DE102019217433A1 - Electrode holding device and system for repositioning an electrode in a metallurgical furnace - Google Patents

Abstract

The invention relates to an electrode holding device (10) comprising a housing (11) and a pressure piece (15) movably guided therein, the pressure piece (15) being movable against an electrode (1) with a predetermined clamping force. The housing (11) is designed in the form of an elongated box and has a vertically running through opening (12) through which the electrode (1) extends. The pressure piece (15) is arranged adjacent to the through opening (12) of the housing (11) and can only be moved from one side against the electrode (1) using a spring element (16) or a hydraulic cylinder (20) to exert a compressive force on the electrode (1) and thereby clamp the electrode (1) within the through opening (12) of the housing (11).

Description

The invention relates to an electrode holding device according to the preamble of claim 1, and a system for repositioning an electrode of a metallurgical furnace, in which two such electrode holding devices are arranged one above the other in the vertical direction.

According to the prior art, electrode holding devices are known in which the electrode is pulled against a current-transmitting contact jaw via a movable mounting ring. The required contact pressure on the mounting ring is always applied via a set of springs for reasons of safety. To loosen the mounting ring or the electrode, the spring assembly is hydraulically compressed in the opposite direction, i.e. opposite to the contact force.

In order to reduce maintenance work and the resulting downtimes of metallurgical furnaces, spring packs and hydraulic cylinders can be designed as a compact, removable unit in the aforementioned electrode holding devices. However, these units are difficult to access and difficult to reach with a crane. In addition, if necessary, they have to be detached or attached from the support arm head directly on site.

In the above-mentioned electrode holding devices, depending on the design, the forces required for holding or holding and releasing the electrode are transmitted via a thread. This pulls the movable mounting ring against the electrode. A disadvantage here is that if the force-transmitted shaft breaks, there is an immediate loss of the contact pressure against the electrode.

Another disadvantage of known electrode holding devices that are based on a pulling arrangement of the mounting ring is that small bending cross-sections of the mounting ring in the area of the integration into the support arm head, especially when using electrodes with a large diameter, lead to excessive bending and torsional stresses and corresponding deformations to lead. The same also applies to the support arm head, which is exposed to high bending loads in the area where the mounting ring is integrated.

Furthermore, the use of nipple robots is problematic because the movable mounting ring is poorly suited as a torque support when screwing on a new piece of electrode. In addition, the mounting ring may also have to absorb the weight of the nipple robot, as a result of additional bending and torsional loads, as already explained above.

Accordingly, the invention is based on the object of eliminating the disadvantages described above in relation to an electrode holding device.

This object is achieved by an electrode holding device with the features of claim 1 and by a system with the features specified in claim 15. Advantageous developments of the invention are defined in the dependent claims.

An electrode holding device according to the invention is used, in accordance with its name, to hold an electrode, in particular of a metallurgical furnace, for example an electric arc furnace (EAF) in steelworks. Such an electrode holding device comprises a housing and a pressure piece movably guided therein, wherein the pressure piece can be moved against the electrode with a predetermined clamping force. The housing is in the form of an elongated box and has a vertically extending through opening through which the electrode extends. The pressure piece is arranged adjacent to the through opening of the housing and can only be moved from one side against the electrode using a spring element or a hydraulic cylinder in order to exert a pressure force on the electrode and thereby clamp the electrode within the through opening of the housing.

The invention is based on the essential knowledge that the housing is box-shaped, i.e. in the form of an elongated box and that no movable electrode holding ring is provided therein through which the electrode would be passed. Instead, the housing has a vertically running through opening through which the electrode extends, the clamping of the electrode being achieved by the pressure piece which is only pressed from one side against the electrode using a spring element or a hydraulic cylinder. Such a design enables larger and more stable cross-sections than would otherwise be possible according to the prior art using a movable mounting ring. Consequently, mechanical stresses and the resulting deformations for the electrode holding device and its housing are significantly smaller, which is advantageous when using electrodes with a large diameter.

With the present invention, in relation to the arrangement of the contact or pressure surfaces for clamping the electrode, compared to the conventionally known ones mentioned at the beginning Electrode holding devices, a reversal realized. This means that with the present invention, in contrast to conventional clamping devices, a pressure piece is now pressed against the electrode string or the electrode and is not pulled. Such a reversed arrangement of the contact or pressure surfaces makes it possible to design the housing in a box construction without using a movable electrode holding ring, as is otherwise usual.

In an advantageous further development of the invention, the housing of the electrode holding device can be integrated into an electrode support arm head. For example, it is possible for the housing of the electrode holding device and the electrode support arm head to be formed in one piece with one another. One advantage here is that the housing is completely fixed and solidly connected to the electrode support arm head without there being any risk of the housing being accidentally detached.

According to an alternative development of the invention, it can be provided that the housing of the electrode holding device is detachably attached to an electrode support arm head. One advantage here is that the housing can be detached from the electrode support arm head if necessary, for example for maintenance and / or repair purposes.

