METHOD AND SYSTEM FOR COMPENSATING FOR ELECTRODE BURN-OFF IN AN ARC FURNANCE

Abstract

A method (100) and a system (1) for compensating for an electrode (2) burn-off in an arc furnace (3) in which at least a part of the electrode (2) held in a first retaining position (H1) by a retaining device (4) is detected (Si) with the aid of a sensor device (5) and a second retaining position (H2) is determined (S2) on the basis of data generated during the detection. The retaining device (4) can then be repositioned (S4) relative to the electrode (2) from the first retaining position (H1) to the determined second retaining position (H2).

Claims

1. A method to compensate for the burn-off of an electrode in an electric arc furnace, having the steps: detecting (S1) at least an upper electrode end and a holding position (H1) of the electrode held by a holding apparatus with the aid of a sensor apparatus; determining (S2) a first distance (D2) on the basis of the data generated during the detection, the first distance (D2) being determined between an upper electrode end and the first holding position (H1), a second holding position (H2) is determined on the basis of at least the first distance (D2), a predetermined connecting position (V) at which two segments (E1, E2) of the electrode are connected to one another, and a predetermined connecting region (B), verifying that the electrode is being supported on a supporting apparatus, and repositioning (S4) the holding apparatus relative to the electrode from the first holding position (H1) to the second holding position (H2) which has been determined.

2. The method as claimed in claim 1, wherein, a first distance (D2) between an upper electrode end and a marking applied on the electrode is determined on the basis of the data generated during the detection, and the determination of the second holding position (H2) is based thereon.

3. The method as claimed in claim 1, wherein, the data generated during the detection contain a profile (A) of a horizontal distance (D1) between the electrode and/or the holding apparatus on the one hand, and the sensor apparatus on the other hand, and the second holding position (H2) is determined on the basis of the profile (A).

4. The method as claimed in claim 1, wherein, a pressure signal or an optical sensor device is used to verify that the electrode is being supported on the supporting apparatus before the holding apparatus is repositioned from the first holding position (H1) to the second holding position (H2).

5. The method as claimed in claim 1, wherein, a residual length of the electrode is determined on the basis of the data generated during the detection and is output (S3).

6. The method as claimed in claim 7, wherein, the residual length is determined on the basis of a second distance between the first holding position (H1) and the supporting apparatus.

7. The method as claimed in claim 7, wherein, the residual length of the electrode which has been determined is checked after each melting cycle in the electric arc furnace and the second holding position (H2) is determined as a function of a result of the check.

8. The method as claimed in claim 1, wherein, the electrode is displaced vertically with the aid of the holding apparatus in order to detect at least a part of the electrode.

9. The method as claimed in claim 1, wherein, the sensor apparatus is displaced vertically with the aid of a supporting apparatus in order to detect the at least one part of the electrode.

10. The method as claimed in claim 1, wherein, at least a part of the electrode is detected several times in succession and the second holding position (H2) is determined on the basis of averaging the data thereby respectively generated.

11. The method as claimed in claim 1, wherein, a measure of the reliability of the data generated during the detection is determined during the detection of at least a part of the electrode.

12. The method as claimed in claim 1, wherein, the sensor apparatus has a camera or a laser sensor, with which at least a part of the electrode is detected.

13. The method as claimed in claim 1, wherein, a number of a plurality of electrodes are held with the aid of the holding apparatus, and the sensor apparatus has a corresponding number of laser sensors with which at least a part of one of the electrodes is respectively detected.

14. A system to compensate for the burn-off of an electrode in an electric arc furnace, having: a holding apparatus, which is adapted to hold the electrode at a first holding position (H1); a sensor apparatus, which is adapted to detect at least a region from an upper electrode end as far as the first holding position (H1); a processing apparatus, which is adapted to verify that the electrode is being supported on a supporting apparatus, the processing apparatus furthermore being adapted to determine a second holding position (H2) on the basis of the data generated during the detection, at least the upper electrode end and the first holding position (H1) being contained in the generated data, as well as of a predetermined connecting position (V) at which two segments (E1, E2) of the electrode are connected to one another, and of a predetermined connecting region (B); and a control apparatus, which is adapted to induce repositioning of the holding apparatus relative to the electrode from the first holding position (H1) to the second holding position (H2) which has been determined.

15. A system to compensate for the burn-off of an electrode in an electric arc furnace as claimed in claim 14, wherein, a number of a plurality of electrodes are held with the aid of the holding apparatus, and the sensor apparatus has a corresponding number of laser sensors and/or cameras.

16. A system to compensate for the burn-off of an electrode in an electric arc furnace as claimed in claim 14, wherein, the sensor apparatus has a camera or a laser sensor.

