REMELTING PLANT FOR METALS, AND METHOD FOR REMELTING METALS

Abstract

The present invention relates to remelting plants, such as for example vacuum arc remelting furnaces (VLBO/VAR) and electro slag remelting plants (ESU/ESR), which possess one or several melting sites and have a portal structure. The plants possess a symmetric force distribution and a constantly low height of construction.

Claims

1. A remelting plant for metals comprising one or several melting sites, which for the most part are arranged in the underground in a foundation of the remelting plant, with one crucible each; a furnace portal comprising a first and a second vertical column, which are connected on their upper end with two opposing sides of a horizontal connecting frame and along their height with at least one further frame formed by two brackets, wherein the furnace portal with the first vertical column is connected with the foundation such that it can be rotated, and with the second vertical column, a lower end of which is provided with a drive and at least one wheel, can be moved on a curved rail, so that the furnace portal can make a swiveling movement over the one or several melting sites; a one-piece furnace chamber, which is open on its lower side and which can be vertically moved within the frame being formed by the two brackets; openings, which are arranged on sides of the connecting frame, which are not connected with the vertical columns; a plurality of locking elements, which are provided on the brackets and which are able to fix the furnace chamber in the vertical; a balance, which with its lower side is connected with an upper side of the furnace chamber; an electrode rod supporting structure comprising two columns with variable lengths, a lower plate being attached on their lower end and an upper plate being attached on their upper end, wherein the lower plate is connected with the balance and the upper plate is engaged with the openings of the connecting frame and can be moved vertically within them; and an electrode rod, which runs through the lower plate and the upper plate, with a coaxial electrode rod drive, which is fastened on the upper plate, wherein the electrode rod comprises an outer tube, an inner tube being movable therein and a spindle being arranged in the inner tube, and the electrode rod drive drives the spindle inside of the electrode rod.

2. The remelting plant according to claim 1, wherein a connection of the first vertical column with the foundation, which is such that a rotational movement is possible, is realized by a large-diameter slewing ring bearing.

3. The remelting plant according to claim 1, wherein the balance is designed as a gimbal frame on two weighing cells.

4. The remelting plant according to claim 1, wherein the upper plate is connected with the frame via two horizontally acting drives being arranged orthogonally to each other.

5. A method for remelting metals in a remelting plant according to claim 1 comprising the steps of: a) positioning of the furnace portal over one of the melting sites; b) lifting of the furnace chamber into a lifted position by retracting of the two columns with variable lengths of the electrode rod supporting structure, wherein the upper plate is supported on lower rims of the openings of the connecting frame, locking of the locking elements on the brackets, and extending of the two columns with variable lengths by a length, which is smaller than the height of the openings, so that the upper plate is no longer supported on the lower rims of the openings and the furnace chamber rests on the locking elements; c) fastening of an electrode made of the metal which has to be remelted on the electrode rod; d) placing of the furnace chamber on the crucible by retracting of the two columns with variable lengths of the electrode rod supporting structure by a length, which is smaller than a height of the openings of the connecting frame, so that the upper plate again is supported on the lower rims of the openings and the furnace chamber no longer rests on the locking elements on the brackets, unlocking of the locking elements on the brackets, and extending of the two columns with variable lengths, until the furnace chamber rests on the crucible; e) extending of the two columns with variable lengths by a length, which is smaller than the height of the openings of the connecting frame, so that the upper plate is no longer supported on the lower rims of the openings, and arresting of the two columns with variable lengths; f) remelting of the electrode under application of a voltage and repositioning of the electrode by extending of the electrode rod; g) opening of the crucible by repeating of step b) and removal of a remelted metal.

6. The method for remelting according to claim 5, wherein in step c) the electrode made of the metal which has to be remelted, which is clamped on the electrode rod, is centered in the furnace chamber by means of the horizontally acting drives.

