阅读说明：本技术 具有嵌入式机械手的机器人化钢包运输装置系统 (Robotic ladle transport device system with embedded manipulator ) 是由 达米恩·德尔森 让－卢克·雷纳德 于 2021-03-30 设计创作，主要内容包括：本发明涉及一种金属浇铸设备,包括：装载平台(20)、中间包(1)、第一钢包(11)和第二钢包(12)和第一机械手和第二机械手(35),钢包包括：底板、钢包长水口(13a-13c)和钢包滑动水口机构(15),钢包滑动水口机构与用于在密封位置与浇铸位置之间致动钢包滑动水口机构的驱动装置(17)联接,机械手用于将所联接的钢包长水口固持在钢包的下水口(14)上,金属浇铸设备还包括机器人(21),其用于：将新钢包长水口交给位于装载工位处的钢包的机械手,以及优选地将驱动装置联接到钢包滑动水口机构,每个机械手相对于相应的第一钢包或第二钢包是固定的,以便与相应的第一钢包或第二钢包一起在装载工位与浇铸工位之间移动。(The invention relates to a metal casting device, comprising: loading platform (20), middle package (1), first ladle (11) and second ladle (12) and first manipulator and second manipulator (35), the ladle includes: a bottom plate, a ladle shroud (13a-13c) and a ladle sliding gate valve mechanism (15) coupled with a drive means (17) for actuating the ladle sliding gate valve mechanism between a sealing position and a casting position, a robot for holding the coupled ladle shroud on a collector nozzle (14) of a ladle, the metal casting apparatus further comprising a robot (21) for: the method comprises the steps of handing a new ladle shroud to a manipulator of a ladle at a loading station, and preferably coupling a drive arrangement to a ladle slide gate mechanism, each manipulator being fixed relative to a respective first or second ladle so as to move with the respective first or second ladle between the loading station and the casting station.)

1. A metal casting apparatus comprising:

(a) a loading platform (20),

(b) a tundish (1) is arranged in the middle,

(c) a first ladle (11) and a second ladle (12), each of the first ladle and the second ladle comprising:

a base plate provided with openings (11o, 12o),

ladle shroud (13a-13c),

-a ladle sliding gate valve mechanism (15) comprising a drain (14) configured for reversibly receiving and supporting the ladle shroud, the ladle sliding gate valve mechanism (15) further being configured for coupling with a drive arrangement (17) for actuating the ladle sliding gate valve mechanism between a sealing position, in which the opening is sealed, and a casting position, in which the opening is in fluid communication with the ladle shroud (13a-13c),

(d) a first ladle long nozzle manipulator and a second ladle long nozzle manipulator (35) which are respectively used for fixing the connected ladle long nozzles (13a-13c) on the down nozzles (14) of the first ladle and the second ladle,

(e) a transport device comprising a turntable (30) or ladle carriage, the transport device comprising at least a first and a second holding device for holding the first and second ladles (11, 12), respectively, wherein the transport device is configured for moving the first and second ladles (11, 12) between a loading station adjacent to the loading platform (20) and a casting station above the tundish (1) and holding the first and second ladles (11, 12) in place,

it is characterized in that the preparation method is characterized in that,

-the metal casting plant comprises a robot (21) configured for carrying out the following operations on the first or second ladle (11, 12) held in the loading station:

-a manipulator (35) for handing a new ladle shroud (13b) to a ladle located at said loading station, and

-coupling a drive means (17) to the ladle slide gate mechanism (15),

each robot is fixed with respect to the respective first or second ladle (11, 12) so as to move between the loading station and the casting station together with the respective first or second ladle.

2. Metal casting plant according to claim 1, wherein the loading platform (20) comprises a tool storage rack (29) containing one or more spare ladle shroud (13b, 13c) within reach of the robot (21) and preferably comprising tools and/or one or more drive means (17) and/or a spare downcomer (14).

3. A metal casting plant according to claim 2, wherein the robot (21) is movably mounted on the loading platform (20) so that it can translate parallel to a first axis (X) and/or a second axis (Y) perpendicular to the first axis (X), or a combination thereof, and/or rotate about a vertical axis (Z) perpendicular to the first and second axes (X, Y) in order to reach the storage rack (29) and retrieve any tools or components from the storage rack (29) and reach the ladle slide gate mechanism of the first or second ladle (11, 12) held at the loading station, to perform the operation defined in claim 1.

4. Metal casting installation according to any of the preceding claims, wherein the robot (21) is configured for

-collecting the ladle shroud (13a-13c) from a robot (35) holding the emptied first or second ladle (11, 12) at the loading station after movement from the casting station, and

-removing the drive means (17).

5. Metal casting apparatus according to any of the preceding claims, wherein the ladle sliding gate valve mechanism (15) comprises:

(a) an upper plate (15u) comprising:

a fixed surface and a bottom sliding surface, said fixed surface and said bottom sliding surface being spaced apart from each other by the thickness of said upper plate;

an upper aperture extending from the fixed surface to the bottom sliding surface, and wherein

-the fixing surface of the upper plate is rigidly fixed to a lower portion of the respective first or second ladle (11, 12), wherein the upper aperture is in fluid communication with the opening,

(b) a lower plate (15d) comprising:

a nozzle surface and a top sliding surface, the nozzle surface and the top sliding surface being spaced apart from each other by the thickness of the lower plate;

a lower bore extending from the top sliding surface to the gate surface, wherein

-the lower plate (15d) is slidably mounted such that the top sliding surface is translationally slidable along the bottom sliding surface to bring the lower aperture into and out of fluid communication with the upper aperture, and wherein

(c) The lower nozzle (14) comprising a lower nozzle hole and being fixed to a nozzle surface of the lower plate (15d), wherein the lower nozzle hole is in fluid communication with the lower hole,

(d) the drive means (17) are coupled to the lower plate (15d) and comprise a cylinder (17c) rigidly and reversibly coupled to a bottom portion of the respective first or second ladle (11, 12) and a piston (17p) rigidly and reversibly fixed to the lower plate (15d), the drive means being configured for moving the lower plate to align or misalign the lower and upper apertures.

6. The metal casting apparatus of claim 5,

the lower plate (15d) comprises a second lower hole, separate from the lower hole and extending from the top sliding surface to the gate surface, and

-a second lower nozzle (14) comprising a second lower nozzle hole is fixed to the nozzle surface of the lower plate (15d), wherein the second lower nozzle hole is in fluid communication with the second lower hole.

7. Metal casting installation according to any of the preceding claims, wherein each of the first and second manipulators (35) is provided with a corresponding tool

Fixed to respective first and second holding devices, or

Ladle slide gate mechanisms (15) fixed to the respective first and second ladles so as to move together with said lower plate, or

Fixed to the respective first and second ladles (11, 12).

8. Metal casting installation according to any of the preceding claims, wherein each of the first and second manipulators (35) is provided with a corresponding tool

Can translate along a first direction parallel to the upper hole,

-being able to rotate around said first direction,

comprising one or more arm sections extending substantially perpendicular to a column parallel to the first direction, the one or more arm sections being coupled to the column and to each other by a rotational joint configured for rotation about the first direction,

-comprising clamping means at the free end of the arm section furthest from the column for firmly and reversibly holding the ladle shroud (13a-13 c).

9. Metal casting apparatus according to any of the preceding claims, wherein the driving means (17) is actuated hydraulically or pneumatically or electrically, and wherein each of at least the first and second holding means of the transporting means is provided with:

a source of pressurized fluid, or electric power, for actuating the drive means (17) via a hose (17t), and

a preferred storage station for storing a drive device (17) ready to be coupled to a ladle slide gate mechanism.

10. A metal casting apparatus as claimed in any preceding claim, including a preheat bake oven (25) for bringing and maintaining a new ladle shroud (13b) loaded onto the ladle slide gate mechanism (15) of the first or second ladle (12) at the loading station to and at a preheat temperature.

11. The metal casting apparatus of any preceding claim, wherein the robot is further configured to:

-checking the status of a used ladle shroud (13a-13c) after it has been removed from the emptied ladle,

-assessing whether the used ladle shroud can be reused after cleaning or must be discarded, and

cleaning the used ladle shroud with an oxygen blower to remove any residue adhering to the walls of the used ladle shroud.

12. A method for casting molten metal comprising the steps of:

(a) providing a metal casting apparatus according to any of the preceding claims,

the first ladle is filled with molten metal (2) and is in the casting station, and

the second ladle (12) is filled with molten metal (2) and is in the loading station,

-the ladle sliding nozzle mechanism (15) of said first ladle (11) is in said sealing position, coupled with one or more drive means (17) and provided with ladle longnozzles (13a-13c) held on the collector nozzle (14) by respective manipulators,

-the ladle slide gate mechanism (15) of the second ladle (12) is in the sealing position and comprises a collector nozzle (14) fixed to the lower plate (15d), but not comprising ladle shroud (13a-13c) and operable drive means (17),

(b) bringing a ladle slide gate mechanism (15) of said first ladle (11) into a casting position for casting molten metal from said first ladle (11) through said ladle shroud (13a) into said tundish (1),

(c) during the course of the preceding step(s),

-a second manipulator for transferring the new ladle shroud (13b) to the second ladle (12) by means of the robot (21),

-coupling the new ladle shroud (13b) with the second robot (35) and holding it in position on the collector nozzle (14) with the second robot,

-coupling the drive means (17) to a sliding gate valve mechanism (15) of the second ladle (12) with the robot (21),

(d) bringing a ladle slide gate mechanism (15) of said first ladle (11) into said sealing position when said first ladle is substantially empty, and then

(e) Exchanging the positions of the first ladle and the second ladle by moving the first ladle (11) from the casting station to the loading station and concomitantly moving the second ladle (12) from the loading station to the casting station,

(f) bringing a ladle slide gate nozzle mechanism (15) of the second ladle (12) into a casting position and casting molten metal from the second ladle (12) through the ladle shroud (13b) into the tundish (1).

