US3735592A - Apparatus for protection of a gas jet generator - Google Patents

Apparatus for protection of a gas jet generator Download PDF

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Publication number
US3735592A
US3735592A US00085118A US3735592DA US3735592A US 3735592 A US3735592 A US 3735592A US 00085118 A US00085118 A US 00085118A US 3735592D A US3735592D A US 3735592DA US 3735592 A US3735592 A US 3735592A
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United States
Prior art keywords
arc
electrodes
gas jet
change
electrode
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
US00085118A
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English (en)
Inventor
G Schafer
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Siemens AG
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Siemens AG
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Filing date
Publication date
Priority claimed from DE19691955147 external-priority patent/DE1955147C/de
Application filed by Siemens AG filed Critical Siemens AG
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Publication of US3735592A publication Critical patent/US3735592A/en
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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
    • 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
    • H05H1/3484—Convergent-divergent 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
    • H05H1/3494—Means for controlling discharge parameters
    • 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
    • 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
    • H05H1/40—Details, e.g. electrodes, nozzles using applied magnetic fields, e.g. for focusing or rotating the arc

Definitions

  • a gas jet generating apparatus has a container with an electric arc chamber from which the gas jet is to issue, two arc electrodes are provided in the chamber, and at least one of the electrodes has a metallic portion defining a foot-point locality for the arc.
  • the combination of a protective device has near at least one of the electrodes, at vaporizable means of material different from that of said electrode portion so as to effect, when burning off, a change in spectral distribution of the gas jet.
  • a signal generating arrangement that is responsive to the spectral distribution for deriving a signal from the change.
  • a plasma burner with an arc chamber is known from German published patent application 1,271,852.
  • a cup electrode is provided which extends into the chamber of this plasma burner.
  • the arc burns from this cup electrode into a hollow cylinder electrode under a tangential directed gas supply.
  • the arc chamher there is formed a flow cylinder and, in the cup electrode, there is formed a double flow with an axial component.
  • the arc is gas vaporized.
  • one of the two electrodes, preferably the cup electrode is arranged so as to be adjustable in axial di rection.
  • the electrodes are made of copper and are provided with a liquid cooling arrangement, preferably a water cooling system.
  • a liquid cooling arrangement preferably a water cooling system.
  • Magnetic coils arranged axially and about the respective electrodes serve to rotate the arc.
  • the coolant then passes through the intermediate space between the electrode jacket and the magnetic coil and also protects the electrical insulation of the coils from the high temperature of the arc.
  • the arc slowly burns off the copper of the electrode jacket at the foot-point locality.
  • the cooling water can exit through the opening of the defective electrode jacket.
  • the steam is then transported with the gas jet out of the exit nozzle of the burning chamber and so contaminates the exiting 'gas jet.
  • the water vaporizes from the heat of the arc in the cooling channel. Because of the gas pressure, the cooling water is moved from the burnt-through location, so that other parts, especially the magnetic coils, can become damaged.
  • the energy supply of the apparatus must be dis connected as soon as possible before a burn-through of an electrode. I
  • I provide the electrode at least in the region near the foot-point locality of the arc with a means that, when burned, changes'the spectral distribution of the gas jet. From this deviating spectral distribution, a signal for disconnecting the current supply of the arc is derived.
  • Suitable for this purpose are for example aluminum and chrome.
  • the jacket can be made for example from aluminum or an aluminum alloy especially Dural.
  • non-metallic materials can also be used, for example, sodium salt or a material containing sodium. This material can be disposed between the parts of a double-walled electrode.
  • the material vaporized at the foot-point locality causes a characteristic discoloration of the exiting gas jet.
  • An optical interference filter having a pass region optimized for the wavelengths of the emission lines to be measured is provided. By means of this interference filter, this wavelength range is filtered out and directed to a photoelectronic component as an optical signal.
  • the signal which is in turn provided by this component, is supplied via an amplifier to the electric power supply means of the gas jet apparatus; this signal can for example act upon the blocking grid (gate) of the thyristors of an electronic alternating or polyphase current control for controlling the power. Or, the signal can be used to open the breaker of the apparatus.
  • photoresistors that are connected together in the form of a wheatstone bridge.
  • the change in the bridge current serves as a signal for disconnecting the apparatus.
  • the filtered radiation can be directed to active photoelements whose sensitivity for the wavelengths of the radiation directed to these elements is sufficient for generating a photo current that can be used for disconnecting the current supply.
  • FIG. 1 illustrates an apparatus for the protection of the gas jet generator according to the invention
