Note: Descriptions are shown in the official language in which they were submitted.
l~9~
This invention relates to slabs for use in lining
containers, particularly to lining slabs formed of refractory
heat insulating material used to line molten metal containers
; in the metallurgical industry.
One particular area of application of the present
invention of considerable value is in the lining of tundishes.
Tundishes are vessels used in c~nt~ casting to provide
a constant head of molten metal to feed into a continuous
casting mould. During the process of continuous casting,
metal is fed to a tundish e.g. from one or more ladles ahd
is allowed to flow from the base of the tundish via one or
more nozzles into one or more casting moulds. Tundishes are
usually constructed of an outer metal casing lined with a
relatively permanent refractory lining, which may either be
made up of bricks or may be a ~0nithi~ lining of refractory
concrete cast in situ.
In recent years, a practice has grown up of
protecting that relatively permanent refract~y lining with an
inner lining of an expendable nature, i.e., after each casting
cycle, the inner lining is removed and discarded, a fresh inner
lining being installed prior to the commencement of the next
casting cycle. Such inner linings which are described ~n
British Patent Specification 1364665 are generally made up of
a set of slabs of refractory heat insulating materials-
German Offenlegungsschrift 2435895 describes a tundish having
; a relatively permanent lining and an expendable lining made up
of a set of slabs of refractory heat insulating material and
having a layer of loose particulate material such as silica
~and between the expendable and permanent linings.
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The layer o~ loose particulate material has a number o~
advantages: in particular, if molten metal penetrates the
joints between the slabs forming the expendable lining,
the particulate material prevents damage to the relatively
permanent lining. In addition, the layer of particulate
material, usually sand, provides a bedding layer for the slabs
of the expendable lining so that they are evenly supported
and the incidence of cracking under the effect of the
metallostatic presqure when the tundish is filled is sub-
stantially reduced or eliminated entirely. The intermediateloose particulate layer also improves the thermal insulation
around the molten metal.~
In both these cases, i.e. with or without the layer
of loose particulate material, it is customary to seal the
joints between adjacent slabs of the expendable lining using a
refractory mortar or cement. This sealing assists in
preventing molten metal penetrating the joints and coming into
contact with the relatively permanent lining and, where a loose
fill of particulate refractory material is used, prevents that
material entering the cavity of the tundish which in use is to
be filled with molten metal~
The application of refractory mortar or cement to
joints is time-consuming and requires skill on the part of the
persons lining the tundish. In addition to the actual operating
time required to set the slabs, many refractory mortars or
cements require to be dried before the tundish can be put to
use. Tundishes are expensive and constraints of this nature
are accordingly very uneconomic.
Within the metallurgical industry and in other
industries such as the construction and packaging industries
analogous situations arise in which linings are backed by
loose fill material. Analogous difficulties arise from
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penetration of the loose ~ill through the joints necessitating
the adoption of measureS such as sealing compounds, cements
or gaskets, all of which are complex, expensive and time-
consuming to apply.
According to a first feature o~ the present invention
there is provided a slab having two substantially planar
substantially parallel major faces, and two opposite regu~larly
castellated edges, the edges having a length that is large
relative to the thickness o~ the slab, said castellated edges
including a plurality of teeth with slots defined between the
teeth, said slots extending from one major face to the other,
each said tooth having a base and a top, and having a pair of
opposite sides that are not disposed in the plane of said
major faces, the top of each tooth being substantially of the
same dimension as the spacing provided by each slot between the
teeth, said teeth sides being inclined in a direction skew to
the plane of a majorfao~h~,~l~b, ~he inclination, dimensions,
and spacing of each of the castellation teeth being such that any
line normal to the plane of a major face of the slab at any
caste~ated edge portion thereof passes through the material of
the slab, and said castellated edges being so arranged that
two identical slabs may be interengaged side by side with their
respective major faces disposed in the same planes, with their
castellations interengaged and with the respective edges
extending between the castellated edges in alignment, by
moving one slab relative to the other in a plane parallel to the
plane of one of said major faces.
~ Preferably the position of the castellations on the
- castellated edges is such that two identical slabs may be
interengaged side by side with their non-castellated edges
aligned with one another. Preferably the inclination and
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dimensions of the castellations are such that when two slabs
are ln~r~n~ side by side, any line normal to the plane
of a major face of the slab passes through the material of
at least one of the slabs.
The castellations may vary widely in their
configuEati~on, and may have generally flat, curved or faceted
faces. Simple geometry is preferred for the castellations,
however, to facilitate manufacture of the slabs. Thus,
preferably the base and top of each castellation is a
10 parallelogram lying in a plane normal to the plane of a maior
face of the slab. The sides of s~ d~eb~ti~ .w~h are
preferably in par~llel planes, will generally in such a case
be rectangular.
According to a particularly preferred feature of
the present invention there is provided a container for
molten metal having a floor and sidewalls and having an inner
wall lining made up of a plurality of slabs of refractory heat
insulating material, at least some of the slabs having the
structure previously de~$ined herein, with interengaging
20 castellations farming the joints between the slabs, wherein all
joint faces of the castellations not lying in vertical planes
slope downwardly away from the interior of the molten metal
container.
