Note: Descriptions are shown in the official language in which they were submitted.
~058867
The present invention relates to a device for
opening and closing the outlet bore of a vessel of the type
used for containing molten metalic material.
In the field of handling of molten metals, the
problem of discharging the molten metals from crucibles or
similar containers has necessitated the use of very expensive
materials for forming such valved outlets so that the outlets
can safely be used and withstand the extremely high temperatures
that result from the materials being handled and passed through
the outlet. In general, the outlets have been subject to leakages
due to rapid expansion upon exposure to the molten liquids
and then rapid contraction when the valve closure is shut or
the container emptied. It has previously been known to employ
a bottom plate which surrounds the outlet channel of the vessel
or crucible and a slmilarly shaped valve plate which is movable
relative to the bottom plate so that these plates can be inter-
changeable thus reducing the costs of replacing one or the other
plates when such plates become worn or cracked due to use over
a period of time.
Such interchangeable plates are provided with aper-
tures through which the molten metal passes when the aper-
tures are aligned by moving one plate, the valve plate, rel-
ative to the bottom plate of the vessel. It has been the
practice to provide on such a plate a key of some form, for
example, a projection which would cooperate with a groove
on another part of the assembly such as the perforated stone
C, ~ S-
lOS8867
casinq or the discharge casing. It has been the accepted
practice to provide the projection or key so that it ex-
tends in the direction of flow of the molten liquid metal~
However, with interchangeable plates, where the key is pro-
vided on the casing, then the key must run in a groove formedon the valve plate so that, at least with the valve plate,
the key portion will extend counter to the direction of
flow which is undesirable. Of course, whenever on the oth-
er hand, the key has been provided on the plates, then the
key will extend in the wrong direction, that is, counter to
the direction of liquid flow, at least on the side of the
I bottom plate of the vessel which faces away rom the iden-
tically shaped valve plate.
With these previously employed embodiments, whenever
a deviation from the accepted practice as mentioned above
1~ must be employed, it has been preferred to use the arrange-`
ment where the key surface or projection has been provided
on the casing for the reason that the accepted practice
would be followed in a critical area of the sliding closure,
namely, at the groove and key connection lying above the
sealing surface of the plates. This is important since
the highest liquid pressure occurring in the sliding valve
closure exists at the sealing surfaces for every position
of the valve. In addition to the departure from the ac-
cepted practice with regard to the groove and key connection
;
~'
. ~ Z
1058867
lying below the sealing plane, this embodiment has twoother severe disadvantages. Firstly, the plate or plates
are considerably weakened as a result of the indentation
which provides the groove at a critical point of the plate,
namely, immediately around the aperture defining a portion
of the flow passage, and, secondly, the expansion or butt
joints of the groove and key connections on both sides of
the sealing surface will be disposed where the 10w turbu-
lence is always the greatest in a circumstance where the
valve plate is not completely open.
In another known embodiment, where the key surface
is provided on the surface of the plate, there will be,
of course, no weakening of the structural integrity of the
plate and, in addition, the joints of the groove and key
connection are also located away from the area of greatest
flow turbulence. However, a serious drawback still exists
due to the fact that the greatest thickness which consists
of the thickness of the plate plus the height of the key
which projects from the plate and the area where the greatest
temperature elevation is experienced on the plate coincide~
It is well known, of course, that the absolute measure of
the degree of expansion results from a consideration of the
dimension of the element and the temperature of the element
at the place being observed. Assuming the usual case where
a sufficient pretension or strengthening as by hardening
,s~,
, ' ~i 3
lOS8867
of the sealing surfaces is provided, the expansion of
the thickness of the plates can occur only in a direction
which extends away from the sealing surfaces. Extensive
experiments have been conducted and the results reported
S concerning the fact that such expansions, due to the fact
that they cannot be freely absorbed in the system of these
elements, result in considerable pressure loads on the
edges defined by the passage and by the sealing surfacesO
As a result, where relative movement of the plates takes
place, cracking or breaking of the plates occurs. More-
over, there is the danger that the plate will be broken
at the point the key projection is connected to the plate
due to internal stresses that exist.
Of course, when the pretensioning forces of the
sealing surfaces is less than the force created by the
heat expansion in the area of the flow passage, the plates
will be able to easily expand in the direction extending
toward the sealing surfaces but, in so doing, a critical-
; ly undesirable formation of a gap between the sealing sur-
faces of the bottom plate and valve plate will result in
the areas of the plate remote from the sealing surfaces.
The portions of the plates that are thus exposed as a re-
sult of the formations of the gap can easily break away
resulting in a dangerous outflow of the liquid metal through
any gaps that develop.
.~'
~f
105886~
It is an object of the present invention to avoid
the foregoing difficulties.