In an advantageous development of the invention, a spring element, preferably in the form of a spring assembly, is arranged inside the housing. This spring element is in operative connection with a bolt connected to the pressure piece. As a result, a compressive force can be exerted on the pressure piece in the direction of the electrode by means of the spring element in order to thereby, as explained, clamp the electrode within the through opening of the housing.

In an advantageous development of the invention, an actuator (for example in the form of a hydraulic cylinder) is arranged or fastened within the housing, with which a force can be applied to the bolt that acts opposite to the force of the spring element or the spring assembly. By actuating this actuator, the clamping force of the spring element or the spring assembly can be canceled if the electrode is to be released. In order to achieve a compact embodiment of the invention, it is useful if this actuator is arranged between the pressure piece and the spring element or spring assembly. This can be made possible in that the actuator has a central through hole through which the bolt, which is in operative connection with the pressure piece, extends.

In an advantageous development of the invention, it can be provided that a hydraulic cylinder is provided, preferably in the form of a plunger cylinder, which is arranged inside the housing and is in operative connection with a bolt connected to the pressure piece to exert a pressure force on the pressure piece in the direction of the electrode. In this regard, it goes without saying that such a hydraulic or plunger cylinder performs the same function as the spring element or spring assembly, namely generating a compressive force on the pressure piece to move it in the direction of the electrode for the purpose of jamming the electrode within the through opening of the housing.

In the last-mentioned variant of the electrode holding device according to the invention, at least one return spring can be provided inside the housing, which acts on the bolt or the hydraulic cylinder. This return spring causes the pressure piece to be reset away from the electrode when the hydraulic cylinder is not actuated and it is accordingly desired to release the electrode.

In an advantageous further development of the invention, a current conduction can be provided for the electrode. This ensures that the electrode is appropriately supplied with current or energy when a metallurgical furnace is in operation.

For the aforementioned current conduction it can be provided that it comprises at least one element which consists of copper or aluminum or is at least coated with copper. This ensures a good current flow to the electrode, with low transmission losses. This element for conducting current can expediently be attached to an inner circumferential surface of the through opening of the housing, namely on a side opposite to the pressure piece.

A good current transmission for said current lead can be achieved in that the element of the current lead is formed from a copper strip, from a strip made of aluminum or from a copper-coated metal strip. With such an element it is ensured for the current conduction that current or energy is transmitted to the electrode jammed in the through opening of the housing.

Water cooling can expediently be provided for the housing of the electrode holding device according to the invention. This achieves the advantage that the operating temperature of the electrode holding device and the associated components which are arranged in the housing do not exceed a permissible value and in this respect in particular when used with a metallurgical furnace will not be damaged. Such a water cooling of the housing is particularly recommended for the case when the electrode holding device is equipped with a current conduction in order to transmit current or energy to the electrode.

In an advantageous further development of the invention, it can be provided that the housing is equipped with copper-clad sheet steel to conduct current for the electrode. Such a copper plating can run in the longitudinal direction of the housing or of the electrode support arm head and has the advantage that it enables a cost-effective implementation of a good transmission path with regard to current or energy to the electrode.

In an advantageous development of the invention, the housing of the electrode holding device can consist of aluminum or have parts made of aluminum. This leads to the advantage that the dead weight of the housing, for example in comparison to steel, is significantly lower, as a result of which the occurrence of bending loads on an electrode support arm is reduced.

In connection with the aforementioned current conduction, it is additionally pointed out that instead of copper, aluminum can also be used as the current-carrying element.

The electrode holding device according to the invention is also distinguished by the fact that, taking into account the aforementioned aspects, it can be designed in a modular design, based on the principle of a modular system. This also includes the fact that the electrode holding device according to the invention can be matched to different diameters of electrodes, so that electrode diameter-related series can be formed. With regard to such different series, in addition to interchangeability, it is also possible to reuse individual parts with one another. As a result, increased availability is achieved for the electrode holding device according to the invention, with reduced costs at the same time.

The invention also provides a system for repositioning an electrode of a metallurgical furnace. This system comprises two of the electrode holding devices already explained above, which are now arranged one above the other in the vertical direction. The system further comprises a back-up lifting mechanism, which consists of three hydraulic plunger cylinders, which are each attached to the lower electrode holding device, the piston rods of the plunger cylinders being connected to the upper electrode holding device.

In the above-mentioned system it can be provided that, on the one hand, two plunger cylinders of the post-set lifting mechanism are attached to the side of the through opening of the housing on which the pressure piece is provided. On the other hand, the third plunger cylinder is attached on the opposite side of the through opening opposite the pressure piece. As a result, a triangle is spanned in a horizontal plane with the three plunger cylinders of the lifting gear, within which the center of gravity of the electrode is located. This also ensures that the occurrence of bending loads and stresses is reduced when the adjustment hoist is in operation.

In an advantageous further development of the system according to the invention, the lower of the two electrode holding devices is equipped with a current lead, as has already been explained above. In contrast, the upper of the two electrode holding devices is not designed to carry current, the piston rods of the plunger cylinders being designed to be electrically insulated from the upper electrode holding device.