In a ~ar~i~u;l~ yy preferred form, the slabs are
used to constitute an inner lining for a tundish and are
I superimposed on a layer of loose fill refractory material.
p In such circumstances, the wall lining slabs are generally
arranged incllned outwardly upwardly. The arrangement
should be one in which the thickness of the slabs, the angle
30 of the castellations, the period of the castellations and
the inclination of the slabs are so chosen relative to the
angle of repose of the loose fill refractory material, usually
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sand, between the slabs and the relatively permanent lining
that the loose fill particulate refractory material does not
penetrate the joints.
In order to ensure that no leakage of particulate
material through the joint can occur, it is preferable that
a line drawn from the lower edge of one castellation adjacent
the loose fill to the upper edge of the next castellation
of the same slab adjacent the interior of the tundish rises
at an angle of about 15 to the horizontal.
Slabs of the present invention may be made of any
convenient material. When used for lining tundishes and
other metallurgical vessels they are conveniently and
preferably made of materials of the type disclosed in the
British Patent Specification and German Offenlegungsschrift
~eferred to above.
It is found that slabs according to the present
~ invention can be assembled easily and quickly to line areas
; and that great care does not have to be exercised when
assembling the joints. An exact and tight fit is not
necessary in order to give a joint resistant to penetration
by loose particulate material.
It will be appreciated that in lining any particular
container or cavity, only some of the lining slabs need be as
defined above and indeed it will often be advantageous for
specific purposes to provide lining slabs for use in conjunction
with slabs according to the present invention which are not so
castellated, though those additional lining slabs may have one or
more edges bearing some form of castellation for interengagement
with slabs according to the present invention.
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The invention is illustrated by way of Example with
reference to the specific case of the lining o~ a tundish for
use in continuous casting, and with reference to the accompany-
ing drawings.
In the drawings,
Figure 1 is a perspective view of a slab according
to the present invention,
Figure 2 is a perspective view on an enlarged
scale of one corner of the slab of Figure 1,
Figure 3 is a perspective view of one end of a
lined tundish, and
Figure 4 is a perspective view, part broken away,
of a joint between two ining slabs.
Referring first to Figures 1 and 2, a lining slab
according to the present invention as illustrated is a substan-
tially rectangular slab having two opposite edges E castellated
and two plane edges F. The sides of the castellations S do not
run normal to the major plane of the slab but run at an angle
thereto, preferably at an angle of about 45. It will be seen
that the base B of each castellation on one side of the slab
corresponds to the protruding part of the castellation on the
other side of the slab. Thus a plurality of slabs as shown in
Figure 1 may be fitted together side by side with their uncastel-
lated edges F in line.
Referring now to Figures 3 and 4, these show part
of a tundish used in the continuous casting of molten metal.
The tundish consists of an outer metal casing 1
which is provided with a relatively permanent refractory lining
2 either made of refractory brick or of refractory concrete cast
in situ to define an inner cavity having flat walls and base.
In order to protect this relatively permanent
lining in use, the interior of the tundish is lined with
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expendable lining slabs. First a plurality of lining slabs 3
is set on the floor of the tundish. These slabs are generally
rectangular and some of them hav2 apertures which correspond to
nozzle outlets 4 in the base of the tundish. These slabs may be
abutted together or interengaged by means of castellations.
After the floor has been lined with slabs 3, the
walls are lined using slabs 5 according to the present invention.
Slabs 5 are assembled together with interengagement of the
castellations at their edges to form joints 6. Conveniently,
the tundish is lined with slabs 5 starting from the middle and
working outwards along each wall towards the ends of the tundish.
Slabs 5 are inclined outwardly and upwardly. At the ends, gener-
ally trapezoidal lining slabs 7 are inserted into position. ~he
edges of slabs 7 bear indentations corresponding to the castel-
lations on the edge o a slab 5. Slabs 5 and slabs 7 are held
in position and spaced from the relatively permanent lining 2
by means of pieces of scrap refractory lining slab or refractory
brick. In addition, slabs 5 are restrained from moving too far
away from the relatively permanent lining 2 by means of a number
of metal clips 8 which simply clip over the top edge of the
tundish as shown. After the slabs 5 and 7 and the clips 8 have
all been put into position, the gap between the relatively
permanent lining 2 and the slabs 5 and 7 is filled with a loose
fill 9 of sand, usually with the aid of an appropriate sand
filling apparatus such as one in which a fluidised stream of sand
may be released from a hand held nozzle on the end of a flexible
pipe. Because of the construction of joints 6 given by the
castellated edges of slabs 5, most clearly visible in Figure 4,
the loose fill of sand 9 does not pass through joints 6 and into
the interior of the tundish. Even if slabs 5 are not particu-
larly tightly butted together, the slope of the castellations,
their inclination, their relative spacing and the thickness of
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the slab ensure that the sand 9 does not penetrate to the
interior of the tundish.
The lower end face of each slab 5 may be flat as
the faces F in Figure 1 but it is preferably shaped e.g. rounded
so as to engage a correspondingly shaped groove or depression
running along the side of floor lining slab 3.
