US3334171A - Vacuum furnace - Google Patents

Vacuum furnace Download PDF

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Publication number
US3334171A
US3334171A US411197A US41119764A US3334171A US 3334171 A US3334171 A US 3334171A US 411197 A US411197 A US 411197A US 41119764 A US41119764 A US 41119764A US 3334171 A US3334171 A US 3334171A
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US
United States
Prior art keywords
casing
packing
parts
opening
furnace
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
US411197A
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English (en)
Inventor
Fredrikson Bengt
Haas Gustav
Karlsson Gosta
Rydinger Mats
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ABB Norden Holding AB
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ASEA AB
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Publication date
Application filed by ASEA AB filed Critical ASEA AB
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Publication of US3334171A publication Critical patent/US3334171A/en
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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
    • H05B6/16—Furnaces having endless cores
    • H05B6/20—Furnaces having endless cores having melting channel only
    • 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
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/04—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated adapted for treating the charge in vacuum or special atmosphere
    • 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

  • VACUUM FURNACE Filed Nov. 16, 1,964 '3 Sheets-Sheet 2 IN V EN TOR BENGT FnEnRlksom gusrAv HAA$ GOSTA KARLSON ATS RYDINGER .ATTORN Ys' Aug. 1, 1967 B, FREDRlKfSON ET AL 3 33 VACUUM FURNACE 3 heets-Sheet 5 Filed Nov. 16, 1964 Rmsou BENGT FRED GUSTAV WK?
  • the present invention refers to a vacuum furnace for degassing metal melts, preferably steel.
  • the furnace comprises a hearth of arbitrary shape.
  • the invention also refers to an interchangeable inductor unit for such a furnace.
  • the furnace In vacuum melt furnaces the furnace has often been provided with stirring devices, often of electromagnetic, low frequency multiphase type. This has the advantage firstly of facilitating the retention of heat imparted to the melt by means of a heat source, and secondly of bringing the whole melt into such a circulation that all or principally all the melt is subjected to degassing.
  • stirring devices often of electromagnetic, low frequency multiphase type. This has the advantage firstly of facilitating the retention of heat imparted to the melt by means of a heat source, and secondly of bringing the whole melt into such a circulation that all or principally all the melt is subjected to degassing.
  • induction vacuum furnaces of the crucible type the whole furnace must be enclosed in a vacuum tank Where the electrical arrangements will be found within the vacuum tank, which inter alia is accompanied with risks of glowing at these parts and demands special insulating devices.
  • the possibilities of varying the geometrical shape, and size of the furnace are also limited.
  • the invention eliminates these inconveniences and is intended to be applied to furnaces of arbitrary shape.
  • the invention is characterised in that at least one interchangeable inductor unit of the submerged resistor type for heat retention and stirring of the melt is connected vacuum tightly to the furnace, without emptying and cooling down.
  • Such a furnace does not need to be enclosed in a special vacuum tank, but, like the parts of the induction unit itself, can be made vacuum tight, and at the same time the inductance coil within the unit can operate in atomspheric pressure.
  • the units may be connected to furnaces of practically all feasible geometrical shapes and sizes.
  • the invention also refers to an inductor unit of submerged resistor type, which comprises a packing for vacuum tight, interchangeable connection to a furnace body and a metallic casing enclosing the inductor unit.
  • the unit is characterized in that remote from this first mentioned packing is arranged a second vacuum packing, which electrically insulates the two parts of the cover at each side of this packing from each other, which secand packing extends from a point at the periphery of the unit through at least one space for a coil to another point at the periphery of the unit and comprises two limiting layers and an intermediate, electrically insulating portion, each layer consisting of a lining around'a part of the coil space and the intermediate portion having the form of two closed rings, each enclosing one branch of the melting loop or loops.
  • the insulating part is situated along a plane passing through a coil space parallel with the connection plate to the furnace. In such an embodiment ramming of material around a loop form is facilitated, which form consists of hardened metal.
  • a third packing is arranged (which does not need to be electrically insulating) which facilitates ramming of ceramic material also at the outer parts of the cover around the loop form. Such packing would otherwise be difiicult.
  • FIG. 1 shows perspectively an inductor unit for interchangeable application to a vacuum furnace.
  • FIG. 2 shows a section through the unit at right angles to the coil shaft;
  • FIG. 3 shows the unit seen from the side;
  • FIG. 4 shows a section through a vacuum tight, electrically insulated packing; and
  • FIG. 5 is a cross-section through the center of FIG. 2.
  • FIG. 2 To a vacuum furnace 11 (FIG. 2) of arbitrary type an inductor according to FIG. 1 is arranged to be interchangeably fastened.