The present invention further provides that the electrode holding device according to the invention explained above can be used in an electrode maintenance stand which also has a screwing device and an electrode guide / centering device. Such an electrode maintenance stand serves, for example, as a “nipple device” and for the purpose of connecting two separate electrodes to one another at their end faces.

• - Aufbau der Elektrodenhaltevorrichtung ohne beweglichen Elektrodenfassungsring, d.h. ohne ziehende Kraftübertragung;
• - Infolgedessen geringere Biege- und Torsionsbelastung der Vorrichtung und keine Notwendigkeit tragender Gewinde oder entsprechender Bolzen;
• - Reduzierung von Kühlwasserkreisläufen;
• - Abnehm- und austauschbare Elektrodenhaltevorrichtungen ermöglichen Modulbauweise, bzw. ein Baukastensystem, bestehend aus verschiedenen Elektrodenhaltevorrichtungen;
• - Die Abnehmbarkeit ermöglicht es, z.B. eine defekte Elektrodenhaltevorrichtung anstatt eines ganzen Elektrodentragarms schnell und einfach auszutauschen und unter Werkstattbedingungen zu reparieren oder zu warten - dadurch bedingt ergeben sich kürzere Stillstandzeiten für den Ofenbetrieb;
• - Geringeres Kupfervolumen an den Kontaktbacken (Verschleißteil) - dies führt auch zu geringeren Herstellungskosten;
• - möglicher Einsatz bei einer Elektrodennachsetzvorrichtung, die nach dem Stand der Technik aus DE 10 2013 224 552 A1 bekannt ist;
• - Elektrodenhaltevorrichtungen in Kastenbauweise eignen sich direkt auch als Basis für Elektrodenannippelstände.

Further advantages of the invention result from the following aspects:

• Construction of the electrode holding device without a movable electrode holding ring, that is to say without a pulling force transmission;
• - As a result, less bending and torsional stress on the device and no need for load-bearing threads or corresponding bolts;
• - Reduction of cooling water circuits;
• - Removable and exchangeable electrode holding devices enable modular construction or a modular system consisting of various electrode holding devices;
• The removability makes it possible, for example, to replace a defective electrode holder instead of a whole electrode support arm quickly and easily and to repair or maintain it under workshop conditions - this results in shorter downtimes for furnace operation;
• - Lower copper volume on the contact jaws (wear part) - this also leads to lower manufacturing costs;
• - Possible use with an electrode positioning device that is made according to the prior art DE 10 2013 224 552 A1 is known;
• - Electrode holding devices in box design are also directly suitable as a basis for electrode nipple stands.

• 1 eine Querschnittsansicht durch eine Elektrodenhaltevorrichtung nach einer ersten erfindungsgemäßen Ausführungsform,
• 2 eine Draufsicht auf die Elektrodenhaltevorrichtung von 1,
• 3 eine Querschnittsansicht durch eine Elektrodenhaltevorrichtung nach einer zweiten erfindungsgemäßen Ausführungsform,
• 4 eine Draufsicht auf die Elektrodenhaltevorrichtung von 3,
• 5 eine vereinfachte Perspektivansicht der Elektrodenhaltevorrichtung von 1 bzw. von 3,
• 6 ein erfindungsgemäßes System zum Nachsetzen einer Elektrode eines metallurgischen Ofens, bei dem zwei erfindungsgemäße Elektrodenhaltevorrichtungen gemäß 1 oder gemäß 3 in vertikaler Richtung übereinander angeordnet sind und zwischen diesen Elektrodenhaltevorrichtungen ein Nachsetzhubwerk vorgesehen ist,
• 7 eine vereinfachte Draufsicht auf eine Elektrodenhaltevorrichtung beim Einsatz mit dem System gemäß 6, und
• 8 eine vereinfachte Ansicht eines Elektrodenwartungsstands, bei dem eine Elektrodenhaltevorrichtung gemäß 1-5 eingesetzt wird.

Preferred embodiments of the invention are described in detail below with reference to a schematically simplified drawing. Show it:

• 1 a cross-sectional view through an electrode holding device according to a first embodiment of the invention,
• 2 a plan view of the electrode holder of FIG 1 ,
• 3rd a cross-sectional view through an electrode holding device according to a second embodiment of the invention,
• 4th a plan view of the electrode holder of FIG 3rd ,
• 5 FIG. 3 is a simplified perspective view of the electrode holder of FIG 1 or from 3rd ,
• 6th a system according to the invention for repositioning an electrode of a metallurgical furnace, in which two electrode holding devices according to the invention according to 1 or according to 3rd are arranged one above the other in the vertical direction and a lifting mechanism is provided between these electrode holding devices,
• 7th a simplified plan view of an electrode holder when used with the system according to FIG 6th , and
• 8th a simplified view of an electrode maintenance stand in which an electrode holding device according to FIG 1-5 is used.

