Patent Publication Number: US-2018043426-A1

Title: Roller device

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part application of application Ser. No. 13/698,740 filed Feb. 25, 2013 which is a National Stage application of International application PCT/EP2011/057570 filed May 11, 2011 and claiming priority of German applications DE 10 2010 020937.6 filed May 19, 2010 and DE 10 2011 003194.4 filed Jan. 26, 2011, all of the above-mentioned applications are incorporated herein by reference thereto. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a roller device having at least one roller arranged on a cross-beam extending in a direction of the roller axis. Several such roller devices can be assembled in strand guides of casters, in particular, in complete casting bows, or separate roller aprons, or be formed as drive rollers, transportation rollers, or straightening rollers. 
     2. Description of the Prior Art 
     Roller devices with roller elements supported on cross-beams are known. 
     DE 26 37 179 discloses a strand guide for a continuous casting installation in which bearing housings that support respective rollers, are cooled, respectively, by cooling medium fed by separate tubular conduit. 
     JP 08 168 859 A discloses a device for cooling roller segments in a continuous casting installation wherein the bearing housings of respective roller segments are supplied with cooling medium by separate tubular conduits. 
     EP 1 355 752 B1 discloses a strand guide segment that includes, in addition to a plurality of rollers, cross-beam elements which are used for a secondary cooling of a slab. 
     The drawback of the known solutions in which separate tubular conduits are used for feeding cooling medium, consists in that the tubular conduits are particularly susceptible to damages due to a high heat load and the danger of breakthroughs. 
     When separate segments need be repaired or a cyclical replacement of respective roller devices take place, these roller devices should be connected with respective, to-be-separately mounted, tubular conduit systems, as a result of which repair and maintenance costs as well as breakdown of the installation are at a significantly higher level. 
     SUMMARY OF THE INVENTION 
     Proceeding from the known state of the art, the object of the present invention is to increase the availability of the installation and the reliability of the roller devices or segments in a caster. 
     This object is achieved by a roller device with features of claim  1 . 
     Correspondingly, there is provided a roller device including a cross-beam and at least one roller element supported on the cross-beam by roller bearings. According to the present disclosure conduit means for at least three different media is provided in the cross-beam. The conduit means is particularly provided for conducting cooling medium for cooling the roller bearings, cooling medium for inner cooling of the roller, and lubricant medium for lubrication of the roller bearings. 
     Under the term “medium”, in the present disclosure, in addition to different cooling media and lubrication media which should be fed to a roller device and partially discharged therefrom, also power supplies for sensors and switching devices as well as for data bases are understood. In other words, under the term “medium” in the present disclosure, different operational means and control means, which are fed to the roller device during operation and are discharged therefrom, are understood. 
     Advantageously, with formation of a such roller unit with a such cross-beam, in which at least three different media can be fed thereto by conduit elements, i.e., for example, cooling medium for cooling the bearing, cooling medium for inner cooling of the roller, lubricant medium, cooling medium for secondary cooling, hydraulic medium for a hydraulic control circuit, compressed air medium for a pneumatic control circuit, power supply, signal transmission of a sensor, etc., the respective conduit elements are very much protected within the cross-beam and provide, correspondingly, in comparison with laying of separate tubular conduits on the outer side, a higher reliability and availability of the installation. Furthermore, during repair works, additional operational processes for connecting separate tubular conduits, e.g., for feeding or discharge of cooling medium, to each bearing are eliminated. 
     As a cooling medium for cooling of the bearing, inner cooling of the roller, and/or secondary cooling, a one-component cooling material, e.g., water, or a two-component cooling material, e.g., a water/air mixture can be used. Naturally, other material mixtures or multi-material mixtures can be used. 
     Advantageously, a conduit element is provided, respectively, for conducting at least one of the following media: cooling medium for cooling the roller bearing, cooling medium for inner cooling of the roller, lubricant medium for lubrication of the roller bearing, cooling medium for secondary cooling (e.g., one-component or two component cooling), hydraulic medium for a hydraulic control circuit, compressed air medium for a pneumatic control circuit, power medium for an electrical power supply, power medium for electrical control signals, power medium for electrical measurement signals, power medium for optical measurement signals or electrical and/or optical bus system. In this way, a corresponding simplification of feeding of respective media can be achieved. 
     According to a further advantageous embodiment, there is provided a roller device, in particular, for forming strand-guiding segments of a caster and including a cross-beam and at least one roller element supported on the cross-beam by roller bearings, wherein at least one a conduit element is provided, in the cross-beam for conducting at least one of the following media: cooling medium for inner cooling of the roller, cooling medium for secondary cooling (e.g., one-component or two component cooling), hydraulic medium for a hydraulic control circuit, compressed air medium for a pneumatic control circuit, power medium for an electrical power supply, power medium for electrical control signals, power medium for electrical measurement signals, power medium for optical measurement signals or electrical and/or optical bus system. Conducting these new “media” directly in the cross-beam opens new possibilities with regard to assembly and reliability of the roller elements. 
