US3504219A - Non-consumable electrode for plasma jet torches - Google Patents

Non-consumable electrode for plasma jet torches Download PDF

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Publication number
US3504219A
US3504219A US558030A US3504219DA US3504219A US 3504219 A US3504219 A US 3504219A US 558030 A US558030 A US 558030A US 3504219D A US3504219D A US 3504219DA US 3504219 A US3504219 A US 3504219A
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US
United States
Prior art keywords
plasma jet
cathode
gas
torch
anode
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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
US558030A
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English (en)
Inventor
Tetsuo Gejo
Toshikatsu Manabe
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Hitachi Ltd
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Hitachi Ltd
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Publication date
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/06—Electrodes
    • H05B7/08—Electrodes non-consumable
    • 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
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/222—Non-consumable 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

Definitions

  • This invention relates to techniques for generating plasma jets, and more particularly to improvements in plasma jet torches. More specifically, the invention concerns a new and improved plasma jet torch capable of using air in an arc gas.
  • Various methods are known for generating plasma jets. Examples of these methods are: the method wherein arc discharge, glow discharge, or the like is caused within a body of gas; the method wherein a high-frequency electric field is applied to a gas to ionize the gas; and the method wherein a gas is ionized through the use of an agent such as light, radiation, or heat.
  • a plasma jet of particularly high energy can be obtained, and this plasma jet can be utilized for fabrication of articles from various materials, supplying of heat, and so forth.
  • Another object of the invention is to provide a plasma jet torch of the above stated character which has a simple construction and can be produced at relatively low cost.
  • a plasma jet torch characterized in that the electrodes in entirety or at least in the parts thereof exposed to the arc gas and heat are made of zirconium boride (ZrB whereby an oxidizing gas such as air can be used in the arc gas.
  • ZrB zirconium boride
  • FIGURES 1(a) and 1(b) are simplified views in vertical section showing the electrodes and essential surrounding parts of known plasma jet torches;
  • FIGURES 2(a) and 2(b) are vertical sectional views respectively showing the anode and cathode of a plasma jet torch embodying the invention.
  • FIGURE 3 is a vertical sectional view showing the electrodes and essential surrounding parts of a preferred embodiment of the plasma jet torch according to the invention.
  • FIGURES 1(a) and 1(b) are shown specific examples of known devices for generating plasma jets by 3,504,219 Patented Mar. 31, 1970 are discharge.
  • FIGURE 1(a) shows a plasma jet torch of the so-called transfer type, in which there are provided a cathode 1 and a nozzle 2 in which the cathode 1 is coaxially disposed, and which is provided with a circulation passage 4 for electrode cooling water, are gas being introduced through the annular space 5 between the cathode 1 and the nozzle 2.
  • an arc discharge is created between the cathode 1 and a workpiece 6, and an arc gas is introduced into the part where the arc discharge has been created to eject the arc together with the arc gas out through the nozzle thereby to produce a plasma jet 3 in the form of a flame.
  • FIGURE 1(b) illustrates an example of a plasma jet torch of the so-called nontransfer type, in which the nozzle structure 2 functions additionally as an anode. An electric discharge is created between the nozzle 2 and the cathode 1, and a plasma jet 3 is produced in a manner similar to that in the example of the transfer type shown in FIGURE 1(a).
