STRAND GUIDING SYSTEM AND METHOD FOR THE CONFIGURATION OF SUCH A STRAND GUIDING SYSTEM

Abstract

A method and a system for configuring a strand guiding system (8, 8a, 8b) of a continuous casting machine (2) and such a strand guiding system (8, 8a, 8b). A strand guiding segment (10g-r) guides a metal strand in the strand guiding system (8, 8a, 8b). The strand guiding system (8, 8a, 8b) has a plurality of strand guiding segments (10g-r) and respective control units (22g-r), wherein each control unit (22g-r) identifies its strand guiding segment (10g-r), and each control unit (22g-r) automatically depends on the strand guiding segments (10g-r) identified by the control unit (22g-r). The strand guiding system (8, 8a, 8b) and the strand guiding segment (10g-r) are prepared for the performance of the method herein disclosed.

Claims

1. A method for configuring a strand guiding system of a continuous casting machine, wherein the strand guiding system has a plurality of strand guiding segments and a plurality of control units, and respectively one control unit is assigned to each strand guiding segment, the method comprising: causing each control unit to identify the respective strand guiding segment assigned thereto by using a segment-specific item of information, which is software and/or hardware coded; and configuring each control unit substantially automatically in dependence on the strand guiding segment identified by it, by at least one of setting operating parameters and by selection of a computer-readable program code.

2. The method as claimed in claim 1, wherein the software coding comprises a data item, the method further comprising storing the data item in a storage unit of the strand guiding segment.

3. The method as claimed in claim 1, wherein the hardware coding comprises a strand segment-specific plug connection of the strand guiding segment.

4. The method as claimed in claim 1, wherein the control units are at least one of logically and physically separate, and at least some of the control units that are substantially the same are assigned to strand guiding segments of differing structural types or they are not so assigned.

5. The method as claimed in claim 1, further comprising assigning a main control unit to the control units substantially automatically in dependence on the identified strand guiding segments by at least one of setting of operating parameters and by selection of a computer-readable program code.

6. The method as claimed in claim 1, further comprising configuring the strand guiding system after at least one of demounting and mounting of a strand guiding segment from or into the strand guiding system.

7. A strand guiding system comprising: a plurality of strand guiding segments each configured for guiding a respective metallic strand, each strand guiding segment has at least one of a software coding and a hardware coding for identification thereof, and a plurality of control units, wherein one of the control units is respectively assigned to each strand guiding segment and is configured for the purpose of controlling the strand guiding segment by means of an open-loop or a closed-loop control signal; the control units are configured for identification of the strand guiding segment respectively assigned thereto by use of at least one of the software coding and the hardware coding of the respective strand guiding segment; and each control unit has a configuration that is configured to be adapted substantially automatically, in dependence on the identified strand guiding segment, by at least one of setting of operating parameters and by selection of a computer-readable program code.

8. The strand guiding system as claimed in claim 7, further comprising each strand guiding segment has a storage unit comprising at least one of an RFID storage element and a RAM storage module, on which the software coding can be stored.

9. The strand guiding system as claimed in claim 7, further comprising the hardware coding comprises a mechanical element of a segment-specific plug connection.

10. The strand guiding system as claimed in claim 7, further comprising each control unit has a plurality of closed-loop control elements, wherein each closed-loop control element is respectively assigned to a strand guiding roller of the strand guiding segment assigned to the respective control unit, wherein the strand guiding roller can be set individually against the strand.

11. The strand guiding system as claimed in claim 7, further comprising a main control unit, which is assigned to the control units and which is prepared to control the control units by means of a respective setpoint value signal for forming open-loop or closed-loop control signals, and which is connected to the control units via a network connection.

12. The strand guiding system as claimed in claim 11, further comprising: the main control unit is configured to identify the strand guiding segments indirectly assigned thereto; and has a configuration that can be adapted substantially automatically, in dependence on the identified strand guiding segments, by at least one of setting of operating parameters and by selection of a computer-readable program code.