13. The method of claim 12, comprising the steps during step (f):

(g) withdrawing the used ladle shroud (13a) from the delivery nozzle (14) with the first robot (35),

(h) collecting the used ladle shroud (13a) from the first manipulator (35) with the robot (21) and storing it for hot repair or as waste, and

(i) decoupling and removing the one or more drive devices (17) from the sliding gate valve mechanism (15) of the first ladle (11) with the robot (21) and storing the one or more drive devices for further use,

(j) removing the emptied first ladle (11), and

(k) loading a new ladle filled with molten metal onto the first holding means of the transporting means at the loading station, wherein the new ladle comprises a ladle slide gate mechanism (15) fixed with a collector nozzle (14) in the sealed position, like the second ladle (12) in step (a), but the new ladle does not comprise ladle shroud nozzles (13a-13 c).

14. A method according to claim 11 or 12, wherein the opening of the first ladle is filled with a plugging material (19) and if in step (b) no or little molten metal flows out of the opening when the ladle slide gate valve mechanism (15) of the first ladle (11) is brought into the casting station, the following steps are performed:

withdrawing the ladle shroud (13a) from the collector nozzle (14) with the first robot (35) to expose the collector nozzle,

-dredging the opening of the first ladle by breaking the plugging material through this exposed drain opening (14) with a suitable dredging tool (19r),

-when the plugging material starts to flow out of the collector nozzle, coupling the ladle shroud (13a) with the first manipulator (35) and holding it in place on the collector nozzle (14) with the first manipulator and thus allowing the molten metal to be cast from the first ladle (11) through this unplugged opening and through the ladle shroud (13a) into the tundish (1).

15. The method according to claim 11 or 12, wherein the lower plate (15d) comprises a first and a second lower hole and a first and a second lower nozzle as defined in claim 6, wherein the opening of the first ladle is filled with a plugging material (19), and if in step (b) the ladle sliding gate valve mechanism (15) of the first ladle (11) is brought into the casting station with no or little molten metal flowing out of the opening, wherein the first lower hole is aligned with the upper hole, the following steps are performed:

-translating the lower plate (15d) with the driving means (17) to a dredging position in which the second lower holes are aligned with the upper holes,

-dredging the opening of the first ladle by breaking the plugging material through the thus exposed second drain opening (14) with a suitable dredging tool (19r),

-when the plugging material starts to flow out of the lower nozzle, translating the lower plate (15d) with the drive means (17) back to the casting position in which the first lower hole is aligned with the upper hole and thus allowing the molten metal to be cast from the first ladle (11) through this unplugged opening and through the ladle shroud (13a) into the tundish (1).

16. The method of any one of claims 11 to 13, wherein the transport device is a turntable (30), and wherein the step (e) of exchanging the positions of the first ladle and the second ladle comprises the steps of:

-lifting the first and second ladles (11, 12) until the ladle longnozzles (13a, 13b) of the first and second ladles are both free of the tundish and are higher than the tundish in the vertical direction (Z),

-rotating the turret by 180 DEG about the vertical axis (Z) so that the first ladle (11) is higher than the loading station and the second ladle (12) is higher than the casting station and higher than the tundish (1),

-lowering the first and second ladles (11, 12) to their respective loading and casting stations, the ladle shroud (13b) of the second ladle being inserted into the tundish (1),

wherein during all previous steps the first and second robots (35) move together with the respective first and second ladles (11, 12) while holding the respective ladle shroud (13a-13c) on the respective collector nozzle (14).

17. The method of any of claims 12 to 16, wherein the robot further:

-checking the status of a used ladle shroud (13a-13c) after it has been removed from the emptied ladle,

-assessing whether the used ladle shroud can be reused after cleaning or must be discarded, and

cleaning the used ladle shroud with an oxygen blower to remove any residue adhering to the walls of the used ladle shroud.

Technical Field

The present invention relates to a robotic loading station for preparing fresh ladles loaded on a rotating turret prior to loading the fresh ladles into a casting station above a tundish. In particular, the present invention relates to a ladle sliding gate mechanism (sliding gate) for loading a ladle shroud into coupling with an outlet of a ladle, and a robotic apparatus for coupling a drive device to both the ladle and the ladle sliding gate mechanism to actuate the ladle sliding gate mechanism. The robotic loading station is further configured for decoupling the drive means and unloading the used ladle shroud from an empty ladle that was most recently removed from the casting station above the tundish. The robotisation of these operations frees the operator from heavy work and improves the repeatability of the operations. The particular manipulator embedded in the respective ladle and ladle slide gate mechanism allows to rapidly unblock the outlet when it becomes blocked.

Background

In a continuous metal forming process, a metal melt (2) is transferred from one metallurgical vessel to another, to a mould or a crystallizer. For example, as shown in fig. 1, ladles (11, 12) are filled with a metal melt from a furnace (not shown) and transferred over a tundish (1) to discharge molten metal from the ladles through ladle shroud openings (13a-13c) into the tundish. The metal melt can then be cast from a tundish through a pouring nozzle (3) into a mould or a crystallizer to continuously form slabs, billets, beams, thin slabs and the like. Under the action of gravity, the metal melt flows out of the ladle into the tundish and then flows out of the tundish into the mold or crystallizer. The flow rate may be controlled by a sliding gate valve mechanism in fluid communication with the outlet of the ladle and the tundish. The ladle slide gate valve mechanism (15) can be used to control the flow rate out of the ladle and even to interrupt the flow at the sealing location. Similarly, a tundish sliding gate valve mechanism (5) may be used to control the flow rate out of the tundish and to interrupt the flow in the sealing position.

Since the casting of the metal into the mould or crystalliser is carried out continuously, the tundish acts as a buffer and the level of molten metal in the tundish must remain substantially constant throughout the casting operation. Maintaining the level of molten metal in the tundish substantially constant requires a quick exchange of the new ladle, filled with molten metal, with the old ladle after it has been emptied, to ensure quasi-continuous feeding of molten metal to the tundish, so that the metal is poured into the tundish at substantially the same rate as it flows out into the mould or crystalliser. This operation becomes more complicated due to the following constraints.

Firstly, ladles (11, 12) cannot be transported from the furnace to the respective tundish above the plant for safety reasons and to avoid any collision, wherein ladle shroud (13a-13c) is coupled to and extends 1m or more below the bottom floor of the ladle, which must be coupled to the bottom floor of the ladle at a loading station close to the tundish.

Secondly, in order to prevent the metal contained in the second ladle (12) from freezing in contact with the "cold" moving parts of the ladle slide gate valve mechanism (15) held in a sealed position, thereby avoiding clamping of the mechanism and preventing the ladle slide gate valve mechanism from opening, the inner bore of the inner gate is typically filled with a plug material (19), typically sand or other particulate material, to prevent any metal melt from reaching the gate mechanism, thereby preventing metal freezing and clogging of the inner gate and gate mechanism system. With the ladle at the casting station, after the ladle slide gate mechanism is opened to the casting position, sand flows out and then molten metal can flow into the tundish through the ladle shroud. However, sometimes the plugging material can locally bond with the frozen metal to form a solid plug, thereby preventing the plugging material from flowing out. Therefore, the inner nozzle is blocked, and metal cannot flow out of the ladle into the tundish despite the ladle slide gate mechanism being in the casting position. This problem can be easily solved by inserting a pull through (19r) into or close to the bore of the inner nozzle. The pull throughs (19r) can be pressurized gas spray guns or elongated rods, as illustrated in fig. 2 (c). Now, this seemingly simple operation is in fact quite complicated due to the long ladle shroud (13a-13c) coupled with the ladle slide gate mechanism.

For these reasons, in most installations, the ladle shroud is not coupled to the sliding nozzle mechanism in an autonomous manner at the loading station, but rather the ladle shroud is inserted onto the downcomer and held in place by a robot located at the casting station. This allows the ladle shroud to be removed from the collector nozzle by a robot in the event of ladle outlet blockage, so that the ladle outlet is more easily accessible from the bottom with a pull through tool (19 r). Once the blocked channel is unblocked, the ladle slide gate mechanism can be moved to the sealing position while the robot reintroduces the ladle shroud onto the collector nozzle. At this time, the ladle slide gate valve mechanism moves back to the casting position to start casting the molten metal into the tundish. However, robots are not always available or even capable of being placed on a casting platform at a casting station, which may be small and crowded. Under such conditions, this solution of holding the ladle shroud during the casting process becomes problematic.

The recently filled ladle is transported from the furnace to the casting apparatus where the ladle slide gate mechanism is fixed to the bottom floor of the ladle but there is no drive means to actuate the relative movement of the plates forming the ladle slide gate mechanism. To this end, many metallurgical plants use a rotary table (30) comprising first holding means for holding a first ladle (11) at a casting station above a tundish (1), and second holding means for holding a second ladle (12) filled with molten metal at a loading station. While the first ladle is discharging the molten metal contained therein into the tundish, the second ladle may be prepared to perform the same operation once the first ladle is emptied. In particular, a drive means such as a hydraulic piston may be coupled to the bottom floor of the ladle and the ladle slide gate mechanism to allow actuation thereof.