17. A system to compensate for the burn-off of an electrode in an electric arc furnace as claimed in claim 14, wherein, the processing apparatus is adapted to verify with the aid of a signal of a pressure measuring apparatus or by data of the sensor device that the electrode is being supported on the supporting apparatus, before the holding apparatus is repositioned from the first holding position (H1) to the second holding position (H2).

Description

BRIEF DESCRIPTION OF THE FIGURES

[0047] At least partially schematically:

[0048] FIG. 1 shows an example of a system to compensate for the burn-off of three electrodes in an electric arc furnace in a plan view;

[0049] FIG. 2 shows an example of a system to compensate for the burn-off of an electrode in an electric arc furnace in a side view;

[0050] FIG. 3 shows an example of a profile of the horizontal distance between an electrode and a sensor apparatus; and

[0051] FIG. 4 shows an example of a method to compensate for the burn-off of an electrode in an electric arc furnace.

DETAILED DESCRIPTION

[0052] FIG. 1 shows an example of a system 1 to compensate for the burn-off of three electrodes 2 in an electric arc furnace 3 in a plan view. The electrodes 2 are respectively held by a holding apparatus 4 of the system 1, preferably vertically as represented in FIG. 1, in a first holding position. Vertical holding is in this case intended to mean holding in which a longitudinal axis of each electrode 2 is aligned vertically.

[0053] Besides the holding apparatus 4, the system 1 also has a supporting apparatus 5, which is adapted respectively to detect at least a part of the electrodes 2 being held, as well as a processing apparatus 6 which is adapted to determine a second holding position on the basis of the data generated during the detection, in particular for each of the electrodes 2. A control apparatus 7 of the system 1 is adapted to induce repositioning of the holding apparatus 4 relative to the electrodes 2 from the first holding position to the second holding position which has been determined, for example by corresponding driving of the holding apparatus 4.

[0054] With the aid of the holding apparatus 4, the vertically held electrodes 2, in particular the lower electrode ends, can be positioned in a vessel 8 of the electric arc furnace 3, where they can be inserted at least partially into a melting stock and can cause the latter to melt by flow of current. The holding apparatus 4 for this purpose has a lifting unit 4a with which the electrodes 2 can be displaced vertically, that is to say lifted and/or lowered perpendicularly with respect to the plane of the drawing.

[0055] With the aid of the holding apparatus 4, the electrodes 2 can preferably also be moved out from the vessel 8 and positioned by means of a supporting apparatus 9, which is preferably arranged externally next to the electric arc furnace 3, for example adjacent to the vessel 8. For example, carrying arms 4b of the holding apparatus 4 can be tilted horizontally, that is to say in the plane of the drawing, until the electrodes 2 are positioned over the supporting apparatus 9. From this position, indicated by dashes, the electrodes 2 may be lowered onto the supporting apparatus 9 with the aid of the lifting device 4a. As an alternative, the electrodes 2 may also be supported by lifting the supporting apparatus 9, for instance with the aid of a corresponding lifting device.

[0056] The supporting apparatus 9 and the sensor apparatus 5 are in this case preferably arranged relative to one another in such a way that the sensor apparatus 5 has a free or unobstructed field of view of the electrodes 2 supported by the supporting apparatus 9, or at least positioned above the supporting apparatus 9. A sensor apparatus 5, for example configured as a camera, may therefore reliably detect the electrodes 2 at least partially, or in sections.

[0057] In the exemplary embodiment shown, instead of a camera, the sensor apparatus 5 has a plurality of, namely three laser sensors 11, which are respectively adapted to detect, in particular to sample or scan, at least a part or section of one of the three electrodes 2 with the aid of a laser beam 12. If the sensor apparatus 5 does not have, or if the laser sensors 11 do not have, means for tilting the laser beams 12, for example in the form of tiltable mirrors, it is conceivable to provide a sensor lifting apparatus 10. With the aid of the latter, the sensor apparatus 5, or the laser sensors 11, may advantageously be displaced at least vertically in order to detect the electrodes 2 respectively from an upper electrode end at least as far as the first holding position.

[0058] As an alternative, it is however also possible that, in order to detect the regions between the upper electrode ends and the first holding positions, the electrodes 2 are displaced vertically with the aid of the holding apparatus 4, in particular the lifting unit 4a, before they are supported by the supporting apparatus 9.

[0059] Once the processing device 6 has then determined the second holding position on the basis of the data generated during the detection of the electrodes 2, the control apparatus 7 may induce the holding apparatus 4 to loosen or at least partially open clamping or gripping units 4c of the holding apparatus 4, which hold the electrodes 2, for example by gripping, so that the electrodes 2 are mobile relative to the gripping units 4c. The control apparatus 7 may then induce the holding apparatus 4, in particular the lifting unit 4a, or as an alternative the supporting apparatus 9, to be displaced vertically so that the gripping units 4c are positioned at the height of the second holding position.

