EP0332490B1 - Ladle for transporting especially liquid metals - Google Patents

Abstract

The invention relates to a ladle for transporting a liquid product such as liquid metal. The ladle comprises a casing (1) with thermally-insulating walls and a cover (2), for closing the said casing, which is provided with orifices permitting achievement of the functions such as the filling, preheating and flue-venting of the ladle, it being possible for each one to be closed off by a closing-off cap. It is characterised in that the cover (2) for closing the casing (1) is provided with an orifice (14) which can be closed off by a cap (15), which is located close to the periphery of the cover and whose axis is tilted relative to the horizontal plane so as to permit skimming of all the surface of the liquid metal contained in the ladle. The invention may be used for transporting liquid metals over large distances. <IMAGE>

Description

The present invention relates to a bag for transporting a liquid product having a temperature very different from ambient temperature, such as liquid metal, of the type comprising a carcass with thermally insulating walls and a cover for closing said carcass, which is provided the filling or preheating orifice and, if necessary, a chimney orifice, each being closable by a closure cap.

Pockets of this type are already known. However, they do not allow the transport of specific metals or alloys, for example aluminum, over relatively long distances, without altering the quality of the product, in particular in the case of large volume bags. In this context, no satisfactory solution has been found to the problem of impurities assembling on the surface of the bath of liquid metal inside the pocket as well as to the problem of protecting the metal against any access of oxygen. , air and humidity.

The object of the present invention is to propose a transport pocket of the above-mentioned type which overcomes the drawbacks of known pockets.

To achieve this object, a transport pocket according to the invention is characterized in that the carcass closure cover is provided with an orifice closable by a cap, which is located at the periphery of the cover and the axis is inclined relative to the horizontal plane so as to allow skimming of the entire surface of the liquid metal contained in the pocket.

According to another advantageous characteristic of the invention, the upper edge of the carcass and the lower edge of its cover are each provided with an annular flange projecting radially outwards and in that an annular sealing device is placed between facing surfaces of these flanges and subjected to clamping forces using clamping means such as stirrups distributed regularly around said flanges.

According to another advantageous characteristic, the sealing device comprises a radially internal annular seal intended to cut off the heat and forming a barrier to the infiltration of the metal into the device and a radially external seal made of an insulating material such as silicone, facing surfaces of the flanges delimiting a chicane space in which the joints are arranged.

According to yet another advantageous characteristic, each orifice and its associated closure cap has annular flanges projecting radially outward between the faces opposite which is inserted a circular seal made of an insulating material such as silicone, by the through a number of clamping stirrups distributed regularly around said orifice.

According to yet another advantageous characteristic of the invention, the bag according to the invention comprises lifting means allowing its suspension to a handling spreader, which are fixed to the carcass.

• La figure 1 est une vue en élévation d'une poche de transport de métaux liquides selon la présente invention ;
• La figure 2 est une vue de dessus de la poche de transport selon la figure 1 ;
• La figure 3 est une vue en coupe, avec arrachement, et à plus grande échelle, selon la ligne III-III de la figure 2 ;
• La figure 4 est une vue en coupe, avec arrachement, et à plus grande échelle selon la ligne IV-IV de la figure 2, le chapeau étant dans sa position d'obturation de l'orifice ;
• La figure 5 est une vue en coupe axiale d'une poche selon l'invention équipée d'un dispositif agitateur du bain de liquide ; et
• La figure 6 est une vue avec arrachement et à plus grande échelle d'un chapeau d'obturation de l'orifice du couvercle de fermeture de la poche selon l'invention pourvu d'un dispositif de prise de température.

The invention will be better understood, and other objects, characteristics, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the drawings. annexed diagrams given solely by way of example illustrating an embodiment of the invention, and in which:

• Figure 1 is an elevational view of a liquid metal transport bag according to the present invention;
• Figure 2 is a top view of the transport bag according to Figure 1;
• Figure 3 is a sectional view, broken away, and on a larger scale, along the line III-III of Figure 2;
• Figure 4 is a sectional view, with cutaway, and on a larger scale along the line IV-IV of Figure 2, the cap being in its position for closing the orifice;
• Figure 5 is an axial sectional view of a pocket according to the invention equipped with a device for agitating the liquid bath; and
• Figure 6 is a cutaway view on a larger scale of a closure cap of the orifice of the pocket closing cover according to the invention provided with a temperature taking device.

