GB2040423A - Improved refractory plate with metallic covering - Google Patents

Abstract

Sliding discharge gates for liquid metal containers have two apertured refractory plates in contact with one another and which slide one relative to the other to open and close the gate. In order to improve the support and fixing of the plates in the gate, at least one of the plates 20 has a sheet metal covering in the form of a shell 10 which covers only one face of the plate 20 and at least part of the sides 24 of the plate 20, the shell 10 having an aperture 12 which is at least as large as the aperture 21 in the plate 20. <IMAGE>

Description

SPECIFICATION Improved refractory brick with metallic coating In general terms, this invention relates to a refractory block with a metal covering, and more particularlythis invention relates to an apertured refractory block for a sliding discharge gate for discharging liquid metal from a container, for instance a ladle.

In general terms, a sliding discharge gate comprises two apertured refractory blocks or plates in contact with one another and which slide one rela tivetotheotherto open and close the gate. Normally, the apertures are in the centres of the blocks and one block is on top of the other. In the open position, the apertures are aligned and in the closed position, the apertures are not even partially superposed.

In order to prevent the passage of liquid metal when the gate is closed, the two blocks must have opposed surfaces which are in contact and preferably perfectly co-planar, and the surfaces should be pressed one against the other by a preferahly uniform and predetermined pressure. If this is not so, the liquid metal could penetrate between one block and the other, at first causing losses of liquid mental, and, when the liquid metal has cooled in the narrow spaces, the blockage of the gate, jeopardising the whole contents of the container of liquid metal.

In order to mount and support the blocks in the gate, relatively complicated and costly devices are used, and the proper mounting of the blocks requires a relatively long time.

The blocks wear out after a number of pourings, and must thus be replaced. During replacement, the container cannot be used, and thus one tries both to reduce the time required for replacing the blocks and one tries to extend the period during which one can use the blocks.

According to the present invention, at least one of the refractory blocks has a metal covering.

The subject of the present invention is constituted by an improved refractory brick with a metallic casing, particularly suitable for being used in sliding discharge gates.

It is known that in sliding discharge gates for ladles and the like it is arranged that two refractory material plates, apertured in the centre, slide one above the other in such a way as to pass from a position in which the two apertures are alligned (gate open position) up to a position in which the two said apertures are not even partially superposed (gate closed position).

It is apparent that the two bricks, in order to prevent the passage of liquid metal, when they are in the gate closed position, must have opposed surfaces which are perfectly coplanar and in contact, furthermore pressed one against the other by a uniform and predetermined pressure. If not, the liquid metal would succeed in penetrating between one refractory brick and the other, at first causing losses and, when said layer of liquid metal has cooled, the blockage of the gate, jeopardizing the whole contents of the ladle.

It follows that in order to support and fix such refractory bricks in the discharge gate of which they are a part, sophisticated and costly technical devicesare arranged which require a relatively long time for proper instailation.

At this point, one should remember that said bricks wear out after a certain number of pourings and are thus replaced: in such a case, the time required for replacing said refractory bricks forces the whole ladle to be put out of action and for this reason, on the one hand, one tries to reduce the time for replacing the bricks in question and on the other hand, one tries to extend the period of use of the bricks themselves in order to space out the replacements.

This aim is followed by the present invention by means of the use of a metal covering for the bricks in question.

In sliding discharge gates, the refractory bricks to which the invention relates must move one with respect to the other, and therefore the metallic casing, as well as concerning the whole of their surface, must satisfy severe robustness requirements. The essential characteristics of the invention are summarised and indicated in the Claims; the subject matter and advantages of the invention can be ascertained furthermore from the following description relating to embodiments which have been chosen solely by way of example, which description is made with particular reference to the attached sheets of drawings in which: Figures 1 and 2 are respectively a longitudinal section and a plan view of a metal covering for refractory bricks of a sliding discharge gate, according to a preferred embodiment of the invention; Figures 3 and 4 are a section and a view analogous to the previous one in which the protective brick is also inserted in the metallic casing; Figure 5 is a particular enlargement of a longitudinal section analogous to that illustrated in Figure 3, but it relates to a first variation of the embodiment; Figure 6 is an asymmetric view of a blocking element for a refractory brick inside its metallic covering;; Figure 7 is a detail further enlarged from FigureS; Figure 8 is a variation of the application of the detail already illustrated in Figure 6.

