CA1107499A

CA1107499A - Refractory structure

Info

Publication number: CA1107499A
Application number: CA270,183A
Authority: CA
Inventors: Hans R. Fehling; Horst W. Hase
Original assignee: Didier Werke AG
Current assignee: Didier Werke AG
Priority date: 1976-01-22
Filing date: 1977-01-21
Publication date: 1981-08-25
Also published as: JPH0131987B2; FR2369041A1; AR213543A1; SE434806B; GB1575601A; FI770200A; ES455230A1; FR2369041B1; SE7700661L; DE2702436B2; SE435146B; NL8801108A; DE2760353C2; LU76615A1; HU184077B; MX144963A; PL128817B1; CH614145A5; AR213542A1; JPS52110225A

Abstract

Abstract of the Disclosure A refractory structure comprising A) a body of cast refractory concrete material defining at least one discharge passage passing through the body and B) at least one reinforcing element located within the body or form-ing a face or faces thereof and interlocked mechanically with the refractory concrete which is juxtaposed to the refractory concrete or C) means defining at least one duct for a working fluid in the body or D) the discharge passage being defined by an insert of material embedded in the refractory concrete and having better wear resistance than the refractory concrete, or A), B) and C), or A), B) or C) and D) or A), B), C) and D).

Description

7~ 9 The invention relates to refractory bodies and finds particular use as wearing parts for use in the outlets of metallurgical vessels such as casting ladles and tundishes and as refrac~ory structures for use in outlet control devices 5. for such vessels and in particular sliding gate nozzle apparatus.
m e invention is described with particular reference to the casting of steel but the refractory wearing parts accordin~
to the invention are also applicable to the casting of other metals which cause considera~le wear because of their high 10. melting point or their corrosive ~ature.
Such apparatus comprises a stationary refractory upper plate defining a discharge passage and adapted to be located on the outside of the vessel in Juxtaposition to the outlet oriflce of the vessel, e.g. by being held in a metal frame attached to ; 15. the shell of the vessel, and a movable refractory sliding plate defining a discharge passage and mounted for movement between an open position in~ich the discharge passages o~ the two plates are in register and a closed position ln which the movable plate shuts o~f the discharge passage of the fixed plate.
20. Movement of the movable plate can be rotatory though a straig~t sliding motion is preferred.
One orm of such apparatus has a fixed upper plate and a mo~able lower plate. Such apparatus will be referred to hsrein as a two plate sliding gate nozzle apparatus. '~he movable plate 25. is preferably mounted for movement in a metal casing, and may incorporate an outlet nozzle or cooperate with one which is also movably mounted in the metal casing.
Another form of such apparatus has the movable plate mounted fcr movement between upper and lower fix~ed plates and 3~. is thus subs-tantia1iy parallel ~aced and the lo~er fixed plate KDNK/JP 2.

' P74~9 incorporates or cooperates with an outlet nozzle. Such apparatus will be referred to as a three plate sliding gate nozzle apparatus.
Conventional refractory plates and nozzles for use in such apparatus are made by pressing a refractory granular mass and then firing it at high temperature and then drilling out the outlet passage.
Refractory wearing parts of the described kind are exposed in use to widely varying thermal stresses. On the one hand such refractory wearing parts are exposed during the pour to very high temperatures at which metals have a major corrosive and erosive action on refractory materials. On the other hand such refractory wearing parts are exposed at the start of the pour to an unusually severe and sudden thermal shock which gives rise to correspondingly high mechanical stresses due to differential thermal expansion. For both these reasons the service life of known refractory wearing parts of the kind contemplated is short. For example, on average a sliding plate requires replacement after only two pours, representing, for example, a total casting time of only two hours.
According to the present invention, there is provided a reractory structure comprising a body of refractory concrete material defining at least one discharge passage for molten metal passing through the body and at least one reinforcing element located within the body or forming a face or faces thereof and interlocked mechanically with the refractory concrete with which it is in intimate contact over the whole of any of the surface of the reinforcing element which is juxtaposed to the refrac-tory concrete, the reinforcing element being separated by refractory con-crete material from any surface of the refractory structure which contacts the molten metal in use.
Also according to the invention there is provided a process for making a refractory structure which comprises providing a mold defining the external shape required for the component, locating in the mold at least one reinforcing element so shaped as to be able to mechanically interlock 3.

~7~9 with the refractory concrete and means defining a discharge passage, pour-ing a cold curing, cold setting refractory concrete composition into the mold around the reinforcing element in such a way that the concrete mechani-cally i.nterlocks with the reinforcing element when it has set, and the discharge passage defining means, compacting the concrete, levelling the concrete in the mold, allowing it to set and removing it from the mold before or after allowing it to cure, and drying the concrete.
The reinforcing element is referred to as being interlocked mechanically with the refractory concrete. It is to be understood that this means not only arrangements in which the interlock is such that the cast refractory concrete body and the reinforcing element cannot be separated without breaking one or other of these components, but also arrangements in which the interlock is at least operative in the situation in which the structure is actually used so as to resist separation of the components at least so far as shear forces in the principal plane of the structure are concerned.
Thus when the structure is in the form of a plate in a sliding gate nozzle it is held in compression in use, both at its edges and at its opposed principal faces. lt is thus only essential that the mechanical interlock is sufficient to resist separation of the cast concrete body from the reinforcing element in a direction parallel to the principal plane of the plate. However arrangements in which the components are inseparably attached to each other are preferred.
Preferably there i.s at least one duct in the refractory concrete for the circulation therethrough of a working medium such as a heating or cooling flui.d.
By appropriately controlling the supply of heating and cooling fluid it is possible for example to raise the temperature of the refractory wearing part prior to the start of a pour sufficiently to obviate the material being damaged by the temperature shock at the start ~ ~.

79L~`g of the pour. During the pour the temperature peaks which otherwise arise in the wall of the passage may be reduced to an acceptable level by intro-ducing a coolant for a suitable period of time. In this way, on the one hand, temperature changes can be made to proceed gradually and, on the other hand, the temperature peaks to which the refractory part is exposed can be limited to a level at whïch the service life of the part will be increased.
In a preferred form of the invention the refractory structure is in the form of a plate, the discharge passage being transverse to the major plane of the plate and the ducts being at least partially and preferably substantially parallel to the principal plane of the plate.
Preferably the ratio of the maximum longitudinal dimension of the sliding surface of the plate to the minimum thickness of the plate is in the range of ratios of 25:1 to 7.5:1 and more preferably 20:1 to 10:1 and especially 15:1 to 10:1.
In a preferred form of the invention the ducts are tortuous.
The term "tortuous duct" covers any duct which undergoes 5.
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7~ 9 a change of direc-tion in its passage from its commencement at an inlet aperture to the body to its emergence at a~
outlet aperture to the body. These ducts may have a circular or non-circular cross section, such as a rectangular, 5. oval or other cross section. Parts of the ducts may be-curved, others straight and they may intercommunicate at an angle, for instance at a right angle. The ducts may be formed by metal or ceramic or other heat resistant tubes incorporated in the refractory wearing parts. Preferably at least the 10. entry to a duct is formed by a metal insert to facilitate connection of the ducts to a supply of working fluid.
In another embodiment of the invention the re~ractory wearing part is of two-part construction, preferably being divided in a parting plane parallel to its principal plane 15. and one of the components of the plate contains the duct or ducts with one open side in such a way that when combined with the other plate component or cover the open side of the duct or ducts is closed.
The cover is preferably fl-~sh with the surface of the 20. plate which rnay have parallel principal surfaces. Preferably the inner edge of the cover is spaced away from the edges of the discharge opening. It may consist of refractory material, e.g. a ceramic or of steel.
The openings of the duct or ducts may be in the cover.
25. Alternatively the inlet and outlet openings may be for~ned in the sides or ends of the plate. It is desirable that at least the inlet opening of the ducts should be formed by a metal insert to facilitate connecting the duct to a gas or liquid supply.
30. Refractory wearing parts according to the invention may KDNK/JP 6.

be produced by pouring a refractory concrete into an appropriate mould, means de-termining the duct or ducts of desired cross section being disposed in the desired position inside the mould before the concrete is poured.
5. The means used for forming the duct or ducts may, if this is desirable, be o~ a temporary nature, for instance they may consist of a combustible material such as paper or synthetic plastics material, so that they can be removed by heating before the refractory wearing part is used for the first time, or may 10. be such that their removal during first use will not result in a restriction of the duct cross section. Alternatively the means may also consist o~ a removable solid material that possesses the desired shape of the duct and that is inserted in the mould (as a core) and removed after the refractory part has been 15. moulded, for instance they may consist of a combustible material such as paper or synthetic plastics material, so that they can be removed by heating before the refractory wearing part is used for the first time, or may be such that their removal during ~irst use will not result in a restriction 20. of the duct cross section. Alternatively the means may also consist of a removable solid material that possesses the desired shape o~ the duct and that is inserted in the mould (as a core) and removed after the refractory part has been moulded, for instance by the application of heat, ~or instance by making 25. such a core of a low melting alloy, such as a tin alloy or Rose's metal. This has the advantage of permitting ducts OI
non-circular cross section to be easily produced. Alternatively the duct or ducts may be formed of heat resistant metal or ceramic tubes or pipes.
30. Preferably the duc-ts are so shaped that they embrace KD~K/JP 7.