     In a further advantageous embodiment, the roller device includes a cross-beam and at least one roller element supported on the cross-beam by roller bearings, wherein at least one conduit element for conducting at least one medium is provided in the cross-beam, and the roller device is provided for forming a strand-guiding segment of a caster. 
     Up to the present, roller cross-beams (cross-beam with a roller mounted thereon) were used only in casting bows but not in segments. In the casting bow, the rollers with the cross-beam should be dismounted separately and, thus, dismounting always leads to a longer shut down and loss of production. Because the support beams for supporting the rollers are arranged in a casting bow in the casting direction, the roller cross-beams have a comparatively large resistance torque (large height) for supporting the roller, noticeably larger than the resistance torque of media cross-beams mounted in segments. 
     Up to the present, the media cross-beams with a mounted roller are fitted only in casting bows but not in segments of continuous casting installations. Here, for a more clear distinction, the following definitions are provided: 
     Transverse installation: All of the roller pairs of a strand guide up to the maximum position in which the strand should be completely solidified, are arranged beneath each other transverse to each other. 
     (Circular) bow installation: the copper plates of molds and a larger part of roller pairs are geometrically arranged in a circular arc, with the circular arc defining an angle of about 90°. In the casting direction, straightening roller pairs, which straighten the cast strand and guide it onto a horizontal portion of the strand guide, adjoin the circular arc. 
     Transverse bending installation: combination of both above-described types according to which the mold plates and the first roller pairs are arranged transverse beneath each other, with the strand being subsequently bent in a circular arc by the roller pairs. Straightening roller pairs, which straighten the cast strand and guide it onto a horizontal portion of the strand guide, again adjoin the circular arc. 
     Casting bow (strand guide): The casting bow is an old state-of-the-art that, e.g., was (is) used in transverse bending installations, wherein a portion of a strand guide, which completely lies in the circular arc, forms, with regard to machine construction, an integral part of the casting bow, i.e., the number of roller pairs typically amounts, in order of magnitude, to 25-45 roller pairs; the support cross-beams, which are arranged in the casting direction, provide support for casting bow for rollers with roller cross-beams; when roller cross-beams are used, they are formed, for supporting the rollers, with a comparatively big resistance torque (big value, e.g., at Arcelo Metal Steel, with thickness 100 mm) (a very robust construction). 
     Segment (strand guide): a new form of strand guides: the number of roller pairs, maximum 10 in the bow section and maximum 14-16 in the transverse section or bending section of the strand guide (in particular at small roller diameters); in the bow section, there are always more segments; in the segment, the support cross-beams for rollers are located beneath the roller bodies, i.e. the support cross-beams are arranged transverse to the casting direction. The tubular conduits for a roller extend along the support cross-beams are arranged transverse to the casting direction. The tubular conduits for a roller extend along the support beams; the rollers are not exchanged in the installation, but rather in the segment shop; at that, a complete segment is replaced. The upper frame and the lower frame of a segment form a unit, the dismounting of segments from a strand guide always takes place upwards. 
     Bow segment (strand guide): As a segment with maximum 10 roller pairs, wherein the roller pairs geometrically are arranged on a circular arc section. 
     Advantageously, the conduit elements for the media are provided in form of bores, in particular, deep hole bores in the cross-beam, in form of channels in the cross-beam covered by a roof, and/or in form of tubular conduits arranged within the cross-beam. 
     In this way, the roller device can be formed as a complete module, and the corresponding conduit elements provided in the cross-beam for different media can be completely tested and adjusted in the pre-assembled module. In this way, a segment can be repaired in a shorter time and with less expenses. E.g., a somewhat damaged roller device within a segment including 14 roller devices, can be easily replaced. Because the roller device is pre-assembled, pre-tested and pre-adjusted, the exchange in the segment can proceed rapidly. Correspondingly, repair expanses and repair time in the segment workshop can be reduced in comparison with conventional segments. 
     Advantageously, the roller device can be so formed that an additional conduit element is provided in the cross-beam for at least one medium, in particular for feeding cooling medium for a secondary cooling (one-component or two-component cooling), a power supply and/or signal transmission for sensors or switching elements. Advantageously, all feeding and discharge conduits for all media necessary for the rolling device are arranged in the cross-beam in order to be able to carry out complete testing of the module, properly protect all of the conduit elements in the cross-beam, and easily form the module. 
     In order to achieve a more rapid mounting and an easy monitoring, respective medium connectors which communicate with conduit elements in the cross-beam, are provided on the end side, longitudinal side, or rear side of the cross-beam. In this way, it is, e.g., possible to screw the roller device to the segment support and then to connect respective feeding and discharge conduits, e.g., for cooling medium circuit, grease lubricant circuit, power supply, and sensors and switching elements with respective medium connectors on the cross-beam using simple coupling elements. The cross-beam can be so formed that medium connectors are automatically connected with respective conduits when the cross-beam is placed on the segment support. 