Figure 9 is a prospective view of a variant of the embodiment of the shell of the metallic casing of the refractory brick; Figure 10 is a variation of the elastic profile for fixing the refractory brick within the metallic shell illustrated in Figure 9; Figure 11 is a partial section analogous to that illustrated in Figures 7 and 8 but relating to the solution illustrated in Figures 9 and 10; Figure 12 is a variation of the embodiment of the elastic profile for fixing; Figure 13 is a longitudinal section of said profiled elastic along the plane XII-XII of Figure 12; Figure 14 is a longitudinal horizontal section along the plane XIV-XIV of Figure 12.

Referring particularly to Figures 1 to 4, the first embodiment of the claimed covering comprises a shell 10 formed by a base 11 (provided with a pas sage aperture 12) and two pairs of lateral sides 13 and 14. As it is possible to see from Figure 3 and Figure 4, the refractory brick 20 is inserted in the interior of the shell 10, which brick also has a central aperture 21 of a diameter clearly less than that of the aperture 12 in base of the shell 10.

The channel 22 provided on the base of the brick 20 provides a good connection with the remaining refractory elements of the gate and will not be further described because it has no direct relevance to the improvement which is the subject of the invention.

It is important to note that the thickness of the brick 20 is slightly greater than the height of the edges 13 and 14 of the shell 10: in fact, the free surface 23 of the brick 20, which is arranged to slide in contact with the free surface of a generally identical, opposed brick, should not be scratched or cut by the upper edges of the sides 13 and 14 of the second brick and the edges 13 and 14 of its own covering should not scratch or cut the face of the opposed refractory brick.

In order to hold the brick 20 and the shell 10 together, there is provided a thin layer of synthetic adhesive 24, which serves to guarantee the fixing of the brick 20 to the respective shell 10 during transport and mounting the same.

The use of an adhesive is found more convenient than a layer of refractory cement for avoiding the time lost for drying out that the use of the cement would have required when constructing the refractory brick. Besides, the use of the refractory cement would have introduced an arrangement which was continuous with the structure of the brick which, fol lowing the unavoidable differences in expansion coefficients of the two materials, could have caused cracking and a subsequent disintegration of the cement coating with the consequent possibilities of relative movement between the brick and the metallic shell.

In the embodiment illustrated in Figure 5 and in Figure 6, in place of an adhesive it is arranged that the connection between the shell 11 and the brick 20 is made by means of at least one pair of V-profiles 30, which are positioned in such a way that they can yield elastically, one on the short side of the shell and one on the long side of the same. It is apparent that in place of the two profiles of said type, one can use four of them, that is to say one on each side.

For this purpose, the internal dimensions of the covering 10 and the overall dimensions of the brick 20 are slightly different so as to allow the insertion of said elastic profile.

The profile 30 has an outer leaf 31, an inner leaf 32 and, on the latter, a flange 33 which is turned towards the inside of the shell 10 and is intended to bear against the upper face of a peripheral step 34 pre-formed on the free face 23 of the brick 20. In this way, with an abutment surface formed by the flange 33 of the elastic profile 30, one avoids the brick 20 being able to slip out of the shell 10. The elastic profile 30, as well as compensating for the unavoidable tolerances during fabrication between the dimensions of the brick and the dimensions of the shell 10, serves principally to absorb the different thermal expansions between the material of the brick and the steel of the shell 10.

In order to ensure that the elastic profile 30 remains fixed to the wall of the shell 10, in addition to the frictional force caused by the elastic flexing of the two leaves 31 and 32 of the profile 30, the variation of the embodiment illustrated in Figure 7 provides for the external leaf of the profile 30 to be welded, for instance by means of an electrical spotwelder to the sides 13, 14 of the shell 10 with welding points 35.

According to the variation of the embodiment illustrated in Figure 8, in place of spot-welding, the fixing of the profile 30 within the shell 10 is ensured by means of bending over the upper edge of the side 13 (14) of the shell 10 in such a way as to form a flange 36 which rests against the upper edge of the leaf 31 of the profile 30.

In the variation illustrated in Figures 9, 10 and 11, the metallic shell 110 has holes 50 in its sides 113 and 114.

According to this embodiment, the profile 30 is replaced buy a profile 130 formed by an angle piece whose vertical web 132 must be inserted between the edges of the metallic shell 110 on one side and the lateral surface of the refractory brick on the other side, as indicated in Figure 11.

The horizontal web 133 of the profile 130 rests in the way already described on the horizontal surface of the peripheral step 34 in the brick 20.

In order to fix the height of the elastic profile 130 with respect to the sides 113 or 114, respectively, of the shell 110, at regular intervals, the vertical web 132 of the profile 130 has some dimples 51 suitable to be inserted in the holes 50 in the walls 113 and 114 of the metallic shell 110.

