Note: Descriptions are shown in the official language in which they were submitted.
The invention relates to a spout for a metal melt,
in particular a tapping spout of a blast furnace for the
production of pig iron, comprising a trough-shaped metal
jacket provided with a refractory lining accommodating the
metal melt.
The tapping of pig iron and slag from a blast furnace
takes place in periodic intervals. The pig iron and the
slag have to be supplied separately to the transportina
vessels available for the removal from the blast furnace
region. The separation of pig iron and slag is effected in
the main tapping spout from where the transfer to a sepa-
rate iron spout and a separate slag spout take place.
In recent times, tapping spouts with larae cross sec-
tions in which the pig iron remains also between the taps
have been successful. Such spouts make possible longer
standing times than those used so far, which have had to
be emptied after each tap.
On account of different expansions between the metal
jacket and the refractory brickwork, cracks will form in
the refractory lining in case of spouts for metal melts,
in particular with the spouts that have large cross sec-
tions. These cracks often extend not only through the wear
lining, with which such spouts are coated as a rule, but
also through the permanent lining as far as to the plate
armor. Such cracks constitute dangerous weak points of the
spout, since pig iron breakthroughs may occur as these
cracks are filled with molten pig iron (wha-t is called
"fins in the joints"), if the plate armor is melted through.
Pig iron breakthroughs not only cause considerable damage
to the spouts themselves and to the platform structure, but
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they also reduce the availability of the furnace. Further-
more, the operating personnel is jeopardized. The time and
expenditures necessary for a repair after a pig iron break-
through caused by joint fins are considerable.
For preventing joint fins that reach as far as to
the plate armor it is known to construct spouts with an ex-
treme thic]cness of the brickwork. Thereby attempts have
been made to cause -the pig iron penetratin~ a crack to
cool on account of the temperature drop in the brickwork
in order to avoid a damage to the plate armor. Apart from
the fact that the danger of joint fins reaching to the
plate armor cannot be completely eliminated by such a con-
struction, this solution necessitates high expenditures
for the brickwork.
From German Offenlegungsschrift No. 28 36 123 a tap-
ping spout is known which is composed of several parts,
the side walls and the bottom of the plate armor being
formed by individual plates that are non-positively con-
nected ina sliding manner on their common sites of contact.
The refractory lining of the spouts is braced on the front
sides stationarily in the pla-tform structure. Also with a
spout of this kind the danger of a pig iron breakthrough
caused by a joint fin exists. ~oreover, the non-positive
sliding of the plates of the plate armor contacting one
another during operation constitutes a problem.
The invention aims at avoiding these disadvantages
and difflculties and has as its object to provide a spout
of the initially defined kind, in which cracks and thus
joint fins as well as spout breakthroughs thereby caused
are prevented despite a wall thickness of the refractory
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lining as slight as possible.
The invention provides in a spou-t arrangement for a
metal melt, in particular a tapping spout of a blast furnace for
producing pig iron, of the type including a trough-shaped metal
jacket and a refractory lining provided on said metal jacket
and adapted to accommodate a metal melt, and at least one cavity
to receive a coolant to flow therethrough, the improvement which
is characterized in that a distribution box is arranged on one
end of said spout and ribs are provided within said at least
one cavity for conducting said coolant, said ribs departing from
said distribution box and extending in the longitudinal direc-
tion of said spout, and that air is provided as said coolant.
The cooling of the metal jacket causes it to expand
by a lesser degree -than the lining, so that the lining always
is under compressive strain during operation of -the spout.
Joints into which pig iron might penetrate are thus safely
avoided.
The cavity of the metal jacket is suitably subdivided
by the ribs into individual segments to which the coolant is
supplied independently.
According to a preferred embodiment discharge con
duits for the coolant are connected to one end of the spout, in
which conduits control valves are provided for controlling the
coolant flow.
A preferred feature of the invention is to be seen in
the fact that no strains should be formed within the spout by
its mounting, which might also be responsible for joint fins.
This object is achieved by fixing the metal jacket on -the base
by means of a fixed bearing in its lonyitudinal direction on
the one hand and by mounting it by means
-- 3
,.,
of rollers ~o as to be displaceable relative to the base
for accommodating longitudinal expansions on the other
hand.
Suitab]y, the metal jacket is inserted in a sectlonal
frame, the sectional frame advantageously comprising la-
terally cantilevered carriers on the upper rim of the me-
tal jacket, which carriers are suppoxted relative to the
base via rollers.
For preventing slanted positions of individual roll-
ers and a thus caused jamming of the same, the rollers aredivided into -two roller bodies by means of a peripheral
groove and are guided by means of a guide ledge arranged
on the base and engaging in the groove.
The invention will now be explained in ~ore detail by
way of two embodiments and with reference to the accompany-
ing drawings, wherein:
Figs. 1 and 2 are each a longitudinal section through
a spout, the fixed point of the spout once (Fig. 1) being
in the region of the pig iron tap and once (Fig. 2) being
provided on the opposite end;
Fig. 3 illustrates a section according to lines III-
III of Figs. 1 and 2 on an enlarged scale;
Fig. 4 is a view in the direction of the arro~ IV of
Fig. 3; and
Fig. 5 represents a partially sectioned perspective
view of the plate armor of the spout.