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the discharge passage traversing thç sliding plate by surrounding the sarne in at least 180 arc and preferably in a 360~ circle. In plates having asymmetrically disposed discharge passages the ducts will with advantage run at 5. least from the middle, preferably from the remote end of the plate in an at least 180 arc around the discharge passage and then preferably extend back again at least to the middle and preferably to the same end of the plate.
The inlet openings into ducts surrounding the discharge 10. passage are preferably tangentially disposed to the circle to facilitate circulation of the working fluid which may be heating or cooling fluid.
The heating fluid and the cooling fluid are preferably gaseous. With advantage a heating fluid may be a comb~stion 15. gas, whereas the coolant may with advantage be compressed air.
The invention also extends to a method of conditioning, particularly sliding plates in sliding gate nozzles for vessels containing molten metal, which is characterised in that heating fluids and/or cooling fluids are circulated through at least 20. one duct contained in the sliding plate.

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The invention also relates to reXractory structures containing a gas-permeable insert and adapted for use in or with ; 25. a vessel which is itself adapted to contain molten metal, parti-cularly for discharge control means on vessels adapted to contain a metal melt.
Refractory structures incorporating gas-permeable inserts have been described for example in German Pat. Specn. No. 1935401, 30. German Pat. Specn. No. 2019550, and German as~filed Patent Specn.
No. 2218155.
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~$~74~g The purposes of the gas-permeable inserts include that of permitting major volumes of a gas to be introduced under pressure into the space or cross section provided for the discharge of the metal melt.
5. ~en such gas-permeable inserts are provided in conventional fired refractory plates or nozzles they must be inserted into pre-bored holes and not inconsiderable difficulties arise, particularly in quantity production, in firmly securing them in their holes and in making suitable 10. arrangements for the supply of the gas.
It is an object of the invention to avoid these draw-backs and to provide more simply a refractory component of the kind contemplated above. In the present invention this object ~s achieved by embedding the gas-permeable insert in 15. refractory concrete from which the refractory component is formed.
The gas-permeable porous insert is embedded preferabl-y directly, in the body of refractory concrete, for instance by pouring and vibrating the concrete around the insert. Ducts 20. for working fluid communicating with the gas permeable insert may be formed in the in the refractory concrete. However, if desired, the insert may be previously located in a metal surround in such a way that a cavity remains between an inner face of the insert and the refractory concrete body, the gas supply 25. means, for instance a duct moulded into the concrete opening into this cavity. The ducts extends preferably to a remote end face o~ the component. In the case of a sleeve (nozzle brick) containing a central metal discharge passage or of the fixed plate of a 2 plate sliding gate nozzle, the gas-permeable insert 30. may with advantage extend to the wall of the metal discharge KDNK/JP 9.
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7~g passage traversin~ the par-t and may encompass the entire periphery of this passage, thus itself forming the wall of this passage.
With a sliding plate Ior a t~Jo plate sliding gate 5. nozzle (i.e. comprising one fixed and one movable plate), the gas-permeable insert is preferably located in the sliding plate and flush with the top face of the lat-ter so ; as to be below the discharge passage of the fixed plate when the gate is shut. The insert may be adap-ted to be supplied 10. with gas via a duct extending from one end or side wall of the plate or the bottom face of the plateO
When the inlet is in the bottom face of the sliding plate of a three-plate sliding gate (i.e. having two fixed plates and one movable plate in the middle), access thereto ~or the 15. gas may be obtained via a duct in the lower fixed plate. This duct is preferably formed in a ca.st refractory concrete plate as des~ribed above.
The use of gas-permeable inser-ts which are embedded in a refractory component of a 2- or 3-plate sliding gate nozzle 20. made of refractory concrete is of particular importance in preventing the gates from becoming inoperative by the molten metal freezing in the discharge passage above the closed sliding plate. The gas preferably used is an inert gas, such as argon or nitrogen.
25. The form of construction according to the invention in which a gas-permeable or porous insert is embedded in a - refractory part made of refractory concrete~ for ins-tance by pouring and possibly compacting the concreteS e.g. by vibration, around the insert, provides an oustandingly reliable bond bet~een ~0~ the gas-permeable insert and the refractory concrete and - .YDNK/JP

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s~rprisingly there is no significant impairment of the permeability to gas of the gas-permeable or porous insert.
The gas-perrneable insert and -the ducts for the working fluid may be loca-ted on a metal plate which is flush with ~; 5. the underface o~ the sliding or middle plate.
The working fluid may be conducted to the gas-permeable insert through an opening in the metal plate in the bottom of the sliding pla'ce, which opening communicates with a recess in the upper surface of the bottom fixed plate, and the recess 10. may be connected to an external gas supply pipe.
Alternatively the working fluid may be conducted to the gas-permeable insert through an opening in the upper surface of the sliding plate, which opening communicates with a recess in the undersurface of the upper fixed plate, and the 15. recess may be connected to an external gas supply pipe.
The length of the recess is preferab]y so calculated and its position so chosen that the closing movement of the sliding plate uncovers the gas admission from the recess -to the gas-permeable insert when the insert 1s in the working position 20. in the metal discharge passage, and the opening movement of the sliding plate shuts off the gas supply when the gas-perrneable insert withdraws from the discharge passage and the latter is opened for the discharge there-through of mol-ten me-tal.
The invention also extends to cases where the refractory 25. component is in the forrn of a sleeve or nozzle brick for lining the well brick of a metallurgical vessel.
The gas-permeable insert may be itself sleeve-shaped and embedded in the middle of the sleeve. The gas-permeable insert preferably inserted into a sleeve shaped sheet rnetal surround ~ ~0. before being embedded, so that a clearance remains bet~leen the `~ outside periphery of the insert and the inside sur~ace of the KDN~/JP 11.

metal surround, which clearance serves as a gas distributing chamber.
The invention also extends to a method of producing a nozzle bricl~ in accordance with the inventlon in which the 5. concrete pouring rnould comprises an outer form and a central core for holding the gas~permeable insert in the desired position inside the mould. In a preferred form of the invention a jacket conforming with the shape of the form and consisting of a fire-resistant felt is introduced into the form before 10. pouring begins, and is then firmly bonded to ~e refractory component.
The gas-permeable insert is preferably soaked with water before the concrete is poured.
As mentioned above the invention relates to sliding gate 15. nozzles for vessels adapted to contain molten rnetal, parti~
cularly steel casting ladles and tundishes for the continuous casting of steel.
; In such sliding gate nozzles thermal stresses (i.e.
mechanical stresses due to differen-tial thermal expansion) 20. often arise for which it is very difficult to compensate.
In addition, high thrusts are encountered. These may jointly give rise to bending and tensile stresses o~ a sev~rity -~rhich the refractory material of the nozzle plates cannot withstand.
The conditions are unlike those when refractory components 25~ and parts are purely statically loaded such as occur in furrlace walls or roofs. There it is fairly easy to,make allowance for any possible thermal stresses and strains~ Tensile stresses can be largely avoided and dynamic thrusts do not arise.
- In conven-tional sliding gate nozzles -the above merltioned , .
~ 30. severe stresses are in practice absorbed by errlbedding the . , .

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refractory material in the metal supporting structures of the gate in a densely compacted layer of mortar which makes all-over close surface contact with the re~ractory plate and the supporting structure. This generally accepted 5. solution of the problem is technically satisfactory, provided it is properly applied. However, it requires skilled manual work and the functional reliability of the gate depends upon this work having been carried out with repeatably uniform precision. The dependence of operating safety upon purely 10. human factors is a major defect, bearing in mind the frequency with which the wearing material in sliding gates requires replacement and the danger of a serious steel leakage. An additional factor is that the service life of the refractoy material located by embodiment in mortar is relatively short~
15. particularly in the case of the orificed plates used for controlling such sliding gate nozzles as mentioned above.
It is an object of this aspect of the present invention to provide a sliding gate nozzle ~or vessels adapted to contain ; a metal melt, wherein the above described defects are at least ; 20. reduced in severity.
; This aspect of the invention relates to a sliding gate nozzle for vessels adapted to contain metal melts cornprising at least one fixed and one movable plate, at least one of the plates being associated with a supporting frame and each plate having 25. an orifice for the passage therethrough of the metal melt, characterised in that ~ least the movable sliding plate consists - substantially of re~rac-tory concrete and on its side facing away from its sliding face is provided with a metal reinforcement ernbedded therein without the use of mortar, said reinforcement 30. being thus anchored in the sliding plate so that tension, : , KDNK/JP 13.

