US3194941A - High voltage arc plasma generator - Google Patents

High voltage arc plasma generator Download PDF

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Publication number
US3194941A
US3194941A US223484A US22348462A US3194941A US 3194941 A US3194941 A US 3194941A US 223484 A US223484 A US 223484A US 22348462 A US22348462 A US 22348462A US 3194941 A US3194941 A US 3194941A
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US
United States
Prior art keywords
arc
nozzle
electrode
torch
gas
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
US223484A
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English (en)
Inventor
Robert J Baird
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.)
Union Carbide Corp
Original Assignee
Union Carbide Corp
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
Priority to NL297831D priority Critical patent/NL297831A/xx
Priority to NL134809D priority patent/NL134809C/xx
Application filed by Union Carbide Corp filed Critical Union Carbide Corp
Priority to US223484A priority patent/US3194941A/en
Priority to GB33987/63A priority patent/GB1007429A/en
Priority to NO150072A priority patent/NO115114B/no
Priority to DEU4141U priority patent/DE1916912U/de
Application granted granted Critical
Publication of US3194941A publication Critical patent/US3194941A/en
Anticipated expiration legal-status Critical
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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
    • H05H1/3478—Geometrical details
    • 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

  • Electric arcs have been used for many years for cutting, for plating and welding processes and of recent years for metal melting furnaces, metal scarling, and metal cutting. In applications such as these, it is oftentimes preferable to operate the arc in a transferred mode; that is, having the work in the arc circuit.
  • This mode of operation has the advantage of more fully utilizing the heat energy -of the arc in the workpiece rather than having a portion of it dissipated to a separate electrode.
  • I-t is the main object of the invention to provide a method 4and apparatus for producing a high voltage arc plasma for use in electric arc working of materials.
  • an -apparatus having a cup shaped electrode, a gas directing nozzle having an L/ LD. of at least about 1.2 spaced from the cup shaped electrode, and a chamber surrounding the space between the cup electrode and the nozzle and having means for introducing ⁇ an arc gas into the chamber to produce a vortical ilow in the chamber and in the gas directing nozzle.
  • L the length of the nozzle is measured from the nozzle exit to end of the chamber nearest the exit.
  • the inside diameter (LD.) is the minimum inside diameter of ⁇ the nozzle.
  • the invention provides a novel process for generating .a high voltage, high temperature arc plasma for working materials.
  • a cup shaped electrode and the material to be worked are connected in circuit relation.
  • a high voltage arc is established between the cup-electrode and the material to be worked.
  • a vortical ilow of arc gas is provided in the region of the arc to form .an arc plasma.
  • the arc plasma is then passed through a gas directing nozzle having an L/I.D. of at least 'about 1.2.
  • the vortical flow of arc gas is maintained inside the gas directing nozzle to fcollimate ⁇ and direct the arc plasma.
  • the so-collimated and directed arc palsma is applied to the material to be treated.
  • the method and apparatus of the invention fulfills a long felt need for -a high power high voltage electric arc plasma generator for use in a transferred mode and having minimum electrode erosion.
  • the torch T primarily consi-sts of a cup shaped electrode 14 that is in axial alignment with a gas directing nozzle 16 and which is separated therefrom by an arc chamber 10.
  • Chamber 10 is electrically insulated from the electrode 14 by insulator 11.
  • Arc gas is introduced to torch T through inlet 13. From inlet 13 the arc gas passes through passage 18 down to a plurality of tangential apertures 12, through such apertures into the chamber 10.
  • the torch T is cooled by passing -a cooling fluid from coolant inlet 20 through passage 22 into a second passage 24 formed between the nozzle 16 and member 26. From passage 24 the coolant passes from the torch through chamber 28 and passage 30- and outlet 32.
  • the electrode 14 is also cooled by introducing a coolant through inlet 34 down passage 36 -through passage 38 down passage 39 and back up passage 41 through cross-passage 43 and out passage 40.
  • the outer tubular member 42 which deiines the passage 36 also carries means for connecting a power supply to the torch T. Therefore such member 42 is insulated from the remainder of torch T by insulator 44.
