EP1880157B1 - Cooled roller for handling steel products - Google Patents

Abstract

The invention concerns a roller (R), used in continuous product heating furnaces for handling and conveying steel products and in particular slabs. The associated apparatus includes a cooled central shaft (1), cooled by a liquid. On the shaft are mounted a plurality of discs (2), for supporting the products (3) to be transported, arranged perpendicularly to the longitudinal geometrical axis of the roller (R), spaced apart along the axis of the roller (R) and separated by an insulating sleeve (4). The insulating sleeve (4) is maintained at each longitudinal end by at least one cold component (5) secured to the shaft (1) and cooled by the shaft, with axial play (Ja) between the sleeve (4) and the shaft (1) such that possible sagging of the shaft (1) may occur in use without causing substantial mechanical stress on the insulating sleeve (4) and the heat transferred from the sleeve (4) to the shaft (1), and from the discs (2) to the sleeve (4) is limited.

Description

The present invention relates to a roller, used in particular in its continuous furnaces for heating long products, for the handling and conveying of steel products and in particular slabs.

• la nature et les caractéristiques des produits se déplaçant dans le four, notamment poids, dimensions, forme, etc...
• les conditions d'ambiance thermique régnant dans le four, dépendantes de la température à laquelle le produit doit être chauffé,
• la nature de l'atmosphère à l'intérieur du four, oxydante ou réductrice,
• la plage de vitesses à laquelle le produit doit être déplacé dans le four.

It is known that the design and realization of this type of rollers must be made so that they are in line with:

• the nature and characteristics of products moving in the oven, including weight, dimensions, shape, etc.
• the thermal environment conditions prevailing in the oven, dependent on the temperature at which the product is to be heated,
• the nature of the atmosphere inside the oven, oxidizing or reducing,
• the range of speeds at which the product must be moved in the oven.

In addition, these handling and conveying rollers must be designed and manufactured so that they ensure good product guidance throughout the oven while limiting the thermal marking of the products.

In addition, the life of the rollers during which they maintain their initial level of performance must be sufficiently important compared to other mechanical equipment constituting the oven.

EP 0 345 147 discloses rollers consisting of a cooled central shaft having a plurality of discs perpendicular to the geometric axis of said shaft, each of said discs being provided with a tread in contact with the product moving in the furnace, the discs being separated by an insulating sleeve.

This technique as all of those implemented today is not entirely satisfactory, in particular because of a too limited life of the roller, related to the deterioration of the insulating sleeves caused by the mechanical stresses exerted by the bending movements of the central shaft during the passage of products. Thermal stresses also contribute to deterioration of the insulating sleeves.

The object of the invention is, above all, to propose a technical solution that makes it possible to substantially reduce the mechanical stresses, and preferably also the thermal stresses, on the insulating sleeves.

According to the invention a roller, used in particular in continuous furnaces for heating long products, for the handling and conveying of steel products and in particular slabs, comprising a cooled central shaft, in particular by a liquid, on which are mounted a plurality of disks, serving as a support for the products to be conveyed, arranged perpendicularly to the longitudinal geometric axis of the roller, spaced along the axis of the roll and separated by an insulating sleeve, is characterized in that the insulating sleeve is maintained at each longitudinal end by at least one cold part integral with the shaft and cooled by the shaft, with an axial clearance between the sleeve and the cold part, and a radial clearance between the sleeve and the shaft so that a possible deflection of the shaft can occur in operation without causing significant mechanical stress on the insulating sleeve and that heat transfer from the sleeve to the arb re, and discs to the sleeve are limited.

According to a first possibility, the sleeve is supported radially at each axial end by the cold part.

Alternatively, the sleeve is supported radially by the shaft.

The cold room may be distinct from the neighboring disk. The areas of contact between the insulating sleeve and the cold parts are limited to the axial end regions of the sleeve so that these reduced contact areas and the clearance between the insulating sleeve and the cold parts can limit the heat transfer of the sleeve. to cold rooms.

The cold room may be constituted by a stepped ring or by at least two stops locked in rotation and in translation on the central shaft. Locking of the ring or cleat can be done by welding on the shaft. The cold room can also constitute a stop piece in translation and in rotation of a disc, which can be mounted with a radial play on the shaft, free in rotation and in translation.

A spacing radial gap may be provided between the shaft and the inner cylindrical surface of the insulating sleeve; the outer cylindrical surface of the insulating sleeve may be free.

The inner cylindrical surface of the insulating sleeve may consist of a cylindrical metal skirt around which is molded an insulating material, in particular refractory concrete. The sleeve can, in alternatively, consist of a succession of cylindrical metal screens separated by air knives.

