EP2783178B1 - Arc furnace with a furnace cover support arm system - Google Patents

Description

The present invention relates to an electric arc furnace, with at least one furnace vessel, a furnace lid and with a furnace lid associated Tragarmsystem with which the furnace lid on the furnace vessel via a connected to the Tragarmsystem pivoting and / or lifting portal is formed and lowered and at least one Electrode support over which an electrode is raised and lowered formed by at least one passage opening in the furnace lid.

From the state of the art arc furnaces, so-called. EAF ovens, with Tragarmsystemen for the furnace lid known in which water-cooled boom are provided which hold the furnace lid in a 3-point suspension - in a V-arrangement. Furthermore, self-supporting Einarmige furnace cover systems are known, which is associated with its own Deckelhub- and slewing gear. Such generic arc furnaces are for example from the DE 1 940 740 and the DE 3 522 559 known. Furthermore, the DE 1 216 900 a device for coupling the lift-off furnace lid to the electrode lifting device of an electric arc furnace.

From the publication DE 44 38 710 A1 is a Deckelhubwerk for a means of a lifting device placed on a metallurgical vessel and liftable by this lid known. To be able to accomplish the lifting and lowering of the lid with a low design effort, the lid is hinged to the support column via at least one operable by means of the lifting device four-bar linkage, the web of the support column and the coupling of a part of the cover having a lid construction is formed ,

This Tragarmsysteme have proven useful, but are associated with the disadvantage that, for example, in the 3-point suspension of the furnace lid three annular space used, double-acting lift cylinders in the immediate vicinity of the current-carrying components, such as the electrode support arms are arranged. This often leads to damage caused by current flow due to induction and / or arcing on the cylinders themselves. Furthermore, with such a configuration, additional cooling of the lifting systems of the support arms is essential. This results in the disadvantage of a costly cooling water supply with very long cooling water pipes, from a Transformatorenhauswand to the furnace cover. This results in an increased risk potential in the operation of such a furnace equipped, since, for example, in a demolition of the coolant line to the furnace cover, cooling water passes in large quantities directly into the pan provided for tapping. The installation and removal of a lid change during operation is due to the complicated management of the coolant lines, associated with a significant additional logistical effort.

Also, the maintenance and / or replacement of components due to the design-related poor accessibility are time consuming and therefore costly. Another disadvantage arises from the transport and assembly of the lid support arms, which are cumbersome and difficult to perform. The coordination of the lid suspension points between the furnace cover and the support arms is very cumbersome and associated with great welding effort.

In self-supporting furnace covers with a one-armed Deckelhup- and swivel system, it comes, due to the one-armed structure, to a significant deformation of the furnace lid when lifting. This circumstance considerably shortens the service life of such a furnace cover, which in turn is associated with a considerable additional operating cost. The above-mentioned disadvantages of the coolant line guide apply equally to these lid systems. Furthermore, such systems require a separate cover turning with associated drive.

It is therefore an object of the present invention to provide a generic arc furnace, which is characterized by a simpler, more robust design, easy to assemble and maintain, is characterized by a longer life and thus the manufacturing and investment costs can be kept low.

These objects are achieved by the features specified in claim 1, in particular by a piston side used, single-acting hydraulic cylinder, which is hinged to the base of the rotary and / or lifting portal at a first receiving point, and at a second receiving point .der in alignment aligned to the first pick-up point and arranged on a recording facial expressions and is rotatably mounted, wherein the recording facial features is designed as a lever and rotatably mounted on the rotary and / or lifting portal on a recording associated with this, and the recording facial expressions with the Tragarmsystem the furnace cover is connected, and the furnace lid can be raised / lowered and folded over the receptacle mimics that can be connected to the support arm system.

By this arrangement, it is possible to reduce the number of cylinders of the Deckelhubwerkhydraulik on a hydraulic cylinder. Furthermore, this is a direct and simplified installation and maintenance friendly Access to the lid lifting hydraulic cylinder, a so-called plunger, on the lifting and / or rotating portal possible. Also, the service life of the hydraulic cylinder is considerably extended by this arrangement, as this allows a much greater distance from the live parts.

According to a further particularly advantageous embodiment of the EAF furnace according to the invention, the self-supporting Tragarmsystem the furnace lid is formed from spokes pairs crossing at right angles, wherein the pair of spokes, which is formed parallel to the transverse axis of the furnace vessel (bend plane) extended over the edge of the lid. This leads to a weight reduction of the entire construction in the area of the furnace cover. The conventional support arms for a cover can be omitted in favor of a self-supporting furnace cover. This also leads to a considerable simplification in the cooling of the furnace lid and to simplify the Kühlmittelzu and - return lines. Furthermore, by such an arrangement, a shortening of the coolant connections through the rotary and / or lifting tower and below a tilting stage associated with the furnace is possible. Due to the simplified coolant supply, the cover replacement time can be shortened considerably.

