EP0329566B1 - Converter for the production of metal - Google Patents

Abstract

A convertor comprising a vessel (1) resting on two supports (2) by means of two diametrically opposed rotary bearing members (3) centred on the same tilting axis (15). <??>According to the invention the two bearing members for the vessel (1) consist respectively of two hoops (3,3') of fairly large diameter bearing on rollers (5) and forming an integral part of the vessel (1), each hoop (3,3') being fastened directly to the side wall of the vessel (1) along its inner edge (31); the diameter of the hoop (3) being determined so that the connection is ensured over a sufficient length. <??>The invention is applied especially to steel manufacture. <IMAGE>

Description

The subject of the invention is a new embodiment of a metal processing converter.

The converters, used in particular for the preparation and refining of steel by blowing air or oxygen into a cast iron bath, generally consist of a retort in the form of an elongated tank in which is charged a bath of liquid metal to be treated, for example cast iron.

The tank consists of a side wall, generally of revolution about an axis and limiting a treatment space closed at one end by a bottom and opening at its other end on a loading and pouring orifice, the side wall and the bottom being covered with a refractory lining.

It is known that the retort must be placed in an upright position for blowing air or oxygen and then inverted by rotation around a horizontal axis for the casting of the metal after treatment. To this end, the tank is placed between two raised fixed supports on which it rests by means of two diametrically opposite rotary support members centered on the same horizontal axis around which the tank can tilt under the action of a control means.

This type of apparatus, known since the beginning of the metallurgical industry, has obviously been the subject of numerous improvements linked to advances in the technique and the method of supporting the tank with respect to the rotary support members which define the tilting axis is particularly important because it is on it that the behavior of the tank and the supporting organs and their evolution over time depends, especially since the mass of liquid metal treated in one operation and, consequently, the dimensions and weight of the converter have become very important.

In general, the support members are subjected, on the one hand, to mechanical loads which depend on the self-weight of the tank and the refractories, on the load of cast iron and / or scrap and on the vibrations caused by the treatment. and, on the other hand, the thermal loads due to the temperature of the pig iron loaded in the tank, to the temperature given off by the blowing of air or oxygen during the preparation and to the radiation during the cleaning or emptying .

Up to now, it has therefore seemed natural to produce, in the form of very distinct members, on the one hand the treatment tank covered internally with a refractory coating so as to withstand the high temperatures due to the treatment and on the other hand its support means which generally comprise a circular belt delimiting an orifice in which the tank can be threaded, bearing on the two fixed supports, by means of pins.

The tilting movement is applied to the belt which rotates around its pins by driving the tank. To this end, the tilting torque can advantageously be applied to a crown of fairly large diameter wedged on one of the pins and whose rotation is controlled by a reduction gear (FR-A-1,550,338). Such a crown, in the form of a cylindrical ferrule centered on the tilting axis, can also be rotatably mounted on rollers so as to serve as a support member for the belt (FR-A-1257664).

The treatment function and the support and tilting function are thus ensured by separate members which can be provided accordingly, for example, the belt can be cooled by circulation of water, which is not possible in tank. On the other hand, to allow relative movements and expansions, the tank is not generally supported by the belt only by isolated support points.

Such an embodiment is, however, very heavy and expensive since the belt must support not only the weight of the tank but also the moments due to tilting. The self-weight of the belt can, moreover, be of the same order as that of the tank.

In addition, the distribution of the support forces of the retort on the belt is delicate and rarely isostatic so that differential stresses appear, the distribution of loads is disturbed and the stresses unbalanced.

In general, however, such an embodiment apparently gives satisfaction and has therefore become generalized, its drawbacks being able to be combated by various mechanical or thermal devices. But all these provisions complicate installation, operation and maintenance and increase the cost without, however, eliminating all the problems.

The subject of the invention is a new embodiment of the converter making it possible to satisfactorily resolve all of these difficulties thanks to a much simpler support mode.

