MXPA96006255A - Charging device for fusing oven with girato conduit - Google Patents

Abstract

The present invention relates to a charging device for a melting furnace with a rotating duct consisting of a supporting structure 22 by suspending the melting furnace 10, a mounting flange 18 fixed rigidly to the melting furnace 10, a batch hopper 26 and 28 supported by the support structure 22, a conductive housing 30 for the conduit 32, which is connected in a sealed manner at one end to the batch hopper 26 and 28, and at the other end to the mounting flange 18, and at least one bearing ring of diameter 40 mounted in the housing 30 to support the conduit 32 with the ring 40. In order to increase the working life of the bearing ring 40, at least one deformable connecting element 70 is incorporated in the chain of rigid elements connecting the mounting flange 18 with the roller ring 40, in a form such that the deformation transmission of the mounting flange 18 to the bearing ring is largely prevented.

Description

CHARGING DEVICE FOR FUSING OVEN WITH ROTATING CONDUIT The present invention relates to a loading device for a melting furnace with a rotating duct, consisting of a support structure suspended to the melting furnace, a batch hopper supported by this support structure, a conductive housing for the duct, the which is connected * // of a form sealed on one side to the batch hopper and on the other side to a mounting flange to be rigidly fixed to the melting furnace, and at least one large diameter bearing ring mounted on the housing for supporting said rotating conduit.

BACKGROUND OF THE INVENTION Devices of this type are described, for example, in documents U5-A-3,693,812; US-A-3,880,302; US-fi- 3,814,403; US-A-4, 941, 792 and US-FL-5, 022, 806. In these devices, the conduit is suspended in a rotating cage, which is supported in the housing by means of a bearing ring of wide diameter . The rotating cage defines the lower part of an axial flow channel connecting the batch hopper with the conduit, and the wide diameter bearing ring surrounds this axial flow channel on the outside. The bearing ring is designed to absorb a large axial exertion and a large tilt movement. This consists of two coaxial rings connected by rolling elements. One of the two rings is fixed rigidly to the rotating cage, while the other ring is rigidly fixed to a support plate incorporated in the housing. The housing itself has a lower flange by means of which it is rigidly supported on the mounting flange fixed to the melting furnace. The batch hopper is connected in a form sealed to the housing, either rigidly or through the intermediation of an expansion joint. In summary, in the known devices, the weight of the conduit is rigidly transmitted through the support plate and the housing towards the mounting flange of the. melting furnace. Many charging devices equipped with a suspension for the duct of this type have been in service in blast furnaces for more than 20 years. The wide diameter bearing ring is the most reliable method known to provide the rotating suspension for the conduit in the housing. Although this type of suspension for the. Rotating duct provides complete satisfaction, should be signaled in any way that the work life of the. Large diameter bearing ring achieved in practice is substantially less than the working life that can be expected according to the calculations. This phenomenon has been known for at least 10 years, but someone skilled in the art could not explain until now why in practice the bearing ring has to be replaced earlier than predicted by the calculations. The main problem to which the present invention relates is that of increasing the working life of the bearing ring in a device of the type described above. These problems find a solution in so -, except for a deformable joining element, which is incorporated in the chain of rigid elements mechanically connecting to the mounting flange, rigidly fixed to the melting furnace, with the bearing ring that supports the rotating conduit, in such a way that a transmission of the deformations of said mounting flange to said bearing ring is largely avoided. A merit of the present invention is the understanding that the mounting flange rigidly fixed to the melting furnace is subjected to asymmetric deformations, which affect the working life of the bearing ring. These distortions of the mounting flange of the melting furnace are due, on the one hand, to the internal pressure prevailing in the melting furnace and, on the other, to the thermal expansions of the melting furnace. Its asymmetry is probably due to the fact that the head of the melting furnace, to which the mounting flange is rigidly fixed, is a non-symmetrical structure having, for example, several wide local openings. In this sequence, this head is asymmetrically deformed under the combined effect of internal pressure and tenements of thermal origin. Moreover, this head is not necessarily uniformly heated. In fact, the internal refractory lining may be thinner in certain places, which naturally produces an asymmetric heating of the head and therefore, an asymmetrical thermal stress field in the head wall. In short, the head is subjected to asymmetrical deformations that necessarily create asymmetric deformations of the mounting flange attached to the head. In devices according to the present state of the art, these asymmetrical deformations of the mounting flange are transmitted through a chain of more or less rigid elements from the housing to the bearing ring. The latter is consequently subject to asymmetric stress and stretching fields, which particularly affect its circular shape and flat character. The result of this is a faster wear and therefore a reduction in its working life, even in some cases a complete immobilization of the bearing ring long before it has reached the end of its theoretically accessible working life.

