US3489876A - Apparatus for mixing working gas and additional gas in arc plasma torches with a very high emission velocity of the plasma stream - Google Patents

Apparatus for mixing working gas and additional gas in arc plasma torches with a very high emission velocity of the plasma stream Download PDF

Info

Publication number
US3489876A
US3489876A US601950A US3489876DA US3489876A US 3489876 A US3489876 A US 3489876A US 601950 A US601950 A US 601950A US 3489876D A US3489876D A US 3489876DA US 3489876 A US3489876 A US 3489876A
Authority
US
United States
Prior art keywords
gas
plasma
mixing
pressure
nozzle
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
US601950A
Other languages
English (en)
Inventor
Lothar Haase
Rudolf Pochert
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.)
Kjellberg Elektroden and Maschinen GmbH Finsterwalde
Original Assignee
Kjellberg Elektroden and Maschinen GmbH
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 Kjellberg Elektroden and Maschinen GmbH filed Critical Kjellberg Elektroden and Maschinen GmbH
Application granted granted Critical
Publication of US3489876A publication Critical patent/US3489876A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H05H1/3421—Transferred arc or pilot arc mode

Definitions

  • An apparatus for mixing the working gas and additional gas in arc plasn'la torches with high emission velocity of the plasma stream into a gas discharge chamber comprising a main housing, two longitudinal hd'psing members in the main housing, a gas connection connected to each of the housing members, first and second valve tappets received in each of the housing members, respectively, and a first and second magnet valve disposed in each of the housing members, respectively, cooperating with the first and second valve tappet, respectively, and having a first and second orifice, respectively," leading into a. first and second lower chamber, respectively.
  • a nozzle is provided in one of the lower chambers communicating therewith, and forms an annular slot about its outer periphery, the other of the lower chambers communicating through the annular slot.
  • a cathode is fixed at one end of the main housing, the lower portion ofthe cathode being surrounded by gases fed from at least one of the lower chambers, and a cutting nozzle is; disposed at .the lower end of the main housing and cooperates with the lower portion of the cathode.
  • the present invention relates to an apparatus for mixing the working gas and additional gas in arc plasma torches with a very high emission velocity of the plasma stream.
  • Arc plasma torches are known and operate in accord ance with the principle of an ionized gas arc, with which high temperatures for the working of working material, mostly for fusion cutting of work pieces; are obtained.
  • the so-called working gas which comprises, for instance, argon or nitrogen
  • the working gas which comprises, for instance, argon or nitrogen
  • This method of operation has a low efiiciency and is, in addition, applicable only up to a low electrical output, since these gases maintain the electrical resistance of the are low and poorly convey the heat.
  • the gas is heated so much in the gas discharge chamber, that the outer cooling gas jacket, which is supposed to protect the cutting nozzle, is penetrated and arcingover occurs between the cutting nozzle and the work piece.
  • an additional gas is applied to the arc, in addition to the working gas, for instance, hydrogen and in particular only upon starting the main arc, which increases the electrical resistance of the arc and conveys the heat better.
  • the timing of the appearance of this additional gas in the gas discharge chamber is very important for the safe operation of the plasma burner, for which reason advantageously magnet valves are applied for the control of the additional gas, which magnet valves are arranged as close as possible to the gas discharge chamber. If this timing is too soon, the pilot are required for the starting 3,489,875 Patented Jan. 13, 1970 of the main arc and ignited before with the working gas, is extinguished. If the timing is too late, one obtains at first the operation without additional gas, whereby the cutting nozzle is damaged or destroyed by overarcing.
  • the efficiency is improved by exploitation of the recombination heat and the output density is increased in the plasma ray.
  • the diameter of the bore of the cutting nozzle By reducing the diameter of the bore of the cutting nozzle, one obtains an additional increase of the output density and of the exit velocity of the plasma ray.
  • Plasma burners with very high exit velocity of the plasma ray require, as it is known, a high operational pressure of the operation gases, in order to obtain the gas quantity required for the transportation of a large energy. Since the plasma operates in the direction of narrowing the nozzle, different gas-through puts are obtained in case of different electrical outputs, which gas through-puts contrary'to the desired through-put of the gas, are in reversed order proportional to the output. Furthermore, during ignition of theplasma, the pressure in the discharge chamber increases. This leads to the drawback that also the mixing ratio, in particular in case of gases with very different specific weights, is changed so much, that the operation cannot be maintained.
  • the pressure orifices are disposed advantageously between the mixing nozzle and the magnet valves for all working gas an the additional gas.
  • the technically economical effects, particularly the technical progress of the present invention resides in the fact that, by the appreciably higher pressure in front of the pressure orifices than the pressure in the gas discharge chamber, the mixing ratio remains nearly constant by the pressure variation in the gas discharge chamber caused by a change of the electrical output, while the gas throughput sets itself in accordance with the difference between the pressures in front and behind the pressure orifices.
