US3700224A - Melting furnace - Google Patents

Melting furnace Download PDF

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Publication number
US3700224A
US3700224A US865856A US3700224DA US3700224A US 3700224 A US3700224 A US 3700224A US 865856 A US865856 A US 865856A US 3700224D A US3700224D A US 3700224DA US 3700224 A US3700224 A US 3700224A
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US
United States
Prior art keywords
furnace
heating elements
wall
melting chamber
roof
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
US865856A
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English (en)
Inventor
Peter Nolting
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.)
Vereinigte Aluminium Werke AG
Original Assignee
Vereinigte Aluminium Werke AG
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Filing date
Publication date
Application filed by Vereinigte Aluminium Werke AG filed Critical Vereinigte Aluminium Werke AG
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Publication of US3700224A publication Critical patent/US3700224A/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
    • H05B3/00—Ohmic-resistance heating
    • H05B3/62—Heating elements specially adapted for furnaces
    • H05B3/66—Supports or mountings for heaters on or in the wall or roof
    • 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
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S266/00—Metallurgical apparatus
    • Y10S266/90—Metal melting furnaces, e.g. cupola type

Definitions

  • the electric heating resistances have [56] References Cited UNITED STATES PATENTS major and minor surfaces and are positioned so that their major surfaces extend parallel with the vertical plane of the melting chamber.
  • the present invention in general relates to a metallurgic resistance furnace and more in particular relates to a smelting furnace of the hearth-type in which the heating resistors are arranged in the melting chamber of the furnace.
  • hearth-type or reverberatory furnaces in which the heat is produced electrically and which are used for the metallurgic processing of, for example, aluminum or other type metals. It is conventional with such type furnaces that the electric heating elements or resistors are located beneath the hearth and that they transform their energy into heat radiation to which the charge being melted or processed in the furnace is subjected.
  • the temperature of the element or resistor can be maintained the lower during operation thereof, the better the element or resistor is capable of dissipating its heat to any direction surrounding it.
  • Certain known hearth-type furnaces employ heating elements which are freely suspended in the melting chamber of the furnace and consist of double coiled wire resistances. Such type heating elements have a favorable low operating temperature and an acceptable heat dissipation. However, such freely suspended elements, as will be self-evident, are subject to a direct spattering attack by the material which is processed.
  • Hearth-type furnaces utilize zig-zag type heating elements which are inserted in slotted stones.
  • Such type heating elements have a poor mechanical rigidness and are operated at a high temperature which is a disadvantage but, at the same time, such elements are less subjected to spattering of the material processed.
  • Object of the invention is to provide a furnace which positively overcomes the above disadvantages and which is simple as regards its construction and offers a great economy as regards its maintenance.
  • Such a furnace comprises a melting chamber enclosed by a wall and in which a plurality of spaced heating elements are transversely mounted in the upper region thereof, with the elements secured to opposite wall portions of the chamber.
  • the elements have major and minor surfaces and are positioned such that their major surfaces extend substantially parallel with the vertical plane of the melting chamber.
  • FIG. 1 shows a top plan view of the meltingfurnace according to the present invention
  • FIG. 2 is a cross-sectional view of the melting furnace taken along the line I-I. of FIG. 1;
  • FIG. 3 is a side view of a heating element incorporated in the furnace of FIG. 1 and illustrating, in part, the manner of suspending this element in the furnace;
  • FIG. 4 is a cross-sectional view of a heating element taken along the line II-II of FIG. 3;
  • FIG. 5 is a top view of the arrangement shown in FIG. 3;
  • FIG. 6 is a further side view of the heating element of FIG. 3 and illustrating the manner of connecting one end thereof to the inner furnace wall;
  • FIG. 7 is a top view of the arrangement of FIG. 6;
  • FIG. 8 illustrates. the heating element of FIG. 3, mounted in the furnace
  • FIG. 9 is a top view of the arrangement of FIG. 8.
  • FIG. 10 appearing on the sheet incorporating FIGS.
  • FIG. 1 and 2 illustrates, in part, the manner in which the heating element of FIG. 3 is suspended from the top of the furnace.
  • FIGS. 1 and 2 illustrate a melting furnace l which includes a melting chamber 2 enclosed by a wall 3.
  • a door arrangement 4 operative to admit material to be processed into the melting chamber 2.
  • the heating elements 8 are substantially straight, and as shown in FIG. 4, have a T-shaped cross section with major and minor surfaces 9 and 10, respectively.
  • the height of the major surfaces 9 of the heating elements 8 is substantially greater than the width of the minor surfaces 10 of the elements, and the latter are mounted in such a way in the melting furnace 1, that their major surfaces 9 extend substantially parallel with the vertical axis of the furnace 1 while their minor surfaces 10 extend substantially parallel with the horizontal axis of the furnace 1.
  • the heating elements 8 are positioned transversely relative to the elongation of the melting furnace.
  • Each two adjacent electric heating elements 8 at their respective outer ends, are pair-wise interconnected by means of band-shaped electric cross connectors l1 and thus formed into an electrically serieswound group 12. Shown in straight lines in FIG. 1, at the left-hand side thereof, is such a pair of interconnected heating elements 8. The rest of these interconnected elements 8 are shown in broken lines.
  • the electric heating elements 8 are operated by an AC- current and, in order to constitute a symmetric loading of the three phases R, S, T of the AC-power system, the elements 8 are formed into three electrically serieswound groups 12.