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compression or shear forces cannot shift it, the sliding plate itself being located in the supporting frarne without the use of mortar and the likewise movable supporting frame and the reinforcement preferably incorporating elements for 5. transmitting the thrusts when the gate is operated.
- The reinforcement preferably substantially comprises a metal sheet or a metal plate provided with elements firmly fitted thereto and projecting out o~ its principal plane~ the said elements creating the non-shift anchorage of the rein-10. forcement in the sliding plate against tensile and breaking ~` forces or thrusts.
The elements projecting out of the principal plane of thereinforcement may be tabs integrally formed with the sheet ;' metal or metal plate of the reinforcement and bent to embrace ; 15. the sides and ends of the sliding plate. Alternatively the elements projecting from the principal plane of the rein~orcement may be parts that have been bent out of the reinforcement plate ; itself.
In another alternative the elements projecting from 20. the principal plane of the reinforcem0nt may be indentations - or corrugations formed in the sheet metal reinforcement or the reinforcement plate. In yet another al-ternative the ; elements projecting frorn the principal plane of the reinforcement may be projections such as pins welded to the sheet metal , 25. reinforcement or reinforcement plate. In a further alterna-tive the sheet metal reinforcement or the reinforcement plate may be perforated~
The elemen-ts for transmitting the thrusts which arise when the gate is opera-ted may comprise a'~utment or elevations jl.,,,~, , ~ 30. on either side of the discharge passage of the molten metal . ~ , KDNK/JP 14.

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through the supporting ~rame, said abutments cooperating with shoulders fortned by the reinforcement.
The abutments on the supporting fr~me may extend across the direction of movement of the sliding plate and may 5~ consist of ribs extending a dis-tance corresponding to the width of the sl~ding plate and each cooperating with a complementary shoulder formed by the reinforcement.
The elements on the supporting frame transmitting the thrusts which arise when the gate is operated may comprise 10. a pin provided at leas-t at one point spaced away from the discharge passage for the molten metal, said pin engaging a reinforcemen-t socket in the sliding plate.
The reinforcement may rest on three and preferably six bearing abutments on -the facing surface of the SUppOrtiIlg 15. frame.
Preferably at least three and preferably four of the bearing abu-tments are disposed symmetrically at a distance about the discharge passage for the molten metal, so that the sliding plate can freely bend slightly in the axial direction in -the region 20. surrounding the orifice.
The reinforcement contains an opening in the region of the discharge passage of the mol-ten metal through the sliding ~- plate, and this opening preferably has a diameter exceeding the diame-ter of the orifice, e.g. by an amount in the range of 25. 120 to 300yo, .~

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The inven-tion may be put into practice in various ways ; and certain specific embodiment;s will be described by way of example to illustrate the invention with reference +o the accompanying drawings in which:
5. Figure 1 is a diagrammatic cross sectional view taken on the line I - I of Figure 2 of the middle plate of a three-plate sliding gate nozzle apparatus containing a duct formed therein in accordance with a f1rst embodiment of the inven-tion~
Fig~lre 2 is a cross sectional view of the plate 9 taken . . .
10. on the line II II of Figure 1~
Figure 3 is a diagrammatic plan view of a second embodi-. ment of a middle plate in accordance with the invention con-; talning a duct forrned therein and a porous insext) Figure 4 is a cross sectional view of the plate in 15. Figure 3 taken on the ~ine IV - IV of Figure 3J
Figure 5 is a cross sectional view of a modification of l the embodiment shown in Figures 3 and 4 taken on the line I V - V of Figure 6 Figure 6 is a diagrammatic cross sectional view taken on .
20. the line VI - VI of Figure 5 of the middle pla-te and of a partial plan view of the bottom plate of the embodiment shown in Figure 5 .. ..
. Figure 7 is a diagrammatic cross sectional view taken `~ on line VII - VII of Figure 8 of a third embodiment of a middle 25. plate in accordance with the invention Figure 8 is a cross sectional view of the plate shown in Figure 7 taken on the line VIII - VIII of Figure 7 Figure 9 is a diag~rammatic cros~ sectional view taken on the longitudinal cent.re :Line of a fourth em~odiment of a ~- 30. middle pLate and of part of the bottom sta-tionary plate in KDNK/JP l~ ~

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accordance with the present invention, ; Figure 10 is a cross sec-tional view of the embodiment sho~m in Figure 9, taken on the line ~ - X of Figure 9, Figure 11 is a diagrammatic plan view of the upper surface 5. of the bottom stationary plate of the embodiment shown in Figure 9, Figure 12 is a dlagrammatic cross sectional view frorn above . taken on the line XIV - XIV in Figure 13 of a fi~th embodiment -~ of a middle plate in a three-plate sliding ga-te nozzle apparatus, 10. provided with a duct that can be d.irectly heated9 Figure 13 is a sectional view of -the plate shown in Figuxe 12 taken on the line XIII - XIII in Figure 12~
Figure 14 i5 a diagrarnmatic cross sectional view of a sixth émbodiment of a middle plate of a 3-plate sliding gate 15. nozzle apparatus containing a gas-permeable insert embedd~d therein in accordance with the present invention, Figure 15 is a plan view of the plate show~ in Figure 14, Figure 16 is a cross sectional view of a 3-plate sliding gate nozzle apparatus for a vessel adapted to hold a metal mel.t . 20. showing a seventh embodiment of a middle plate in accordance ~ with the invention which incorporates a gas-permeable lnsert embedded in the plate which is shown in the open position, Figure 17 is a Gross sectional view corresponding to Figure 16 showing the middle or sliding plate in the partly . 25. closed positîon, Figure 18 is a cross sectional view corresponding to Figure 16 showing the middle sliding plate in the closed position, Figure 19 is a cross sectional view of a 2-plate sliding gate nozzle apparatus incorporating an eighth embodiment of 30. the invention namely a sliding plate ha.ving a gas-permeable l~rl)NK/J'P 1~

