US3431345A - Electrical resistance furnaces - Google Patents

Electrical resistance furnaces Download PDF

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Publication number
US3431345A
US3431345A US682227A US3431345DA US3431345A US 3431345 A US3431345 A US 3431345A US 682227 A US682227 A US 682227A US 3431345D A US3431345D A US 3431345DA US 3431345 A US3431345 A US 3431345A
Authority
US
United States
Prior art keywords
crucible
tube
electrical resistance
enclosure
casing
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
US682227A
Other languages
English (en)
Inventor
Kenneth Francis Faulkner
Alan Walter Plume
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Heatlock Ltd
Original Assignee
Heatlock Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Heatlock Ltd filed Critical Heatlock Ltd
Application granted granted Critical
Publication of US3431345A publication Critical patent/US3431345A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • F27D11/02—Ohmic resistance heating
    • 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
    • F27B14/00—Crucible or pot furnaces
    • F27B14/04—Crucible or pot furnaces adapted for treating the charge in vacuum or special atmosphere

Definitions

  • This invention relates to electrical resistance furnaces, and is concerned, more particularly, with such furnaces of the type which includes a crucible for molten metal contained within a sealed enclosure so that the molten metal may be extracted, when required for use, from the crucible under the influence of pressure or vacuum.
  • the present invention consists in an electrical resistance furnace of the type set forth, wherein a portion of a side wall defining the sealed enclosure is provided with a charging tube extending downwardly and inwardly to a point over the crucible, and means are provided for closing the charging tube allowing pressurizing of the enclosure.
  • the accompanying drawing shows diagrammatically an electrical resistance furnace which includes a tubular shield 1 composed of a metal which may be a heat resisting steel, such as a non-corrosive nickel-chrome steel, capable of working in the range of 800 to 1250 C.
  • a tubular shield 1 composed of a metal which may be a heat resisting steel, such as a non-corrosive nickel-chrome steel, capable of working in the range of 800 to 1250 C.
  • a crucible 2 preferably composed of silicon carbide, is supported within the shield 1 upon a bolster 3 of refractory material which rests upon a bed 4 of refractory material laid upon a bottom portion of an outer casing 5 of refractory material.
  • the shield 1 is provided at top and bottom with flanges 6 which engage refractory bricks 7 and 8 and further refractory bricks 9 are provided within the outer refractory casing 5.
  • the outer refractory casing 5 is enclosed by an outer steel casing 10 joined to a ring 11 secured t a top closure 12 so as to form a sealed enclosure containing the crucible, shield and refractory material.
  • An output tube 13 passing through the closure 12 is provided for extracting molten metal from the crucible 2 when pressure is introduced into the enclosure as hereinafter described.
  • the outside of the shield 1 is provided with a number of insulated supports 14 which carry heating elements 15 for heating the crucible through the shield 1.
  • the outer steel casing 10 is provided at the side with an emergency outlet in the form of zinc foil 16 clamped between an apertured plate 17 and flanges 18 adjacent an opening in the steel casing 10.
  • the foil 16 is sufliciently strong to withstand the pressure in the enclosure during casting (say 10-15 p.s.i.) but will melt should the crucible break or crack and discharge molten metal over the sloping surface of the bed 4 of refractory material onto the foil.
  • This emerency outlet is of great advantage since in the event of a crucible failure the bottom of the enclosure would otherwise retain the molten metal which, on solidifying, would be diflicult to remove.
  • thermocouple 19 is provided for monitoring the operating temperature in the region of the shield 1, with electrical connection to the heating elements being achieved by means of a terminal which passes from a protective cover 21 outside the steel casing 10, through the casing 10 a refractory material 5 and 9 to adjacent the heating elements 15.
  • the terminal consists of an electrically conducting rod 20 upon which is mounted an insulator 22 having a metallic cap 23.
  • the cap 23 is brazed to the rod 20 and the insulator 22 is bonded to a bush 24 mounted upon an insulated sleeve and screwed into the casing 10.
  • the furnace described above should be charged with molten metal, for example from a sustaining furnace, and then the metal discharged as and when required in a pressure casting process, under pressure through the tube 13.
  • the outer steel casing 10 is provided in its side wall above the level of the top of the crucible with an apertured steel plate 25, through which is passed a cast iron charging tube 26 extending downwardly towards the crucible, and having an integral flange 27 bolted to the plate 25, with the tube 26 extending inwardly through the refractory material 5 so that its inner end.overlies the crucible 2.
  • the tube 26 is closed by means of a closure member 28 carried on a screw-threaded clamp 29 mounted on a bracket 30.
  • the closure 28 is provided with a passageway 31 through which the interior of the enclosure may be pressurized.
  • the closure member 28 is withdrawn by undoing clamp 29 and a funnel (not shown) is rested in the bracket 30 to facilitate pouring of the molten metal through the tube 26 into the crucible 2.
  • a tube 32 composed of steel, such as one containing 25% nickel and 20% chromium.
  • An electrical resistance furnace including a wall means and cover defining a sealed enclosure, a crucible for molten metal supported within said sealed enclosure, means extending into the crucible for extracting the molten metal, when required for use, from the crucible under the influence of pressure or vacuum introduced into the sealed enclosure, a charging tube having inner and outer ends, said tube being positioned in an aperture in said wall means and said tube extending downwardly and inwardly into the enclosure to a point where the inner end of the tube is above and in communication with the interior of the crucible, a closure member operably connected to said wall means for closing the outer end of the charging tube and said closure member having a passageway extending therethrough and by means of which said passageway interior of the enclosure may be pressurized.
  • closure member operative connection comprises a clamp and a bracket for receiving and positioning a funnel to facilitate charging of the crucible when the closure member has been from the outer end of the tube.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
US682227A 1966-11-14 1967-11-13 Electrical resistance furnaces Expired - Lifetime US3431345A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB50977/66A GB1159829A (en) 1966-11-14 1966-11-14 Electrical Resistance Furnaces

