Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates
a method and an apparatus for the drying of
metal turnings or scraps prior to such being used in melting
furnaces, and the hot-treatment of reclaimable or waste twirl
in general
Metal turnings both ferrous and non-rerrous7 Dust be
dried in order to remove their liquid content before they are
used in melting furnaces. In fact turnings from machine
tools always contain liquid of the order of 3 - 55~ on verge
and comprising the residues of cutting oils or coolants
solvents, additives water, etc. If these liquids are not
removed in advance they tend to cause agglo~exations or
; clumping when the turnings are loaded in-to melting furnaces
and to form compact layers on the surface of the molten
; 15 metal. the gases which are produced by the presence of
such liquids also tend to give rise to explosions, ~lare-ups
and toxic fumes, and when in contact with the metal they
give rise to the formation of oxides and slag with a
consequent loss of metal.
It has been found that the loss of metal on melting
; is directly proportional to the liquid content of the initial
turnings. An investigation based on many fusion tests with
brass turnings has shown that there is a loss of about 3~0
of molten metal when the initial tllnings have a high liquid
content, against a loss of 2 - 39~ when dried turnings are
used. Various apparatus have already been proposed in which
the material which is to be cried is passed into a drier and
heated directly by a heat source which burns a combustible gas,
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and these apparatus for the drying of materials such as
turnings, in addition to processing involving washing
with solvents, cen-trifugation, etc., have nevertheless
in the main proved themselves to be sources of waste and
pollution. When the material is heated the liquids
contained within i-t evaporate and therefore form vapors.
Some of these burn in the drier when in contact with the
flames used to heat the material while the remainder are
collected and passed out of -the drier where they
are normally burnt in another afterburner using another
fuel.
Units of this type are rather complex
and cumbersome and involve both a high energy consumption,
and thus high operating costs, partly because they are
not able to utilize the calorific content of the vapors
produced, which is high, and also require apparatus for
cooling and filtering of the fumes before they
are discharged -to -the atmosphere in order to prevent
pollution. The afterburner also frequently clogs up as
a result of the dust carried by the fumes and requires
periodical shut-downs to parent cleaning to be effected.
To be specific apparatus of the known type are,
in addition to having inconveniences and disadvantages
in operation, rather complex and cumbersome and normally
require special foundations or in any event require
masonry structures which place a large burden on the costs
of the units in addition to high operating costs.
According to the present invention, there is
provided an apparatus for drying solid waste and scrap
material to remove liquid contaminants therefrom, comprise
in the combination of a drum having an inlet end for
receiving material containing liquid contaminants and
; an outlet end for discharging the decontaminated matte-
fiat, a transporter for moving the material lengthwise
of the drum from its inlet end to its outlet end, the
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drum having an impervious side wall to shield
the material passing -there through from atmosphere outside
the drum, a furnace through which the drum passes, the
furnace having a gas burner for directing hot burning
gases against -the side wall of the drum to heat the mate-
fiat passing -there through, and means for injecting into
-the drum an inert gas to maintain a protective atmosphere
within the drum to prevent oxidation of the material, the
drum and the -transporter being inclined upwards from said
inlet end to said outlet end; the upper end of said drum
being connected by a pipe to a drier in order to pass fumes
and vapors which are to be burnt into said drier, the drum
extending on either side of the drier in a tubular portion
which encloses at least the lower part of said drum, and
in which said drier has a vertical axis and a hopper bottom
for collection of dust and is provided with a transporter
for the removal of such dust.
Preferably, the apparatus comprises a vertical
axis furnace or drier in which a rotating drum is mounted
-transversely and incorporates a transporter for forward
movement of the material, in particular metal turnings,
wire scraps, rubbish, etc. which has to be treated. The
material is heated indirectly by the drum, in a counter-
current or co-current fashion, in order to evaporate its
liquid content, while a protective atmosphere is constantly
maintained within the drum through the injection of an
inert gas to prevent oxidation of the material. The vapors
leaving -the drum are passed into the drier and are burnt
there to heat the material passing -through the drum and
render -the operation of the unit self sufficient
Preferably, as an alternative the vapors leaving
the drum can be treated to recover their oil content, e.g.
by distillation.