With reference to the 1 to 7th preferred embodiments of electrode holding devices 10 and a system equipped with it 100 for repositioning an electrode 1 of a metallurgical furnace (not shown) in accordance with the present invention. The same features in the drawing are each provided with the same reference numerals. At this point it is pointed out separately that the drawing is only shown in a simplified manner and in particular without a scale.

1 shows an electrode holding device according to the invention 10 according to a first embodiment in a cross-sectional view in connection with an electrode 1 , in which 2 a plan view of the electrode holder 10 of 1 (with electrode) shows.

In the same way, in 3rd an electrode holding device according to the invention 10 according to a second embodiment shown in a cross-sectional view, in connection with an electrode, wherein in 4th a plan view of the electrode holder 10 of 3rd (with electrode 1 ) is shown.

The electrode holder 10 includes a housing 11 , the part of an electrode support arm head 14th is. The case 11 is designed in the form of an elongated box. In the case 11 is a vertical through opening 12th (see. 2 , 4th ) is provided, which is, for example, octagonal, and in any case is larger with its inner diameter than an outer diameter of the electrode 1 .

As in 1 or. 3rd Illustrates can be an electrode 1 into the through opening 12th of the housing 11 be introduced so that the electrode 1 through the through opening 12th extends therethrough.

The case 11 is on an electrode support arm 2 (see. 2 , 4th ) and can be removed from this if necessary.

Inside the case 11 is adjacent to the through opening 12th a pressure piece 15th added, which in the direction of the through opening 12th or an electrode received therein 1 (and in the opposite direction, i.e. away from the through opening 12th ) is movable.

For the electrode holder 10 a power supply can be provided. In this case, the power supply includes an element 24 , that on or in the inner circumferential surface 13th the passage opening 12th is attached, namely on one of the pressure piece 15th opposite side. The element 24 can be made from a copper strip 25th or from a metal strip coated with copper.

For clamping the electrode 1 inside the through opening 12th of the housing 11 is on the pressure piece 15th exerted a compressive force, namely only from one side. As a result, the movable pressure piece 15th against the electrode 1 pressed in the drawing plane of the representation of 1 or. 3rd from right to left. The exertion of such a compressive force does not only result in the electrode being clamped or fixed 1 within the passage opening 12th achieved, but at the same time a close contact between the electrode 1 and the element 24 or the copper strip 25th , ensuring a good transfer of current or energy to the electrode 1 is guaranteed.

5 Figure 13 shows a perspective view of the electrode holder 10 of 1 or. 3rd if with it an electrode 1 in the through opening 12th of the housing 11 is clamped or held.

In the first embodiment of the electrode holding device according to the invention 10 according to 1 and 2 is inside the case 11 at least one spring element 16 added, preferably in the form of a spring package 17th . This spring package 17th is in operative connection with a bolt B ₁ , the one with the pressure piece 15th connected is. Thus, the preload of the spring assembly 17th over the bolt B ₁ on the pressure piece 15th transferred, as a result of which then the electrode 1 in the through opening 12th is jammed.

To release the clamp for the electrode 1 is in the embodiment of 1 an actuator 18th provided between the pressure piece 15th and the spring element 16 or the spring package 17th is arranged. This actuator 18th can be designed in the form of a hydraulic cylinder. The actuator expediently has 18th a central through hole 19th through which the bolt B ₁ extends therethrough. When the actuator is actuated 18th gets on the bolt B ₁ exerted a compressive force that is opposite to the force of the spring assembly 17th is aligned and the preload of the spring assembly 17th overcomes. Thus, the pressure piece 15th from an outer peripheral surface of the electrode 1 be withdrawn to clamp the electrode 1 inside the through opening 12th of the housing 11 to cancel.

For transferring the pressure force to the electrode 1 may be emphasized at this point that the bolt used for this purpose B ₁ completely without load-bearing threads or the like. This is due to the reverse arrangement of the contact or pressure surfaces for clamping the electrode compared to the prior art 1 possible, with the pressure piece as explained 15th only against the electrode from one side 1 is pressed.

With regard to the embodiment of the electrode holding device according to the invention 10 according to 1 or. 2 it is emphasized separately that this is used in particular as a readjusting device. This is due in particular to the spring package for safety reasons 17th whose preload is always via the bolt, as explained B ₁ on the pressure piece 15th is transferred to thereby the electrode 1 inside the through opening 12th to jam.

In the second embodiment of the electrode holding device according to the invention 10 according to 3rd and. 4th is used to hold or clamp the electrode 1 The required compressive force is not generated by a spring element or spring assembly, but by a hydraulic cylinder 20th generated, which can be designed for example in the form of a plunger cylinder. As evidenced by the representation of 3rd is this hydraulic cylinder 20th also inside the housing 11 recorded. To transfer the pressure force from the hydraulic cylinder 20th on the pressure piece 15th the hydraulic cylinder is standing 20th in operative connection with a bolt B ₂ , the one with the pressure piece 15th connected is.

By means of the hydraulic cylinder 20th can on the pressure piece 15th a compressive force in the form of a defined and monitorable contact pressure can be generated around the electrode 1 inside the through opening 12th of the housing 11 to clamp or to hold.