     An efficient connection arrangement can be formed with the use of suitable coupling elements such as, e.g., hybrid sockets, water boards with gaskets, coupling tubes with O-rings on opposite sides, and so forth so that the connection of respective feeding and discharge conduits to the roller device can be effected simply and reliably. Advantageously, the sockets, coupling and connectors are so formed that they can conduct simultaneously at least two media. In this way, a respective connection can be formed even more efficiently because the member of coupling elements can be reduced. 
     In order to be able to easily monitor respective medium channels in the cross-beam, those can be provided as milled channels which, e.g., on the rear side of the cross-beam, i.e., on the side of the cross-beam remote from the slab, are closed with a cover, so that for monitoring or cleaning, the cover should be open for monitoring respective cooling medium channels. Open channels, or silicon-sealed channels in which the conduit elements can be laid, can also be provided. Open or silicon-sealed channels are advantageously provided on the side of the cross-beam remote from the slab, i.e., on the “rear side” of the cross-beam. In a further advantageous embodiment, there are provided conduit elements that extend along the cross-beam and are connected therewith. 
     By providing respective medium channels inside the cross-beam, separate tubular conduits and cables, which were laid, in the up to the present state-of-the-art, outside of the cross-beam or extended over the width of the cross-beam, are not laid any more in the dangerous region between the outer bearing housings, so that the danger of damage in case of breakthrough or in case of a high radiation heat within the respective casting machine, can be reduced. 
     Further, by arrangement of the medium channels inside the cross-beam, it became possible to form bow segments with a small roller diameter and a correspondingly small casting radius, which up to the present was complicated and prone to errors or was not at all possible because absence of access for carrying out welding works. With the present cross-beam, casting machines with small casting radii, e.g., from 4000 to 5000 mm, can be produced, wherein the rollers also have a small diameter, e.g., from 120 to 180 mm. 
     Advantageously, with a cross-beam of a proposed form, by placing the cross-beams on the segment frame, the support beams in the segment frame can be eliminated because they are formed by the cross-beams themselves. Correspondingly, each second or each third strut in the segment frame can be eliminated. 
     By laying respective conduit elements inside the cross-beam, a noticeable simplification of the segment frame structure, in which a plurality, e.g., seven roller devices should be received, is achieved because separate tubular conduit connectors for the cooling medium circuit or signal conductors need not be provided or at least not in up to the present, necessary quantity, when the cross-beams are connected one after another in the casting direction. 
     Different signal conductors or lines for different measurement data such as, e.g., bearing force, bearing temperature, strand temperature, cooling medium temperature, flow rate, pressure, humidity, etc., can be received within media feeding and distribution devices. These measurement signals can be taken off at a central location, e.g., on the end side, a section of the longitudinal side, or on the rear side of the cross-beam by, e.g., multi-functional socket, intelligent terminal, data bus connection or any other efficient way and manner, without a need to provide the signal lines to respective sensors outside of the cross-beam housing. Correspondingly, conduit guides can be efficiently formed, and the corresponding signal lines are not located any more in thermally and mechanically dangerous regions of the casting line. 
     Advantageously, the sensors of the roller devices can already be completely pre-assembled, pre-tested, and pre-adjusted in the modular condition, i.e., before the roller device is mounted in a segment because the roller device can be formed as a self-contained system. The function of separate conduits for different media likewise can be completely tested. By modular construction and a complete testing of functions, the mounting times in respective segment are significantly reduced. 
     According to a further advantageous embodiment, a media circuit for secondary cooling likewise can be mounted in the cross-beam. To this end, advantageously, water distribution chambers for nozzles are provided in the roller line, and control valves can be provided in or on the cross-beam in order to be able to turn separate nozzles on and off, e.g., in order to provide secondary cooling for different strand width. 
     It is advantageous to so arrange media connectors for conduit elements on the longitudinal side of the respective cross-beam that upon two cross-beams being pushed against each other, the respective media connectors of the adjacent cross-beams are so connected with each other that they connect the corresponding conduit elements with each other. In this way, e.g., the cooling circuit can be formed continuous from the first roller unit to the last roller unit, forming a quasi series connection, without a need for a separate piping in cross-beams which are inwardly located in a segment. In other words, a cooling medium feeding conduit can be connected to the first roller device so that the cooling medium flows through all of the roller devices located next to each other, and cooling discharge means is connected to the last roller device. In this way, the number of connectors to which cooling medium is fed from outside, is reduced dramatically. Obviously, such a construction is also possible for measurement signals which can be transmitted between two respective roller devices by media connectors, so that a separate connector of a measurement bus on one side of the segment can suffice for taking off signals of all of the roller devices of a segment. 
