EP0621097A1 - Set of ceramic elements for a casting gate and method of changing this set - Google Patents

Abstract

Set of ceramic (refractory) elements for a casting gate (10), comprising a metallic reinforcement (12) mounted on a metallurgical vessel (1), a stationary ceramic plate (14) including a port (14a), a movable ceramic plate (16) including a port (16a), a collector nozzle (42), displacement means for displacing the movable plate (14) with respect to the stationary plate (16) so as to control the covering-over of the port of the stationary plate by the port of the movable plate. Pressure means (26) make it possible to press the movable plate against the stationary plate, a stationary ceramic plate (14) and a movable ceramic plate (16) and the collector nozzle (42) are capable of being linked together so as to constitute a set which may be introduced into and/or removed from the casting gate (10) in a single operation. <IMAGE>

Description

The invention relates to a set of refractory elements, in particular for a pouring shutter, said pouring shutter comprising a metal frame mounted on a metallurgical container, at least one fixed refractory plate, comprising at least one pouring orifice, at least one movable refractory plate, comprising at least one pouring orifice, at least one collecting nozzle made integral with the movable plate, displacement means for moving said at least one movable plate relative to said at least one fixed plate so as to control the covering the orifice of the fixed plate and the movable plate; pressure means which make it possible to clamp said at least one movable plate against said at least one fixed plate.

In a device of this type, the metal parts of the shutter (metal frame in particular) generally have a lifespan of several hundred, or even several thousand flows. On the other hand, the refractory elements (fixed and mobile plates, as well as the pouring nozzle) have a lifetime of a few castings and must therefore be changed frequently.

Two methods are currently used to change these refractories.

According to a first method, each refractory element is changed individually. In certain embodiments, the collecting nozzle can be reached from outside the metal frame, but access to the plates to be changed requires opening this metal frame. For example, the flow shutter has a door mounted on hinges. This door can be opened to give access to the refractories. Each refractory plate is removed individually and replaced by a new plate (with or without a metal casing). This method is well suited when the refractory elements to be handled are light enough that it is easy to replace them manually and provided that the access and ambient conditions allow the operator to access them easily and without danger .

On the other hand, in the case of large shutters, such as those used for steel furnaces, converters or large ladles, each refractory element can reach a weight of several tens of kilos. Furthermore, particularly in the case of ovens and converters which, unlike pockets and distributors, cannot be moved outside of their working environment, the change of refractory elements must be carried out on site under conditions very difficult for the operator, in particular because of the temperature. These conditions are further aggravated since one cannot generally wait for the shutter to cool down because the time required to change plates, which involves production stoppage and therefore loss, must be reduced to a minimum. The working conditions are therefore particularly harsh.

We could consider assisting operators with tools such as robots or manipulators. For such tools, the weight is not a disadvantage. The critical factor is the number of manipulations to perform. The handling time required to make a plate change using a manipulator would be much greater than what would be required for an operator to make the same change manually. Each gripper must be adapted to the object to be handled. Such a solution would therefore be extremely expensive, complex and time consuming.

According to a second known method, the complete casting shutter is removed from the container and replaced by a new shutter containing new refractories. This method also has many drawbacks. Indeed the complete shutter weighs much more than the refractory to exchange, for example twenty times more. Thus, if the refractories weigh 100 kg, it will be necessary to handle a two-ton element, which implies powerful tools and increased handling time.

It is also necessary to disconnect and reconnect the actuator which is used to drive the moving plate, to remove and replace the various protective shields, etc. In total, the time required and the number of operations are increased. On the other hand, the shutter containing the used refractories must be transported to a workshop where one proceeds to the replacement of the used refractories by new refractories. Working conditions are therefore easier, particularly with regard to temperature and accessibility. Time is also a less critical factor because production can continue during this time. However the number of operations to be carried out to exchange the refractory elements remains the same and moreover it is necessary to finance transport and the workshop.