  • the furnace is made vacuum tight (for example with an enclosing metal cover ofstainless, non-ferromagnetic material) and with the usual evacuation means. It is provided with one or more con- 7 nection openings (FIG. 2) for interchangeable inductor the fluid cooling from channel 13, and then the unit would not be interchangeable.
  • the inductor unit is connected through a metallic connection flange (15,. FIG. 1) and is provided with an enclosing casing formed of first, second and third parts 16a, 16b and 160, respectively, part 16a extending from this flange itself.
  • This casing also encloses a central tubular opening or space 17, open at the ends, for receiving a coil 30 wit-h iron yokes 31 (shown in broken lines in FIG. intended to be connected to the network frequency, said coil as usual being the primary circuit and a melt loop 18 being the secondary circuit, said furnace operating as a transformer.
  • the melting loop 18 is enclosed in' rammed material of'a ceramic nature (shown in FIGS. 2 and 5).
  • the casing parts are electrically insulated from each other with the object of preventing the formation of secondary electrical short circuits outside the melt.
  • the insulation is accomplished by means of an insulating packing 20 (FIGS. '1 and 2) separating the easing into two parts insulated from each other, and by a packing 19 (FIGS. 1 and2) positioned along each side of the coil space 17 (FIG. 5) and around the outer sides of the casing.
  • FIG. 4 shows a detailed view of the packing 19.
  • Packing rings 21 of electrically insulating material on each side of the coil'space 17 each form a closed ring around each branch of the melt loop 18.
  • the ring is positioned in a loop between two aluminium strips 23, fastened to one of the casing parts with screws.
  • insulating layers 25- are arranged on the screw heads 22 and outside these.
  • Strips 23 are of elongated form and are screwed to one of the flanges 32 of the casing at the packing 19.
  • the packing 19 (and 20) the casing is separated into parts electrically and magnetically insulated from each other.
  • the casing is provided with flanges running in closed form around the unit parts and on both sides of the space 17 around the unit.
  • the position of the packing 19 (and 20) makes it possi-ble to separate the unit into two (more) parts in connection with the packing of material around the melting loops 18, said loops being filled with a form.
  • the lower part of the casing (below 19) is filled with material and rammed around a loop form, after which the upper part of the casing is fastened to the packing 19 and the rest of the material is filled in and rammed around the loop form.
  • This model is made of hardened metal in the melting loop and in a loop through the furnace.
  • the unit is provided with an extra vacuum tight packing 20, which also makes possible the ramming of the material at the bottom of the unit, especially in the part 26 which lies below the lower half of the coil lining 27.
  • the coil 30 with iron yoke 31 is placed in the space 17 and as seen from FIG. 5 it operates at atmospheric pressure.
  • the casing material enclosing said space is vacuum-tight.
  • the coil 30 may thus operate without a tendency to glowing in' the winding which would otherwise appear if the coil operated in vacuum.
  • cooling loops are arranged at the coil (not shown) as well as outside the unit (24, FIG. 3 said cooling loops 24 area, for the sake of clarity, eliminated in FIGS. 1 and 2).
  • the cooling parts 24 are placed in the atmosphere. Upon leakage of condensed water in the vacuum no undesired pressure increases arise, which would otherwise involve risks. By placing the coil at atmospheric pressure and thereby operating in a conventional manner these risks are eliminated.
  • the number of units can be one, two or more and with a suitable construction of the furnace these can be interchanged without cooling down and emptying the furnace.
  • an inductor unit attached at said opening comprising a metallic casing formed of a plurality of parts, a first of said parts being positionable adjacent said wall section with the interior of the casing communicating with said opening, an electrically non-insulating, packing carried by said first casing part engageable with said wall section around said opening, a second casing part positioned adjacent said first casing part, said first and second casing parts together forming a passage therethrough in a direction parallel to the plane of said wall section to receive a coil, thereby forming two branch portions, one on each side of said opening, electrically insulating packing means between said first and second casing parts extending around each of said branch portions, and means closing the end of the second casing part remote from the first casing part.
  • said closing means comprising a third casing part positioned adjacent the end of the second casing part remote from the second casing part, and second electrically insulating packing means engaged between said second and third casing parts.
  • ceramic means within said casing having a U-shaped passage therein communicating at each end with said opening to form a melting loop.
  • said packing means comprising inner and outer strips and an electrically insulating portion between said strips.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Furnace Details (AREA)
  • General Induction Heating (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
US411197A 1964-05-20 1964-11-16 Vacuum furnace Expired - Lifetime US3334171A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE6095/64A SE317146B (xx) 1964-05-20 1964-05-20