13. The strand guiding system of claim 1, further comprising a plurality of the control units which are substantially the same are assigned to strand guiding segments of differing structural types.

14. The method as claimed in claim 5, further comprising: basing the strand guiding system on an open-loop control or a closed-loop control of the strand guiding system by determining open-loop or closed-loop control signals of the strand guiding system depending upon the identified strand guiding segments; determining setpoint values for the open-loop control or the closed-loop control of at least one of setting positions of the strand guiding rollers and setting forces of the settable strand guide rollers; determining the setting forces or the setting positions of the strand guide rollers by use of a simulation model comprised of a computer-readable program code on a processor unit of the main control unit; and using the respective determined setpoint value to determine a manipulated value for at least one of the setting positions and the setting forces and using the determined manipulated value by means of the open-loop or closed-loop control signals for influencing at least one of the setting positions and the setting forces of the settable strand guiding rollers.

15. The method as claimed in claim 14, wherein one of the closed-loop control elements is assigned to a strand guiding roller of a strand guiding segment assigned to one of the control units.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] FIG. 1 is a schematic representation of a continuous casting machine, with a strand guiding system that has a plurality of strand guiding segments,

[0073] FIG. 2 is a schematic illustration of a portion of the strand guiding system from FIG. 1, with control units and a main control unit,

[0074] FIG. 3 is a schematic illustration of a further strand guiding system, with strand guiding segments that have variously coded segment-specific items of information,

[0075] FIG. 4 is a schematic illustration of a further strand guiding system, with control units that each has a plurality of closed-loop control elements,

[0076] FIG. 5 shows a schematic representation of a hydraulic means for supplying power fluid to a strand guiding segment from FIG. 4, and

[0077] FIG. 6 shows a detailed schematic representation of a hydraulic unit from FIG. 5.

DESCRIPTION OF EMBODIMENTS

[0078] Features that are the same, but that may have slight differences, for example in an amount or a number value, in a dimension, a position and/or a function or the like, are denoted by the same reference numeral and a reference letter, or a different reference letter. If only the reference numeral is mentioned, without a reference letter, this relates to all the corresponding components of all exemplary embodiments.

[0079] FIG. 1 shows a schematic representation of a continuous casting machine 2 for producing a metallic strand. The continuous casting machine 2 has a ladle turret 4, a mold 6, and a strand guiding system 8 having a plurality of strand guiding segments 10a to 10l.

[0080] The continuous casting machine 2 is located in a hall, which is supported, with respect to a foundation, by means of a hall framework having a plurality of steel girders 12. The continuous casting machine 2 is supported on a supporting structure 14.

[0081] For the purpose of producing a metallic strand, liquid steel is supplied to the mold 6 via the ladle turret 4. In the mold 6, the liquid steel is brought to solidification, at least in a lateral edge zone, supplied continuously and already in the form of a partly solidified strand, from the mold 6 to the strand guiding system 8 of the continuous casting machine 2, and is conveyed through the latter.

[0082] The strand is guided, supported and subjected to further cooling by the strand guiding system 8. For this purpose, the strand guiding system 8 has a plurality of strand guiding segments 10a to 10l.

[0083] FIG. 2 shows a schematic illustration of a portion of the strand guiding system 8 from FIG. 1, with only the strand guiding segments 10g to 10l being represented in FIG. 2.

[0084] The strand guiding segments 10g, 10h and 10i are realized as so-called 4-axis segments, having strand guiding rollers 16 that can each be set against the strand in multiples. The strand guiding segments 10j, 10k and 10l are realized in a cassette design, having strand guiding rollers 18 that can each be set singly against the strand. Each of the strand guiding segments 10j to 10l respectively has a plurality of roller units 20, more precisely seven, which are structurally substantially the same and which are disposed in succession, in the manner of a cassette, in a strand longitudinal direction L.