a~ g insert embedded thereir.t, Figure 20 is a cross secti.onal view of a ninth embodiment .' of the invention, namely a nozzle containing a gas-permeable insert in the metal dis~harge passage of a vessel adapted to 5. hold a metal melt;
Figure 21 is a diagra~natic sectional view demonstrating the way in which the embodiment shown in Figure 20 can be produced, Figure 22 is a cross sectional view taken on the line 10. XXll - XXIX of Figure 21 of the gas permeable ir.tser-t shown .. in Figure 21, Figure 23 is a diagrammatic cross sectional view of a . tenth embodiment of the invention exemplified by a sliding plate containing a metal reinforcement;
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15. Figure 24 i~ a view similar to Figure 23 showing a mod.i.~:.ied form of construction, Figure 25 i.s a plan view of an eleventh embodiMent of . l I the invention, :. Figure 26 is a longi-tudinal sectional view of the embodi-20. ment showrn in Figure 25, .. Figure 27 is a longitudinal sectional view of a twelth embodirnent of the i~vention, Figure 28 is a longitudinal sectlonal v.iew of a thirteenth embodirnent of -the inventionJ
25. Fi.gure 29 is a longitudinal sect;ional view of a fourteenth em~odiment of the invention, Figure ~0 is a longitudinal sectional view of a ~ifteenth embodment of the invention, , Figure 31 is a longi-tudinal sectional view of a sixteen~th 30. embodirnent of the invention, KDNK/JP / p 74~g Figure 32 is a view of the embodiment shown in Figure 31 seen from a~ove, Figure 33 is a cross sectional view on the line XXXIII
XXXIII of Figure ~2, 5. Figure 34 is a view of a seventeenth embodiment of the invention seen from above, Figure 35 and 36 illustrate one way of producing a sliding plate provided with a metal reinforcement 9 and Figures 37, 38 and 39 illustrate another way of producing 10. a sliding plate provided with a metal reinforcemen-t.
F'gures 1 and 2 illustrate a middle plate 112 o~ a COfl-ventional three-plate sliding ga-te nozzle apparatus. Other parts of the apparatus are not shown since sliding gates as such are kno~.
15. A duct 150 for conducting a gas or a liquid extends ~rom an inlet opening 151 roughly in the middle of one of the longer sides around a discharge passage 106 to an outlet opening 152 in the other longer side.
In an alternative arrangement(indicated by a dot-dash line 20. 153) the duct 150 may extend further around the discharge passage 106.
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In yet another alternative the duct ope~ings 151 and 152 ' ~ may be formed in one end of the plate 112, preferably at the end where the mechanism for actuating the pla~e is located.
25. The duct 150 is preferably formed in the upper half of the plate 112, i.e. in that half which faces the metal rnelt, for i example at a height equal to 20 to 50% of the thickness of the ;~ plate measured from the upper surface 141 of the plate 112.
The plate 112 is made of-refractory concrete suitable I 30. compositions ~or which are given in E~amples 1, 2 and 3 be]ow.
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The duct 150 is formed for example by the provision of a steel tube in the mould and the refrac-tory concrete is poured around the tube. The concrete is then allowed to set, for example for 12 hours, and the plate is then taken out of 5. the mould and allowed fully to harden for another 48 hours at room temperature~
Instead of providing a steel tube a consumab]e material may be used to form the duct. Thus a tube made of cardboard or ; of a synthetic plastics material can be used which burns away 10. when casting begins. Alt~ natively a core of lo~ melting metal, such as ~ERROBEPil)~ an alloy of tin, or Rose's metal can be used.
This has the advantage that non-circular ducts of any desired ; cross section, such as rectangular or oval cross sections can be easily produced.
15. The CERROBEND material can be removed by the application of heat, for instance during the process of drying the plate.
The alloy will then melt and run out, a process that can be accelerated by blowing low pressure steam through the duct.
The discharge passage 106 may be bored through the cured 20. concrete either with a diamond tool or preferably this passage is moulded during the pouring of the concrete by pro~iding a removable core, and if the passage is cylindrical the core may be of split construction to facilita-te its ex-traction.
Figures ~ and 4 illustrate a modified form of construction 25. of a rniddle plate 112 containing a cooling duct or heating duct 150 and a porous or gas-permeable insert 156.
The plate 112 is composed of two component parts, namely a body component 160 and a separate cover plate 161 for the duc-t.
The body component 160 is first produced, as above described with 30. reference to Figures ] and 2, by pouring the concrete into a mould which forms the duct 150, in the present instance formin~
KDNK/JP ~ J~ k an open groove and rebated ledges 162 and 163 for ihe cover 161.
The ledge 163 adjoins another recessed portion 164 which penetrates to a greater depth into the body component part 160 for the purpose of creating a gas distributing chamber surrounding 5c a porous and gas-permeable insert 156. The height of the inser-t 156 is preferably :lightly less than the depth of the ledge 163 so that a clearance 167 remains between the cover 161 and the inner face of the insert 156.
The cover 161 may be separately made of the same material 10. as the body component 160 and it may be cemented into position with the same refractory concrete (as indicated at 168). The cover 161 may be reinforced by casting a metal plat.e into the same.
Alternatively, for some applica-tions where differences in 15. thermal expansion are not very serious, a steel cover, pre~er~bly of stainless steel, might also be used.
The disbharge passage 106 and the inlet 151 and outlet 152 may be produced in the same way as'described with reference to Figures 1 and 2. Alternatively they may be holes in the body 20. component 160 drilled with a diamond drill.
External valve means are preferably provided for the purpose of allowing a gas e.g. air or nitrogen to enter through the inlet 151 and to leave through -the outlet 152 when the sliding gate is open, escape through the insert 156 being preven-ted . by the upper ~ plate (not shown), and in the closed position of the gate to enable the outle-t 152 to be closed and to cause a gas preferably argon to be diverted -to the insert '56 whence it escapes through the discharge passage ln the upper stationary pla-te and enters the molten metal.
30. In an alternative embodiment the inlet and ou-tlet openings~

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as in~dicated at 170 and 171, may be formed in ~,he cover 161 and arranged to communicate with the gas supply and return ` through suitably located grooves in the bottom stationary plate ,., (not shown). Such an arrangement will be described in greater 5. detail with reference to Figures 9 to 11. A special form OI
this arrangement for an outlet is illustrated in Figures 5 and ~.
:' In this instance the outlet 171 from the plate 112 is formed , ;~' in the cover 161 and leads across the undersurface of the plate .
. 112 to the outside. The outlet 171 comrnunicates with a 1021gi~
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','' 10. .tudinal groove 1'72 in the upper surface of the bottom stationary ,;:' plate 111~ en the middle plate 112 is in the casting,position ', (open position) one end 173 of the groove 172 extends beyond ,' the end of plate 112 thereby permitting the hot gas from the duct 150 to e~cap~ from the end 173 of ~he groove 172 in the 15. bottom plate 111. At -the same time the length of the groove 172 is so determined that when plate 112 is moved from its open into its clo.sed position, the groove 172 will be completely covered by plate 112 and the gas in the duct 150 will be forced '~ ' to pass through the porous or gas-permeable insert 156 into the 20. melt in the metallurgical vessel. This form of construct.ion clearly has the advantage of greater simplicity compared with the arrangement in Figures ~ and 4 and of providing au1;oma-tic control i. of the gas.
Figures 7 and 8 illustrate a modified form of the construc 25. tion of Figures 1 and 2, which includes a porous or gas-permeable - insert 156. In this arrangement the middle plate 112 contains an insert 175 made of a normal ceramic material or of steel (ordinary or stainless steel) at the end 142 of the longer side of the plate~ This .~acilitates the provision of the parts required 300 for the gas supply connection and it also serves as a support KDNK/JP

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for the porous insert 156 and the core for the duct 150 during production of the plate, both being secured, for example, with a mastic, to the plate 112 whilst the concrete is being poured into the mould. The duct 150 extends.into the proximi-ty of the 5. discharge passage 106 or in another form of construction it embraces the same as indicated at 153.
The duct 150 is flattish and extends at a level which is between 20% and 80,' of the thickness of the plate 112 away from its upper face 141. The porous insert 156 is rectangular and 10. disposed between the arms of -the duct 150.
In thi.s form of construction the above-described CERR03END
material may be used. The insertion 175 is placed on the bottorn of the mould, the CERROBEND core defining the shape of duct 150 is ~ormed and the porous 7 nsert 156 so located between the arms 15. of the duct that the CE~OBEND material prevents the liquid refractory concrete .~rom penetrating .tnto the porous insert 156.
The concrete mass is then poured into -the mould. After the casting ha.s set and has been removed and allowed to cure the CE M OBEND material is removed by heating or by blowing it out 20. with steam.
The discharge passage 106 i.s produced as has been described above and the upper and bottom surfaces o~ the plate are machined - should this be necessary.
Figures 9 to 11 show another form of construction of the 25. three~plate sliding gate in~hich the middle plate 112 as well as the bottom stationary plate 111 are of somewhat different construction~
A porous insert 156 i5 located in -the longer part of .~ the middle plate 112 and supplied with gas from a pipe 180 - 30. through an upwardly recessed opening 181 in the insert 156.
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.~ The insert 156 an~ the pipe 180 are located on a metal plate - -;
182 which has an opening 188 opposite to a corresponding opening 189 pointing downwards at the end of the pipe 180. A metal pipe 184 is provided inside the plate 112 transversely there-::- 5. to between the insert ].56 and the discharge passage -1.06 and this ., has an entry 185 and an outlet 186 both pointing do~wards, 185 communicating with duct 184a and 186 with 184b which have operi.ngs in the undersurface of plate 112.
As will be apparent from Figures 10 and 11 the bot-tom 10. stationary plate 111 is provided with two parallel groove.s 190 and 191 in its upper face which are covered by the lower face of the plate 1].2 and serve as gas ducts. The groove 190 exter1ds ;~. from a metal or ceramic inserted component 192 serving as an inlet to the end of the plate 111 where it communicates with a 15. cross groove 193 extending only across about half the wi~th o~
',!' the plate 111. The other groove 191 exterds from a point faclng groove 193 to an outlet 194. In the open position. of -Lhe plates 111 and 112 the cold gas is flGwing through the opening 192~ the groove lgo and the opening 184a into the cooling tube 18~ from 20. whence it passes at the other end through the opening 184b and the groove 191 to the outlet 194, through which the hot gas having cooled the plate can freely and safely blow of~ into the :: atmosphere.
The pipe 180 is so disposed that when the plates 111 and 25. 112 are in the closed positior, (corresponding to a movement ~ of the sliding plate 112 from left to right),the opening 188 : communicates with groove 193 and gas will be conducted from t.he entry 192 through the insert 156. The pipe -184 in this positi.on . is closed~
30. In Figures 12 and 13 the mi.ddle plate 112 has a cer.tral . KDNK/JP
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flattened duct 260 which reaches frorn one end-of the plate 112 into the proximi'cy of the dischar~e passage 106 where it divides into -two oval ducts 261 and 262 that embrace -the discharge pas,~age ]o6 and have outlet,s at the other end o~ the 5. plate 112. A burner nozzle 264 (or an air lance) is inserted into the entry opening of the flattened duct 160, permitting the plate 112 to be heated by hot combustion gases. When an air lance is used the plate 1]2 can be cooled by compressec1 air being blo~m through the pla-te.
; 10. Although not shown in the drawings the entry openings into the duct or ducts in a preferred form of construction may tangentially co~municate with the ducts to improve circulation of the heating or cooling fluid. This arrangement is parti-cularly useful when the duct or ducts surround the discharge 15~ passage.
Examples of refractory concretes are hereunder given, such as may be used for the wearing parts that have been described above, and for making refractory parts provlded with gas-I permeable inserts, particularly for parts of sliding gate nozzles ; 20. associated with vessels holding molten metal.
~ e 1 80% by weight of an aggregate containing 40yo by weight of A120~ and having a particle siæe from 0 to 5 mm are mixed with 20% by weight of a fused alumina cement having a content of 25. 40% by weight of A1203, 12 litres of water being added in respect of each 100 kg of the dry mix.
- ~or the production of a wearing par-t this mix is poured into a mould and compacted by vibra-tion should thiS be desirable, After having sufficiently set the concrete part is taken ou-t of 30. the mould, stored to cure and dried.
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80% by weight of Guyana-bauxite contai.ning 88So by weight of A120~ particle size 0 to 5 mm was mixed with 20C~o by weight of alumina cement containing 70~ by weigh-t of A120~
5. and 10 litres of water per 100 kg of dry mix. This mix is . further processed as described in Example 1.
However, if the plates are tobe used for casting steels having melting points above 1500C which are cast at ternperatures - 50C to 60C above their melting polnts, the conditions 10. which the plates have to withstand are very much more severe and ln order -to ensure a more reliable service special compo-..:
sitions must be used.
These conditions consist in a very severe mechanical erosive and chemical corrosive attack on the edges of the dis-15. charge passages of theplates combined with extreme thermal shock, the plates before the pour starts having a tempera-ture of only 200C to 300C.
For such very severe conditions it is preferred to use ~:~ refractory concretes containing from 5 to 8% by weight of an 20. alumina cement, 2.5 to 4% by weight of a pulverent refractory ~-; material (having a particle size of less than 50 microns and i pr~ferably less than ]. micron) such as a kaolin or bentonite, micronised silica, micronised alumina, micronised magnesia, micronised chromite or micronised fosterite, 0.01 to 0.30~
...
: 25. by weight of an agent effective to increase the flowability of the composit.ion comprising an alkali metal phosphate, al~ali metal poly~hosphate 7 alkali me-tal carbonate, alkali metal carboxylate or alkali metal humate and from 87.7 to 92,~ by weight of at least one refractory aggregate~ desirably having 30. a particle size not exceeding 30 mm, and desirably all of which KDNK/JP