BRIEF DESCRIPTION OF THE INVENTION In the device according to the invention, the deformable joining element incorporated in the rigid chain of elements connecting to the mounting flange of the melting furnace with the bearing ring supporting the rotating conduit, absorbs a large proportion of the asymmetrical deformations of the mounting flange before these deformations can alter the geometry of the bearing ring. In a first advantageous embodiment, the deformable connection element is connected between a mounting plate and an outer cover of the housing. The bearing ring is fixed to this mounting plate and the outer cover of the housing is fixed directly to the mounting flange attached to the melting furnace. The deformations of this flange are often absorbed by the deformable joining element. The absorption effect obtained is improved if its support plate is equipped with reinforcements which give it a rigidity much greater than that of the deformable element. In a second advantageous embodiment of the invention, the deformable joining element is formed by a first expansion joint connecting the housing including said ring of a sealed form to the mounting flange of the oven, while allowing relative displacements between the housing and the mounting flange of the melting furnace. The < ? Locking is subsequently supported either directly by a rigid support structure or by the batch hopper. The latter is directly or indirectly supported by a rigid support structure. Any rigid connection between the mounting flange and the housing supporting the bearing ring is therefore eliminated. In a third advantageous embodiment, the deformable connecting element is directly connected between a plate of "Mounting incorporated in the housing and the bearing ring. This solution naturally provides the best protection of the bearing ring, since the deformations of the support plate are themselves absorbed as well. In the first and third embodiments, the deformable link element is preferably a ring whose annular wall defines a deformable loop. In a fourth advantageous embodiment, the deformable connecting element according to the invention directly supports the housing in the mounting flange. This solution differs from the first embodiment described above in that the deformable joint element is capable of transmitting the weight of the housing / conduit assembly directly towards the mounting flange of the melting furnace, while the expansion joint in the The first embodiment is only used to connect the housing in a sealed manner to the mounting flange of the melting furnace and is in no way related to the weight absorption of the housing / duct assembly. Other advantages and features of the invention will be derived from the detailed description of several preferred embodiments of the invention, and from representations of these preferred embodiments in the included drawings, in which: Figure 1 is an elevation drawn partly in the form of a cross-section, of a melting furnace equipped with a first embodiment of the loading device with rotating duct according to the invention; Figure 2 represents, in a similar view, a variant of the embodiment of the device according to Figure 1; Figure 3 represents a cross section through a vertical plane of a conductive housing for a rotating conduit forming part of a second embodiment of the loading device with rotating conduit according to the invention; Figure 4 shows a cross section through a vertical plane of a conductive housing for a rotating conduit forming part of a third embodiment of the loading device with rotating conduit according to the invention; Figure 5 shows a cross section through a vertical plane of a conductive housing for a rotating conduit forming part of a fourth mode of the loading device with rotary conduit in accordance with the invention; Figure 6 represents a detail of a deformable joining element of Figure 6.