For loosening the electrode 1 is in the second embodiment of the electrode holding device 10 according to 3rd and. 4th a return spring 22nd provided on the bolt B2 or the hydraulic cylinder 20th works. If the hydraulic cylinder 20th is not actuated, the return spring causes 22nd a movement of the pressure piece 15th away from the outer peripheral surface of the electrode 1 (i.e. in the view of 3rd from left to right), thus clamping the electrode 1 inside the through opening 12th of the housing 11 will be annulled.

The two embodiments of the electrode holding device according to the invention explained above 10 are identical in their external dimensions. This applies in particular to the interface to the electrode support arm 2 which is copper-plated and mechanically processed, especially in the event that the base material consists of steel. The same applies accordingly to the electrode support arm 2 . While the electrode holders in the form of the electrode holding devices have threaded blind holes in the contact surfaces, there are through holes opposite them on the support arm side. The electrode holding devices are fastened in a pretensioned connection with expansion screw bolts, the pretensioning also ensuring the required contact pressure for low-loss electrical contact between the assemblies.

Due to the design features described above, the electrode holding devices 10 according to the first and second embodiment, each from the electrode support arm 2 removable and interchangeable. This also makes it possible to carry out maintenance under workshop conditions. A standardization of the electrode support arm 2 regarding the use of both electrode holders 10 , namely on the one hand according to the first embodiment of 1 or. 2 and on the other hand according to the second embodiment of FIG 3rd or. 4th , is also possible.

1. i) Standardhaltevorrichtung:
   • - Stromführend - beispielsweise besteht das Gehäuse 11 komplett aus Stahl (z.B. kupferplattiert) oder aus Aluminium, wobei zur Stromführung an dem Gehäuse 11 ein kupferplattiertes Stahlblech 25 (vgl. 1, 3) angebracht ist;
   • - Wassergekühlt;
   • - Elektrode 1 wird durch Federvorspannung gehalten (dies entspricht der Sicherheitserfordernis nach Norm), wobei zum Lösen der Elektrode 1 die Vorspannung hydraulisch durch das Stellglied 18 aufgehoben wird (vgl. 1, 2).
2. ii) Nachsetzhaltevorrichtung:
   • - Nicht stromführend;
   • - Wassergekühlt;
   • - Elektrode 1 wird durch Federvorspannung gehalten (dies entspricht der Sicherheitserfordernis nach Norm), wobei zum Lösen der Elektrode 1 die Vorspannung hydraulisch durch das Stellglied 18 aufgehoben wird (vgl. 1, 2).
3. iii) Nippelstandhaltevorrichtung (Typ 1)
   • - Nicht stromführend;
   • - Ungekühlt;
   • - Elektrode 1 wird durch Federvorspannung gehalten (dies entspricht der Sicherheitserfordernis nach Norm), wobei zum Lösen der Elektrode 1 die Vorspannung hydraulisch durch das Stellglied 18 aufgehoben wird (vgl. 1, 2);
   • - Auf einer (nicht gezeigten) Bodenplatte aufgeschweißt;
   • - Berücksichtigung einer Elektrodenzentrierung inklusive einer Annippelvorrichtung.
4. iv) Elektrodenhaltevorrichtung:
   • - Stromführend - beispielsweise besteht das Gehäuse 11 komplett aus Stahl (z.B. kupferplattiert) oder aus Aluminium, wobei zur Stromführung an dem Gehäuse 11 ein kupferplattiertes Stahlblech 25 (vgl. 1, 3) angebracht ist;
   • - Wassergekühlt;
   • - Elektrode 1 wird hydraulisch per Plungerzylinder 20 gehalten, mit dem zum Halten der Elektrode 1 ein definierter und überwachbarer Anpressdruck erzeugt wird (vgl. 3, 4);
   • - Kann mit der Variante gemäß Ziffer ii) kombiniert werden, zur Berücksichtigung einer Nachsetzvorrichtung gemäß DE 10 2013 224 552 A1 .
5. v) Nippelstandhaltevorrichtung (Typ 2)
   • - Nicht stromführend;
   • - Ungekühlt;
   • - Elektrode 1 wird hydraulisch per Plungerzylinder 20 gehalten, mit dem zum Halten der Elektrode 1 ein definierter und überwachbarer Anpressdruck erzeugt wird (vgl. 3, 4);
   • - Auf einer (nicht gezeigten) Bodenplatte aufgeschweißt;
   • - Berücksichtigung einer Elektrodenzentrierung inklusive einer Annippelvorrichtung.