In a further particularly advantageous embodiment of the EAF according to the invention, the radial spokes have free ends, wherein the free ends are associated with pin joints. By this measure, the mechanical and thermal forces acting on the rotary and / or lifting portal can be reduced to a minimum. By the self-supporting, hinged at two points on the rotating and / or lifting portal or supported, electrically decoupled, furnace cover the service life of the entire system is considerably extended.

In a further embodiment, it is provided to non-positively connect the pin joints with bearing cavities arranged on the receiving mimic, wherein the furnace lid can be lifted and / or folded over the supporting arm system.

It is particularly advantageous that the recording facial expressions can be lowered by the hydraulic cylinder to the extent that the pin joints are posted at the free ends of the Tragarmsystems from the storage cavities of the recording facial expressions and the furnace cover is mechanically and electrically decoupled from the rotary and / or lifting portal.

According to a further advantageous embodiment of the present invention, the geometry between the hydraulic cylinder, and the receiving points for the Tragarmsystem is selected on the recording facial that horizontal displacements are generated when lifting the furnace cover, which negligible in the region of the openings of the electrodes through the furnace lid are formed in the interface plane of the opening of the furnace vessel so that adhesions of the furnace lid with the edge of the furnace vessel over shear stresses generated by the cover movement are solvable. Negligibly small in this context means that the relative movement between the guided through the passage opening electrode and the furnace lid is so small that it leads to no contact between the electrode and the furnace lid, which would damage one or the other component.

In a particularly preferred embodiment of the present invention, the recording facial expression is formed as a lever and rotatably mounted on the rotary and / or lifting portal on one of these associated recording and connected to the second pick-up point of the recording mimic with the hydraulic cylinder.

Furthermore, it is provided that the coolant lines of the coolant supply system guided in installation position from below through the rotary portal, exit on the side facing away from the hydraulic cylinder from the rotary portal, extending over the top parallel to the recording facial and connected to a furnace cover associated with the flange connection. Thus, the coolant lines can be shortened and the installation can be carried out more efficiently, since the rotary and / or lifting portal is now an integral part of the coolant supply system.

In the rotary and / or lifting portal according to the invention, the previously provided lid support arms can be omitted. This leads to a reduction in construction height of at least 2 meters and the associated need to cool these components. Savings result not only in the area of significant weight reduction of the lid construction and the elimination of the cost of producing elaborate welded structures, but also in the assembly of these brackets, since the overhead for aligning and welding the brackets omitted on the rotary portal. With regard to the guidance and arrangement of the electrode guide columns, nothing changes in the structure of the rotary and / or lifting portal.

The cooling water supply to the furnace lid is no longer as usual over long, coming from the transformer house wall hose lines, but lead directly from below through the rotary portal. Although hose lines are also provided here, but they are relatively short and less prone to tearing and thus less dangerous for the oven operation, as in a damage to the hoses no cooling water with the liquid Steel can come into contact. From the rotary portal, the cooling water is led via short hoses flexible and electrically non-conductive to the furnace lid. On and / or on the furnace cover flange connections are provided, which are easy and comfortable to reach.

The furnace cover segments are still supported by a cooling frame with a pipe frame (cooling water distributor and collector). Radial spokes are replaced by pairs of spokes crossing at right angles. The pair of spokes, which runs parallel to the furnace transverse axis (bend plane), is extended beyond the edge of the cover. At the free ends of these spokes is a pin joint for receiving by the receiving facial expressions (designed as Deckelhubwerkarme). Parallel thereto, brackets are provided on the lower cover ring, each with a pressure plate as counterparts to those of the Deckelhubwerkes (as forces). The furnace cover can be reached via a fixed staircase on the tilting platform. A stage level on the furnace lid provides direct access to the electrode fixtures, as well as direct and easy access to the flange connections and shut-off fittings of the furnace cover cooling water supply.

To change the lid heart or the entire lid of this is separated after the last tap of the cooling water system. Now, the rotary portal can be swung out together with the Elektrodentragarmsystem without operating the Aufnahmemimik (then trained as Deckelhubwerk). The furnace lid remains on the furnace vessel and is now free for a hall crane and easily accessible. Due to the simplified rise on the furnace cover and the direct accessibility to the cooling water system significantly shorter downtimes and thus a higher availability of such an EAF furnace can be achieved.

In order to allow access to the flange connections of the coolant guide system and the cover passages, as well as to the electrodes holding electrode clamping devices, is assigned to the furnace cover a stage level, which is accessible via a staircase. This creates the most level work surface that can be safely and comfortably committed.

The flange of the coolant guide system on the furnace lid are formed in a further advantageous embodiment of the present invention as quick couplings.