pass.a 10 mm mesh and about 25~o of which pass an 0~5 mm mesh screen. The refractory aggregate may consist of calcined refractory clay~ bauxite, cyanite, sillimanite, andalusite, cor~dum, tabular alumina, silicon carbide, 5. magnesia, chromite or zircon or mixtures thereof.
An example of such a concrete is given below:
.. , ~
87.8 to 92~o by weight of tabular alumina, particle size 0 - 6 mm are mixed with 5 to 8% by weight of alumina cement containing 10. about 80% by weight of A1203, 2;5 _ 4G/o by weight of micronised alumina and 0~01 to 0.3% by weight of alkali metal poly-phosphate. 5 litres of water are added per 100 kg of dry mix.
The mix is poured into the mould and can be compacted by vibration.
15. Figures 14 and 15 illustrate the sliding or middle plate 112 of` refractory concrete of a 3-plate sliding gate nozzle apparatus in which a gas-permeable insert 156 ~s embedded.
The insert 156 may be a porous body consisting of a coarse-grained rnass of corundum or mullite sintered with a small quanti-ky 20. of a cernenting agent and exhibiting a gas-permeability of at least 100 nanoperms.
The principal component of the sliding plate 112 is a pressed or cast body 200 containing a rectangular central window 201. In view of the relatively short-duration of a pour (from ; 25. the time of filling to the time of completely discharging the vessel) this body is heated to only a relatively low temperature, e.g. between 400 and 500C (when casting st~el which heats up the walls of the discharge passage to more than 1500C).
For this reason it ls not absolutely necessary to make the body 30. 200 of a refractory material. More important is the choice of K~NK/JP

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a material that is dimensionally particularly stable and - insensitive -to tempera-ture shock of the described kind, : so that this body 200 can serve as a durable frame for the ; actual gating portion of the sliding plate 112.
5. The window 201 contains a member 202 which is of the same . thickness as the body 200, but which has a slight clearance in the window 201 to facilitate replacement.
The member 202 has chamfered edges 203 and a cast--in cylindrical sleeve 205 which defines the discharge passage 105 : 10. for the metal through the sliding plate. This sleeve may be produced by pressing and firing or by casting a h.ighly refractory mass. Without significantly increasing the cost of a sliding plate the sleeve may consist of a material of the highest quality, : such as zircon, which can be standardised for size and shape 15. and which will consitute only a small part of the entire vo].ume of -the plate.
The member 202 consists of refractory concrete of a quality that should be chosen to allow for the aggressiveness of the . molten metal in question. In the majority of cases a concrete : 20. as specified above in Example 3 will satisfy the needs of the ~ case. If the member 205, as is preferred, is used, then the .~ member 202 may be made of a lower quali-ty, such as -that described in Examples 1 and 2 above.
The member 202 contains the gas-permeable ~nsert 15~ embedded 25. therein supported by a metal plate 182 which has an opening 1~
., .
~communicating with an opening 189 at one end of a metal tube ]80 ~; of ~hich the other end opens into a distributing~ chamher -08 at the bottom of the gas-permeab].e insert 156.
The gas perrneable insert 156, the tube 180, an~ the metal 30. plate 182 are assembled and cemented or otherwise joined toge;ther, KDNK/JP
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as indicated at 209, before the refractory concrete is poured.
Figures 16~ 17 and 18 i.llustra-te ~ ~-plate sliding gate nozzle apparatus in which the ~ ..Lng plate 112 corresponds t~
C the sliding plate in Figures ~ and 15. The fixed plates 5. are marked 110 and 111.
The lower fi.xed plate 111 is mounted in a supporting frame 1~1 in a prepared bed of mortar 131~. The metal dis-charge passage through the 3-plate sliding ~ate nozzle apparatus is generally identified by 106,.~ut the sleeve.for lining the 10. discharge passage has been omitted.
. In its upper surface the lower fixed plate 111 contains a recess 154 which communicates with a supply duc'c 155 and with a connecting gas pipe 157 for supplying the gas-permeablc insert 156 with gas. When the gate is wide open, as in Fi~ure 16 15. no gas can enter.
However, when the gate is partly closed, as in Figure 17, :: the gas entry opening is partly uncovered and some gas a ready passes into the discharge passage 106.
Finally, when the gate is .fully closed as in Figure 18, thf.
:~ 20. gas supply is completely unco~ered and the gas flo~rs at maximum ~: rate into the dlscharge channel 106.
The recess 154 is so located in the lower fixed plate 111 . and it is of a length such that durin~ the closing movement of the sliding plate 112 the supply of gas -to the gas-permeabl.e .:..... 25. insert 156 through the gas pipe 157, the gas duct 155, the recess 15~ and the tube 180 will begin when the gas-permeabl.e : insert 156 enters the discharge passage 106, and that a full ra-te gas supply to the gas-permeable insert 156 will. be assured when the sli.ding pla-te 112 is in closing position.
: 30. Fi~ure 19 is an embodiment of a 2-plate slidi.ng gate .~ KDNK/JP