     In this regard, it could be necessary, because of the cooling medium temperature, e.g., in the region of the inner cooling of the roller or bearing cooling, to provide more connectors within the cross-beam because the through-flow capacity and, thereby, the cooling capacity of the cooling medium can be limited. Correspondingly, a new cooling medium is always fed over the cross-beam width to provide for a uniform cooling capacity. A series connection of separate rollers, at which the same cooling medium passes through all of the rollers of the cross-beam, can also be achieved by corresponding dimensioning of the cooling medium capacity. In the region of feeding of the secondary cooling medium, this problem does not exist, so that the secondary cooling can be formed as a series circuit so that only one connector is provided at the beginning of the segment for feeding the secondary cooling medium. 
     It is advantageous when separate roller devices can be arranged in a row with respect to one or several medium circuits. 
     On the loose side, i.e., on the upper frame of a segment, the cross-beams can be so geometrically shaped that they form at least a portion of paneling of a tunnel cooling chamber. This can be achieved, in particular, by so dimensioning the cross-beams in their transverse direction, i.e., in the casting direction (perpendicular to respective roller axes) that the distance between separate roller devices is small. Correspondingly, the water vapor produced by the secondary cooling can be efficiently removed by respective suction devices, and the corresponding blowers need not be dimensioned so large that the false air which is drawn through slots between cross-beams, remains moderate. In this way, welded-in sheets between the cross-beams provided to form respective cooling chambers, can be dispensed. Also, thereby the efficiency of maintenance and mounting work for separate segments can be noticeably increased. 
    
    
     
       BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
         FIG. 1  shows a schematic perspective view of a roller device having a plurality of roller elements supported on a cross-beam by roller bearings; 
         FIG. 2  shows a schematic side view of a segment on the loose side and which carries seven roller devices; 
         FIG. 3  shows both loose and fixed sides of the segment shown in  FIG. 2 ; 
         FIG. 4  shows a schematic detailed side view of the segment shown in  FIG. 2 ; 
         FIG. 5  shows a schematic perspective view of several roller devices arranged in a row one after another; 
         FIG. 6  shows a schematic side cross-sectional view of the arranged in a row, roller devices shown in  FIG. 5 ; 
         FIG. 7  a cross-sectional view of the roller device shown in  FIG. 1 ; 
         FIG. 8  shows a layout for inner cooling of rollers; 
         FIG. 9  shows a layout for cooling of intermediate bearings; 
         FIG. 10  shows schematically a first embodiment of the secondary cooling with an external feeding; 
         FIG. 11  shows schematically a second embodiment of the secondary cooing with feeding conduits arranged in the cross-beam; 
         FIG. 12  shows schematically the secondary cooling with two different feeding arrangements for controlling the application width 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Below, the present invention will be described in detail on basis of the drawings. In the description, the same elements in the figures are designated with the same reference numerals, and partially, a repeated description of the respective elements is avoided. 
       FIG. 1  shows a schematic perspective view of a roller device  1  having roller elements  10  which are respectively supported in roller bearings  20 ,  22 . To this end, two roller bearings  22  are provided on respective outer sides of the roller device, with bearings  20  provided as intermediate bearings. The bearings  20 ,  22  are connected with a cross-beam  30 , so that the roller elements  10 , the bearings  20 ,  22 , and the cross-beam  30  form a module. The cross-beam  30  extends in the direction of the roller axes of the roller elements  10 . The modular roller device  1  can be pre-assembled and pre-adjusted in a manner shown in  FIG. 1 , so that the roller device can be fitted in an above-arranged machine unit, e.g., a segment of a casting machine. 
     The cross-beam  30  is provided on its end side  32  with a medium connector  40  communicating with conduit elements for a first medium circuit for cooling the bearings  20 ,  22 , a second medium circuit for inner cooling of roller elements  10 , and a third medium circuit for feeding lubricant to the bearings  20 ,  22 . Such a medium connector  40  is likewise provided on opposite end side  32  of the cross-beam  30 . Dependent on the construction. Feeding of the cooling medium for cooling circuits can be provided on one side and on the opposite side, removal of the cooling medium can be carried out. Alternatively, on one side of the cross-beam both feeding and removal can be provided for a section of the cross-beam and on the other side, feeding and removal can be carried out for a respective other section of the cross-beam. 
     Another medium connector  42  communicates with a conduct element provided in the cross-beam for spraying water that serves as a cooling medium for the secondary cooling. For secondary cooling, water is applied to a slab from nozzles  50  provided on the cross-beam. The medium connector  42  which communicates with a conduit element for the secondary cooling, in this embodiment, is provided on the longitudinal side  34  of the cross-beam. In another embodiment, the medium connector  42  can also be used for cooling of bearings or for inner cooling of rollers. This depends, among others, o the layout of conduit elements provided in the cross-beam. 