[0060] Subsequently, the control apparatus 7 drives the holding apparatus 4, in particular the gripping units 4c, preferably in such a way that the gripping units 4c close again and are held firmly at the second holding position by the electrodes 2.

[0061] It is also conceivable to position the sensor apparatus 5 in such a way that the electrodes 2 can already be detected at least partially, or in sections, in particular from their upper electrode end as far as the first holding position, when the electrodes 2 are still located above the electric arc furnace 3, or the vessel 8, particularly in an operating position. In this way, the second holding position may be determined and repositioning of the holding apparatus 4, in particular of the gripping units 4c, relative to the electrodes 2 may also possibly be carried out without the electrodes 2 having to be tilted horizontally, possibly even without the electrodes 2 having to be lifted out from the electric arc furnace 3, or the vessel 8.

[0062] FIG. 2 shows an example of a system 1 to compensate for the burn-off of an electrode 2 in an electric arc furnace in a side view. The system 1 has a holding apparatus 4 to hold the electrode 2 at a first holding position H1 as well as a sensor apparatus 5 to detect at least a part of the electrode 2 being held. The system 1 furthermore has a processing apparatus 6 to determine a second holding position H2 on the basis of the data generated during the detection, as well as a control apparatus 7 to induce repositioning of the holding apparatus 4 relative to the electrode 2 from the first holding position H1 to the second holding position H2 which has been determined.

[0063] As represented in FIG. 2, the holding apparatus 4 in this case holds the electrode 2 vertically, that is to say in such a way that a longitudinal axis L of the electrode 2 is aligned perpendicularly.

[0064] In the example shown, the processing apparatus 6 and the control apparatus 7 are configured as software modules, which may for example be executed by a working means 13. The working means 13 may for example be a computer, in particular a personal computer, a programmable logic controller, an (application-specific) integrated circuit (ASIC) and/or the like.

[0065] The holding apparatus 4 comprises a carrying arm 4b, on the end of which facing toward the electrode 2 a gripping unit 4c, for example a clamping jaw, is arranged. With the aid of the gripping unit 4c, the electrode 2 can be gripped and held. If the gripping unit 4c loosens its grip, the holding apparatus 4 can be repositioned relative to the electrode 2, for instance by the electrode being supported statically by a supporting apparatus (not shown) at a lower electrode end (not shown) and the holding apparatus 4 being lifted.

[0066] In the example shown, the sensor apparatus 5 is configured as a laser sensor 11, which emits a laser beam 12. With the aid of the laser beam 12, the electrode 2 may be sampled, in particular from its upper electrode end 2a at least as far as the first holding position H1, or as far as the gripping unit 4c. For this purpose, the laser beam 12 may be tilted, for instance with the aid of a tiltable mirror. As an alternative, the sensor apparatus 5 and the electrode 2 may be moved relative to one another, for instance by the electrode 2 being lifted, or displaced, in the direction of the laser beam 12 with the aid of the holding apparatus 4. This is indicated by the arrow P.

[0067] The data generated during the detection with the aid of the laser sensor 11 may then contain a profile of the horizontal distance D1 between the electrode 2 and the sensor apparatus 5. For example, a first (vertical) distance D2 between the upper electrode end 2s and the first holding position H1, in particular the holding apparatus 4 or the gripping unit 4c, may be derived from this distance profile. The second holding position H2, namely between the upper electrode end 2a and the first holding position H1, may be established on the basis of the distance profile or of the first distance D2 derived therefrom.

[0068] The determination of the second holding position H2 is preferably also based on a predetermined connecting position V, at which segments E1, E2 of the electrode 2 are connected to one another, for example screwed to one another. The second holding position H2 is preferably selected in such a way that it does not overlap with the predetermined connecting position V, or a connecting region B indicated by hatching in FIG. 2 around this connecting position V, or does not fall within this connecting region B. In this way, it is possible to prevent the electrode 2, in particular a connecting means used to connect the electrode segments E1, E2, from being damaged during holding by the holding apparatus 4, for example by the exertion of a pressure with the gripping unit 4c.

[0069] FIG. 3 shows an example of a profile A of the horizontal distance D1 between an electrode held by a holding apparatus at a first holding position H1, on the one hand, and on the other hand a sensor apparatus with which at least a part, or section, of the electrode is detected, for example by displacing the sensor apparatus and the electrode or the holding apparatus relative to one another. The profile A is also referred to as a distance profile and is obtained by plotting the horizontal distance D1 against a displacement path z of the sensor apparatus and electrode, or holding apparatus, relative to one another.