[0085] Assigned to each of the strand guiding segments 10g to 10l respectively is a control unit 22g to 221 for controlling the respective strand guiding segment 10g to 10l by means of a respective open-loop or closed-loop control signal 24g to 24l, or open-loop or closed-loop control signals 24g to 24l.

[0086] The control units 22 are connected to the strand guiding segment 10g to 10l assigned thereto via a field bus 26, and are realized substantially with identical hardware, i.e. are structurally the same.

[0087] The control units 22 are prepared to identify the strand guiding segment 10 respectively assigned thereto by use of a segment-specific coding, here, specifically, a coding that indicates the structural type of the respective strand guiding segment 10. In addition, the control units 22 each have a configuration 28 that can be adapted substantially automatically to strand guiding segments of differing types, more precisely to differing structural types of strand guiding segment, for example to the open-loop or closed-loop control specifications of 4-axis segments and/or cassette-type segments.

[0088] In the present case, the control units 22g to 221 respectively have a configuration 28g to 28l that is adapted substantially automatically in dependence on the respectively identified strand guiding segment 10g to 10l.

[0089] The configurations 28g to 28l in the present exemplary embodiment are to be understood to be, respectively, specifically set operating parameters of the control units 22g to 221, and specific computer-readable programs, or software, that are executed on the control units.

[0090] The configurations 28g, 28h and 28i of the control units 22g, 22h and 22i, respectively, are adapted to the segment structural type, i.e. to the structural type, or to the type of control that is required by the structural type of the strand guiding segments 10g, 10h and 10i. The configurations 28j, 28k and 28l of the control units 22j, 22k and 22l, respectively, on the other hand, are adapted to the segment type, i.e. the structural type, of the strand guiding segments 10j, 10k and 10l, and differ from the configurations 28g to 28i.

[0091] Such an assignment of control units 22 that are substantially the same i.e. control units of the same structural type, having configurations 28 that can be adapted in dependence on the respectively identified strand guiding segment 10 makes it possible, in particular, to achieve a high proportion of component homogeneity within the strand guiding system 8.

[0092] The control units 22 are connected to a main control unit 32 via a network connection 30. The main control unit 32 is assigned to the control units 22, and is prepared to control the latter by means of a respective setpoint value signal 34g to 341 for forming open-loop or closed-loop control signals 24. In addition, the main control unit 32 has a configuration 36. The main control unit 32 is prepared to identify the strand guiding segments 10 indirectly assigned thereto. The configuration 36 can be adapted substantially automatically in dependence on the identified strand guiding segments 10.

[0093] For the purpose of configuring the strand guiding system 8, each control unit 22 identifies the strand guiding segment 10 respectively assigned thereto, and each control unit 22 is configured substantially automatically in dependence on the strand guiding segment 22 identified by it. This means that the respective operating parameters and software settings of the control units 22 are adapted in such a manner, in dependence on the respectively identified strand guiding segment 10, that the respective strand guiding segment 10 can be controlled in a manner appropriate to the structural type.

[0094] In the present exemplary embodiment, the identification is effected by means of respectively one segment-specific item of information that is transmitted, via the field bus 26, from each strand guiding segment 10 to the control unit 22 respectively assigned thereto. These items of information are transmitted to the main control unit 22 via the network connection 30. The configuration 36 of the main control unit is adapted substantially automatically in dependence on these items of information, or in dependence on the identified strand guiding segments 10. Alternatively, the configuration of the main control unit 32 may also be adapted to the configurations 28g to 28l of the control units 22g to 221 in this way, the control units 22 can be controlled by means of signals and/or supplied with data in a required manner which may correspond to an indirect adaptation of the configuration 36 to the identified strand guiding segments 10.

[0095] The descriptions of exemplary embodiments that follow are generally limited substantially to the differences in relation to the exemplary embodiments from FIG. 1 and FIG. 2, to which reference is made with respect to features and functions that remain the same. Components that remain substantially the same are basically denoted by the same references, and features that are not mentioned are included in the following exemplary embodiments without being described over again.

