EP1061781A2 - Procédé de réalisation du point de démarrage de l'arc électrique dans l'électrode d'une torche de coupage par plasma, et électrode correspondante - Google Patents

Procédé de réalisation du point de démarrage de l'arc électrique dans l'électrode d'une torche de coupage par plasma, et électrode correspondante Download PDF

Info

Publication number
EP1061781A2
EP1061781A2 EP00110980A EP00110980A EP1061781A2 EP 1061781 A2 EP1061781 A2 EP 1061781A2 EP 00110980 A EP00110980 A EP 00110980A EP 00110980 A EP00110980 A EP 00110980A EP 1061781 A2 EP1061781 A2 EP 1061781A2
Authority
EP
European Patent Office
Prior art keywords
electrode
seat
electric arc
insert
pellet
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.)
Withdrawn
Application number
EP00110980A
Other languages
German (de)
English (en)
Other versions
EP1061781A3 (fr
Inventor
Giorgio Bassi
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.)
Tecmo SRL
Original Assignee
Tecmo SRL
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 Tecmo SRL filed Critical Tecmo SRL
Publication of EP1061781A2 publication Critical patent/EP1061781A2/fr
Publication of EP1061781A3 publication Critical patent/EP1061781A3/fr
Withdrawn legal-status Critical Current

Links

Images

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
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3442—Cathodes with inserted tip

Definitions

  • the present invention relates to a method for providing the electric arc starting point in an electrode of a thermal plasma cutting torch.
  • the invention also relates to an electrode provided by means of the method.
  • Conventional thermal plasma cutting torches work by supplying the excitation and ionization energy to the gas whose plasma is to be generated.
  • the gas is passed through an electric arc formed between a negative electrode or cathode and a part to be cut, which acts as an anode.
  • a sleeve which has an annular nozzle and forms, together with the electrode, a tubular channel connected to the supply of the gas whose plasma is to be produced.
  • the sleeve can temporarily act as an anode in order to generate a pilot arc adapted to facilitate the starting of the main arc between the negative electrode and the part.
  • the main arc extends, through the nozzle, between the negative electrode and the part, while the gas exits from the nozzle in the form of a plasma jet which strikes the part at high temperature and high speed.
  • the starting point of the electric arc is constituted by an insert which is accommodated in a seat formed axially in the electrode.
  • the insert is typically constituted by a cylindrical pellet of hafnium or zirconium which is highly resistant to spark erosion but causes considerable drawbacks due to the current method with which it is currently implanted in the electrode.
  • the pellet is in fact usually implanted by interference fit in a seat of the electrode, with the following negative effects:
  • the aim of the present invention is to provide a new method for providing the starting point of the electric arc, so as to obviate the above listed shortcomings of the prior art.
  • an object of the present invention is to provide an improved electrode according to the new method.
  • a method for providing the starting point of an electric arc in an electrode of a thermal plasma cutting torch characterized in that it comprises the steps of: forming a substantially cylindrical axial seat in the electrode, at the end from which the electric arc must start, said seat being adapted to receive, with tolerance, a substantially cylindrical insert made of hafnium or zirconium, and heading said insert inside said seat so as to produce a stable and uniform intimate contact of its outer surface with the inner surface of said seat which is adapted to firmly retain said insert in said seat.
  • the electrode provided with this method is characterized in that it has, at the end from which the electric arc is to start, a cylindrical insert made of hafnium or zirconium which is headed in an axial seat formed in said end of said electrode so as to be firmly retained in said seat.
  • the reference numeral 1 designates an electrode of a plasma cutting torch.
  • the electrode is associated with the body of the torch and forms, together with an external sleeve which is coaxial thereto, a tubular chamber which is connected to the supply of a gas whose plasma is to be generated.
  • the sleeve and the other parts of the torch are not shown because they are outside the scope of the present invention and are in any case already known in the art, for example from EPA 97120002.7 of November 14, 1997 by this same Applicant.
  • the electrode 1 has an ogive-like tapered end 2 in which a seat or blind hole 3 is formed axially and centrally.
  • the hole 3 is cylindrical and forms a seat for a pellet 4 of erosion-resistant material, for example hafnium or zirconium.
  • the pellet 4 is constituted in practice by an insert whose cylindrical shape is complementary to the shape of the hole, so that it can be inserted therein with a minimal tolerance of preferably 0.05 to 0.10 mm.
  • the hole 3 is slightly shallower than the pellet 4, so that the pellet can be riveted inside the hole by forcing from outside with a striking mass on the end of the pellet that protrudes from the hole 3.
  • the riveting of the pellet 4 causes the pellet to be headed inside the hole, undergoing a radial deformation which causes it to anchor firmly, with all of its surface, to the electrode.
  • the radial deformation undergone by the pellet 4 allows to achieve stable and uniform intimate contact between the inner wall of the hole 3 and the outer wall of the pellet 4.
  • the electrode thus obtained allows to achieve the intended aim and object, i.e., higher thermal and electric conductivity, a saving of material due to the smaller dimensions of the pellet with respect to conventional ones, and provision of a more precise cut.
  • the present invention can be applied to electrodes having any shape without thereby abandoning the scope of the appended claims.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Plasma Technology (AREA)
  • Arc Welding In General (AREA)
EP00110980A 1999-06-14 2000-05-29 Procédé de réalisation du point de démarrage de l'arc électrique dans l'électrode d'une torche de coupage par plasma, et électrode correspondante Withdrawn EP1061781A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT1999BO000319A IT1309290B1 (it) 1999-06-14 1999-06-14 Procedimento per la realizzazione del punto di scocco dell'arcovoltaico nell'elettrodo di una torcia per taglio a plasma ed
ITBO990319 1999-06-14

