CA2053912A1

CA2053912A1 - Metallurgical unit

Info

Publication number: CA2053912A1
Application number: CA002053912A
Authority: CA
Inventors: Joachim Ehle; Gerhard Fuchs
Original assignee: Individual
Current assignee: Fuchs Technology AG
Priority date: 1990-02-28
Filing date: 1991-02-28
Publication date: 1991-08-29
Also published as: RU2058002C1; BR9104670A; WO1991013305A1; DE4006281A1; ZA911346B; EP0470223A1

Abstract

ABSTRACT (Figure 1) Metallurgical plant In a metallurgical plant comprising a tiltable vessel (3) which is supported on a mobile support structure (63), the vessel is fixed in a frame (61) which is supported on the support structure (63) by way of a frame lifting means (62). In that way lifting and tilting movements of the vessel can be carried out at different locations along the path of travel of the support structure and the possible variations involved in charging, tapping and maintenance of the vessel can be improved.

Description

20~3~12 ~ FUCHS TECHNOLOGY AG 90/01028 :
27 February 1990 Kr/an ,~ ' ' ' .
METALLURGICAL PLANT

The invention relates to a metallurgical plant comprising a tiltable vessel as set forth in the classifying portion of claim 1.
In a metallurgical plant of the general kind set forth, in the form of an electric arc furnace (German published specification tDE-AS~ Nb 1 758 776), a fu~nace vessel is fitted on to a mobile support structure. That structural unit can be tilted in the direction of travel of the support structure by way of a lifting means together with electrodes and an electrode holding arrangement for a slag tapping operation or for tapping off the molten metal. In that arrangement, the furnace vessel is connected to stationary mounting or support blocks by way of rotary joints to provide an axis of tilting movement, which is perpendicular to the direction of travel.
The force required to produce the tiltincl movement is applied by way of a piston-cylinder unit which is rotal:ably mounted by one end to the furnace vessel and by the other end to a stationary mounting member.
In addition, in the case of an electric arc f~lrnace with a ` support structure which is mounted movably on rails and on which the ; furnace vessel ls supported it is known ~Gen~an patent specification No 729 569) for the support structure to be moved out of a portal assenbly into a rail section, for tilting movement of the furnace vessel for a tapping operation, together with the furnace cover: the rail section can be tilted in the direction of travel by way of a lifting means together with the support structure and the furnace vessel. The portal assembly releasably carries the vessel cover and tha elect m de holder and can ia tilted in a diraction which is ';