US 2006/0118268 describes a ladle sliding gate nozzle mechanism configured to autonomously hold ladle longnozzles and a collector nozzle arranged side by side. One or more drive devices (e.g., hydraulic pistons, etc.) may be used to actuate the ladle sliding gate mechanism by moving a plate of the ladle sliding gate mechanism between a sealing position in which the opening is sealed, a casting position in which the opening is in fluid communication with the ladle shroud, and a deoccluding position in which the opening is in fluid communication with the downcomer. In this way, in the event of bore blockage, the ladle slide gate mechanism is moved to the dredging position, so that the dredging tool (19r) can be easily introduced through the short lower gate hole to break the plugging material with the solidified metal incorporated therein. Once the plugging material is again flowable, the ladle slide gate mechanism moves the collector nozzle into alignment with the ladle outlet and brings the ladle shroud into the casting position to allow molten metal to flow through the ladle shroud into the tundish. The handling of the pull through tool (19r) can advantageously be performed by a robot located in the vicinity of the casting station. Compared to the above described holding of a ladle shroud by a robot, a significant advantage is that with this ladle sliding gate mechanism, no robot is required to hold the ladle shroud and, instead, a robot can be used to operate the dredging tool (19 r). Otherwise, this operation must be performed manually by a human operator, or a second robot must be installed near the casting station to unblock the internal bore. Manual handling is generally more laborious and takes longer than a robot performing this operation. This is disadvantageous because the longer the ladle does not supply fresh molten metal to the tundish, the lower the level of molten metal in the tundish and/or the longer the casting operation has to be carried out at a lower flow rate, which can deteriorate the quality of the cast slab thus produced.

US 2008/0314938 describes a continuous casting plant with at least one multi-function robot for carrying out a plurality of different process-controlled or automated interventions in the continuous casting plant. A multi-function robot arranged on a pivotable arm at a rotating column, which is fastened to a casting platform of a continuous casting plant, can be pivoted between a retracted position and an operating position by means of the pivotable arm. The robot may also move relative to its arm.

The operation of rapidly exchanging the emptied first ladle with the filled second ladle at the casting station remains a delicate operation. In the event of a blockage of the internal bore, this operation becomes more critical, which may increase the time during which the tundish is not replenished with fresh molten metal. In the metal casting industry, there is a need for ladle exchange operations that are repeatable and in less time. The invention proposes a metal casting plant with a fully automatic ladle change operation, including in the event of the ladle outlet being blocked by frozen plugging material (19), allowing a repeatable and in all cases shorter exchange operation. These and other advantages of the present invention will be described in more detail in the sections that follow.

Disclosure of Invention

The object of the present invention has been achieved by a metal casting apparatus comprising:

(a) a loading platform is arranged on the base plate,

(b) the middle bag is a bag-shaped bag,

(c) a first ladle and a second ladle, each of the first ladle and the second ladle comprising:

a bottom plate provided with an opening,

the long nozzle of the ladle,

a ladle sliding gate valve mechanism comprising a drain valve configured for reversibly receiving and supporting a ladle shroud, the ladle sliding gate valve mechanism further configured for coupling with a drive arrangement for actuating the ladle sliding gate valve mechanism between a sealing position in which the opening is sealed and a casting position in which the opening is in fluid communication with the ladle shroud,

(d) the first ladle long nozzle manipulator and the second ladle long nozzle manipulator are respectively used for fixing the connected ladle long nozzles on the lower nozzles of the first ladle and the second ladle,

(e) a transport device comprising a turntable or ladle carriage, the transport device comprising at least a first holding device and a second holding device for holding a first ladle and a second ladle, respectively, wherein the transport device is configured for moving and holding in place the first ladle and the second ladle between a loading station adjacent to the loading platform and a casting station above the tundish,

wherein the content of the first and second substances,

the metal casting plant comprises a robot configured for performing the following operations on the first ladle or the second ladle held in the loading station:

a manipulator for transferring the new ladle shroud to the ladle at the loading station, and

coupling the drive means to the ladle slide gate mechanism,

each robot is fixed with respect to the respective first or second ladle so as to move between the loading station and the casting station together with the respective first or second ladle.

The loading platform may comprise a tool storage rack containing one or more spare ladle shroud within reach of the robot, and preferably comprising one or more drive means and/or spare parts such as spare downcomers, and tools. The robot may be movably mounted on the loading platform such that the robot may translate parallel to the first axis (X) and/or the second axis (Y) perpendicular to the first axis (X), or a combination thereof, and/or rotate about a vertical axis (Z) perpendicular to the first axis and the second axis (X, Y). Preferably, the robot can thus reach the storage rack and retrieve any tools or components from the storage rack, and can reach the ladle slide gate mechanism of the first ladle or the second ladle held at the loading station, in order to perform the above-described operations.

Preferably, the robot is configured for:

collecting the ladle shroud from a robot holding the emptied first or second ladle at the loading station after movement from the casting station, and

remove the drive.

The ladle sliding gate valve mechanism may include:

(a) an upper plate, the upper plate comprising:

a fixed surface and a bottom sliding surface, the fixed surface and the bottom sliding surface being spaced from each other by the thickness of the upper plate;

an upper aperture extending from the fixed surface to the bottom sliding surface, and wherein

The fixing surface of the upper plate is rigidly fixed to the lower portion of the respective first ladle or second ladle, wherein the upper aperture is in fluid communication with the opening,

(b) a lower plate, the lower plate comprising:

a nozzle surface and a top sliding surface, the nozzle surface and the top sliding surface being spaced apart from each other by the thickness of the lower plate;

a lower bore extending from the top sliding surface to the nozzle surface, wherein

The lower plate is slidably mounted such that the top sliding surface is translationally slidable along the bottom sliding surface to bring the lower aperture into and out of fluid communication with the upper aperture, and wherein

(c) The drain comprises a drain hole and is fixed to the drain surface of the lower plate, wherein the drain hole is in fluid communication with the drain hole,

(d) a drive device is coupled to the lower plate and includes a cylinder rigidly and reversibly coupled to a bottom portion of the respective first ladle or second ladle and a piston rigidly and reversibly fixed to the lower plate, the drive device being configured for moving the lower plate to align or misalign the lower aperture with the upper aperture.

In a first embodiment, the lower plate comprises a single lower hole, wherein a single lower nozzle is fixed to the nozzle surface of the lower plate.

In the second embodiment of the present invention,

the lower plate comprises a second lower hole, separate from the lower hole and extending from the top sliding surface to the nozzle surface, and

a second drain port comprising a second drain port hole is fixed to the surface of the lower plate, wherein the second drain port hole is in fluid communication with the second drain hole.

Each of the first and second manipulators may

Fixed to respective first and second holding devices, or

Ladle slide gate mechanisms fixed to the respective first and second ladles so as to move together with the lower plate, or

Fixed to the respective first and second ladles.

Preferably, each of the first robot arm and the second robot arm

Capable of translation along a first direction parallel to the upper hole,

is capable of rotating in a first direction,

comprising one or more arm sections extending substantially perpendicular to a column parallel to the first direction, the one or more arm sections being coupled to the column and to each other by means of rotary joints configured for rotation about the first direction,

comprises a clamping device located at the free end of the arm section furthest from the column for firmly and reversibly holding the ladle shroud.

The drive means may be actuated hydraulically or pneumatically or electrically. Preferably, each of the first holding device and the second holding device of the transport device is provided with:

a source of pressurized fluid, or electric power, for actuating the drive device via a hose, and

a preferred storage station for storing a drive device ready to be coupled to a ladle slide gate mechanism.

The metal casting apparatus may include a preheat bake-out oven for bringing and maintaining a new ladle shroud loaded on a ladle slide gate nozzle mechanism of a first ladle or a second ladle at a loading station to and at a preheat temperature.

In a preferred embodiment, the robot may be further configured to:

checking the condition of the used ladle shroud after it has been removed from the emptied ladle,

assessing whether the used ladle shroud can be reused after cleaning or must be discarded, and

the used ladle shroud is cleaned with an oxygen blower to remove any residue adhering to the walls of the used ladle shroud.

The invention also relates to a method for casting molten metal, comprising the steps of:

(a) there is provided a metal casting apparatus as hereinbefore described, wherein,

the first ladle is filled with molten metal and is in the casting station, and

the second ladle is filled with molten metal and is in the loading station,

the ladle slide gate mechanism of the first ladle is in this sealing position, coupled with one or more drive means and provided with a ladle shroud, held on the collector nozzle by a respective manipulator,

the ladle slide gate mechanism of the second ladle is in this sealing position and comprises a collector nozzle fixed to the lower plate, but not a ladle shroud and an operable drive means,

(b) bringing the ladle slide gate nozzle mechanism of the first ladle into a casting position to cast the molten metal from the first ladle through the ladle long gate nozzle into the tundish,

(c) during the course of the preceding step(s),

a second manipulator for moving the new ladle shroud to the second ladle by the robot,

coupling the new ladle shroud with a second robot and holding the new ladle shroud in position on the collector nozzle with the second robot,

robotically coupling the drive to the sliding gate mechanism of the second ladle,

(d) when the first ladle is basically empty, the ladle sliding nozzle mechanism of the first ladle is enabled to enter the sealing position, and then

(e) Exchanging the positions of the first ladle and the second ladle by moving the first ladle from the casting station to the loading station and concomitantly moving the second ladle from the loading station to the casting station,

(f) the ladle slide gate mechanism of the second ladle is brought into a casting position and molten metal is cast from the second ladle through the ladle shroud into the tundish.

During step (f), the method preferably comprises the steps of:

(g) withdrawing the used ladle shroud from the downcomer by the first manipulator (35),

(h) collecting the used ladle shroud from the first robot with the robot and storing the used ladle shroud for hot repair or as waste, and

(i) decoupling and removing the one or more drive devices (17) from the sliding gate valve mechanism of the first ladle with the robot and storing the one or more drive devices for further use,

(j) removing the emptied first ladle, and

(k) loading a new ladle filled with molten metal onto the first holding means of the transporting means at a loading station, wherein the new ladle comprises the ladle slide gate mechanism with the fixed collector nozzle in a sealed position but does not comprise the ladle shroud, like the second ladle in step (a).

If the opening of the first ladle is filled with the plugging material and if no molten metal flows out of the opening when the ladle slide gate valve mechanism of the first ladle is brought into the casting station in step (b), the unblocking of the opening may be performed in different ways.

