EP0764220B1 - Loading device having a rotating chute for a melting furnace - Google Patents

Abstract

PCT No. PCT/EP95/01704 Sec. 371 Date Feb. 26, 1997 Sec. 102(e) Date Feb. 26, 1997 PCT Filed May 5, 1995 PCT Pub. No. WO95/33858 PCT Pub. Date Dec. 14, 1995A shaft furnace charging device with rotating chute comprises a supporting structure (22) overhanging the shaft furnace (10), a mounting flange (18) fixed rigidly to the shaft furnace (10), a batch hopper (26, 28) supported by the supporting structure (22), a drive housing (30) for the chute (32) which is connected in a sealed manner at one end to the batch hopper (26, 28) and at the other end to the mounting flange (18), and at least one large diameter roller ring (40) mounted in the housing (30) in order to support the chute (32) with the ring (40). In order to increase the working life of the roller ring (40), at least one deformable linking element (70) is incorporated in the chain of rigid elements connecting the mounting flange (18) to the roller ring (40), in such a way that a rigid transmission of deformations of the mounting flange (18) to the roller ring (40) is largely prevented.

Description

The present invention relates to a chute loading device rotary kiln, comprising a support structure overhanging the shaft furnace, a lock hopper supported by this support structure, a chute drive housing which is tightly connected to a side to the lock hopper and on the other side to a mounting flange to be fixed rigidly in the shaft oven, and at least one large rolling ring diameter mounted in the housing to support said rotary chute.

Such devices are described for example in documents US-A-3,693,812; US-A-3,880,302; US-A-3,814,403; US-A-4,941,792 and US-A-5,022,806. In these devices, the chute is suspended in a rotating cage, which is supported in the housing by means of a ring large diameter bearing. The rotating cage defines the lower part of a axial flow channel connecting the lock hopper to the chute, and the ring large diameter bearing externally surrounds this axial channel of flow. The bearing ring is designed to take up an axial force and a significant changeover moment. It includes two coaxial rings connected by rolling elements. One of the two rings is rigidly fixed to the rotating cage, while the other ring is rigidly fixed to a plate of support integrated in the housing. The housing itself has a flange lower using which it is rigidly supported on the mounting flange fixed to the shaft oven. The lock hopper is tightly connected to the casing, either rigidly. either through a compensator. In summary, in known devices the weight of the chute is transmitted rigidly through the support plate and the housing on the mounting flange from the shaft oven.

Many loading devices with a suspension of the chutes of this kind have been used in blast furnaces for more than 20 years. The large diameter bearing ring is the most reliable solution currently known to ensure the rotary suspension of the chute in the casing.

Although this type of suspension of the rotating chute gives full satisfaction, it should be noted, however, that the life of the ring large diameter bearing achieved in practice is significantly less than the lifespan you would expect from the calculations. This phenomenon is known for about ten years, but those skilled in the art could not not explain why in practice the bearing ring must be replaced earlier than predicted by calculations.

The problem underlying the present invention is to increase the duration life of the rolling ring in a device of the kind described in the preamble.

This problem is solved in at least one connecting element deformable which is integrated in the chain of rigid elements connecting mechanically the mounting flange rigidly attached to the shaft furnace at the ring bearing supporting the rotary chute, so that a transmission of deformations of said mounting flange to said bearing ring either largely avoided.

A certain merit of the present invention is to have understood that the flange assembly rigidly fixed to the shaft furnace undergoes deformations asymmetrical that affect the life of the bearing ring. These deformations of the mounting flange of the shaft furnace are due on one side to the internal pressure in the shaft oven and on the other side at thermal expansion of the shaft furnace. Their asymmetry is probably due to the fact the dome of the shaft furnace, to which the mounting flange is attached rigidly, is a non-symmetrical structure which presents for example several important local openings. Therefore, this dome deforms asymmetrically under the combined effect of internal pressure and constraints of thermal origin. In addition, this dome is not necessarily heated uniformly. In fact, the internal refractory lining may be less important in some places, which naturally produces heating asymmetric of the dome and therefore, in the wall of the dome, a field asymmetric constraints of thermal origin. In summary, the dome undergoes asymmetric deformations which necessarily generate deformations asymmetrical mounting flange attached to the dome.