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opposite to that involved in the tapping operation for the furnace vessel, for remo~al of slag. In addition the furnace vessel can be moved out of the portal assembly, without the vessel cover, on the support structure, in a direction which is opposite to the tiltable ~ -i5 rail section, in order that it can be charged by means of a scrap basket.
The present invention is based on the object, in a metallurgical plant of the general kind set forth, of penmitting displacement, tilting and also raising and lowering of the vessel, 10 with a simplified structure and with the involvement of a smaller -amount of time and energy. The invention further seeks to provide that the tilting and lifting movement of the vessel can be performed ~-at different locations in the w~rks buildings, to increase the possible variations involved in regard to charging, tapping material, removing slag and maintaining the vessel.
That object is attained by the characterising features of claim 1. Advantageous configurations of the invention are set forth in the -subsidiarv claims.
While in the known arrangements the vessel is supported directly on the mobile support structure and therefore the latter is included in the tilting operation, the plant according to the invention provides that the vessel is fixed in a frame which is supported on the support structure by way of a frame lifting means.
In that respect the frame lifting means is of such a design configuration that it penmits both liftmg and lowering movement of the vessel and also a tilting movement. That is possible for example by means of lifting elements which are arranged in a distributed array at the periphery of the frame and which are preferably in the ~orm of hydraulically or pneumatically actuable piston-cylinder units.
Preferably the vessel is tiltable transversely with respect to the direction of travel of the support structure. That makes it ' .
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` 2~5~912 possible to carry out tilting operations for tapping metal and removing slag directly from the usual operating position, for example the position for smelting of a charge in a smelting vessel. The vessel is possibly to be lowered slightly beforehand, by way of the frame lifting means, if the vessel cover is mounted in such a way as to be stationary.
By virtue of the lifting and tilting movements taking place between the frame and the mobile support structure, those movements can also be carried out at any position along the path of travel of the support structure, thereby increasing the possible variations involved in regard to charging, tapping, remaving slag from and maintaining the vessel, without involving additional expenditure.
Thus for example the vessel can be tapped into tw~ ladles which are arranged beside the path of travel of the vessel, if one ladle cannot accommodate the entire content of the vessel. In an emergency situation the vessel can also be moved to an emergency pit and there emptied. When the vessel is being maintained outside the operating position thereof, it can be raised, lowered and tilted, so that the operation of spraying the vessel out with refractory material can be carried out more easily. The charging options can be improved in particular in connection with a shaft which is associated with the vessel cover, as will be described in greater detail with reference to the specific embodiment. ;
The vessel can be in the form o~ a smelting vessel, for example an electric arc furnace or a reduction furnace, or it may also be a crucible furnace, a holding furnace, a converter or the like.
The invention will now be described in greater detail with reference to 7 Figures of drawings in which:
Figures 1 to 7 ara different views of a metallurgical plant in the form of a smelting plant, more sp~cifically:
Figure 1 is a side view of the smelting plant in the basic position of the vessel, :
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, :: ~ ~ . , ~" 20~3912 Figure 2 is a side view with the vessel in a displaced position, Figure 3 is a view partly in section taken along line III-III
in Figure 2, Figure 4 is a plan view of the smelting plant, Figure 5 is a plan view of the support structure of the furnace vessel, Figure 6 shows the furnace vessel in the tapping position, and Figure 7 shows the smelting plant with the vessel cover removed from the shaft.
The smelting plant shown in Figures 1 to 7 in various views and operating conditions includes an electric arc furnace 1 and a shaft-like charging material preheater 2. The arc furnace includes a furnace vessel 3 comprising a furnace hearth 4 and a vessel wall 5.
1'he furnace vessel 3 is closed with a cover 6 through which three electrodes 9 can be introduced into the furnace vessel. The electrodes 9 are carried by suppoxt arms 7 and can be raised and pivoted laterally by means of a lifting and pivoting apparatus 8.
Only one electrcde is shown in Figures l and 2, for the sake of clarity of the drawing.
The charging material preheater 2 il3 arranged laterally on the furnace vessel 3. In the lower region of the charging material preheater which extends as far as the upper edge of the vessel wall 5, the outside walls of the charging material preheater ar~ formed by the vessel wall 5. In the region thereabove the walls of the charging material preheater æ e formed by shaft l0 which is fixed in a holding structure 27. In this embodiment, the vessel cover 6 is also releasably flxed in the holding structure 27. As Figure 4 in particular shows, in plan Vi8W the furnace vessel 3 is in the form of an oval which is delimited on one side by a straight line. The straight wall portion ll together with adjoining portions 12 of the '. ,' ' ' , , ' . ' ': ' ." ' ,. ' ' ', ~ ' ' ' ' ' ' ' . " " ,~,, ., ' ' ' , `,, :, ", ' :, ' " -, . ., ' ' . . . ' ' ` ` 2~3~12 oval forms the shaft walls in the lower region of the charging material preheater.
The walls of the shaft 10 are formed by water-cooled wall elements, for reasons of weight. The cross-section of the interior 15 of the shaft 10 mcreases in a downward direction in order to ensure a trouble-free flow of the charging material 16 in the shaft L0.
In the present case the shaft 10 is of approximately rectangular shape in plan view and extends upwardly the cross-section of the charging material preheater 2, which is defined by the wall portions 11 and 12 of the furnace vessel 3. Formed between the charg~lg material preheater 2 and the electric arc furnace 1 is a connecting zone 17 which extends over the internal height and the internal width of the furnace vessel in the notional common plane between the chargmg material preheater and the arc furnace.
In the upper region the charging material preheater has a closable loading opening 18 and a gas outlet 19. l'he gas outlet 19 is connected by way of a gas pipe 20 to the chimney or a preheating chamber which is suitable for accommodating a scrap basket or container which is filled with charging material. As Figures 3 and 4 sh~w, the furnace hearth 4 has an eccentrically arranged tap hole 21.
As can be seen from Figures 3 and 4, the vessel cover 6 and the shaft 10 are mounted in a stationary condition by means of cantilever arms 59 on foundation columns 60 and the portal assembly 8. The furnace vessel 3 is fixed in an upper frame 61 which is supported on a support structure 63 by way of a frame lifting arrangement 62. The support structure 63 i5 mobile parallel to the connecting line between the centre line of the shaft and the centre of the furnace hearth, that is to say parallel to the axis 22 (see Figure 4). For that purpose, provided in the support structure on the left-hand side and on the right-hand side, in the view in Figure 1, are wheels 57 which run on rails 58.