In a first method, the following steps may be performed:

withdrawing the ladle shroud from the downcomer with the first robot to expose the downcomer,

unblocking the opening of the first ladle by breaking the plugging material through this exposed drain opening with a suitable unblocking tool,

when the plugging material starts to flow out of the collector nozzle, the ladle shroud is coupled with and held in place on the collector nozzle with the first manipulator and molten metal is thus allowed to be cast from the first ladle through this unplugged opening and through the ladle shroud into the tundish.

In a second method, wherein the lower plate comprises the first and second lower holes and the first and second lower nozzles as described above in relation to the second embodiment, the following steps may be performed:

translating the lower plate with the drive means to a second dredging position in which the lower aperture is aligned with the upper aperture,

unblocking the opening of the first ladle by breaking the plugging material through this exposed second drain opening with a suitable unblocking tool,

when the plugging material starts to flow out of the lower nozzle, the lower plate is translated with the drive means back to the casting position in which the first lower hole is aligned with the upper hole, and thus allows the molten metal to be cast from the first ladle through this unplugged opening and through the ladle shroud into the tundish.

The transport device may be a turntable. The step (e) of exchanging the positions of the first ladle and the second ladle may thus comprise the steps of:

lifting the first ladle and the second ladle until the ladle shroud of the first ladle and the second ladle are both detached from the tundish and are higher than the tundish in the vertical direction (Z),

-rotating the turret by 180 DEG about the vertical axis (Z) so that the first ladle is higher than the loading station and the second ladle is higher than the casting station and higher than the tundish,

lowering the first ladle and the second ladle to their respective loading and casting stations, the ladle shroud of the second ladle being inserted into the tundish,

wherein during all preceding steps the first and second robots (35) move together with the respective first and second ladle while holding the respective ladle shroud on the respective collector nozzle.

In a further embodiment, the robot further:

checking the condition of the used ladle shroud after it has been removed from the emptied ladle,

assessing whether the used ladle shroud can be reused after cleaning or must be discarded, and

the used ladle shroud is cleaned with an oxygen blower to remove any residue adhering to the walls of the used ladle shroud.

Drawings

In the context of the drawings, it is,

fig. 1(a) - (f) depict various steps of swapping an emptied first ladle out of a casting station and replacing the first ladle with a second ladle after a full second ladle is ready at a loading station.

Fig. 2(a) - (d) show various steps for dredging a blocked ladle outlet using a ladle sliding gate mechanism according to a first embodiment of the present invention.

Fig. 3(a) - (d) show various steps for dredging a blocked ladle outlet using a ladle sliding gate mechanism according to a second embodiment of the present invention.

Fig. 4(a) - (c) show various alternative steps for dredging a blocked ladle outlet using a ladle sliding gate valve mechanism according to a first embodiment of the present invention.

Fig. 5(a) - (c) show various steps of loading a new ladle shroud onto a collector nozzle using a robot according to an embodiment of the present invention.

Fig. 6 shows a loading station comprising a robot, and a full ladle supported by a robot-equipped transport device according to an embodiment of the invention.

Detailed Description

As illustrated in fig. 1, the metal casting apparatus according to the present invention includes a first ladle (11) and a second ladle (12). The first ladle is held at a casting station above the tundish (1) for transferring the molten metal (2) contained in the first ladle (11) into the tundish (1). The tundish delivers the molten metal to the mould or die. By this system, the tundish contains a volume of molten metal which remains substantially constant throughout the transfer of molten metal from the first ladle (11) to the tundish (1). When the first ladle has been emptied of its contents, it must be replaced as quickly as possible with a second ladle (12) filled with molten metal and sufficiently prepared to continue the transfer of molten metal (2) to the tundish (1) so as to keep the level of molten metal in the tundish substantially constant, while keeping the flow rate of molten metal from the tundish into the mould or die substantially constant.

The ladles (11, 12) include a floor provided with openings (11o, 12 o). An inner nozzle (18) provided with an inner bore fluidly communicates the inner volume of the tundish with the openings (11o, 12 o). The ladle (11, 12) further comprises a ladle sliding gate valve mechanism (15) configured for reversibly receiving and supporting a drain valve aligned with the lower bore, and for coupling with a drive arrangement (17) for actuating the ladle sliding gate valve mechanism between a sealing position in which the opening is sealed from the drain valve and a casting position in which the opening is in fluid communication with the drain valve and the ladle shroud (13a-13 c). The ladle shroud is coupled to the collector nozzle by a robot (35) and is thus maintained in position.

In order to accelerate the exchange between the emptied first ladle (11) and the filled second ladle (12), the first ladle and the second ladle are supported by respective first and second holding means of the transport device. The transport means may be a buggy ladle, but is preferably a rotating turntable (30) (see fig. 1 (a)). The first and second holding means are fork arms which hold the first and second ladles (11, 12) at an "arm length" from the central axis of rotation (Z). Rotation of the turret about a central axis of rotation (Z) allows the first ladle and the second ladle to move between:

a casting station, wherein one of the first or second ladles (11, 12) is held above a tundish, the ladle shroud (13a-13c) is partially inserted into the tundish, and

a loading station where the other of the first ladle or the second ladle is ready to transfer molten metal into the tundish as it moves into the casting station.

Since the ladle shroud (13a-13c) is partially inserted into the tundish (1), the turret (30) must first lift the first and second ladles to drive the ladle shroud (13a) of the first ladle (11) away from the tundish (1) and over the tundish (1) before rotating about the central axis of rotation (Z) to avoid collision of the ladle shrouds of the first and second ladles with the tundish.

The loading station is provided with a loading platform (20) comprising tools and spare parts, such as new ladle shroud (13b, 13c), new downcomer (14), or spare drive means (17). As explained above, the ladle cannot be transported between the furnace and the casting equipment across the plant because the long ladle nozzles (13a-13c) protrude from the bottom floor of the ladle. Thus, a fresh ladle filled with molten metal arrives at the casting station without ladle shroud (13a-13 c). A fresh ladle (11, 12) filled with molten metal (2) arrives at a turret (30) with a ladle slide gate mechanism (15) fixed to the bottom floor of the ladle, but without an operable drive (17), and a downcomer (14) coupled to the ladle slide gate mechanism. The down nozzle is very short and can be attached to a ladle travelling across the plant without any risk of collision. Thus, when a fresh ladle (12) is docked on the turret (30) at the loading station, a new ladle shroud (13a-13c) can be coupled to the fresh ladle above the downcomer (14) and maintained in position. At the same time, the drive means (17) must be coupled to the ladle (11, 12) and the ladle slide gate mechanism (15), and the drive means (17) must be activated by a source of pressurized fluid connecting it to the hydraulic or pneumatic drive means (17) or a source of electric power for the electric drive means (17).

The invention proposes to provide a robot (21) on or near the loading platform (20), instead of these operations being performed manually by a human operator. A robot (21) is configured for loading a new ladle shroud (13b) onto the ladle slide gate valve mechanism (15) and for coupling the drive means (17) to the ladle slide gate valve mechanism (15).

Casting equipment

Figure 1 shows the various steps of a continuous casting operation using the apparatus according to the invention. The exchange of an emptied first ladle (11) with a filled second ladle (12) will be discussed in more detail in the following sections. Fig. 1(a) shows a turntable (30) as a transport means, the turntable comprising first and second holding means for holding first and second ladles (11, 12). The turret is located in the vicinity of the tundish so that each of the first and second holding devices can bring the ladle (11, 12) to a casting station, in which the ladle shroud is partially inserted in the tundish below the level of the molten metal contained in the tundish during use in stable conditions. Fig. 1(a) shows a configuration in which a first ladle (11) is partially filled with molten metal, held at a casting station by first holding means of a turret (30). A first ladle is above the tundish (1), wherein the ladle shroud (13a-13c) is held in position by a ladle shroud robot (35) fixed to a first holding means of the turret (30) such that the ladle shroud is partially inserted into the tundish and partially submerged below the level of molten metal contained in the tundish. The ladle slide gate valve mechanism (15) of the first ladle (11) is coupled to a drive arrangement (17) configured to move the plate of the slide gate valve mechanism between the sealing position and the casting position as described above. In the embodiment of fig. 1, the drive means (17) is a hydraulic piston which is connected to a source of pressurized fluid (17h) by a hose (17 t). The drive means (17) may be pneumatic or electric, but hydraulic drive means are preferred.

A second ladle (12) filled with molten metal coming directly from the furnace is held by the second holding means of the turret (30) at the loading station and within the robot reach of the loading platform (20) at the loading station. The ladle sliding nozzle mechanism (15) of the second ladle (12) is in a sealing position. Unlike the first ladle (11), the second ladle (12) is not ready for casting molten metal, since it does not have any ladle shroud (13b) and any drive means (17). It is possible to have the second ladle (12) already equipped with a drive means (17), but which is not in operation, since it is not connected to any source of pressurized fluid for the hydraulic and pneumatic drive means, nor to the electric power source for the electric drive means. Typically, the second ladle (12) arrives at the turntable without any drive means (17), and in a few cases is provided with drive means that are not operable.

The loading platform (20) comprises a storage rack (29) with the various tools (not shown) required for preparing the second ladle (12) for casting, and with spare ladle shroud (13b, 13 c). Preferably, the ladle shroud (13a-13c) arranged in the first for coupling with the ladle is preheated in a storage rack (29) or in a separate baking oven within reach of the robot, in order to avoid any severe thermal shock when the molten metal flows through the ladle shroud after the start of the casting operation at the casting station. In some cases, the platform may include a backup drive (17), and possibly a backup drain (14), although the drain (14) is preferably coupled to a second ladle in a separate hot repair station prior to filling the ladle with molten metal in the furnace.