  • the apparatus comprises connections 8 and 9 for the working gas and the additional gas, respectively, which gases are operational gases available at high pressure.
  • a magnet valve 4 is'disclosed in open position and a magnet valve 5 is shown in closed position.
  • the working gases flow through bores 21 and 22 of the valve tappet 23, and through the pressure orifice 1, the additional gas through the bores 24 and 25 of the valve tappet 26 and through the pressure orifice 2 to the mixing nozzle 3.
  • the pressure orifices 1 and 2 are inserted in the housing 19 and 20 of the magnet valves 4.; and
  • the mixing nozzle 3 comprises two concentrically disposed nozzles 15 and 16.
  • the outer nozzle 16 forms an annular slot about the inner nozzle 15.
  • the working gas flows through the nozzle 15 and sucks thereby the specific lighter additional gas through the nozzle 16 from the gas conduit 17 in the mixing bore or conduit 18 where both gases admix.
  • the gas mixture surrounds the cathode carrier l1 and enters into the gas discharge chamber 6 and emerges from the cutting nozzle 7.
  • the cathode is, as it is known, clamped in the cathode carrier 11, which is insulated by the insulator 12 relative to the main housing 13.
  • a pilot are burning between the cathode 10 and the cutting nozzle '7, which pilot is driven out from the cutting nozzle 7 by the carrier gases heated by the pilot arc in the gas discharge chamber, operates as a narrowing of the cutting nozzle 7, whereby the pressure in the gas discharge chamber increases.
  • the main arc which burns between the cathode 10 and the work piece, 14, is in operation.
  • Variations of the electrical output of the main arc cause accordingly likewise pressure variations in the gas discharge chamber 6.
  • the gas pressures in front of the pressure orifices 1 and 2 are still appreciably higher than the pressures in the gas discharge chamber 6. For this reason, pressure variations in the gas discharge chamber affect only slightly the gas throughput, which adjusts itself correspondingly to the pressures prevailing in front of and behind the pressure orifices 1 and 2.
  • the mixing ratio between working gas and additional gas remains thus approximately constant.
  • the pressures in front of the orifices 1 and 2 are chosen advantageously so high, for instance atmospheres above atmospheric pressure, such that there occurs on the one hand, a least possible variation of the gas throughput and a perfect ignition and operation of the plasma burner, and, on the other hand, also still an economical exploitation of the gas bottles of the carrier gases is obtained.
  • the diameter of the pressure orifices 1 and 2 follows in accordance with the desired mixing ratio and the specific weight of the carrier gases, whereby the pressures in front of the pressure orifices 1 and 2 are equal as much as possible for both carrier gases.
  • the adjusted gas pressures do not need any change or variation, even upon application of nozzles 7 with different diameters, since the mixing ratio and the gas throughout are determined by the pressure orifices 1 and 2.
  • the present invention consists not only merely in the execution of a pressure drop, but in the arrangement and application, respectively, of this pressure drop in plasma burners.
  • the discharge chamber is understood the space between the nozzle and the cathode.
  • the discharge burns mainly in the cone 6. It is also in certain measure in the cylindrical part about the cathode carrier and spreads out in a direction towards the mixing nozzle 3.
  • the known plasma burners and generally also welding burners with mixed working gases work with the principle of the injector mixing nozzle.
  • an adjustable pressure drop is produced over pressure step orifices in front of the mixing nozzle, as well as in th o dui of th add t on l gas a d l o i t e o g gas conduit.
  • the unique adjustable mixing ratio of both gases remains constant independent of the pressureand output-ratio in the discharge chamber. This constant ratio is obtained by the arrangement of the pressure orifices and the mixing noz- Zle.
  • An apparatus for mixing the working gas and additional gas in arc plasma torches with high emission ve locity of the plasma stream into a gas discharge chamber comprising a main housing,
  • first and second magnet valve disposed in each of said housing members, respectively, to cooperate with said first and second valve tappet, respectively
  • said first and second magnet valve cooperating with saidfirst and second orifice, respectively, to pass gases through said first and second orifice
  • said nozzle defining an annular slot about its outer periphery
  • a cathode holder received in said main housing and retaining said cathode in a predetermined position, the lower portion of said cathode being surrounded by gases fed from said one of said lower chambers, and
  • a cutting nozzle disposed at the lower end of said main housing and cooperating with said lower portion of said cathode.
  • said mixing conduit communicating with said lower portion of said cathode for feeding gases thereto.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Plasma Technology (AREA)
US601950A 1966-04-22 1966-12-15 Apparatus for mixing working gas and additional gas in arc plasma torches with a very high emission velocity of the plasma stream Expired - Lifetime US3489876A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19661564229 DE1564229A1 (de) 1966-04-22 1966-04-22 Verfahren zur Mischung des Arbeitsgases und des Zusatzgases in Lichtbogen-Plasmabrennern mit sehr hoher Austrittsgeschwindigkeit des Plasmastrahles und Anordnung zur Durchfuehrung des Verfahrens
DEK0059068 1966-04-22