DETAILED DESCRIPTION OF THE INVENTION Referring first to Figure 1, it will be noted that reference number 10 is used to indicate a melting furnace "~, in its totality This can be, for example, a blast furnace, but it can also be another type of furnace, which is equipped with a rotating duct The melting furnace represented consists of a cylindrical body 12 and a terminal head 14. This end head 14 incorporates a loading opening 16, which is surrounded by a mounting flange 18, hereinafter called the mounting flange 18 of the melting furnace 10. This mounting flange 18 is fixed rigidly. at the head 14 and is therefore exposed to all deformations of the latter.The reference numeral 20 is used to indicate a loading device with a rotating duct in its entirety, the latter consisting, first of all, of a structure of support 22 suspending the head 14 of the melting furnace, and which rests, for example, in the body 12 of the melting furnace In some cases, the melting furnace is, however, surrounded by a supporting structure in dependent, called a square tower, and support structure 22 will be "supported by this square tower. From the tip to the base of Figure 1, it is possible to distinguish: A fixed or rotating hopper 24 that receives the loading material; A batch hopper 26, which can be sealed at one end with respect to the hopper 24 and at the other end with respect to the oven 10; A system 28 for weighting the loading material outward, which is very often an independent element positioned below the batch hopper 26 but which, to simplify the terminology, is considered in the present description as forming part of the batch hopper 26; A driver housing 30; and A duct 32, which can rotate about the vertical axis of the melting furnace 10 and whose angle of inclination with respect to the vertical can, very often, be varied. The loading material flows from the batch hopper 26 through the weighting system 28 and the housing 30 to the rotating duct 32. The latter distributes the loading material on the loading surface indicated by the reference number 34. The housing 30 includes the means of suspension for the conduit and the means for driving the latter. Different types of means for suspending and driving conduit 32 are described in detail in the documents cited in the introductory section of the present disclosure. Using Figure 3, only a brief description will be given herein of a possible modality of these means for suspending and driving the conduit. In this way, referring to Figure 3, it can be seen that the conduit 32 is supported by a rotating cage 36 through the intermediation of two lateral pivots 38 'and 38. These lateral pivots 38' and 38"define a horizontal pivot axis for conduit 32 around the , which the angle of inclination of the conduit with respect to the vertical can be varied. The rotating cage 36 forms the lower part of the feed channel 39, which is coaxial with the axis of the furnace 10. This cage 36 is supported in the housing 30 by means of a wide-diameter bearing ring 40, which surrounds the feed channel 39 and defines the vertical axis of rotation of the cage 36. This bearing ring 40 is an attempted and tested element for the '* "rotating suspension of the conduit 32. It consists of an inner ring 42 and an outer ring 44, which are connected through shaped roller elements 46 such that they can withstand large axial loads and large tilting movements. the outer ring 44 supports the rotary cage 36, while the inner ring 42 is fixed to a support plate 48 of the housing 30. The outer ring 44 then supports a toothed gear 50, which interacts with a first pinion wheel (not shown) of a conductive mechanism (not shown) for rotating the jig 36 and consequently the duct 32 around the axis of the melting furnace 10. A pivoting mechanism it makes it possible for the angle of inclination of the conduit 32 to change when it is rotating. This mechanism very often consists of a second wide-diameter bearing ring 52, the inner ring 54 of which is fixed to the support plate 48. The outer ring 56 of this second bearing ring is equipped with a toothed gear 58 which interacts with a second pinion wheel (not shown) of a driving mechanism. This conductive mechanism is capable of giving the outer ring 56 a rotary movement, which may have a variable angular phase difference with respect to the rotational movement of the cage 36. A mechanism 60, mechanically connected between this outer ring 56 and at least one of the pivots 38 ', 38", make it possible for this difference in angular phase or phase deviation to become a pivot of the conduit on the two pivots 38', 38". Such pivoting mechanisms are described in more detail in the documents mentioned in the introduction to the present description. According to the present invention, at least one deformable connecting element is incorporated in the rigid chain of elements mechanically connecting to the bearing ring 40 supporting the rotary conduit 32 towards the mounting flange 18 of the melting furnace, in such form that a rigid transmission of deformations between the mounting flange '-? 8 and the bearing ring 40 is avoided. Figures 1 to 5 show several advantageous embodiments of the invention. According to the embodiment of Figure 1, an expansion joint 70 is connected between the flange 18 of the head 14 and the coupling flange 18 'of the housing 30. This expansion joint 70, for example a bellows expansion joint metallic, it guarantees the seal between the housing 30 and the melting furnace 10, while allowing a relative displacement of the two flanges 18 and 18 '. The housing 30 is supported by the assembly consisting of the batch hopper 26 and the weighting system 28. This assembly 26/28 is in turn supported as described above, by the support structure 22. The expansion joint 70 it therefore has to complete a sealing function and must in no way support the weight of the assembly consisting of the housing 30 and the conduit 32. It will be thus appreciated that in this