US3478156A - Polyphase stirring of molten metal - Google Patents

Polyphase stirring of molten metal Download PDF

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Publication number
US3478156A
US3478156A US705848A US3478156DA US3478156A US 3478156 A US3478156 A US 3478156A US 705848 A US705848 A US 705848A US 3478156D A US3478156D A US 3478156DA US 3478156 A US3478156 A US 3478156A
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United States
Prior art keywords
stirring
sections
coil
phase
polyphase
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Expired - Lifetime
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US705848A
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English (en)
Inventor
Robert Sidney Segsworth
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Park Ohio Holdings Inc
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Ajax Magnethermic Corp
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Priority claimed from SE10350/66*[A external-priority patent/SE346043B/xx
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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
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H05B6/067—Control, e.g. of temperature, of power for melting furnaces
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/10—Image acquisition
    • G06V10/12—Details of acquisition arrangements; Constructional details thereof
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/20—Image preprocessing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/20—Image preprocessing
    • G06V10/24—Aligning, centring, orientation detection or correction of the image
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/20—Image preprocessing
    • G06V10/28—Quantising the image, e.g. histogram thresholding for discrimination between background and foreground patterns
    • 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
    • H05B2213/00—Aspects relating both to resistive heating and to induction heating, covered by H05B3/00 and H05B6/00
    • H05B2213/02—Stirring of melted material in melting furnaces