Therefore, in a device for opening and closing the
outlet bore of a vessel of the type used for containing molten
metallic material the device including a protective casing having
a through bore, a first plate member having an aperture there-
through aligned with the through bore, valve means including a
second plate member having an aperture therethrough, the valve
means being mounted fox sliding movement relative to the first
plate member for controlling flow of the molten material from
the bore and first plate aperture through the second plate
aperture, and an outlet casing having a through bore aligned with
the aperture of the second plate member, the casings each having
butt joint portions disposed adjacent the respective plate members
and surrounding said bores, the improvement brought by the present
invention comprises each of the plate members having sealing
surfaces and surfaces opposite the sealing surfaces, the opposite
surfaces having means defining a groove and key connection for
the casings; the means on each of the opposite surfaces including
a bead projecting from the respective opposite surface, each
bead having inner and outer flank surfaces with the bead surrounding
the respective apertures in the plates. The inner and outer flank
surfaces are inclined toward one another, and the inner flank
surfaces of each bead has a base disposed on a diameter which
is substantially greater than the diameter of the respective
apertures to form about each apertures an annulus having a
substantial radial dimension, the thickness of each the annulus
being less than the combined thickness of the respective plate
and its bead. The butt joint portion of the outlet casing forms
with its through bore a recess having a cross-section and sloping
surface complementary to the outer end and outer flank surface of
','~
- 1058867
the second plate member bead whereby the butt joint portion of
the outlet casing is disposed adjacent the second plate member
exteriorly of its bead. The through bore of the outlet casing
narrows in the direction of flow and has its upstream end corres-
ponding in cross-section substantially to the cross-section of the
rim of the recess formed in the second plate member by the inner
flank surface of its bead.
With the structure of the present invention, it will
be possible to dimension the thickness of the plate immediately
adjacent the passage independently of the dimensioning practices
relating to the formation of a groove and key connection so
that, as a result, the usual condition, on the one hand, relating
to the expansion of the elements and, on the other hand, relating
to the distance of the butt joints from the sealing surfaces of
the plate will be optimally satisfied. Moreover, the two-
/'/
~ a -
B
~058867
flan~s of the bead forming the key are situated and
æhaped so that it will be possible to use the plate
either as a part forming a groove or a key so that
the plate can perform both of these functio~s simul-
; 5 taneously.
Further, by the use of the present invention,
it will be possible, perhaps without deviating from
the accepted practice relating to the orientation of
the groove with reference to the direction of flow
of the liquid metal, to operate with plates of the
same shape and dimensions so that the plates can be
interchangeably employed. Also, advantageously, the
bead will be disposed in an area of lesser temperature
differences as a result of its being disposed at a dis-
lS tance from the flow passage thus minimizing or entirelyeliminating the danger of cracks due to tension. It
will also be noted that the disposition of the bead away
from the flow passage will still impart a desired rein-
forcement to the plates to prevent or at least minimize
bending in the area where the ~ate is supported to a les-
ser degree by the surrounding housing structure.
The foregoing and other advantages will become ap-
parent as further consideration is given to the following
detailed description together with the accompanying draw-
ings.
:a~ ~
~05886'7
BRIEF DESCRIPTION OF THE DRAWINGS
,
FIGURE 1 is a sectional view perpendicular to theflow passage of the elements of the present invention
showing a groove and key connection of a two plate closure;
' and,
1 5 FIGURE 2 is a view similar to that of Figure 1 but
showing a groove and key connection of a three plate slid-
ing valve.
. :
,:~
,~
i
.
i
~ .
.
1058867
DETAILED DESCRIPTION OF THE INVENTION
R~ferring to the drawing, wherein like numerals
designate corresponding parts, in Figure 1 there is showm
a fixed bottom plate 10, a perforated stone casing 11
which is situated in the bottom o~ a vessel partially
shown in dotted lines at 11', a longitudinally movable
valve plate 12 and an outlet casing 13. The apparatus
for moving plate 12 is conventional and is thus not
shown. Both plates 10 and 12 have a bead 17, 17' dis-
posed concentrically in relation to the apertures 16
and 16' formed therein, respectively, with the beads
17 and 17' being formed on the sides 15 and 15', respec-
tively, which ace away from the abutting sealing surfaces
14 and 14'. The cross sections of the beads 17 and 17'
which are in the form of projections extending away from
the uniform thickness indicated 18 and 18', are in the
form of identical trapezoidal cross sections each with
two flanks, the inner one 19 and the outer one 20. The
flanks are inclined at an angle of about 10 to 15 in
- the form of concentric, annular surfaces. The inner
flank 19 has its base disposed at a diameter which is
larger than the diameter of the apertures 16 and 16l.
Both the bottom plate 10 and the valve plate 12 thus form
a groove and key connection in the area o the flow pas-
sages 16 and 16' either in relation to the stone casing
11 or the outlet casing 13, respectively. In particular,
1058867
the flank 19 of the beads 17 and 17' define the groove
forming portion. The edges of the adjacent parts of
the vessel and support structure are indicated in dot-
ted lines at 23, 23' and 21 and 21' which are not il-
lustrated in more detail as these are standard elementswhich together with the casing surface of the stone
casing 11 and the adjacent surfaces of the bottom plate
10 and the jacket surface of the outlet casing 13 re-
spectively, form a joint. Also, the'outside diameter
of the bead defined by the flank 20 functions as a key
~orming portion of the connection relative to the parts
or surfaces lying directly adjacent to it.