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The furnace vessel is adapted to tilt transversely with respect to the axis 22, more specifically being tiltable for the tapping operation to one side at which there is a tap hole 21 disposed adjacent the edge of the furnace hearth 4, and being tiltable for slag removal to the other side at which there is an operating or slag opening 64, which can be closed off b~ a liftable door, with an access plate 65. In order to provide space for a ladle 66 ~hen tapping the furnace vessel (see Figure 6), the upper frame 61 is cranked upwardly at one side (see the broken line in Figure 1). On the opposite side, the upper frame 61 is cranked downwardly because of the space required for the opening 64 (see the dash-dotted line in Figure 1).
For reasons of space for the ladle 66 and a slag truck (not shown) which is to be positioned ~eneath the plate 65, the support structure 63 is also of a particular configuration. As shown in Figure 5, in plan view it has tw~ parallel transverse bearers 67 and 68 and a longitudinal bearer 69 w~lich connects the latter approximately at the centre. The runner wheels 57 are each mounted in the end regions of the transverse bearer 67 and in the central region of the transverse bearer 68, whereintwo spaced-apart wheels 57 are also provided in the central region of the transverse bearer 68. In that way ~he rails for the runner wheels of the transverse bearer 68 can also be moved into the centre so that they do not impede either the ladl0 on one side or the slag truck on the other side. In the illustrated situation the fra~e lifting arrangement 62 is formed by four lift~ng elements 70, 71 which are arranged at the periphery of the frame 61, more specifically in the region of the corners of the frame which is substantially rectangular in plan view. The lifting elements comprise hydraulically actuable piston-cylinder units.
However they could also comprise other elements such as a toothed pinion and a rack co-operating therewith, or a wDrm spindle drive.

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' ' ':' :' --` 2~.~39~2 Lifting elements are provided on both sides of the axis 22 in the illustrated embodiment, the lifting elements 71 on the tapping side are pivotable both in the frame 61 and also in the support structure 63, about axes of rotation which are parallel to the axis 22, while ; 5 on the slag side (left-hand side in Figure 3) the lifting elements 70involve a vertical guide configuration and are only mounted pivotably in the upper frame 61, about an axis of rotation which is parallel to the axis 21. The lifting elements 70 and the lifting ele~ents 71 are each synchronously controllable. The furnace vessel can be tilted on to one side for tapping metal therefrom, by synchronous lowering movement of the lifting elements 71, while the furnace vessel can be tilted on to the other side for lemoving slag by synchronous lowering movement of the lifting elements 70. If all the lifting elements are lowered synchronously, the furnace vessel 3 can be lowered without tilting.
In the illustrated embodiment the vertical guide configuration for the lifting elements 70 is provided by the fact that the hydxaulic cylinders are held in tubes 72 which are fixedly connected ~ to the support structure 63.
; 20 The following process steps can be carried out with the above-described smelting plant.
After the operation of tapping off a molten metal bath (Figure 6), for which purpose the lifting elements 71 æ e lowered, and the furnace vessel 3 is tilted about the upper axes of r~tation of the fixed lifting el~ments 70, the lifting elements 71 are lifted again to a position in which there is still a sufficient spacing relative to the lowex edge of the vessel cover 6 so that the furnac~ vessel 3 can be displaced horizontally. In that position the support structure is moved towards the left from the position shown in Figure 1 until either the entire vessel is disposed outside the region of the shaft 10 in order for charging material to be introduced directly into the . . . . .

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.:: , vessel from a scrap basket, or only into a position as shown in Figure 2 in order for charging material to be introduced frcm a charging material container 73 by way of the shaft 10 into the right-hand half of the furnace vessel, that is to say the half of the vessel which is on the side of the electrode lifting arrangement.
That position is shown in dash-dotted lines in Figure 4. In order in that position to prevent environmental pollution due to furnace gases escaping from the left-hand half of the vessel, it is possible to provide, in horizontal alignment with the vessel cover ttowards the left in Figure 2), a cover means ~not shown), for example a cover plate which is aligned with the lower edge of the vessel cover and which is secured thereto or in some other fashion.
~ m e furnace vessel is then moved back into the starting position shown in Figure l and lifted to such an extent as to ensure the desired closure effect as between the furnace vessel and the vessel cover. In that position further charging material is introduced through the shaft 10: in that operation, a column of scrap is built up in the shaft, being supported at the bottom of the vessel and in the left-hand region of the vessel wall. After closure of the " ~l shaft cover 74 which is of the cross-section shown in Figure 1 in the form of an inverted U-shape and which is horizontally displaceable on rails 75, the next furnace charge is smelted, during which oFeration the column of scrap is subjected to a pre-heating effect by the furnace gases which are produced.
It will be appreciated that the horizontal mobility of the i furnace vessel also makes it possible, during the smelting process, for the electric arc electrodes to be ~oved closer to the column of charging material in order to expedite the smelting process at that -- location. Partial opening of the vessel, which occurs as a result of that m~de of operation, can be avoided by the provision here too of a cover meens discossd horizontally in line with the e~ge of the vsssel .~ ` '.