In connection with the already explained possible standardization or exchangeability of the electrode holding devices 10 according to the first and second embodiment in relation to their interface to an electrode support arm 2 and for the electrode diameter, different series with the following variants are possible for the invention, the features of which are summarized as follows:

1. i) Standard holding device:
   • - Live - for example, there is the housing 11 completely made of steel ( z .B. copper-plated) or made of aluminum, whereby for current management on the housing 11 a copper-clad steel sheet 25th (see. 1 , 3rd ) is appropriate;
   • - water cooled;
   • - electrode 1 is held by spring preload (this corresponds to the safety requirement according to the standard), whereby for loosening the electrode 1 the preload hydraulically by the actuator 18th is canceled (cf. 1 , 2 ).
2. ii) Follow-up holding device:
   • - Not live;
   • - water cooled;
   • - electrode 1 is held by spring preload (this corresponds to the safety requirement according to the standard), whereby for loosening the electrode 1 the preload hydraulically by the actuator 18th is canceled (cf. 1 , 2 ).
3. iii) Nipple Stand Retention Device (Type 1)
   • - Not live;
   • - Unrefrigerated;
   • - electrode 1 is held by spring preload (this corresponds to the safety requirement according to the standard), whereby for loosening the electrode 1 the preload hydraulically by the actuator 18th is canceled (cf. 1 , 2 );
   • - Welded onto a base plate (not shown);
   • - Consideration of electrode centering including a nipple device.
4. iv) Electrode holder:
   • - Live - for example, there is the housing 11 completely made of steel ( z .B. copper-plated) or made of aluminum, whereby for current management on the housing 11 a copper-clad steel sheet 25th (see. 1 , 3rd ) is appropriate;
   • - water cooled;
   • - electrode 1 is hydraulic via plunger cylinder 20th held with the one to hold the electrode 1 a defined and monitorable contact pressure is generated (cf. 3rd , 4th );
   • - Can be combined with the variant according to point ii) to allow for an adjustment device according to DE 10 2013 224 552 A1 .
5. v) nipple holding device (type 2)
   • - Not live;
   • - Unrefrigerated;
   • - electrode 1 is hydraulic via plunger cylinder 20th held with the one to hold the electrode 1 a defined and monitorable contact pressure is generated (cf. 3rd , 4th );
   • - Welded onto a base plate (not shown);
   • - Consideration of electrode centering including a nipple device.

At this point it should be emphasized again that on the basis of the standardization mentioned above, the add-on and built-in parts for the electrode holding device according to the invention are also used 10 can be interchanged within a series.

If the electrode holder 10 is equipped with a current lead, the contact jaw is reduced to two massive but comparatively thin copper strips 25th , which on the inner peripheral surface 13th the passage opening 12th against the housing 11 are screwed. Current and heat transfer takes place there via the copper-plated sheet steel (not shown) of the housing. It is true that the copper-clad sheet steel surface becomes the electrode holder 10 therefore larger, but the copper volume of the contact pieces is reduced by approx. 20% compared to the contact jaw. Furthermore, the contact jaws do not have their own cooling circuit 25th more required.

6th Figure 3 shows a simplified perspective view of a system according to the invention 100 for repositioning an electrode 1 a metallurgical furnace (not shown). With such a system 100 the repositioning of an electrode can be implemented, for example from DE 10 2013 224 552 A1 is known.

The system 100 comprises at least two electrode holding devices 10 that are in the vertical direction z are arranged one above the other. Here is the lower electrode holder 10 formed according to the aforementioned variant iv), wherein the upper electrode holding device 10 is designed according to the aforementioned variant ii). With such a configuration of the lower and upper electrode holding devices 10 , 10 .2 it is achieved that at least one electrode holding device is always closed (in order to prevent the electrode strand from falling), while it is possible, for example, to move the upper electrode holding device up and down. This is how the electrode can be repositioned or moved 1 or of the electrode line vertically in both directions.

The lower electrode holding device corresponds to variant iv) 10 equipped with a current lead, whereas the upper electrode holder 10 , in accordance with variant ii), is not live.

Between the lower electrode holder 10 and the upper electrode holder 10 is an additional hoist 110 provided that consists of three hydraulic plunger cylinders 112 (or P ₁ , P ₂ , P ₃ , cf. 6th ) per electrode holder. Specifically, these are three plunger cylinders 112 each on the lower electrode holder 10 attached or protected received therein, the (not shown) piston rods of this plunger cylinder 112 each with the upper electrode holder 10 are connected. In this context, it is pointed out separately that the piston rods are opposite to the non-current-carrying upper electrode holding device 10 are electrically isolated to allow current to flow through the plunger cylinders 112 to prevent.

The simplified top view according to 7th Figure 3 illustrates an arrangement of the three plunger cylinders 112 on an electrode holder 10 . Here, a first plunger cylinder P ₁ and a second plunger cylinder P _{2 are} on the side of the through opening 12th of the housing 11 arranged on which the pressure piece 15th is provided. In contrast, the third plunger cylinder P _{3 is located} on the opposite side of the through opening opposite the pressure piece 15th . Thus, in a horizontal plane, these three plunger cylinders P ₁ , P ₂ , P _{3 form} a triangle D. (in 7th symbolized with dashed lines) spanned, with the center of gravity S of the mass to be raised or to fall, ie an electrode 1 - viewed from above - always within this triangle D. is located. This minimizes bending stresses in the piston rods 113 of the plunger cylinders 112 reached.