The present invention relates to a set of refractory elements comprising the refractory elements to be exchanged in a flow shutter which overcomes the drawbacks of the two methods described above. It also relates to a method for performing the replacement of this set of refractory elements.

The set of refractory elements according to the invention is characterized in that the collecting nozzle is secured to the movable plate and in that said at least one fixed refractory plate and said at least one movable refractory plate are capable of being linked between them so as to constitute a clearance which can be introduced into and / or removed from the shutter in a single operation.

The method for replacing the set of refractory elements of a pouring shutter, said shutter comprising a metal frame mounted on a metallurgical container, at least one fixed refractory plate comprising at least one orifice, at least one mobile refractory plate comprising at least an orifice, displacement means for moving the movable plate relative to the fixed plate so as to control the covering of the orifice of the fixed plate and of the movable plate; pressure means which make it possible to clamp the movable plate against the fixed plate is characterized in that one sets up and / or removes the refractory clearance in a single operation.

In a first step, the set of used refractories is removed in a single operation, and in a second step, a new set of new refractories is replaced. It follows that a single gripper and a single movement are sufficient, whereas according to the prior art, a gripper and a specific movement by refractory element were necessary. The handling time is greatly reduced because the handling of each of the elements is replaced by a single overall handling. Automation is made easier by the uniqueness of the movement. The number of manipulations to be performed is reduced in a ratio of 2 to 3.

Because handling is faster and simpler, it is possible to perform it on site (in situ) without having to use the second method of the prior art described above in which the entire shutter for casting is removed for disassembly in a special workshop. As a result, the advantage of the first method is retained. The weight of the part to be handled is limited to the weight of the refractory elements possibly associated with a metal casing directly mounted on each of these elements. This is advantageous because the handling tool does not have to be adapted to an excessively heavy load.

• la figure 1 est une vue d'ensemble d'un convertisseur et d'un obturateur à tiroir monté sur ce convertisseur ;
• la figure 2 est une vue d'ensemble en coupe longitudinale d'un obturateur de coulée, tel que celui représenté sur la figure 1 ;
• la figure 3 est une vue en coupe selon a plan perpendiculaire à celui de la figure 1 et qui montre le détail des moyens de liaison de la plaque réfractaire fixe et de la plaque réfractaire mobile ;
• la figure 4 est une vue de l'obturateur des fig. 2 et 3 représenté dans une autre position.
• la figure 5 est une vue schématique d'une variante de réalisation dans laquelle les moyens de liaison sont disposés sur l'enveloppe des plaques réfractaires ;
• la figure 6 est une variante de réalisation dans laquelle les moyens de liaison sont situés sur l'enveloppe métallique de la plaque fixe et sur un cadre dans lequel est enchâssée la plaque mobile ;
• la figure 7 est une vue de l'extrémité d'un préhenseur destiné à être utilisé dans une variante du procédé de l'invention ;

On a représenté sur la figure 1 une vue d'ensemble d'un convertisseur 1 pour l'élaboration de l'acier. Un obturateur à tiroir, désigné par la référence générale 10, est fixé sous le convertisseur 1. L'acier contenu dans ce convertisseur est versé dans une poche 3 par un trou de coulée.Other characteristics and advantages of the present invention will appear on reading the following description of exemplary embodiments given by way of illustration and in no way limitative with reference to the appended figures in which:

• Figure 1 is an overall view of a converter and a slide valve mounted on this converter;
• Figure 2 is an overall view in longitudinal section of a flow shutter, such as that shown in Figure 1;
• Figure 3 is a sectional view along a plane perpendicular to that of Figure 1 and showing the detail of the connecting means of the fixed refractory plate and the movable refractory plate;
• Figure 4 is a view of the shutter of Figs. 2 and 3 shown in another position.
• Figure 5 is a schematic view of an alternative embodiment in which the connecting means are arranged on the envelope of the refractory plates;
• Figure 6 is an alternative embodiment in which the connecting means are located on the metal casing of the fixed plate and on a frame in which is embedded the movable plate;
• FIG. 7 is a view of the end of a gripper intended for use in a variant of the method of the invention;

There is shown in Figure 1 an overview of a converter 1 for the production of steel. A drawer shutter, designated by the general reference 10, is fixed under the converter 1. The steel contained in this converter is poured into a pocket 3 through a tap hole.