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cover (towards the right in Figure 2). The discharge of furnace gases can be retarded in the tapping operation (see Figure 6) for ex~"~le -~by a chain apron or skirt 76. However the gases which issue in the tilting operation can also bs sucked away by a stationary collecting hood.
The structural association of the shaft 10 with the furnace vessel cover 6 does not mean that the shaft must be non-releasably connected to the vessel cover. On the contrary it is desirable for the cover to be replaceable, in the event of damage. For that reason, `10 in the embodiment illustrated in Figures 1 to 7, the vessel cover 6 is releasably fixed in the holding structure 27 of the shaft, which ,is supported on the foundation columns 60, so that, after that fixing arrangement has been released, as shown in Figure 7 , the vessel cover can bs lowered in such a way as to lie on the upper edge of the vessel, by sinultaneous lowering movement of the lifting elements, and can be moved with the furnace vessel out of the region o-E the shaft 10 (towards the left in the view shown in Figure 1), and can be removed and replaced, by means of a crane.

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Claims

1. A metallurgical plant comprising a tiltable vessel (3) which is supported on a mobile support structure (63) characterised in that the vessel (3) is fixed in a frame (61) which is supported on the support structure (63) by way of a frame lifting means (62).

2. A metallurgical plant according to claim 1 characterised in that the vessel (3) is tiltable transversely with respect to the direction of movement of the support structure (63).

3. A metallurgical plant according to claim 1 or claim 2 characterised in that the frame lifting means (62) is formed by at least three lifting elements (70, 71) which are arranged in a distributed array at the periphery of the frame (61).

4. A metallurgical plant according to claim 3 characterised in that the lifting elements (70, 71) are formed by hydraulically or pneumatically actuable piston-cylinder units.

5. A metallurgical plant according to claim 3 or claim 4 characterised in that the lifting elements (70, 71) are disposed on both sides of a centre line (22) of the vessel, which is parallel to the direction of travel of the support structure (63), and the lifting element or elements (71) at one side are mounted pivotably about axes of rotation which are parallel to the line (22), both in the frame (61) and also in the support structure (63), while the lifting element or elements on the other side have a vertical guide means (72).

6. A metallurgical plant according to one of claims 1 to 5 characterised in that the support structure (63) comprises two parallel transverse bearers (67, 68) and a longitudinal bearer (69) which connects same approximately at the centre.

7. A metallurgical plant according to one of claims 1 to 6 characterised in that the longitudinal bearer (69) extends parallel to the line (22).

8. A metallurgical plant according to one of claims 5 to 7 characterised in that the frame (61) is of substantially rectangular configuration in plan view and the lifting elements (70, 71) are respectively arranged in the regions of the corners of said frame.

9. A metallurgical plant according to one of claims 6 to 8 characterised in that the support structure (63) has respective wheels (57) in the end regions of the one transverse bearer (67) and in the central region of the other transverse bearer (68).

10. A metallurgical plant according to one of claims 1 to 9 characterised in that the vessel (3) is a smelting vessel having a tap hole (21) or a tap nozzle arranged in the edge region transversely with respect to the centre line (22) of the vessel.

11. A metallurgical plant according to claim 10 characterised in that the vessel (3) has an operating or slag opening (64) on the side opposite to the tap hole (21) or nozzle.

12. A metallurgical plant according to claim 11 characterised in that the frame (61) is cranked upwardly on the tapping side of the vessel and downwardly on the side of the slag opening (64).

13. A metallurgical plant according to one of claims 1 to 12 characterised in that the vessel (3) is closable by a vessel cover (6) which is fixed releasably in a stationary holding means (27).