The invention therefore applies, in general, to a converter of the type comprising an elongated tank placed between two raised fixed supports and constituted by a hollow side wall centered on an axis and limiting a closed treatment space to a end by a bottom, the assembly being internally covered with a refractory lining, two diametrically opposite rotary support members, taking support, respectively, on the two fixed supports and centered on the same transverse axis of tilting orthogonal to the axis of the tank, and means for controlling the tilting of the tank around the transverse axis.

According to the invention, each rotary support member of the tank comprises a piece in the shape of a large-diameter circular ferrule, on which are formed a plurality of regularly distributed notches limiting a plurality of spaced connecting blades whose ends are turned towards the tank are fixed directly to the side wall thereof along an internal connecting edge, said connecting blades being calculated so as to withstand the various forces of bending, compression and shearing, while allowing the deformations of the tank so that the use of a support belt independent of the tank is not necessary.

In general, the diameter of each ferrule may be between a quarter and a half of the diameter of the tank.

In a particularly advantageous embodiment, each rotary support member comprises a circular track formed on the external face of the ferrule and bearing on at least two rotary rollers mounted on the corresponding fixed support and spaced from one another .

To collect, under good conditions, the vertical forces, each support member preferably comprises a series of gussets placed inside the shell and associated respectively with said connecting blades, each gusset having two perpendicular sides fixed respectively on the side wall of the tank and on the internal face of the shell.

According to another advantageous arrangement, each support is provided with at least two counter-rollers for holding the ferrule, bearing on the latter on the side opposite to the support rollers. These counter-rollers can be carried by an annular frame surrounding the ferrule by bearing from the outside on the same circular track as the support rollers, at the upper part thereof. However, it is also possible to provide a second circular track on the internal face of the ferrule on which are supported counter-rollers opposite in pairs to the support rollers placed on the other side of the ferrule, all of the rollers being mounted in a frame which covers only the lower part of the shell.

According to another advantageous characteristic, the rollers and the circular tracks have rounded shapes, respectively convex and concave, cooperating with each other to compensate for misalignments, any mechanical or thermal distortions and the lateral retention of the track on the rollers. .

The invention also has the advantage of simplifying the control of the tilting of the tank by using one of the support rings as a drive ring on which a tilting mechanism acts. For this purpose, it is possible to use a circular flange fixed on its periphery on one of the support ferrules and in the center of which is fixed a control shaft centered on the tilting axis and connected by a reducing mechanism to at least one tilt control motor.

It is also possible to provide directly on one of the support ferrules or on an extension thereof, a toothed ring meshing with one or more pinions driven in rotation.

According to an arrangement known in other applications, each pinion could be mounted in a casing carrying rollers rolling on circular tracks adjacent to the ring gear to maintain the meshing of the pinion with the latter.

In this way, as on the non-motorized side, the interior of the ferrule is entirely freed for the passage of piping of fluids useful for the metallurgical process.

• La figure 1 est une vue d'ensemble en élévation d'un convertisseur selon l'invention, en coupe par le plan passant par l'axe de la cornue et l'axe transversal de basculement.
• La figure 2 et la figure 3 sont des vues de face des deux organes d'appui placés de part et d'autre de la cornue, respectivement suivant les flèches F1 et F2 de la figure 1.
• La figure 4 est une vue de détail représentant une virole d'appui en coupe par un plan horizontal selon la ligne AA de la figure 1.
• La figure 5 est une vue partielle en élévation de la cornue représentant un autre mode de réalisation de la virole d'appui.
• La figure 6 est une vue en coupe de la virole par un plan perpendiculaire à son axe selon la ligne BB de la figure 5.
• La figure 7 est une vue d'ensemble en élévation représentant une variante de réalisation de l'invention.
• La figure 8 est une vue de face de la virole d'appui suivant la ligne F3 de la figure 7.
• La figure 9 est une vue partielle en élévation représentant une variante de réalisation du mécanisme de basculement.

Other characteristics of the invention will appear in the following description of certain embodiments given by way of example and shown in the accompanying drawings.