[0070] The distance profile A preferably images the shape, or contour, of the electrode being held and of at least a part of the holding apparatus. In the distance profile A, for example, an upper electrode end 2a and a gripping unit 4c gripping the electrode may be seen. The location of the gripping unit 4c also gives the location of the first holding position H1 relative to the upper electrode end 2a, and therefore in particular a first (vertical) distance D2 between the upper electrode end 2a and the first holding position H1.

[0071] On the basis of the distance profile A, it is therefore possible to determine a second holding position (see FIG. 2), which preferably lies between the upper electrode end 2a and the first holding position H1. If the length of segments of which the electrode is composed is furthermore known, starting from the upper electrode end 2a it is possible to deduce predetermined connecting positions at which the segments are connected to one another. If the first distance D2 determined on the basis of the distance profile A is greater than the previously known segment length, the electrode section still available, in which the electrode may be held, may be determined by subtracting the (axial) length of a connecting region around the predetermined connecting position from the first distance D2, and the second holding position may be established on the basis thereof.

[0072] FIG. 4 shows an example of a method 100 to compensate for the burn-off of an electrode in an electric arc furnace.

[0073] In a method step S1, at least a part of the electrode held by a holding apparatus at a first holding position is detected with the aid of a sensor apparatus. For this purpose, the electrode may be sampled, or scanned, at least in sections, particularly in a region at its upper end, for example with the aid of a laser sensor.

[0074] The data thereby generated, for example a profile of a horizontal distance between the electrode and/or the holding apparatus, on the one hand, and of the sensor apparatus on the other, are used as a basis in a second method step S2 in order to determine a second holding position. For this purpose, a first, in particular vertical, distance between the upper electrode end and the holding apparatus, or the first position, may be derived on the basis of data, in particular from distance profile. This first distance determined in this way corresponds to a section of the electrode in which holding of the electrode is still possible.

[0075] Optionally, a predetermined connecting position, at which segments of electrode are connected to one another, may also be taken into account during the determination of the second holding position, in particular of the first distance. For example, an axial extent or length (“axial” referring to a direction parallel to a longitudinal axis of the electrode) of a connecting region around the connecting position may be subtracted from the first distance which has been determined, in order to obtain a “cleaned” remaining section in which holding of the electrode is possible.

[0076] In a further method step S3, the electrode may then be supported with the aid of a supporting apparatus, that is to say braced thereon. In order to verify the support, or bracing, a pressure signal may in this case be detected, which is generated for example by a pressure sensor assembly installed in the supporting apparatus or in a hydraulic assembly for lifting and lowering the supporting apparatus. From the relative positioning of the holding apparatus and the supporting apparatus which exists at the instant of the detection of the pressure signal, which may for example be detected with the aid of position encoders of the holding apparatus or of the supporting apparatus, as well as from the first distance which has been determined between the upper electrode end and the first holding position, or the holding apparatus, a remaining overall length of the electrode may then be deduced, and this may for example be output to a user.

[0077] Subsequently, in a further method step S4, the holding apparatus may be repositioned relative to the electrode, specifically in such a way that the holding apparatus then holds the electrode at the second holding position which has been determined. For this purpose, a gripping unit, for example a clamping jaw, which holds the electrode, of the holding apparatus is preferably first loosened. Subsequently, the holding apparatus and the supporting apparatus, and therefore also the electrode being supported, may be displaced relative to one another, for example by moving the holding apparatus along the electrode, that is to say parallel to the electrode longitudinal axis, or by lifting the supporting apparatus. The electrode may then be resecured, for example clamped, with the aid of the gripping unit.

LIST OF REFERENCES

[0078] 1 system [0079] 2 electrode [0080] 2a upper electrode end [0081] 3 electric arc furnace [0082] 4 holding apparatus [0083] 4a lifting unit [0084] 4b carrying arm [0085] 4c gripping unit [0086] 5 sensor apparatus [0087] 6 processing apparatus [0088] 7 control apparatus [0089] 8 vessel [0090] 9 supporting apparatus [0091] 10 sensor lifting apparatus [0092] 11 laser sensor [0093] 12 laser beam [0094] 13 working means [0095] H1, H2 first, second holding position [0096] D1 horizontal distance [0097] D2 first distance [0098] E1, E2 electrode segment [0099] A distance profile [0100] z displacement path [0101] L electrode longitudinal axis [0102] P arrow [0103] V connecting position [0104] B connecting region [0105] 100 method [0106] S1-S4 method steps