US3743752A - Method of suppressing hot spot in arc furnace and apparatus therefor - Google Patents

Method of suppressing hot spot in arc furnace and apparatus therefor Download PDF

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Publication number
US3743752A
US3743752A US00221278A US3743752DA US3743752A US 3743752 A US3743752 A US 3743752A US 00221278 A US00221278 A US 00221278A US 3743752D A US3743752D A US 3743752DA US 3743752 A US3743752 A US 3743752A
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United States
Prior art keywords
furnace
wall
box
temperature
electrode
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Expired - Lifetime
Application number
US00221278A
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English (en)
Inventor
H Furuhashi
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Daido Steel Co Ltd
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Daido Steel Co Ltd
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Publication date
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/52—Manufacture of steel in electric furnaces
    • C21C5/5211—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces heated electrically, with or without any other source of heat
    • F27B3/085—Arc furnaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
    • F27D21/0014—Devices for monitoring temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D9/00—Cooling of furnaces or of charges therein
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D9/00—Cooling of furnaces or of charges therein
    • F27D2009/0002—Cooling of furnaces
    • F27D2009/004—Cooling of furnaces the cooling medium passing a waterbox
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0001—Heating elements or systems
    • F27D99/0006—Electric heating elements or system
    • F27D2099/0021—Arc heating
    • 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
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to a method of suppressing hot spots in an electric arc furnace particularly electric arc furnaces for use in manufacturing steel, and an apparatus pertaining to said method.
  • the quantity of the hot spots in question is proportioned to the product obtained by multiplying the electric power per electrode by the arc voltage, and accordingly, in order to reduce this quantity, it is sufficient to effect a short are by reducing the arc voltage when the electric power is of a fixed quantity.
  • shortening of the melting-down time is also feasible, as is generally known.
  • Based on this knowledge and the finding that it is most effective to apply high electric power by means of a relatively long are for the time period beginning at the time when the scrap charged in the furnace starts melting and ending at the time when the scrap in the vicinity of the electrode melts down and, thereafter to apply a large quantity of electricity by means of short arcs successively after the scrap nearest to each of the electrodes has melted down.
  • the methods to determine the melting status of scrap it has recently been proposed to change the mode of application of electricity depending on the fluctuation of current and the change of speed of the electrode drive motor.
  • One object of the present invention is to provide a method for securing the suppression of the occurrence of hot spots by overcoming the defects of the known method as above, and an .apparatus relevant to such a method.
  • Another object of the present invention is to provide a method of suppressing hot spots by determining the exact melting condition of the scrap charged in the arc furnace and appropriately altering the mode of application of electricity to the electrodes according to the thus determined melting condition of the scrap, and an apparatus relevant to such a method.
  • a further object of the present invention is to provide a method of suppressing hot spots by virtue of the construction of the arc furnace wherein a part of the furnace wall constitutes a water cooled box so as to cool the bricks surrounding it and the water cooled box per se constitutes a furnace wall which hardly wears, and an apparatus relevant to such a method.
  • a still further object of the present invention is to provide a method of suppressing hot spots through the provision of a temperature sensor equipped on the inner surface of the water cooled box wall facing the center of the furnace, said box constituting a part of the furnace wall of the arc furnace, whereby the temperature of said surface of the box wall is sensed and, in case the thus sensed temperature reaches such a level that there is a risk of the occurrence of hot spots on the furnace wall, the power supply to the electrodes is automatically adjusted by virtue of the control system; and an apparatus relevant to such a method.
  • An additional object of the present invention is to provide a method of suppressing hot spots by sensing constantly the temperature of the cooling water at the inlet and outlet or a set of outlets of the water cooled box or boxes constituting a part of the furnace wall of the arc furnace in order to adjust automatically the power supply to the electrodes by virtue of the control system in case the sensed value shows that the temperature has reached such a level that there is a risk of the occurrence of hot spots on the furnace wall, and an apparatus relevant to such a method.
  • Yet another object of the present invention is to provide a method of suppressing hot spots by fortifying the furnace wall of an arc furnace by means of a water cooled box constituting a part of said furnace wall so as to permit application of a large quantity of electricity to the electrodes without entailing hot spots and to bring about shortening of the melting-down time to contribute remarkably to increased productivity, and an apparatus relevant to such a method.
  • FIG. 1 is a central vertical sectional view of the furnace portion of the first embodiment of the present invention.
  • FIG. 2 is a horizontal sectional view of the furnace portion shown in FIG. 1 taken along the line II-II.
  • FIG. 3 is a schematic representation of the control system in the above embodiment.
  • FIG. 4 is a schematic representation of the second embodiment of the present invention.
  • FIG. 5 is a schematic representation of the third embodiment of the present invention.
  • the electrodes 3 are fitted through the furnace roof 2 placed on the furnace wall 1.