[0096] FIG. 3 shows a schematic illustration of a further strand guiding system 8a, having strand guiding segments 10m to 10p, control units 22m to 22p, and a main control unit 32a. Via a field bus 26a, the strand guiding segments 10m to 10p are connected, by information or data connection means, to the control units 22m to 22p assigned thereto. The control units 22m to 22p are connected to the main control unit 32a via a network connection 30a.

[0097] The strand guiding segments 10m to 10p each have a segment-specific item of information 38m to 38p for identification thereof by the control unit 22 assigned thereto, or by the main control unit 32a. The segment-specific items of information 38 are coded, at least partly, in differing ways.

[0098] The strand guiding segments 10m and 10o each have a hardware coding 40, and the strand guiding segments 10n and 10p each have a software coding 42.

[0099] The hardware codings 40 are each constituted by segment-specific plug connections 44m and 44o, respectively. The segment-specific plug connections 44m and 44o are plug connections for connecting the strand guiding segments 10m and 10o, respectively, to the field bus 26a. The plug connections 44m and 44o are segment-specific in the sense that they are assigned to the respectively specific structural type of the strand guiding segment 10m and 10o, respectively. In the present exemplary embodiment, the segment-specific plug connection 44m is a 4-pole plug connection, the plug connection 44o being a 6-pole plug connection.

[0100] The software codings 42 are each constituted by a data item 46n and 46p, respectively, in a storage unit 48n and 48p, respectively, of the strand guiding segment 10n and 10p, respectively.

[0101] The storage unit 48n is a RAM storage module 50, from which the segment-specific items of information 38n, or the segment-specific data item 46n, can be read out and transmitted, via the field bus 26a, to the control unit 22n.

[0102] The storage unit 48p is an RFID storage element 52, from which the segment-specific item of information 38p can be read out contactlessly by use of a read unit 54 and transmitted, via the field bus 26a, to the control unit 22p.

[0103] The configuring of the strand guiding system 8a is effected in dependence on the segment-specific items of information 38m to 38p as follows:

[0104] The strand guiding segment 10m has been or is connected, by means of the segment-specific plug connection 44m, via the field bus 26a, to the control unit 22m assigned thereto. The control unit 22m identifies the structural type of the strand guiding segment 10m on the basis of the segment-specific plug connection 44m used, and is configured, in dependence on the strand guiding segment 10m, or the structural type thereof, in such a manner that a configuration 28m adapted to the structural type of the strand guiding segment 10m is loaded, or established.

[0105] In addition, the strand guiding segment 10o has been or is connected, by means of the segment specific plug connection 44o which differs structurally from the plug connection 44m to the control unit 22o assigned thereto, via the field bus 26a. The control unit 22o identifies the structural type of the strand guiding segment 10o which differs from that of the strand guiding segment 10m on the basis of the segment-specific plug connection 44o used, and is configured, in dependence on the strand guiding segment 10o, or the structural type thereof, in such a manner that a configuration 28o adapted to the structural type of the strand guiding segment 10m is loaded, or established.

[0106] Furthermore, the segment-specific data item 46n is read out from the storage unit 48n, i.e. the RAM storage module 50, of the strand guiding segment 10n, and transmitted to the control unit 22n via the field bus 26a. The control unit 22n identifies the strand guiding segment 10n, or the structural type thereof, by use of the data item 46n, and is configured, in dependence on the strand guiding segment 10n, or the structural type thereof, in such a manner that a configuration 28n adapted to the structural type of the strand guiding segment 10n is loaded, or established.

[0107] Further, the segment-specific data item 46p is read out of the storage unit 48p, i.e. the RFID storage element 52, of the strand guiding segment 10p by use of the read unit 54, and transmitted to the control unit 22p via the field bus 26a. The control unit 22p identifies the strand guiding segment 10p, or the structural type thereof, by use of the data item 46p, and is configured, in dependence on the strand guiding segment 10p, or the structural type thereof, in such a manner that a configuration 28p adapted to the structural type of the strand guiding segment 10n is loaded, or established.

