EP0145219A1 - Assemblage d'électrode pour fours électriques à arc - Google Patents

Assemblage d'électrode pour fours électriques à arc Download PDF

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Publication number
EP0145219A1
EP0145219A1 EP84307459A EP84307459A EP0145219A1 EP 0145219 A1 EP0145219 A1 EP 0145219A1 EP 84307459 A EP84307459 A EP 84307459A EP 84307459 A EP84307459 A EP 84307459A EP 0145219 A1 EP0145219 A1 EP 0145219A1
Authority
EP
European Patent Office
Prior art keywords
electrode
sleeve
furnace
electrode assembly
seal
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.)
Granted
Application number
EP84307459A
Other languages
German (de)
English (en)
Other versions
EP0145219B1 (fr
Inventor
Kurt A. Strobele
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.)
Hatch Associates Ltd
Original Assignee
Hatch Associates 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 Hatch Associates Ltd filed Critical Hatch Associates Ltd
Priority to AT84307459T priority Critical patent/ATE41582T1/de
Publication of EP0145219A1 publication Critical patent/EP0145219A1/fr
Application granted granted Critical
Publication of EP0145219B1 publication Critical patent/EP0145219B1/fr
Expired legal-status Critical Current

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Classifications

    • 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
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/12—Arrangements for cooling, sealing or protecting electrodes
    • 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
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/10—Mountings, supports, terminals or arrangements for feeding or guiding electrodes