7. A method for remelting metals in a remelting plant according to claim 2 comprising the steps of: a) positioning of the furnace portal over one of the melting sites; b) lifting of the furnace chamber into a lifted position by retracting of the two columns with variable lengths of the electrode rod supporting structure, wherein the upper plate is supported on lower rims of the openings of the connecting frame, locking of the locking elements on the brackets, and extending of the two columns with variable lengths by a length, which is smaller than the height of the openings, so that the upper plate is no longer supported on the lower rims of the openings and the furnace chamber rests on the locking elements; c) fastening of an electrode made of the metal which has to be remelted on the electrode rod; d) placing of the furnace chamber on the crucible by retracting of the two columns with variable lengths of the electrode rod supporting structure by a length, which is smaller than a height of the openings of the connecting frame, so that the upper plate again is supported on the lower rims of the openings and the furnace chamber no longer rests on the locking elements on the brackets, unlocking of the locking elements on the brackets, and extending of the two columns with variable lengths, until the furnace chamber rests on the crucible; e) extending of the two columns with variable lengths by a length, which is smaller than the height of the openings of the connecting frame, so that the upper plate is no longer supported on the lower rims of the openings, and arresting of the two columns with variable lengths; f) remelting of the electrode under application of a voltage and repositioning of the electrode by extending of the electrode rod; g) opening of the crucible 2 by repeating of step b) and removal of a remelted metal.

8. The method for remelting according to claim 7, wherein in step c) the electrode made of the metal which has to be remelted, which is clamped on the electrode rod, is centered in the furnace chamber by means of the horizontally acting drives.

9. A method for remelting metals in a remelting plant according to claim 3 comprising the steps of: a) positioning of the furnace portal over one of the melting sites; b) lifting of the furnace chamber into a lifted position by retracting of the two columns with variable lengths of the electrode rod supporting structure, wherein the upper plate is supported on lower rims of the openings of the connecting frame, locking of the locking elements on the brackets, and extending of the two columns with variable lengths by a length, which is smaller than the height of the openings, so that the upper plate is no longer supported on the lower rims of the openings and the furnace chamber rests on the locking elements; c) fastening of an electrode made of the metal which has to be remelted on the electrode rod; d) placing of the furnace chamber on the crucible by retracting of the two columns with variable lengths of the electrode rod supporting structure by a length, which is smaller than a height of the openings of the connecting frame, so that the upper plate again is supported on the lower rims of the openings and the furnace chamber no longer rests on the locking elements on the brackets, unlocking of the locking elements on the brackets, and extending of the two columns with variable lengths, until the furnace chamber rests on the crucible; e) extending of the two columns with variable lengths by a length, which is smaller than the height of the openings of the connecting frame, so that the upper plate is no longer supported on the lower rims of the openings, and arresting of the two columns with variable lengths; f) remelting of the electrode under application of a voltage and repositioning of the electrode by extending of the electrode rod; g) opening of the crucible 2 by repeating of step b) and removal of a remelted metal.

10. The method for remelting according to claim 9, wherein in step c) the electrode made of the metal which has to be remelted, which is clamped on the electrode rod, is centered in the furnace chamber by means of the horizontally acting drives.

11. A method for remelting metals in a remelting plant according to claim 4 comprising the steps of: a) positioning of the furnace portal over one of the melting sites; b) lifting of the furnace chamber into a lifted position by retracting of the two columns with variable lengths of the electrode rod supporting structure, wherein the upper plate is supported on lower rims of the openings of the connecting frame, locking of the locking elements on the brackets, and extending of the two columns with variable lengths by a length, which is smaller than the height of the openings, so that the upper plate is no longer supported on the lower rims of the openings and the furnace chamber rests on the locking elements; c) fastening of an electrode made of the metal which has to be remelted on the electrode rod; d) placing of the furnace chamber on the crucible by retracting of the two columns with variable lengths of the electrode rod supporting structure by a length, which is smaller than a height of the openings of the connecting frame, so that the upper plate again is supported on the lower rims of the openings and the furnace chamber no longer rests on the locking elements on the brackets, unlocking of the locking elements on the brackets, and extending of the two columns with variable lengths, until the furnace chamber rests on the crucible; e) extending of the two columns with variable lengths by a length, which is smaller than the height of the openings of the connecting frame, so that the upper plate is no longer supported on the lower rims of the openings, and arresting of the two columns with variable lengths; f) remelting of the electrode under application of a voltage and repositioning of the electrode by extending of the electrode rod; g) opening of the crucible 2 by repeating of step b) and removal of a remelted metal.