Publications (1)

Publication Number Publication Date
US3489876A true US3489876A (en) 1970-01-13

Family

ID=25753053

Family Applications (1)

Application Number Title Priority Date Filing Date
US601950A Expired - Lifetime US3489876A (en) 1966-04-22 1966-12-15 Apparatus for mixing working gas and additional gas in arc plasma torches with a very high emission velocity of the plasma stream

Country Status (3)

Country Link
US (1) US3489876A (xx)
DE (1) DE1564229A1 (xx)
NL (1) NL6609360A (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4445021A (en) * 1981-08-14 1984-04-24 Metco, Inc. Heavy duty plasma spray gun
US5624586A (en) * 1995-01-04 1997-04-29 Hypertherm, Inc. Alignment device and method for a plasma arc torch system
WO2014209974A1 (en) * 2013-06-24 2014-12-31 Thermal Dynamics Corporation Gas control system for a plasma arc torch

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2960594A (en) * 1958-06-30 1960-11-15 Plasma Flame Corp Plasma flame generator
US3089944A (en) * 1962-01-19 1963-05-14 Air Reduction Arc welding

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2960594A (en) * 1958-06-30 1960-11-15 Plasma Flame Corp Plasma flame generator
US3089944A (en) * 1962-01-19 1963-05-14 Air Reduction Arc welding

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4445021A (en) * 1981-08-14 1984-04-24 Metco, Inc. Heavy duty plasma spray gun
US5624586A (en) * 1995-01-04 1997-04-29 Hypertherm, Inc. Alignment device and method for a plasma arc torch system
WO2014209974A1 (en) * 2013-06-24 2014-12-31 Thermal Dynamics Corporation Gas control system for a plasma arc torch
US9510435B2 (en) 2013-06-24 2016-11-29 Victor Equipment Company Gas control system for a plasma ARC torch

Also Published As

Publication number Publication date
DE1564229A1 (de) 1970-04-09
NL6609360A (xx) 1968-01-08

Similar Documents

Publication Publication Date Title
US3004137A (en) Method and apparatus for the production of high gas temperatures
US4674683A (en) Plasma flame spray gun method and apparatus with adjustable ratio of radial and tangential plasma gas flow
US3730668A (en) Combustion method of gas burners for suppressing the formation of nitrogen oxides and burner apparatus for practicing said method
US2960594A (en) Plasma flame generator
US4656330A (en) Plasma jet torch having converging anode and gas vortex in its nozzle for arc constriction
US4860533A (en) Torch igniter for a combustor having U.V. flame detection
US3122212A (en) Method and apparatus for the drilling of rock
US4342551A (en) Ignition method and system for internal burner type ultra-high velocity flame jet apparatus
JP2009162478A (ja) 予混合予旋回式プラズマ支援パイロット装置
US3075065A (en) Hyperthermal tunnel apparatus and electrical plasma-jet torch incorporated therein
CA2081458A1 (en) Process and apparatus for reducing electrode wear in a plasma arc torch
US3360682A (en) Apparatus and method for generating high-enthalpy plasma under high-pressure conditions
US3147795A (en) Burner utilizing an eddy plate for proper mixing of fuel and air
JPH10505706A (ja) 高速、高圧プラズマ銃
US3114826A (en) High-temperature spray apparatus
US3246115A (en) Arc compounded combustion and flame arrangement
JPH05505697A (ja) アークトーチ用ガス冷却カソード
US3635644A (en) Infrared burner and method of increasing the heat flux radiated therefrom
US2880792A (en) Flame igniter
JPH01155105A (ja) 微粉燃料バーナ
US3849058A (en) Gas burner for coke oven exhaust gas
US3255803A (en) Torch with igniter
US3489876A (en) Apparatus for mixing working gas and additional gas in arc plasma torches with a very high emission velocity of the plasma stream
WO1992020913A1 (en) Plasma ignition apparatus and method for enhanced combustion and flameholding in engine combustion chambers
NZ502595A (en) Gas burner with high turn-down ratio