DE102011119797A1 - Electric arc furnace with a furnace lid support arm system - Google Patents

Abstract

Electric arc furnace (10) with at least one furnace vessel (11), a furnace lid (13) and with a support arm system (26) assigned to the furnace cover (13), with which the furnace cover (13) can be pushed onto the furnace vessel (11) via a support arm system (Fig. 26) connected to at least one electrode support arm (39) above the one electrode (37, 38) through at least one passage opening (35, 36) in the furnace cover (26) connected rotary and / or lifting portal (14) rotatable and / or raised and lowered 13) is raised and lowered formed; with a piston side used, single-acting hydraulic cylinder (28) which is hinged to the base of the rotary and / or lifting portal (14) at a first receiving point (29) and with a the rotary and / or lifting portal (14) associated with recording facial expressions (22) at a second receiving point (30) which is aligned in alignment with the first receiving point (29) is rotatably mounted.

Description

The present invention relates to an electric arc furnace, comprising at least one furnace vessel, at least one furnace lid and at least one support arm system associated with the furnace lid, with which the furnace lid can be raised and lowered onto the furnace vessel via a rotating and / or lifting portal connected to the support arm system.

From the prior art arc furnace, so-called. EAF furnaces, known with Tragarmsystemen for the furnace lid, are provided in the water-cooled boom, 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 furnace 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.

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, in 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 on 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 vote of Deckelaufhängepunkte between the furnace lid and the support arms is very cumbersome and associated with great welding effort.

In self-supporting furnace covers with a one-armed Deckelhub- and pivoting 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 with a rotary and / or lifting portal associated recording facial expressions at a second pick-up point, which is aligned in alignment with the first pick-up point, is rotatably mounted. 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 easy to access and easy to access Deckelhubhydraulikzylinder, 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 cover is formed from perpendicular crossing spokes pairs, the pair of spokes, which is 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 costs of the furnace lid and to simplify the coolant supply 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 platform associated with the furnace 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 lid 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 receiving 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 furnace operation, since in case of damage to the hoses no cooling water can come into contact with the liquid steel. 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 pipe frame with cooling water (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 allows direct access to the electrode clamping devices, as well as direct and easy access to the flange connections and the shut-off valves 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 of the coolant supply system and the cover passage openings, as well as the electrodes holding electrode clamping devices, the furnace cover is associated with 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.

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

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

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

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

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

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

As the 1 to 5 show, there is the electric arc furnace according to the invention 10 essentially from a furnace vessel 11 on a tilting stage 12 tiltable is stored. The furnace vessel 11 is with a furnace lid 13 coverable. Lowered or raised and / or pivoted the furnace lid 13 with a rotating and / or lifting portal 14 like this particular 1 it can be seen in the furnace lid 13 also as a pivoted furnace lid 13a is shown.

The furnace lid 13 is a self-supporting construction and forms a support arm system 26 out. This will be radial spokes 15 . 16 and 17 . 18 crossing each other at right angles to the supporting skeleton. The spokes pair 17 . 18 , which runs parallel to the furnace transverse axis (bend plane), is above the edge of the lid 19 of the furnace lid 13 also formed extended. The spokes 17 . 18 have free ends 20 . 21 on which pin joints 33 . 34 assigned.

A trained as a lever arm recording facial expressions 22 is the turning and / or lifting portal 14 assigned. The recording facial expressions 22 is about a recording 27 at the turning and / or lifting portal 14 hinged. Raised is the recording facial expressions 22 via a hydraulic cylinder 28 located at the base of the rotary and / or lifting portal 14 at a first pick-up point 29 is articulated. With a second pick-up point 30 is the hydraulic cylinder with the recording facial expressions 22 in alignment with the first pick-up point 29 operatively connected.

The recording facial expressions 22 are storage troughs 31 . 32 assigned. To lift the furnace lid 13 is now the recording facial expressions 22 over the hydraulic cylinder 28 raised so that thereby the storage pits 31 . 32 in the pin joints 33 . 34 the free ends 20 . 21 the radial spokes 17 . 18 of the furnace lid 13 can intervene force-locking; as this particular in 3 is shown. To the moment of force of the furnace cover 13 to be able to support, are on the lower cover ring 23 consoles 24 provided, each a pressure plate 25 have and as this forces counterpart with one of the recording facial expressions 22 associated support area 45 lie flat.

Like in the 1 and 2 is further shown, the furnace lid 13 at its top 41 openings 35 . 36 on, through the electrodes 37 . 38 in the oven vessel 11 can be performed. The electrodes 37 . 38 are on an electrode support arm 39 clamping kept. It is envisaged the electrodes 37 . 38 both mechanically and electrically from the rotary and / or lifting portal 14 to decouple. The furnace lid 13 is still a flue gas outlet 40 assigned, over which the gassing gases resulting from the melting process are derived.

The furnace lid 13 is about one on the tilting stage 12 permanently installed stairs 42 accessible. One on the furnace lid 13 planned stage level 43 allows direct and easy access to the electrodes 37 . 38 and their clamping devices as well as flange connections and shut-off valves (both not shown) of a coolant guide system only partially shown 44 about which the electric arc furnace 10 can be acted upon with a coolant.