There is shown in Figure 2 a sectional view of the slide valve shutter 10 mounted on the converter 1. This shutter consists of a metal frame 12 fixed on the outer wall of the converter. In this frame there is a set of two plates, namely a fixed plate 14 and a movable plate 16. Each of these plates has an orifice, respectively 14a, 16a for the passage of the metal. Pressure means make it possible to press the movable plate 16 against the fixed plate 14 and the latter against a plate 36 mounted in a recess in the frame 12. These pressure means will be described in more detail with reference to FIG. 3.

The fixed plate is placed in a frame, known as the fixed plate drive frame 20, and the movable plate in a drive frame 22 of the movable plate 16. The rod 44 of the jack is retained in a housing of the frame d drive of the movable plate 22. The jack makes it possible to move the movable plate on the fixed plate.

This movement allows, in known manner, to vary the overlap of the orifices 14a and 16a of the two plates so as to control or completely stop the passage of the metal. It will be noted that, in the example shown, the shutter comprises a total of three plates, namely the junction plate 36, the fixed plate 14 and the mobile plate 16. But only the fixed plates 14 and mobile 16 are plates of work which support erosion on contact with liquid metal. On the contrary, the junction plate 36 does not see the steel in the sense that it is only changed when the converter 1 is empty. Although, in the example shown, the drawer shutter has only two working plates in addition to the junction plate, it could include more, for example three or more.

By set of refractory elements is meant, in the example shown, the fixed plate 14, possibly surrounded by a metal casing 38, and the movable plate 16 associated with the pouring nozzle 42, the plate 16 and the pouring nozzle 42 being mounted in a metal casing 40. On the other hand, the set of refractories does not include the junction plate 36 fixed to the internal nozzle 36a.

The envelope 40 assembles the movable plate 16 and the nozzle 42. It provides the assembly with sufficient rigidity to serve as a bearing surface for pressure means which will be described later. It further comprises a shield 40a which protects against radiation and projections.

The weight of the refractory set is reduced to the minimum compatible with these functions. There is shown in Figure 3, a sectional view of the embodiment of Figure 2 along a perpendicular plane. This figure shows the detail of the pressure means, generally designated by the general reference 26. They comprise a lever 100. At one end the lever is fixed to a torsion bar 102 shown in cross section. At its other end, the lever 100 is applied to a slide 104. The slide 104 is fixed to the metal casing 40. The force of the lever is transmitted to the plate 16, then to the plate 14 which is supported on the plate of junction 36. A static sealing is thus ensured between the fixed plate 14 and the junction plate 36 and a dynamic sealing is ensured between the plates 14 and 16. It will be noted that the means for clamping the fixed plate against the junction surface of the orifice casting are the same as the pressure means for pressing the fixed plate 14 against the movable plate 16. The same means therefore fulfill two distinct functions.

According to the invention, the metal casing 38 which surrounds the fixed plate 14 comprises a housing 38a. A tongue 106 is fixed on the metal casing 40 which surrounds the movable plate 16 and the collecting nozzle 42. This tongue 106 comes to lock in the housing 38a. The tongue 106 and the housing 38 constitute the means which make it possible to link the refractory elements so that they form a play which can be introduced and / or removed in one piece, and consequently, in a single operation of the shutter 10. More specifically, in the example shown, the set includes not only the fixed and movable plates themselves, but also the envelopes 38 and 40 and the nozzle 42. It is this assembly which is introduced and / or removed in one operation. It is true that the weight to be handled is increased compared to the weight of the refractories alone. However, this increase in weight remains reasonable.