With regard to the aforementioned arrangement of the three plunger cylinders 112 (or P ₁ , P ₂ , P ₃ ) it is emphasized that such an arrangement is only possible through the design of the electrode holding device according to the invention 10 in solid box construction, ie with a housing 11 in the form of an elongated box is possible. Due to the larger cross-sections, this also leads to a reduction in mechanical stresses and makes the bending-free arrangement of a readjusting device possible in the first place.

The in 6th shown system 100 are a total of three pairs of electrode holders 10 provided, each consisting of a lower electrode holder 10 according to variant iv) and an upper electrode holding device 10 are formed according to variant ii).

• Das Nachsetzen bei eingeschaltetem Ofen, d.h. unter „power on“, erfordert einen definierten und überwachbaren Anpressdruck für die Elektrode 1, um sie in der Durchgangsöffnung 12 des Gehäuses 11 zu klemmen bzw. zu halten. Auf Grund der Toleranzen beim Elektrodendurchmesser schwanken auch der Federweg und somit auch die Federkraft des Federpaketes 17. Aus diesen Gründen wird der Elektrodenstrang in der stromführenden unteren Elektrodenhaltevorrichtung 10 direkt hydraulisch aufgebracht wird. Das bedeutet, dass aus Sicherheitsgründen nur bei eingeschwenktem Ofendeckel nachgesetzt werden darf.

The following describes the operation of a metallurgical furnace using an electrode holder 10 or the system equipped with it 100 according to the present invention as follows:

• Repositioning with the furnace switched on, ie under "power on", requires a defined and monitorable contact pressure for the electrode 1 to place them in the through hole 12th of the housing 11 to clamp or to hold. Due to the tolerances in the electrode diameter, the spring deflection and thus the spring force of the spring assembly also fluctuate 17th . For these reasons, the electrode string is in the current-carrying lower electrode holding device 10 is applied directly hydraulically. This means that, for safety reasons, you may only re-insert when the furnace lid is swiveled in.

The possibility of introducing electrical power into the furnace while the electrodes are being repositioned requires the contact pressure in the current-carrying lower electrode holding device 10 lower so that the electrode assembly can slip through (safety against slipping through <1). It should be noted that this increases the electrical transition resistance, which can lead to heating in the contact surface. If necessary, the furnace can only be operated with reduced electrical power during the reloading under "power on". This controlled sliding of the electrode strand or the electrode 1 through the live lower electrode holder 10 is only up to the interface of two electrodes 1 possible, since it cannot be ruled out that there will be protruding or receding edges due to the diameter tolerances of the electrodes can occur (broken edges, reduction in the contact area). As a result, the contact may have to be completely canceled at this point, and in a stroke movement, under “power off”, it must be readjusted until the pressure piece passes the interface completely. It should be noted that the repositioning stroke must be limited for space reasons. Repositioning over the entire box area in one lifting movement (2x box height plus 1x contact jaw height = approx. 1000 mm) is therefore not possible. For mechanical reasons it follows from this that the contact pressure in the area of the box must be reduced in order not to destroy it. Apart from these restrictions, the repositioning stroke can take place continuously, which means a maximum stroke length of the repositioning stroke or plunger cylinder 112 corresponds to.

During the "power on" times, in which there is no follow-up, the contact pressure from the hydraulic cylinder corresponds 20th the spring force at the working point.

The electrode holders 10 , 10 .2 now form an independent unit, which is why the construction of the electrode support arms 2 simplified in this regard (e.g. welding sequence). A conversion of already existing electrode support arms 2 is possible.

Electrode maintenance and nipple stands can also be carried out using at least one electrode holding device according to the invention 10 be constructed. This is equivalent to variants iii) and v) already mentioned above, ie without copper plating and without contact flange (not carrying current, not water-cooled) taking into account electrode centering including a nipple device.

8th Figure 3 shows a simplified view of such an electrode maintenance stand 200 ("Nipple device"), which is a screw device 210 , an electrode guide / centering 220 and at least one electrode holder. As shown in 8th the electrode holder is an upper electrode holder 10 according to 6th which, as explained, is designed to be non-current-carrying. By means of such an electrode maintenance stand 200 it is possible to have two separate electrode strands 1 to be connected to one another at their end faces.

List of reference symbols

1

electrode

2

Electrode support arm

10

Electrode holder

11

casing

12th

Through opening (of the housing 11 )

13th

Inner peripheral surface (of the through hole 12th )

14th

Electrode arm head

15th

Pressure piece

16

Spring element

17th

Spring package

18th

Actuator (e.g. hydraulic cylinder)

19th

central through hole (in the actuator 20th )

20th

Hydraulic cylinder (e.g. plunger cylinder)

22nd

Return spring

24

element

25th

Copper strips or metal strips coated with copper

100

System for repositioning an electrode in a metallurgical furnace

110

Back-up hoist

112

Plunger cylinder ( z .B. P ₁ , P ₂ , P ₃ )

200

Electrode maintenance status ("nipple device")

210

Screwing device

220

Electrode guidance / centering

B1

Bolt (for spring package 17th )

B2

Bolt (in connection with hydraulic cylinder 20th )

