EP0005429B1 - Montage de contact électrique - Google Patents

Montage de contact électrique Download PDF

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Publication number
EP0005429B1
EP0005429B1 EP19780300834 EP78300834A EP0005429B1 EP 0005429 B1 EP0005429 B1 EP 0005429B1 EP 19780300834 EP19780300834 EP 19780300834 EP 78300834 A EP78300834 A EP 78300834A EP 0005429 B1 EP0005429 B1 EP 0005429B1
Authority
EP
European Patent Office
Prior art keywords
face
insert
electrode
graphite
contact assembly
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
Application number
EP19780300834
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German (de)
English (en)
Other versions
EP0005429A1 (fr
Inventor
Colin Frederick Widmer
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.)
James Brown and Sons Ltd
Original Assignee
James Brown and Sons 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 James Brown and Sons Ltd filed Critical James Brown and Sons Ltd
Publication of EP0005429A1 publication Critical patent/EP0005429A1/fr
Application granted granted Critical
Publication of EP0005429B1 publication Critical patent/EP0005429B1/fr
Expired legal-status Critical Current

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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
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/10—Mountings, supports, terminals or arrangements for feeding or guiding electrodes
    • H05B7/103—Mountings, supports or terminals with jaws
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
    • H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
    • H01R4/62—Connections between conductors of different materials; Connections between or with aluminium or steel-core aluminium conductors