  • FIG. 2 illustrates an electrode of the arc chamber of FIG. 1 equipped with an intermediate coating of material having a color spectrum with pronounced emission lines at wavelengths different from the emission-line wavelengths of the electrode material proper.
  • cylinder electrode 2 and a cup electrode 4 are respectively connected to the output of a rectifier 6 equipped with uncontrolled electronic valves (diodes) 8.
  • the diodes 8 being ratedfor a current of approximately 850 amperes at a directcurrent voltage of 700 volts.
  • an electronic polyphase current controller 10 having electric valves such as thyristors 12.
  • the controller 10 is con nected to a three phase line having an alternating voltage of, for example, 380 volts via a main switch 14.
  • the thyristors 12 of the controller 10 are connected to an ignition grid control device 15 having an electronic grid blocking stage 16.
  • the control device 15 serves to ignition control the thyristors 12.
  • the control device 15 can, for example, receive its signal for displacing the ignition pulses from a regulating apparatus with a current regulator 17 of which one input is specified by-a current pilot (actual-current) magnitude from a current transformer 18 and of which the second input 19 is specified by a current datum magnitude.
  • a current regulator 17 of which one input is specified by-a current pilot (actual-current) magnitude from a current transformer 18 and of which the second input 19 is specified by a current datum magnitude.
  • the electrodes 2 and 4 are arranged in arc chamber 20.
  • one of the electrodes for example the cup electrode .4, is movable in axial direction, this direction being the direction of the gas jet 24 formed in the chamber and exiting through an exit nozzle 22 illustrated in FIG. 1 as a Laval nozzle.
  • Coaxial to the two electrodes 2 and 4 are arranged respective field coils 28 and 29.
  • the coils contain hollow conductors through which flow a cooling liquid.
  • I-Iollow conductors 30 are surrounded by an insulating layer 31.
  • the hollow conductors 30 can be imbedded in an insulating layer 31 of casting resin.
  • the electrodes are provided with liquid cooling as represented in the drawing by the arrows.
  • the coolant such as water, flows through the space between the field coils and the electrodes, the latter being for example made of copper.
  • the electrodes 2 and 4 are provided with respective linings 33 and 34 made of aluminum or a material containing aluminum preferably Dural.
  • the lining is on the electrodes on the side thereof away from the surface of the electrode upon which the arcs impinge.
  • the aluminum vaporizes at the damaged location and changes the color of the exiting gas jet 24.
  • the aluminum has pronounced emission lines at wavelengths of 0.394 microns and 0.961 microns, whereas the copper, in an adequate range above and below these wavelengths, exhibits no pronounced emission line. These emission lines are directed via a filter 38, a collection lens 40 having a diameter determining to the light intensity, and a diaphragm 42 to a photosensitive electronic component.
  • the pass region of the interference filter 38 is restricted to the wavelengths of the emission lines of the aluminum to be measured. Consequently, the photoelement 44 receives radiation as soon as the exiting gas jet 24 transports vaporized aluminum of the linings 33 or 34 through the exit nozzle 22.
  • One terminal of the photoelement 44 is connected to ground or zero potential.
  • a signal is formed in response to the emission lines of the vaporized aluminum and is directed via an amplifier 46 of the grid blocking stage 16.
  • the power supplied to the arcing chamber is thereby disconnected before the arc cuts through the aluminum coating 33 or 34. Should the latter occur, water vapor could exit through the opening cut by the are.
  • the field coil 28 and/or 29 could be damaged.
  • a silicon photocell could be used for the photoelement 44 having a sensitivity region covering the wavelength of 0.394 microns.
  • a solar cell is suitable for the mentioned wavelength.
  • the sensitivity of such a cell is optimized such that the photo-current becomes a maximum when irradiated with a light having a spectral distribution corresponding to that of sun light outside of the atmosphere. These cells still have a good sensitivity at a wave length of 0.39 microns.
  • a gallium-arsenide luminescent diode connected as a radiation detector.
  • the protection arrangement an aluminum layer or coating of the electrodes in the region at which the arc impinges thereupon.
  • the entire surface of the electrode material facing away from the location at which the arc impinges can be welded or soldered to the electrode material or it may be shrunk or cast thereupon.
  • the electrode material can be copper for example.
  • the surfaceof the electrode facing away from the arc can be provided with a covering containing sodium.
  • the electrode material can comprise two like material layers between which is an intermediate layer 50 containing sodium. In this way a coloring of the gas jet is obtained as soon as the first electrode layer burns through.
  • a material containing sodium is provided on the electrode surface facing away from the arc, there must be provided the condition that the sodium does not come into contact with the cooling water.
  • an optacal interference filter can be used which has a pass range corresponding to a limited wavelength range of the gas-jet spectrum.
  • the filter is placed between the gas jet and a photosensitive electronic component that is responsive to a spectral change outside the limited range.
  • Circuit means are connected to the component for disconnecting the power from the electrodes in the arc chamber in response to the spectral change.
  • gas jet generating apparatus having a container with an electric arc chamber from which the gas jet is to issue, two are electrodes in said chamber, at least one of said electrodes having a metallic portion defining a foot point locality for the arc, the combination of a protective device comprising vaporizable means disposed adjacent the metallic portion of at least one of said electrodes for giving off a vapor when burned by the arc, said vaporizable means being made of material different from that of said metallic portion so as to effect, when burning off, a change in spectral distribution of the gas jet, and signal generating means responsive to said spectral distribution for deriving a signal from said change.