     A further medium connector  44  in form of data buses is provided on the longitudinal side  34  of the cross-beam  30 . In the roller device  1 , sensors are provided for measurement of different operational parameters, e.g., for measuring the cooling medium temperature in different points of the roller device, the load to which the bearings are subjected, the bearing temperature, the strand temperature, the flow rate, the pressure, humidity, etc. Further, switching devices an be provided for turning on and off, e.g., different sections of the secondary cooling. With the media connector  44 , corresponding signals of the sensors and the corresponding switching command can be transmitted, as well as power supply for the sensor and switches. 
     Different media, e.g., cooling medium for the first cooling circuit for bearing cooling, cooling medium for the second cooling circuit for cooling roller elements  10 , water for the third cooling circuit for secondary cooling of slabs, lubricant for lubricating the bearings  20 ,  22 , hydraulic medium or compressed air medium for hydraulic or pneumatic control, data lines, switching lines, sensor lines, and power supply for the sensors and switches located in the roller device, all are guided within the cross-beam  30 . This is achieved, e.g., by formed corresponding deep hole bores in the solid material of the cross-beam in order to pass signal wires through these deep hole bores. In order to be able to form deep hole bores at large cross-beam width, the bores can be formed from opposite sides. Liquid and gaseous media, e.g., cooling medium for the roller bearing cooling circuit and the circuit for inner cooling of rollers, can likewise be guided through deep hole bores within the cross-beam  30 . The lubricant also can be guided in such deep hole bores. 
     In an alternative embodiment, the conduit elements for the media extend in a media channels milled in the solid material of the cross-beam which are closed with a cover. The availability of milled cooling media channels, which are closed with a cover, has an advantage that the cooling media channels can be easily opened for maintenance purposes and, correspondingly, can be cleaned. With deep hole bores, this cannot be easily done. Also, signal lines, control lines, and power supply lines can be easily put in so milled channels. Moreover, the milled media channels enable an easy access to separate sensor positions. 
     The channels for lubricant that is fed to roller bearings  20 ,  22  can also be formed as deep hole bores or as channels which are milled in the cross-beam and are closed with covers. In this regard, it is advisable to form, for each of the roller bearings, its own lubricant channel so that the lubricant, e.g., oil-air mixture, which is fed from a lubricant distributor, can be separately delivered to respective separate bearings  20 ,  22 . 
     While in the embodiment of the roller device  1  shown in  FIG. 1 , all of the media are guided in the cross-beam, obviously, it is also possible to guide only a portion of the media in the conduit elements inside the cross-beam, and individual media outside of the cross-beam, as known in the state of the art. The decision here is based, among others, on the desired shape of the cross-beam, in particular, its volume. That goes without saying that in a cross-beam having a relatively small volume, only a limited number of media channels can be formed. However, with regard to the present invention, also conduit elements extending along the cross-beam and fixedly connected therewith, should be viewed as located “in the cross-beam.” In this connection, the conduit elements should be seen as belonging to the cross-beam. E.g., if a conduit element is provided in form of a channel extending along the cross-beam and fixedly connected therewith, this conduit element is seen as being located in the cross-beam. Also, a medium conduit extending along the cross-beam and connected therewith, e.g., a control line for transmitting electrical or hydraulic control signals, is seen as located in the cross-beam. 
     In this connection, it is essential that either conduit elements for at least three different media are located in the cross-beam, e.g., channels for the cooling medium for bearings, channels for the cooling medium for roller cooling, and bores for feeding lubricant, or at least one conduit element is provided in the cross-beam for a “new medium,” e.g., cooling medium for inner cooling of rollers, cooling medium for secondary cooling (one-component material or two-component material), hydraulic medium for a hydraulic control circuit, compressed air medium for a pneumatic control circuit, power medium for power supply, power medium for control signals, power medium for electrical measurement signals, power medium for optical measurement signals or electrical or optical bus system. 
     Correspondingly, a greater portion of the media that before was fed by separate tubular conduits from outside, is only delivered to their respective predetermined locations through corresponding channels and bores in the cross-beam  30 . The advantage of this during the mounting of the roller device/consists in that not so many working steps are necessary for mounting of the roller device  1  because it can be mounted as a module. By mounting as a module, in particular, as a complete pre-assembled, pre-tested, and pre-adjusted module, after the securing of the module on a support, only respective media feeding means must be connected with media connectors provided on the module. The corresponding connection can be provided automatically already upon putting the cross-beam on the support. This can be carried out by a junction connector, e.g., socket, coupling, or connection elements or the like without any problem. 
     On the other hand, separate conduit elements in the cross-beam are better protected against mechanical failures, breaking through, and other damages that may occur during the operation of a roller device. Thereby, the reliability is noticeably increased. In addition, the module can be tested and adjusted before being mounted. 