  • the cross connectors 11 at one side of the heating elements 8 are slightly spaced from the inner wall portion 6, inwards of the outer ends 13 of the elements 8 such that these outer ends 13 extend beyond the cross connectors 11.
  • a plurality of recesses 14 Formed in wall portion 6 are a plurality of recesses 14 in which the outer ends 13 of the heating elements 8 are received.
  • these recesses 14 in the wall 6 extend parallel and spaced relative to each other and transversely relative to the elongation of the melting chamber 2.
  • the outer ends 13 Upon insertion of the outer ends 13 into the recesses 14, the latter are stuffed with insulation stones and mineral wool, not shown, in order to obtain a better thermal insulation.
  • the opposite wall portion 7 is formed with an equal number of recesses 15 which extend substantially axially with the recesses 14in wall portion 6.
  • the recesses 15 are arranged to fixedly mount a plurality of supporting projections 16 whose number equals that of the electric heating elements 8.
  • the supporting projections 16 made of a non-scaling material, are formed with indentations 17 at their upper edge 16a, FIG. 6, in which the outer end portions 18, FIG. 7, of cylindrical or round bolts 19 are snugly but removably fitted.
  • the cylindrical bolts 19 are welded to the end portions 20 of the electric heating elements 3 and are attached thereto in such a way that they replace a portion of the major surfaces 9 at these end portions 20 of the heating elements 8, FIG. 6.
  • the cross connectors 11, at this side of the heating elements 8, are secured to the end portions 20 thereof, adjacent the bolts 19 and are of such a length that they interfit between each two inner opposing major surfaces 9 of each two adjacent heating elements 8, FIGS. 7 and 9, while the outer end portions 18 are longer than the cross connectors 1 1 and extend laterally outwardly beyond each two minor surfaces of each two adjacent heating elements 8, FIGS. '7 and 9.
  • the supporting projections 16 Upon insertion of the supporting projections 16 into the recesses 15, the latter are stuffed with insulation stones to obtain a better thermal insulation and to prevent tilting of the supporting projections'16 therein.
  • the discrete electric heating elements 8 are preferably suspended in spaced relationship of about 20 inches relative to each other by means of the suspension members 21.
  • This means that also the recesses 14 and 15 in the walls 6 and 7, respectively, are spaced about 20 inches apart relative to each other.
  • the suspension members 21, made of heat-resisting rods, at their lower ends are flat-forged and are key-wise inserted with these ends into slotted holes 22 arranged centrally in the minor surfaces 10 midway of the heating elements 8, FIGS. 3 and 5, and by rotation through 90 in holes 22, are fittedly secured against removal therefrom.
  • suspension members 21 are run through guide tubes 23 which extend through the top 24 of the melting furnace 1.
  • the upper projecting ends 21a of the member 21 are locked in position by means of split pins 25 which abut against profrilated bricks 26, supported on the steel housing 27 of the upper furnace surface.
  • the weight of the heating elements is not suspended from the inner surface of the furnace top 24, which has the advantage that a more rigid and reliable suspension is obtained while, in addition, with this manner of suspension, contact between the heating elements 8 and the steel housing 27 is avoided.
  • each group of series-wound heating elements 12 is connected with the secondary of a transformer 28 via terminal connectors 29 and guiderails 30 while the primary of the transformer is connected with an AC-power system, not shown.
  • the large cross-sectional area of the discrete electric heating elements effects a low electric resistance per mm, which enables that the heating elements can be advantageously operated at a low voltage and high amperage.
  • the electric heating elements 8, the electric cross connectors 11 and the terminal connectors 29 preferably are welded to each other while the terminal connectors 29, the guide-rails 30 and the terminal clamps of the transformers 28 are threadably connected to each other by means of screw members.
  • a wall furnace comprising a bottom wall, side walls and a roof defining a melting chamber of an uninterrupted space between said bottom wall and said roof adapted to receive in a lower part of said space a mass of molten material; heating means in said melting chamber for heating the interior thereof and comprising a plurality of spaced heating elements of uniform cross section throughout their length and extending in an upper region of said space transversely between opposite side walls, each of said heating elements having a T-shaped cross section comprising an upper horizontally extending portion and a narrow web portion extending vertically downwardly midway between opposite ends of said horizontally extending portion and having a height considerably greater than the width of said horizontally extending portion to thus reduce the surface areas of said heating elements which are subjected to spattering of molten material in the lower part of said space while improving the bending resistance of said heating elements; and means securing each of said plurality of heating elements to opposite side walls of said melting furnace.
  • said melting chamber is elongated and said side walls include a first wall and a second wall extending in the direction of elongation of said melting chamber, and wherein said securing means includes a plurality of recesses formed in said first wall and said second wall and operative to connect said T-shaped heating elements at opposite end portions thereof to said first and second walls.
  • T- shaped heating elements with one of said opposite end portions thereof is fixedly mounted in said recesses in said first wall
  • said securing means further includes a plurality of supporting members fixedly mounted in said recesses in said second wall and supporting said T-shaped heating elements at the second end ortion thereof;
  • each of said spaced heating elements is suspended by at least one of said rod-shaped suspension members.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Details (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
US865856A 1968-11-08 1969-10-13 Melting furnace Expired - Lifetime US3700224A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681807843 DE1807843B1 (de) 1968-11-08 1968-11-08 Widerstandsbeheizter metallurgischer Schmelzofen,insbesondere Herdschmelzofen