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nozzle apparatus in whlch 165 indicates a slîding plate co-operating with a fixed plate 169 which in its underface contains a recess 177 supplied with gas through a duct ~8 and a gas supply pipe 183a.
5. The 2-plate sliding gate defines a metal discharge passage 106. The sliding plate 165 contains a gas-permeable insert 156 which receives the gas through a duct 179 and a distributing chamber 178. The distributing chamber 178 is ~ covered by a metal plate 178a. The gas is supplied in the `, ~ 10. same way as described in the case of the 3-plate sliding gate .. .. .
~; j in Figures 16, 17 and 18.
The fixed plate 169 is contained in a holder 174 and bedded in mortar 176.
Figures 20 to 22 illustrate the ninth embodiment of the 15. invention in its application to a nozzle brick or sleeve.
¦ Figure 20 shows a nozzle brick 212 held in position ,' in a mortar layer 213 in the bottom brick 54 o~ a vessel ,~ adapted to hold molten metal.
..
Alternatively, the mortar layer 213 could be replaced 20. by a jacket of fire-resistant felt or ceramic fibre material.
For the purposes of the invention it is of particular advantage ~, to secure this jacket to the coned outer surface of the nozzle brick or sleeve 212 whilst the concrete is being poured. The advantage thus achieved is of a dual nature. Though providing 25. a good seal the jacket will not adhere to the internal wall of ; the bottom brick 54. ~Ience the more rapidly wearing sleeve 212 can be easily removed without damage being done to the bottom brick 54, whereas on the other hand the preformed bond between the jacket and the sleeve ensures bo-th correct positioning of 30. the sleeve and an easy removal of the jacket when the sleeve 212 is removed.
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It is of the essence that the sleeve 212 should consist of a refractory concrete because the operationally safe application of such a jacket which forms a layer of consistent thickness on the peripheral surface of the sleeve 5. 212 demands the observance of close tolerances in overall dimensions and angles during the fabrication of the sleeve.
-' This is assured when using a refractory concrete. In -the case of a burnt material experience shows that such close tolerances cannot be assured without resorting to expensive 10. 'subsequent machining.
The re:~ractory ceramic fibre and felt material is ; ' pre~erahly 3 to 4 mm thick, its bulk weight is 170 to 210 ,' kg/cub.m, e.g. 1~2 kg/cub.m, and the fibre gauge is roughly :
3 to 4 microns. The material is preferably compressible to 15. hal~ i~s thickness. If the sliding gate nozzle is to be used in the casting of a metal melt at temperatures up to about 1260C a suitable felt would contain about 52% by weight '' of SiO2 and 48Y3 by weight of A1203- ~or higher temperatures ; ,, up to about 1500C it is advisable to make use of a felt baséd , 20. on a chromium aluminium silicate ha~ing a co,ntent of for example .: ., .
54.5% by weight of SiO2, 42.3C~o by weight of A120~ and 3.2%
by weight of Cr~0~ and a melting point above 1650C.
The sleeve 212 contains a gas-permeable insert 215 ' preferably surrounded by a metal cylinder 216 which leaves a Z5. clearance creating a gas distributing chamber 217. The end of the cylinder 2'6 is sufficiently far away from the metal discharge passage 55 to be protected by the insulating effect of the refractory concrete. A gas duct 218 is provided and may be defined by a cast-in leng~th of tube (not shown) or it 30. may be bored into the brick. The gas may then be supplied to the porous insert through a tube 219 located 'between,the ~DNK/JP

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ladle bottom arld its brick linin-g and emerging through the bottom 52 on the outside of the frame 5~ of the plate. If preferred the tube 219 might also be located between the bottom 52 and the frame 58 above the fixed plate 67.
5. The sleeve 212 in Figure 21 may be produced in a mould 222 by pouring with the provision of cores 220 and 221. The core 220 is introduced through the bottom of the inve~ted mould ` form 222 and the metal sleeve 216 together with the insert 215 is placed on the metal disc 216a, which is held by the conical 10. part 223 of the core. If a jacket of refractory felt is to be interposed between the .sleeve 212 and the nozzle brick to form a seal, then a preformed coned felt Jacke-t 213a is located inside the form. The core 221 is then positioned on the end of the core ~20. The refractory concrete is poured into the form 15. and the mouldLng taken out when set to be stored until fully hardened. Finally the duct 218 is produce~ by drilling (see ; ~igure 20).
Figure 22 relates to particulars of a preferred geo-metrical configuration of the gas-permeable insert 215. This 20. has a generally square cross section and chamfered edges to enable it to fit into the cylindrical sleeve 216. The four cavities thus created represent a dis-tributing chamber 217.
Communication between the several cavities is provided by `~ peripheral grooves 224 and 225.
25. ~
Gas-permeable or porous inserts for slidin~ gate nozzle appara-tus fitted to casting ladles can be produced as follows:
Raw material: - High purity corundum of a particle size between O.5 and 3 n~ and between 1 and 3 mm.
30. Bondi.ilg agent:-KD~K/JP

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a) Clay cont,aining not less than 43C~o A1203: up to , percent byweight (particle size 0 to 0.25 mm).
b) Aluminium monophosphate : up to 1.5 percent by weight (5~%
' aqueous solutilon).
5. Bricks are compacted from this mix under a pressure of 500 to 600 kp/sq.cm. and the compacted masses are then kilned for not less than four hours at l600C.
The physical properties of the bricks are:-Permeability to gas:- 500 -to 700 nanoperm lO. Cold compressive strength:- 250 to 350 kp/s~.cm.
A few general explanations will be of assistance:- the proporti.on of open pores in volume percent is determined by the method of "Washburn". In this context it should be " emphasised that the permeable pore volume may be only a ; 15. proportion of total porosity.
The gas permeability (according to DIN 51 058) is measured in nanoperm. l nanoperm corresponds to lO 9 perr~s.
A gas permeability of l perm is defined as the gas flow of l cc/sq.cm/sec. driven by a pressure differential of one 20. dyne/sq.cm through a permeable body l cm thick, when the viscosity of the gas is l poise.
We re~er now to Figure 23. This shows a moveable sliding plate 63 of a two-plate slidingr gate nozzle for a vessel adapted to contain a metal melt. Such sliding gates are known 25. in the art and the fixed plate of the gate is not therefore shown.
, t The sliding plate 63 contains an orifice 55 for the ; passage therethrough of the metal melt. It is sup~orted by a metal frarne 64.
The side of the sliding plate 63 facing away from its ' ' , ~DNK/JP

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~, sliding face is provided with a metal reinforcement 229 .'. in the form of a ~lat meta]. sheet or a ~lat meta]. platç.
,. The reinforcernent 229 e~tends across the entire underlace ' ~ !
'.' of the slidinglplate 63 and it is connected to the p],ate so5. that neither tension, cornpression or shear forces can mo~e it.
For transmitting the thrusts, which arise when -the gate : i~ operated, from -the supporting frame 64 to the sliding plate ': 63,the supporting frame 64 is formed with elevations 232 . and 233 which co-operate with correspondingly shaped shoulders . 10. 230 and 231 formed by the rei.nforcement 229. The elevation.s ,. 232 and 233 on the supporting frame 64 may be ri~s extendin.g across the direction o movement of the sliding plate 63, the length of the ri'bs substantially equalling the width of the ,, sliding plate 63.
15. It will. be understood that the length and width of these ribs or elevations 232, 233 are arranged to comply with the demands that arise in any particular sliding gate nozz]e. In Figure 23 the elevations 232 and 233 on the supporting frame 64 are disposed a relatively short distance away from the 20. orifice 55 for the passage of the metal, so that only com-paratively slight flexing of the sliding plate 63 can occur in use.
If it is desired that the sliding pla-te 63 should be capable of more pronounced bending the elevations 232 and 25. 233 on the su,pporting frame 64 and the cooperating shoulders 230 and 231 of the sliding plate 63 may be spaced further apart and more particularly the elevation 232 and the shoul,der 230 may be loca-ted nearer the end of the sliding plate 63 as . .is illustrated in Figure 24.
~'' 30. It will be understood that the elevations 232 and 2.33 ," KD~/JP ,, , :~ ~4 ~ ` .
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on the supporting frame 64 and the shoulders 230 and 231 - of the reinforcement 229 will be in direct engagement when the sliding galte is operated.
In the embodiment shown in Figures 25 and 26 the 5. reinforcement again comprises a flat metal sheet or a flat metal plate 235. The reinforcement extends over the greater part of the underside of the sliding plate 112 and contains an opening 236 of a diameter exceeding the diarneter of the orifice ]06 for the molten metal. Preferably the diameter 10. of the opening in the reinforcement 236 may exceed the diarneter of the orifice 106 by an amount ranging between ]20 and 300/0, preferably from 140 to 200%. Consequently when the refractory concrete is being poured during the production of the sliding plate the gap between the orifice 106 and the 15. opening 136 in the reinforcement will fill up with refractory concrete and the reinforcement 235 will thus be sufficiently insulated from the teeming metal whilst casting proceeds.
The reinforcement 235 is provided with six tabs 237 ; which are integrally formed on the edges of the reinforcernent ; 20. and bent upwards to embrace the sides and ends of the sliding plate from the outside.
: .
Figures 27, 28 and 29 show three modified embodiments of this type of reinforcement which in each case contains an opening 236 having a diameter exceeding that of the orifice 25. 106 as has above been described.
In the embodiment shown in Figure 27 the reinforcement comprises parts 238 and 239 which have heen bent out of the general plane defined by the reinforcementO In a manner - similar to the tabs 237 in Figures 25 and 26 these bent parts 30. create a firm anchorage for taking up tension, compression and ':
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shear stress that may arise between the reinforcement and the body of the sliding plate 112~ the anchorage or~mechanical . . I
interlocking being created whe~ the plate is being produced from refractory concrete by casting.
- 5. In the embodiment shown in Figure 28, the reinforcement ; contains indentations or depressions 240 which in a similar way also establish a secure anchorage between the reinforcement and the body of the sliding plate. In a modific~tion of this embodiment the depression 240 are replaced by punched up 10. perforated loops so that concrete can penetrate the loops and form a flush bottom face thereby increasing the interloc~ing between the refractory concrete and the metal]ic reinforceme~t.
In the embodiment shown in Figure 29 the only difference is that the reinforcement i8 perforate~
15. In all these examples the upper sliding face of the slidin~ plate is manufactured so that i-t is ~arallel to the underface of the reinforcement.
Figure 30 shows a three-plate sliding gate nozzle in which the sliding plate 112 has the form shown in ~igures 25 20. and 26. The fi~ed plates 110 and 111 of the sl!~ding gate nozzle are provided with sheet metal reinforcement resernbling the sheet metal reinforcement 235, the upper fixed pla-te 110 being provided with the reinforcement on its upper surface and the :, .
lower fixed plate 111 on its underface.
25. The sheet metal reinforcements are each formed with tabs 237, as in Figures 25 and 26, and these tabs 237 embrace the sides and ends of the sliding plates ~ , 111 and 112 from the outside whilst being embedded therein.
. . .
- A supporting frame 118 is associated with the upper fixecl 30. plate 110 and a supporting frame 131 with -the lower fix~ed plate : 3~