     Dependent on respective used media and dependent on a respective field of use of respective roller devices  1 , the corresponding connectors  40 ,  42  and  44  can be arranged on the cross-beam in different positions. The exemplary arrangement shown in  FIG. 1 , is then advantageous when separate roller devices  1  are mounted in a machine unit, e.g., in a form schematically shown in  FIG. 5 , side-by-side or with cross-beams  30  adjoining one another to form a corresponding segment. In this case, as it further would be explained in detail with reference to the embodiment shown in  FIG. 5 , the arrangement of at least the connector  42  for the secondary cooling medium and the connector  44  for the data bus on the longitudinal side  34  of the cross-beam is advantageous. Thereby, in case when the separate cross-beams are placed next to each other, the connection of respective medium circuits with each other can be achieved quasi automatically. In other words, with cross-beams arranged in a row adjacent to each other, some conduit elements can be dispensed with by undertaking separate wiring and piping steps. Alone, by placing respective cross-beams next to each other, the respective connection of the conduit elements by corresponding connectors is achieved. In this way, even more efficient mounting can be achieved, and the connections or the connectors between separate medium conduits in separate cross-beams are arranged in a secure position in a protective manner between the cross-beams. 
     In this embodiment, separate media connectors are corresponding seriesly connected. Such series connection is completely without problems, e.g., in case of bus lines because here, a very large number of signals can be communicated to the same bus. In case of a secondary cooling, the series connection is likewise possible without problems, because the secondary cooling medium along the casting direction is not substantially heated, and a continuous flow of the secondary cooling medium from the first to the last roller device of a segment can be provided. 
     With regard to cooling of the roller bearings  20 ,  22  and cooling of the respective roller elements  10 , such a series connection of roller devices  1  is also possible. Here, however, one should take into account that an increased amount of heat that should be removed by cooling. Correspondingly, with the series connection, it may so happen that for the last roller device in the corresponding series connection, no adequate cooling power is available, possibly because of already undertaking heating of the cooling medium. Correspondingly, in order to be able to make available adequate cooling power for each separate cooling device, in the embodiment of the medium connector  40  shown in  FIG. 1  and which is provided on the end side  32 , there are provided connectors for delivery of cooling medium for roller bearings  20 ,  22  and cooling medium for inner cooling of the roller elements  10  so that for each roller device  1 , a separate cooling medium supply is available for these primary cooling circuits. 
     It is further proposed to separately deliver lubricant to each respective above-mentioned roller bearing  20 ,  22 , from lubricant supply for a respective roller device  1 , which lubricant is fed from a lubricant distributor. Correspondingly, in the embodiment shown in  FIG. 1 , there are provided, on the end side  32  of the cross-beam  30 , connectors for lubricant distribution. 
     However, other arbitrary meaningful combinations and positions for respective medium connectors for feeding and removing media on the cross-beam  30  are possible, which can take into account other consideration. E.g., it is conceivable to provide the sockets and fluid connections not only in the end sections of the cross-beam  30  on the longitudinal side  34 , but rather those can obviously be provided in the region of the inner cross-beam sections which, e.g., are designated with a reference numeral  3   b . Even in such a case, by simply pushing the cross-beams  30  during mounting to form a larger unit, respective connectors and couplings can be quasi automatically connected with each other. 
     In this regard, it can be suggested to place separate connectors on the rear side  38  of the cross-beam  30 , i.e., on the side of the cross-beam  30  remote from the slab to thereby achieve both an advantageous layout of respective connectors for assembly purposes and also, e.g., to be able to make, e.g., shorter channels or deep hole bores, in the cross-beam. When the medium, e.g., is fed from outside of the rear side  38  in the middle region of the cross-beam  30 , respective necessary extension lengths can be reduced by half. 
       FIG. 2  shows a schematic side view of a section of a segment  100 , wherein the loose side of the segment  100  is shown in the figure. A corresponding complementary device is provided on the fixed side, wherein here, correspondingly, likewise seven roller devices are provided. This is, e.g., is also shown in  FIG. 3  which shows the loose side and the fixed side of the segment  100 . 
     The segment  100  has a segment frame  110  on which seven roller devices  1 , which are similar to the roller device  1  shown in  FIG. 1 , are mounted. Respective media supplies and media connectors  40  are not yet closed by respective sockets or connection pieces in the condition of the segment  100  shown in  FIG. 2 . Further, media connections are located on the rear side of respective roller devices  1  so that they extend within the segment frame  110 . 
     Separate roller devices  1  are mounted on the segment frame  110 , respectively, as a complete module. In other words, separate roller devices  1  need not be assembled on the segment frame of separate parts, but rather a pre-assembled roller device  1  that includes the cross-beam  30  and roller elements  10  pre-mounted thereon with aid of bearings  20 ,  22 , is directly mounted, as a module, on the segment frame  110 . After mounting of the roller devices  1  on the segment frame  110 , a connection of respective media feeding conduits and media discharge conduits to coupling elements provided therefor must be timely carried out. 