Returning to FIG. 2, we will now describe in detail the means for securing the drive frame 20 of the fixed plate either with the frame 1 or with the drive frame of the movable plate 22. These means are constituted by a latch with 2 positions 50. This lock is mounted on the drive frame 20 of the fixed plate. In a first position, shown in Figure 1, it enters a housing 51 of the frame 2. In its other position it enters a housing 3 provided in the drive frame 22 of the movable plate. In the first position it immobilizes the drive frame of the fixed plate relative to the frame and, in its second position, relative to the drive frame of the movable plate. The cylinder has a sufficient stroke to move the assembly of the two frames 20 and 22 sufficiently to release the set of refractory elements from the grip of the pressure means of the fixed plate against the junction surface of the pouring orifice.

Thanks to the two-position lock, the same means, namely the cylinder successively performs two distinct functions. On the one hand it allows to move the movable plate on the fixed plate (first position of the latch 50). On the other hand it is used during the extraction of the part to change the establishment of a new fixed plate. For this the lock is placed in its second position, which allows to move in one piece the drive frame of the fixed plate and the drive frame of the movable plate secured together by the lock 50. The game of refractory to change is moved at the same time as frames 20 and 22.

There is shown in Fig 4, the drawer of Fig 3 in the open position. Note that the latch 50 is placed in said second position in which it secures the drive frame 20 of the fixed plate 14 with the drive frame 22 of the movable plate 16. the jack 28, the rod 44 of which is connected at the carriage 22 for driving the movable plate, was used to push the assembly constituted by the two drive frames (fixed and movable) and the plates housed in the openings of these frames (fixed plate 14 and movable plate 16 ). This movement has been continued sufficiently so that the set of refractories is entirely freed from the action of pressure means 26. The openings of the frames 20 and 22 being superimposed, the set of refractories can be removed freely without having to open a door as this is generally done in the devices of the prior art. It is not necessary to make any connection or disconnection because the cylinder rod remains fixed, during these operations, on the drive frame of the movable plate. The assembly to be changed, constituted as previously said of the fixed refractory plate 14, of the movable refractory plate 16, of the casing 38 of the fixed plate 14 and of the casing 40 of the movable plate 16 is evacuated in a single operation by means of a gripper. A replacement assembly, comprising new refractories, is then brought in using the same manipulator or a different gripper.

The actuator is then actuated to pull the assembly which penetrates laterally relative to the pouring orifice under the locking means 26, which positions the two plates without any other additional operation. The fixed plate 14 is slid under pressure means 30 before the fixed plate 14 begins to cover the pouring orifice.

We see that this embodiment has a double advantage. On the one hand it allows, in accordance with the invention, to change the set of refractories in a single operation instead of having to successively manipulate the various refractory plates. This is an important advantage in the case where the set of refractories comprises two plates as in the example shown. This characteristic saves time important. This time saving is increased when two grippers are used, one for removing the used refractories, the other for setting up a set of new refractories. The two grippers do not perform the same function because it is easier to remove the used set of refractories than to install a new set of refractories. The gripper used for removal therefore does not need to be very sophisticated.

The fact of using two grippers makes it possible to keep ready that of the two which is used for the installation of the set of new refractories. It can enter into action as soon as the used refractories have been evacuated. This saves precious time, particularly in the case of converters for which it is desirable that the time necessary for the exchange of refractories remains less than a few minutes.

On the other hand, the embodiment shown has yet another advantage.

In fact, in the prior art casting shutters, access to the refractory to be exchanged is obtained by means of a door pivotally mounted on hinges. Before you can access the refractories, it is necessary to open this door. When the refractories have been changed, the door must be closed before the shutter can be put back into operation. These two additional operations take time. Furthermore, they cannot be easily automated.