Definitions

  • This invention relates to improvements in electrode assemblies for electric arc furnaces, particularly but not exclusively arc furnaces used for steel making.
  • the second approach has been to seek reduction of heating of the electrode.
  • Numerous proposals have been made for fluid (usually water) cooled electrode structures, which reduce the length of graphite electrodes required. Examples may be found in United States Patents Nos. 4,121,042 and 4,168,392 (Prenn), 4,287,381 (Montgomery), French Patent No. 1,418,153 referred to above and French Patent Publications Nos. 2,176,546 and 2,222,821 (IRSID), German Patent Publication No. 2430817 (Sigri), British Patent Specification No.1,223,162 (Ostberg) and Belgian Patent No. 867,876 (Korf-Stahl AG).
  • the sleeve in order to achieve the object of the invention, the sleeve must extend close to the tip of the electrode. This is not ,practicable in many applications because of the risk that the sleeve will be damaged or destroyed by arcing from the furnace charge.
  • An alternative approach is found described in U. K. Patent Specification No. 2,000947A (Korf-Stahl AG) in which a water cooled jacket is provided around the electrode so as to shroud and support the entire electrode apart from the tip. In order to protect the jacket from arcing, it is insulated from the electrode, and provided with a refractory cladding. Additionally, an arc control magnet must be provided so as further to reduce the risk of arcing.
  • the sleeve is supported from an electrode support arm which supports the electrode through a drive mechanism which also must maintain insulation between the electrode and the arm, a separate electrical connection being made to the electrode. It is suggested that the sleeve might be supported from a conductive electrode clamp, but in this case some arrangement would be necessary to isolate the sleeve electrically from the clamp. In order to maintain insulation between the sleeve and the electrode it is necessary to provide guides for the electrode within the lower part of the sleeve in a vulnerable position near the tip of the electrode.
  • the assembly further includes means for defining a passageway for the electrode through a roof of the furnace, , the vertical extent of the sleeve being such that it will extend into the passageway throughout the normal range of movement of the assembly.
  • This provides some degree of restriction of the gap through which gases may pass around the electrode, and provides some shielding of the roof structure.
  • no additional load is applied to the furnace roof, and the arrangement is well adapted to the provision of a more effective electrode seal.
  • a sliding annular seal acting between the sleeve and the passageway defining means when the sleeve extends into the latter.
  • the seal is retained for axial sliding movement on the external surface of the sleeve.
  • the seal is retained by the passageway defining means and defines a tapered top entrance thereto for the bottom end of the sleeve.
  • the furnace 2 has a roof 4, and a refractory lining 6 for containing a charge which may have a maximum melt level 8.
  • Means (not shown) are provided for swinging the roof 4 and electrode assemblies relative to the furnace, for example so that a fresh charge may be introduced.
  • electrode assemblies 10 must be raised to a level such that the lower tips 12 of electrodes 14 will clear the remainder of the furnace structure.
  • the electrodes shown are conventional consumable electrodes, formed by connecting standard electrode elements 16 end to end in vertical alignment.
  • the electrodes pass through conventional electrode clamps 18 which releasably support the electrodes so that the string of electrode elements can be moved through the clamp to compensate for the erosion which occurs at tip 12 as the electrode is consumed.
  • Each clamp also served to conduct current to the respective electrode. Particularly during the early stages of a melt, a substantial degree of up and down movement of electrodes may be necessary as an arc is struck and a desired current level maintained, and a further range of movement is necessary to accommodate erosion of the electrode between successive adjustments of the clamps 18.
  • the clamps are supported, by means not shown, so as to provide this normal operating range of movement, together with the additional range of upward movement required when the roof of the furnace is to be swung as described above.
  • the electrodes pass through apertures 20 in a central electrically insulative portion 22 of the furnace roof. Although only two electrodes are actually shown in Figure 1, there will normally be a group of three symmetrically placed electrodes, one for each phase of a three phase current supply.
  • each electrode clamp supports a depending water cooled sleeve 24 which surrounds the portion of the electrode 14 beneath the clamp 18.
  • the sleeve is supported from the electrode clamps by bolts 26, and a seal 28 is provided to prevent a through flow of gas between the sleeve and the electrode.
  • the sleeve has water inlet and outlet connections 30 (only one is shown), and internal ribs 32 to strengthen the sleeve and guide the flow of water or alternative cooling fluid within the sleeve to provide effective cooling of the latter.
  • the sleeve is preferably fabricated from non-magnetic stainless steel in order to resist corrosion and magnetically induced eddy currents.
  • the vertical extent of the sleeve is such that during normal operation of the furnace, i.e. except during charging and initial start-up, it will at all times extend into the opening 20, as extended in this instance by a water cooled annulus 34 which is supplied with cooling water through connections 36 (again only one is shown).
  • the annulus may also be fabricated from non-magnetic stainless steel.
  • the lower end of the sleeve ends well short of the lower end of the electrode.
  • the extent of the sleeve should be such that it will never extend down to arcing proximity of a level at which conductive material is found in the furnace. This level will be above the maximum melt level 8 in the furnace by an amount depending on how "quietly" the furnace operates and the nature of the furnace charge. For example, in a furnace used for melting steel scrap, unmolten metallic material could contact the electrode substantially above the melt level, and the same could occur in other operations in which there is violent activity within the furnace.
  • the sleeve is dimensioned so that it is loose on the electrode and preferably spaced from it so that it will not obstruct longitudinal movement of the electrode 14 through the clamp 18, it will shroud the electrode sufficiently to eliminate any substantial sidewall oxidation of the electrode within the sleeve, and will provide significant cooling of this portion of the electrode. Even without the sealing arrangement to be described below, the sleeve will also act to restrict the flow of gases through the opening 20, and will shield the electrode from this flow.
  • a metallic sealing ring 40 rests on a seating formed by the annulus 34 and supports a high temperature seal element 42, for example of silica fibre, in sliding contact with the outer surface of the sleeve 24, so as to maintain a substantially gas-tight seal throughout the normal range of movement of the electrodes, this range being illustrated by the electrode assemblies shown on the right and left hand sides respectively of Figures 1 and 2.
  • the annulus 34 not only provides a seating for the ring 40, but also defines the opening 20 and protects the fabric of the furnace roof.
  • the sleeve In order to provide for additional upward movement of the electrode, the sleeve is provided with a lip 44 at its lower end, which engages the sealing ring 40 and lifts it clear of the annulus 34 as shown in Figure 3.
  • the loss of sealing at this stage is not important, since it will usually occur only during short parts of the furnace operating cycle.
  • the ability of the sealing ring 40 to lift from the annulus 34 will also prevent the seal 42 from being damaged should foreign matter adhere to the exterior of the sleeve 24.
  • annulus 34 may be desirable to extend vertically to provide arrangements such as those shown in Figures 4, 5 and 6.
  • the annulus 34 is replaced by a water cooled sleeve in portions 46 and 48.
  • the portion 46 extends through the opening 20, and defines a passageway sufficiently long to shroud the sleeve 24 even when the latter is in its lowermost position.
  • the external surface of the portion 46 of the sleeve extending into the furnace has a refractory coating 50.
  • the portion 48 provides an upward extension of the opening 20 which reduces the extent to which the sleeve 24 needs to project within the furnace.
  • the arrangement of Figures 4 and 5 has the disadvantage that it applies additional loading to the furnace roof, and the simplified arrangements using an annulus 34, or a shorter sleeve 52 as shown in Figure 6, will often be adequate.
  • seal 54 which remains captive on the upper portion 56 of two water cooled sleeve portions 56, 58 defining the passage 20 through the furnace roof.
  • the seal comprises an annular seal member 60 defining a frusto-conical passage, the narrow end of which will just pass the sleeve 24.
  • the seal member rests on an annular bearing pad 62 within a holder 64, within which the seal member is urged towards a centred position by locating pins 66 and springs 68.
  • the sleeve 24, which in this case lacks a lip 44, can withdraw from the member 60 when it is desired to lift the electrodes beyond their normal range of movement.
  • a seal assembly is mounted on the annulus 34 (see Figures 1 and 2), and comprises a plurality of hinged segments 70 (only one is shown), connected by hinges 72 to a mounting ring 74 supported on the annulus 34.
  • Each segment carries at its inner end a graphite sealing element 76 which is urged inwardly and upwardly towards the sleeve 24 by a counterweight 80 at the outer end of the segment.
  • the sealing element can, because of its hinged mounting, ride over obstructions on the surface of the sleeve 24 as the.electrode moves up and down.
  • the geometry of the arrangement precludes a perfect seal as the segments hinge independently, but a large measure of control can nevertheless be exercised over gas flow into or out of the furnace.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)
  • Discharge Heating (AREA)
EP84307459A 1983-10-31 1984-10-30 Assemblage d'électrode pour fours électriques à arc Expired EP0145219B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84307459T ATE41582T1 (de) 1983-10-31 1984-10-30 Elektrodenvorrichtung fuer elektrische lichtbogenoefen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US54747483A 1983-10-31 1983-10-31
US547474 1983-10-31