In the casing 1 of a blast furnace -to be used for the
production of pig iron, a tap hole 2 is provided, upon
which a tapping spout 3, i.e. a socalled "pool spou-t" fol-
lows. This spout comprises a metal jacket that is designed
-- 4 ~
as a plate armor of steel, a permanent lining 5, and awear lining 6 provided on the latter. In the lower spout
region, seen in the flow direction of the pig iron, a re-
taining brick 7 is arranged, which extends over the total
clear opening of the spout. By this retaining brick, which
serves for separating pig iron and slag, the slag floating
on the pig iron is retained and diverted into a slag
spout (not illustrated in the figures) via an outlet 3
provided in a side wall of the spout above the retaining
brick 7. The pig iron is flowing through a gap 9 provided
between the retaining brick 7 and the bottom of the spoutO
Below the retaining brick 7, the bottom of the spout is
elevated to a level 10 in the manner of a weir. On account
of the bottom level being elevated, the pig iron is re-
tained in the spout. The pig iron is discharged via this
elevated level 10 into an iron spout (not illustrated in
the figures).
The plate armor 4 is connected with the platform
structure either via a fixed point 11 in the region of the
tap hole 2 (Fig. 1) or via a fixed point 12 on the opposite
end in the region of the retaining brick 7 (Fig. 2). The
spout is arranged in a spout bed 13 attached to the cast-
ing pla~form. The plate armor 4 is composed of a welded
plate structure with a double wall, i.e. of an inner shell
4l and an outer shell 4". The two shells are connected by
reinforcement ribs 14 arranged in the longi-tudinal direc-
tion. On the outer side, the plate armor 4 is held together
at structurally dependent distances of about 700 mm each
by welded sectional frames 15 including laterally canti-
levered parts 15' in the region of the upper rim of the
spout. The outer ends of the cantilevered parts 15' areconnected by carriers 16 extending in the longitudinal
direction of the spout.
Rails 17 are mounted on sockets 13' of the spout bed
13, projecting upwardly from the mill floor. ~etween these
rails and running surfaces 18 provided on the lower rim of
the carriers 16, the spout 3, on eithex side, is journaled
via rollers 19 in the region of each sectional frame 15.
In order to achieve a parallel guidance of the rollers 19,
a groove 19' is turned into each of the rollers in the
middle thereof. This groove 19' engages in a guide ledge
20 fastened on the rails 17. On their two ends, the guide
ledges 20 are provided with braking-shoe like elevations
for delimiting the roller path.
A coolant is guided through the cavity 4''' enclosed
by the inner shell 4' and the outer shell 4" of the plate
armor 4, which absorbs the heat amount released by the
spout to conduct it away. Preferably, air is provided as
a coolant.
When using air~ the latter is supplied to the plate
armor 4 through several fans (not illustrated in the fiy-
ures), at least one of which serves as a stand-by fan,
via a compressed-air conduit 21. The compressed-air con-
duit 21 is divided into two partial conduits 21', 21" be-
fore being connected to the plate armor 4, which feed a
left-side distribution box 22 and a right-side distribution
box 23 via resilient in-termediate members (not illustra-
-ted). Each of these distribution bo~es supplies one half
of the spout with cooling air.
The reinforcement ribs 14 provided between the inner
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shell 4' and the outer shell 4" at the same -time serve
as air conducting plates and for subdividing the plate ar-
mor into segments independently supplied with coolant.
In the example illustrated in Fig. 5, a ~ottom seg-
ment and three wall segments are provided in each spout
half, whose discharge conduits are denoted by 24, 24' for
the bottom segments, and by 25, 25', 26, 26', 27, 27' for
the wall segments. In each discharye conduit a control
valve designed as a control flap is provided. The control
flaps are denoted by 28, 2~, 30, 31, 32, 33, 34, 35. By
adjusting the control flaps, it is possible to reach a dis-
-tribution of the amount of cooling air supplied via the
conduits 21, 21', 21" and the distribution boxes 22 and 23
to the various cooling segments in accordance with the
respective requirements. The adjustment of the control
flaps is effected via temperature measuring means arranged
in the individual cooling segments (not illustrated).
With the arrangement illustrated in Fig. 5, also the
region around the tap hole 2, i.e. the dome 36, is cooled
by the cooling air conducted away from the bo-ttom segments.
The possible applications of the invention are by no
means exhausted with the arrangement illustrated in Fig. 5,
but there are a number of feasible variations as to the
arrangement and subdivision of the cooling segments as
well as the extension of the cooling of the plate armor 4
according to the invention to various plant parts that
have to be cooled. According to an embodiment not illus-
strated, the plate armor could be provided with half -tubes,
i.e. tubes having a semicircular or other sec-tion, on its
outer side, these tubes being welded to -the plate armor in
a closely neighboring manner. These tubes, together with
the plate armor, then constitute the cavity through which
the coolant flows.
The advantage of the invention is to be seen primari-
ly in the fact that the plate armor, due to its being cool-
ed, during operation expands by a slighter measure only
than does the refractory lining of the spout, the refrac-
tory lining of the spout thus always being under pressure
tension. Therefore, no joints can form into which pig iron
might penetrate. In this connection, the one-part construc-
tion of the spout according to the invention is of a parti-
cular advantage.
The brickwork therefore may be designed relatively
thin; its durability is about 5 to 8 times the durability
of a conventional spout despite its slight wall thickness.
So far, the sealing brickwork has had to be renewed after
the tapping of 40,000 to 50,000 t of pig iron, whereas re-
pair work at the spout according to the invention is ne-
cessary only after the tapping of 250,000 to 320,000 t of
pig iron.
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