  • a quantity of arc gas is introduced into chamber 10 through apertures 12 so as lto impart a swirling or vortex motion to the gas.
  • the general configuration of the torch permits part of the g-as to liow into and out of the rear electrode 14 and -then all of the gas through the nozzle 16 so long as the ga-s is introduced at a suflicient velocity. That is, if the inlet velocity is greater than 0.25 Mach, then there will be a sufficient pressure drop within the chamber 10 -between its outer wall 60 and the area near the torch axis to force a substantial portion of the gas into ele-ctrode 14. This results in -a longer arc which increases the arc voltage. This pressure drop also aids in maintaining a vortex flow of gas.
  • An appropriate power supply (not shown) is connected to the cup electrode 14 Iand to a workpiece.
  • the workpiece will, of course, vary according to the application for which the torch is being used. For example, it may be .a metal plate that is being scarfed, or it may be the charge of a metal melting furnace. Whatever it may be, the combination of the high voltage arc operating in a transferred manner renders this torch extremely useful for such applications.
  • the arc is initiated by .any .suitable means, such as for example a high-frequency start, capacitor discharge or by inserting a conducting rod into the torch through the nozzle.
  • the quantity of gas is then increased as desired.
  • the arc that is finally established will, because of the flow of gas in the torch, ex-tend from Van area appreciably along the length of the cup electrode, through nozzle 16, to an electrode workpiece.
  • the nozzle be between about 1.2 and 3.0 and preferably about 2.
  • direct current with straight or reverse polarity connection may be used with this device, it is preferred not only from the standpoint of achieving higher power levels at lower costs, but also from the standpoint of longer life for the cup electrode to operate the torch with single phase alternating current.
  • the arc tends to localize over a particular area of the cup-shaped electrode, whereas, with alternating current the arc will run along substantially the entire length of the electrode. More specically, the arc termination will alternate between an area somewhere near the closed end of the cup-shaped electrode and its mouth on every half cycle of the alternating current.
  • a watercooled copper field coil could be placed around the cup electrode so as to produce a magnetic field, thus causing the arc to rotate. Such coil will not only cause the arc to rotate, but it will also spread out the arc on the electrode so as to permit greater overall currents with workable current densities.
  • Electrode materials have been found to be useful with various types of gases.
  • copper, silver, aluminum, zirconium, and molybdenum are useful materials when the device is operated with reactive gases such as air, oxygen, carbon dioxide, and carbon monoxide.
  • reactive gases such as air, oxygen, carbon dioxide, and carbon monoxide.
  • the material is also useful for mixtures of an inert gas with air, oxygen, or carbon monoxide.
  • inert gases such as hydrogen, argon, helium, and nitrogen are being used, tungsten, tungsten containing emissive material such as thoria, and carbon is the preferred electrode material.
  • Suitable materials for the insulator have been found to be phenol-aldehyde condensation resins and nylon. However, materials exhibiting like properties could also be used.
  • the cup electrode had a length of 91/2 in. and an I.D. of 1% in.
  • the nozzle had a length of 2.75 in. and an I.D. of 0.951 in.
  • the workpiece, that is the other electrode consisted of a type 304 stainless steel bar approximately 4 in. wide, 2 ft. long, and 3%: in. thick. Oxygen was supplied to the device at the rate of 1000 c.f.h. so as to cause oxidation of the metal, thus, permitting the defects of the metal to be blown away.
  • a tield coil having a magnetomotive force of 16.5 kilo-ampere turns was placed around the rear electrode, the direction of the field being toward the bottom of the cup electrode.
  • 665 amperes (D.C.) were supplied to the device.
  • the arc voltage was 285 volts.
  • the total power to the torch was 190 k.w. of which approximately 152 kw. went to the gas and to the workpiece yielding an efficiency of approximately 80 percent.
  • the torch was set at an angle of 55 degs., the nozzle being directed opposite the direction of travel of the workpiece.
  • the stando@ distance of the torch from the In these examples, apparatus workpiece was approximately ll/z in.
  • the workpiece had a travel speed of approximately 250 in./min.