[0108] The segment-specific items of information 38m to 38p are transmitted to the main control unit 32a. The main control unit 32a has an operator interface 56, which has a configuration 58 in the form of a graphical user interface for illustrating operating data of the strand guiding system 8a and of the mounted strand guiding segment 10 that is prepared for adaptation to strand guiding segments of differing types and, by use of the segment-specific items of information 38m to 38p, is adapted to the strand guiding segments 10m to 10p.

[0109] In addition, a computer-assisted simulation model 60, on which the open-loop control or closed-loop control of the strand guiding system 8a is based, is executed on the main control unit 32a, or on a processor unit of the main control unit 32a that is not represented for reasons of simplicity, in particular for the purpose of calculating setpoint values for setting positions and/or setting forces of the strand guiding rollers 16, 20 (see FIG. 1). The simulation model has a configuration 62 in the form of model variables and/or simulation parameters which is prepared for adaptation to strand guiding segments of differing types and, by use of the segment-specific items of information 38m to 38p, is adapted to the strand guiding segments 10m to 10p.

[0110] FIG. 4 shows a schematic illustration of a further strand guiding system 8b, having control units 22q and 22r, which are assigned to the strand guiding segment 10q and the strand guiding segment 10r, respectively, and which each have a plurality of closed-loop control elements 64.

[0111] Each of the closed-loop control elements 64a to 64g is assigned, respectively, to at least one strand guiding roller 16 or 18 of the strand guiding segment 10q or 10r that is assigned to the respective control unit 22q or 22r, respectively, which strand guiding roller can be set against the strand.

[0112] In the present exemplary embodiment, the closed-loop control elements 64 are realized in software and in the present case are each a constituent part of the configurations 28q or 28r, respectively, of the control means 22q and 22r.

[0113] The closed-loop control elements 64 are prepared, by use of a known closed-loop control law, a setpoint value and an actual value of a controlled variable, to determine a manipulated value, or a closed-loop control signal, for influencing the controlled variable. Here, the controlled variable is, respectively, a setting position and/or a setting force of one or more of the settable strand guiding rollers 16 or 18 of the strand guiding segments 10q and 10r.

[0114] Each of the closed-loop control elements 64a to 64e of the control unit 22r is assigned to at least one of the roller units 20 (see also FIG. 1) of the strand guiding segment 10r and consequently at least to one of the individually settable strand guiding rollers 18.

[0115] More precisely, the closed-loop control element 64a is assigned to the roller unit 20a, the closed-loop control element 64b is assigned to the roller unit 20b, the closed-loop control element 64c is assigned to the roller unit 20c, the closed-loop control element 64d is assigned to the roller unit 20d, and the closed-loop control element 64e is assigned to the roller unit 20e, such that respectively one closed-loop control element is assigned to precisely one roller unit. In addition, the closed-loop control element 64e is assigned to the roller unit 20f and to the roller unit 20g i.e. to two of the roller units 20.

[0116] The roller units 20a to 20g are each′constituted by a strand guiding roller 18 that can be set individually against the strand, and an adjustment means for setting this strand guiding roller. The roller units 20a to 20g are prepared for individual demounting from and/or mounting into the strand guiding segment 10r, and connected individually to the control unit 22r assigned to the strand guiding segment 10r, the connection in the present case being established via an aggregate cable 68 composed of a plurality of connecting cables.

[0117] The closed-loop control element 64f is assigned to a roller means 66a, and the closed-loop control element 64g is assigned to a roller means 66b, of the strand guiding segment 10q. The roller means 66a and 66b are each constituted by an adjustment means and by strand guiding rollers that can be set in multiples against the strand.