We see that, according to the embodiment shown, it is not necessary to open and close a door to access the refractories. These are evacuated and put in place by sliding the assembly to change, which eliminates a step. On the other hand this operation can be carried out easily because it does not require manual intervention but can on the contrary be carried out in a simple way thanks to a jack. It will also be noted that this jack is the same as that which is used conventionally for regulating the casting. It is therefore not necessary to provide additional equipment.

FIG. 5 shows an alternative embodiment of the invention. In this variant, the fixed refractory plate 14 is surrounded by a metal casing 110, for example made of sheet steel. The movable refractory plate 16 is also surrounded by a metal casing made of sheet steel 112. In the example shown a nozzle is integral with this fixed refractory plate. The metal casing of the fixed retractable plate is folded so as to constitute a flange 114. The casing metal 112 of the movable refractory plate is folded over the rim 114 of the metallic casing of the fixed refractory plate so as to constitute a slide 116. This slide constitutes the connection which makes it possible to set up and / or remove the plate fixed refractory and the movable refractory plate in a single operation of the pouring shutter. It goes without saying in the case where the set of refractory plates comprises more than two plates, each of these plates may comprise a clean metal envelope, each refractory plate being made integral with the neighboring refractory plate by means of a slide similar to that which has just been described. In a vertical handling position, the slide could allow the two plates to separate. This drawback is overcome, in accordance with the invention, by equipping the slides with end-of-travel stops limiting the travel of the sliding movement. This stroke must however remain sufficient to allow normal operation of the pouring shutter when the plates have been put in place.

There is shown in Figure 6 an alternative embodiment of the device shown in Figure 5. In this variant the fixed refractory plate 14 includes a metal casing 110, in a manner identical to that which has been described with reference to Figure 5. In however the movable refractory plate 16 and the pouring nozzle 42 are placed in a rigid metal frame 120. This metal frame has a groove 122 in which the flange 114 of the metal casing 110 of the fixed refractory plate is housed so as to constitute a slide, as described above. Of course, this slide can also be equipped with limit stops.

When introducing a new set of refractories, it is necessary to precisely maintain the fixed plate in a predetermined position relative to the movable plate. This is easily obtained, in accordance with the invention, by bonding the two plates. This bonding is destroyed by the means for driving the fixed plate when the casting shutter is put into operation for the first time. The predetermined relative position can also be obtained by ensuring a mechanical setting sufficiently strong to maintain the relative positions of the two plates during handling and sufficiently weak to be destroyed by the drive means (wedge in the slide, pin between the metal frames. ..).

FIG. 7 shows an alternative embodiment of the invention. In this
FIG. 7 shows an alternative embodiment of the invention. In this variant, the frame is constituted by a fixed frame 60 and by a door 62 mounted on articulated hinges 64 on the fixed frame 60. The set of refractories to be exchanged consists of a fixed refractory plate 14 and a refractory plate mobile 16. These plates have through holes arranged in alignment with one another. A manipulator 66 comprises a gripper 68, the end of which can be introduced into the holes. The gripper 68 constitutes the means which makes it possible to link the plates 14 and 16 constituting the set so as to be able to introduce and / or remove them in a single operation. It will be noted that in this embodiment the means which make it possible to link the plates together are external to the set of refractories. This is however sufficient since it is only necessary that the plates are linked together only during their handling.