embodiment, the head 14 can be asymmetrically deformed, example through the effect of an asymmetric temperature field or the internal pressures acting on the head, without these deformations affecting the housing 30. The bearing ring 40 incorporated in the housing 30 is consequently protected from the stresses induced by the Asymmetric deformations of the head 14. The device according to Figure 2 is distinguished from the device of Figure 1 by the fact that the housing 30 is directly supported by the structure "¿* 3 support 22. A second expansion joint 72 is connected between the batch hopper assembly 26 / block system 28 and the housing 30. This embodiment has the advantage that the housing 30, which is generally hotter than the batch hopper 26, 28 is capable of expanding almost freely at both ends. Furthermore, this second expansion joint is recommended if a continuous weighting of the batch hopper is required, using weighting cells incorporated in the hopper supports 26 in the support structure 22. Figure 3 shows a preferred embodiment of the invention, in which the deformable link element is incorporated in it. housing 30. This deformable joining element consists, more precisely, of a deformable ring 80 connected between the support plate 48 of the housing and an outer cover 82 of the housing 30. This modified housing 30 can be rigidly mounted on the mounting flange 18. of the melting furnace 10. Indeed, the deformations of this flange 18 affect the wall 82 of the housing 30, but have little or no effect on the support plate 48. It will be noted that the latter is advantageously reinforced by boxes 84, which increase its rigidity . Indeed, the greater the stiffness of the support plate 48 compared with that of the deformable ring 80, the more deformation of the cover 82 will be absorbed by the deformable ring. A high rigidity of the support plate 48 thus amplifies the effect of the deformation of the deformable ring 80, and thus ensures that the support plate 48 is not deformed either in its plain or in the direction In conclusion, a deformation of the head 14 is induced in the ring 42 of the bearing ring 40, which is fixed to the support plate 48, hardly affecting any deformation the circular shape and flat character of this ring 42. /, The deformable ring 80 is, for example, a ring having an open section in the form of a U. One of the arms then forms a flange fixed, by welding for example, to the wall 82.; while the other arm forms a flange fixed, by welding for example, to the support plate 48. The ring 80 is, as previously noted, sized in such a way that it is much less rigid than the support plate 48. As As a result of this, the deformations of the wall 82 produce a deformation of the U-shaped section of the ring 80 and do not affect the shape of the plate 48. Figure 4 also shows an embodiment in which the deformable connecting element is incorporated in the housing 30. In this embodiment, the outer cover of the housing 30 and the support plate 48 are more or less rigidly assembled. On the other hand, between the support plate 48 and the bearing ring 40, a deformable sleeve 90 is connected. The latter absorbs any possible deformation of the support plate 48 without transmitting preciable stresses to the bearing ring 40. The modified housing of Figure 4 itself can also be rigidly mounted on the flange 18 of the head 14. Figure 5 shows an embodiment of a deformable connecting element 100, which can be incorporated between the housing 30 and the head 14, and which has the special feature of being able to transmit the weight of the housing assembly 30 / cond ict 32 towards the head 14. The deformable element 100 consists of? n lower flange 102, fixed to the head 14, and? n mounting flange 104 supporting the housing 30. The two flanges 102 and 104 are connected by a deformable metal wall 106, which forms a loop opening inwards. It will be noted that this loop preferably has the shape of a lyre. The metallic wall 106 is dimensioned such that it is capable of transmitting the weight of the housing assembly 30 / conduit 32 from the mounting flange 104 to the lower flange 102, while allowing a relatively horizontal and / or vertical displacement of the doe. flanges 102 and 104. However, to prevent the relative movements of the two flanges 102 and 104 from becoming very large, which could cause a plastic deformation of the metal wall 106, stops 108 and 110 have been provided. The stops 108 they largely prevent a compression of the deformable element 100. On the other hand, the elements 110 largely prevent an extension and broadly a relatively horizontal displacement of the flanges 102 and 104. It should be noted that the tension bars 110 are primarily intended to broadly prevent an axial extension of the loop formed by the wall 106 through the effect of internal pressure in the furnace. (antecedent effect). Figure 6 shows in detail? A preferred embodiment of the deformable element 100. It can be seen that the loop formed by the wall 106 is completely filled with a material 112. This is an insulating and compressible material, a mineral wool, for example. An annular screen 114 closes the opening of the loop, without upsetting the deformation of the latter. This embodiment of the deformable element 100 has the advantage that the deformable wall 106 is protected from excessive heat, which could have damaging effects on its elastic properties. Still, filling the cavity inside the loop with non-compressible material that could trap the deformation of the wall 106 is discarded. It will be appreciated by one skilled in the art that two or more of the proposed embodiments may be combined in a loading device with a rotating duct for a melting furnace, in order that they mutually support each other in their absorption effects. deformation of the head 14. In this way, it is possible, for example, to combine the eolution of figure 3 with the solution of figures 2 or 5, or the solution of figure 4 with all the other solutions.

