FR2691791A1 - Refractory lining of beams for ovens, especially metallurgical and ceramic. - Google Patents

Abstract

Refractory lining for skids for metallurgical or ceramic furnaces, characterised in that it is constituted by an assembly of composite elements, either premoulded in a workshop or cast on site, of a shape which is generally parallelepipedal, and it also comprises firstly a ring (2) made on a basis of aluminous refractory concrete with coarse aggregates, the hollow space (3) in its centre is filled on mounting with an insulating material, the whole rests on its lower face (6) on a metal structure connected to the device for displacement of said skids, while the upper face (5) of said assembly is surmounted by a block of aluminous concrete (1), and the sandwich thus formed is passed through over its entire thickness by a plurality of means for fixing (7) and blocking (10, 11).

Description

1 - The present invention relates to an embodiment of parts

  being part of steel installations and in particular for metallurgical or ceramic furnaces. These parts more precisely constitute the lining of mobile beams to be used for the movement of steel products In a traditional metallurgical furnace, the raw products in the form of slabs or billets must undergo gradual heating, before their transformation and their passage in rolling mill trains hot, in processed products10 such as sheets, wires, drawn In the case of a ceramic furnace, these linings provide sufficient residence time and therefore optimum firing of the various pieces of ceramic. Currently, the transfer in the various zones of an oven is ensured by the displacement of mobile beams that are

  nomons spars The kinetics of displacement is assimilated to a back and forth movement known by the term "no pilgrim".

  These beams must not only support the large masses and the inertia resulting from the movement, but above all have an excellent resistance to thermal abrasion taking into account the high temperature levels reached, between 1200 e C and 1350 a C, times of important stays in an often oxidizing atmosphere. All these thermo-mechanical constraints impose on the users of these ovens a periodic repair of the lining constituting the beams. The known linings generally consist of a single block of refractory concrete poured or added in situ within the structure of the beam. These concretes do not have any particular characteristics depending on the areas of the spar in contact with the

  product to be transported, indeed some will be more sensitive to thermal abrasion and others to mechanical erosion.

  During the repair, on the one hand, the concrete blocks, of considerable mass, are often of difficult access, not facilitating the task of the users and on the other hand being in one piece, they are caused to change more than 2 -

  necessary making the operation expensive.

  The present invention proposes to improve and simplify the process of reconditioning the side member linings, by the use of lining blocks previously produced in the workshop and cast in situ, easy to handle. These linings have the particularity of be made up of an assembly of refractory and composite concretes with their own characteristics. The invention therefore relates to a refractory lining of beams for metallurgical and ceramic furnaces, characterized in that it consists of an assembly of composite elements either pre-molded in the workshop, or cast on site, of generally parallelepipedal shape and it further includes, first of all a ring based on aluminous refractory concrete with large aggregates, the space hollowed out in its center is filled when mounting an insulating material, the assembly rests on its underside on a structure

  metallic linked to the movement device of said beams, while the upper face of said assembly is capped by a block of aluminous concrete, the sandwich thus formed is traversed over its entire thickness by a plurality of fixing and blocking means.

  Other characteristics and advantages of these linings will become apparent from the following description of a mode

  of elaboration, given by way of nonlimiting indication On the figures: FIG. 1 is a sectional view of a lining element for spar; Figure 2 is a plan elevational view of the same

packing element.

  According to a preferred embodiment of these linings for side rails, there is on the metal structure linked to the movement mechanism of these side rails and on a concrete base 4 secured to this same metal structure located in the furnace, a ring 2 made of concrete aluminous refractory, of generally parallelepiped shape, which is manufactured and dried in the workshop, which gives them optimum mechanical strength 3 - contr 8 lée The space 3 hollowed out in its center is either filled when mounting an insulating concrete 14, or filled by a stack of insulating bricks also capable of withstanding a temperature close to 12000 C, this whole assembly rests on its lower face 6 on said structure, while the upper face 5 is

  surmounted by a block of aluminous concrete 1 cast in situ.

  The lateral faces of the central core 14 in contact with those of the ring 2 are covered with an expansion joint

  thermal and mechanical, in particular produced using paraffin.

  The upper 5 and lower 6 faces, facing the concrete layer 1 and the structure 4 respectively, are covered with cardboard plates 5 ′ and ceramic fibers 6 ′ constituting

mechanical expansion joints.

  The upper face of the ring 2 comprises over its entire periphery a plurality of blind cavities 11, the lateral faces 17 of which are with negative undercuts, such as in particular of the dovetail type, these cavities are subsequently filled with the concrete of the layer upper 1, thus creating non-removable anchor points, this construction system cancels the "tearing-out" phenomenon observed in operation and caused by the sticking of slabs and billets on said spars The stack formed by the ring 2, the upper layer of concrete 1, the frame 4 and its metallic structure, is traversed over its entire thickness by a plurality of means 7 ensuring the

  fixing and blocking of the assembly.