Fig. 1

eine Draufsicht auf einen erfindungsgemäßen EAF Ofen mit geschlossenem und geöffnetem Ofendeckel;

Fig.2

eine Seitenansicht auf den erfindungsgemäßen EAF Ofen mit Hub- und/oder Drehportal und geschlossenem Ofendeckel mit eingefahrenem Hydraulikzylinder;

Fig. 3

eine Seitenansicht auf den erfindungsgemäßen EAF Ofen mit angefahrenen Hydraulikzylinder kurz vor dem Anheben des Ofendeckels;

Fig. 4

eine Seitenansicht des erfindungsgemäßen EAF Ofens mit durch den Hydraulikzylinder angekipptem Ofendeckel;

Fig. 5

eine Seitenansicht des erfindungsgemäßen EAF Ofens mit vollständig durch den Hydraulikzylinder angehobenen Ofendeckel.

The invention will be explained in more detail below with reference to an exemplary embodiment with reference to the accompanying drawings. Show it:

Fig. 1

a plan view of an inventive EAF oven with closed and open furnace lid;

Fig.2

a side view of the invention EAF oven with lifting and / or rotating portal and closed furnace lid with retracted hydraulic cylinder;

Fig. 3

a side view of the invention EAF furnace with started hydraulic cylinder just before lifting the furnace lid;

Fig. 4

a side view of the invention EAF oven with tipped by the hydraulic cylinder furnace lid;

Fig. 5

a side view of the EAF furnace according to the invention with fully raised by the hydraulic cylinder furnace cover.

As the Fig. 1 to 5 show, the electric arc furnace 10 according to the invention essentially consists of a furnace vessel 11 which is tiltably mounted on a tilting platform 12. The furnace vessel 11 can be covered with a furnace lid 13. Lowered or raised and / or pivoted the furnace lid 13 with a rotating and / or lifting portal 14, as this particular Fig. 1 can be seen, in which the furnace lid 13 is also shown as a pivoted furnace lid 13a.

The furnace cover 13 is a self-supporting structure and forms a support arm system 26. For this purpose, radial spokes 15, 16 and 17, 18 interconnected at right angles crossing to the supporting skeleton. The pair of spokes 17, 18, which runs parallel to the furnace transverse axis (bend plane), is formed extended beyond the lid edge 19 of the furnace lid 13. The spokes 17, 18 have free ends 20, 21, which pin joints 33, 34 are assigned.

A receiving mimic 22 designed as a lever arm is assigned to the rotary and / or lifting portal 14. The recording facial expressions 22 is articulated via a receptacle 27 on the rotary and / or lifting portal 14. The recording facial expression 22 is raised by a hydraulic cylinder 28, which is articulated to the base of the rotary and / or lifting portal 14 at a first receiving point 29. With a second pick-up point 30, the hydraulic cylinder is operatively connected to the pick-up mimic 22 in alignment with the first pick-up point 29.

The recording facial expressions 22 are associated with bearing cavities 31, 32. For lifting the furnace cover 13, the receiving mimic 22 is now raised via the hydraulic cylinder 28, so that in this way the bearing recesses 31, 32 in the pin joints 33, 34 of the free ends 20, 21 of the radial spokes 17, 18 of the furnace lid 13 can engage frictionally; as this particular in Fig. 3 is shown. In order to support the moment of force of the furnace cover 13, 23 brackets 24 are provided on the lower cover ring; each having a pressure plate 25 and this as a force-pair counterpart with a receiving mimic 22 associated support region 45 lie flat.

Like in the Fig. 1 and Fig. 2 is further shown, the furnace cover 13 on its upper side 41 openings 35, 36, can be guided by the electrodes 37, 38 in the furnace vessel 11. The electrodes 37, 38 are clamped to an electrode support arm 39. It is intended to decouple the electrodes 37, 38 both mechanically and electrically from the rotary and / or lifting portal 14. The furnace cover 13 is still associated with a flue gas vent 40 through which the gassing gases produced during the melting process are derived.

The furnace cover 13 is accessible via a permanently installed on the tilting platform 12 stairs 42. A provided on the furnace cover 13 stage level 43 allows direct and easy access to the electrodes 37, 38 and their fixtures and flange connections and shut-off valves (both not shown) of a coolant guide system only partially shown 44, via which the electric arc furnace 10 are subjected to a coolant can.

The lever arm of the receiving mimic 22 is designed so that when lifting the furnace cover 13 horizontal displacements are generated, which in the region of the passage openings 35, 36 for the electrodes 37, 38 in the furnace lid 13 negligible, in the interface plane of the furnace vessel opening 46 of the furnace vessel 11 but are formed so that adhesions of the furnace lid 13 are solved with the edge 47 of the furnace vessel 11 generated by the cover movement shear stresses.

