Tundish carriage with a lifting device for a tundish

A tundish carriage with a lifting device (1) for a tundish (2) for liquid steel materials, in particular in a multi-strand caster, wherein the tundish (2) is supported, with a possibility to be lifted or lowered, by controlled electromechanical or hydraulic lifting devices (1a, 1b) on a carriage frame (7), prevents a quadruple arrangement of piston-cylinder units and a complicated synchronization control, with security for personnel and a noticeable simplification of construction, by providing a single vertical support (9) and only two lifting devices (1a, 1b).

The invention relates to a tundish carriage with a lifting device for a tundish which is displaceable on a teeming platform that is located above a continuous casting mold of a continuous casting machine for a liquid cast metal such as, e.g., a liquid steel material, on a pair or rails and is adjustable, in particular for a multi-strand casters, wherein the tundish is supported, with a possibility of being lifted or lowered, by controllable electromechanical or hydraulic lifting devices on a carriage frame.

Known are tundish carriages with electromechanical (motor-driven spindles), which carry four lifting devices (DE 25 57 769 A1 or EP 0 940 205 B1). The four lifting devices must maintain synchronous movement and be displaceable over the same path. In one of the embodiments, the lifting devices are formed as hydraulic piston-cylinder units which likewise must be displaced synchronously over equal paths. For their control, an expensive synchronization control system is necessary. Upon failure of the synchronization regulation or control system, inclinations of the tundish occur, endangering not only the personnel but also the caster.

The object of the invention to eliminate a fourfold arrangement of the lifting devices and the complicated synchronization regulation and/or control and to achieve an increased security for the personnel, together with the simplification of the construction and reduction of investment costs.

The set object is achieved according to the invention in that the carriage frame, which is provided with displacement drives and running wheels on one or both sides and is formed of longitudinal and cross-beams, contains only one vertical support for the tundish between only two cross-beams, which is supported with respective pairs of arms on arranged in pairs side supports on only two lifting devices which are arranged and secured on respective longitudinal beams of the carriage frame. The advantage consists in that only one pair of hydraulic lifting devices and only one vertical support for the tundish are necessary. The known up to now synchronization regulation is not any more necessary. The simultaneous actuation of the piston-cylinder drives can be effected sufficiently precisely with simpler means.

According to an embodiment of the invention, the supports on the lifting devices are formed of coaxial rollers. This construction noticeably simplifies the design and facilitates the adjustment of the vertical support.

A further improvement consists in that on both lifting devices which are formed by hydraulic piston-cylinder drives, the supports are provided on respective cylinder housings.

It is further provided that a tilting table for the tundish longitudinally displaceably in the vertical support, forms, in the transversely displaceable vertical support, a loose side, and the vertical support has symmetrically arranged pairs of support points for the tundish. Thereby, deformation of the tundish, which occur during an operation, can be compensated. In addition, a symmetrical force application is insured.

Another feature consists in that the tilting table, which is provided in the vertical support on the loose side, is supported in the vertical support at both ends with a springy supports. Thereby, an elastic adaptation of the tundish position after an extended operational period becomes possible.

According to further features, positioning of the tilting table and force transmission for changing the position is effected so that the tilting table is supported on the loose side in the vertical support for pivotal movement about a cross-axle extending parallel to the cross-beams. Thereby, force transmission to the fixed side can be effected with a connection rod.

According to further improvement, of a particular importance is a connection of the two hydraulic lifting devices, instead of a hydraulic synchronization control, by a hydraulic flow divider to a common feeding conduit. This permits to eliminate to a most possible extent the problem of the hydraulic synchronization control, which existed up to the present. With a flow divider, only small tolerances are associated which, in the present case amount to about 2% (synchronization tolerance), and a reliable operation is insured. With recalculation for a stroke of, e.g., 650 mm, the deviation amounts to only 26 mm which, however, proved to be acceptable at calibration in lower and upper positions. In addition, a sufficient reliability can be provided with additional monitoring of the displacement with path sensors mountable on the cylinders. Thereby, the deviation of 2% per stroke remains always the same and does not change.

The flow divider is formed of electromagnetically controlled valves. Thereby, a repeatable regulation or control per stroke is provided.

According to further features, for supplementing the basic concept, an additional function can be provided by arranging in the support points on the vertical support for the tundish with a defined load introduction, load cells as a weighing device.

Alternative thereto as a weighing device, pressure in the cylinders of the hydraulic lifting devices is measured, and the tundish weight is determined by conversion.

According to other features, the position of the tundish can be influenced by an adjusting device, which is secured on the vertical support on the fixed side and is provided on a rail side.