In the devices according to the state of the art, these deformations asymmetric of the mounting flange are transmitted through a chain more or less rigid elements from the housing to the bearing ring. This last is therefore subject to a stress field and a asymmetric deformations which affect in particular its circularity and its flatness. This results in faster wear and therefore a reduction in its lifetime, or in some cases even a complete blockage of the ring bearing well before reaching its theoretically possible lifespan.

In the device according to the invention, the deformable connecting element, integrated in the chain of rigid elements connecting the mounting flange of the oven to tank with the rolling ring supporting the rotating chute, absorbs a much of the asymmetric deformation of the front mounting flange that these deformations cannot affect the geometry of the ring rolling.

In an advantageous first embodiment, the connecting element deformable is connected between a mounting plate and a liner outside of the housing. The bearing ring is fixed on this plate mounting and the outer casing of the casing is fixed directly to the flange of mounting fixed to the oven. The deformations of this flange are taken up in mainly by the deformable connecting element. The absorption effect obtained is improved if its support plate is provided with reinforcements giving it a much higher rigidity than that of the deformable element.

In a second advantageous embodiment of the invention, the element of deformable link is constituted by a first compensator which connects the casing containing said bearing ring, in a sealed manner to the flange of mounting the oven, while allowing relative movements between the casing and the oven furnace mounting flange. The housing is then supported either directly by a rigid support structure, or by the lock hopper. The latter is supported directly or indirectly by a structure of rigid support. Any rigid connection between the mounting flange and the housing supporting the bearing ring is therefore deleted.

In a third advantageous embodiment, the connecting element deformable is connected directly between an integrated mounting plate in the housing and the bearing ring. This solution naturally ensures better protection of the bearing ring, because of deformations of the support plate are also absorbed.

In the first and third execution, the connecting element deformable is preferably a ring whose annular wall defines a deformable loop.

In a fourth advantageous embodiment, the connecting element deformable according to the invention directly supports the casing on the flange mounting. This solution differs from the first execution described above by the fact that the deformable connecting element is capable of transmitting the weight of the housing / chute assembly directly on the mounting flange of the shaft furnace, whereas the compensator in the first execution is used exclusively for connect the housing tightly to the mounting flange of the shaft furnace and does not intervene in the recovery of the weight of the housing / chute assembly.

• la Figure 1 est une élévation, dessinée partiellement sous forme d'une coupe, d'un four à cuve équipé d'un premier mode d'exécution du dispositif de chargement à goulotte rotative selon l'invention;
• la Figure 2 représente, dans une vue analogue, une variante d'exécution du dispositif selon la Figure 1;
• la Figure 3 représente une coupe par un plan vertical d'un carter d'entraínement d'une goulotte rotative faisant partie d'un deuxième mode d'exécution du dispositif de chargement à goulotte rotative selon l'invention;
• la Figure 4 représente une coupe par un plan vertical d'un carter d'entraínement d'une goulotte rotative faisant partie d'un troisième mode d'exécution du dispositif de chargement à goulotte rotative selon l'invention;
• la Figure 5 représente une coupe par un plan vertical d'un carter d'entraínement d'une goulotte rotative faisant partie d'un quatrième mode d'exécution du dispositif de chargement à goulotte rotative selon l'invention;
• la Figure 6 représente un détail d'un élément de liaison déformable de la Figure 6.

Other advantages and characteristics of the invention will be deduced from the detailed description of several preferred embodiments of the invention and from the representations of these preferred embodiments in the attached drawings, in which:

• Figure 1 is an elevation, partially drawn in the form of a section, of a shaft furnace equipped with a first embodiment of the loading device with rotary chute according to the invention;
• Figure 2 shows, in a similar view, an alternative embodiment of the device according to Figure 1;
• Figure 3 shows a section through a vertical plane of a drive housing of a rotary chute forming part of a second embodiment of the loading device with rotary chute according to the invention;
• Figure 4 shows a section through a vertical plane of a drive housing of a rotary chute forming part of a third embodiment of the loading device with rotary chute according to the invention;
• Figure 5 shows a section through a vertical plane of a drive housing of a rotary chute forming part of a fourth embodiment of the loading device with rotary chute according to the invention;
• Figure 6 shows a detail of a deformable connecting element of Figure 6.