Preferably, the drive means (17) for actuating the ladle slide gate mechanism (15) of the second ladle (12) is stored on or near the second holding means of the turret (30). It is preferred to store the drive means on the first and second holding means, because in this way it is not necessary to connect and disconnect the (drawer) drive means each time it is coupled to or removed from the ladle, because it is most convenient to position the source of pressurised fluid (17h) on or near the first and second holding means as well, as shown in fig. 1 (a).

Fig. 1(b) shows that when a first ladle (11) discharges its molten metal content into a tundish, the robot (21) removes a new ladle shroud (13b) from the storage rack (29) and couples the new ladle shroud to the ladle slide gate mechanism (15) of a second ladle (12), which is held in a sealed position throughout the residence time of the second ladle at the loading station. As explained above, in the preferred embodiment, the new ladle shroud (13b) is heated to a pre-heat temperature in the storage rack 29 or in a separate oven within reach of the robot (21) before being loaded onto the ladle slide gate mechanism. Preheating the ladle shroud prior to casting reduces the risk of cracking due to severe thermal shock, since the molten metal does not begin to flow through the ladle shroud at the start of the casting operation. Since the second ladle (12) provided with the new ladle shroud (13b) can remain in the loading station for a certain time before being moved to the casting station, the new ladle shroud (13b) has time to cool down, losing all the benefits of the preheating operation, because the first ladle (11) is transferring molten metal to the tundish and is gradually emptied. To this end, in a preferred embodiment of the invention illustrated in fig. 1(c), in addition to or instead of preheating the new ladle shroud in a storage rack or a separate baking oven, a preheat bake oven (25) may be provided at the loading station for (optionally reaching and) maintaining the new ladle shroud (13b) held by the robot above the downcomer (14) of the ladle slide shroud mechanism (15) of the second ladle (12) at the loading station at a preheat temperature. By means of this preheating bake-out oven (25), the ladle shroud reaches the casting station at the required preheating temperature and casting can be started with a low risk of cracking due to thermal shock. The preheat bake oven (25) may be movably coupled to the loading platform (20), or to the first and second holding devices of the turntable. The pre-heating bake oven is preferably in the form of an open book that surrounds the new ladle shroud (13b) once it has been loaded onto the ladle slide gate mechanism (15). The robot (21) can carry the oven into a preheating position.

The robot (21) is preferably movable in a horizontal plane (X, Y) and has several degrees of freedom, preferably at least five or at least seven degrees of freedom. The robot must be able to reach the storage rack (29) to collect or store the tools and/or casting components, and must also be able to reach the ladle shroud robot (35) of the ladle staying at the loading station. The robot must have sufficient degrees of freedom to perform all the connections and disconnections and couplings and disconnections necessary to ensure the continuous casting operation of the casting apparatus.

In particular, as shown in fig. 1(b) and 1(c), the robot must be configured for handling a new ladle shroud (13b) to the manipulator (35) and for recovering a used ladle shroud from an empty ladle exiting the manipulator (35). The robot must also be configured for coupling (disconnecting) the drive means (17) with the ladle slide gate mechanism (15) and the ladle, and for coupling (disconnecting) the hose (17t) with the drive means (17). In fig. 1, the first holding device and the second holding device of the turn table (30) are each provided with:

a storage station for storing one or more (drawer) drives (17), and

a source of pressurized fluid connected to the one or more (drawer) drives for actuating the ladle slide gate mechanism (15).

With this arrangement all the robot (21) needs to do is to collect the drive means (17) from its storage station at the second holding means and couple it to the ladle and the ladle slide gate mechanism (15). If the drive means are stored in a storage rack (29), or if the drive means stored in the storage station have to be replaced by new drive means stored in the storage rack (29), the robot (21) has to couple one or more hoses (17t) to the respective (drawer) drive means in addition to coupling one or more (drawer) drive means (17) to the ladle and ladle slide gate mechanism (15) in order for the drive means to operate to actuate the ladle slide gate mechanism.

Because the ladles (11, 12) are supported by a transport means such as a turret (30) or ladle car, the ladle is followed by a ladle shroud robot (35) (or simply "robot") during all operations of the ladle. In a first embodiment, as illustrated in fig. 1 and 3, the robot may be fixed to the first and second holding devices of the transport device. This solution is advantageous because the manipulator remains coupled to the transport means for the complete duration of one or more casting operations and must not be changed each time a new ladle reaches the transport means. Alternatively, according to the second embodiment, the robot arm may be fixed to the ladle sliding gate mechanism (15), preferably moving together with the lower plate (15d), as illustrated in fig. 2(a) to 2 (d). This solution does not have the advantages of the previous embodiment, but has the following advantages, because the manipulator must be coupled and uncoupled with the ladle slide gate mechanism each time a new ladle arrives at and leaves the respective holding device of the transport device: in order to ensure that the ladle shroud held by the robot follows the same movements as the collector nozzle (14), these movements being controlled by the drive means (17), the robot need not be synchronized with the drive means (17).

As shown in fig. 1(d), when the first ladle (11) is substantially empty, it must be replaced by a full second ladle (12) waiting at the loading station. In the embodiment illustrated in fig. 1, the turret (30) is configured for raising the first and second ladles (11, 12) to a rotational height to ensure that the ladle shroud (13a, 13b) of the first and second ladles do not collide with the tundish (1) or any other element of the casting apparatus when the turret is rotated. As shown in fig. 1(e), the turret (30) is also configured for rotation about a vertical axis (Z) so as to exchange the positions of the first ladle and the second ladle in a single movement, which are still maintained at a rotational height above the respective loading position and casting position. Finally, the turret (30) must be configured to lower the first ladle and the second ladle to their respective loading and casting stations, as shown in fig. 1 (f). Regardless of whether the manipulator (35) is fixed to the first and second holding means or to the ladle slide gate mechanism (15), the manipulator follows the lifting, rotating and lowering movements of both ladles.

The movement of the turret and the movement of the ladle slide gate mechanisms (15) of both the first and second ladles must be fully synchronized to prevent any unwanted dripping or run-off of molten metal from either of the first and second ladles.

The robot (21) must also be configured for removing the emptied first ladle (11) at the loading station from the corresponding manipulator (35) after it has disengaged the ladle shroud (13a) from the collector nozzle (14). The robot is further configured for decoupling the drive means (17). The used ladle shroud (13a) may be cleaned and stored for further use or may be discarded into a waste bin (27), as shown in figure 1 (f). The drive means (17) can be stored in a storage station on the first holding means of the turntable (30) without having to disconnect it from the source of pressurized fluid or stored in a storage rack (29) of the loading platform after it has been disconnected from the source of pressurized fluid. If the manipulator (35) is fixed to the ladle sliding gate mechanism (15), the robot is configured to decouple the manipulator from the ladle sliding gate mechanism and store the ladle sliding gate mechanism in a rack (29) for loading the next ladle onto the first holding means of the transport means. The first ladle (11), now emptied, both the ladle shroud (13a) and the drive means (17) and optionally the robot, can be removed to a service station for hot repair. A new ladle filled with molten metal can be tapped from the furnace and loaded onto the now empty first holding means of the turret to start the entire operation as illustrated in fig. 1(a) to 1(f) discussed above.

Robot (21)

The robot (21) may have at least five, preferably at least six or seven degrees of freedom. The robot is preferably movably mounted on the loading platform (20) such that the robot can translate parallel to the first axis (X) and/or a second axis (Y) perpendicular to the first axis (X), or a combination thereof. The robot (21) may preferably rotate about a vertical axis (Z) perpendicular to the first and second axes (X, Y). By a combination of these movements, the robot must be able to reach and retrieve any tools or components from the storage rack (29), and to reach the ladle slide gate mechanism (15) of the first or second ladle (11, 12) held at the loading station for the operations described below. Excellent results were obtained using a Kuka foundation robot KR 480.

The robot may include a base in communication with a motion generating component, such as a wheel or a pedal. The base may be in communication with the arm; the arm may be rotatably, fixedly, and/or pivotally attached to the base. The arms may be extendable. The arm may be provided with one or more sections joined to each other by a pivot or rotatable joint. The arm may be provided with holding means, such as clamps, housings, receptacles, supports, grippers or the like, configured for engaging, manipulating, handling, coupling, gripping and/or moving the drive means (17), ladle shroud (13a-13c), tool, or robot (35).

The robot is configured for coupling the drive device (17) to a ladle (11, 12) filled with molten metal and its ladle slide gate mechanism (15). The robot is further configured for removing the drive means (17) from the emptied first or second ladle (11, 12) held at the loading station after movement from the casting station. The robot (21) is configured for handling a new ladle shroud to the robot arm (35) and for removing a used ladle shroud (13a-13c) from the robot arm of an emptied ladle (11, 12). Finally, and only if the manipulator is not fixed to the first and second holding means of the transport means, the robot is configured for coupling and uncoupling the manipulator with the ladle at the loading station. In order to avoid severe thermal shock, the ladle shroud (13b) is preferably enclosed in a preheating station before it is coupled to the ladle slide gate mechanism (15) of the ladle at the loading station. The robot can transfer ladle shroud from storage rack (29) to a preheating station (not shown) and then to robot arm (35). Similarly, to remove a ladle shroud from an evacuated first ladle (11), the robot may grasp the ladle shroud from the robot after the robot disconnects the ladle shroud from the down nozzle. The robot may bring the removed ladle shroud to a pressurized gas (e.g. oxygen) cleaning station (not shown) and a preheating station or storage rack (29) for further use. Alternatively, if the ladle shroud is too worn to be used further, the robot can discard it into a waste bin (27) (see fig. 1 (f)).

The robot is further configured for inspecting the status of a used ladle shroud (13a-13c) after it has been removed from an evacuated ladle. In a preferred embodiment, the robot is configured to assess whether a used ladle shroud can be reused after cleaning or whether it has to be discarded. This can be achieved by artificial intelligence programming of the robot that can "learn" to distinguish between used ladle spouts that can be reused or used ladle spouts that must be discarded. The robot is also preferably configured to clean the used ladle shroud with an oxygen blower to remove any residue adhering to the walls of the used ladle shroud.