Definitions

  • This invention relates to a method and apparatus for polyphase stirring and/or melting from a single phase source of alternating current.
  • An object of this invention is to achieve increased stirring in a coreless melting or holding furnace.
  • a further object of this invention is to provide polyphase stirring in a coreless melting or holding furnace with a single phase source.
  • a still further object of this invention is to provide said polyphase stirring but eliminating violent agitation of the melt surface.
  • Another object of this invention is to provide polyphase stirring of molten metal with improved electrical efiiciency.
  • a further object of this invention is to provide a coreless melting or holding furnace wherein transfer from single phase melting to polyphase stirring is accomplished in a relatively simple, economical and expeditious manner.
  • Another object of this invention is to provide for transfer from polyphase stirring in a coreless melting or holding furnace to single phase melting.
  • a still further object of this invention is to provide stirring means for a coreless melting or holding furnace wherein the direction of stirring may be readily reversed.
  • a still further object is to provide polyphase stirring of molten metal in pipe lines to move or pump the same.
  • FIGURE 1 is a longitudinal vertical sectional view of a furnace embodying the invention including electrical circuit connections;
  • FIGURE 1A is a view showing a phase vector diagram of the coil currents of FIGURE 1;
  • FIGURE 2 is a View similar to FIGURE 1 showing a switching connection between the two coil sections of FIGURE 1;
  • FIGURE 2A is a phase vector diagram identical with that of FIGURE 1A showing in dotted lines the phase angle of the current 1B when the switch of FIGURE 2 is closed;
  • FIGURE 3 is a view similar to FIGURE 1, but showing a modification of the invention wherein four coil sections are used;
  • FIGURE 3A is a phase vector diagram of the coil curcents of FIGURE 3;
  • FIGURE 4 is a view similar to FIGURE 1 of another United States Patent 0 Patented Nov. 11, 1969 modification of the invention disclosing switches for reversing the direction of flow of the metal in a furnace;
  • FIGURE 4A is a phase vector diagram of the coil curcerzlts of FIGURE 4 during polyphase upward stirring
  • FIGURE 4B is a phase vector diagram of the coil currents of FIGURE 4 during melting.
  • a coreless melting or holding furnace 10 and, as shown, with a crucible having a refractory lining 10', surrounded by a coil of two or more sections. Sections of said coil are connected to a single phase alternating current power source and other of said sections are unconnected thereto.
  • the said alternating current is applied so that the phase preferably shifts by the same angle from one coil section to the next, as shown in the current vector FIGURES 11:, 2a, 3a and 4a, wherefor positive unidirectional motion of the outer portion of the melt in the direction in which the travelling magnetic field moves is achieved.
  • a pair of coaxial spaced coils A and B surround the furnace.
  • the bottom coil A is shown supplied with alternating current from a single phase generator, frequency multiplier, or other a1- ternating current source 11.
  • a bank of capacitors 12, 12' connected in parallel in the input line are adapted to be added or subtracted by switching means 13 to improve the power factor.
  • the coaxial coil section or upper section B is connected to a bank of capacitors 14, 14, similar to those designated at 12, 12, and said capacitors 14, 14' are adapted to be switched in and out as required by switch means 15.
  • the coil section B is not connected to the power source.
  • the amount of capacitors connected to the upper section may be adjusted to produce resonance or near resonance in tune with the circuit of coil section A with the result that a very substantial upward stirring of the melt at the sides of the crucible 10 results with corresponding downward flow in the center section of the melt as shown in FIGURE 1.
  • the phase angle of the current 1 through the upper section B lags the current in the lower section 1 by approximately as shown in the current vector diagram FIGURE 1a.
  • phase angle shown in FIGURE la can be adjusted within a wide range from substantially less than 90 to substantially more than 90 without significantly affecting the current itself or the upward stirring effect produced. It is generally found desirable to tune the upper coil close to resonance.
  • Coreless furnace installations of the prior art provide at least two separate sources of voltage with a substantial phase angle between them to accomplish polyphase stirring and are usually designed to operate at maximum power for melting from a single-phase high power supply and at a reduced power level for polyphase stirring by transferring each coil section from such single phase high power supply to one phase of a polyphase supply, since it is normally not desirable to melt in the polyphase mode since a significant loss of electrical efliciency would take place and a strong agitation of the melt surface which could be deleterious and detrimetal to the metallurgy.
  • FIGURE 2 an arrangement for transferring the system of FIGURE 1 from melting to stirring is illustrated. It will be noted that a fixed electrical connection 16 between the bottom terminals of the two coil sections B and A and a tie-line 18 with a single switch means 17 between the upper terminals of coil sections B and A has been added to the showing of FIGURE 1. Conversion from stirring to melting is accomplished, in this form of the invention, by closing the switch 17 as indicated by dotted lines so that both sections B and A now operate as parallel sections of a single-phase coil in a conventional manner. The capacitors 12, 12, 14, 14 can then be readjusted manually or automatically, act jointly and are fully utilized to correct the power factor of the single phase furnace.
  • taps may be provided on the induction coil or a transformer interposed between the induction coil and the capacitors, or a transformer interposed between said coil and the capacitors and that in such event the tap or transformer setting may be adjusted when transferring from stirring to melting operation. It is believed that such tap or transformer setting adjustments are of the type readily understood by those skilled in the art to which the present invention appertains.
  • the generator or other single-phase power source is connected to coils A and C and this connection may be in series or in parallel.
  • coils must be connected in a way, as shown, that their electro-magnetic fields buck or oppose each other.
  • I and I as shown in FIGURE 3 are substantially 180 out of phase.
  • a battery of capacitors as shown, with fixed and variable capacity, is connected, in the form of FIGURE 3, to sections B and D in series, but again in such a manner that the current in these two sections will magnetically buck each other or be 180 out of phase with each other.
  • FIGURE 4 a switching arrangement -is disclosed wherefore transfer may be made from polyphase stirring to single-phase melting with the basic four phase stirring connection shown in FIGURE 3.
  • a switch 30 is provided to connect sections B and D to the generator or other single phase source so that all four sections A, B, C and D, respectively, may be placed in phase for melting rather than 180 apart, as required in stirring.
  • the circuit of FIGURE 4 provides that in the melting operation, sections A and C and B and D are connected in series and both groups then connection in parallel to the single phase source or generator. Each section then operates at approximately /2 the generator voltage and all four sections, A, B, C and D contribute approximately the same power.
  • coil taps or transformers may be employed in the form of the invention as shown in FIGURE 4.
  • FIGURE 4b is a vector diagram of the currents of sections A, B, C and D during the melting operation
  • FIGURE 4a is a vector diagram of the currents I I I and I during the stirring operation and in said operation the current in each section, similarly to that shown in FIGURE 3a, lags behind that in the section below it by approximately and also produces a full-wave upward travelling field producing upward flow in the outer layers of the melt.
  • the power source may be connected to the upper sections D and B and capacitance only to the lower sections C and A so that the current in the lower section will lag the upper section and thus producing downward flow, as indicated in dotted line arrows, in the outer portion of the melt and upward flow in the center of the melt. This may be effected, for example, by closing switch 30 and opening switch 40 shown in dotted lines.
  • the polarity of coil sections C and D is reversed as by switch means 21, 32 so that the currents in sections A and C, and in B and D, respectively, will be in phase for melting rather than apart, as required for stirring.
  • the switch 30, shown in FIGURE 4 is similar to the switch 17 in FIGURE 2, employed to provide a tieline connection to the upper sections, wherefore sections A, B, C and D are all energized from the same singlephase power source and maximum power is obtained for melting.
  • the invention may be opearted at the normal line frequency of 60 cycles, or preferably at other frequencies such as a 180 cycle, 960 cycle, 30 cycles, etc. Such frequencies are normally available in single-phase form, whereas, three-phase supply is generally available from 60 cycle.
  • a plural-section coil comprising separate coil sections surrounding different portions of said container, a single phase power supply, said coil sections being coaxial and axially adjacent each other, a first of said sections being connected and energized by said power supply, a second of said sections being connected to capacitance and unconnected to said power supply, the current in said second unconnected section being substantially displaced in phase from the current in such first section thereby producing polyphase unidirectional stirring movement in the molten metal.
  • a four-section coil comprising four separate coil sections surrounding different portions of said container, a single phase power supply, said coil sections being coaxial and axially adjacent each other, a first of said sections being connected and energized by said power supply, a second of said sections being serially connected to capacitance and unconnected to said power supply, a third of said sections being connected and energized by said power supply, a fourth of said sections being serially connected to capacitance and unconnected to said power supply, the phase angle of current in each of said sections lagging that of the current in the preceding section by substantially thereby producing polyphase unidirectional stirring movement in the molten metal.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Multimedia (AREA)
  • Theoretical Computer Science (AREA)
  • Electromagnetism (AREA)
  • General Induction Heating (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Character Input (AREA)
  • Furnace Details (AREA)
  • Character Discrimination (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
US705848A 1966-12-21 1968-02-15 Polyphase stirring of molten metal Expired - Lifetime US3478156A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE10350/66*[A SE346043B (es) 1966-12-21 1966-12-21
US70584868A 1968-02-15 1968-02-15