• Figure 1 is an overall elevational view of a converter according to the invention, in section through the plane passing through the axis of the retort and the transverse axis of tilting.
• FIG. 2 and FIG. 3 are front views of the two support members placed on either side of the retort, respectively according to the arrows F1 and F2 of FIG. 1.
• FIG. 4 is a detail view showing a support ring in section through a horizontal plane along the line AA in FIG. 1.
• Figure 5 is a partial elevational view of the retort showing another embodiment of the support ring.
• FIG. 6 is a sectional view of the ferrule by a plane perpendicular to its axis along the line BB in FIG. 5.
• Figure 7 is an overall elevational view showing an alternative embodiment of the invention.
• FIG. 8 is a front view of the support ring along line F3 in FIG. 7.
• Figure 9 is a partial elevational view showing an alternative embodiment of the tilting mechanism.

In Figure 1, there is shown, in elevation, the assembly of a converter comprising, generally, a retort 1 placed between two supports 2 and 2 ′ and resting on the latter by means of two members rotary support 30 and 30 diam diametrically opposite and centered on a horizontal axis (15) around which the tank can rotate, under the action of a mechanism 4 for tilting control, so as to be first directed towards the high for the loading of the liquid metal and, if necessary, of the scrap, as well as for the processing of processing, then inclined downwards for the casting of the metal.

The tank 1 is constituted by a side wall 11 of revolution about an axis 10 orthogonal to the tilting axis 15, closed at one end by a bottom 12 and opening at its other end on an orifice 13. The wall lateral 11 has, generally, a cylindrical shape in its central part and tightens at its open end so as to limit the orifice 13. The whole of the lateral wall 11 and of the bottom 12 is covered internally by a refractory lining 14.

Each support member 30, 30 ′ consists essentially of a cylindrical shell 3, 3 ′, centered on the transverse axis 15 and fixed directly to the side wall 11 of the tank 1.

It can therefore be seen that, according to the essential characteristic of the invention, the two support ferrules 3 and 3 ′ form an integral part of the tank 1 whose side wall 11 is entirely free between the two ferrules 3, 3 ′ since no support belt is necessary.

Each ferrule 3, 3 ′ is fixed to the side wall 11 of the tank, along its circular edge 31 turned towards the latter and the diameter of the ferrule must therefore be determined so that the connection is provided over a length sufficient for absorb the stresses resulting from the forces applied in service and from differential expansions. Each ferrule will therefore have a much larger diameter than that of conventional pins and which may for example be of the order of half the diameter of the tank.

Each support ring 3, 3 ′ rests, along its external face 36, on a pair of support rollers 5 rotatably mounted each around an axis 50 parallel to the transverse axis 15 on a frame 51 fixed itself- even at the top of the support block 2, 2 ′.

As seen in Figures 2 and 3, the two rollers 5 are spaced from each other, on either side of the median plane P1 of the tank passing through the axis 10 of the tank and the tilting axis 15, so as to provide a good seat.

To collect the support forces under good conditions, the ferrule 3 is mounted on a series of gussets 32 directed along radial planes passing through the axis 15, distributed regularly around this axis and comprising two perpendicular sides fixed respectively on the internal face 33 of the shell 3 and on the side wall 11.

As seen in Figure 4, which is a sectional view through a horizontal plane, the side wall 11 of the tank is fully exposed on its two faces 17 placed between the two support rings 3, 3 ′, c ' that is, in fact, over most of its periphery. On the other hand, in the arrangements used until now, the side wall 11 was completely surrounded by the support belt which constituted, with the fasteners of the tank, screens capable of impeding the ventilation of the sheet of the tank and that of the belt. In the arrangement according to the invention, on the contrary, most of the tank can be simply cooled by natural circulation.

Of course, it is not possible to avoid the relative expansions between the wall 11 of the tank and the support rings, but it is possible to calculate these stresses by simple methods and to consequently determine the length and the embodiment of the circular connection between each ferrule and the side wall.

In addition, to allow the relative expansions of the side wall 11 relative to the shell 3, the latter is advantageously provided with notches 34 separated from each other and regularly distributed along the shell 3 on the side facing the wall. lateral 11, the ferrule 3 being therefore connected to the wall 11 only by spaced blades 35 left between the notches 34 and by the gussets 32 which are placed in the center of the blades 35.