It is envisaged to form the coolant guide system 44 from a combination of rigid tubing and flexible tube sections. In order to keep the length of the individual sections as short as possible, the coolant supply system 44 is guided directly through the rotary and / or lifting portal 14. In this case, a line 48 emerges from a side facing away from the hydraulic cylinder 28 on the rotating and / or lifting portal 14 again and is passed over the Aufnahmemimik 22 to the furnace lid 13, where it is connected for example via a flange. <B> LIST OF REFERENCES </ b> 10 Arc furnace 39 An electrode 11 furnace vessel 40 Flue gas exhaust 12 tilting platform 41 Top of oven lid 13, 13a furnace cover 42 stairway 14 Turning and / or lifting portal 43 platform level 15 radial spoke 44 Coolant circulation system 16 axial spoke 45 support area 17 radial spoke 46 opening 18 radial spoke 47 edge 19 cover edge 48 management 20 free end 49 opposite side 21 free end 22 recording facial expressions 23 lower cover ring 24 console 25 printing plate 26 Support arm 27 admission 28 hydraulic cylinders 29 first pickup point 30 second pickup point 31 bearing recess 32 bearing recess 33 pin joint 34 pin joint 35 Passage opening furnace cover 36 Passage opening furnace cover 37 electrode 38 electrode

Claims (7)

1. Arc furnace, with at least one furnace vessel, a furnace cover, a support arm system, which is associated with the furnace cover and by which the furnace cover is configured to be raisable from and lowerable onto the furnace vessel by way of a rotary and/or lifting portal connected with the support arm system, and at least one electrode carrier arm by way of which an electrode is configured to be raisable and lowerable through at least one passage opening in the furnace cover,
   characterised in that
   a single-acting hydraulic cylinder (28), which is deployed at the piston side and which is pivoted at the base of the rotary and/or lifting portal (14) at a first mounting point (29) and is rotatably mounted at a second mounting point (30), is provided
   wherein the hydraulic cylinder (28) is operatively connected by way of the second mounting point (30) with a simulation mount (22) in alignment with the first mounting point (29), and
   wherein the simulation mount (22) is constructed as a lever and rotatably mounted at the rotary and/or lifting portal (14) at a mount (27) associated therewith, the simulation mount (22) being connectible with the support arm system (26) of the furnace cover (13) and the furnace cover (13) being raisable/lowerable and pivotable by way of the simulation mount (22) connectible with the support arm system (26).
2. Arc furnace according to claim 1, characterised in that the support arm system (26) of the furnace cover (13) is of self-supporting construction and is constructed from spoke pairs (15, 16, 17, 18) intersecting at right angles, the spoke pair (17, 18) being constructed to be prolonged parallelly to the transverse axis of the furnace vessel beyond the edge of the cover (13), and the radial spokes (17, 18) have free ends (20, 21) with which are associated pin joints (33, 34) which can be operatively connected by non-positive coupling with bearing troughs (31, 32) arranged at the simulation mount (22).
3. Arc furnace according to claim 2, characterised in that the simulation mount (22) can be lowered by way of the hydraulic cylinder (28) to such an extent that the pin joints (33, 34) at the free ends (20, 21) of the support system (26) are unhung from the bearing troughs (31, 32) of the simulation mount (22) and the furnace cover (13) is decoupled both mechanically and electrically from the rotary and/or lifting portal (14).
4. Arc furnace according to claim 3, characterised in that the geometry between the hydraulic cylinder (28), the bearing troughs (31, 32) of the simulation mount (22) and the support arm system (26) is formed in such a way that when the furnace cover (13) is raised by the hydraulic cylinder (28) horizontal displacements are produced which are of negligible magnitude in the region of the passage opening (35) of the electrodes (37, 38) through the furnace cover (13), but are such in the interface plane of the opening (47) of the furnace vessel (11) that adhesion of the furnace cover (13) to the edge (48) of the oven vessel (11) is released by the shear stresses generated by the cover movement.
5. Arc furnace according to claim 1, characterised in that associated with the rotary and/or lifting portal (14) is a coolant guide system (44) which in the installed position is led from below, to pass through the rotary and/or lifting portal (14) and at least one coolant duct (48) exits from the rotary and/or lifting portal (14) from a side (49) remote from the hydraulic cylinder (28) and is led over the simulation mount (22) to the furnace cover (13) and connected therewith by way of a flange connection.
6. Arc furnace according to claim 5, characterised in that the flange connection is constructed at the furnace cover (13) as a quick-action coupling.
7. Arc furnace according to claim 6, characterised in that associated with the furnace cover (13) is a platform plane (43) which enables direct and simple access to the flange connection of the coolant guide system (44) and to electrode clamping devices associated with the cover passage openings (35, 36).

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