  • Gas jet generating apparatus comprising a container with an electric arc chamber from which the gas jet is to issue, two are electrodes in said chamber, arcenergizing current supply said connected to said electrodes and having control means for making and breaking the arc current, said electrodes defining respective foot-point areas for said arc, structural means disposed adjacent at least one of said areas for giving off a vapor when burned by the are, said structural means being made of a material different from that of the electrode proper so as to effect, when burning off, a change in spectral distribution of the gas jet and signal generating means responsive to said spectral distribution and electrically connected to said arc-current control means for breaking said current in response to arc-current spectral change.
  • said vaporizable means of said protective deice device a covering on the electrode surface facing away from the are locality, said covering consisting of said material and having a color spectrum with pronounced emission lines at wavelengths different from the emission-line wavelengths of the electrode material proper.
  • said vaporizable means of material being formed of layers extending over at least a portion of the electrode surface of said respective two arc electrodes which surface faces away from the arc locality, said layers making each of said electrodes a double-walled structure at said portion of said electrode surface, said material having a color spectrum with pronounced emission lines at wavelengths different from the emissiondine wavelengths of the electrode material proper.
  • said combination comprising layers extending over at least a portion of the electrode surface of said respective two are electrodes, which surface faces away from the arc locality, said layers making each of said electrodes a doublewalled structure at said portion of said electrode surface, a coating disposed intermediate said electrodes and said layers, said material having a color spectrum with pronounced emission-lines at wavelengths different from the emission-line wavelengths of the electrode material proper.
  • said apparatus including power supply means connected to said are electrodes, and said signal generating means comprising a photosensitive electronic component for providinga signal change in response to changes in light intensity, an optical interference filter disposed in the path of the light of said gas jet and adapted to pass the emission lines of said light corresponding to the wavelengths of said material to said component, whereby said signal change is provided in response to a change in the intensity of said emission lines, and circuit means connected to said component for disconnecting said power supply means from said electrode in response to said signal change.
  • said circuit means comprising a controller connected to said power supply means for controlling the power supplied to said electrodes, said controller including a grid blocking stage, and electric valves connected to said stage for controllingthe flow of said power to said electrodes, said grid blocking stage being connected to said component, whereby said grid blocking stage actuates said valves for interrupting the flow of said power to said electrodes in response to said signal change.
  • said apparatus including power supply means connected to said arc electrodes, and said signal generating means comprising a photosensitive electronic component, an optical interference filter disposed between said gas jet and said component, said filter having a pass band range corresponding to a limited wavelength range of the gasjet spectrum, and said component being responsive to a spectral change outside said range, and circuit means connected to said component for disconnecting said power supply means from said electrodes in response to said change.
  • said circuit means comprising a controller connected to said power supply means for controlling the power supplied to said electrodes, said controller including a grid blocking stage, and electric valves connected to said stage for controlling the flow of said power to said electrodes, said grid blocking stage being connected to said component, whereby said grid blocking stage actuates said valves for interrupting the flow of said power to said electrodes in response to said signal change.
  • Gas jet generating apparatus comprising a container with an electric arc chamber from which the gas jet is to issue, two are electrodes in said chamber, magnetic field coil means surrounding said electrodes for rotating the arc, arc-energizing current supply means connected to said electrodes and having control means for making and breaking the arc current, said electrodes defining respective foot-point areas for the arc, vaporizable means disposed adjacent at least one of said areas for giving off a vapor when burned by the are after the arc penetrates the electrode, said vaporizable means being made of a material different from that of the electrode proper so as to effect, when burning off, a change in spectral distribution of the gas jet and signal generating means responsive to said spectral distribution and electrically connected to said arc-current control means for breaking said current in response to said spectral change, thereby extinguishing the arc before the arc causes damage to said coil means.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Plasma Technology (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
  • Air Bags (AREA)
US00085118A 1969-11-03 1970-10-29 Apparatus for protection of a gas jet generator Expired - Lifetime US3735592A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691955147 DE1955147C (de) 1969-11-03 Anordnung zum Schutz einer Ein richtung zur Erzeugung eines Gasstrahls

