DEVICE FOR THE CONTROLLED COOLING OF HOT-BRIQUETTED DIRECTLY REDUCED IRON SPONGE

DISPOSITIF PERMETTANT DE CONTROLER LE REFROIDISSEMENT DE FER SPONGIEUX AGGLOMERE A CHAUD ET REDUIT DIRECTEMENT

English Abstract

In an arrangement for the controlled cooling of hot-briquetted direct-reduced
sponge iron in the form of an apron conveyor consisting of individual plates
and
located in a tank, the individual plate is designed as a conveyer trough,
wherein
at least one sliding plate each is located on the two opposed longitudinal
outsides
and the conveyor troughs are movably supported by means of the sliding plates
on slideways and connected by means of at least one chain. The invention
allows
to separate the drive and the bearing as the conveyor troughs are supported by
means of sliding plates and the drive acts directly on the conveyor trough by
means of at least one chain. As the translation elements are designed as
sliding
plates and slideways, the surface pressure is reduced to less than a hundredth
compared to wheels running on rails and the wear of the translation elements
is
thus reduced.

French Abstract

L'invention concerne un dispositif permettant de contrôler le refroidissement de fer spongieux aggloméré à chaud et réduit directement, qui se présente sous forme de convoyeur à tabliers situé dans un réservoir à liquides et composé de plaques individuelles. La plaque individuelle se présente sous forme de cuve convoyeuse (4) et sur chacun des deux grands côtés extérieurs opposés, il est prévu au moins une plaque coulissante (5 et 6). Les cuves convoyeuses (4) sont montées coulissantes sur des glissières (7) à l'aide de plaques coulissantes (5 et 6) et les cuves convoyeuses (4) communiquent avec au moins une chaîne (9). L'invention permet de parvenir à une séparation du mécanisme d'entraînement et du système de support, du fait que les cuves convoyeuses (4) sont soutenues à l'aide de plaques coulissantes (5, 6) et que le mécanisme d'entraînement sous forme d'au moins une chaîne (9) agit directement sur la cuve convoyeuse (4). La structure des éléments de translation qui se présentent sous forme de plaques coulissantes (5, 6) et de glissières (7) permet de ramener la pression de surface à moins d'un centième, comparativement à des roues roulant sur des rails. Il en résulte une diminution de l'usure des éléments de translation.

Claims

6
CLAIMS
1. Arrangement for the controlled cooling of hot-briquetted direct-reduced
sponge iron in the form of an apron conveyor consisting of individual
plates and located in a tank, characterized in that the individual plates are
designed as conveyor troughs, wherein at least one sliding plate is located
on two opposed longitudinal outsides and the conveyor troughs are
movably supported on slideways by means of the at least one sliding plate
and connected by means of at least one chain.
2. Arrangement according to claim 1, characterized in that each longitudinal
outside has one mounting plate, the at least one sliding plate including two
sliding plates, one being an upper sliding plate and the other being a lower
sliding plate connected to the mounting plate.
3. Arrangement according to claim 1, characterized in that the at least one
sliding plate includes two sliding plates, one being an upper sliding plate
and the other being a lower sliding plate, the two sliding plates being
located on each longitudinal outside and at each conveyor trough, the
upper sliding plate being thinner than the lower sliding plate.
4. Arrangement as claimed in claim 2 or 3, characterized in that each
conveyor trough is driven by means of the at least one chain and that a
detachable connection is provided between each conveyor trough and the
at least one chain.
5. Arrangement as claimed in claim 2 or 3, characterized in that that each
conveyor trough is driven by means of the at least one chain and is
provided with plug-in pushers, the plug-in pushers being detachably
connected with fishplates located on a bottom side of each conveyor
trough.
6. Arrangement as claimed in any one of claims 2 to 5, characterized in that
the conveyor troughs comprise brace plates.

7
7. Arrangement as claimed in any one of claims 2 to 6, characterized in that
it comprises side stops located on both sides of the conveyor troughs.
8. Arrangement as claimed in claim 7, characterized in that the upper sliding
plate and the side stop are separated by a horizontal distance which
amounts to maximally half an average diameter of the sponge iron
briquettes.
9. Arrangement as claimed in any one of claims 1 to 8, characterized in that
a spraying device is located in an area of the slideways that is located
above a water level of the tank.
10. Arrangement as claimed in any one of claims 1 to 9, characterized in that
the at least one chain is a round steel chain.