Publications (1)

Publication Number Publication Date
US3431345A true US3431345A (en) 1969-03-04

Family

ID=10458157

Family Applications (1)

Application Number Title Priority Date Filing Date
US682227A Expired - Lifetime US3431345A (en) 1966-11-14 1967-11-13 Electrical resistance furnaces

Country Status (4)

Country Link
US (1) US3431345A (de)
BE (1) BE719125A (de)
DE (1) DE1583455B2 (de)
GB (1) GB1159829A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4238635A (en) * 1976-06-10 1980-12-09 Kalervo Lahtinen Melting and casting means
US6550526B1 (en) 1999-02-19 2003-04-22 Honsel Gmbh & Co., Kg Method and device for producing cast parts consisting of aluminium and magnesium alloys
US20070280328A1 (en) * 2006-05-30 2007-12-06 Howmet Corporation Melting method using graphite melting vessel
WO2008064485A1 (en) * 2006-11-29 2008-06-05 Ellis Frederick G A vertical electrically heated oven for baking coated parts

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1933851A (en) * 1931-03-13 1933-11-07 Bbc Brown Boveri & Cie Electric furnace
US2937789A (en) * 1953-10-16 1960-05-24 Ajax Magnethermic Corp Controlled metal dispensing

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1933851A (en) * 1931-03-13 1933-11-07 Bbc Brown Boveri & Cie Electric furnace
US2937789A (en) * 1953-10-16 1960-05-24 Ajax Magnethermic Corp Controlled metal dispensing

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4238635A (en) * 1976-06-10 1980-12-09 Kalervo Lahtinen Melting and casting means
US6550526B1 (en) 1999-02-19 2003-04-22 Honsel Gmbh & Co., Kg Method and device for producing cast parts consisting of aluminium and magnesium alloys
US20070280328A1 (en) * 2006-05-30 2007-12-06 Howmet Corporation Melting method using graphite melting vessel
WO2008064485A1 (en) * 2006-11-29 2008-06-05 Ellis Frederick G A vertical electrically heated oven for baking coated parts
CN101600927B (zh) * 2006-11-29 2012-10-03 费雷德里克·G·埃利斯 用于烘干涂敷零件的立式电加热炉

Also Published As

Publication number Publication date
DE1583455A1 (de) 1970-08-20
BE719125A (de) 1969-01-16
DE1583455B2 (de) 1971-12-30
GB1159829A (en) 1969-07-30

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