US3520978A - Control circuit for automatic positioning of pairs of electrodes in smelting furnaces - Google Patents

Control circuit for automatic positioning of pairs of electrodes in smelting furnaces Download PDF

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Publication number
US3520978A
US3520978A US796769A US3520978DA US3520978A US 3520978 A US3520978 A US 3520978A US 796769 A US796769 A US 796769A US 3520978D A US3520978D A US 3520978DA US 3520978 A US3520978 A US 3520978A
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Prior art keywords
electrodes
electrode
furnace
current
contact
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Expired - Lifetime
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US796769A
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English (en)
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Eivind Christian Krog Svendsen
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Elektrokemisk AS
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Elektrokemisk AS
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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
    • H05B7/144—Power supplies specially adapted for heating by electric discharge; Automatic control of power, e.g. by positioning of electrodes
    • H05B7/148—Automatic control of power
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/10—Nuclear fusion reactors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • the present invention relates to controls for automatically positioning pairs of electrodes which are seriesconnected to either several single-phase transformers or to one multi-phase transformer. Specifically, pairs of electrodes are series-connected within each single-phase system or sub-system, with a single regulator serving to control the position of each electrode of each pair so as to control the current through the smelting furnace.
  • control of electrode positions in smelting furnaces usually required a regulator for each individual electrode, which regulated according to constant impedance by measuring the potential between each electrode an-d the furnace bottom.
  • Regulation based on constant furnace current has heretofore not been utilized in multielectrode smelting furnaces in which pairs of electrodes are connected in series within each single-phase system or sub-system. With such an arrangement, current could remain constant although there might be a wide divergence in the positions of the series-connected electrodes, i.e., the degree of immersion of one electrode in the furnace charge may result in a very high effective resistance between the electrode and the furnace bottom, while the degree of immersion of the other electrode may be such that a very low effective resistance exists between the electrode and the furnace bottom.
  • the present invention is directed toward preventing such a disparity between the degrees of immersion of pairs of series-connected electrodes. This is accomplished by comparing the potentials between the furnace bottom and each electrode and actuating a differential relay in response to a sufficiently large difference between these two potentials.
  • the differential relay thus actuated controls the electrode hoist mechanism and causes this mechanism to adjust the position of only one electrode so as to maintain a substantially equal degree of immersion of each electrode of the p-air within a predetermined range.
  • A. second differential relay responds to differences between the current in the primary winding of the furnace transformer and the voltage across the secondary winding to determine the direction in which the electrodes or the selected electrode must be moved.
  • FIG. 1 is a schematic diagram of a control circuit embodying the present invention.
  • FIG. 2 is a schematic diagram of an electromagnetic hoist.
  • Electrodes 1 and 2 are inserted into a furnace 4 so as to be partially immersed in a charge 6. Below the charge is a melt 8 which is formed electrothermically as a result of current flowing between electrodes 1 and 2 and the furnace bottom 10.
  • Power transformer 12 has its adjustable primary winding 14 connected to a suitable source of power.
  • the secondary winding 16 of power transformer 12 has its first and second terminals connected to the upper ends of electrodes y1 and 2, respectively.
  • the potentials between electrodes 1 and 2 and the furnace bottom 10 are impressed across the coils 18 and 20, respectively, of differential relay 22, which also includes ganged armatures 24 and 26 which are normally pressed between contact pairs 28 and 30. Contact pairs 28 and 30 are connected to the electrode hoist mechanism 32.
  • a second differential relay 34 includes contacts 36 and 38 which are connected respectively to armatures 24 and 26 of relay 22.
  • Relay 34 further includes an armature 40 which is normally in a neutral position, i.e., not in contact with either of contacts 36 or 38, and coils 42 and 44.
  • a double-pole, double-throw switch 46 enables coil 44 to be connected either across secondary winding 16 of power transformer l12- in series with a variable. resistance 48 as shown, or, when constant furnace current is d sired, across a constant reference voltage.
  • Coil 42 is connected across a current-sensing coil S0, which detects the current flowing in the primary winding 14 of power transformer 12, Current-sensing coil 50 is shunted by a variafble resistance 52 to enable adjustment of the current through coil 42.
  • Armature 40 of the differential relay 34 is connected to one of the power input terminals for the electrode hoist mechanism 32.
  • FIG. 2 schematically illustrates one possible form of the hoist apparatus 32.
  • this ligure illustrates an electromagnetic type of hoist apparatus, which, when connected into the circuit of FIG. l, as shown therein, will serve to raise or lower both of the electrodes 1 and 2 or a selected one of the electrode pair.
  • This hoist apparatus consists of a first pair of windings 54 and 56 associated with a moveable magnetic core 58 which is mechanically connected to electrode 1; and a second pair of lwindings 60 and 62 associated with a moveable magnetic core 64 which is mechanically connected to electrode 2.
  • Winding 54 is connected in series between the left contact of contact pair 28 and ground; winding 56 is connected in series between the left contact of contact pair 30 and ground; winding 60 is connected in series between the right contact of contact pair 28 and ground; and winding 62 is connected in series between the right contact of contact pair 30 and ground.
  • the present Vinvention is primarily concerned with electrical reduction furnaces in which the resistant medium is formed by a charge introduced into the furnace, it Should be understood that the invention has applications in other fields. For example, it could be utilized in electric boilers. Also, the present invention may be employed with either an alternating current powered furnace or a direct current powered furnace. Various equivalents of the control circuit components will be obvious to one knowledgable in the art.
  • An automatically-controlled electric smelting furnace system comprising:
  • hoist means for adjusting the position of said at least one pair of electrodes or of either one of said at least one pair of electrodes
  • said means for applying electric potential is a transformer having a core and primary and secondary windings, said at least one pair of electrodes being connected in series with said secondary winding and with each other.
  • switching means for selectively connecting said second coil of said differential relay either in series with a variable resistance across said secondary winding of said transformer or across a constant reference voltage source.
  • said relay means responsive to differences in the potentials from the electrodes to the furnace bottom comprises first and second ganged armatures, a pair of normallyclosed contacts associated with each of said armatures, and iirst and second coils associated with at least one of said armatures, said first and second armatures being electrically connected respectively to said iirst and second contacts of said differential relay of said means responsive to fluctuations in furnace current, said contact pairs being electrically connected to said hoist means, and said rst and second coils being connected across said furnace bottom and the rst and second electrodes, respectively, of said at least one pair of electrodes.
  • said hoist means comprises:

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Furnace Details (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Discharge Heating (AREA)
  • Earth Drilling (AREA)
US796769A 1968-02-10 1969-02-05 Control circuit for automatic positioning of pairs of electrodes in smelting furnaces Expired - Lifetime US3520978A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NO0522/68A NO117138B (enrdf_load_stackoverflow) 1968-02-10 1968-02-10

Publications (1)

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US3520978A true US3520978A (en) 1970-07-21

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US796769A Expired - Lifetime US3520978A (en) 1968-02-10 1969-02-05 Control circuit for automatic positioning of pairs of electrodes in smelting furnaces

Country Status (7)

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US (1) US3520978A (enrdf_load_stackoverflow)
JP (1) JPS4827259B1 (enrdf_load_stackoverflow)
FR (1) FR2001708A1 (enrdf_load_stackoverflow)
GB (1) GB1209133A (enrdf_load_stackoverflow)
NO (1) NO117138B (enrdf_load_stackoverflow)
YU (1) YU32802B (enrdf_load_stackoverflow)
ZM (1) ZM869A1 (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3732350A (en) * 1970-12-03 1973-05-08 British Iron Steel Research Power control
US4075414A (en) * 1974-11-29 1978-02-21 Leybold-Heraeus Gmbh & Co. Kg Apparatus for regulating the immersion depth of electrodes in electrode-melting furnaces
US4273948A (en) * 1978-10-31 1981-06-16 Centro Sperimentale Metallurgico S.P.A. Electrode height control in electro-slag remelting processes
US4483008A (en) * 1982-01-26 1984-11-13 Owens-Corning Fiberglas Corporation Arc gap controller for glass-melting furnace
CN110715554A (zh) * 2019-11-14 2020-01-21 中冶赛迪工程技术股份有限公司 炉底开出式直流电弧炉底电极电缆自动对接装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721948A (en) * 1953-02-10 1955-10-25 Ohio Ferro Alloys Corp Automatic voltage and electrode control for electric-arc furnaces
US3376374A (en) * 1964-10-30 1968-04-02 Westinghouse Electric Corp Polyphase arc furnace with control system to raise one electrode prior to all electrodes striking an arc

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721948A (en) * 1953-02-10 1955-10-25 Ohio Ferro Alloys Corp Automatic voltage and electrode control for electric-arc furnaces
US3376374A (en) * 1964-10-30 1968-04-02 Westinghouse Electric Corp Polyphase arc furnace with control system to raise one electrode prior to all electrodes striking an arc

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3732350A (en) * 1970-12-03 1973-05-08 British Iron Steel Research Power control
US4075414A (en) * 1974-11-29 1978-02-21 Leybold-Heraeus Gmbh & Co. Kg Apparatus for regulating the immersion depth of electrodes in electrode-melting furnaces
US4273948A (en) * 1978-10-31 1981-06-16 Centro Sperimentale Metallurgico S.P.A. Electrode height control in electro-slag remelting processes
US4483008A (en) * 1982-01-26 1984-11-13 Owens-Corning Fiberglas Corporation Arc gap controller for glass-melting furnace
CN110715554A (zh) * 2019-11-14 2020-01-21 中冶赛迪工程技术股份有限公司 炉底开出式直流电弧炉底电极电缆自动对接装置

Also Published As

Publication number Publication date
YU26069A (en) 1975-02-28
GB1209133A (en) 1970-10-21
NO117138B (enrdf_load_stackoverflow) 1969-07-07
ZM869A1 (en) 1969-10-16
FR2001708A1 (enrdf_load_stackoverflow) 1969-09-26
YU32802B (en) 1975-08-31
JPS4827259B1 (enrdf_load_stackoverflow) 1973-08-21

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