Steel ladle sliding nozzle mechanism (15)

A ladle slide gate mechanism (15) suitable for use in the present invention includes an upper plate (15u) and a lower plate (15 d). The upper plate includes a fixed surface and a bottom sliding surface spaced apart from each other by a thickness of the upper plate, and an upper hole extending from the fixed surface to the bottom sliding surface. The fixed surface of the upper plate is rigidly fixed to a lower portion of the respective first or second ladle (11, 12), wherein the upper aperture is in fluid communication with the opening (11o, 12 o). As shown in fig. 2(a) and 3(a), the opening is generally formed by the downstream end of the inner bore of the inner nozzle (18). The upper plate (15u) is fixed relative to the openings (11o, 12o) and the inner nozzle (18) during the entire casting operation from the ladle (11, 12) into the tundish (1).

The lower plate (15d) includes a gate surface and a top sliding surface spaced from each other by a thickness of the lower plate, and one or two lower holes extending from the top sliding surface to the gate surface. In a first embodiment, the lower plate comprises a single first lower aperture. In a second embodiment, the lower plate includes a first aperture and a second aperture. These two embodiments will be discussed in detail below. The lower plate (15d) is slidably mounted such that the top sliding surface can be translationally slid along the bottom sliding surface to bring the one or both lower apertures into and out of fluid communication with the upper aperture. The lower plate can be moved translationally by activating the drive means (17). The drive means may comprise a cylinder (17c) rigidly and reversibly coupled to a bottom portion of the first or second ladle (11, 12), and a piston (17p) reversibly fixed to the lower plate (15 d).

The drive means (17) may be actuated hydraulically or pneumatically or electrically. Each of the at least first and second holding means of the ladle turret is preferably provided with a source of pressurized fluid for actuating the drive means (17) via a hose (17 t). In a preferred embodiment, each of the at least first and second holding devices of the ladle turret further comprises a storage unit for storing the drive device (17) when the drive device (17) is not coupled to the ladle slide gate valve mechanism (15), as shown in fig. 1(a), 1(b) and 1 (f). The drive means (17) may also be stored in a storage rack on the loading platform. Preferably, however, the drive device (17) is stored on the first and second holding device, as in this way the drive device (17) can be permanently coupled to a hydraulic or pneumatic fluid source (17h) via a hose (17 t). This frees the robot (21) from having to perform the complex operations of coupling the hose (17t) to the most recently coupled drive(s) (17), which would have to be performed in the case of a drive (17) stored in a storage rack (29) on the loading platform.

The first embodiment: the lower plate (15d) comprises a single first lower hole

In the first embodiment illustrated in fig. 2(a) to 2(d), the lower plate (15d) includes a single first lower hole. The drain (14) is rigidly (and reversibly) coupled to the drain surface of the lower plate. The top sliding surface surrounds the inlet of the single first lower bore and has a surface area sufficient to seal the outlet of the upper bore (18) when the ladle slide gate valve mechanism is in the sealing position, as illustrated in fig. 2 (a). Ladle shroud (13a-13c) is coupled to the downcomer by a robot (35) wherein the downcomer is inserted into the ladle bore.

Fig. 2(a) to 2(d) show respective steps for starting a casting operation from a ladle (11, 12) to a tundish (1) by a ladle slide gate mechanism according to a first embodiment. Fig. 2(a) shows a new ladle (11, 12) having reached the casting station. The ladle slide gate valve mechanism is in a sealing position in which the single first hole of the lower plate (15d) is misaligned with the upper hole of the upper plate (15 u). The inner bore of the inner nozzle (18) and the upper bore are filled with a plugging material (19), which may be sand or any other particulate material, for preventing the sliding mechanism from freezing by the solidified metal. Since the downstream end of the upper bore is sealed by the lower plate, neither the molten metal (2) nor the plugging material (19) is allowed to flow through the ladle slide gate mechanism. Once the ladle is at the casting station, casting may begin.

To start casting, the drive means (17) translates the lower plate and ladle shroud (13a-13c) until the lower and ladle bores are in fluid communication with the upper bore, thereby forming a continuous flow path from the inner bore to the shroud bore, as shown in fig. 2 (b). As shown in fig. 2(a) to 2(d), if the robot arm (35) is coupled to the lower plate so as to move together with the lower plate, the ladle shroud (13a-13c) held in place by the robot arm moves together with the drain (14) fixed to the lower plate (15 d). As illustrated in fig. 1(a) to 1(f) and 6, if the manipulator is coupled to the first or second holding means of the transport means, the manipulator must be synchronized with the drive means so that when the lower plate (15d) of the ladle slide gate mechanism moves, the manipulator ensures that the ladle shroud follows the same motion as the lower plate and thus remains coupled to the downcomer (14) without damaging any parts.

Under normal conditions, the plugging material (19) flows out through the lower holes and the elongated tap holes driven by the pressure of the molten metal in the ladle. Once the plugging material (19) is drained, molten metal flows from the ladle through the elongated tap hole. This operation takes several seconds and the casting from the tundish to the crystallizer can be carried out continuously. However, as discussed in the background section, in some cases, the solidified mass of plugging material (19) may block the inner and upper holes so that molten metal cannot flow out of the ladle and the channel must be dredged. With the casting device according to the first embodiment of the invention, the blocked inner and/or upper bore can be dredged very quickly as follows.

As shown in fig. 2(c), the robot (35) decouples the ladle shroud (13a-13c) from the downcomer (14) by lowering and driving the ladle shroud away to access the downstream end of the downcomer bore. Since the collector nozzle is much shorter than the ladle shroud, leaving sufficient clearance above the tundish, it is easy to introduce a pull through tool (19r) through the downstream end of the collector nozzle, through the upper and lower bores and up to the inner bore. The pull through may be a metal rod which may be used to break up the solidified mass by impacting against this solidified plugging material. Alternatively, as shown in fig. 4(b), the dredging tool (19r) may be a pressurized gas lance which jets a pressurized gas jet such as oxygen. The pull through tool (19r) may be carried manually or by a robot (31) located at the casting station.

Once the solid mass has broken, particles of plugging material (19) begin to flow out through the drain. The manipulator (35) can bring the ladle long nozzle to the lower nozzle, wherein the ladle sliding nozzle mechanism is in a sealing position or a casting position. When in the sealing position, the manipulator can be slowly and leisurely connected with the ladle long nozzle. In the casting position, the coupling operation must be carried out rapidly to prevent the molten metal from flowing out of the collector nozzle before the ladle shroud is coupled to the collector nozzle. Once the ladle shroud is coupled to the collector nozzle, as shown in fig. 2(d), the ladle slide gate mechanism, if in the sealing position, must be brought to the casting position and casting can start normally.

Alternatively, the clogged hole in the ladle equipped with the ladle sliding gate mechanism (15) according to the first embodiment may also be dredged in the following manner as illustrated in fig. 4(a) to 4 (c). Fig. 4(a) shows a metal casting apparatus with a hollow first ladle (11) parked at a loading station before being removed and a full second ladle (12) positioned at the casting station with the lower plate (15d) of the ladle slide gate mechanism in the casting position. This case is equivalent to the case shown in fig. 2(b), in which the lower hole and the ladle hole are in fluid communication with the upper hole, thereby forming a continuous flow path from the inner hole to the elongated spout hole.

As discussed in the background section, if the inner bore and upper bore become blocked, preventing the flow of molten metal from the ladle, the passageway must be unblocked. With the casting apparatus according to the first embodiment of the present invention, the blocked inner and/or upper bore can be dredged very quickly as illustrated in fig. 4(a) to 4(c) below.

As shown in fig. 4(b), the turret (30) (or other transport means) raises the full second ladle (12) until the ladle shroud leaves the tundish with sufficient clearance above the top of the tundish to reach the outlet of the ladle shroud, as a break-through tool (19r) is introduced through the outlet of the ladle shroud, through the lower shroud opening, the lower bore, the upper bore and up to the inner bore. The pull through may be a metal rod which may be used to break up the solidified mass by impacting against this solidified plugging material. As shown in fig. 4(b), the dredging tool (19r) is preferably a pressurized gas spray gun which sprays a jet of pressurized gas such as oxygen. The pull through tool (19r) may be carried manually or by a robot (31) located on the casting platform at the casting station. In this embodiment, the pull through tool is preferably telescopic to facilitate introduction of the pull through tool through the outlet of the ladle shroud with minimal clearance. In an alternative embodiment, the pressurized gas lance (19r) may be integrated into the ladle shroud. This solution increases the cost of the ladle shroud used and requires the connection of the integrated lance to a source of pressurised gas prior to casting.

Once the solid mass has broken, particles of plugging material (19) begin to flow out through the collector nozzle and the ladle shroud. As shown in fig. 4(c), the turret (30) lowers the second ladle (12) to the casting position while the lower plate is in the sealing position or casting position. When in the sealing position, the revolving platform can make the ladle slowly and leisurely descend. In the casting position, the lowering operation must be carried out rapidly to prevent the molten metal from flowing out of the tundish before the ladle shroud is introduced into the tundish. At this stage, casting can start normally.

By lifting the ladle and ladle shroud away from the tundish, it is possible to unclog the upper and inner bores through the shroud bore, since the robot (35) is either fixed to the holding device, to the ladle, or to the ladle slide gate mechanism, and the robot (35) is lifted together with the ladle. In prior art metal casting plants, where the ladle shroud is held in place by a robot (31) on the casting platform at the casting station, this would not be possible because the robot (31) could not hold the ladle shroud in a high position as required by the present dredging method.