  • gas a reducing gas or an inert gas such as argon, hydrogen, or nitrogen is generally used.
  • gases are expensive and give rise to economic disadvantage particularly in cases where a large quantiity of arc gas is required as in the working of materials.
  • a plasma jet torch which can be effectively operated with the use of an oxidizing arc gas, particularly air.
  • a plasma jet torch can be provided by constructing the electrodes entirely, or at least those parts which are to be contacted by the arc gas, of zirconium boride (ZrB).
  • ZrB zirconium boride
  • the sintered cylinder thus obtained is machined into a cathode having a bullet head at one end and a small diameter projection at the other end as shown in FIG- URE 2(b).
  • This machined cathode is further sintered at 2,400 degrees C. for one hour in the Tammann furnace, whereupon the cathode 11 is completed.
  • a moulded ZrB cylinder of SS-mm. diameter and 30-min. length is made and machined into an anode 12 having a center nozzle and a support flange around its periphery as shown in FIGURE 2(a).
  • FIGURE 3 An example of a plasma jet torch in which these electrodes are used is shown in FIGURE 3.
  • the cathode 11 is mounted on the end of a centrally disposed cathode support 17 made of a material such as copper
  • the anode 12 functioning additionally as a nozzle is mounted, coaxially with the cathode 11, on a cylindrical anode support 18 also made of a material such as copper.
  • An annular electrical insulator 19 is disposed concentrically inside the anode support 18 at a position to surround the cathode 11 and to join the inner end of the nozzle 12.
  • Another annular insulator 20 is disposed between the cathode support 17 and the anode support 18 at the lower part of the cathode support 17.
  • the anode support 18 is provided with a positive connection 22 for connection to a power source.
  • tungsten and copper are used for the cathode and anode, respectively, as mentioned hereinbefore.
  • the anode may be made of ZrB and the cathode may be made of a material such as tungsten as in the conventional practice.
  • a plasma jet torch in which an arc gas containing air is used, said torch comprising an anode functioning additionally as a jet nozzle, a cathode, said anode and cathode including parts exposed simultaneously to heat and the arc gas, said parts being made of zirconium boride, means to supply the arc gas past the cathode and through the anode, and means to apply electric power to the anode and cathode.
  • a plasma jet torch for using reactive gas comprising a non-consumable electrode including at least one portion consisting of zirconium boride.
  • a conventional torch employing tungsten and copper electrodes was used to generate a plasma jet under the same operational conditions as described above, whereupon it was found that the surface of the tungsten cathode was severely oxidized and that white tungsten oxide had formed on the surface. Furthermore, the nozzle part of the copper anode. was found to be severely eroded.
  • the plasma jet torch according to the present invention has excellent oxidation resistance, and, moreover, since the operational parts thereof are made of an electrically conductive ceramic having high thermionic emissivity, the plasma jet torch of the invention produces excellent results through the use of air in the arc gas.
  • a torch according to claim 2 wherein said electrode includes parts adapted to contact the reactive gas and parts shielded from said reactive gas and wherein said electrode is of zirconium boride in only those parts which contact with the reactive gas.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Mechanical Engineering (AREA)
  • Arc Welding In General (AREA)
  • Plasma Technology (AREA)
US558030A 1965-06-30 1966-06-16 Non-consumable electrode for plasma jet torches Expired - Lifetime US3504219A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1965052897U JPS441240Y1 (de) 1965-06-30 1965-06-30

