Slide gate nozzle or shut-off control valve for metallurgical vessel and refractory shut-off parts thereof
BACKGROUND OF THE INVENTION 
     The invention relates to a slide gate nozzle or shut-off control valve to be mounted in a wall or lining of a vessel containing, in particular, molten metal and including at least two refractory shut-off parts that are provided with passages or openings, that project into the vessel interior and that have respective sliding surfaces that can be displaced sealingly relative to one another. The invention also relates to refractory shut-off parts for such nozzle or valve. 
     A final control supply element of the above described category is disclosed in German DE-P 35 40 202 and substantially comprises two concentric tubes or pipes that project into the vessel, that can be moved therein relative to one another and that have openings through which the melt passes. The openings of the pipes can be brought more or less into alignment or coincidence by means of axial lifting movement and/or rotary movement. Thus, it is possible to correspondingly regulate the volume of molten metal discharge. The two refractory pipes must be machined quite accurately in the surface regions thereof that are in contact with each other in order to obtain an absolute seal. The machining of these cylindrical rotational surfaces is, therefore, relatively time-consuming. In addition, the risk of breaking the pipes off during assembly and also during operation is relatively high due to possible generation cross forces. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to further develop a slide gate nozzle or shut-off control valve of the aforementioned type in such a manner that its shut-off parts can be manufactured in a simpler manner and thus more cost effectively, and in addition to obtain a higher operational reliability. 
     This object is achieved in accordance with the invention in that each shut-off part within the vessel has at least one approximately planar sliding surface. The two shut-off parts can be displaced sealingly relative to one another at such planar surfaces in order to open or close passages of openings through the parts. The planar sliding surfaces can be manufactured in a simple manner and guarantee optimal operational reliability. 
     In an advantageous embodiment of the invention, one shut-off part is mounted stationarily in the vessel and the other, part is displaceable within the vessel. Both shut-off parts can be provided with one or two parallel sliding surfaces. 
     In a variant, the stationary shut-off part has a recess within which is received a plate to open or close the discharge openings. 
     The invention also is quite suitable for thin slab casting wherein the passages or openings are designed in the shape of elongated slots. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments and other advantages of the invention are explained in detail, with reference to the accompanying drawings, in the following description: 
     FIG. 1 is an axial sectional view of a slide gate or shut-off nozzle according to the invention; 
     FIG. 2 is a transverse cross-sectional view of the slide gate nozzle according to FIG. 1, the upper half of FIG. 2 being taken at an axial position through a lateral passage and the bottom half of FIG. 2 being taken at a position below such passage; 
     FIG. 3 is a perspective view, in axial section embodiment of the invention; 
     FIG. 4 is an elevational view of the slide gate nozzle of FIG. 3 and a drive unit therefor mounted on a vessel; 
     FIG. 5 is a partial section taken along line V-V of FIG. 4; 
     FIG. 6 is an axial sectional view of another embodiment of the invention; 
     FIG. 7 is a view taken along line VII--VII of FIG. 6; and 
     FIG. 8 is a perspective view, in transverse section an embodiment with slotted passages. 
    
    
     DETAILED DESCRIPTION OF INVENTION 
     FIG. 1 shows a slide gate nozzle or shut-off valve 10, arranged in a lining 13 of a vessel 12 to contain molten metal or a distributor for use in a continuous casting installation. Shut-off valve 10 substantially comprises a stationary refractory shut-off part 11 and a moveable refractory shut-off part 15 guided for movement axially or longitudinally in stationary refractory shut-off part 11. The stationary part 11 includes a cylindrical sleeve-shaped portion 14 embedded in the refractory vessel bottom and a plate-shaped extension 16 that projects into the vessel interior and that has a planar sliding surface 17 extending parallel in the direction of displacement of moveable part 15. Surface 17 makes sealing contact with a planar sliding surface 18 formed by a segmented recess in moveable part 15. By displacing shut-off part 15, a transverse passage 19 extending through the plate-shaped extension 16 can be brought more or less into alignment with a passage 19&#39; extending through part 15. Displacement of part 15 vertically can be achieved by a drive (not shown) to thereby makes it possible for the molten metal within the vessel to flow through passage 19 and then through opening 19&#39;, for example, into a continuous casing mold. FIG. 2 shows also the planar sliding surfaces 17, 18 of shut-off parts 11, 15. 