Referring first to Figure 1, it will be noted that the reference 10 marks overall a tank oven. This is for example a blast furnace, but it could also be another type of oven which can be fitted with a chute rotary. The tank furnace shown comprises a cylindrical body 12 and a terminal dome 14. In this terminal dome 14 is integrated an opening of load 16 which is surrounded by a mounting flange 18, called in the continued mounting flange 18 of the shaft furnace 10. This mounting flange 18 is rigidly attached to dome 14 and is therefore exposed to all deformation of the last.

une trémie fixe ou rotative 24, recevant la matière de chargement;

une trémie d'éclusage 26, qui peut être rendue étanche d'un côté par rapport à la trémie 24 et de l'autre côté par rapport au four 10;

un organe de dosage 28 de la matière de chargement, qui est, le plus souvent, un élément indépendant agencé en dessous la trémie d'éclusage 26, mais qui, pour simplifier la terminologie, est considéré dans la présente description comme faisant partie de la trémie d'éclusage 26;

un carter d'entraínement 30; et

une goulotte 32 qui peut tourner autour de l'axe vertical du four à cuve 10 et dont l'angle d'inclinaison par rapport à la verticale peut, le plus souvent, être varié.

Reference 20 generally identifies a loading device with a rotary chute. The latter first comprises a support structure 22 which overhangs the dome 14 of the shaft furnace and which rests for example on the body 12 of the shaft furnace. In some cases the shaft furnace is however surrounded by an independent supporting structure, called a square tower, and the support structure 22 will be supported by this square tower. From top to bottom we can see in Figure 1:

a fixed or rotary hopper 24, receiving the loading material;

a lock hopper 26, which can be sealed on one side with respect to the hopper 24 and on the other side with respect to the furnace 10;

a metering member 28 of the loading material, which is most often an independent element arranged below the lock hopper 26, but which, to simplify the terminology, is considered in the present description to be part of the lock hopper 26;

a drive housing 30; and

a chute 32 which can rotate around the vertical axis of the shaft furnace 10 and whose angle of inclination relative to the vertical can, most often, be varied.

The load material flows from the lock hopper 26 through the metering member 28 and the casing 30 on the rotary chute 32. The latter distributes the loading material on the loading surface marked by the reference 34. The casing 30 contains the means for suspending the chute as well as the training means thereof. Different types of means suspension and drive of chute 32 are described in detail in documents cited in the introductory part of this description. Help of Figure 3 we will only provide here a brief description of a mode possible execution of these suspension and drive means of the chute.

Referring thus to Figure 3, we see that the chute 32 is supported by a rotary cage 36 by means of two lateral pivots 38 'and 38 ". These lateral pivots 38 'and 38 "define a horizontal pivot axis for the chute 32 around which the inclination of the chute can be varied by compared to the vertical. The rotating cage 36 forms the lower part of a channel supply 39 which is coaxial with the axis of the oven 10. This cage 36 is supported in the casing 30 by means of a bearing ring 40 of large diameter which surrounds the supply channel 39 and which defines the axis of rotation vertical of the cage 36. This rolling ring 40 is an element which has proven for the rotary suspension of chute 32. It includes a inner ring 42 and an outer ring 44 which are connected by rolling elements 46 so as to be able to withstand axial loads and significant switching moments. It is preferably the outer ring 44 which supports the rotary cage 36, while the inner ring 42 is fixed on a support plate 48 of the casing 30. The outer ring 44 supports then a gear toothing 50 which cooperates with a first pinion (not shown) a drive mechanism (not shown) to train in rotation of the cage 36 and, consequently, the chute 32 around the axis of the tank 10.

A swivel mechanism allows you to change the angle of inclination of the chute 32 when the latter is rotating. This mechanism includes the most often a second large diameter bearing ring 52, the inner ring 54 is fixed to the support plate 48. The outer ring 56 of this second rolling ring is provided with a gear teeth 58 which cooperates with a second pinion (not shown) of a mechanism training. This drive mechanism is capable of giving the ring exterior 56 a rotational movement which may have a phase shift variable angular with respect to the rotational movement of the cage 36. A mechanism 60, mechanically connected between this outer ring 56 and a at least pivots 38 ', 38 "makes it possible to transform this phase shift or offset angular in a pivoting of the chute around the two pivots 38 'and 38 ". such pivoting mechanisms are described in more detail in the documents mentioned in the introduction to this description.