     In particular, a respective segment  100  can be formed by securing the roller devices on a respective segment frame with bolts and/or screws, wherein some of the media conduits become connected by placing the cross-beam on the segment frame. Other media conduits are become connected, after placing, using socket and coupling connections. Correspondingly, a cumbersome separate tubing and wiring of the cross-beams is eliminated. Obviously, the tubing and wiring of the segment frame are still carried out and are available. 
     With the proposed integrated cross-beam, only casters with a small casting radius, e.g., from 4000 to 5000 mm can be formed, wherein the rollers also allow a small roller diameter, e.g., from 120 to 180 mm. With simple attachment of media to the rear side of the cross-beams or to an end side of the cross-beams, the connection of media is obtained even at these small radii. Previously, the small radii were not possible because an access for welding of respective media feeding conduit was not available. 
     Advantageously, with the proposed shape of the cross-beams, also, putting of the cross-beams on support cross-beams in the segment frame can be eliminated because those are formed by the cross-beams themselves. Correspondingly, in the segment frame, each second or each third strut is eliminated, whereby the segment frames can be easily formed. 
     An eventually damaged roller device  1  within the segment  100  can in this way be relatively simply and rapidly replaced because here, simply respective coupling or other connections are removed, and a modular roller device is inserted. The separate replacement of the roller device typically takes place after the entire segment in a respective strand guide has been removed. The replacement of the roller device then takes place in the segment workshop. 
     Further, the so formed modular roller devices  1  can be held on a frame and quickly and efficiently be substituted for when needed. In addition, the error rate during mounting is smaller because the roller devices are already formed as self-containing systems that simply should be connected with provided to this end, coupling and connector elements. 
     The operational reliability of the plant and the efficiency of the maintenance is further increased as each roller device  1 , as a complete module, which has primary cooling circuit, lubricant circuit, secondary cooling, and data transmission elements, is completely formed, pre-tested, and pre-adjusted before installation. In particular, the roller layout already can be adjusted in the modular condition, so that alignment and adjusting works can be reduced to a minimum during the installation of the respective roller device  1  in segment  110 . 
     From the proposed construction, it follows that the accessibility of each roller device can noticeably be increased because a separate tubing completely or to a greatest extent can be eliminated as well as a separate wiring. In particular, all of the media and data conduits run inside the cross-beam that represents a self-containing unit, in particular then when they are milled out form a solid material. Thereby, the danger of strain fractures at a separate tubing due to different thermal expansion coefficients or different components is reduced because separate channels and deep hole bores are provided in a quasi monolithic cross-beam  30 . 
       FIG. 4  shows schematically a side view of a segment  100  wherein only one separate roller device  1  that has three roller elements  10  supported by respective roller bearings  20 ,  22 , is visible. The secondary cooling with nozzles  50  which are shown by solid line extending over the width and which can apply cooling medium to the slab, is clearly shown. With control valves provided in the cross-beam, separate sections of the secondary cooling can be turned on and off. 
     The media connectors  42  provided on a rear side  38  of the cross-beam  30 , are shown in this semi-cross sectional view. It is further shown that feeding of the cooling medium for inner cooling of the rollers from the cross-beam  30  in the roller elements  10  takes place via side feeders  12  which are connected with the cross-beam and extend through the cover of the roller supports into the roller elements  10 . 
       FIG. 5  shows a further segment  100 ′ wherein separate roller devices  1  adjoin each other side-by-side, with the cross-beams  30  being put up against adjacent beams along their longitudinal sections  34 . In this way, it is immediately insured that the media connectors  42  for the cooling medium so adjoin each other that the flow of the secondary cooling medium through all of the roller devices is possible, without the need to carry out an additional external tubing. The same is the case with regard to data buses, wherein here the media connector  44  likewise are so arranged on the longitudinal side  34  that upon putting two roller devices  1  next to each other, an automatic electrical connection between respective data bus connectors  44  takes place. 
     On the rear side  38  of the cross-beam  30 , a milled-in cooling medium channel  52  is seen in  FIG. 5 . By mounting the cross-beams  30  on the segment frame  110 , which is not shown in  FIG. 5 , or by providing a separate cover that covers the milled cooling medium channel  52 , an easily accessible and maintenance-friendly cooling medium channel is provided and which is protected within the cross-beam  30  but, nevertheless, can be easily monitored. The shown cooling medium channel  52  represents conduit means for guiding the medium for cooling of bearings. In principle, such channel  52  milled-out in a solid material, can be formed for receiving every other medium, in particular for receiving electrical or hydraulic medium conduits. 