The rectilinear generatrices of the cylindrical skirt may extend axially above the cold parts, which radially support the skirt and the sleeve, the skirt having an internal diameter greater than the outer diameter of the shaft of a value determining the radial dimension. infill space; inside the skirt, towards each of its axial ends and on the side of the cold part opposite the adjacent disk, is provided a ring, projecting radially inwards, in a plane orthogonal to the geometric axis of the shaft, the axial clearance and the radial clearance are provided, on the one hand, between the cold part and the adjacent face of the crown and, on the other hand, between the shaft and the diameter of the opening of the crown surrounding the tree.

According to one variant, the radial clearance is provided between the inside diameter of the skirt and the outside diameter of the shaft and the axial ends of the skirt have a radially outward recess followed by an axial cylindrical return, the skirt is supported radially by the shaft, and the axial clearance is provided between the facing faces of the cold part and the recess.

The insulating sleeve can be rotatably mounted on the shaft.

Other characteristics and advantages of the invention will appear in the description which follows with reference to the accompanying drawings but which has no limiting character.

• Fig. 1 est une coupe longitudinale, suivant la ligne I-I de Fig.2, d'un rouleau selon un premier mode de réalisation de l'invention.
• Fig. 2 est une coupe du rouleau suivant la ligne II-II de Fig. 1.
• Fig. 3 est un détail de parties du rouleau de Fig. 1, à plus grande échelle.
• Fig. 4 est une vue en perspective éclatée d'éléments du rouleau de Fig. 1.
• Fig. 5 est une vue en perspective éclatée d'un autre mode de réalisation des éléments de Fig. 4.
• Fig. 6 est une coupe longitudinale, suivant la ligne VI-VI de Fig.7, d'un rouleau selon un deuxième mode de réalisation de l'invention.
• Fig. 7 est une coupe du rouleau suivant la ligne VII-VII de Fig. 6.
• Fig. 8 est une coupe longitudinale, suivant la ligne VIII-VIII de Fig.9, d'un rouleau selon un troisième mode de réalisation de l'invention.
• Fig. 9 est une coupe du rouleau suivant la ligne IX-IX de Fig. 8, et
• Fig. 10 est un détail de parties du rouleau de Fig. 8, à plus grande échelle.

On these drawings:

• Fig. 1 is a longitudinal section along line II of Fig.2 of a roll according to a first embodiment of the invention.
• Fig. 2 is a section of the roll along line II-II of Fig. 1 .
• Fig. 3 is a detail of parts of the roll of Fig. 1 , on a larger scale.
• Fig. 4 is an exploded perspective view of elements of the roll of Fig. 1 .
• Fig. 5 is an exploded perspective view of another embodiment of the elements of Fig. 4 .
• Fig. 6 is a longitudinal section along line VI-VI of Fig.7 , a roller according to a second embodiment of the invention.
• Fig. 7 is a section of the roll along line VII-VII of Fig. 6 .
• Fig. 8 is a longitudinal section along line VIII-VIII of Fig.9 , a roller according to a third embodiment of the invention.
• Fig. 9 is a section of the roll along line IX-IX of Fig. 8 , and
• Fig. 10 is a detail of parts of the roll of Fig. 8 , on a larger scale.

To refer at Fig. 1 to Fig. 3 it can be seen that a roller R according to the invention comprises a hollow central shaft 1 of substantially horizontal geometric axis, on which are mounted disks 2, which serve as support for steel products 3 to be conveyed, for example slabs relatively high temperature, especially of the order of 1000 ° C or more, through a not shown heating furnace. The hollow shaft 1 comprises, inside, a coaxial tube 1a defining, between its outer surface and the inner surface of the shaft 1, an annular space 1b. The shaft 1 is cooled by a circulation of water, for example which arrives in the annular space 1b and returns through the tube 1a.

The discs 2 are arranged perpendicular to the longitudinal axis of the roll R, spaced along this axis. Two successive discs 2 are separated by a cylindrical insulating sleeve 4. The periphery of each disc 2 constitutes a tread 2a in contact with the product 3. This tread 2a extends on either side of the median plane of the disc 2. The disc 2 comprises, at the level of the 1, a guide flange 2b whose axial extent is optimized to allow effective guiding of the disc 2 on the shaft 1. The inner diameter of the flange 2b is slightly greater than the outer diameter of the shaft 1, a value allowing free mounting in rotation and in translation of the disks 2 on the shaft 1. The disks 2 are not therefore directly integral with the shaft 1. An air interface exists between the collar 2b and the shaft 1 over most of the circumference, and brakes the heat transfer from disk 2 to shaft 1.

The insulating sleeve 4 constitutes a volume entirely of revolution about the axis of the roll, allowing the production of a simple and robust part, advantageously made of refractory concrete.