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US3478156A true US3478156A (en) 1969-11-11

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US (1) US3478156A (es)
JP (1) JPS49305B1 (es)
DE (1) DE1549673A1 (es)
DK (1) DK119181B (es)
GB (2) GB1166759A (es)
NL (1) NL6710521A (es)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3878073A (en) * 1972-07-14 1975-04-15 Univ Ohio State Res Found Oxygen exchange with liquid metals
US3887721A (en) * 1972-12-20 1975-06-03 Armco Steel Corp Metallic coating method
US4238637A (en) * 1977-07-27 1980-12-09 Elphiac Sa Coreless induction furnace
US4300031A (en) * 1977-08-05 1981-11-10 Tocco-Stel Method for induction butt-welding metal parts, in particular parts of irregular cross-section
WO1982002339A1 (en) * 1981-01-09 1982-07-22 Robert W Rand Induction heating method and apparatus for use in causing necrosis of neoplasm
WO1987006332A1 (en) * 1986-04-16 1987-10-22 Asea Brown Boveri Ab Arrangement in steel manufacturing by means of inductive stirring
WO1988005831A1 (en) * 1987-02-03 1988-08-11 Otto Junker Gmbh Process for operating hot metallization ovens
US5012487A (en) * 1989-06-14 1991-04-30 Inductotherm Europe Limited Induction melting
US5250777A (en) * 1990-04-02 1993-10-05 Inductotherm Corp. Method and apparatus for variable phase induction heating and stirring
US5416796A (en) * 1992-06-02 1995-05-16 National Research Institute For Metals Float melting apparatus and method employing axially movable crucibles
US5889812A (en) * 1994-02-11 1999-03-30 Otto Junker Gmbh Process for the operation of coreless induction melting furnaces or holding furnances and an electrical switching unit suitable for the same
US6618426B1 (en) * 1999-02-26 2003-09-09 Centre National De La Recherche Scientifique Electromagnetic stirring of a melting metal
EP1405019A2 (en) * 2001-05-22 2004-04-07 Inductotherm Corp. Furnace with bottom induction coil
WO2005072207A3 (en) * 2004-01-17 2006-08-03 Consarc Corp Cold crucible induction furnace with eddy current damping
US20080063025A1 (en) * 2004-12-08 2008-03-13 Fishman Oleg S Electric Induction Heating, Melting and Stirring of Materials Non-Electrically Conductive in the Solid State
US20090129429A1 (en) * 2007-11-17 2009-05-21 Fishman Oleg S Melting and mixing of materials in a crucible by electric induction heel process
AU2005313972B2 (en) * 2004-12-08 2012-04-19 Inductotherm Corporation Electric induction control system
US8728196B2 (en) 2007-10-12 2014-05-20 Ajax Tocco Magnethermic Corporation Semi-liquid metal processing and sensing device and method of using same
US9574826B2 (en) 2012-09-27 2017-02-21 Ajax Tocco Magnethermic Corporation Crucible and dual frequency control method for semi-liquid metal processing