  • the water cooled boxes 4 are inlaid in the furnace wall 1 with each box being in substantial radial alignment with the adjacent electrode.
  • Each water cooled box is respectively connected with the water supply line 5 and the water drain line 6.
  • the thermocouples l7 and 18 to sense the temperature are inserted into the water cooled box 4 and their tips are welded onto the inner surface of the box wall facing the center of furnace.
  • 12 denotes the working doorway
  • l3 denotes the sludging doorway
  • 14 denotes the tapping hole.
  • thermocouples l7 and 18 are connected with the temperature sensor" 7, and this temperature sensor 7 is connected with the comparator 8 through the wire 19.
  • the comparator 8 is further connected with the program setter 9 and the recorder with" alarm device 16 through the wires 20 and 21.
  • the program setter 9 is connected with the tap changer 10 and the electrode regulator 11 through the wires 22 and 23, and both the tap changer l and theelectrode'regulator 11 are connected with the manual controller 15.
  • the necessary numerical value-of temperature is set in advance on the comparator Band then the cooling water is circulated within the water cooled box 4 through the water supply line and the water drain line 6. As the scrap charged in the furnace melts, the temperature of the wall sur-' face of the water cooled box 4 rises, this rise in temper- ;ature is sensed by thetemperature sensor 7, and the vthus'sensed numerical value is transmitted to the comparator 8.
  • FIGS. 4 and 5' representthe second and third embodiments,'respectively, of the present invention.
  • the same parts asthose in thefirst embodiment are denoted by the same numeral references so as to'dispe'nse with reiteration of the same explanation thereof.
  • thewater supply line S'andthe ,1 water drain line 6 provided for the inlet and outlet of said water cooled box are connected with the temperature sensor 7. through the wires 24. and 25.
  • the temperature sensor 7 With the melting of the scrap charged in the furnace, the temperature' of the-coolingwaterwithin the water cooled box-4 rises, thedifferfence between the temperature of the cooling water atthe inlet and theoutlet of the water cooled box 4 gradually increases,and the numerical value of this temperature difference is'sensed 'b'y the temperature sensor'7 andis transmitted to the'comparator8 f ,1 f
  • this embodiment comprises water cooled boxes 4' equal in number to the water cooled boxes 4fof the second embodiment, each box 4 being disposed between adjacent boxes '4 and connected'with the water supply line 5' and the water drain thetemperature of the'water at each inlet and outlet is line 6.
  • this embodiment shows a mode of disposition of the water cooled boxes wherein some are.
  • steps comprising: flowing coolingwater through at least one box in the furnace wall, said boxhaving an inner wall constitutinga'portion of the interior wall of the furnace; directly sensing the temperature of the surface of said inner wall of said box bytemperature sensitive means in contact with said surface; generating an electricalsignal indicative of said temperature; and'adjusting the "power supply to the electrode or electrodes of the furnace in response to said signal to suppress hot spots in the furnace.
  • the steps comprising: flowing coolingwater'through a plurality of boxes located in spaced-apart relation in the fumace wall,.said boxes'each havingan inner wall constituting a portion of the interior wall of the furnace; sensing thetemperatures of the cooling water leaving the respective boxes;'generating an electrical signal in response to differences in said temperatures; and adjusting the power supply to the electrode or electrodes of the furnace in response to said signal to suppress hot spots in the furnace.
  • an electric arc furnace having wall means defining a melting chamber, electrode means extending into the chamber and electrical power supply circuitry for supplying power to the electrode means
  • the improvement which comprises: at least one water-cooled hollow box mounted in said wall means of said furnace; said box having a wall portion constituting a portion of the interior wall of the furnace; thermocouple means for sensing, and providing an electrical signal indicative of, the temperature of the inner surface of said wall portion of said box; and means in said circuitry for adjusting the power supply to the electrode means in response to said signal when the temperature sensed by the thermocouple is higher than a prescribed temperature, thereby to suppress hot spots in the furnace.
  • an electric arc furnace having wall means defining a melting chamber, electrode means extending into the chamber and electrical power supply circuitry for supplying power to the electrode means
  • the improvement which comprises: at least one hollow box mounted in said wall means of said furnace, said box having a wall portion constituting a portion of the interior wall of the furnace; means for flowing cooling water through said box; means for sensing the temperatures of the cooling water as it enters and as it leaves said box; and means in said circuitry for adjusting the power supply to the electrode means when the difference of the temperatures of the cooling water leaving and entering the box is greater than a prescribed temperature difference, thereby to suppress hot spots in the furnace.
  • an electric arc furnace having wall means defining a melting chamber, electrode means extending into the chamber and electrical power supply circuitry for supplying power to the electrode means
  • the improvement which comprises: a plurality of spaced-apart hollow boxes mounted in said wall means of said furnace, each of said boxes having a wall portion constituting a portion of the interior wall of the furnace; means for flowing cooling water through said boxes; means for sensing the temperatures of the cooling water leaving the respective boxes, and means in said circuitry for adjusting the power supply to the electrode means when the temperature difference of the cooling water leaving the respective boxes is greater than a prescribed temperature difference, thereby to suppress hot spots in the furnace.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Discharge Heating (AREA)
US00221278A 1971-02-02 1972-01-27 Method of suppressing hot spot in arc furnace and apparatus therefor Expired - Lifetime US3743752A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP46003590A JPS5118882B1 (fi) 1971-02-02 1971-02-02