Definitions

  • the present invention relates to contact assemblies for feeding electric current to electrodes in electric furnaces and seeks to provide a contact assembly which will given an adequate electrical contact between two conducting elements disposed in face to face relationship and which are clamped together or biassed towards each other by spring force or gravity or the like, the assembly permitting satisfactory passage of electricity and heat without demanding imprac- ticably fine tolerances in manufacture of the various parts.
  • Clamps for cylindrical graphite electrodes such as are used on an electric arc furnace, are normally made from cast or wrought copper and often include passages for water cooling.
  • electrode clamps including those shown in GB-A-693068 where a number of contact plates are pressed against the electrode by means of a closed flexible supporting ring and US-A-2834824 where hinged clamping bands are provided with pads to be clamped against the electrode.
  • the present practice is to provide the electrode clamp with two graphite pads to bridge the gap between the clamp and the coating of the electrode and thus to give the required electrical contact and carry the current between these conducting elements.
  • the pads take the form of inserts retained in dovetail grooves or slots in the face of the clamp.
  • a somewhat similar arrangement is shown in DE-C-545793, save that there is only one insert in the clamp.
  • GB-A-1185414 on the other hand provides a graphite pad which has chamfered upper and lower ends, so that the pad can be held by similarly shaped clamping members at these ends.
  • the graphite pads or inserts employ the inner and outer surfaces as the electrical and thermal contact areas.
  • the electrode is constituted by a steei biiiet. Electric current is fed to this billet through a stainless steel pad which is welded onto the top of a stainless steel bar which in turn is welded to the top of the billet.
  • the stainless steel pad is supported on a fork which carries the weight of the assembly and through which the vertical height can be controlled so that an arc is maintained on the bottom of the electrode.
  • a copper stub clamp is used which is shaped to form two- line contacts with the top face of the stainless steel pad and which is mechanically loaded with approximately nine tons to maintain the necessary electrical contact between the copper stub clamp and the steel pad and also to retain the pad securely on the fork.
  • the present invention inter alia, enables a more efficient system for electrical supply to both these different types of electrode.
  • a contact assembly for feeding electric current to an electrode in an electric furnace, the assembly comprising two conducting elements disposed face to face and clamped or pressed together and which are bridged by at least one graphite insert to carry the current, each insert being retained by a groove in the face of one of the conducting elements is characterized by a plurality of insert-receiving grooves in the face of one of the conducting elements, each groove having opposed side walls which converge away from the face, a separate graphite insert in each of the grooves, each insert being shaped to fit between the convergent walls of the groove, leaving one end of the insert spaced from the back of the groove and the opposite end of the insert protruding from the said face of the conducting element to make electrical contact with the face of the other of the conducting elements, the individual inserts being displaceable in their grooves independently of each other under the influence of the contact pressure, thereby to improve the electrical connection between the two conducting elements.
  • the wedge angle between the side walls of the grooves and of the graphite inserts should be such as to give sufficiently firm pressure between the graphite inserts and the sides of the groove on the one hand and the said other of the faces on the other hand to provide adequate electrical contact between these parts, whilst permitting slight movement of the inserts under pressure to take up any inaccuracies in the said other of the faces.
  • Fig. 5 of DE-C-429619 shows such a shape for a brush for the current collector of a commutator.
  • This document is concerned with the problem of reducing the friction between brushes and commutator in an electric machine and improving the mobility of the arm carrying the brushes.
  • the shape of the brushes is, in fact, immaterial and no indication, either explicit or implicit, is given as to any advantage gained by the use of a wedge-shaped brush either generally or for this particular application.
  • Fig. 1 shows a clamp of known type consisting of a copper cast body 10 provided with a bus tube connection 16 and having conduits 17 to lead water to and from water-cooling passages, which are not shown in this figure but may be the same as those illustrated in Fig. 2.
  • Two graphite pads 12 are held by top and bottom retaining plates 14 and lie within machined recesses in the body 10.
  • the rear face of each of the graphite pads 12 is plane, whereas the front face is curved to the radius equivalent to the radius of the electrode which is to be clamped and the two graphite pads when in position having a common axis for the radii of the curved surfaces.
  • the clamps illustrated are used with a clamping band to grip the cylindrical graphite electrodes; in other forms of construction more than one clamp may be arranged around the electrode with a suitable mechanism to cause the clamp segments to grip the electrode.
  • a suitable mechanism to cause the clamp segments to grip the electrode.
  • Figs. 2 and 3 show an electrode clamp according to the present invention.
  • the body 10 of the clamp is made from cast copper with the usual bus tube connection 16 and is provided with water passages 18, the construction of which will be well-known to those skilled in the art.
  • the body 10 is formed with ten longitudinal, vertical grooves 22 in its cylindrical electrode clamping face 20.
  • the side walls 24 of each groove are planar and form between them a small included angle so that each groove is a wedge-shaped recess.
  • a graphite insert 26 In each recess is placed a graphite insert 26, as shown in the upper part of Fig. 2.
  • Each insert seen in detail in Fig. 4, is similarly wedge-shaped to the grooves 22 with side faces 28 having the same included angle as the side walls 24 of the groove.
  • the rear face 30 can be planar and the front face 32 given a curved surface of the same radius as the outer surface of an electrode which is to be clamped. An outline of part of such an electrode is shown in broken lines at 34 in Fig. 2.
  • the ends 36 of the inserts are chamfered, so that the inserts can be held in position by a bottom retainer 38 made of nonmagnetic steel and upper aluminium bronze retainers 40.
  • the inserts 26 are comparatively loosely wedged in the wedge-shaped grooves 22.
  • clamping pressure is applied between the clamp shown in Fig. 2 and a clamping band on the other side which is not illustrated, the clamping pressure between the clamp and the electrode forces the inserts 26 into their respective grooves and creates good electrical contact on the one hand between the electrode and the inserts and between the inserts and the clamp.
  • top clamps 40 each comprising an aluminium bronze member which is cast with four inwardly directed fingers 42 and two inwardly directed flanges 44, 46 at the ends, these flanges having slots 48 which enable the retainer to be held in position under spring loading from headed bolts 50 screwed into the clamp body 10.
  • the included wedge angle between the side walls 24 of the grooves 22 and the side faces 28 of the inserts 26 should be sufficiently high to ensure the adequate contact which is required and sufficiently low to permit the slight movement which is necessary when the clamping is effected.
  • the optimum angle might well differ as between the grooves which are nearer the centre of the clamp and those which are nearer the two ends, since any movement of the clamp towards the electrode will cause greater movement of the central insert than those at the ends.
  • the effect of the wedge-shaped inserts is to provide a large contact surface with the electrode where the larger front faces 32 of the inserts contact the outer periphery of the electrode.
  • the clamp which is shown in the drawings could be made with a smaller number of larger inserts or a larger number of smaller inserts. Where there are a large number of inserts it may even be found unnecessary to form the front surfaces with a cylindrical surface.
  • Fig. 5 shows the upper end 52 of a stainless steel bar which is welded to the top of the steel billet (not shown) which becomes an electrode in the electro slag refining process.
  • a stainless steel pad 54 which is 50 mm in height, 356 mm in length and 240 mm in breadth.
  • Four wedge-shaped grooves 58 are located lengthwise through the upper face 56 of the bar 54 and in each of these grooves is a wedge-shaped insert 60.
  • the inserts 60 have their lower end spaced from the end of the groove and the upper end proud of the face 56 as seen in Fig. 5.
  • the electric supply is from a stub clamp the underface of which is flat (this stub clamp being indicated as 62 in chain lines in the drawings) and in consequence the upper end of each insert 60 presents a flat face to register with the flat bottom face of the stub clamp.
  • this stub clamp being indicated as 62 in chain lines in the drawings
  • the upper end of each insert 60 presents a flat face to register with the flat bottom face of the stub clamp.