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111. Both frames 118 and 131 are provided with a plurality " . .
of projections or bearing abutments 245 on their side facing the plate 110 ~r 111, and the sheet metal reinforcements 235 bear against these abutments. Th~s ensures that the 5. fixed plates 110 and 111 will be automatically fitted firmly and correctly without the need to use mortar.
Should it be desirable, sliding plates which are reinforced in accordance with the invention may be reduced in thickness to less than the thickness attainable by - 10. conventional pressed and fired sliding plates. ~or instance, .,:
; the ratio of length to thickness may exceed 15:1, e.g. 20:1 to 25:1 or even more.
Figures 31 to 33 show a cast sliding plate 63 containing lengthwise and crosswide reinforcing ele~ents formed on its 15. underslde by T-sections 250 and 251 extending along both sides of the plate and interconnected by three welded transverse ,; . .
plates 252, 253 and 254.
.~ Figure 34 shows in plan view a sliding plate 312 which contains a metal reinforcement like the above descri~ed :~.
20. sliding plates although this cannot be seen in the illustrated view from above. Only an opening 314 can be seen ~hich is -~; reinforced wi-th sheet metal in a manner that will be later ... .
described with reference to Figures 35 to 39.
Bearing elements 315 indicated in discontinuous lines and 25. conveniè~tly f`ormed by suitable elevations or abutments are pro~
vided on that side of the supporting frame ~ot here showrl) which ,.:,, ~;~ faces the sliding plate. The reinforcement of the sliding plate ., .
~ 312 rests on these bearing elemen-ts. Consequently the reinforced ~, .
sliding plate 312 is freely suspended i.n the region of the .;
30. discharge passage 106. The plate is ; KDNK/JP
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thus capable of slight deformation when subjected to the effects of forces that arise in use.
The production of a slidin~ plate according to this aspect o~ the inven-tion wilJ. now be more particularly 5. described ~lith reference to Figures 35 to 39.
Figure 35 shows a mould 401 in which the prepared rein-forcement 402 shown in Figure 37 is first placed in position. In the illustrated case the reinfor~ement 402 consists o~ a ~etal æheet (or plate) 403 containing a t~bular sheet metal insertion 10. 4Q4 covered by a cap 405. Projections, for instance in the form o~ metal pins or bosses, 406, are welded to the sheet metal reln-forcement 403. These pinS ~0~ serve to create a mechani.cal int~r-lock and thus secure anchorage between the reinforcement 402 ~nd the re~ractory concrete constituting the sliding plate. In a 15. further preferred modification we provide the pins 406 with bro~d-; ened heads or tangs or recesses so as to increase the in~erlocking o~ the metal reinforcement to the re~ractory concrete.
e bottorn of the mould 401 contain~ holes 407 through which ejectors 40~ can be introduced to eject the finished 20. sliding plate .~rom the mould 401. This action is illustrated - diagrammatically ln Figure 36.
At the instant illustrated in Figure 35 the mould 401 , ,: .
has been prepared for the produc-tion of the slid ng plate by pouring refractory concrete and compacting the same, e.g. by 25. vibration. The mould 401 is thus filled with refractory concrete, the surplus concrete being skimmed off over ~he ed~e which is machined parallel to the bottom of the mould 401.
It may be noted that the ca~ 405 May consist of any suitable material since its purpose is to prevent the 30. refractory concrete from entering the tubular reinforcement insertion 404~ However, i~ ~ormed as a welded on steel cap, KDNK/JP
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it co~ld also increase the mechanical interlocking.
Figure 36 as~above mentioned, diagrammaticall~ shows the .. , i .
plate being pus~ed out of the mould as soon as the concrete has initially set. me reinforcement sheet 402 serves as 5. support and prevents the sliding plate from warping in storage and during further treatment (curing, drying and ; so forth). At the same time the mould 401 is thus again quickly available for fllrther use.
Figure 38 diagramrnatically shows a side elevation of , . . .
10. part o~ a supporting frame 411 o~ conventional kind. According to the invention this supporting frame 411 is subsequently ;; provided with a firmly fitted boss or stub 409 which is of ".;
a diameter so calculated that it will be a sliding fit in the tubular insertion 404, in the reinforcement 402. A flat disc 1~. 412 embraces the boss 409.
; Figure 39 shows the reinforced sliding plate 413 about to be assembled with the supporting frame 411. The reinforcing metal sheet 402 rests on the disc 412 which absorbs the vertical forces 9 transmitting the same through the supporting - 20. frame 411 to ways not shown in the drawing. The boss 409 ; inside the insertion 404 provides anchorage for the slidlng,,~ plate against horizontal displacemen-t inthe supporting frame 411 without, however, preventing horizontal thermal expansion.
The^boss 409 also takes up the entire thrvst when the sliding ,,.,. ~ , .
~,` 25. plate is operated. The transmission of this thrust by the ~` boss 409 through the reinforcement 402 to the concrete component of the plate 413 is effected by elevations, projections or stubs 406 and the tube 404.
e disc-shaped bearing member 412 on the illustrated .
30. long side of the sliding plate corresponds to at least cne ; KDNK/JP
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, $9 corresponding abutmen-c on the short side no-t sho~ in the drawing, resembling the abutments 245 in Figure 30 and 315 in Figure 34.
In the above-described embodiment the resultant bending 5. stresses are taken tlp by the reinforcement. In the same way as in the embodiment according to ~igure 34 this affords the ad~antage that the sliding plate by bending will be relieved of undue compressive stress due to thermal expansion when locally heated in the neighbourhood of the discharge 10- passage forthe molten metal. Furthermore, the provi.sion of these bearing abutments makes the reinforcement amenable to precise static calculation.
It must still be mentioned that the boss 409S if desired~
may be provided with a central bore for the admi.ssion there-15. t.hrough of a gas.
Examples of refractory concretes which can be used forthe above sliding gate nozzles are described above in Examples ; .
1, 2 and ~.
In a modification of the arrangements of Figures 35 to 39 a hole is drilled in the suppor-ting frame 411 of a si7e to accommodate the tube 404 lfihich is extended downwardly through the reinforcing element 402 so as to engage the hole in the frame 411. This tube can then be used as a working fiuid inlet and w.~thin the plate can communica-te with a duct for working fluid.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A refractory structure comprising a body of refractory concrete material defining at least one discharge passage for molten metal passing through the body and at least one reinforcing element located within the body or forming a face or faces thereof and interlocked mechanically with the refractory concrete with which it is in intimate contact over the whole of any of the surface of the reinforcing element which is juxtaposed to the refractory concrete, the reinforcing element being separated by refractory concrete material from any surface of the refractory structure which con-tacts the molten metal in use.

2. The refractory structure as claimed in claim 1 including means defining at least one duct for a working fluid in the body.

3. The refractory structure as claimed in claim l or claim 2 in which the discharge passage is defined by an insert material embedded in the refractory concrete having better wear resistance than the refractory con-crete.