[0118] For the purpose of configuring the strand guiding system 8b, each of the control units 22q and 22r identifies the strand guiding segment 10q or 10r respectively assigned thereto, by use of the segment-specific item of information 38q or 38r, respectively (see FIG. 2). The control units 22q and 22r are each configured substantially automatically in such a manner that a necessary number of the software-based closed-loop control elements 64 is determined, according to the structural type of the identified strand guiding segment 10q or 10r, and the closed-loop control elements are assigned appropriately according to the structural type.

[0119] FIG. 5 shows a schematic representation of a hydraulic means 100 for supplying power fluid to the strand guiding segment 10r from FIG. 4, the hydraulic means 100 being prepared to supply the individual roller units 20a to 20g of the strand guiding segment 10r.

[0120] The hydraulic means 100 has a first infeed means 102, which is assigned to the roller units 20a to 20f and indirectly connected to the latter, and a second infeed means 104, which is assigned to the roller unit 20g and indirectly connected to the latter.

[0121] In addition, the hydraulic means 100 has a first power fluid infeed line 106, which is connected to the first infeed means 102, and a second power fluid infeed line 108, which is connected to the second infeed means 104, and a power fluid discharge line 110.

[0122] The first infeed means 102 starting from the first power fluid infeed line 106 has a shut-off valve 112a, an electromagnetically controllable 3/2-way valve 114a, a hose rupture safety means 116a, a pressure gauge 118a and a non-return valve 120a, and is connected to a power fluid line 122a that is common to the roller units 20a to 20f.

[0123] The second infeed means 104 starting from the second power fluid infeed line 108 has a shut-off valve 112b, an electromagnetically controllable 3/2-way valve 114b, a hose rupture safety means 116b, a pressure gauge 118b and a non-return valve 120b, and is connected to a power fluid line 122b that is common to the roller unit 20g.

[0124] The power fluid lines 122a and 122b each have a pressure measuring means 124a and 124b, respectively.

[0125] The power fluid discharge line 110 is connected to a tank discharge line 126 that is common to the roller units 20a to 20g, and has a throttle valve 128 and a non-return valve 120c.

[0126] The individually settable strand guiding rollers 18a to 18g of the roller units 20a to 20g can each be set by means of two double-acting hydraulic cylinders 130aa and 130ab to 130ga and 130gb, and are each respectively supplied with power fluid and controlled via a hydraulic unit 132a to 132g.

[0127] The hydraulic units 132a to 132f are connected to the power fluid line 122a, and the hydraulic unit 132g is connected to the power fluid line 122b, all hydraulic units 132a to 132g being connected to the common tank line 126.

[0128] FIG. 6 shows a detailed schematic representation of the hydraulic unit 132a. FIG. 6 shows how the hydraulic cylinders 130aa and 130ab of the individually settable strand guiding roller 18a can be controlled by means of the hydraulic unit 132a, in particular in combination with the control unit 22r (see FIG. 4).

[0129] The hydraulic unit 132a is realized as a constituent part of the roller unit 20a and is mounted, for example, directly on the roller unit 20a, or on a frame thereof.

[0130] The hydraulic unit 132a has a first infeed unit 134, which is connected to the hydraulic cylinder 130aa for the purpose of driving the latter, and a second infeed unit 136, which is connected to the hydraulic cylinder 130ab for the purpose of driving the latter.

[0131] The infeed units 132 and 134 are connected indirectly to the power fluid line 122a for the purpose of supplying it with power fluid, via the hydraulic means 100 (see FIG. 5), and connected directly to the tank line 126, for the purpose of discharging power fluid.

[0132] A pressure regulating unit 138 is connected upstream from the infeed units 132 and 134, in the direction of the power fluid line 122a.

[0133] The pressure regulating unit 138 is connected directly to the power fluid line 122a, and has a pressure regulating valve 140, a 3/2-way valve 114c and a pressure measuring means 124c.