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US3735592A true US3735592A (en) 1973-05-29

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US00085118A Expired - Lifetime US3735592A (en) 1969-11-03 1970-10-29 Apparatus for protection of a gas jet generator

Country Status (10)

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US (1) US3735592A (fr)
AT (1) AT301710B (fr)
AU (1) AU2172570A (fr)
BE (1) BE758297A (fr)
CH (1) CH519289A (fr)
ES (1) ES385129A1 (fr)
FR (1) FR2068387A5 (fr)
GB (1) GB1283909A (fr)
NL (1) NL7014978A (fr)
SE (1) SE353641B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070055656A1 (en) * 2005-08-01 2007-03-08 Semscript Ltd. Knowledge repository
US20170150556A1 (en) * 2014-07-15 2017-05-25 Primetals Technologies Germany Gmbh Electric arc furnace comprising a safety device, and a method for protecting peripheral devices on electric arc furnaces
CN109714850A (zh) * 2018-12-19 2019-05-03 西安航天动力研究所 一种用于产生洁净高温空气的高效方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE461761B (sv) * 1988-05-03 1990-03-19 Fiz Tekh Inst Ioffe Elektrisk ljusbaaganordning

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2797336A (en) * 1954-07-28 1957-06-25 Gen Electric Photoelectric flame detector
US2981062A (en) * 1957-05-21 1961-04-25 Arnoux Corp Method and apparatus for safe operation of engines
US3038306A (en) * 1959-11-24 1962-06-12 Gen Electric Gas turbine overspeed protection system
US3041824A (en) * 1956-05-01 1962-07-03 Amalgamated Growth Ind Inc Propulsion system
US3308623A (en) * 1963-08-19 1967-03-14 Snecma Electro-thermic ejectors
US3359734A (en) * 1964-11-19 1967-12-26 Snecma Electrothermal propulsion unit of the electric arc type
US3504490A (en) * 1968-02-20 1970-04-07 Conductron Corp Light sensitive apparatus for preventing flameout in combustion engines
DE1271852B (de) * 1966-11-05 1975-07-31 Siemens Aktiengesellschaft, 1000 Berlin und 8000 München, 8520 Erlangen Plasmabrenner

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2797336A (en) * 1954-07-28 1957-06-25 Gen Electric Photoelectric flame detector
US3041824A (en) * 1956-05-01 1962-07-03 Amalgamated Growth Ind Inc Propulsion system
US2981062A (en) * 1957-05-21 1961-04-25 Arnoux Corp Method and apparatus for safe operation of engines
US3038306A (en) * 1959-11-24 1962-06-12 Gen Electric Gas turbine overspeed protection system
US3308623A (en) * 1963-08-19 1967-03-14 Snecma Electro-thermic ejectors
US3359734A (en) * 1964-11-19 1967-12-26 Snecma Electrothermal propulsion unit of the electric arc type
DE1271852B (de) * 1966-11-05 1975-07-31 Siemens Aktiengesellschaft, 1000 Berlin und 8000 München, 8520 Erlangen Plasmabrenner
US3504490A (en) * 1968-02-20 1970-04-07 Conductron Corp Light sensitive apparatus for preventing flameout in combustion engines

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070055656A1 (en) * 2005-08-01 2007-03-08 Semscript Ltd. Knowledge repository
US20170150556A1 (en) * 2014-07-15 2017-05-25 Primetals Technologies Germany Gmbh Electric arc furnace comprising a safety device, and a method for protecting peripheral devices on electric arc furnaces
CN109714850A (zh) * 2018-12-19 2019-05-03 西安航天动力研究所 一种用于产生洁净高温空气的高效方法

Also Published As

Publication number Publication date
FR2068387A5 (fr) 1971-08-20
DE1955147A1 (de) 1971-05-13
AU2172570A (en) 1972-05-04
NL7014978A (fr) 1971-05-05
BE758297A (fr) 1971-04-01
SE353641B (fr) 1973-02-05
AT301710B (de) 1972-09-11
CH519289A (de) 1972-02-15
ES385129A1 (es) 1973-04-01
DE1955147B2 (de) 1973-01-25
GB1283909A (en) 1972-08-02

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