Publications (2)

Publication Number Publication Date
EP1061781A2 true EP1061781A2 (fr) 2000-12-20
EP1061781A3 EP1061781A3 (fr) 2002-10-16

Family

ID=11344048

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00110980A Withdrawn EP1061781A3 (fr) 1999-06-14 2000-05-29 Procédé de réalisation du point de démarrage de l'arc électrique dans l'électrode d'une torche de coupage par plasma, et électrode correspondante

Country Status (2)

Country Link
EP (1) EP1061781A3 (fr)
IT (1) IT1309290B1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1260021A (en) * 1969-10-27 1972-01-12 British Titan Ltd Heating device
US4055741A (en) * 1975-12-08 1977-10-25 David Grigorievich Bykhovsky Plasma arc torch
EP0437915A2 (fr) * 1990-01-17 1991-07-24 ESAB Welding Products, Inc. Electrode pour torche à plasma à arc
WO1996004771A1 (fr) * 1994-07-29 1996-02-15 Hypertherm, Inc. Electrode pour un chalumeau a arc de plasma
EP0787556A1 (fr) * 1996-02-02 1997-08-06 Thermal Dynamics Corporation Electrode d'une torche à plasma

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1260021A (en) * 1969-10-27 1972-01-12 British Titan Ltd Heating device
US4055741A (en) * 1975-12-08 1977-10-25 David Grigorievich Bykhovsky Plasma arc torch
EP0437915A2 (fr) * 1990-01-17 1991-07-24 ESAB Welding Products, Inc. Electrode pour torche à plasma à arc
WO1996004771A1 (fr) * 1994-07-29 1996-02-15 Hypertherm, Inc. Electrode pour un chalumeau a arc de plasma
EP0787556A1 (fr) * 1996-02-02 1997-08-06 Thermal Dynamics Corporation Electrode d'une torche à plasma

Also Published As

Publication number Publication date
IT1309290B1 (it) 2002-01-22
ITBO990319A0 (it) 1999-06-14
EP1061781A3 (fr) 2002-10-16
ITBO990319A1 (it) 2000-12-14

Similar Documents

Publication Publication Date Title
RU2659803C2 (ru) Способ и устройство повышения эксплуатационного ресурса плазменно-дуговой горелки
KR100344932B1 (ko) 플라즈마 아크 토치용 전극 및 그 제조 방법
US5464962A (en) Electrode for a plasma arc torch
US10863610B2 (en) Plasma torch and components thereof
JP3708063B2 (ja) プラズマアークトーチ用電極の半製品
US11310901B2 (en) Plasma torch and components thereof
RU2674361C2 (ru) Устройство электрода для плазменных резаков
CA2303546C (fr) Electrode a bout conique pour chalumeaux de decoupage par jet de plasma
EP2716975B1 (fr) Bougie de préchauffage et procédé pour fabriquer une bougie de préchauffage
JP3198727U (ja) プラズマ切断トーチ用電極
EP1061781A2 (fr) Procédé de réalisation du point de démarrage de l'arc électrique dans l'électrode d'une torche de coupage par plasma, et électrode correspondante
CN209990600U (zh) 永磁霍尔推力器点火装置
CN115681053A (zh) 一种自维持霍尔推力系统的运行方法
US11482395B2 (en) Heaterless hollow cathode
US20240014014A1 (en) High current heaterless hollow cathode
RU2209483C2 (ru) Электронно-ионный источник
AU763778B2 (en) Tapered electrode for plasma arc cutting torches
JPS63248539A (ja) プラズマト−チの製造方法
JPS60157148A (ja) 電子発生装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20030326