4. A refractory structure as claimed in claim 2 wherein the duct for a working fluid comprises a tortuous duct located in the structure and extend-ing from an inlet in a face or side of the structure to an outlet in the same or another surface of the structure.

5. The refractory structure as claimed in claim 4 in which the tortuous duct extends around at least 180° of the circumference of the discharge passage.

6. The refractory structure as claimed in claim 4 in which the means defining a duct for working fluid comprise gas permeable porous material opening out through a surface of the structure which will be in contact with molten metal during at least some of the time when the refractory structure is in use.

7. The refractory structure as claimed in claim 6 in which the gas permeable porous material is an insert directly embedded in the refractory concrete body and said duct includes ducting connecting the porous insert to an inlet to the ducting, spaced from the porous insert, and located in a side or a face of the structure.

8. The refractory structure as claimed in claim 7 in the form of a sliding plate for a sliding gate nozzle apparatus, the inlet to the ducting for the working fluid being located in a surface of the plate at a location which is remote from the part of the plate which will contact molten metal in use.

9. The refractory structure as claimed in claim 8 in which the inlet is located in one of the major faces of the plate and is so positioned as to communicate with the outlet to said ducting, adapted to supply working fluid, formed in a fixed plate with which the sliding plate cooperates when the sliding plate is in a position in which it is wished to introduce working fluid into the duct in the sliding plate.

10. The refractory structure as claimed in claim 6 in the form of a sliding plate for a sliding gate nozzle apparatus comprising a gas permeable insert, ducting and a metal plate, the gas permeable insert and ducting for the working fluid being located on said metal plate which is embedded in a face of the plate at a position remote from the part of the plate which will contact molten metal in use.

11. The refractory structure as claimed in claim 10 including a fixed plate, wherein in the sliding plate the ducting for the working fluid passes round at least 180 of the circumference of the discharge passing before reaching the porous insert and the ducting has an additional outlet located in one of the principal faces of the plate at a position, remote from the part of the plate which will contact molten metal in use, and such that the said outlet is adapted to cooperate with a duct or recess formed in the fixed plate with which the sliding plate is adapted to cooperate in use, the duct in the fixed plate having an outlet in the face which contacts the sliding plate, the positioning of the inlets and outlets of the duct in the fixed plate and the additional outlet in the sliding plate being such that gas cannot pass therethrough when the sliding plate is in the closed position.

12. The refractory structure as claimed in claim 2 in the form of a nozzle brick for the outlet opening of a metallurgical vessel.

13. The refractory structure as claimed in claim 12 in which the means defining a duct for working fluid comprise a gas permeable porous sleeve forming at least part of the wall of the discharge passage and the duct has an inlet in a face of the structure at a location remote from the part of the nozzle brick which will contact molten metal in use.

14. The refractory structure as claimed in claim 13 in which the duct for the working fluid communicates with at least substantially the whole of the face of the porous insert remote from the face which will contact the molten metal in use.

15. The refractory structure as claimed in claim 12 having a refractory felt partially embedded in its outer surface.

16. The refractory structure as claimed in claim 1 in which the rein-forcing element includes keying members which key the reinforcing element to the refractory structure.

17. The refractory structure as claimed in claim 16 in which the reinforcing element is located at a face which, when the structure is in use, will be remote from the face of the structure which will contact molten metal or at least 20% of the thickness of the structure away from such a face.

18. The refractory structure as claimed in claim 16 in which the keying members comprise tabs, tangs, loops, pins, bosses or bars extending into the refractory concrete or perforations, channels or ducts in the reinforcing element into which the refractory concrete extends.

19. The refractory structure as claimed in claim 1 or 2 comprising means defining at least one duct for a working fluid, the structure comprising at least two separate parts secured to each other at least in use, the duct being defined between the said parts.

20. A process for making a refractory structure which comprises pro-viding a mold defining the external shape required for the component, locating in the mold at least one reinforcing element so shaped as to be able to mechanically interlock with the refractory concrete and means defining a discharge passage, pouring a cold curing, cold setting refrac-tory concrete composition into the mold around the reinforcing element in such a way that the concrete mechanically interlocks with the reinforcing element when it has set, and the discharge passage defining means, com-pacting the concrete, levelling the concrete in the mold, allowing it to set and removing it from the mold before or after allowing it to cure, and drying the concrete.

21. The process as claimed in claim 20 including locating means adapted to define a duct for a working fluid in the mold before the concrete composition is placed in the mold.

22. The process as claimed in claim 21 in which the means adapted to define the duct comprise material meltable at a temperature which does not damage the refractory concrete and includes heating the concrete structure after it has been cured to a temperature sufficient to melt the material and pouring or blowing it out of the structure.

23. The process as claimed in claim 21 or claim 22 in which the means adapted to define the duct comprises porous gas permeable material.

24. A sliding gate nozzle apparatus adapted for use with metallurgical vessels comprising at least one fixed and one movable plate and a supporting frame associated with at least one of the plates, and each plate having a discharge passage for the passage therethrough of molten metal, at least the sliding plate comprising a refractory structure as claimed in claim 1.

25. The sliding gate nozzle apparatus as claimed in claim 24 in which the sliding plate or the fixed plate or both comprise a refractory structure as claimed in claim 7, the reinforcing element being provided on the side of the plate facing away from its sliding face, the sliding plate or the fixed plate or both being located in the supporting frame with which it is associated without the use of mortar, the supporting frame and the reinforcing element including cooperating elements for transmitting thrust therebetween when the gate is operated.

26. The sliding gate nozzle apparatus as claimed in claim 24 in which the sliding plate or the fixed plate or both comprise a refractory structure as claimed in claim 7, the reinforcing element being provided on the side of the plate facing away from its sliding face, the sliding plate or the fixed plate or both being located in the supporting frame with which it is associated without the use of mortar, the supporting frame and the reinforc-ing element including cooperating elements for transmitting thrust there-between when the gate is operated and in which the elements for transmitting the thrusts which arise when the gate is operated comprise abutments on either side of the discharge passage in the supporting frame, said abutments cooperating with shoulders on the plate formed by the reinforcing element.

27. The sliding gate nozzle apparatus as claimed in claim 24 in which the sliding plate or the fixed plate or both comprise a refractory structure as claimed in claim 7, the reinforcing element being provided on the side of the plate facing away from its sliding face, the sliding plate or the fixed plate or both being located in the supporting frame with which it is associated without the use of mortar, the supporting frame and the reinforc-ing element including cooperating elements for transmitting thrust there-between when the gate is operated and in which the elements for transmitting the thrusts which arise when the gate is operated comprise abutments on either side of the discharge passage in the supporting frame, said abutments cooperating with shoulders on the plate formed by the reinforcing element and in which the abutments on the supporting frame extend across the direction of movement of the sliding plate and consist of ribs extending a distance corresponding to the width of the plate, each cooperating with a complementary shoulder formed by the reinforcing element.

28. The sliding gate nozzle apparatus as claimed in claim 24 in which the sliding plate or the fixed plate or both comprise a refractory structure as claimed in claim 7, the reinforcing element being provided on the side of the plate facing away from its sliding face, the sliding plate or the fixed plate or both being located in the supporting frame with which it is associa-ted without the use of mortar, the supporting frame and the reinforcing element including cooperating elements for transmitting thrust therebetween when the gate is operated and in which the elements on the supporting frame which are adapted to transmit the thrusts which arise when the gate is operated comprise a pin provided at least at one point spaced away from the discharge passage, the said pin engaging a reinforcement socket in the plate.

29. The sliding gate nozzle apparatus as claimed in claim 24 in which the sliding plate or the fixed plate or both comprise a refractory structure as claimed in claim 7, the reinforcing element being provided on the side of the plate facing away from its sliding face, the sliding plate or the fixed plate or both being located in the supporting frame with which it is associ-ated without the use of mortar, the supporting frame and the reinforcing element including cooperating elements for transmitting thrust therebetween when the gate is operated and in which the reinforcing element rests on at least three bearing abutments on the inside surface of the supporting frame.

30. The sliding gate nozzle apparatus as claimed in claim 24 in which the sliding plate or the fixed plate or both comprise a refractory structure as claimed in claim 7, the reinforcing element being provided on the side of the plate facing away from its sliding face, the sliding plate or the fixed plate or both being located in the supporting frame with which it is associated without the use of mortar, the supporting frame and the reinforc-ing element including cooperating elements for transmitting thrust there-between when the gate is operated and in which the reinforcing element rests on at least three bearing abutments on the inside surface of the supporting frame and in which at least three of the bearing abutments are disposed symmetrically at a distance about the discharge passage so that the sliding plate can freely bend slightly in the axial direction in the region surrounding the discharge passage.