Description

CA 02278620 2006-11-15
1
DEVICE FOR THE CONTROLLED COOLINO OF HOT-BRTOUETTED
DIRECTLY REDUCED IRON SPONGE
The invention relates to an arrangement for the controlied cooling of hot-
briquetted
direct-reduced sponge iron in the form of an apron conveyor located in a tank.
An arrangement for cooling is known from the German patent specification DE 29
28 501
G2. This an-angernent is comprised of a quench tank and a conveyor placed
therein in
inclined position for transporting connected briquettes.
In the different prbcesses for the direct reduction of iron, solid
oxidiic=input material is
reduced to iron by_ means of reduction gases. The pellets or lump'ores formed
thereby
can only be storedunder special protective conditions as due to the
microporosity of the
products an exothermal reaction with atmospheric oxygen rriay occur.
Therefore, a hot-
briquetting plant has been connected downstream of several processes in order
to
compact the reduced material and, thus, to reduce the risk of reoxidation due
to the
surface which is reduced thereby_
Tlie briquettes forrned during hot briquetting have a temperature of approx.
750 C and
are cooled.Xo approx. 5O C in order to prevent self-ignition. However,
the.ener.gy stored
in the cooled briquettes must still suffice to dry them up.
Cooling is perforrrked in a quench tank, i.e. a tank filled with water, in
which wire mesh
belt conveyors or apron conveyors are located onto which the hot briquettes
drop. The
apron conveyors consist of perforated plates connected to one -another, to
which wheels
running on rails are mounted by means of pins. The plates are connected to one
another
by fishplate bush links. The conveyors are driven by a conveyor chain
connected with the
wheel axles.
The fines accompenyiilg the briquettes get onto the bottom of the tank as well
as onto
the rails through ttme holes in the plates. Combined with aggressive
substances in water,
with the high surface pressure acting on the supporting -surfaces of the
wheels at-.the
rails and with the r,adial stresses occurring, primarily the wheels and pins
are highly v-rorrm.
As the.,_!hO_ejs rura dry in_ front of the point of briquette discharge, the
afdrernentioned
conditions are agQravated by the alternation of wet and dry condition.

CA 02278620 2006-11-15
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The object of the invention is to develop a cooling system to reduce the wear
of
the conveyor elements and thus to increase the availability of the cooling
system
due to the lower maintenance expenditure. The design of the plates and of the
drive is to be modified so that less fines penetrate into highly stressed
areas.
Accordingly, there is provided an arrangement for the controlled cooling of
hot-
briquetted direct-reduced sponge iron in the form of an apron conveyor
consisting
of individual plates and located in a tank, characterized in that the
individual
plates are designed as conveyor troughs, wherein at least one sliding plate is
located on two opposed longitudinal outsides and the conveyor troughs are
movably supported on slideways by means of the at least one sliding plate and
connected by means of at least one chain.
A novelty of this invention is that the drive and the bearing can be separated
as
the conveyor troughs are supported by means of sliding plates and the drive
acts
directly on or trough by means of at least one chain.
As the translation elements are designed as sliding plates and slideways, the
surface pressure is reduced to less than one hundredth compared to wheels
running on rails. As a result, the wear of the translation elements is
reduced. The
sliding plates cover the slideways partly from the material flow so that less
fines
get directly onto the slideways and wear is further reduced.
Another feature of the invention is that one mounting plate each is located on
the
two opposed longitudinal outsides of the conveyor trough, to which mounting
plate one sliding plate each is fixed on its upper and lower sides. This type
of
mounting of the sliding plates on the conveyor trough enables the sliding
plates to
be easily exchanged if they are worn.
Another feature of the invention is that, if two sliding plates are placed on
each
longitudinal outside and at each conveyor trough, the upper sliding plate-seen
in
the direction of conveying-is thinner than the lower sliding plate. This
feature
takes into account that the lower sliding plate is subject to higher wear due
to the
loading of the conveyor trough and the direct action of fine material and the
upper

CA 02278620 2006-11-15
3
and lower sliding plates can thus be simultaneously exchanged, which results
in
increased plant availability.
Another feature of the invention is that the individual conveyor trough is
driven by
means of at least one chain, preferably a round steel chain, a detachable
connection being established between the conveyor trough and the chain.
Driving
by means of chains has the advantage that guidance of the conveyor troughs is
ensured by prestressing the chain. The detachable connection between the
conveyor trough and the chains facilitates plant maintenance.
The invention is further characterized in that the individual conveyor trough
is
driven by means of at least one chain, preferably a round steel chain, which
is
provided with plugin pushers detachably connected with fishplates located on
the
bottom side of each conveyor trough. The fishplate arrangement on the bottom
side of the conveyor trough has the advantage that the latter protects the
chains
engaging there from the direct action of sponge iron briquettes or fine
material.
Moreover, the use of round steel chains is advantageous as these are self-
cleaning.
Another feature of the invention is that the conveyor troughs are made of
brace
plates, which reduces the probability of deformation of the conveyor troughs
by
impact on the side stop.
The feature of one side stop being placed on both sides of the conveyor
troughs
serves for emergency guidance of the conveyor troughs in case of a sideward
motion resulting from loading the conveyor trough, on the one hand, and for
protecting the tank, on the other hand, because the side stop prevents the
conveyor trough from damaging the tank wall.
An advantageous feature of the invention is that the horizontal distance
between
the upper sliding plate and the side stop amounts to maximally half the
average
diameter of the sponge iron briquettes. This is to prevent the sponge iron
briquettes from dropping between the sliding plate and side stop, from getting
jammed there and locking the conveyor troughs, or from causing increased wear.