Claims (12)

NOVELTY OF THE INVENTION CLAIMS

1. - A loading device for melting furnace with rotating duct, consisting of a supporting structure

22 suspending to the melting furnace 10, a mounting flange 18 to be rigidly fixed to the melting furnace, a batch hopper 26 and 28 supported by the supporting structure 22, a conductive housing 30 for the conduit 32, which is connected in sealed form at one end to the batch hopper 26 and 28 and at the other end to said mounting flange 18; at least one wide-diameter bearing ring 40 mounted in the housing 30 and supporting said rotary conduit 32, said ring 40 being mechanically connected to said mounting flange 18 by means of a chain of rigid elements, characterized in that at least one deformable joining element 70, 80, 90, 100 incorporated in said chain of rigid elements between said mounting flange 18 and said bearing ring 40, supports the rotary conduit 32, in such a way that a rigid transmission of deformations of said mounting flange 18 to said bearing ring 40.

2. A device according to claim 1, further characterized in that said housing 30 consists of an outer cover 82 connected in a pellet between said mounting flange 18 and said hopper. batch 26 and 28 and a mounting plate 48 with high rigidity on which said mounting plate 48 is mounted on said cover 8 2.

A device according to claim 2, further characterized in that said deformable connecting element 80 has a U-shaped section.

4. A device in accordance with the claims 2 or 3, further characterized in that said mounting plate 48 includes reinforcements 84 that increase its rigidity.

5. A device according to claim 1, further characterized in that said deformable joining element consists of a first expansion joint 70 connecting said housing 30 in a sealed form to said mounting flange 18, while allowing the relative displacements of the housing 30 and said mounting flange 18.

6. A device according to claim 5, further characterized in that said batch hopper 26 and 28 is supported by its rigid support structure 22 and that said housing 30 is rigidly supported by said hopper. device according to claim 5, further characterized in that said housing

30 is supported by said rigid support structure 22, and in that a second expansion joint 72 is connected between said housing 30 and said batch hopper 26 and 28.

8. A device according to claim 1, further characterized in that said bearing ring 40 is directly supported in said housing 30 through the intermediation of said deformable connecting element 90.

9.- A compliance device with claim 8, further characterized in that said deformable connecting element 90 is a sleeve with deformable wall.

10. A device according to claim 1, further characterized in that said housing 30 is supported through the intermediation of said deformable joining element 100 in said mounting flange 18.

11. A device according to claim 10 , further characterized in that said deformable connecting element 100 comprises a lower mounting flange 102, an upper mounting flange 104, a wall

The deformable metallic "" "is dimensioned in such a way as to support the weight of the conduit assembly 32 / housing 30, and stops 108 and 110 which limit the relative displacements of the flanges.

12. A device according to claim 11, further characterized in that said deformable metal wall 106 consists of a loop filled with a compressible insulating material 112.