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ZA83844B (en) * 1982-02-12 1983-11-30 British Steel Corp Treatment of molten materials
DD213265A1 (de) * 1982-12-31 1984-09-05 Zeiss Jena Veb Carl Elektromagnetisch betriebener wandler
GB2200979B (en) * 1987-02-14 1990-08-29 Inductotherm Europ Induction melting
WO1995026619A1 (de) * 1994-03-25 1995-10-05 Otto Junker Gmbh Induktionstiegelofen mit mindestens zwei parallel an einen schwingkreisumrichter angeschlossenen spulen
JP2954896B2 (ja) * 1997-01-09 1999-09-27 核燃料サイクル開発機構 コールドクルーシブル誘導溶融炉からの溶融物抜き出し装置
JP2007167857A (ja) * 2005-12-19 2007-07-05 Yamaichi Kinzoku Kk 溶融金属の処理方法
JP2008241197A (ja) * 2007-03-28 2008-10-09 Fuji Electric Systems Co Ltd 通電加熱装置
JP5474700B2 (ja) * 2010-08-03 2014-04-16 一般財団法人電力中央研究所 誘導加熱による溶融炉

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1822539A (en) * 1929-03-09 1931-09-08 Ajax Electrothermic Corp Induction electric furnace
US2052649A (en) * 1932-09-10 1936-09-01 Nat Aniline & Chem Co Inc Electrically heated apparatus and method of operating
US2803689A (en) * 1956-04-02 1957-08-20 Nat Res Corp Electric induction furnace
CA668542A (en) * 1963-08-13 Herschmann Heinrich Induction heating apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA668542A (en) * 1963-08-13 Herschmann Heinrich Induction heating apparatus
US1822539A (en) * 1929-03-09 1931-09-08 Ajax Electrothermic Corp Induction electric furnace
US2052649A (en) * 1932-09-10 1936-09-01 Nat Aniline & Chem Co Inc Electrically heated apparatus and method of operating
US2803689A (en) * 1956-04-02 1957-08-20 Nat Res Corp Electric induction furnace