As a matter of practice, the groove and key con-
; nection are sealed by means of mortar placed in the gap
that exists between them. ~he butt joints 22 and 22',
in the past, have been particularly susceptible to the
danger of being washed out, particularly, whenever the
joints lie near the"sealing surfaces 14 and 14' where,
as previously noted, the greatest turbulences occur.
The possibility of having the mortar washed out between
the butt joints 20 and 22 is minimized by having a flush
surface'contact or gapless joint provided between these
parts of the plates and the casings.
According to the present invention, by way of
example, the beads 17 and 17' of the bottom plate 10
:
q
.P~
105886~7
: and the valve plate 12, respectively, are of the same
shape and of the same dimensions so that the plates and
the beads can be used with a complimentarily shaped cas-
ing either to form a groove or a key forming portion as
will be described more fully in connection with Figure
2. Of course, other portions of the plates 10 and 12 may
be of different dimensions and shape depending on con-
siderations which need not be taken into account here.
Clearly, however, the advantages of the present inven-
tion reside in the fact that the shape and dimensions
of the molds of the plate required for the formation
of the groove and key connection is independent of the thick-
ness of the plate in the vicinity of the flow apertures.
As a result, the positioning of the butt joints 22 and
22' and the problem of manufacturing the plates with
the proper thickness in the vicinity of the flow aperture
16 and 16' can be effected in the conventionally simple
manner. Also, it should be noted that the beads 17 and
17' are located at a distance from the zone of highest
temperature and of the greatest temperature gradient
which is the location where chahges in the thickness of
the plate usually occur, the danger of cracks or fissures
occurring which lead to failure of the sealing functions
of these elements is greatly minimized if not entirely
eliminated.
~O
1058867
In Figure 2, another embodiment of the present in-
vention is illustrated which is substantially similar to
that of Figure 1 so that only the essential dif~erences
will be described below.
Figure 2 illustrates a three plate sliding closure
which is used, for example, on intermediate crucibles or
containers in continuous casting installations. Such ar-
rangements use, in general, a base plate 30, a perforated
stone casing 31, an outlet plate 32, an outlet casing 33
as well as the usual valve plate 34 which is disposed to
be longitudinally movable between the base ~ate 30 and
the outlet plate 32.
In the field of liquid metal handling, three plate
sliding closures have the advantage that the emerging jet ,
or stream of liquid metal does not move about relative to
the axis of the flow passages and thus spattering is mini-
mized when the valve plate 34 is moved between its open
and closed position. According to the present invention,
the base plate 30 and the outlet plate 32 have basically
the same shape and dimensions. The thickness 39 and 39'
of these plates in the area of flow apertures 35 and 35'
and the inside flanks 36 and 36' of the beads 37 and 37'
respectively, are larger than the basic thickness indicated
at 38 and 38' of the plates 30 and 32. With this arrange-
ment, the location of the butt joint 41 will be spaced at
1058867
a greater distance from the sealing surface 40 without
the width of the thick portion 39, 39' reaching a dimen-
sion which would be critical as a result of the above
mentioned consequences of heat expansion. The dimensions
S of the thicknesses 39 and 39' and of the base thicknesses
38 and 38' can, of course, be adapted to the requirements
of specific situations so that only a minimum of material
expenditure will be needed compared to the conventional
thicknesses of such plates thus resulting in a saving of
material costs.
The embodiment illustrated in Figure 2 demonstrates
clearly the advantage stemming from the fact that the beads
37 and 37' can be used both as a groove as well as a key
forming portion. Specifically, relative to the perforated
stone casing 31, the bead or key portion 37, on its interior,
defines a groove for the complimentarily formed part of the
casing 31 whereas the bead 37' functions as a key relative
to the complimentarily shaped portion of the outlet casing
33. Thus, according to the accepted practice in which the
key cooperating with the groove should be disposed in the
direction of flow of the liquid metal, this feature is ad-
vantageously retained together with the additional advantage
that the two plates 30 and 32 are interchangeable as they
can be shaped identically.
The use of the bead 37 as a key functioning portion
1058B67
of the connection with the outlet casing 33 is of par-
ticular advantage whenever the outlet casing serves as
an immersion outlet, that is to say, whenever the casing
has a pipe shaped extension which extends below the sur-
face of the bath leve~ as in a continuous casting process.Such immersion outlets must be capable of being quickly
installed and disassembled and, as is conventional, they
are attached without mortar on the outlet plate 32 or on
its housing indicated in broken lines about the plate 32.
With this arrangement, the funnel portion 42 could be
constructed with a key forming portion without difficulty
which would prevent leakages due to the absence of mortar
in the vicinity of the connection.
While the foregoing has been a description of the
preferred embodiments, it will be understood that varia-
. tions of the invention will be apparent to those skilled
in the art without departing from the scope of the inven-
tion as defined in thc app nded claiDs.
, ~ .
~: '