According to the present invention, there is
also provided an apparatus for drying solid waste and scrap
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material to remove liquid contaminants therefrom,
comprising -the combination of a drum having an inlet end
for receiving material containing liquid contaminants and
an outlet end for discharging -the decontaminated material,
a transporter for moving the material lengthwise of the
drum from its inlet end -to its outlet end, the drum having
an impervious side wall to shield the material passing
there through from atmosphere outside the drum, a furnace
through which -the drum passes, the furnace having a gas
burner for directing hot burning gases against the side
wall of the drum to heat the material passing there through,
and means for injecting into the drum an inert gas to
maintain a protective atmosphere within the drum to prevent
oxidation of -the material, -the drum and the transporter
being inclined upwards from said inlet end to said outlet
end; the upper end of said drum being connected by a pipe
to a drier in order to pass fumes and vapors which are
to be burnt into said drier, an air-flow external coil
heat exchanger being provided in the vicinity of the upper
end of said drum in order -to exchange heat with the
material and cool the material before the material is
discharged from the drum/transporter and a sleeve secured
within said drum bounding an axial duct for separation
of the fumes and vapors from the material.
Preferably, another object of the present invent
lion is to provide an apparatus which uses a single burner
and in which fume filtering devices can be reduced, if
not done away with, with the advantage of greater
simplicity and a reduction in both the cost and
the operating and maintenance costs of the apparatus.
Preferably, another object of this invention
is to provide an apparatus which comprises a
drum/transporter which can be inclined upwards in order
to assist the fumes or vapors produced when the material
; 35 is dried to escape and to simplify both -the addition and
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removal of material from the -transporter drum, avoiding
-the need for lifting gear at the inlet and outlet of the
said drum. This does not however rule out the possibility
that the drum and the transporter included within it may
be arranged horizontally or may be inclined downwards
towards the outlet for the material while remaining within
the scope of the invention.
According to -the present invention, -there is
also provided an apparatus for drying solid waste and scrap
material -to remove liquid contaminants therefrom, comprise
in the combination of a drum having an inlet end for
receiving material containing liquid contaminants and an
outlet end for discharging the decontaminated material,
a transporter for moving the material lengthwise of. the
: 15 drum from its inlet end -to its outlet end, the drum having
an impervious side wall to shield the material passing
there through from atmosphere outside the drum, a furnace
through which the drum passes, -the furnace having a gas
burner for directing hot burning gases against the side
wall of the drum to heat the material passing there through,
and means of injecting into the drum an inert gas to
maintain a protective atmosphere within -the drum to prevent
oxidation of the material, the burner being constructed
to burn either a combustible gas or vapors leaving the
drum, said burner comprising a gas burner having a pilot
surrounded by a first annular chamber into which the vapors
which are to be burnt are fed and a second annular chamber
into which the air for combustion flows, the gas flow being
reduced to that of the pilot after combustion of the vapors
has been initiated.
According to the present invention, there is
also provided an apparatus for drying solid waste and scrap
material to remove liquid contaminants therefrom, comprise
in the combination of
a drum having an inlet end for receiving material
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containing liquid contaminants and an outlet
end for discharging the decontaminated
material,
a transporter for moving the material lengthwise
of the drum from its inlet end to its outlet
end,
the drum having an impervious side wall -to shield
the material passing there through from atmosphere
outside the drum,
lo a furnace through which the drum passes, the
furnace having a gas burner for directing hot
burning gases against the side wall of the drum
to heat the material passing there through,
means for injecting into the drum an inert gas
to maintain a protective atmosphere within the
drum to prevent oxidation of the material, and
means for conducting from the outlet end of the
drum to the gas burner the vapors formed as the
liquid contaminants evaporate from the material
to be ignited at the gas burner for heating the
material passing through the drum.