Claims (16)

Set of refractory elements, in particular for a flow shutter (10), said flow shutter (10) comprising a metal frame (12) mounted on a metallurgical container (1), at least one fixed refractory plate (14) comprising at at least one orifice (14a), at least one movable refractory plate (16) comprising at least one orifice (16a), at least one collecting nozzle (42), displacement means for moving the movable plate (14) relative to the fixed plate (16) so as to control the covering of the orifice of the fixed plate by the orifice of the movable plate; pressing means (26) which allow the movable plate to be clamped against the fixed plate, characterized in that said at least one fixed refractory plate (14) and said at least one movable refractory plate (16) said at least one collecting nozzle (42) are able to be linked together so as to constitute a clearance which can be introduced and / or removed from the shutter (10) in a single operation. Game according to claim 1 characterized in that the refractory elements which constitute the game are linked together by means which allow movement of said at least one fixed refractory plate (14) relative to said at least one movable refractory plate (16) , the amplitude of this movement being sufficient for the operation of the shutter (10). Game according to one of claims 1 or 2 characterized in that said at least one fixed refractory plate (14) said at least one movable refractory plate (16) and said collecting nozzle (42) comprise metallic envelopes (38, 40) the connection between the plates being ensured by means of the envelopes (38, 40). Game according to claim 3 characterized in that the connection between said plates (14, 16) is ensured by slides fixed on said metal envelopes (38, 40). Game according to any one of claims 2 to 4 characterized in that it comprises means for locking the relative movement of said fixed refractory plate relative to said movable refractory plate in a predetermined position, in particular superimposed, these means being destroyed during the first movement of the shutter (10). Game according to claim 1 characterized in that the connection between said at least one fixed refractory plate (14) and said at least one movable refractory plate (16) is ensured by bonding, the bonding bond being destroyed by the first movement of the shutter (10). Game according to claim 1 characterized in that said plates comprise means which make it possible to maintain them in a predetermined relative position, in particular superimposed by means of connection external to the sets of refractory plates (14, 16). Game according to claim 7 characterized in that the external connecting means are constituted by a gripper manipulator (66) able to grasp and / or lock the refractory game in relative position. Method for replacing the set of refractory elements of a pouring shutter, said shutter comprising a metal frame (12) mounted on a metallurgical container (1), at least one fixed refractory plate (14) comprising at least one orifice (14a ), at least one movable refractory plate (16) comprising at least one orifice (16a), at least one collecting nozzle (42), displacement means for moving the movable plate (14) relative to the fixed plate (16) so as to control the covering of the orifice of the fixed plate by the orifice and of the movable plate; pressure means (26) which allow the movable plate to be clamped against the fixed plate, characterized in that said refractory clearance is put in place and / or removed in a single operation. Replacement method according to Claim 9, characterized in that a handling tool (66) is used comprising a gripper (68), said gripper (68) ensuring a connection of the elements of the refractory clearance at the time of installation and / or the removal of said plates. Replacement method according to any one of claims 9 or 10, characterized in that a handling tool is used to remove the used refractory set, and another handling tool to install a new refractory set so to reduce the time required to replace the plates. Replacement method according to any one of claims 9 to 11, characterized in that the used refractories are evacuated by gravity, the elements of the refractory clearance being linked only during their introduction into the obturator. Method of replacing refractory plates, characterized in that the metal envelopes (38, 40) are changed, at the same time as the set of refractories surrounding each of said plates respectively. Replacement method characterized in that the moving means (28, 44) of the movable refractory plate (16) are used to move the set of refractories to a position in which it is no longer subjected to the action of the pressure means (26) which allow the movable plate (16) to be clamped against the fixed plate (14), which frees it from any attachment to the shutter (10), so as to allow access to the handling manipulator without opening the metal frame (12) of the shutter. Replacement method according to claim 14, characterized in that a drive frame (20) of the fixed plate (14) and a drive frame (22) of the movable plate (16) are used, the frame fixed plate drive and the movable plate drive frame can be secured by means of a two-position lock (50) mounted on the drive frame (20) of the fixed plate. Replacement method according to claim 15, characterized in that the frame (20) for driving the fixed plate has a central opening into which the fixed plate (14) is inserted, and in that the drive frame (22 ) of the movable plate has a central opening into which the movable plate (16) is introduced, the central opening of the drive frame of the fixed plate and the central opening of the drive frame of the movable plate being superimposed during extracting and inserting the set of refractories.

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