Publications (2)

Publication Number Publication Date
EP0145219A1 true EP0145219A1 (fr) 1985-06-19
EP0145219B1 EP0145219B1 (fr) 1989-03-15

Family

ID=24184776

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84307459A Expired EP0145219B1 (fr) 1983-10-31 1984-10-30 Assemblage d'électrode pour fours électriques à arc

Country Status (4)

Country Link
EP (1) EP0145219B1 (fr)
AT (1) ATE41582T1 (fr)
CA (1) CA1268200A (fr)
DE (1) DE3477336D1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002071811A3 (fr) * 2001-03-02 2002-11-14 Hatch Ass Ltd Garniture d'etancheite pour four a arc
KR100648614B1 (ko) 2005-12-09 2006-11-23 주식회사 포스코 전극봉 절손 방지 기능을 갖는 전극봉 클램핑 장치
CN110657664A (zh) * 2019-11-04 2020-01-07 中冶赛迪工程技术股份有限公司 一种废钢预热密封装置及电弧炉
CN114087870A (zh) * 2021-12-28 2022-02-25 无锡博众热能环保设备有限公司 一种高硅硅锰合金密闭矿热炉
CN115506033A (zh) * 2022-09-28 2022-12-23 乌海市京运通新材料科技有限公司 一种单晶炉热场对中结构及对中方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1690795A (en) * 1923-05-28 1928-11-06 Sagramoso Guido Electric furnace
US2551420A (en) * 1948-04-14 1951-05-01 Siemens Spa Italiana Gastight electrode seal
DE1030481B (de) * 1956-09-01 1958-05-22 Demag Elektrometallurgie Gmbh Elektroden-Tieffassung mit als Schutzmantel ausgebildetem Fassungszylinder
FR1174176A (fr) * 1956-04-13 1959-03-06 Sunrod Mfg Corp Mâchoire de serrage d'électrodes
US2979550A (en) * 1959-03-13 1961-04-11 Tennessee Products And Chemica Electrode seal
US3835233A (en) * 1973-12-07 1974-09-10 Canada Steel Co Electrode seals for electric-arc furnaces

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1690795A (en) * 1923-05-28 1928-11-06 Sagramoso Guido Electric furnace
US2551420A (en) * 1948-04-14 1951-05-01 Siemens Spa Italiana Gastight electrode seal
FR1174176A (fr) * 1956-04-13 1959-03-06 Sunrod Mfg Corp Mâchoire de serrage d'électrodes
DE1030481B (de) * 1956-09-01 1958-05-22 Demag Elektrometallurgie Gmbh Elektroden-Tieffassung mit als Schutzmantel ausgebildetem Fassungszylinder
US2979550A (en) * 1959-03-13 1961-04-11 Tennessee Products And Chemica Electrode seal
US3835233A (en) * 1973-12-07 1974-09-10 Canada Steel Co Electrode seals for electric-arc furnaces

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002071811A3 (fr) * 2001-03-02 2002-11-14 Hatch Ass Ltd Garniture d'etancheite pour four a arc
AU2002240739B2 (en) * 2001-03-02 2006-06-15 Hatch Ltd. Electrode seal for arc furnace
KR100648614B1 (ko) 2005-12-09 2006-11-23 주식회사 포스코 전극봉 절손 방지 기능을 갖는 전극봉 클램핑 장치
CN110657664A (zh) * 2019-11-04 2020-01-07 中冶赛迪工程技术股份有限公司 一种废钢预热密封装置及电弧炉
CN114087870A (zh) * 2021-12-28 2022-02-25 无锡博众热能环保设备有限公司 一种高硅硅锰合金密闭矿热炉
CN115506033A (zh) * 2022-09-28 2022-12-23 乌海市京运通新材料科技有限公司 一种单晶炉热场对中结构及对中方法

Also Published As

Publication number Publication date
DE3477336D1 (en) 1989-04-20
ATE41582T1 (de) 1989-04-15
CA1268200A (fr) 1990-04-24
EP0145219B1 (fr) 1989-03-15

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