CA 02278620 1999-07-23
4
The last feature of the invention is that in the area of the slideways that is
located above
water level a spraying device is placed, which ensures uniform sliding
conditions for the
sliding plates and rinses deposits of fine material from the slideways into
the tank.
The invention is to be explained by an embodiment. The enclosed Figs. 1 to 3
display a
schematic representation of this embodiment.
Fig. 1 shows a vertical section through the tank in which the apron conveyor
is located.
Fig. 2 shows a detail of the apron conveyor according to Fig. 1.
Fig. 3 shows a section through A-A in Fig. 2.
Fig. 1 shows apron conveyor 1 located in tank 2 filled with water, arranged
together with
drag conveyor 3, which is not described in detail here. Hot sponge iron is
charged onto
apron conveyor 1 in the area of the left deflection of apron conveyor 1 where
the latter is
located below water level, conveyed further to the right according to the
arrow while
being cooled in water and discharged at the right end of tank 2. Drag conveyor
3 only
serves to discharge the fine material settled on the bottom of tank 2.
Fig. 2 shows the left part of apron conveyor 1 according to Fig. 1 with the
deflection
device for conveyor troughs 4. The individual plates of apron conveyor 1 are
designed as
conveyor troughs 4. The latter are preferably made of folded steel plate, in
particular of
so-called brace plates, which are resistant to radial stresses. The moving
direction of the
conveyor troughs is marked by the arrow. Conveyor trou,ghs 4 are fixed to
chains 9 by
which driving is performed. Furthermore, rolled section beams 8 are shown on
which
slideways 7 are mounted.
Fig. 3 shows a section through A-A in Fig. 2. Conveyor trough 4 shown on the
top moves
in conveying direction, and lower conveyor trough 4 in opposite direction. The
side walls
of conveyor troughs 4 are higher than the front and rear walls. On the two
opposed
longitudinal outsides of conveyor troughs 4 forming the two outsides of apron
conveyor 1
two sliding plates 5, 6 each made of wear steel are mounted. The two sliding
plates 5, 6
of one side are arranged one above the other so that lower sliding plates 5
are in
operation while conveyor trough 4 is moving in conveying direction and sliding
plates 6,
which are located on top in conveying direction, are in operation while
conveyor trough 4
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CA 02278620 1999-07-23
is moving in the opposite direction. One sliding plate 5, 6 each is fixed to
mounting plate
which is permanently connected to conveyor trough 4.
Conveyor troughs 4 are moved by means of sliding plates 5, 6 on wear-resistant
slideways 7 which are mounted on rolled section beams 8. Slideways 7 serve as
a sliding
basis for sliding plates 5, 6 and, together with rolled section beams 8,
absorb the
longitudinal forces and radial stresses resulting from belt movement.
Conveyor troughs 4 are driven through chains 9 provided with wear-resistant
plug-in
pushers. On the bottom side of each trough conveyor 4 fishplates 12 are
arranged in a
way that the pushers of chain 9 engage with the latter. The plug-in pushers
are secured
with clamping sleeves. The connection between chain 9 and conveyor trough 4 is
detachable. The tensile forces are transmitted to conveyor troughs 4 through
chains 9,
conveyor troughs 4 not being connected to one another. Conveyor troughs 4 thus
do not
have to absorb any tensile forces of the chains. The prestress of chain 9
supports
guidance of conveyor troughs 4.
Chains 9 are preferably designed as round steel chains. They are guided
between
slideways 8 beneath conveyor troughs 4 and largely protected by the latter
from being
contaminated.
Side stop 11 is placed on both sides of conveyor troughs 4. Due to the sponge
iron load,
conveyor troughs 4 may receive a short-time pulse which is largely directed
sidewards,
which is caught by the side stop so that the wall of tank 2 is also protected.
For those parts of slideways 7 which are located above water level, a spraying
device is
provided to ensure that slideways 7 have the same sliding conditions at all
points.
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Representative Drawing