Publications (1)

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US3504219A true US3504219A (en) 1970-03-31

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US558030A Expired - Lifetime US3504219A (en) 1965-06-30 1966-06-16 Non-consumable electrode for plasma jet torches

Country Status (4)

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US (1) US3504219A (de)
JP (1) JPS441240Y1 (de)
DE (1) DE1264641B (de)
GB (1) GB1145570A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4392047A (en) * 1980-05-14 1983-07-05 Bykhovskij David G Non-consumable electrode
EP0428150A1 (de) * 1989-11-14 1991-05-22 Asahi Glass Company Ltd. Bodenelektrode für Gleichstromlichtbogenofen
US6583378B1 (en) * 1999-11-26 2003-06-24 Komatsu Industries Corporation Plasma machining electrode and plasma machining device
DE10323014A1 (de) * 2003-04-23 2004-11-25 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Düse für Plasmabrenner
US20220104337A1 (en) * 2018-11-30 2022-03-31 Oerlikon Metco (Us) Inc. Electrode for plasma a gun

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5230742A (en) * 1975-09-04 1977-03-08 Kubota Ltd Plasma cutting nozzle

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1850689A (en) * 1928-08-13 1932-03-22 Fed Telegraph Co Oscillation generator process and apparatus
US2157498A (en) * 1936-02-01 1939-05-09 Bernhard Berghaus Apparatus for the production of metallic coatings
GB802905A (en) * 1954-01-14 1958-10-15 British Aluminium Co Ltd Improvements in or relating to electrolytic cells for the production of aluminium
US3042830A (en) * 1960-04-04 1962-07-03 Mhd Res Inc Method and apparatus for effecting gas-stabilized electric arc reactions
US3077108A (en) * 1958-02-20 1963-02-12 Union Carbide Corp Supersonic hot gas stream generating apparatus and method
US3093567A (en) * 1959-03-30 1963-06-11 Gen Motors Corp Nuclear device for generating electric power
US3198932A (en) * 1962-03-30 1965-08-03 Union Carbide Corp Arc electrode
US3250893A (en) * 1963-10-01 1966-05-10 Union Carbide Corp Method for providing a source of heat
US3274408A (en) * 1963-05-14 1966-09-20 Avco Corp High temperature anisotropic nonconsumable electrode
US3314876A (en) * 1960-11-28 1967-04-18 British Aluminium Co Ltd Method for manufacturing solid current conducting elements

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1850689A (en) * 1928-08-13 1932-03-22 Fed Telegraph Co Oscillation generator process and apparatus
US2157498A (en) * 1936-02-01 1939-05-09 Bernhard Berghaus Apparatus for the production of metallic coatings
GB802905A (en) * 1954-01-14 1958-10-15 British Aluminium Co Ltd Improvements in or relating to electrolytic cells for the production of aluminium
US3077108A (en) * 1958-02-20 1963-02-12 Union Carbide Corp Supersonic hot gas stream generating apparatus and method
US3093567A (en) * 1959-03-30 1963-06-11 Gen Motors Corp Nuclear device for generating electric power
US3042830A (en) * 1960-04-04 1962-07-03 Mhd Res Inc Method and apparatus for effecting gas-stabilized electric arc reactions
US3314876A (en) * 1960-11-28 1967-04-18 British Aluminium Co Ltd Method for manufacturing solid current conducting elements
US3198932A (en) * 1962-03-30 1965-08-03 Union Carbide Corp Arc electrode
US3274408A (en) * 1963-05-14 1966-09-20 Avco Corp High temperature anisotropic nonconsumable electrode
US3250893A (en) * 1963-10-01 1966-05-10 Union Carbide Corp Method for providing a source of heat

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4392047A (en) * 1980-05-14 1983-07-05 Bykhovskij David G Non-consumable electrode
EP0428150A1 (de) * 1989-11-14 1991-05-22 Asahi Glass Company Ltd. Bodenelektrode für Gleichstromlichtbogenofen
US5142650A (en) * 1989-11-14 1992-08-25 Asahi Glass Company Ltd. Bottom electrode for a direct current arc furnace
US6583378B1 (en) * 1999-11-26 2003-06-24 Komatsu Industries Corporation Plasma machining electrode and plasma machining device
DE10323014A1 (de) * 2003-04-23 2004-11-25 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Düse für Plasmabrenner
US20070056936A1 (en) * 2003-04-23 2007-03-15 Volker Krink Nozzle for plasma torches
DE10323014B4 (de) * 2003-04-23 2007-11-22 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Düse für Plasmabrenner
US7645959B2 (en) 2003-04-23 2010-01-12 Kjellberg Finsterwalde Plasma Und Maschinen Gmbh Nozzle for plasma torches
US20220104337A1 (en) * 2018-11-30 2022-03-31 Oerlikon Metco (Us) Inc. Electrode for plasma a gun

Also Published As

Publication number Publication date
GB1145570A (en) 1969-03-19
JPS441240Y1 (de) 1969-01-18
DE1264641B (de) 1968-03-28

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