  These fixing means 7 are provided with very long anchors, possibly in several pieces, joined at their common end by a ring 8 which can be threaded. These anchors are shaped like a "Christmas tree", the parts protruding 9 from the main rod serve as sealing tabs for the layers of concrete poured in the workshop or in situ One of the ends of these fixing means opens out through the metal structure of the spar and is fitted with

  9 ′ compensation, notably chosen from elastic washers.

  In addition, fixing lugs 10 are provided on the ceramic fiber plate 6 ′, similar to the sealing lugs 9, 4 - directed outwards and having to be embedded in the material.

  insulation filling the hollow space 3.

  The upper face 16 of the concrete layer 1 covering the ring 2 and the insulating concrete 14 or the stack of bricks, of the space 3 comprises a central recess 13, extending over the entire length of the lining, intended for reduce and limit the destructive effect of the points of support of the product on the refractory on the one hand, and reduce the gray areas on the slabs or billets

on the other hand.

  Furthermore, taking into account the high temperature levels reached and the possible risks of erosion, machining operations 12 in the form of a bevel are carried out on the outer lateral faces of the ring 2 which should allow the slag deflection outside of

  the area of the mechanisms ensuring the movement of the side members.

  The ring 2 consists of an aluminous refractory concrete with large aggregates titrating between 35 and 70% of alumina, intended to absorb the thermo-mechanical stresses, while the hollow space 3 is filled with either a concrete 14, either a stack of bricks, having insulating properties, intended to limit the

heat flow.

  This set of packings construction allows the local replacement of one or more damaged elements thanks to the disassembly of the fastening systems 7, to limit the erosion and cracking zones thanks to the construction in layers 1, 2, 4, protection effective mechanical areas in motion. It remains to be understood that the present invention is not limited to the exemplary embodiments described and produced above, but that it encompasses all variants thereof; this principle of construction of packing elements, very economical in maintenance and in manufacturing cost, can also be applied to various metallurgical furnaces, whether they have movable hearths,

  rotating, stationary, and petrochemical furnaces.

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Claims (5)

  1 refractory lining of beams for metallurgical and ceramic furnaces, characterized in that it consists of an assembly of composite elements either pre-molded in the workshop, or cast on site, of generally parallelepiped shape and 5 it further comprises, all 'first a ring (2) based on aluminous refractory concrete with large aggregates, the hollow space (3) in its center is filled with the assembly of an insulating material, the assembly rests on its underside (6) on a metallic structure linked to the device for moving said longitudinal members, while the upper face (5) of said assembly is capped by a block of aluminous concrete (1), the sandwich thus formed is traversed over its entire thickness by a plurality of fixing means ( 7) and blocking (10, 11).  2 refractory lining of longitudinal members for metallurgical and ceramic furnace according to claim 1, characterized in that there is provided a thermal and mechanical expansion joint located over the entire lateral periphery of the central core (3) and at the interface of the surfaces in contact based in particular on paraffin. 3 Refractory lining of oven side members   metallurgical and ceramic according to claims 1 or 2, characterized in that the central core (3) is provided on its faces   lower (6) and upper (5) and between the two layers (1, 4) of concrete added in situ, of plates (5 ', 6') based in particular on cardboard and ceramic fibers. 25 4 Refractory lining of side members for metallurgical and ceramic furnace according to any one of   previous claims, characterized in that the fixing means (7) consist of very long anchors, possibly in several pieces which are joined to their   common end by a possibly threaded ring (8), shaped like a "Christmas tree", the protruding parts (9) on the main rod serve as sealing lugs when pouring the concrete, one of the through ends is provided with compensation devices (9 ′) chosen in particular from -6- elastic washers.   Refractory lining of side members for metallurgical and ceramic furnace according to any one of   previous claims, characterized in that the ring (2) 5 comprises on its upper face (5) and over its entire periphery a   plurality of blind cavities (11), the lateral faces (17) of which are with negative spoils such as in particular of the dovetail type, these cavities being subsequently filled by the concrete (1) of the upper layer, thus providing anchoring points non-removable.   6 Refractory lining of side members for metallurgical and ceramic furnace according to any one of   previous claims, characterized in that the plate   lower (6 ') in ceramic fibers comprises on its surface a plurality of sealing members (10) for securing with   the layer (14) of material which covers it.   7 Refractory lining of side members for metallurgical and ceramic furnace according to any one of   previous claims, characterized in that the ring (2)   is made in the workshop by casting and molding of dense aluminous refractory concrete with large aggregates grading 35 to 70% alumina. 8 Refractory lining of side members for metallurgical and ceramic furnace according to any one of   previous claims, characterized in that the concrete block   upper refractory (1) of the assembly comprises, on the opposite face (16) of the products to be transported, a central recess (13) spanning the entire length.   9 Refractory lining of side members for metallurgical and ceramic furnace according to any one of   previous claims, characterized in that the faces   side of the ring (2) have blanks (12) cut in   bevel for deflection of slag.   7 - Refractory lining of side members for metallurgical and ceramic furnace according to any one of   previous claims, characterized in that the insulating material filling the hollowed-out space (3) is constituted either by a concrete, or by a stack of bricks capable of withstanding a temperature in the region of 1200 C.