  • EXAMPLE 2 Fusion scarfing The dimensions of the torch used in this example were the same as those of Example 1. Likewise, the torch angle and the standoff distance were the same. The travel speed of the workpiece was 50 i.p.m. The workpiece electrode was again a 304 stainless steel bar of approximately the same dimensions. Again a field coil was used, the magnetomotive force this time being 14.3 kiloampere turns, the direction of the r'ield again being toward the bottom of the rear electrode. However, in this example, argon was supplied to the torch at the rate of 2000 c.f.h. so as to melt the metal to remove the surface defects. In this case the metal is not blown away, rather it solidities.
  • the cup electrode had a length of 61A in. and an I.D. of 1/2 in.
  • the nozzle had a constriction having a length of 1/2 in. and an I.D. of M1, in.
  • Oxygen was supplied to the device at the rate of 750 c.f.h.
  • the electrode workpiece was an 8 in. stainless steel plate. With the workpiece acting as the cathode, 300 amperes were supplied to the device.
  • the arc voltage was 650 volts.
  • the total power to the torch was 195 kw. of which approximately 154 kw. went to the gas and to the workpiece yielding a torch eiciency of approximately 79 percent.
  • the torch was directed at the workpiece at an angle of degs. from a standoff distance of 1/2 in.
  • the cup electrode had a length of 10 in. and an LD. of 1% in.
  • the nozzle had a length of 21/2 in. and an I.D. of 1% in.
  • the workpiece electrode consisted of 1500 lbs. of carbon steel scrap. Air was supplied to the torch at a rate of 600 c.f.h. Using single phase alternating current, 1100 amperes were supplied to the torch. The arc voltage was 400 volts. The total power to the device was 440 kw. of which 362 kw. went to the gas and to the workpiece during the initial run yielding an etliciency of approximately 82 percent. As the environment surrounding the torch became hot (1600 degs. C.), the torch etliciency dropped to 40 percent due to inadequate external thermal insulation of the torch.
  • EXAMPLE 5 A Ifernatng current operation in air
  • the cup electrode had a length of 9% in. and an I.D. of 1% in.
  • the nozzle had a length of 2% in. and an I.D. of 1% in.
  • the electrode workpiece was a plate of carbon steel. Air was supplied to the torch at the rate of 500 c.f.h. Using single phase, alternating current 1200 amperes were supplied to the device.
  • the arc voltage was 320 volts.
  • the chamber pressure was approximately 1 atmosphere.
  • the total power to the torch was 375 kw. of which 300 kw. went to the gas and to the workpiece yielding an eiciency of 80 percent.
  • the torch operated for a period of about 10 minutes without any appreciable signs of electrode erosion.
  • Apparatus for producing a high-Voltage high-temperature arc plasma between such apparatus and a metal connected in arc circuit relation therewith which comprises a cup-shaped electrode, a gas-directing nozzle having a L/I.D. of at least about 1.2, said nozzle being in axial alignment with but spaced from said cup-shaped electrode, a chamber surrounding the space between said cup-shaped electrode and nozzle and having means for introducing an arc gas into such chamber to produce a vortical ow in such chamber and said gas-directing nozzle.
  • Apparatus for producing a high-voltage high-temperature arc plasma between such apparatus and a metal connected in arc circuit relation therewith which comprises a cup-shaped electrode, a gas-directing nozzle having a L/I.D. of at least about 1.2, said nozzle being in axial alignment with but spaced from said cup-shaped electrode, a chamber surrounding the space between said cup-shaped electrode and nozzle and being provided with means positioned between the cup electrode and the nozzle for introducing arc gas into such chamber directly into the space between said cup-shaped electrode and nozzle to produce a vortical ow in such chamber and said gas directing nozzle.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Geometry (AREA)
  • Plasma Technology (AREA)
  • Arc Welding In General (AREA)
US223484A 1962-09-13 1962-09-13 High voltage arc plasma generator Expired - Lifetime US3194941A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NL297831D NL297831A (enrdf_load_stackoverflow) 1962-09-13
NL134809D NL134809C (enrdf_load_stackoverflow) 1962-09-13
US223484A US3194941A (en) 1962-09-13 1962-09-13 High voltage arc plasma generator
GB33987/63A GB1007429A (en) 1962-09-13 1963-08-28 Improvements in arc producing apparatus
NO150072A NO115114B (enrdf_load_stackoverflow) 1962-09-13 1963-09-12
DEU4141U DE1916912U (de) 1962-09-13 1963-09-13 Vorrichtung zur erzeugung eines lichtbodenplasmas hoher spannung und hoher temperatur.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US223484A US3194941A (en) 1962-09-13 1962-09-13 High voltage arc plasma generator