Referring to the figures which show by way of example a pocket for transporting a liquid metal according to the invention, it can be seen that the latter comprises a part forming a carcass 1 capable of being closed by a cover 2. The base 3 of the carcass is shaped to be fixed on a transport vehicle. 4 shows four devices for suspending the bag from a lifting beam 5 of a lifting device. The fourth suspension devices are fixedly mounted on the carcass 1.

The cover 2 for closing the pocket comprises first and second orifices 7 and 8 which are offset and can be closed off respectively by caps 9 and 10 articulated at 11 and 12 to the cover. These orifices 7 and 8 are in a substantially horizontal plane, that is to say perpendicular to the longitudinal axis of the pocket.

The cover 2 is provided with a third orifice 14 closable by a pivoting cap 15 articulated at 16 to the cover 2. This orifice 14 is located near the periphery of the cover 2 and its axis is inclined relative to the horizontal plane, the part radially internal of the frame of this orifice, namely the articulation device 16 from the cap 15 to the cover 2 being located at a raised level with respect to the edge of the cover. This inclination is chosen so that it is possible to skim the surface of the liquid metal bath when the bag is filled to the optimum level before transporting the bag.

With particular reference to FIGS. 3 and 4, the sealing system for the lid 2 and the caps 9, 10 and 15 will be explained below, preventing any penetration of oxygen, air and humidity into the filled bag. of liquid metal when the cover and the caps are in their closed positions.

In FIG. 3, it can be seen that the upper edge of the carcass 1 and the lower edge of the cover 2 are respectively surrounded by annular flanges 18, 19 which protrude radially outwards and contain between their facing surfaces a device for annular seal 20. The latter includes a seal annular 21 located between the two flanges 18 and 19 on the side of the internal space of the pocket and intended to cut the heat given off by the liquid metal and to prevent the infiltration of the liquid metal into the device 20. The seal 21 has a section substantially square transverse and is advantageously formed by a braid of ceramic fibers. The sealing device 20 comprises a second radially external annular seal 22, which has the function of establishing good insulation and is advantageously made of silicone for this purpose. The two seals 21 and 22 are held laterally in place in the space between the two flanges 8 and 10 by annular elements of lateral stop 23 and 24 and of spacing 25 which are welded to the lower flange 18 secured to the carcass 1 and formed by an annular steel plate, like the flange 19. On the radially outer edge of the latter is welded by its upper edge a ring 26 coaxial with the pocket and extending in the direction of the flange 18. All of the two flanges 18, 19 and of the annular element 26 creates a baffled path making it possible to obtain, with the abutment elements 23 to 25, a labyrinth sealing device.

The two annular seals 21 and 22 are capable of being clamped between the two flanges 18 and 19 using a number of clamping brackets 28, articulated by their lower ends at 29 to articulation yokes 30 located below the lower flange 18 and integral with the latter and with the carcass 1. The other end of the stirrup 28 houses a clamping bolt device 31 which is capable of bearing on the top of the upper flange 19. The stirrups 28 are distributed regularly around the flanges 18 and 19 in an appropriate number to ensure satisfactory compression of the seals 21 and 22 with the aim of surely preventing any penetration of oxygen, of air and humidity in the internal space of the pocket, while ensuring good thermal insulation.

FIG. 4 shows the sealing device ensuring a tight closure of the orifices 7, 8 and 14 by their respective caps 11, 10 and 15. As in the case of FIG. 3, each orifice and its associated obturation cap have flanges forming necks 33, 34 between which is placed an annular insulating seal 35 of circular cross section. This seal is advantageously made of silicone. The seal is held in place laterally by two annular abutment elements 36, 37 integral with the stationary flange 33. The arrangement of the seal 35 could be reversed, in particular for the orifice 14 and the cover 15 and then be integral with the latter. The seal 35 is capable of being compressed between the flanges 33 and 34 by a number of clamping stirrups 38 distributed regularly around the orifice to be closed. Each stirrup is articulated by its lower end at 39 to articulation yokes 40 fixed to the frame of the orifice forming part of the cover 2, below the fixed flange 33. The stirrup comprises at its upper end a device with clamping bolts 41 by which it bears on the edge of the cap which carries the upper flange 34. The flanges 33 and 34 are made of steel.