       FIG. 5  further shows the formation of a roof of a tunnel cooling chamber with cross-beams  30  extending side-by-side, wherein the intermediate spaces  60  between the respective roller devices  1  or their cross-beams  30  are so filled with separate sheets  62  that here a quasi closing cover is provided on the loose side of the segment. In this way, water vapor which is formed in the tunnel cooling chamber, can be efficiently removed, without a need to provide an overdimensioned blower that should deal with a large amount of infiltrated air. 
     Advantageously, the roof further includes additional covers which close, in particular, the channels  52  and which are secured with suitable mechanical means, e.g., with screws. Thereby, the rear side  38  of the cross-beams  30  is suitably sealed. As a result, a so-called reclosable roof is provided. 
     Alternatively, the channel  52  can be covered when the roof, on the rear sides  38  of the cross-beams  30 , is closed with silicon, whereby the channels  52  are suitably sealed. 
     Also, instead of the separate sheets  62  which generally are formed by welded-in sheets provided on the segment, the cross-beam  30  itself can be so shaped that it adjoins an adjacent cross-beam so tightly along the entire casting width that a quasi universal cooling chamber is formed. To this end, the cross-beam should be so stretchable out and deformable in its transverse direction, i.e., in the casting direction that it forms, together with a respective adjacent cross-beam, as continuous structure as possible. 
       FIG. 6  shows again a schematic cross-sectional view of a section of the segment of  FIG. 5  and which clearly shows closing of the intermediate spaces  60  between separate cross-beams  30  with inserted sheets  62 . In this way, a tunnel cooling chamber can be efficiently formed. As it has already been shown, the cross-beam  30  can so be formed in the casting direction that the inserts  62  can be eliminated as separate cross-beams adjoin each other clearance-free to a most possible extent. 
       FIG. 7  shows a cross-sectional view of a roller device  1  in the region of the roller bearing  20 . A cross-sectional view of the cross-beam  30  is likewise shown. In the cross-beam, three conduit elements  310 ,  320 ,  330  which are formed in the solid material of the cross-beam  30  as deep hole bores, are provided. The conduit elements  310 ,  320 ,  330  serve, in the embodiment shown, for conducting the cooling media and lubricant. The conduit element  310  serves for conducting of the lubricant for the bearing  20 . The conduit element  320  transports the cooling medium for inner cooling of the roller. The conduit element  330  transports the cooling medium for cooling the bearing  20 . 
     In the cross-beam, there is further provided a conduit element  340  in form of a channel that opens to the back and is milled in the solid material of the cross-beam  30 . A conduit  342  for hydraulic control is placed in the channel. Further, in the cross-beam  30 , there is provided a conduit element  350  in form of a channel extending along the cross-beam  30  and fixedly connected therewith and in which a bus system  352  is located. 
     Correspondingly, in the cross-beam  39  the conduit element  310 ,  320 ,  330 ,  340 ,  350  are provided for at least three different media. 
       FIG. 8  shows schematically a layout of flows of the cooling medium for an inner roller cooling with a separate inflow for each cross-beam  30 . The cooling media is fed in a corresponding conduit element in the cross-beam  30  via a distributor  400  and an associate medium connector  40 . After the cooling medium passed through the rollers  10 , it is picked up again by a distributor  420  provided on the opposite side and is removed. The process correspondingly is carried out for a row of separate roller devices. 
       FIG. 9  shows an example of cooling of the roller bearing  20  in particular the middle bearing  20 , analogous so that of  FIG. 8 . The cooling medium against is fed in respective cross-beams  30  via a distributor  410  and then is transported by the conduit element provided in the cross-beam  30  to the middle bearing  20  and then, by the conduit element to the outlet distributor  420 . 
       FIG. 10  shows schematically distribution of the cooling medium for the secondary cooling. The layout corresponds essentially to that shown in  FIGS. 8 and 9 , namely, the cooling medium for the secondary cooling is fed to the cross beams  30  via the distributor  410  and then to the nozzles  50  of the secondary cooling. 
       FIG. 11  shows a variant of the secondary cooling, here, the cross-beams  30  are so arranged that they contact each other, and have conduit elements with medium connectors  42  corresponding to medium connectors  42  shown in  FIG. 5 . Correspondingly, by an arrangement of contacting each other cross-beams  30 , it is achieved that the header  410 ′ inside the cross-beams  30  is formed. Separate conduit elements for distributing the secondary cooling medium correspondingly branch from the header  410 ′. In this embodiment, the secondary cooling medium takes place over the entire width of the cross-beam. 
       FIG. 12  shows a modified embodiment of  FIG. 11  in which there is provided a first header  410 ′ and a second header  410 ″ for the secondary cooling, and wherein the first header  410 ′ supplies the central nozzle  50 ′ with the cooling medium, and the second header  410 ″ supplies the outer nozzles  50  with the cooling medium. In this way, the distribution of the second cooling medium can be purposefully controlled.