Fig. 4(a) to 4(c) also show the replacement of an empty ladle (12) parked at the loading station with a full new ladle (12 b). A new ladle (12b) filled with molten metal is taken from the furnace to the metal casting apparatus with a crane. A new ladle (12b) has been equipped with the ladle slide gate nozzle mechanism (15) in a sealed position, with the down gate (14) coupled to the lower plate (15d) of the ladle slide gate nozzle mechanism, but the new ladle does not carry any ladle shroud (13a-13c) and any drive means (17). Once a new ladle (12b) is loaded onto the turret (30), the robot (21) can hand the new ladle shroud (13c) to the robot arm (35) and the drive means (17) can be coupled to the ladle slide shroud mechanism as explained above.

Second embodiment: the lower plate (15d) includes a first hole and a second hole

In a second embodiment illustrated in fig. 3(a) to 3(d), the lower plate (15d) comprises a first lower hole and a second lower hole, each extending from the top sliding surface to the nozzle surface. The lower plate (15d) is slidably mounted such that the top sliding surface can slide along the bottom sliding surface to bring each of the first and second lower apertures into and out of fluid communication with the upper aperture. The first and second drain ports (14) are rigidly and reversibly coupled to the port surface, wherein the drain port bores of the first and second drain ports (14) are in fluid communication with the first and second drain bores, respectively. The top sliding surface surrounds the inlets of both the first and second lower apertures and has a surface area sufficient to seal the outlet of the upper aperture when the ladle slide gate valve mechanism is in the sealing position, as illustrated in fig. 3 (a). Ladle shroud (13a-13c) is coupled by a robot (35) to a first lower nozzle, wherein the first lower nozzle is nested in the ladle bore.

Fig. 3(a) to 3(d) show respective steps for starting a casting operation from a ladle (11, 12) to a tundish (1) by a ladle slide gate mechanism according to a second embodiment. Fig. 3(a) shows a new ladle (11, 12) having reached the casting station. The ladle slide gate mechanism is in a sealing position in which both the first lower hole and the second lower hole of the lower plate (15d) are misaligned with the upper hole of the upper plate (15 u). The inner bore of the inner nozzle (18) and the upper bore are filled with a plugging material (19), which may be sand or any other particulate material, for preventing the sliding mechanism from freezing by the solidified metal. Neither the molten metal (2) nor the plugging material (19) is allowed to flow through the ladle since the downstream end of the upper bore is sealed by the lower plate. Once the ladle is at the casting station, casting may begin.

To start casting, the drive means (17) translates the lower plate and ladle shroud (13a-13c) until the first lower and ladle holes are in fluid communication with the upper hole, thereby forming a continuous flow path from the inner bore to the shroud opening, as shown in fig. 3 (b). As shown in fig. 3(a) to 3(d), if the robot arm (35) is coupled to the lower plate so as to move together with the lower plate, the ladle shroud (13a-13c) held in place by the robot arm moves together with the drain (14) fixed to the lower plate (15 d). As illustrated in fig. 1(a) to 1(f) and 6, if the manipulator is coupled to the first or second holding means of the transport means, the manipulator must be synchronized with the drive means so that when the lower plate (15d) of the ladle slide gate mechanism moves, the manipulator ensures that the ladle shroud follows the same motion as the lower plate and thus remains coupled to the downcomer (14) without damaging any parts.

Under normal conditions, the plugging material (19) flows out through the lower holes and the elongated tap holes driven by the pressure of the molten metal in the ladle. Once the plugging material (19) is drained, molten metal flows from the ladle through the elongated tap hole. This operation takes several seconds and the casting from the tundish to the crystallizer can be carried out continuously. However, as discussed in the background section, in some cases, the solidified mass of plugging material (19) may block the inner and upper holes so that molten metal cannot flow out of the ladle and the channel must be dredged. With the casting device according to the first embodiment of the invention, the blocked inner and/or upper bore can be dredged very quickly as follows.

As shown in fig. 3(c), the lower plate (15d) is moved to place the second lower holes in fluid communication with the upper holes. Unlike the dredging method discussed above in connection with fig. 2(a) to 2(d), the ladle shroud (13a-13c) may remain coupled with the first downcomer throughout the dredging operation. Since the second collector nozzle does not have any ladle shroud and is therefore much shorter than the first collector nozzle to which the ladle shroud is coupled, there is sufficient clearance left below the second collector nozzle above the tundish. Therefore, as shown in fig. 3(c), it is easy to introduce the dredging tool (19r) through the downstream end of the second collector nozzle, through the second lower hole, the upper hole and up to the inner hole. The pull through may be a metal rod which may be used to break up the solidified mass by impacting against this solidified plugging material. Alternatively, as shown in fig. 4(b), the dredging tool (19r) may be a pressurized gas lance which jets a pressurized gas jet such as oxygen. The pull through tool (19r) may be carried manually or by a robot (31) located on the casting platform at the casting station.

Once the solid mass has broken, particles of plugging material (19) begin to flow out through the drain. As shown in fig. 3(d), the lower plate may be moved to a casting position wherein the first lower nozzle and the ladle shroud coupled thereto are in fluid communication with the bore. At this point, casting can be started and carried out normally.

Mechanical arm (35)

The manipulator (35) may be considered a simplified robot, having fewer degrees of freedom, and configured to perform a limited number of rather simple movements. The robot comprises an arm (35a) provided at one end with gripping elements (35g) for firmly gripping a ladle shroud received from the robot (21) and for releasing the ladle shroud when the robot is ready to remove it from an emptied ladle (11, 12). The manipulator is configured for allowing, on the one hand, the arm (35a) to move up and down along a direction parallel to the axis (Z) of the lower mouth hole, and, on the other hand, the gripping element (35g) to move along a plane parallel to the planes (X, Y) perpendicular to the axis (Z).

For coupling the ladle shroud to the collector nozzle, movement of the gripping element in the plane (X, Y) allows positioning the ladle shroud in alignment with the collector nozzle (14) and upward movement along the axis (Z) of the arm (35a) allows coupling the ladle shroud to the collector nozzle inserted into the upstream end of the ladle shroud bore as shown in fig. 2(a), 2(b) and 2 (d).

For uncoupling the ladle shroud from the collector nozzle (14), moving downwards along the axis (Z) of the arm (35a) allows uncoupling the ladle shroud from the collector nozzle, leaving sufficient clearance for the gripping element to move the ladle shroud on a plane (X, Y) so that the collector nozzle hole is accessible for dredging the hole, as shown in fig. 2(c), or to carry it to a robot (21) for removing the ladle shroud for hot repair or discarding, as shown in fig. 1(e) and 1 (f).

In an embodiment, the manipulator comprises a piston (35p) configured for driving upward and downward movements parallel to the axis (Z) (see fig. 5(a) to 5(c) and 6). The arm (35a) is configured for rotation about a central axis of the piston parallel to the axis (Z) (see fig. 5(b) and the chain line centered on the piston (35p) in fig. 6). In the simplest form illustrated in fig. 5(a) to 5(c), the robot (35) is coupled directly or indirectly to the lower plate (15d) to follow its movement, and the arm (35a) may have a fixed length and its rotation about the central axis of the piston (35p) is sufficient to align or misalign the ladle shroud with the downcomer (14). In fig. 5(a) the robot is lowered and out of position alignment with the downcomer (14) to receive a new ladle shroud (13a) from the robot (21). The robot aligns and locates the ladle shroud with and below the collector nozzle by rotating about an axis parallel to the collector nozzle bore axis, as shown in fig. 5 (b). By raising the ladle shroud, as shown in fig. 5(c), the robot couples the ladle shroud to the collector nozzle, which is nested in the ladle shroud. The manipulator can maintain the ladle shroud in this position as long as required. In this embodiment, no further degrees of freedom are required, since the robot moves together with the lower plate (15d) and the drain (14). If the manipulator (35) is fixed to the respective first and second holding means, the manipulator must have an additional degree of freedom as shown in fig. 6 to allow the ladle shroud to follow the movements of the lower plate and the collector nozzle (14). In this case, it is necessary to synchronize the movement of the robot with the movement of the base plate driven by the driving means (17).

The removal of the used ladle shroud is performed in reverse order from fig. 5(c) to fig. 5(a) with reverse arrows. The used ladle shroud is decoupled from the collector nozzle by lowering it (see fig. 5(c) and 5 (b)). The used ladle shroud can be handed over to the robot (21) by the rotation of the robot arm (see fig. 5 (a)).

However, in a preferred embodiment, in order to allow the grip element (35g) to reach any point parallel to the plane of (X, Y), the arm (35a) may be formed by a telescopic piston, or alternatively, as illustrated in fig. 6, it may be constituted by two or more arm sections rotationally coupled to each other. The movement of the robot (35) is preferably driven hydraulically, pneumatically or electrically. As shown in fig. 6, the drive means (17) may be stored on the first and second holding means, preferably on the static part of the respective manipulator, sharing a hydraulic or pneumatic or electrical current source with the manipulator.

As mentioned above, the robot may be fixed to the first and second holding devices of the transport device (or to a part of the respective robot that is stationary with respect to the holding devices), as shown in fig. 1 and 3. This solution is advantageous in that the manipulator remains coupled with the transport device even when a new ladle (12b) is loaded onto the holding device or an emptied ladle is taken away from the holding device.

Alternatively, the manipulator may be fixed to the ladle slide gate mechanism (15), preferably moving together with the lower plate (15d), as illustrated in fig. 2(a) to 2(d), 3(a) to 3(d), and 5(a) to 5 (c). This solution has the following advantages: in order to ensure that the ladle shroud held by the robot follows the same movements as the collector nozzle (14), these movements being controlled by the drive means (17), the robot need not be synchronized with the drive means (17). On the other hand, the manipulator has to be re-fixed to the ladle slide gate mechanism (15) each time a new ladle (12b) is loaded onto the holding device, and has to be removed each time an empty ladle is removed from the transport device.