The connecting edge 31 of the ferrule 3 with the side wall of the tank is then formed by the ends of the blades 35 facing the tank. Of course, the diameter of the ferrule 3, as well as the dimension and the number of the notches 34 must be determined so that, in total, the connection with the side wall (11) is ensured over a sufficient length.

The external face of each ferrule 3 therefore constitutes a circular running track on the two support rollers 5, which can advantageously be constituted by a bandage 36 threaded or welded on the ferrule 3.

To maintain each ferrule 3 on the pair of support rollers 5, the latter are associated with a pair of counter-rollers 52 resting on the ferrule on the opposite side. For example, in the embodiment shown in Figure 2, the rollers 5 are mounted on a frame 51 of annular shape with clearance surrounding the ferrule 3 and at the top of which are mounted the counter-rollers 52, each rotating around d 'an axis parallel to the transverse axis 15 and bearing on the same circular track as the support rollers 5, formed by the tire 36. These rollers are applied with a controlled force so as to avoid vibrations, in particular during the phase of elaboration.

Preferably, the rollers are provided with a convex side wall and the external face 37 of the tire 36 has a corresponding concave shape, which makes it possible to center the rollers 5 and 52 on the track 36 as well as a good distribution. loads over the entire surface of the roller even when the deformations of the tank due to the stresses supported cause a slight misalignment of the ferrules 3, the axis 15 then being slightly curved.

The means 4 for controlling the tilting of the tank comprises one or more motors associated with a reduction mechanism 42. The use, according to the invention, of circular support members of relatively large diameter, simplifies the control. Indeed, the movement can be transmitted directly to the shell 3 of one of the support members 30 by means of a flange 43 fixed on the circular edge 38 of the shell on the side opposite to the tank 1. The reduction mechanism 42 can, for example, be simply mounted in overhang on a control shaft 44 integral with the flange 43 and centered on the axis 15.

Preferably, the flange 43 is held laterally between two pairs of rollers 53 mounted on the chassis 51 for supporting the rollers 5.

To ensure the free deformation of all the elements under the action of the mechanical and thermal stresses supported, the second rotary support member, placed on the side opposite to the control mechanism 4, is arranged so as to be able to move slightly by compared to these supports. In particular, the support rollers 5 ′ and retaining rollers 52 ′ of the shell 3 ′, shown in FIG. 2, can be slidably mounted on their axes so as to move laterally in the event of an increase in the diameter of the tank. On the other hand, as can be seen in FIG. 2, the annular frame 51 ′ on which the rollers 5 ′ and the counter-rollers 52 ′ are mounted, is articulated around a horizontal axis 21 on a yoke 22 fixed on the upper part of the support frame 2 ′. The possibility of the chassis pivoting is limited by springs which are not shown or else by a torsion bar which distributes the loads on the two rollers.

The invention lends itself to different embodiments. For example, in FIGS. 1 and 4, the support ferrules 3 and 3 ′ are molded parts made in one piece with the gussets 32 and the corresponding part 16 of the side wall 11 of the tank which is made up of a portion of cylindrical wall limited by a circular edge of diameter a little larger than that of the shell 3 and which is welded along a circular orifice of the same diameter formed on the side of the wall 11. In this case, the molded part 3 is calculated to resist the forces exerted and the circumference of the circular part 16 must be sufficient for the welded connection with the wall 11 to absorb the stresses.

In Figure 5, there is shown a mechanically welded embodiment which allows in particular to produce the side wall 11 of the tank in a homogeneous manner. The ferrule 3 is then a simple circular sheet welded to the wall 11 along its internal edge 31. We can then give greater possibility of deformation to the ferrule 3 by giving it a greater width, which leads to lengthen the connecting blades 35 and increase the section of the notches 34, the bandages 36 then being further apart from the side wall 11 than in the previous embodiment. The elongation of the connecting blades 35 increases the flexibility of these and, consequently, the capacity of adaptation of the shape of the shell to the stresses supported. Likewise, the T-section assemblies formed by each blade 35 associated with a gusset 32, as shown in FIG. 6, are relatively independent of each other and can follow the deformations of the shell 3.

