Aga Ab Ljusbagselektrod
DE3544657A1 (de) * 1985-12-17 1987-06-19 Plasmainvent Ag Hochstromelektrode

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744183A (en) * 1952-11-13 1956-05-01 Union Carbide & Carbon Corp Inert gas-shielded arc welding
US2922028A (en) * 1957-11-25 1960-01-19 Union Carbide Corp Electric arc electrodes
US3106631A (en) * 1961-04-21 1963-10-08 Union Carbide Corp Arc torch device
US3198932A (en) * 1962-03-30 1965-08-03 Union Carbide Corp Arc electrode
US3206587A (en) * 1963-02-13 1965-09-14 Kugler Tibor Plasma-jet-gun
US3214623A (en) * 1962-02-12 1965-10-26 Sheer Korman Associates Fluid transpiration plasma jet
US3307011A (en) * 1963-08-29 1967-02-28 Union Carbide Corp Method for increasing electrode life
US3329865A (en) * 1966-01-19 1967-07-04 Vitro Corp Of America Radiant plasma source having a gas impervious conical anode

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1421353A (fr) * 1964-08-19 1965-12-17 Saint Gobain Perfectionnements aux électrodes réfractaires pour arcs électriques de forte intensité

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744183A (en) * 1952-11-13 1956-05-01 Union Carbide & Carbon Corp Inert gas-shielded arc welding
US2922028A (en) * 1957-11-25 1960-01-19 Union Carbide Corp Electric arc electrodes
US3106631A (en) * 1961-04-21 1963-10-08 Union Carbide Corp Arc torch device
US3214623A (en) * 1962-02-12 1965-10-26 Sheer Korman Associates Fluid transpiration plasma jet
US3198932A (en) * 1962-03-30 1965-08-03 Union Carbide Corp Arc electrode
US3206587A (en) * 1963-02-13 1965-09-14 Kugler Tibor Plasma-jet-gun
US3307011A (en) * 1963-08-29 1967-02-28 Union Carbide Corp Method for increasing electrode life
US3329865A (en) * 1966-01-19 1967-07-04 Vitro Corp Of America Radiant plasma source having a gas impervious conical anode

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2537479A1 (fr) * 1982-12-09 1984-06-15 Prunier Robert Perfectionnements aux equipements d'usinage electrique par fusion metallique
EP0194634A2 (de) * 1985-03-14 1986-09-17 The Perkin-Elmer Corporation Plasmabrenner mit langer Lebensdauer
EP0194634A3 (de) * 1985-03-14 1987-11-19 The Perkin-Elmer Corporation Plasmabrenner mit langer Lebensdauer
DE19532412A1 (de) * 1995-09-01 1997-03-06 Agrodyn Hochspannungstechnik G Verfahren und Vorrichtung zur Oberflächen-Vorbehandlung von Werkstücken
EP0761415A2 (de) * 1995-09-01 1997-03-12 Agrodyn Hochspannungstechnik GmbH Verfahren und Vorrichtung zur Oberflächen-Vorbehandlung von Werkstücken
EP0761415A3 (de) * 1995-09-01 1998-01-28 Agrodyn Hochspannungstechnik GmbH Verfahren und Vorrichtung zur Oberflächen-Vorbehandlung von Werkstücken
US5837958A (en) * 1995-09-01 1998-11-17 Agrodyn Hochspannungstechnik Gmbh Methods and apparatus for treating the surface of a workpiece by plasma discharge
DE19532412C2 (de) * 1995-09-01 1999-09-30 Agrodyn Hochspannungstechnik G Vorrichtung zur Oberflächen-Vorbehandlung von Werkstücken
US20070284340A1 (en) * 2006-06-09 2007-12-13 Morten Jorgensen Vortex generator for plasma treatment
US7547861B2 (en) 2006-06-09 2009-06-16 Morten Jorgensen Vortex generator for plasma treatment
US20100170641A1 (en) * 2006-06-09 2010-07-08 3Dt Llc Plasma treatment method and apparatus
WO2010067306A2 (fr) 2008-12-09 2010-06-17 Advanced Machines Sàrl Dispositif et procédé de génération d'un flux de plasma
EP2613614A1 (de) 2008-12-09 2013-07-10 Advanced Machines Sàrl Vorrichtung zur Erzeugung eines Plasmaflusses
US8847101B2 (en) 2008-12-09 2014-09-30 Advanced Machine Sarl Device and method for generating a plasma flow
FR3107159A1 (fr) * 2020-02-10 2021-08-13 Akryvia Torche plasma à amorcage direct et tuyère à barrière diélectrique correspondante
WO2021160450A1 (fr) * 2020-02-10 2021-08-19 Akryvia Torche plasma à amorcage direct et tuyère à barrière diélectrique correspondante

Also Published As

Publication number Publication date
DE1764116B1 (de) 1971-03-04

Similar Documents

Publication Publication Date Title
US4564740A (en) Method of generating plasma in a plasma-arc torch and an arrangement for effecting same
US4788402A (en) High power extended arc plasma spray method and apparatus
US6388227B1 (en) Combined laser and plasma-arc processing torch and method
US4777343A (en) Plasma arc apparatus
US2982845A (en) Electric arc spraying
US2951143A (en) Arc torch
US3684911A (en) Plasma-jet generator for versatile applications
US3562486A (en) Electric arc torches
US3515839A (en) Plasma torch
US4439662A (en) Method of operating a plasma generating apparatus
US6172323B1 (en) Combined laser and plasma arc welding machine
US4977305A (en) System for low voltage plasma arc cutting
US3204076A (en) Electric arc torch
US3707615A (en) Nozzle for a plasma generator
US3148263A (en) Plasma-jet torch apparatus and method relating to increasing the life of the downstream electrode
US4851636A (en) Method and apparatus for generating an ultra low current plasma arc
US4343983A (en) Non-consumable composite welding electrode
US6087616A (en) Method for the plasmic arc-welding of metals
US3614376A (en) Plasma torch
US3344256A (en) Method for producing arcs
US3250893A (en) Method for providing a source of heat
US3472995A (en) Electric arc torches
JPS63154272A (ja) プラズマト−チ
GB866106A (en) Improved arc working process and apparatus
US1911033A (en) Atomic gas torch