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3878073A (en) * 1972-07-14 1975-04-15 Univ Ohio State Res Found Oxygen exchange with liquid metals
US3887721A (en) * 1972-12-20 1975-06-03 Armco Steel Corp Metallic coating method
US4238637A (en) * 1977-07-27 1980-12-09 Elphiac Sa Coreless induction furnace
US4300031A (en) * 1977-08-05 1981-11-10 Tocco-Stel Method for induction butt-welding metal parts, in particular parts of irregular cross-section
WO1982002339A1 (en) * 1981-01-09 1982-07-22 Robert W Rand Induction heating method and apparatus for use in causing necrosis of neoplasm
US4392040A (en) * 1981-01-09 1983-07-05 Rand Robert W Induction heating apparatus for use in causing necrosis of neoplasm
EP0208338A2 (en) * 1981-01-09 1987-01-14 Robert W. Rand Induction heating apparatus
EP0208338A3 (en) * 1981-01-09 1987-05-13 Robert W. Rand Induction heating apparatus
WO1987006332A1 (en) * 1986-04-16 1987-10-22 Asea Brown Boveri Ab Arrangement in steel manufacturing by means of inductive stirring
JPH01500526A (ja) * 1986-04-16 1989-02-23 アセア　アクチーボラグ 誘導攪拌による製鋼用装置
WO1988005831A1 (en) * 1987-02-03 1988-08-11 Otto Junker Gmbh Process for operating hot metallization ovens
US5135781A (en) * 1987-02-03 1992-08-04 Otto Junker Gmbh Procedure for operating a hot metallizing furnace
US5012487A (en) * 1989-06-14 1991-04-30 Inductotherm Europe Limited Induction melting
US5250777A (en) * 1990-04-02 1993-10-05 Inductotherm Corp. Method and apparatus for variable phase induction heating and stirring
US5416796A (en) * 1992-06-02 1995-05-16 National Research Institute For Metals Float melting apparatus and method employing axially movable crucibles
US5889812A (en) * 1994-02-11 1999-03-30 Otto Junker Gmbh Process for the operation of coreless induction melting furnaces or holding furnances and an electrical switching unit suitable for the same
US6618426B1 (en) * 1999-02-26 2003-09-09 Centre National De La Recherche Scientifique Electromagnetic stirring of a melting metal
EP1405019A2 (en) * 2001-05-22 2004-04-07 Inductotherm Corp. Furnace with bottom induction coil
EP1405019A4 (en) * 2001-05-22 2006-08-09 Inductotherm Corp DOMESTIC INDUCTION COIL OVEN
WO2005072207A3 (en) * 2004-01-17 2006-08-03 Consarc Corp Cold crucible induction furnace with eddy current damping
US20070147463A1 (en) * 2004-01-17 2007-06-28 Roberts Raymond J Cold crucible induction furnace with eddy current damping
US7848383B2 (en) 2004-01-17 2010-12-07 Consarc Corporation Cold crucible induction furnace with eddy current damping
US20080063025A1 (en) * 2004-12-08 2008-03-13 Fishman Oleg S Electric Induction Heating, Melting and Stirring of Materials Non-Electrically Conductive in the Solid State
US9370049B2 (en) 2004-12-08 2016-06-14 Inductotherm Corp. Electric induction heating, melting and stirring of materials non-electrically conductive in the solid state
AU2005313972B2 (en) * 2004-12-08 2012-04-19 Inductotherm Corporation Electric induction control system
US8728196B2 (en) 2007-10-12 2014-05-20 Ajax Tocco Magnethermic Corporation Semi-liquid metal processing and sensing device and method of using same
US20140010257A1 (en) * 2007-11-17 2014-01-09 Inductotherm Corp. Melting and Mixing of Materials in a Crucible by Electric Induction Heel Process
US20140010256A1 (en) * 2007-11-17 2014-01-09 Inductotherm Corp. Melting and Mixing of Materials in a Crucible by Electric Induction Heel Process
US20140029644A1 (en) * 2007-11-17 2014-01-30 Inductotherm Corp. Melting and Mixing of Materials in a Crucible by Electric Induction Heel Process
US8532158B2 (en) * 2007-11-17 2013-09-10 Inductotherm Corp. Melting and mixing of materials in a crucible by electric induction heel process
US9226344B2 (en) * 2007-11-17 2015-12-29 Inductotherm Corp. Melting and mixing of materials in a crucible by electric induction heel process
US9357588B2 (en) * 2007-11-17 2016-05-31 Inductotherm Corp. Melting and mixing of materials in a crucible by electric induction heel process
US20090129429A1 (en) * 2007-11-17 2009-05-21 Fishman Oleg S Melting and mixing of materials in a crucible by electric induction heel process
US9462640B2 (en) * 2007-11-17 2016-10-04 Inductotherm Corp Melting and mixing of materials in a crucible by electric induction heel process
US9574826B2 (en) 2012-09-27 2017-02-21 Ajax Tocco Magnethermic Corporation Crucible and dual frequency control method for semi-liquid metal processing

Also Published As

Publication number Publication date
DK119181B (da) 1970-11-23
DE1549673A1 (de) 1971-04-08
DE1800431A1 (de) 1971-01-21
GB1166759A (en) 1969-10-08
NL6710521A (es) 1968-01-30
GB1166789A (en) 1969-10-08
DE1800431B2 (de) 1971-06-03
JPS49305B1 (es) 1974-01-07

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