The insulating sleeve 4 is held at each longitudinal end by at least one cold part 5 with an axial clearance Ja ( Fig.3 ) between the sleeve 4 and the cold part 5 and a radial clearance Jr ( Fig.3 ) between the sleeve 4 and the shaft 1. The games Ja and Jr allow a possible deflection of the shaft 1, in operation, without causing significant mechanical stress on the sleeve 4. The values of the games Ja and Jr are determined according to the operating conditions and dimensions of the rolls. As an indication, not limiting, the games Ja and Jr are generally greater than two millimeters.

According to the embodiments of the Fig. 1 to 3 , and Fig. 6.7 the sleeve 4 is supported radially by the cold part 5. A radial clearance Er exists between the sleeve 4 and the part 5. The clearance Er is preferably less than half the radial clearance Jr between the sleeve 4 and the shaft 1 .

As it appears in the drawings, the sleeve 4 may be formed of an assembly of several integral parts. The games are to be considered between the cold part 5, the shaft 1, and the nearest surface of the part integral with the sleeve 4.

The cold room 5 may be distinct from the neighboring disc 2 so that a continuity solution is formed between them and creates a thermal barrier. The part 5, cooled by conduction by the shaft 1 and separated from the disk 2, is in operation at a temperature which is substantially lower than that of the neighboring disc 2.

The longitudinal ends of the sleeve 4 are spaced axially from the disc 2 adjacent to a distance k, at least greater than twice that of Ja, so that the insulating sleeve 4 is not in contact with the hot discs 2. The thermal stresses and The mechanical joints on the sleeve 4 are reduced.

In the same perspective of limiting the heat exchange, the implementation of reduced contact areas at the axial ends of the sleeve, in particular by introducing radial and axial clearances, between the insulating sleeve 4 and the cold parts 5 makes it possible to limit the transfer of heat insulation sleeve 4 to cold rooms 5.

Each cold part 5 can be constituted by a shoulder ring 6 ( Fig. 4 ) or by at least two cleats 7 ( Fig. 5 ) blocked in rotation and in translation on the central shaft 1. The locking can be performed by welding on the shaft 1 of the ring 6 or the cleat 7, made of a steel allowing this welding. The welding also ensures the cooling of the parts 5 by conduction.

Advantageously, the cold parts 5 further serve to stop in translation and in rotation the disk 2 on the shaft 1. For this, the cold parts 5 comprise shoulders 5a in axial projection adapted to engage in corresponding notches 2c provided in the flanges 2b of the discs 2. Two notches 2c diametrically opposite are shown on Fig.4 and 5 . It is possible to provide more, especially three spaced angularly 120 °.

The discs 2 being mounted with a radial clearance on the shaft, this clearance allows free expansion of the discs 2 relative to the central shaft 1, thus removing the thermomechanical stresses between these parts.

An interspace 8 may be provided between the shaft 1 and the insulating sleeve 4.

The insulating sleeve 4 may comprise an inner metal cylindrical skirt 9 surrounded, and secured to, a molded refractory concrete casing 4a ( Fig. 1 to 3 ) whose outer surface is free, or formed of a succession of metal screens 4b ( Fig.6 and 7 ) separated by air knives. The metal screens 4b oppose the radiative heat transfer between the atmosphere of the furnace and the cooled shaft 1 of the roller R.

According to the achievements of Fig.1 to 3 , and Fig.6 and 7 , the rectilinear generatrices of the cylindrical skirt 9 extend axially (see FIG. Fig.3 ) above the cold parts 5, which radially support the skirt 9 and the sleeve 4. The skirt 9 has an inner diameter greater than the outer diameter of the shaft 1 by a value h determining the radial dimension of the space 8 Inside the skirt 9, towards each of its axial ends and on the side of the stop means 5 opposite the adjacent disc 2, there is provided a ring 10, projecting radially inwards, in a plane orthogonal to the geometric axis. The games Ja and Jr, mentioned above, are provided on the one hand between the cold part 5 and the adjacent face of the ring 10 and, on the other hand, between the shaft 1 and the diameter of the opening of the ring 10 surrounding the tree 1.

Fig. 8 to 10 illustrate another embodiment of a roller R according to the invention where the spacer space 8 of Fig.3 is deleted. The insulating sleeve 4 further comprises a cylindrical metal skirt inner 9c surrounded and secured to an insulating casing 4c, for example refractory concrete. The radial clearance Jr is provided between the inner diameter of the skirt 9c and the outer diameter of the shaft 1, which radially supports the skirt 9c and the sleeve 4. The axial ends of the skirt 9c have a radial recess 10c towards the outside followed by an axial cylindrical return 10d which overcomes the cold part 5. The axial play Ja is provided between the facing faces of the cold part 5 and the recess 10c. Between the piece 5 and the sleeve 4 / skirt 9c there is a clearance Nr equal to at least twice the clearance Jr between the shaft 1 and the sleeve.