[0134] The infeed unit 132 has a 4/3-way valve 142a that has a floating mid-travel position. In the infeed direction, leading to the hydraulic cylinder 130aa, the infeed unit 132 has a shuttle valve 144a downstream from the 4/3-way valve 142a, two controllable non-return valves 146a and 146b, two diaphragm valves 148a and 148b, a settable pressure limiting valve 150a, two pressure measuring means 124d and 124e, a pressure limiting valve 152a and a non-return diaphragm valve 154a.

[0135] The infeed unit 134 has a 4/3-way valve 142b that has a floating mid-travel position. In the infeed direction, leading to the hydraulic cylinder 130ab, the infeed unit 134 has a shuttle valve 144b downstream from the 4/3-way valve 142b, two controllable non-return valves 146c and 146d, two diaphragm valves 148c and 148d, a settable pressure limiting valve 150b, two pressure measuring means 124f and 124g, a pressure limiting valve 152b and a non-return diaphragm valve 154b.

[0136] In addition, the roller unit 20a has two displacement measuring means 156a and 156b, which are each respectively assigned to one of the hydraulic cylinders 130aa and 130ab, and which are prepared to determine a setting position of the settable strand guiding roller 18a.

[0137] A closed-loop control of the setting position of the strand guiding roller 18a is effected, in particular, by use of the 4/3-way valves 142a and 142b assigned to the hydraulic cylinders 130aa and 130ab, and of the displacement measuring means 156a and 156b. By appropriate controlling of the 4/3-way valves 142a and 142b by the control unit 22r (see FIG. 4) by means of a control signal, the 4/3-way valves 142a and 142b are moved out of a mid-travel position, and a roller gap between the strand and the strand guiding roller 18a is opened or closed.

[0138] In particular, the 4/3-way valves 142a and 142b are controlled by the closed-loop control element 64a (see FIG. 4), which is assigned to the roller unit 20a, and which may be a 3-point controller or a higher-order controller, and the strand guiding roller 18a is thereby adjusted to a setpoint setting position or a setpoint setting force. The positioning closed-loop control may be effected independently of a setting force of the strand guiding roller 18a. A minimum and/or a maximum setting force may be ensured by the hydraulic unit 132a, the hydraulic means 100 and/or by a corresponding configuration of the control unit 22r.

[0139] Further, a setting force of the strand guiding roller 18a may be determined, by the determination of a respective pressure in the respectively two chambers of the hydraulic cylinders 130aa and 130ab, by means of the pressure measuring means 124d and 124e, and 124f and 124g, respectively.

[0140] The mid-travel position of the 4/3-way valves 142a and 142b is held by means of the non-return valves 146a to 146d. A travel speed of the strand guiding roller 18a, or of the hydraulic cylinders 130aa and 130ab, is limited by the diaphragm valves 148a to 148d.

[0141] A closed-loop control of a setting force of the strand guiding roller 18a is effected, in particular, by use of the pressure regulating valve 140 upstream from the 4/3-way valves 142a and 142b and the pressure measuring means 124c, the controllable non-return valves 146a to 146d also: holding valves being gradually opened via the shuttle valves 144a and 144b, respectively. The closed-loop control of the setting force may be effected independently of the setting position of the strand guiding roller 18a. Further, a minimum and/or a maximum setting position of the strand guiding roller 18a are/is ensured, thereby avoiding inadmissible variances between the hydraulic cylinders 130aa and 130ab and/or the roller units 20a to 20g of the strand guiding segment 10r.

[0142] Further, a closed-loop control of the setting position of the strand guiding roller 18a may be effected indirectly, or implicitly, by a closed-loop control of the setting force of the strand guiding roller 18a. In this case, the setting force is increased or reduced in dependence on a deviation from a setpoint value of the setting position that can be determined by means of the displacement measuring means 156a and 156b. This dependence, and consequently a rigidity, may be freely selectable within fixed limits, in particular by means of a corresponding configuration of the control unit 22r.