According to the present invention at least one deformable connecting element is integrated into the chain of rigid elements mechanically connecting the ring bearing 40 supporting the rotary chute 32 to the mounting flange 18 of the shaft furnace, so that a rigid transmission of deformations between the mounting flange 18 and the rolling ring 40 is avoided. Figures 1 to 5 show several advantageous embodiments of the invention.

According to the execution of Figure 1 a compensator 70 is connected between the flange 18 of the dome 14 and the counter-flange 18 'of the casing 30. This compensator 70, for example a metallic bellows compensator, guarantees watertightness between the casing 30 and the shaft furnace 10, while allowing relative movement of the two flanges 18 and 18 '. The casing 30 is supported by the hopper assembly lock 26 / metering member 28. This assembly 26/28 is supported itself, as described above, by the support structure 22. The compensator 70 must therefore essentially fulfill a function seal and must in no way support the weight of the housing assembly 30 / chute 32. It will therefore be appreciated that in this embodiment the dome 14 can deform asymmetrically, for example under the influence of a field of asymmetric temperature or internal pressures acting on the dome, without that these deformations affect the casing 30. The integrated bearing ring 40 in the casing 30 is therefore protected from tensions induced by the asymmetric deformations of the dome 14.

The device according to Figure 2 differs from the device of Figure 1 by the fact that the casing 30 is supported directly by the support structure 22. A second compensator 72 is connected between the hopper assembly lock 26 / shutter member 28 and the casing 30. This embodiment has the advantage that the casing 30, which is generally hotter than the hopper lock 26, 28, can expand almost freely on both sides. In addition, this second compensator is recommended if continuous weighing is to be carried out of the lock hopper via integrated load cells in the supports of the hopper 26 on the support structure 22.

Figure 3 shows a preferred embodiment of the invention, in which the deformable connecting element is integrated in the casing 30. This deformable connecting element more precisely comprises a ring deformable 80 connected between the support plate 48 of the casing and a outer jacket 82 of the casing 30. This modified casing 30 can be rigidly mounted on the mounting flange 18 of the shaft furnace 10. Indeed, the deformations of this flange 18 affect the wall 82 of the casing 30, but not or little the plate support 48. It will be noted that the latter is advantageously reinforced by boxes 84 which increase its rigidity. Indeed, the higher the plate support 48 is rigid with respect to the deformable ring 80, the better deformation of the outer jacket 82 will be taken up by the ring deformable. A high rigidity of the support plate 48 amplifies by therefore the effect of absorbing deformations of the deformable ring 80 and thus guarantees that the support plate 48 does not deform either in its plane or perpendicular to this plane. In conclusion, a deformation of the dome 14 induced in the ring 42 of the rolling ring 40, which is fixed to the support plate 48, hardly any deformations affecting the circularity and the flatness of this ring 42.

The deformable ring 80 is for example a ring having a section open in "U". One of the branches then constitutes a fixed flange, for example welded to the wall 82; while the other branch constitutes a fixed flange, by example welded to the support plate 48. The ring 80 is, as we have seen more high, dimensioned to be much less rigid than the plate support 48. It follows that the deformations of the wall 82 produce a deformation of section "U" of ring 80 and do not affect the shape of the plate 48.

Figure 4 also shows an embodiment in which the element of deformable link is integrated in the casing 30. In this embodiment the outer casing 30 and support plate 48 are assembled more or less rigidly. Between the support plate 48 and the ring bearing 40 is connected against a deformable sleeve 90. The latter absorbs any deformation of the support plate 48 without transmit significant stresses to the bearing ring 40. The casing modified from Figure 4 can also be rigidly mounted on the flange 18 of the dome 14.

Figure 5 shows an execution of a deformable connecting element 100 which can be integrated between the casing 30 and the dome 14 and which has the particularity of being able to transmit the weight of the casing 30 / chute assembly 32 on the dome 14. The deformable element 100 comprises a lower flange 102, fixed to the dome 14, and a mounting flange 104, supporting the casing 30. The two flanges are 102 and 104 are connected by a metal wall 106 deformable which forms an open loop inwards. It will be noted that this loop preferably has the shape of a lyre. This metal wall 106 is dimensioned so as to be able to transmit the weight of the housing assembly 30 / chute 32 of the mounting flange 104 on the lower flange 102, while allowing a relative horizontal and / or vertical displacement of the two flanges 102 and 104. However, in order to avoid excessive relative movements of the two flanges 102 and 104, which could cause plastic deformation of the metal wall 106, stops 108 and 110 have been provided. avoid excessive compression of the deformable element 100. The elements 110, on the other hand, avoid too great an extension, as well as a excessive horizontal displacement of the two flanges 102 and 104. It is note that the purpose of the tie rods 110 is in particular to avoid an extension excessive axial of the loop formed by the wall 106 under the effect of the internal pressure in the oven (bottom effect).