The insulating sleeve 4 can be rotatably mounted on the shaft 1, without being driven by the ring 6 or the cleats 7.

The operation of the roller R results from the foregoing explanations. At the passage of a slab 3, the shaft 1 can undergo a deflection which will cause a decrease in the clearances Ja and / or Jr without however removing them, so that the sleeves 4 are protected from mechanical and thermal stresses.

Claims (15)

1. Roller (R), used especially in continuous furnaces for reheating long products, for the handling and conveying of iron and steel products, particularly slabs, comprising a central cooled arbor (1) on which a plurality of discs (2) is mounted, serving as support for the products (3) to be conveyed, said discs being placed perpendicular to the longitudinal geometric axis of the roller (R), away from the axis of the roller and separated by an insulating sleeve (4), characterized in that the insulating sleeve (4) is held in place at each longitudinal end by at least one cold part (5) fastened to the arbor (1) and cooled by the arbor, with an axial clearance (Ja) between the insulating sleeve (4) and the cold part (5) and with a radial clearance (Jr) between the sleeve (4) and the arbor (1) so that any bending of the arbor (1) may occur in operation without generating a substantial mechanical stress on the insulating sleeve (4) and so that the heat transfer from the insulating sleeve (4) into the arbor (1) and from the discs (2) into the sleeve (4) is limited.
2. Roller according to Claim 1, characterized in that the insulating sleeve (4) is supported radially at each axial end by a cold part (5).
3. Roller according to Claim 1, characterized in that the insulating sleeve (4) is supported radially by the arbor (1).
4. Roller according to one of the preceding claims, characterized in that the cold part (5) is away from the adjacent disc (2).
5. Roller according to one of the preceding claims, characterized in that the cold part (5) is formed by a shouldered ring (6) prevented from moving rotationally and translationally on the central arbor (1).
6. Roller according to one of Claims 1 to 4, characterized in that the cold part (5) is formed by at least two stops (7) prevented from moving rotationally and translationally on the central arbor (1).
7. Roller according to any one of the preceding claims, characterized in that the cold part (5), welded to the cooled arbor (1), further constitutes a stop part, stopping a disc (2) from moving translationally and rotationally.
8. Roller according to Claim 7, characterized in that the disc (2) is mounted with a radial clearance onto the arbor (1), which is free to move rotationally and translationally.
9. Roller according to any one of the preceding claims, characterized in that it includes an intervening space (8) between the arbor (1) and the insulating sleeve (4).
10. Roller according to any one of Claims 1 to 8, characterized in that the insulating sleeve (4) includes an internal cylindrical metal skirt (9, 9c).
11. Roller according to Claim 10, characterized in that the insulating sleeve (4) comprises a refractory concrete shell moulded around the cylindrical skirt (9, 9c).
12. Roller according to Claim 10, characterized in that the insulating sleeve (4) comprises a succession of cylindrical metal screens (4b) separated by air layers.
13. Roller according to Claim 10, characterized in that the linear generatrices of the cylindrical skirt (9) extend axially above the cold parts (5), the skirt (9) and the sleeve (4) being supported radially by said cold parts; the skirt (9) has an inside diameter larger than the outside diameter of the arbor by an amount (h) that defines the radial dimension of an intervening space (8); and, provided on the inside of the skirt, towards each of its axial ends and on the opposite side of the cold part (5) from the adjacent disc (2), is a ring (10) projecting radially inwards, in a plane orthogonal to the geometrical axis of the arbor, the clearances (Ja, Jr) being provided, on the one hand, between the cold part (5) and the adjacent face of the ring (10) and, on the other hand, between the arbor (1) and the diameter of the opening of the ring (10) surrounding the arbor (1).
14. Roller according to Claim 10, characterized in that the sleeve (4) is supported radially by the arbor (1), the radial clearance (Jr) is provided between the inside diameter of the skirt (9c) and the outside diameter of the arbor (1), and the axial ends of the skirt have a radially outward shoulder (10c) followed by an axial cylindrical return (10d), the axial clearance (Ja) being provided between the opposed faces of the cold part (5) and of the shoulder (10c).
15. Roller according to Claim 2, characterized in that the regions of contact between the insulating sleeve (4) and the cold parts (5) are limited to the axial end regions of the sleeve so that these small contact regions and the clearance between the insulating sleeve and the cold parts allow limited heat transfer from the sleeve to the cold parts.

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