     Slide gate nozzle or shut-off valve 20 of the embodiment of FIG. 3 has a stationary refractory shut-off part 23 that is cemented into a ladle bottom 22, shown only partially. Part 23 is rectangular and has two opposite parallel sliding surfaces 25 and 26. Sliding surfaces 25, 26 make sealing contact with respective sliding surfaces 27 and 28 of a U-shaped moveable refractory shut-off part 24 that can be adjusted in a height or vertical direction 29 and that has in each vertical leg thereof an opening 32. Opening 32 thus can be aligned with a passage 33 extending through stationary shut-off part 24, thereby to open valve 20. 
     FIG. 4 shows slide gate nozzle or shut-off valve 20 mounted in ladle 22 with a related drive unit. The vertically adjustable shut-off part 24 can be displaced by means of linkage 36 by a drive 35 in the form of a piston-cylinder unit that is mounted laterally on ladle 22 by a hinge 37 and by setscrews 38 operable to adjust the axis of drive 35 to be parallel relative to that of shut-off part 24. A refractory rod 31 extending from shut-off part 24 is held by a bolt 43 at linkage 36 such that it is fixed vertically relative to the sliding surfaces 27, 28 with adequate play relative to the direction of sliding surfaces 27, 28, as shown in FIG. 5. Thus, it is ensured that shut-off part 24 will not break off, on the one hand, and is positioned with respect to the stationary shut-off part 23, on the other hand. With respect to this positioning, rod 31 has on its upper end two stop faces 41 and 42, which make it possible to center rod 31 in a recess 39 of linkage 36 without any play. Shut-off part 24 could be displaced just as well horizontally or in a swivel movement in order to regulate valve 20. 
     Slide gate nozzle or shut-off valve 50 shown in FIGS. 6 and 7 includes a refractory shut-off part 53 that is stationary in vessel bottom 52 and that has a passage 55 that extends into the vessel interior laterally and that then extends vertically through an additional sleeve 56 or a casting pipe outwardly of the vessel. The stationary shut-off part 53 has a recess 57 that intersects the lateral portion of passage 55 and in which is mounted a refractory plate 54 that can be displaced sealingly. The molten metal can be poured in a controlled manner through longitudinal and/or swivel movement of plate 54 to align a cross opening 55&#39; thereof with passage 55. Plate 54 also has a refractory extension 58 and can be displaced in a manner similar to the structure shown in FIG. 4. Rod 58 also could be guided laterally or downwardly out of the vessel or ladle. 
     Slide gate nozzle or shut-off valve 60 shown in FIG. 8 differs from that of FIG. 3 only to the extent that its refractory shut-off parts 63 and 64 are elongated and that respective passages 65 and 66 thereof are elongated and slotted. In particular when casting thin slabs, there is a need when casting a strip to shape the discharge passage or opening 66 from a vessel 62 in the form of a slot. In the opening position the passages or openings 65 of the moveable shut-off par 64 that extend in the horizontal direction align with portions of passage or opening 66 that extend transversely and from there to a vertical portion of passage 66. Through height adjustment 67 of part 64 a precisely metered volume of melt can be discharged from the vessel in the shape of a strip. 
     Further, the embodiment of FIG. 8 could be arranged with the axial portion of passage 66 extending approximately horizontally out of the ladle. In such an arrangement, the sliding surfaces of both shut-off parts 63 and 64 would enable approximately horizontally within the vessel. 
     Other variants of the invention also are possible. Thus, it is conceivable that, for example, with the slide gate nozzle of FIG. 3 that upper shut-off part is stationary, whereas the lower shut-off part can be moved longitudinally in the vessel bottom.