12. The method for remelting according to claim 11, wherein in step c) the electrode made of the metal which has to be remelted, which is clamped on the electrode rod, is centered in the furnace chamber by means of the horizontally acting drives.

Description

SHORT DESCRIPTION OF THE FIGURES

[0056] FIG. 1 is a perspective view of a remelting plant according to the present invention in accordance with the ESU method in the closed state during melting.

[0057] FIG. 2 is a perspective view of a remelting plant according to the present invention in accordance with the VLBO method in the closed state during melting.

[0058] FIG. 3 is a sectional view of the remelting plant of FIG. 1 in the opened state prior to melting.

[0059] FIG. 4 is a perspective view of the balance with a gimbal frame.

[0060] FIG. 5 is a perspective view of the connecting frame with the upper plate for the electrode rod supporting structure.

[0061] FIG. 6 is a sectional view of the connecting frame with the upper plate for the electrode rod supporting structure.

DESCRIPTION OF THE FIGURES

[0062] The figures only show a preferred design variant as an example for the invention. Therefore, they should not be construed as limiting. In particularly, they show useful combinations of features, which, however, can also be used singly or in other combinations.

[0063] FIG. 1 shows a perspective view of a remelting plant according to the present invention in accordance with the ESU method in the closed state during melting. In this example presented the remelting plant comprises two melting sites (1). The melting sites (1) are provided in the foundation of the plant. The melting sites (1) contain a melting crucible (2), in which the melting process takes place. A furnace portal (3) consisting of two vertical columns (4) being arranged parallel to each other is fastened in a swiveling manner on the foundation of the plant.

[0064] One of both vertical columns (4) is fastened on the foundation in a rotating manner via a large-diameter slewing ring bearing (7), the opposite vertical column (4) comprises on its lower end a drive (5) with wheel (6), which rests on a curved rail (8) on the foundation. On their upper ends the vertical columns (4) are connected by a rectangular connecting frame (9) with each other. Furthermore, approximately at 40% of the portal height the vertical columns (4) are once again connected via two brackets (10), which form a further closed frame.

[0065] Between both vertical columns (4) in the frame being formed by the brackets (10) a one-piece furnace chamber (11) which is open on its lower side is provided, on which a balance (12) rests. On the balance (12), which is designed as a gimbal frame (13) on two weighing cells (14), a lower plate (15) of a frame-like electrode rod supporting structure (16) is fastened. This electrode rod supporting structure (16) consists, in turn, of two vertical columns (17) with variable lengths and an upper plate (18), on which the electrode rod drive (20) with the electrode rod (19) is fastened. Here, the vertical columns (17) with variable lengths of the electrode rod supporting structure (16) are provided as driven telescope-like structures in the form of hydraulic cylinders. The upper plate (18) with the electrode rod drive (20) is installed in two lateral openings (21) in the girders forming the connecting frame (9) such that it is protected against lifting off upwards and that in the case of a minimum movement downwards it rests on the lower rims of these openings (21).

[0066] In addition, the upper plate (18) is connected via two horizontally acting drives (22) which are arranged orthogonally to each other with the girders of the frame (9). In the presentation of FIG. 1, the second drive (22) can only be seen partly, because in viewing direction it is arranged behind the electrode rod drive (20). In both brackets (10) connecting the vertical columns (4) cylindrical bolts as locking elements (23) are installed, which serve for supporting the furnace chamber (11), when it is lifted.