[0143] In addition, the setting force of the strand guiding roller 18a may be controlled indirectly, or implicitly, by means of a closed-loop control of the setting position, in which the setting position is controlled by closed-loop control in such a manner that an average setting force corresponds substantially to a predefined setpoint value of the setting force.

[0144] Preferably, the setting forces of the individually settable strand guiding rollers 18 of the roller units 20 are controlled by closed-loop control in a completely solidified region of the strand, i.e., for example, in the region of the strand guiding segments 10j to 10l of the strand guiding system 8 (see FIG. 1).

[0145] In addition, it is advantageous if the setting positions of the strand guiding rollers 16 or 18 of the strand guiding segments, or of the roller units, are controlled by closed-loop control in a partly solidified region of the strand, i.e., for example, in the region of the strand guiding segment 10a to 10i of the strand guiding system 8 (see FIG. 1).

[0146] In the case of a signal failure, for example resulting from a malfunction of the control unit 22r, the pressure regulating valve 140 establishes a balance between an outlet pressure and a supply pressure of a power fluid. In the case of a malfunction of the displacement measuring means 156a or 156b, the hydraulic cylinders 130aa and 130ab can be held in a position by a gradual shutting-off of the 4/3-way valves 142a and 142b, respectively, via the non-return valves 146a to 146d. In the event of a malfunction, for example, of the 4/3-way valves 142a and/or 142b, the strand guiding roller 18a can be held in a position by a gradual shutting-off of the 3/2-way valves 114c, via the non-return valves 146a to 146d.

LIST OF REFERENCES

[0147] 2 continuous casting machine [0148] 4 ladle turret [0149] 6 mould [0150] 8, 8a, 8b strand guiding system [0151] 10a-10r strand guiding segment [0152] 12 steel girder [0153] 14 supporting structure [0154] 16 strand guiding rollers [0155] 18, 18a-18g individually settable strand guiding rollers [0156] 20, 20a-20g roller unit [0157] 22g-22r control unit [0158] 24g-24l open-loop control signal, closed-loop control signal [0159] 26, 26a field bus [0160] 28g-28p configuration [0161] 30 network connection [0162] 32, 32a, 32b main control unit [0163] 34g-341 setpoint value signal [0164] 36, 36b configuration [0165] 38m-38r segment-specific item of information [0166] 40 hardware coding [0167] 42 software coding [0168] 44m, 44o segment-specific plug connection [0169] 46n, 46p segment-specific data item [0170] 48n, 48p storage unit [0171] 50 RAM storage module [0172] 52 RFID storage element [0173] 54 read unit [0174] 56 operator interface [0175] 58 configuration [0176] 60 simulation model [0177] 62 configuration [0178] 64a-64g closed-loop control element [0179] 66, 66b roller means [0180] 68 aggregate cable [0181] 100 hydraulic means [0182] 102 infeed means [0183] 104 infeed means [0184] 106 power fluid infeed line [0185] 108 power fluid infeed line [0186] 110 power fluid discharge line [0187] 112a, 112b shut-off valve [0188] 114a-114c 3/2-way valve [0189] 116a, 116b hose rupture safety means [0190] 118a, 118b pressure gauge [0191] 120a-120c non-return valve [0192] 122a, 122b pressure fluid line [0193] 124a-124g pressure measuring means [0194] 126 tank line [0195] 128 throttle valve [0196] 130aa-130gb hydraulic cylinder [0197] 132a-132g hydraulic unit [0198] 134 infeed unit [0199] 136 infeed unit [0200] 138 pressure regulating unit [0201] 140 pressure regulating valve [0202] 142a, 142b 4/3-way valve [0203] 144a, 144b shuttle valve [0204] 146a-146d controllable non-return valve [0205] 148a-148d diaphragm valve [0206] 150a, 150b settable pressure limiting valve [0207] 152a, 152b pressure limiting valve [0208] 154a, 154b non-return diaphragm valve [0209] 156a, 156b displacement measuring means [0210] L strand longitudinal direction