Publications (1)

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US3194941A true US3194941A (en) 1965-07-13

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US223484A Expired - Lifetime US3194941A (en) 1962-09-13 1962-09-13 High voltage arc plasma generator

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Country Link
US (1) US3194941A (enrdf_load_stackoverflow)
DE (1) DE1916912U (enrdf_load_stackoverflow)
GB (1) GB1007429A (enrdf_load_stackoverflow)
NL (2) NL297831A (enrdf_load_stackoverflow)
NO (1) NO115114B (enrdf_load_stackoverflow)

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3316082A (en) * 1964-12-08 1967-04-25 Inland Steel Co Oxygen steelmaking
US3368018A (en) * 1965-03-17 1968-02-06 Westinghouse Electric Corp Electrode and electrode tip for use therein
US3394242A (en) * 1963-08-07 1968-07-23 Nat Res Dev Electrical arc control
US3398229A (en) * 1964-10-29 1968-08-20 Westinghouse Electric Corp Nonconsumable arc electrode
US3407281A (en) * 1967-09-20 1968-10-22 Cabot Corp Plasma producing apparatus
US3446902A (en) * 1968-01-08 1969-05-27 Westinghouse Electric Corp Electrode having oxygen jets to enhance performance and arc starting and stabilizing means
US3476861A (en) * 1968-12-17 1969-11-04 Westinghouse Electric Corp Insulating nonconsumable arc electrode
US3480717A (en) * 1968-03-25 1969-11-25 Westinghouse Electric Corp Arc furnace electrode assembly
US3505460A (en) * 1968-05-15 1970-04-07 Westinghouse Electric Corp Electric arc vacuum furnace employing nonconsumable electrode
US3580977A (en) * 1970-02-18 1971-05-25 Westinghouse Electric Corp Quick-change field coil assembly for use in an electrode having a fluid-cooled arcing surface
DE1790209B1 (de) * 1968-09-28 1971-10-14 Siemens Ag Gasstabilisierter lichtbogenbrenner
US3673375A (en) * 1971-07-26 1972-06-27 Technology Applic Services Cor Long arc column plasma generator and method
US3686528A (en) * 1969-12-05 1972-08-22 Tamarack Scient Co Inc Jet pinched plasma arc lamp and method of forming plasma arc
US3818174A (en) * 1972-11-09 1974-06-18 Technology Applic Services Cor Long arc column forming plasma generator
US3958097A (en) * 1974-05-30 1976-05-18 Metco, Inc. Plasma flame-spraying process employing supersonic gaseous streams
US4034250A (en) * 1976-08-16 1977-07-05 Jury Yakovlevich Kiselev Plasmatron
JPS5326757A (en) * 1976-08-26 1978-03-13 Kishenev Poritekunichiesukii I Plasmatron
DE3401777A1 (de) * 1983-01-21 1984-07-26 Plasma Energy Corp., Raleigh, N.C. Plasmagenerator und verfahren zum betreiben desselben
US4559439A (en) * 1983-01-21 1985-12-17 Plasma Energy Corporation Field convertible plasma generator and its method of operation
US4583229A (en) * 1984-01-09 1986-04-15 Aluminum Company Of America Metal melting system
FR2572973A1 (fr) * 1984-11-09 1986-05-16 Plasma Energy Corp Chalumeau a arc de plasma.
US4845334A (en) * 1988-01-26 1989-07-04 Oregon Metallurgical Corporation Plasma furnace inert gas recycling system and process
EP0553758A1 (en) * 1992-01-30 1993-08-04 Retech, Inc. Arc plasma torch having tapered-bore electrode
EP0605010A1 (en) * 1992-12-31 1994-07-06 Osram Sylvania Inc. Vortex arc generator and method of controlling the length of the arc
EP0605011A1 (en) * 1992-12-31 1994-07-06 Osram Sylvania Inc. DC plasma arc generator with erosion control and method of operation
EP0750448A1 (fr) * 1995-06-20 1996-12-27 AEROSPATIALE SOCIETE NATIONALE INDUSTRIELLE, Société Anonyme Dispositif de refroidissement externe d'une torche à plasma
US5880426A (en) * 1996-08-28 1999-03-09 Doryokuro Kakunenryo Kaihatsu Jigyodan Indirectly-cooled plasma jet torch
WO1999056507A1 (en) * 1998-04-27 1999-11-04 Hypertherm, Inc. A nozzle for a plasma arc torch with an exit orifice having an inlet radius and an extended length to diameter ratio
US6221123B1 (en) 1998-01-22 2001-04-24 Donsco Incorporated Process and apparatus for melting metal
CN112798884A (zh) * 2020-12-15 2021-05-14 珠海格力电器股份有限公司 一种便捷燃弧装置、控制方法、电弧发生器及应用

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3118046A (en) * 1961-05-03 1964-01-14 Thermal Dynamics Corp Electric arc torch
US3131288A (en) * 1961-08-07 1964-04-28 Thermal Dynamics Corp Electric arc torch

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3118046A (en) * 1961-05-03 1964-01-14 Thermal Dynamics Corp Electric arc torch
US3131288A (en) * 1961-08-07 1964-04-28 Thermal Dynamics Corp Electric arc torch

Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3394242A (en) * 1963-08-07 1968-07-23 Nat Res Dev Electrical arc control
US3398229A (en) * 1964-10-29 1968-08-20 Westinghouse Electric Corp Nonconsumable arc electrode
US3316082A (en) * 1964-12-08 1967-04-25 Inland Steel Co Oxygen steelmaking
US3368018A (en) * 1965-03-17 1968-02-06 Westinghouse Electric Corp Electrode and electrode tip for use therein
US3407281A (en) * 1967-09-20 1968-10-22 Cabot Corp Plasma producing apparatus
US3446902A (en) * 1968-01-08 1969-05-27 Westinghouse Electric Corp Electrode having oxygen jets to enhance performance and arc starting and stabilizing means
US3480717A (en) * 1968-03-25 1969-11-25 Westinghouse Electric Corp Arc furnace electrode assembly
US3505460A (en) * 1968-05-15 1970-04-07 Westinghouse Electric Corp Electric arc vacuum furnace employing nonconsumable electrode
DE1790209B1 (de) * 1968-09-28 1971-10-14 Siemens Ag Gasstabilisierter lichtbogenbrenner
US3476861A (en) * 1968-12-17 1969-11-04 Westinghouse Electric Corp Insulating nonconsumable arc electrode
US3686528A (en) * 1969-12-05 1972-08-22 Tamarack Scient Co Inc Jet pinched plasma arc lamp and method of forming plasma arc
US3580977A (en) * 1970-02-18 1971-05-25 Westinghouse Electric Corp Quick-change field coil assembly for use in an electrode having a fluid-cooled arcing surface
US3673375A (en) * 1971-07-26 1972-06-27 Technology Applic Services Cor Long arc column plasma generator and method
US3818174A (en) * 1972-11-09 1974-06-18 Technology Applic Services Cor Long arc column forming plasma generator
US3958097A (en) * 1974-05-30 1976-05-18 Metco, Inc. Plasma flame-spraying process employing supersonic gaseous streams
US4034250A (en) * 1976-08-16 1977-07-05 Jury Yakovlevich Kiselev Plasmatron
JPS5326757A (en) * 1976-08-26 1978-03-13 Kishenev Poritekunichiesukii I Plasmatron
DE3401777A1 (de) * 1983-01-21 1984-07-26 Plasma Energy Corp., Raleigh, N.C. Plasmagenerator und verfahren zum betreiben desselben
FR2539942A1 (fr) * 1983-01-21 1984-07-27 Plasma Energy Corp Generateur de plasma et son procede de fonctionnement
US4549065A (en) * 1983-01-21 1985-10-22 Technology Application Services Corporation Plasma generator and method
US4559439A (en) * 1983-01-21 1985-12-17 Plasma Energy Corporation Field convertible plasma generator and its method of operation
US4583229A (en) * 1984-01-09 1986-04-15 Aluminum Company Of America Metal melting system
FR2572973A1 (fr) * 1984-11-09 1986-05-16 Plasma Energy Corp Chalumeau a arc de plasma.
US4845334A (en) * 1988-01-26 1989-07-04 Oregon Metallurgical Corporation Plasma furnace inert gas recycling system and process
EP0553758A1 (en) * 1992-01-30 1993-08-04 Retech, Inc. Arc plasma torch having tapered-bore electrode
EP0605010A1 (en) * 1992-12-31 1994-07-06 Osram Sylvania Inc. Vortex arc generator and method of controlling the length of the arc
EP0605011A1 (en) * 1992-12-31 1994-07-06 Osram Sylvania Inc. DC plasma arc generator with erosion control and method of operation
EP0750448A1 (fr) * 1995-06-20 1996-12-27 AEROSPATIALE SOCIETE NATIONALE INDUSTRIELLE, Société Anonyme Dispositif de refroidissement externe d'une torche à plasma
US5828029A (en) * 1995-06-20 1998-10-27 Aerospatiale Societe Nationale Industrielle Device for externally cooling a plasma torch
US5880426A (en) * 1996-08-28 1999-03-09 Doryokuro Kakunenryo Kaihatsu Jigyodan Indirectly-cooled plasma jet torch
US6221123B1 (en) 1998-01-22 2001-04-24 Donsco Incorporated Process and apparatus for melting metal
WO1999056507A1 (en) * 1998-04-27 1999-11-04 Hypertherm, Inc. A nozzle for a plasma arc torch with an exit orifice having an inlet radius and an extended length to diameter ratio
CN112798884A (zh) * 2020-12-15 2021-05-14 珠海格力电器股份有限公司 一种便捷燃弧装置、控制方法、电弧发生器及应用

Also Published As

Publication number Publication date
NL297831A (enrdf_load_stackoverflow)
GB1007429A (en) 1965-10-13
NO115114B (enrdf_load_stackoverflow) 1968-07-29
DE1916912U (de) 1965-06-03
NL134809C (enrdf_load_stackoverflow)

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