In order to permit elastic horizontal positioning of the brick 20 relative to the metallic covering shell, according to the variation of the embodiment illustrated in Figures 12 to 14, as well as the dimples 51 arranged to lodge in said holes 50, the elastically yieldable profile 230 has a pair of longitudinal slits which define a thin elastic spring plate 53, also obtained by pressing, in the vertical web 232 of the profile.

The elastic spring plate 53 allows one to absorb the differences in elastic expansion between the metallic covering shell and the refractory brick to be covered while the sliding discharge gate is operative.

Although for reasons of description, the present invention has been based on that described and illustrated with particular reference to the attached sheets of drawings, many alterations and variations can be made to the embodiment of the discovery; such alterations and variations must all the same be considered as based on the following claims.

Claims (14)

1. Improved refractory brick, particularly suitable for a sliding discharge gate, for the type which has a metallic covering, characterised by the fact that said metallic covering is formed by a shell of sheet metal which embraces the lateral surfaces of the brick and only one of its faces.

2. Refractory brick according to the preceding Claim, characterised by the fact that the portion of metallic covering which covers the surface of the refractory brick extends heightwise for a distance less than the thickness of the refractory brick.

3. Refractory brick according to the preceding Claims, characterised by the fact that, according to a first embodiment, the connection between the walls of the refractory brick and the internal surfaces of the metallic shell is made by means of a thin layer of adhesive.

4. Refractory brick according to Claims 1 and 2, ,characterised by the fact that the connection between the walls of the refractory brick and the metallic covering shell is made by means of at least one pair of V-profiles inserted elastically between the lateral surfaces of the brick and the internal faces of the sides of the metallic covering shell.

5. Refractory brick according to Claim 4, characterised by the fact that said elastically yieldable V-profile has on its leaf nearer the refractory brick, a horizontal flange arranged to bear above a peripheral step preformed on the free face of the refractory brick.

6. Refractory brick according to Claim 4, characterised by the fact that the external leaf of the elastically yieldable V-profile, and particularly that leaf which is in contact with the internal faces of the sides of the metallic covering shell, is connected to said sides by means of spot welds.

7. Improved brick according to Claim 4, characterised by the fact that the outer leaf of the yieldable V-profile, and particularly that leaf which is in contact with the internal faces of the sides of the metallic shell, is restrained against relative vertical displace ments by means of a flange which is bent towards the inside of the metallic covering shell and prearranged on the upper edge of said shell.

8. Refractory brick according to Claims 1 and 2, characterised by the fact that the connection between the walls of the refractory brick and the metallic covering shell is made by means of at least one pair of L-profiles inserted between the lateral surfaces of the brick and the faces of the sides of the metallic covering shell; in which said sides are provided with suitably-spaced holes suitable for receiving corres ponding pressed protuberances preformed on the vertical web of the V-profile; in which furthermore the horizontal web of the L-profile bears against the horizontal surface of a peripheral step formed in the upper face of the refractory brick.

9. Refractory brick according to the preceding Claim, characterised by the fact that two parallel, opposed through slits are provided in a substantially central position on the vertical web of the L-profile; in which the strip between the two slits is, for exam ple by means of pressing, transformed into a leaf spring which is able to bear against the sides of the refractory brick.

10. Refractory brick according to the preceding Claims, substantially formed and put in operation according to that described and illustrated solely by way of example with particular reference to the attached sheets of drawings.

11. An apertured refractory block for a sliding discharge gate for discharging liquid metal from a container, the block having a covering of sheet metal which covers only one face of the block and at least part of the sides of the block, the covering having an aperture registering with, and at least as large as, the aperture in the block.

12. An apertured refractory block for a sliding discharge gate for discharging liquid metal from a container, the block being substantially as herein described with reference to, and as shown in, Figures 1 to 4, or Figures 5 and 6, or Figure 7, or Figure 8,orFigures9to 11,orFigures 12to 14Ofthe accompanying drawings.

13. A container for liquid metal, having a sliding discharge gate comprising two apertured refractory blocks in contact with one another and which slide one relative to the other to open and close the gate, at least one of the blocks being as claimed in any one of the preceding Claims, the face which is covered by the sheet metal covering being opposite to the face in contact with the other block.

14. A method of discharging liquid metal from a container as claimed in claim 13, one block being slid with respect to the other block to bring the apertures in the blocks into register, discharge being interupted by again sliding one block with respect to the other block to bring the apertures out of register.