Referring to FIG. 5, it can be seen that the orifice 7 allows the introduction inside the pocket of an agitating device comprising a stirring turbine represented at 43 located at a certain distance above the bottom 44 of the carcass and carried at the lower end of a rotary shaft 45 driven by a motor device not shown. At the turbine 43, an inert gas such as argon or nitrogen is ejected at 48 which is intended to produce a driving effect, by its bubbles, of impurities in direction of the surface of the liquid metal where the dirt can be skimmed through the orifice 14. The turbine 43 has the function of stirring the liquid metal. If necessary, to prevent the formation of a calm zone at the level of the walls of the carcass, a refractory deflector (not shown) is advantageously introduced through the orifice 8. The purpose of this deflector is to create appropriate turbulence inside the pocket. In order to be able to produce this effect, the orifice 8 should be placed in a suitable location relative to the location of the orifice 7. The relative arrangement of the orifice shown in FIG. 2 is particularly effective.

FIG. 6 shows a temperature taking device 49 which can be incorporated into the cover 2 or into one of the caps for closing the orifices provided therein, for example in the cap 9. The device comprises a steel cover 50, a a cone-shaped member 51 which is placed in an appropriately shaped hole which passes through the cap. This cone has a passage 56 forming a temperature orifice and into which is inserted a windscreen 52 made of a felt material, for example molded ceramic fibers. This windscreen 52 closes the temperature taking orifice but, thanks to the material constituting it, is pierced by a pyrometric rod allowing the temperature of the metal to be taken. The cover 50 of the temperature taking device can be removed from the orifice and locked therein using a mechanism comprising an arm 53 for supporting the hood, which is articulated at one end at 54, at the cap. and the other end of which is lockable using a flywheel clamping device 55, as shown in the figure.

To ensure perfect drying of the bag before each use, the carcass and the cover 2 of the bag are provided with a number of purge devices, one of which is shown at 57 in FIG. 5. The number of these devices and their distribution are chosen to ensure optimal drying. Each purge device 57 has a hole 58 which passes through the outer sheet metal layer 59 of the pocket and a member 60 for opening and closing the hole 58. Thus the moisture having passed through the internal lining 61 of the pocket, which internally covers the sheet metal layer 59, can escape to the outside.

As can be seen in the part circled on the right in FIG. 5, the pocket according to the invention is also provided with a temperature taking device 63 making it possible to determine the temperature inside the lining 61, that is to say i.e. at the interface of two constituent layer structures of the latter, namely a radially inner layer structure 64 made of a refractory material such as concrete and a radially outer layer structure 65 made of an insulating material which internally covers the outer sheet layer 59. This device can be formed by a thermocouple mounted in a suitable passage 62 passing through the outer layers 59 and 65 to the interface.

According to FIG. 5, the transport pocket is additionally equipped with a device 66 for scanning the air still in the pocket after the latter has been filled, in the space between the level of the liquid metal and the cover, by the introduction of an inert gas such as nitrogen or argon.

To this end, a passage 67 has been placed in the pocket shown by way of example, through the cover 2 by which the inert gas is introduced via a conduit 68 for connection to a gas source (not shown). The duct is provided with a valve 69 and a pressure gauge 70 as well as, if necessary, a flow meter (not shown).

The device 66 could also have to create a suppression in the space between the metal and the cover which makes it possible to further improve the protection of the metal against oxygen, air and humidity of the environment. It should be noted that the source of inert gas could be mounted on the transport vehicle.

The various constructive characteristics of the pocket of the invention which have just been described contribute to solving the problem which is the basis of the invention and which consists in proposing a pocket for transporting a liquid metal, in particular of alloys the quality of which must not be impaired during transport even over relatively long distances. The bag must have a large storage volume, for example 6 tonnes or more. Thanks to the sealing devices between the carcass 1 and its cover 2 and the orifices 7, 8 and 14 and their associated closure caps, any penetration of oxygen, air and humidity into the pocket, during transport is surely prevented. In addition, the purge devices 57 make it possible to evacuate from the internal space of the bag the moisture which could have remained in the latter following use, during a preheating and drying operation. known per se. According to the invention, this drying can be controlled and optimized using the temperature control or taking device 63, at the interface of the two layers 64 and 65 of the internal lining of the bag. Thanks to the temperature control device 63, the temperature level can be detected during the preheating and drying operation and, after reaching this level, continue the heating for an appropriate time interval ensuring the escape of any moisture through the purge devices 57, while monitoring and controlling the temperature at the inside of the pocket using a pyrometric rod introduced through an opening in the pocket cover.

Regarding the function of the orifices 7, 8 and 14, apart from their specific and non-interchangeable functions which have been described above, they are multifunctional and can if necessary all serve as filling orifices, for introducing the burner and the chimney .