For further adjustment, on a rail side opposite the adjusting device, a device for cross-adjustment of the tundish is provided. Both sides are connected with each other by axial transmitting means such as e.g., rods.

For determination of displacements and forces necessary for adjustment of the tundish, the adjusting device on the loose side and a compensation device on the fixed side are connected with each other by thrust-transmitting means.

The device for cross-adjustment of the tundish engages the arms of the vertical support and is supported on the lifting device.

In the drawings embodiments of the invention are shown which will be described in detail below.

A tundish carriage (FIG. 1) is equipped with a lifting device1for a tundish2and displaces on a teeming platform3, whereby the tundish2is displaced on a pair of rails6a,6bover a continuous casting mold4of a continuous casting machine5, which passes, beneath the teeming platform3, in a back-up rolling mill stand with a cooling chamber, for liquid cast metal such as, e.g., liquid steel, and is adjusted against walls of the continuous casting mold4by a pouring tube that projects downward into the continuous casting mold4beneath the metal level. For cooling, in the continuous casting mold4, of a cast strand that solidifies from outside inward, it is very important that the pouring tube is equidistantly spaced from the mold wall along its circumference. In the shown embodiment, the tundish2is supported with lifting devices1a,1bon a carriage frame7and for start of casting after a preheating, is lowered to a correct casting height into the continuous casting mold4and after a conclusion of a casting process that can last for hours or days, is lifted again.

Up to the present, with tundishes having electromechanical or hydraulic lifting mechanisms, lowering, adjustment and lifting again could be carried out only inadequately because of the large volume of the mechanical and/or hydraulic devices. In addition, long-lasting deformations of the tundish, which occur during an operation cannot be sufficiently compensated. Therefore, it is important that the carriage frame7, which is provided with displacement drives8and running wheels8aon one or both sides and is formed of longitudinal and cross-beams7a,7b,contains only one vertical support9for the tundish2between only two cross-beams7b,which is supported with respective pairs of arms9a,9bon arranged in pairs, side supports10a,10bwhich are provided on both lifting devices1a,1bwhich are arranged and secured on respective longitudinal beams7a,7aof the carriage frame7.

The side supports10a,10bof the vertical support9for the lifting devices1a,1bconsist of coaxial rollers11a,11b.The vertical support9forms a loose side14a(FIG. 1, left side) and a fixed side14b(FIG. 1, right side). A tilting table12, which extends in the direction of the longitudinal beam7asupports the tundish2. The function of the tilting table12will be described in detail below. On the vertical support9, there are further provided support points13a,13b,13c,and13don which the tundish2is supported. As it will be mentioned below with reference toFIGS. 7A and 7B, the tilting table12, which is located on the loose side14a,is supported in the vertical support9with compression springs (plate springs), the tilting table12without the tundish2is held horizontally and forms a compensating support15. With the inserted tundish2, the position compensation is effected automatically. In addition, the tilting table12pierces a transverse axis16(FIGS. 1A,6A,7B) which forms a displacement axis38and which would be mentioned and described in more details in another connection.

The tundish carriage, which is displaceable on rails6aand6b,can have displacement drives on one side, as shown inFIG. 1B. While the carriage frame7, which is formed of the longitudinal beams7aand cross-beams7b,have, e.g., a length of 4,000 mm, the tundish2with a length of about 8,000 mm projects beyond it in the shown embodiment of a double-strand continuous caster (FIG. 1B). The support points13athrough13don the vertical support9can be provided either with dammy support bodies or, in case when the tundish2is weighted, should be provided with load cells which form a weighing device20(FIG. 6B). The ladle39is located above the tundish2during casting. For adjustment of the side distance of the pouring tube (seeFIG. 8) relative to the walls of the continuous casting mold, the lifting device9is supported on the rollers11aand11bon the fixed side14band can be adjusted on the loose side14ain a casting direction with cross-adjustment device25.

While the view from right to left (FIG. 1B) is shown inFIG. 3,FIG. 2(FIG. 1B) shows a view from left to right.FIG. 2shows, in addition to the tundish carriage displaceable on the teeming platform3in a displacement direction8bby the displacement drives8on the running wheels8a,displaceable platforms26with arranged thereon cable arms27. The cable arms27include conductors for electricity and conduits for necessary for operation, media (such as, e.g., hydraulic fluid, protection gas, compressed air, etc.).

FIG. 3(view from left to right inFIG. 1), shows, in addition to the hydraulic lifting device1b,the tundish2, in addition, an overflow nozzle28and an overflow spout29which adjoins the tundish2, wherein in addition to the running wheels8aon the carriage frame7, the attached frame7for the overflow spout29runs on one of the rails6aor6busing a support wheel30.