[0067] FIG. 2 shows a perspective view of a remelting plant according to the present invention in accordance with the VLBO method in the closed state during melting. In the case of this plant the whole upper plant section is identical to the plant in accordance with the ESU method of FIG. 1. Only the melting site (1) is different, which is correspondingly designed for the VLBO method. In FIG. 2 only one of the melting sites (1) is shown.

[0068] FIG. 3 shows a sectional view of the remelting plant of FIG. 1 in the opened state prior to melting. The section runs vertically exactly through the center of the plant. The two vertical columns (17) with variable lengths of the electrode rod supporting structure (16) are retracted. The furnace chamber (11) hangs in the upper position and it is arrested by means of the locking elements (23). Here, the lower rim of the furnace chamber (11) is positioned a little bit below the height of the brackets (10). In the crucible (2) already the new electrode (24) which has to be remelted is inserted, which is then clamped with its stub (25) onto the electrode rod clamp (26). The double tube structure of the electrode rod (19) with the spindle inside can well be seen. Via this spindle the electrode rod clamp (26) is lowered in an extent such that the stub (25) can be grasped. Subsequently, the electrode rod (19) is retracted again, so that the electrode (24) hangs freely and can be adjusted.

[0069] It can also be seen that in this position the upper plate (18) rests on the lower rim of the lateral openings (21) in the girders of the connecting frame (9).

[0070] FIG. 4 shows a perspective view of the balance (12) with the gimbal frame (13) of the remelting plant being in the closed melting position. In this presentation of a detailed section can be seen, how the electrode rod (19) runs through the upper plate (15) and the vacuum-tight bushing (27) into the furnace chamber (11). The lower plate (15) is connected with the gimbal frame (13) of the balance (12) via the joint (28). The second joint direction of the gimbal frame (13) form the weighing cells (14). During retracting of the columns (17) with variable lengths the furnace chamber (11) with the vacuum-tight bushing slides upwards on the electrode rod (19), guided by the lower plate (15). When the upper plate (18) by means of the drives (22) is moved for aligning the electrode (24) in the crucible (2), and so the electrode rod (19) is tilted, then this movement can be compensated by the gimbal frame (13) via the joints (28) and the weighing cells (14).

[0071] FIG. 5 shows a perspective view of the connecting frame (9) with the upper plate (18) for the electrode rod supporting structure (16). Now, in the view obliquely from above, both horizontally acting drives (22) which are arranged orthogonally to each other can be seen better. In this example they are hydraulic cylinders. In the center of the upper plate (18) on the yoke (29) of the electrode rod (19) the electrode rod drive (20) is located. The upper plate (18) engages with the openings (21) of the connecting frame (9).

[0072] FIG. 6 shows a sectional view of the connecting frame (9) with the upper plate (18) for the electrode rod supporting structure (16). The sectional view shows well the double tube structure of the electrode rod (19) and the spindle (30) being arranged in it, which is connected with the upper end of the inner tube of the electrode rod (19) via the spindle nut (31). In this view also the fastening of the spindle (30) in the yoke (29) on the electrode rod drive (20) can be seen.

LIST OF REFERENCE SIGNS

[0073]

TABLE-US-00001 1 melting site 2 crucible 3 furnace portal 4 vertical column 5 drive 6 wheel 7 large-diameter slewing ring bearing 8 rail 9 connecting frame 10 bracket 11 furnace chamber 12 balance 13 gimbal frame 14 weighing cell 15 lower plate 16 electrode rod supporting structure 17 column with variable lengths 18 upper plate 19 electrode rod 20 electrode rod drive 21 opening 22 drive 23 locking element 24 electrode 25 stub 26 electrode rod clamp 27 bushing 28 joint 29 yoke 30 spindle 31 spindle nut