Publications (1)

Publication Number Publication Date
US3700224A true US3700224A (en) 1972-10-24

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ID=5712798

Family Applications (1)

Application Number Title Priority Date Filing Date
US865856A Expired - Lifetime US3700224A (en) 1968-11-08 1969-10-13 Melting furnace

Country Status (7)

Country Link
US (1) US3700224A (enrdf_load_stackoverflow)
AT (1) AT292325B (enrdf_load_stackoverflow)
CH (1) CH488983A (enrdf_load_stackoverflow)
DE (1) DE1807843B1 (enrdf_load_stackoverflow)
FR (1) FR2022843B1 (enrdf_load_stackoverflow)
GB (1) GB1245355A (enrdf_load_stackoverflow)
NO (1) NO125509B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2601586A1 (de) * 1975-01-17 1976-07-22 Schaefer Frank W Inc Aluminiumschmelzofen und -verfahren
US4353532A (en) * 1981-06-29 1982-10-12 Jay Dudley W Aluminum melting furnace
WO1986003282A1 (en) * 1984-11-19 1986-06-05 Noel Henry Wilson Carbon electrode electric furnace for smelting and refining ores
US4622678A (en) * 1984-07-05 1986-11-11 Electroglass Limited Electrically heated forehearth
US6537372B1 (en) * 1999-06-29 2003-03-25 American Crystal Technologies, Inc. Heater arrangement for crystal growth furnace
CN105937855A (zh) * 2016-07-11 2016-09-14 季国民 高压电保温加热炉

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB358884A (en) * 1930-07-04 1931-10-05 Alfred Smallwood Improvements in or relating to apparatus for generating radiating or transmitting heat created electrically
US1864334A (en) * 1927-03-10 1932-06-21 Electric Furnace Co Metallic resistor for electric furnaces
US2214123A (en) * 1936-09-11 1940-09-10 Saint Gobain Electrical furnace
US2323051A (en) * 1938-05-20 1943-06-29 Junker Otto Electric furnace
US2697127A (en) * 1954-12-14 poland
US2745891A (en) * 1954-03-15 1956-05-15 Rem Cru Titanium Inc Apparatus for melting highly reactive metals

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE706757C (de) * 1936-09-11 1941-06-05 Saint Gobain Elektrisch beheizter Strahlungsofen

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2697127A (en) * 1954-12-14 poland
US1864334A (en) * 1927-03-10 1932-06-21 Electric Furnace Co Metallic resistor for electric furnaces
GB358884A (en) * 1930-07-04 1931-10-05 Alfred Smallwood Improvements in or relating to apparatus for generating radiating or transmitting heat created electrically
US2214123A (en) * 1936-09-11 1940-09-10 Saint Gobain Electrical furnace
US2323051A (en) * 1938-05-20 1943-06-29 Junker Otto Electric furnace
US2745891A (en) * 1954-03-15 1956-05-15 Rem Cru Titanium Inc Apparatus for melting highly reactive metals

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2601586A1 (de) * 1975-01-17 1976-07-22 Schaefer Frank W Inc Aluminiumschmelzofen und -verfahren
US4353532A (en) * 1981-06-29 1982-10-12 Jay Dudley W Aluminum melting furnace
US4622678A (en) * 1984-07-05 1986-11-11 Electroglass Limited Electrically heated forehearth
WO1986003282A1 (en) * 1984-11-19 1986-06-05 Noel Henry Wilson Carbon electrode electric furnace for smelting and refining ores
US6537372B1 (en) * 1999-06-29 2003-03-25 American Crystal Technologies, Inc. Heater arrangement for crystal growth furnace
CN105937855A (zh) * 2016-07-11 2016-09-14 季国民 高压电保温加热炉
CN105937855B (zh) * 2016-07-11 2018-03-27 季国民 高压电保温加热炉

Also Published As

Publication number Publication date
GB1245355A (en) 1971-09-08
DE1807843B1 (de) 1970-07-30
FR2022843A1 (enrdf_load_stackoverflow) 1970-08-07
AT292325B (de) 1971-08-25
FR2022843B1 (enrdf_load_stackoverflow) 1973-03-16
NO125509B (enrdf_load_stackoverflow) 1972-09-18
CH488983A (de) 1970-04-15

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