In order to replace disadvantageous, expensive and laborious synchronization regulation or control, according toFIGS. 4A and 4B, there is provided, for both available hydraulic lifting devices1aand1bwith cylinders1c,a flow divider17connected with a feeding conduit17aand formed of control valves18aand18b,wherein both control valves18aand18bare controlled by a controllable electromagnetic valve18c.The control resolution amounts to about ±2% which at a stroke of about 650 mm, comes to 26 mm, insuring a great reliability and a clearer conception with a greater cost-effectiveness than the conventional synchronization control with large electronic and switching costs. Stroke monitoring can be carried out with two displacement sensors31which are adequate for sensing reliably displacement in the cylinder1c.

FIG. 5shows the tundish2on the carriage frame7with the longitudinal beams7aand cross-beams7band which is displaceable on the rails6a,6b.The tundish carriage serves a double-strand continuous caster21, wherein both strands are characterized by midpoint3b(strand1) and midpoint37(strand2). The ladle39(not shown there) finds itself above a protective runner-box35. An adjustment device22is located on the fixed side14b.A cross-adjustment device25is located on the loose side14a.The adjustment22is thus located, in the double-strand continuous caster21, on a rail side23and is attached to the lifting device1a.The adjusting device22is used in particular with a double-strand tundish2and serves for aligning the pouring tube in the midpoint37of the cast strand2, i.e., in the continuous casting mold4for compensating support tolerances and spout deformations. There is further provided a compensation device32having an adjustment stirrup34supported on the vertical support9and against the lifting device1a and adjustable, within certain limits, by a pivot cylinder33. The retention of the tilting table12is effected with a cross-axle16secured on the vertical support9. The adjustment stirrup34is connected with the vertical support9. Thus, the complete vertical support9can be pivoted and, thereby also the tundish2, i.e., the transfer is effected over the loose side14a(tilting table12) and the fixed side (14b). This re-adjustment is advantageous for tundishes that operate for a long time and a position of which has been changed somewhat by deformation of the brick lining. The cross-adjusting device25displaces the vertical support9transverse to the displacement direction8bin opposite directions. The cross-adjusting device25is provided on a rail side24located opposite the adjusting device22for cross-adjustment of the tundish2. The device25for cross-adjusting of the tundish adjoins the arms9a,9bof the vertical support9and is supported against the lifting device9(actually the lifting device1b—Translator's remark).

FIG. 6Ashows the hydraulic devices1a,1band a connecting them, vertical support9defining the loose side14aand the fixed side14B, and the tilting table12that extends transverse to the vertical support9. The tilting table12is supported on the cross-axle16secured in the vertical support9. InFIG. 6Bthat shows the tundish carriage without the tundish2, the adjusting device22, and the cross-adjusting device25, in addition to the loose sides14aof the lifting devices1a,1band in addition to the fixed sides14b,the load cells19are shown which form a weighing device20, in case such is considered to be appropriate at this point. As the weighing device, the fluid pressure, which prevails in the cylinders1cof the lifting devices1a,1b,can be measured and lead to a conclusion regarding the tundish weight in the course of conversion. In this case, the load cells19can be replaced by dammy pieces of equal shape and dimensions.

FIGS. 7A and 7Bshow the vertical support in perspective and separately, without the surrounding it, components. On the fixed side14band the loose side14a,in case of provision of the weighing device20, the load cells19, which form the same, are shown. The tilting table12is displaceable in the vertical support9and is supported against a springy support15. The vertical support9, which is formed of two side walls and cross-streets, has, for the springy support15(that can consist of compression springs or plate spring packages), a necessary angle-shaped recess that can also be clearly seen inFIG. 1A. InFIG. 7B, the vertical support9, together with the tilting table12, is shown from the opposite direction.

FIG. 8shows a partially cross-sectional, transverse to the displacement direction, view of the tundish carriage in the operational position. On the teeming platform3, the tundish carriage is brought in a position by the displacement drive8and is secured there. After lowering of the preheated tundish2with the submerging outlet, the midpoint37of the strand2becomes submerged. With the increase of an operational time, the tilting table12serves for compensation of the mentioned sprout deformations. The adjustment and, thereby, subsequent readjustments of the tundish2is effected with the cross-adjusting device25and the adjustment device22.

The displacement axis38of the tilting table12can be seen. A filled ladle39is displaced over the runner-box35, and the discharge can begin.

In the tundish carriage, the accompanying platforms26and the cable arms can be recognized. The adjusting processes can be effected from the accompanying platform26with the lifting device1aand the cross-adjusting device25located adjacent thereto.

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