Claims (8)

1. Montage de contact pour appliquer du courant électrique à une électrode dans un four électrique, le montage comprenant deux éléments conducteurs disposés face à face et serrés ou pressés ensemble et qui sont reliés par au moins une pièce d'insertion en graphite pour transporter le courant, chaque pièce d'insertion étant retenue par une gorge dans la face de l'un des éléments conducteurs, caractérisé par un certain nombre de gorges de réception d'insertion dans la face de l'un des éléments conducteurs, chaque gorge ayant des parois latérales opposées qui convergent en s'éloignant de la face, une pièce séparée d'insertion en graphite dans chacune des gorges, chaque pièce d'insertion étant configurée pour s'adapter entre les parois convergentes de la gorge, laissant une extrémité de la pièce d'insertion espacée du fond de la gorge et l'extrémité opposée de la pièce d'insertion faisant saillie de ladite face de l'élément conducteur pour former un contact électrique avec la face de l'autre des éléments conducteurs, les pièces individuelles d'insertion pouvant être déplacées dans leurs gorges, indépendemment les unes des autres sous l'influence de la pression de contact, pour ainsi améliorer la connexion électrique entre les deux éléments conducteurs.
2. Montage de contact selon la revendication 1 ayant.au moins quatre pièces d'insertion en graphite.
3. Montage de contact selon la revendication 1 ou la revendication 2 où les parois latérales des gorges sont sensiblement planes et ont un angle de coin tel que cela produise une pression suffisamment ferme entre les pièces d'insertion en graphite et les parois convergentes de la gorge d'une part, et ladite autre des faces d'autre part, pour produire un contact électrique adéquat entre ces pièces, tout en permettant un léger mouvement des pièces d'insertion sous pression pour compenser toute imprécision de ladite autre des faces.
4. Montage de contact selon la revendication 3 où ledit angle de coin est d'environ 14°.
5. Montage de contact selon l'une quelconque des revendications précédentes, où les deux éléments conducteurs sont le corps courbé d'une pince et la surface arrondie d'une électrode maintenue par le pince.
6. Montage de contact selon la revendication 6 où l'électrode est une électrode cylindrique en graphite.
7. Montage de contact selon la revendication 6 où le graphite est enrobé d'aluminium.
8. Montage de contact selon l'une quelconque des revendications 1 à 4 où les deux éléments conducteurs sont un élément de contact attaché à une billette d'acier formant une électrode et une pince sollicitée vers ledit élément de contact.
EP19780300834 1978-05-16 1978-12-15 Montage de contact électrique Expired EP0005429B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB1996078 1978-05-16
GB1996078 1978-05-16
GB7844761 1978-11-16
GB4476178 1978-11-16

Publications (2)

Publication Number Publication Date
EP0005429A1 EP0005429A1 (fr) 1979-11-28
EP0005429B1 true EP0005429B1 (fr) 1985-05-02

Family

ID=26254339

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19780300834 Expired EP0005429B1 (fr) 1978-05-16 1978-12-15 Montage de contact électrique

Country Status (5)

Country Link
EP (1) EP0005429B1 (fr)
BR (1) BR7902982A (fr)
CA (1) CA1108681A (fr)
DE (1) DE2862464D1 (fr)
MX (1) MX145683A (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2104183A1 (fr) * 2008-03-18 2009-09-23 ABB Schweiz AG Dispositif de raccordement électrique et raccord

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE545793C (de) * 1932-03-05 Norske Elektrokemisk Ind As Stromzufuehrung fuer Dauerelektroden
DE429619C (de) * 1920-08-15 1926-05-31 Siemens Schuckertwerke G M B H Buerstenhalter mit unter Federkraft stehendem, schwingendem Tragarm
CH99868A (fr) * 1922-06-13 1923-07-16 Friderich Louis Dispositif de connexion entre une électrode mobile de four électrique de grande puissance et la source d'énergie électrique alimentant le four.
GB693068A (en) * 1950-04-03 1953-06-24 Stickstoffdunger Ag F Improvements relating to electrode holding devices for electrothermic melting furnaces
US2834824A (en) * 1957-05-27 1958-05-13 Ohio Ferro Alloys Corp Automatic electrode clamping device
DE1758294C3 (de) * 1968-05-08 1979-08-02 Metalurgitschen Zavod Lenin, Pernik (Bulgarien) Elektrodenfassung für Kohlenstoffelektroden von Lichtbogenöfen

Also Published As

Publication number Publication date
EP0005429A1 (fr) 1979-11-28
BR7902982A (pt) 1979-11-27
DE2862464D1 (en) 1985-06-05
CA1108681A (fr) 1981-09-08
MX145683A (es) 1982-03-22

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