Figure 6 shows a detail of a preferential execution of the element deformable 100. It can be seen that the loop formed by the wall 106 is entirely filled with a material 112. It is an insulating and compressible material, for example rock wool. An annular screen 114 closes the opening of the loop, without interfering with the deformation thereof. This element execution deformable 100 has the advantage that the deformable wall 106 is protected against excessive heating, which would negatively influence its properties elastic. In addition, it is excluded that the cavity inside the loop fills with non-compressible materials, which could hinder deformation of the wall 106.

It will be appreciated by those skilled in the art that two or more of the executions offered can be combined in a loading device with rotary chute for a shaft oven, in order to support each other in their effects of absorption of the deformations of the dome 14. Thus one can by example combine the solution of Figure 3 with the solution of Figure 2 or 5, the solution of Figure 4 with all the other solutions.

Claims (12)

1. Shaft furnace charging device with rotating chute, comprising

   a supporting structure (22) rising above the shaft furnace (10),

   a mounting flange (18) to be fixed rigidly to the shaft furnace,

   a batch hopper (26, 28) supported by the supporting structure (22),

   a drive housing (30) for the chute (32) which is connected in a sealed manner at one end to the batch hopper (26, 28) and at the other end to said mounting flange (18),

   at least one large diameter bearing ring (40) mounted in the housing (30) and supporting said rotating chute (32),

   said ring (40) being connected mechanically to said mounting flange (18) by a chain of rigid elements,

      characterised by

   at least one deformable linking element (70, 80, 90, 100) incorporated in said chain of rigid elements between said mounting flange (18) and said bearing ring (40) supporting the rotating chute (32), in such a way that a rigid transmission of deformations of said mounting flange (18) to said bearing ring (40) is largely avoided.
2. Device according to Claim 1, characterised

   in that said housing (30) comprises an outer jacket (82) connected in a sealed manner between said mounting flange (18) and said batch hopper (26, 28) and a mounting plate (48) with high rigidity on which is mounted said bearing ring (40), and

   in that said deformable linking element (80) supports said mounting plate (48) in said jacket (82).
3. Device according to Claim 3, characterised in that said deformable linking element (80) has a U- shaped section.
4. Device according to Claim 2 or 3, characterised in that said mounting plate (48) includes reinforcements (84) increasing its rigidity.
5. Device according to Claim 1, characterised in that said deformable linking element comprises a first expansion joint (70) which connects said housing (30) in a sealed manner to said mounting flange (18) while allowing relative displacements of the housing (30) and said mounting flange (18).
6. Device according to Claim 5, characterised in that said batch hopper (26, 28) is supported by said rigid supporting structure (22) and in that said housing (30) is rigidly supported by said hopper.
7. Device according to Claim 5, characterised

   in that said housing (30) is supported by said rigid supporting structure (22), and

   in that a second expansion joint (72) is connected between said housing (30) and said batch hopper (26, 28).
8. Device according to Claim 1, characterised in that said bearing ring (40) is directly supported in said housing (30) by means of said deformable linking element (90).
9. Device according to Claim 8, characterised in that said deformable element (90) is a sleeve with deformable wall.
10. Device according to Claim 1, characterised in that said housing (30) is supported by means of said deformable linking element (100) on said mounting flange (18).
11. Device according to Claim 10, characterised in that said deformable linking element (100) comprises

    a lower mounting flange (102),

    an upper mounting flange (104),

    a deformable metallic wall (106) connecting in a sealed manner the lower flange (102) to the upper flange (104), said deformable metallic wall being dimensioned so as to support the weight of the chute (32)/housing (30) assembly, and

    stops (108, 110) limiting the relative displacements of the two flanges.
12. Device according to Claim 12, characterised in that said deformable metallic wall (106) comprises a loop filled with an insulating compressible material (112).

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