Method for casting molten metal

The invention also relates to a method for casting molten metal (2) from ladles (11, 12) into a tundish (1) in a casting apparatus as discussed above, wherein a first ladle (11) is filled with molten metal and located at a casting station, and a second ladle (12) is filled with molten metal and located at a loading station. As illustrated in fig. 1(a), the ladle slide gate mechanism (15) of the first ladle (11) is in a sealed position and is provided with ladle longnozzles (13a-13c) which are held in place on the downcomer (14) by a robot (35). The lower plate (15d) of the ladle sliding nozzle mechanism is connected with a driving device (17). The ladle slide gate mechanism (15) of the second ladle (12) is in a sealed position and includes a collector nozzle (14) but not a ladle shroud. The ladle slide gate mechanism (15) of the second ladle (12) is not coupled to any drive means (17).

To start casting of molten metal from a first ladle (11) through a ladle shroud (13a) into a tundish (1), a ladle slide gate mechanism (15) of the first ladle (11) is brought into a casting position. This operation is performed by actuating the drive means (17). The first ladle (11) discharges the molten metal (2) contained therein into the tundish (1) until the first ladle is considered empty.

When the first ladle (11) is discharging its contents into the tundish, the robot (21) carries the new ladle shroud (13b) to the robot (35), which is fixed to the second holding means (see fig. 1 (b)). As illustrated in fig. 1(c), on the one hand, the robot (35) couples this received ladle shroud to the ladle slide gate valve mechanism (15) of the second ladle (12), and on the other hand, the robot (21) couples the drive means (17) to the slide gate valve mechanism (15) of the second ladle (12). As discussed above, the operation of the above-mentioned further aspect becomes simpler if the first and second holding means of the turret (30) are provided with a storage unit for storing one or more drive means (17), since the one or more drive means may thus remain coupled with the source (17h) of pressurized fluid via the hose (17t) during the entire casting operation involving emptying of several (more than two) ladles into the tundish. If one or more drive devices (17) are stored elsewhere, typically in storage racks (29) on the loading platform (20), the robot (21) must additionally couple one or more hoses (17t) to the respective one or more drive devices in order for them to operate. The ladle slide gate mechanism remains in the sealing position throughout operation on the second ladle (12).

As shown in fig. 1(d), the ladle slide gate mechanism (15) of the first ladle (11) is brought from the casting position into the sealing position to interrupt any flow of molten metal from the first ladle (11) when the first ladle is substantially empty. The positions of the first ladle and the second ladle are exchanged by moving the first ladle (11) from the casting station to the loading station and concomitantly moving the second ladle (12) from the loading station to the casting station. The exchange of the positions of the first and second ladles (11, 12) may be performed as follows. Fig. 1(d) shows how the turret (30) raises the first and second ladles (11, 12) until the ladle longnozzles (13a, 13b) of both the first and second ladles are clear of the tundish and are higher in the vertical direction (Z) than the tundish, thereby defining a swivel height. Thus, the turret can be rotated without any risk of the ladle shroud (13a, 13b) of the first or second ladle (11, 12) colliding with the tundish or any other component of the casting apparatus. Fig. 1(e) shows the turret rotated 180 ° about the vertical axis (Z) so that the first ladle (11) emptied is higher than the loading station and the second ladle (12) filled is higher than the casting station and higher than the tundish (1). The first ladle and the second ladle are kept at their rotating heights all the time during the rotating operation. At this stage, the first and second ladles (11, 12) may be lowered to their respective loading and casting stations, the ladle shroud (13b) of the second ladle being inserted into the tundish (1).

The ladle slide gate mechanism (15) of the second ladle (12) may be brought into a casting position so that molten metal may flow from the second ladle (12) through the ladle shroud (13b) into the tundish (1). The entire exchange operation from closing the ladle sliding gate valve mechanism of the first ladle (11) to opening the ladle sliding gate valve mechanism of the second ladle (12) may last less than 2min, preferably less than 1min, and more preferably less than 30s, and the level of the molten metal in the tundish may be easily restored to a fixed casting level.

If the manipulator (35) is fixed to the respective holding means of the transport device, it must be configured for synchronously following the movement of the lower plate (15d) of the ladle slide gate mechanism (15) so that the collector nozzle (14) and the ladle shroud (13a-13c) are always nested one inside the other. If the manipulator (35) is fixed to the lower plate (15d) or any element of the ladle slide gate mechanism that is stationary with respect to the lower plate (15d), it is not necessary to synchronize the movement of the manipulator (35) with the movement of the drive means (17) because the manipulator moves with the lower plate (15 d).

The ladle shroud of the evacuated first ladle (11) parked at the loading station can now be dismantled to allow it to be removed and transported across the workshop to a hot repair station (not shown). The manipulator (35) disconnects the used ladle shroud from the downcomer (14) by lowering it along the central axis of the downcomer bore, and hands it over to the robot (21). The used ladle shroud (13a) may be stored for hot repair and cleaning (not shown) or may be discarded as waste to a waste bin (27) as shown in figure 1 (f).

As illustrated in fig. 1(f), the robot (21) may decouple and remove the one or more drive devices (17) from the sliding gate valve mechanism (15) of the first ladle (11) and store the one or more drive devices for further use. If the first and second holding means of the turntable (30) are provided with a storage unit for storing one or more drive means (17), the robot (21) does not need to disconnect the respective one or more hoses (17t) before storing the one or more drive means, since the hydraulic or pneumatic fluid (17h) or electrical power source is also located on the first and second holding means. On the other hand, if the one or more drive devices (17) are to be stored in a storage rack (29) located on the loading platform (20), the robot must also disconnect the one or more hoses (17t) from the respective one or more drive devices (17) before storing the one or more drive devices in the storage rack (29). The same applies if the drive device has to be replaced due to a defect.

The emptied first ladle, from which the ladle shroud (13a) and the one or more drive means (17) have been dismantled, can be removed from the first holding means with a crane to a hot repair station (not shown) where the ladle can be cleaned, repaired, and prepared for filling with a new charge of molten metal from the furnace. A new ladle filled with molten metal can be loaded onto the now empty first holding means of the ladle turret (30) at a loading station, wherein the new ladle comprises the ladle slide gate mechanism (15) in a sealed position and comprises the collector nozzle but not the ladle shroud (13a-13c) and the drive means (17) as in the second ladle (12) in the previous step. The cycle depicted in fig. 1(a) to 1(f) can thus be repeated and casting from the tundish to the mould can be carried out continuously, wherein the level of molten metal in the tundish is substantially constant throughout the continuous casting operation and there is little fluctuation in the exchange of the positions of the emptied ladle (11) and the filled ladle (12) as defined in the preceding steps. The fluctuations can be very small because the switching operation is very fast when the operation is optimal.

In case the step of exchanging the position of the first and second ladle is not performed optimally, the inner bore and/or the upper bore can be dredged quickly and efficiently by passing the lower nozzle bore with a suitable dredging tool (19r), as described above with reference to fig. 2(a) to 2(d), 3(a) to 3(d) and 4(a) to 4(c) in the section entitled "ladle sliding gate valve mechanism (15)", since the inner bore and/or the upper bore is blocked by the solidified plugging material. In this way, interruption of metal flow into the tundish is minimized. Without these options for quickly unblocking the casting channel, many operators are reluctant to couple the ladle shroud (13a-13c) to the bottom of the ladle at the loading station, whether or not there is a robot (21), because unblocking the inner and upper bores in the case of a ladle shroud coupled to a ladle slide gate mechanism requires returning the blocked ladle to the loading station and replacing the ladle shroud with a lower shroud to allow unblocking with an unblocking tool (19r) and then re-coupling the ladle shroud and returning the ladle to the casting station. All these operations take too long and there is a risk of the metal freezing, which should be prevented by using a plugging material. Furthermore, the prolonged absence of molten metal from the tundish may cause interruptions in the casting operation, which must be avoided in all cases.

In a preferred embodiment, the loading operation of the second ladle (12) resting at the loading station is carried out in the following order: the drive(s) are coupled to the ladle slide gate mechanism (15) followed by handling the new ladle shroud (13b) to the robot (35) and coupling the new ladle shroud to the downcomer (14). Preferably, the unloading operation of the emptied first ladle (11) staying at the loading station is carried out in the following order: the used ladle shroud (13b) is disconnected by a robot (35), the used ladle shroud is carried to a robot (21), and then the drive device(s) is disconnected from the ladle slide gate mechanism (15).

Advantages of the invention

The present invention provides an automated metal casting plant in which fresh ladles can be prepared for casting by a robot (21) at a loading station without any additional risk of interrupting the casting into the mould, compared to conventional metal casting plants. The present invention has at least the following advantages.

The robot is no longer necessary on the casting platform of the casting station. Many plants do not have the required space at the casting station. By means of the invention, a robot is installed at the loading station where there is more space available for installing the robot on the loading platform (20) to hand over the ladle shroud (13a-13c) to a manipulator (35) for coupling the ladle shroud to a newly filled ladle (12) on the loading station before the newly filled ladle reaches the casting station. Front end robots are generally available at the casting stations of many casting plants. As explained above, the front end robot is still useful in case the inner and/or upper bore is blocked and the robot (35) disengages the ladle shroud from the collector nozzle, e.g. for handling a pull through tool (19 r).

The invention greatly reduces the time to strip (steel off time) between ladle changes, since all handling and preparation of a newly filled ladle (12) for casting is done at the loading station during the casting time of the first ladle (11) held at the casting station. Shorter ladle stripping time

A lower drop in the steel level in the tundish (1) occurs,

better steel quality protection results because there is no need to reduce the casting speed during ladle replacement.

In the case of a blockage of the inner and/or upper bore, the dredging operation can be carried out similarly to when the ladle shroud is held in place in existing metal casting plants with a robot or front end robot, with the additional advantage that the robot or front end robot is available at the casting station, which is free to be used at will while the robot (35) holds the ladle shroud (13a-13 c).