In another embodiment shown in FIGS. 7 and 8, the support for the support rings 3 and 3 ′ is produced in a more compact manner. In fact, the support rollers 5 are each associated with a counter-roller 54 placed immediately on the other side of the shell 3, that is to say on the internal face 37 thereof. The two pairs of rollers 5 and 54 can then be mounted on a chassis 55 of reduced dimensions which simply covers the lower part of the ferrule 3.

As in the previously described embodiment, the chassis 55 for supporting the rollers placed on the side of the tilting mechanism is fixed and also carries guide rollers 53 mounted to rotate on axes directed radially and bearing on either side a side wall 43 ′ which, in this case, has an annular shape so as to allow the counter-rollers 54 to pass; the flange 43 connected to the drive mechanism 4 is then set back and fixed on the internal face 37 of the ferrule 31.

On the side opposite the mechanism, the support rollers 5 ′ and the counter rollers 54 ′ are advantageously mounted to slide axially on the chassis 51 ′ and the latter, as described above with reference to FIG. 2, is itself even mounted pivoting about a horizontal axis 21 ′ on a yoke 22 ′ fixed on the support mass 2 ′.

In FIG. 9, another particularly advantageous embodiment of the tilting mechanism is shown diagrammatically. In this case, a toothed ring 45 is applied directly to one of the support rings 3, or to an extension 40 thereof, to which the tilting control movement is directly applied, by means of one or more several pinions driven in rotation.

As shown in FIG. 9, it is advantageous to use two diametrically opposite pinions 6, each mounted in a casing 61 carried by one or more pairs of rollers 62 rolling on a track 63 formed on the internal face of the extension 40 of the ferrule .

The two diametrically opposed casings 61 bear on a torsion bar 64 perpendicular to the plane of the figure, fixed on the support block 2 and carrying at its ends two keyed cranks 65, each connected to the corresponding casing 61 by an articulated connecting rod 66 at its ends.

The two pinions can be driven by the same motor, for example by means of reducers mounted on each of the casings 61.

Other drive modes are conceivable, for example that which is the subject of French Patent No. 1,550,338 and which includes two spaced apart gears mounted in a floating casing.

This arrangement makes it possible, on the one hand, to apply the tilting torque on a large circle, by reducing the shear stresses and, on the other hand, to release the entire interior of the shell, as on the non-motorized side, to pass there the various piping of fluids useful to the process.

Of course, the invention is not limited to the details of the different embodiments which have just been described by way of example, other variants which can still be imagined, without departing from the protective framework defined by the claims.

Thus other support systems or other known mechanisms for controlling the tilting of the tank, for example by means of several motors, could be adapted to the invention by providing their own advantages.

In summary, the invention has many advantages.

The removal of the belt simplifies construction, lightens the whole and allows better cooling of the tank which is no longer hidden and enclosed under poorly ventilated covers.

The large diameter of the tire formed by each ferrule makes it possible to reduce and distribute the support and tilting forces over a larger portion of sheet metal than in conventional systems. In addition, the possibility of slight deformation of the support ferrules, and in particular the connection to the retort by relatively flexible blades calculated so as to withstand the various bending, compression and shear forces, allows the axial expansion to be left free and diametral of the tank under the effect of thermal stresses.

Unlike the conventional embodiments using an independent belt, the tank can be supported isostatically since it is supported only by two support members having a certain possibility of adaptation to the distribution of loads.

In addition, the use of simple rollers to support the bandages is less expensive and easier to maintain than the bearings used hermetically to support the pins of the pockets.

Finally, the large diameter of the support ring allows a wide passage for the various fluid pipes necessary for metallurgical processes to be left free.

Claims (14)

1. Converter, comprising:

― an elongate tank having a hollow side face (11) centred on an axis (10) located in a vertical plane and delimiting a treatment space closed at one end by a base (12), the side wall (11) and the base (12) being covered by a refractory lining (14),

― two elevated stationary stands (2) (2′) located on either side of the tank,

― two diametrically opposed members (30, 30′), for rotary bearing of the tank (1), diametrically opposed, respectively bearing on the two stationary stands (2) (2′) and centred on a transverse axis (15) of tilting perpendicular to the axis of the tank (1),

― and means (4) for controlling tilting of the tank (1) about the transverse axis (15), characterized in that each rotary bearing member (30) (30′) of the tank comprises an element in the shape of a circular hoop (3, 3′) on which there are arranged a plurality of evenly distributed recesses (34) delimiting a plurality of spaced connection tongues (35) whereof the ends facing the tank are secured directly on the side wall (11) of the latter along an inner connection edge (31), said connection tongues (35) being designed to withstand the various bending, compressing and shearing stresses, while allowing deformations of the tank, such that the use of a support belt independent of the tank is not necessary.