Publications (1)

Publication Number Publication Date
US3334171A true US3334171A (en) 1967-08-01

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ID=20267891

Family Applications (1)

Application Number Title Priority Date Filing Date
US411197A Expired - Lifetime US3334171A (en) 1964-05-20 1964-11-16 Vacuum furnace

Country Status (5)

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US (1) US3334171A (xx)
AT (1) AT266193B (xx)
DE (1) DE1458804B1 (xx)
GB (1) GB1100783A (xx)
SE (1) SE317146B (xx)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3394216A (en) * 1965-11-10 1968-07-23 Dresser Ind Core-type induction furnace
US3440323A (en) * 1966-07-06 1969-04-22 Ass Elect Ind Refractory crucibles
US3485928A (en) * 1967-02-03 1969-12-23 Hitachi Cable Inductor for low-frequency induction furnace
US3522355A (en) * 1966-10-19 1970-07-28 Ass Elect Ind Induction heating arrangements

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB170046A (en) * 1920-06-09 1921-10-10 James Raymond Wyatt Improvements in and relating to induction furnaces having unidirectional circulation
US3098887A (en) * 1957-11-28 1963-07-23 Calamari Elio Ezio Industrial frequency electric induction furnace with submerged horizontal channel for the melting of any metal

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE649491C (de) * 1937-08-26 Hirsch Kupfer Und Messingwerke Niederfrequenzinduktionsofen
DE374378C (de) * 1923-04-23 Ajax Metal Company Inc Elektrischer Induktionsschmelzofen
US2140607A (en) * 1935-10-19 1938-12-20 American Metal Co Ltd Method of and apparatus for casting deoxidized copper
GB702225A (en) * 1951-04-04 1954-01-13 Frederic Barnes Waldron Improvements in the manufacture of steel

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB170046A (en) * 1920-06-09 1921-10-10 James Raymond Wyatt Improvements in and relating to induction furnaces having unidirectional circulation
US3098887A (en) * 1957-11-28 1963-07-23 Calamari Elio Ezio Industrial frequency electric induction furnace with submerged horizontal channel for the melting of any metal

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3394216A (en) * 1965-11-10 1968-07-23 Dresser Ind Core-type induction furnace
US3440323A (en) * 1966-07-06 1969-04-22 Ass Elect Ind Refractory crucibles
US3522355A (en) * 1966-10-19 1970-07-28 Ass Elect Ind Induction heating arrangements
US3485928A (en) * 1967-02-03 1969-12-23 Hitachi Cable Inductor for low-frequency induction furnace

Also Published As

Publication number Publication date
DE1458804B1 (de) 1970-07-09
SE317146B (xx) 1969-11-10
AT266193B (de) 1968-11-11
GB1100783A (en) 1968-01-24

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