Publications (1)

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US3743752A true US3743752A (en) 1973-07-03

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Country Status (4)

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US (1) US3743752A (fi)
JP (1) JPS5118882B1 (fi)
DE (1) DE2204882B2 (fi)
IT (1) IT948948B (fi)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3883677A (en) * 1973-04-05 1975-05-13 Asea Ab Electric arc furnace having side-wall lining protection
US3885082A (en) * 1973-04-19 1975-05-20 Asea Ab Electric arc furnace side-wall protection arrangement
US3952138A (en) * 1974-05-02 1976-04-20 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Power control system for electric arc or refining furnace electrically directly coupled to independent power generating unit or units
US3956572A (en) * 1975-03-11 1976-05-11 Pennsylvania Engineering Corporation Cooling means for electric arc furnaces
FR2331233A2 (fr) * 1975-11-06 1977-06-03 Asea Ab Four a arc a courant continu
EP0043329A1 (fr) * 1980-07-01 1982-01-06 Clecim Sa Four électrique à arcs à fonctionnement contrôlé
WO2002039043A1 (en) * 2000-11-13 2002-05-16 Elkem Asa Method for controlling the temperature of components in high temperature reactors
US11175094B2 (en) * 2018-10-08 2021-11-16 Systems Spray-Cooled, Inc. Dynamic cooling of a metallurgical furnace

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3103883C2 (de) * 1981-02-05 1983-01-20 Krupp Stahl Ag, 4630 Bochum Verfahren zur Unterdrückung von überhitzten Stellen in kühlmitteldurchflossenen Wand- oder Deckenelementen eines Elektrolichtbogenofens
DE19529924C1 (de) * 1995-08-01 1996-10-31 Mannesmann Ag Lichtbogenofen und Verfahren zur Vermeidung von Überhitzungen der Ofenwand
DE19711453C2 (de) * 1997-03-19 1999-02-25 Siemens Ag Verfahren zur Regelung bzw. Steuerung eines Schmelzprozesses in einem Drehstrom-Lichtbogenofen

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3183294A (en) * 1962-04-09 1965-05-11 Ohio Crankshaft Co Temperature control apparatus
US3190626A (en) * 1962-10-01 1965-06-22 Union Carbide Corp Support means for a refractory lined furnace
US3622678A (en) * 1968-05-14 1971-11-23 Ass Elect Ind Electrode feed arrangements

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3183294A (en) * 1962-04-09 1965-05-11 Ohio Crankshaft Co Temperature control apparatus
US3190626A (en) * 1962-10-01 1965-06-22 Union Carbide Corp Support means for a refractory lined furnace
US3622678A (en) * 1968-05-14 1971-11-23 Ass Elect Ind Electrode feed arrangements

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3883677A (en) * 1973-04-05 1975-05-13 Asea Ab Electric arc furnace having side-wall lining protection
US3885082A (en) * 1973-04-19 1975-05-20 Asea Ab Electric arc furnace side-wall protection arrangement
US3952138A (en) * 1974-05-02 1976-04-20 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Power control system for electric arc or refining furnace electrically directly coupled to independent power generating unit or units
US3956572A (en) * 1975-03-11 1976-05-11 Pennsylvania Engineering Corporation Cooling means for electric arc furnaces
FR2304046A1 (fr) * 1975-03-11 1976-10-08 Lectromelt Corp Procede de refroidissement de la paroi externe d'une enceinte metallurgique et dispositif pour sa mise en oeuvre
FR2331233A2 (fr) * 1975-11-06 1977-06-03 Asea Ab Four a arc a courant continu
EP0043329A1 (fr) * 1980-07-01 1982-01-06 Clecim Sa Four électrique à arcs à fonctionnement contrôlé
FR2486346A1 (fr) * 1980-07-01 1982-01-08 Clesid Sa Four electrique a arcs a conduite guidee
WO2002039043A1 (en) * 2000-11-13 2002-05-16 Elkem Asa Method for controlling the temperature of components in high temperature reactors
US11175094B2 (en) * 2018-10-08 2021-11-16 Systems Spray-Cooled, Inc. Dynamic cooling of a metallurgical furnace
US11692774B2 (en) 2018-10-08 2023-07-04 Systems Spray-Cooled, Inc. Dynamic cooling of a metallurgical furnace

Also Published As

Publication number Publication date
DE2204882B2 (de) 1977-04-14
IT948948B (it) 1973-06-11
DE2204882A1 (de) 1972-08-03
JPS5118882B1 (fi) 1976-06-14

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