It should also be noted that the fact of having fixed the attachment or suspension points 4 of the pocket only on the carcass and not at the level of the cover as is usual in the prior art, the suspension and the handling of the pocket is in no way detrimental to the sealing system of the pocket.

Claims (12)

1. Ladle for the transport of a liquid product having a temperature differing from the room temperature such as liquid metal, of the type comprising a carcase (1), with thermally insulating walls and a cover (2) for closing the said carcase (1) which is provided with openings (7, 8, 14) allowing to accomplish functions such as the filling, the preheating and of the flue of the ladle, each one of which may be closed by a closure cap (9, 10, 15), characterized in that the cover (2) for the closure of the carcase (1) is provided with an opening (14) which may be closed by a cap (15) which is located near the periphery of the cover and the axis of which is inclined with respect to the horizontal plane so as to allow a skimming of the whole surface of the liquid metal contained in the ladle.

2. Ladle according to claim 1, characterized in that the upper edge of the carcase (1) and the lower edge of its cover (2) are provided each one with an annular flange (18, 19) projecting radially outwards and in that an annular sealing device (20) is placed between the confronting surfaces of these flanges and subjected to clamping forces with the assistance of clamping means such as yokes (28) regularly distributed around the said flanges.

3. Ladle according to claim 2, characterized in that the sealing device (20) comprises a radially inner annular joint (21) adapted to cut off the heat and to form a barrier to the infiltration of the liquid metal into the device and made from a material such as a braid of ceramic fibres and advantageously with a substantially square cross-section and a radially outer joint (22) from an insulating material such as silicone, the confronting surfaces of the flanges (18, 19) advantageously defining a baffle space in which the joints (21, 22) are disposed.

4. Ladle according to one of the foregoing claims, characterized in that each opening (7, 8, 14) and its associated closure cap (9, 10, 15) exhibit annular flanges (33, 34) projecting radially outwards, between the confronting faces of which is inserted a joint (35) from an insulating material such as silicone through the medium of a number of clamping yokes (38) regularly distributed about the said opening.

5. Ladle according to one of the foregoing claims, characterized in that it comprises means (4) for the lifting and suspension from a handling device (5) which are fastened to the carcase (1).

6. Ladle according to one of the foregoing claims, characterized in that it comprises a number of drain devices (57) which are distributed on the carcase and the cover and are piercing the outer metal sheet wall (59) of the ladle to ensure the escape of the moisture contained inside of the ladle.

7. Ladle according to one of the foregoing claims, the wall of which comprises from the outside towards the inside an outer metal sheet layer (59), at least one layer of an insulating material (65) and at least one layer of a refractory material (64), characterized in that it comprises a passageway (62) extending through the external wall (59) and the adjacent insulating layer (67) substantially down to the interface of the insulating and refractory layers (65, 64) and allowing the putting in place of a member sensing the temperature at the level of the interface, such as a thermocouple.

8. Ladle according to one of the foregoing claims, characterized in that the cover (2) or one of the caps (9, 10 or 15) for closing the opening comprises a temperature pick-up device (49) comprising a thoroughfare duct which is shut by a member forming a shade (52) of a suitable felt material such as molded ceramic fibres and which may be transpierced by a temperature pick-up member such as a pyrometric rod.

9. Ladle according to one of the foregoing claims, characterized in that one of the openings (7) is adapted for the putting in place inside of the ladle of a stirring turbine (43) to the simultaneous injection of an inner gas (at 48) promoting the carrying along of the impurities at the surface of the bath of liquid metal.

10. Ladle according to claim 9, characterized in that with the opening for holding the stirring turbine (43) is associated an opening (8) disposed with respect to the holding opening (7) so that a refractory deflector inserted into the ladle through the opening (8) creates a turbulence in the bath of liquid metal stirred by the stirring turbine (43) likely to avoid the formation of a quiet zone near the wall of the carcase.

11. Ladle according to one of the foregoing claims, characterized in that it comprises a device (66) for sweeping the air contained in the ladle after the filling of the latter between the level of metal and the cover (2) with the assistance of an inner gas, this device comprising a passageway (67) extending through the wall of the ladle, advantageously of the cover (2) for the introduction of the gas into the ladle through the medium of a pipeline (68) which may be closed.

12. Ladle according to claim 11, characterized in that the sweeping device (66) serves also to create an overpressure inside of the ladle above the level of the liquid metal.

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