2. Converter according to Claim 1, characterized in that each rotary bearing member (30, 30′) comprises a circular track (36) arranged on the outer face of the hoop (3) and bearing on at least two rotary rollers (5) mounted on the corresponding fixed support (2) (2′) and spaced from one another.

3. Converter according to one of Claims 1 and 2, characterized in that each bearing member (30, 30′) comprises a number of gussets (32) placed inside the hoop (3) and associated respectively with the said connection tongues (35), each gusset (32) comprising two perpendicular sides secured respectively on the side wall (11) of the tank and on the inner face (33) of the connection tongue (35).

4. Converter according to Claim 2, characterized in that each support (2) (2′) is equipped with at least two counter-rollers (52, 54) for holding the hoop (3), bearing on the latter on the side opposite the support rollers (5).

5. Converter according to Claim 4, characterized in that the support rollers (5) and the counter-rollers for holding (52) are supported by an annular frame (51) surrounding the hoop (3), and in that the counter-rollers (52) bear from the outside on the same circular track (36) as the support rollers (5), on the upper part of the track.

6. Converter according to Claim 4, characterized in that the support rollers (5) and the counter-rollers for holding (54) are placed in a frame (55) covering the lower part of the hoop (3), and in that the counter-rollers (54) bear from the inside on a second circular track (37) arranged on the inner face (33) of the hoop (3).

7. Converter according to one of Claims 5 and 6, characterized in that the rollers (5, 52, 54) and the circular track or tracks (36) (37) are of a rounded shape, respectively convex and concave, cooperating with one another for lateral holding of the track (36) (37) on the rollers (5) (52) (54).

8. Converter according to one of Claims 2 to 7, characterized in that the frame (51′) carrying the support rollers (5′) of at least one of the hoops (3′) is pivotally mounted on the corresponding stationary stand (2′) about an axis parallel to the axis (15) of tilting of the tank (1).

9. Converter according to one of the preceding claims, characterized in that the means (4) for controlling tilting have a mechanism (42, 43) acting directly on one of the hoops (3).

10. Converter according to Claim 9, characterized in that the means (4) for controlling tilting have a circular flange (43) secured on its periphery on one of the hoops (3) and in the centre of which there is secured a control shaft (44) centred on the axis (15) of tilting and connected by a reduction mechanism (42) to at least one motor (41) for controlling tilting.

11. Converter according to Claim 9, characterized in that the means (4) for controlling tilting have a toothed ring (45) arranged directly along one of the hoops (3) and on which there meshes at least one pinion (6) driven by a motor for controlling tilting.

12. Converter according to Claim 11, characterized in that each drive pinion (6) is floatably mounted in a housing (61) equipped with means for holding the said pinion (6) in contact with the toothed ring (45).

13. Converter according to Claim 12, characterized in that the means (4) for controlling tilting have two pinions (6), each mounted in an individual housing (61) and placed symmetrically on either side of the vertical plane passing through the axis of tilting, and in that both housings (61) bear separately on one and the same torsion rod (64) which is perpendicular to the vertical plane of symmetry and on which there are wedged two cranks (65), each connected to one of the housings (61) by a connecting rod (66) articulated on the housing (61) and on the end of the crank (65).

14. Converter according to one of Claims 9 to 13, characterized in that the hoop (3) connected to the tilting mechanism (4) is associated with stationary rollers (5) (52, 54), whereas the opposite hoop (3′) is associated with rollers (5′) (52′; 54′) slidably mounted on their frame (51′) according to the direction of the axis (15) of tilting so as to follow the expansions of the tank (1) and of the elements associated therewith.

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