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

It is envisaged the coolant supply system 44 form a combination of rigid pipes and flexible hose sections. In order to keep the length of the individual sections as short as possible, the coolant supply system 44 directly through the rotating and / or lifting portal 14 guided. Here comes a line 48 from a hydraulic cylinder 28 opposite side on the rotating and / or lifting portal 14 back out and about the recording facial expressions 22 to the furnace lid 13 where it is connected via a flange connection, for example.

LIST OF REFERENCE NUMBERS

10

Arc furnace

11

furnace vessel

12

tilting platform

13, 13a

furnace cover

14

Turning and / or lifting portal

15

radial spoke

16

axial spoke

17

radial spoke

18

radial spoke

19

cover edge

20

free end

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

39

An electrode

40

Flue gas exhaust

41

Top of oven lid

42

stairway

43

platform level

44

Coolant circulation system

45

support area

46

opening

47

edge

48

management

49

opposite side

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 1940740 [0002]
• DE 3522559 [0002]
• DE 1216900 [0002]

Claims (10)

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 rotary and / or lifting portal is rotating and / or raised and lowered and formed with at least one Elektrodentragarm above which an electrode can be raised and lowered by at least one passage opening in the furnace lid, characterized by a piston-side, single-acting hydraulic cylinder ( 28 ) located at the base of the rotary and / or lifting portal ( 14 ) at a first pick-up point ( 29 ) is hinged, and with a rotary and / or lifting portal ( 14 ) associated with recording facial expressions ( 22 ) at a second pick-up point ( 30 ), which is in alignment with the first pick-up point ( 29 ) is aligned, is rotatably mounted. Arc furnace according to claim 1, characterized in that the support arm system ( 26 ) of the furnace lid ( 13 ) self-supporting and formed of perpendicularly crossing pairs of spokes ( 15 . 16 . 17 . 18 ) and the spoke pair ( 17 . 18 ) parallel to the transverse axis of the furnace vessel (bend plane) over the edge of the lid ( 13 ) is formed extended. Arc furnace according to claim 2, characterized in that the radial spokes ( 17 . 18 ) free ends ( 20 . 21 ) and the free ends ( 20 . 21 ) Pin joints ( 33 . 34 ) assigned. Arc furnace according to claim 3, characterized in that the pin joints ( 33 . 34 ) with on the recording facial expressions ( 22 ) arranged storage troughs ( 31 . 32 ) are frictionally operatively connected, and the furnace lid ( 13 ) via the support arm system ( 26 ) is liftable and / or hinged. Arc furnace according to claim 4, characterized in that the recording facial expressions ( 22 ) via the hydraulic cylinder ( 28 ) is lowered so far that the pin joints ( 33 . 34 ) at the free ends ( 20 . 21 ) of the support arm system ( 26 ) from the storage troughs ( 31 . 32 ) of the recording facial expressions ( 22 ) and the furnace lid ( 13 ) both mechanically and electrically from the rotary and / or lifting portal ( 14 ) is decoupled. Arc furnace according to one or more of the preceding claims, characterized in that the geometry between the hydraulic cylinder ( 28 ) and the storage troughs ( 31 . 32 ) of the recording facial expressions ( 22 ) and the support arm system ( 26 ) is designed such that when lifting the furnace lid ( 13 ) by the hydraulic cylinder ( 28 ) horizontal displacements are generated, which in the region of the passage opening ( 35 ) of the electrodes ( 37 . 38 ) through the furnace lid ( 13 ) negligible, but in the interface plane of the opening ( 47 ) of the furnace vessel ( 11 ) are formed so that adhesions of the furnace cover ( 13 ) with the edge ( 48 ) of the furnace vessel ( 11 ) are released by shear stresses generated by the cover movement. Arc furnace according to claim 5, characterized in that the recording facial expressions ( 22 ) designed as a lever and on the rotary and / or lifting portal ( 14 ) on a recording assigned to it ( 27 ) and at the second pick-up point ( 30 ) of the recording facial expressions ( 22 ) with the hydraulic cylinder ( 28 ) connected is. Arc furnace according to one or more of the preceding claims, characterized in that the rotary and / or lifting portal ( 14 ) a coolant delivery system ( 44 ), which comes in installation position from below through the rotary and / or lifting portal ( 14 ), and at least one coolant line ( 48 ) from a hydraulic cylinder ( 28 ) facing away ( 49 ) from the rotary and / or lifting portal ( 14 ) and about the recording facial expressions ( 22 ) to the furnace lid ( 13 ) and connected to these via a flange connection. Arc furnace according to claim 8, characterized in that the flange connection on the furnace cover ( 13 ) is designed as a quick coupling. Arc furnace according to one or more of the preceding claims, characterized in that the furnace lid ( 13 ) a stage level ( 43 ), which provides direct and easy access to the flange connection of the coolant supply system ( 44 ) and the cover passages ( 35 . 36 ) associated Elektrodenspannvorichtungen.

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