D.

triangle

z

vertical direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102013224552 A1 [0030, 0051, 0054]

Claims (18)

Electrode holding device (10), comprising a housing (11) and a pressure piece (15) movably guided therein, the pressure piece (15) being movable against an electrode (1) with a predetermined clamping force, characterized in that the housing (11) is in Is designed in the form of an elongated box and has a vertically running through opening (12) through which the electrode (1) extends, and that the pressure piece (15) is arranged adjacent to the through opening (12) of the housing (11) and only from one Side against the electrode (1) using a spring element (16) or a hydraulic cylinder (20) to exert a compressive force on the electrode (1) and thereby the electrode (1) within the through opening (12) of the housing ( 11) to jam. Electrode holding device (10) according to Claim 1 , characterized in that the housing (11) is integrated in an electrode support arm head (14), preferably that the housing (11) and the electrode support arm head (14) are formed integrally with one another. Electrode holding device (10) according to Claim 1 , characterized in that the housing (11) can be detachably attached to an electrode support arm head (14). Electrode holding device (10) according to one of the Claims 1 to 3rd , characterized in that a spring element (16), preferably in the form of a spring assembly (17), is provided to exert a compressive force on the pressure piece (15) in the direction of the electrode (1) and is arranged within the housing (11) and in operative connection _{with a bolt (B 1} ) connected to the pressure piece (15). Electrode holding device (10) according to Claim 4 , characterized in that an actuator (18), preferably in the form of a hydraulic cylinder, is fastened within the housing (11), with which _{a force can be applied to the bolt (B 1} ) which is opposite to the force of the spring element (16) or spring assembly (17) works. Electrode holding device (10) according to Claim 5 , characterized in that the actuator (18) is arranged between the pressure piece (15) and the spring element (16) or spring assembly (17), the actuator (18) having a central through hole (19) through which the Bolt (B ₁ ) extends. Electrode holding device (10) according to one of the Claims 1 to 3rd , characterized in that a hydraulic cylinder (20), preferably in the form of a plunger cylinder, is provided to exert a pressure force on the pressure piece (15) in the direction of the electrode (1), which is arranged within the housing (11) and in operative connection with a the pressure piece (15) connected to the bolt (B ₂ ). Electrode holding device (10) according to Claim 7 , characterized in that at least one return spring (22) is provided inside the housing (11) which _{acts on the bolt (B 2} ) or the hydraulic cylinder (20) and thereby a return of the pressure piece (15) away from the electrode (1 ) causes when the hydraulic cylinder (20) is not actuated. Electrode holding device (10) according to one of the preceding claims, characterized in that a current lead is provided for the electrode (1). Electrode holding device (10) according to Claim 9 , characterized in that the current conduction comprises at least one element (24) which consists of copper or aluminum or is at least coated with copper, preferably that the element (24) for current conduction on an inner circumferential surface (13) of the through opening (12) of the housing (11) is attached opposite to the pressure piece (15). Electrode holding device (10) according to Claim 10 , characterized in that the element (24) of the current lead is formed from a copper strip (25) or from a metal strip coated with copper. Electrode holding device (10) according to one of the Claims 9 to 11 , characterized in that the housing (11) is equipped with water cooling. Electrode holding device (10) according to one of the Claims 9 to 12th , characterized in that the housing (11) is equipped with copper-clad sheet steel to conduct current for the electrode (1). Electrode holding device (10) according to one of the preceding claims, characterized in that the housing (11) consists of aluminum or has parts made of aluminum. System (100) for repositioning an electrode (1) of a metallurgical furnace, comprising at least two electrode holding devices (10) according to one of the Claims 1 to 14th , which are arranged one above the other in the vertical direction (z), and at least one Nachsetzhubwerk (110), which consists of three hydraulic plunger cylinders (112), the are each attached to the lower electrode holding device (10.1), the piston rods (113) of the plunger cylinder (112) being connected to the upper electrode holding device (10.2). System (100) according to Claim 15 , characterized in that two plunger cylinders (P1; P2) of the adjustment lifting mechanism (110) are attached to the side of the through opening (12) of the housing (11) on which the pressure piece (15) is provided, the third plunger cylinder (P3) is attached on the opposite side of the through opening (12) opposite to the pressure piece (15), so that a triangle (D) is _{spanned in a horizontal plane with the three plunger cylinders (P 1} , P ₂ , P _{3) of the post-lift mechanism (110)} , within which the center of gravity (S) of the electrode (1) is located. System (100) according to Claim 15 or 16 , characterized in that the lower of the two electrode holding devices (10.1) with a current lead according to one of the Claims 9 to 14th and the upper of the two electrode holding devices (10.2) is not current-carrying, the piston rods (113) of the plunger cylinder (112) being designed to be electrically insulated from the upper electrode holding device (10.2). Electrode maintenance stand (200), in particular for connecting two electrode strands (1), comprising a screwing device (210), an electrode guide / centering device (220) and at least one electrode holding device (10) according to one of the Claims 1 to 14th .

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