According to the present invention, there is
also provided a method of drying solid waste and scrap
material comprising
moving the material internally of a container
having a side wall adapting to exclude from the
material external atmosphere and oxygen
containing gases,
applying burned vapors to the container
externally thereof to heat the material coursing
-through the container to evaporate liquids from
the material into vapors,
introducing an inert gas into the container to
maintain a protective atmosphere against
; 35 oxidation of the material and to absorb vapors
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evaporated from the material.
conducting the vapors out of said container and
away from the material, and
burning the vapors conducted out of said
container for application externally of
the container whereby the caloric value of the
liquids is utilized to produce usable heat.
The invention will be described further by way
of example with reference to the accompanying drawings,
in which:
Figure 1 is a schematic elevation illustrating
the drying apparatus;
Figure 2 is a vertical section through a drier
and drum which extends within it;
Figure 3 is a cross-sectional detail of the drum
in the vicinity of the inlet for the material and inert
gas to maintain a protective atmosphere within -the drum
itself;
Figure 4 is a cross section of -the burner of
the drier or furnace and
Figure 5 is a transverse cross-section along
the line indicated by arrows V-V in figure 2.
A drier or furnace 1 is illustrated in which
there is transversely mounted a drum 2 which encloses a
transporter 3 for forward movement of -the material which
is to be dried.
the drier or furnace 1 defines a chamber 4 of
a cylindrical or other shape having a vertical axis and
has at its top a gas burner 5 which is mounted
tangentially. The bottom 6 of chamber 4 may be flat or
preferably it the shape of a hopper.
The drum 2 may be arranged with its axis inclined
upwards from its inlet 7 for the loading of the material
which is to be dried and extends upwardly to its end 8
from _ _
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which the dried material and the foe or vapors produced
during Dunn escape.
Drum 2 extends concentrically in a tubular portion
9 provided in the shell 3 of the drier and across and on
either wide Or chamber 4.
Drum 2 may be rotatable and on which case its two
ports rest on supporting bearings 11 on opposite sides of
the drier 1 and the drum 2 is rightable driven by chain
drive 12 driven by a motor/reduction err 13.
the transporter 3 for the material may be constructed
; of a coiled strip or a screw plate which advances in the
Norm of a screw 14 fixed to the internal surface of drum 2
over its entire length for movement of the material from the
loading inlet 7 to the end of the drum 8 where the dried
materiel is discharged
The inclination of drum 2 and transporter within it
- avowers separation of the fumes or Yippers from the material
which is being dried, end escape of the vapors from
drum 2.
This separation between fumes and vapors and materials
is assisted and virtually ensured by means of a sleeve 17
which is fixed to the summit of the last turn of the screw
transporter 14 within drum 2 see Fig 2). this sleeve 17
together with drum 2 bounds a longitudinal-annul æ passage
for the material and axially a duct 18 o'er fuses and vapors
only quiz helps to maintain the temperature of the fumes
; :; or vapors almost unchanged and on the other hand can cool
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the material before it it discharged from drum 2 to
collector device 16.
In order to achieve this cooling Or the material,
the latter part of drum 2 may be surrounded by a coil
heat exchanger 19 through which cooling air oireulates
and which ends in an aspirator 19'~
The cooling air is circulated counter-currently with
respect to the matexi~l and the hot r leaving the
exchanger 19 can advantageously be used for the air
supply to burner 5 operating within drier 1.
Although the inclined ~xrangement of drum 2 and
transporter 3 within-it-i~ apparently the most advantageous,
this does not however rule out the possibility thaw drum 2
might for some reason require to be mounted hori30ntally
or inclined downwards towards the discharge region for the
Maxwell, and the-d~Nm-itself:-may_be-stationary or
vibrating, without going beyond the scope of tube invention -
SimilP~ly transporter may comprise a Conner belt or a
roller lane (not shown) instead of the screw plate.
: 20 In any event inert gas is passed into chinaberry 2' defined
by the rotating drum 2 in order to maintain a protective
atmosphere within the drum and to prevent oxidation of the
material which is being dried. The injection of inert gas
into chamber 2' of drum 2 may be achieved ennui by means of
an injector 112 which is aligned with the said drum at the
material inlet 7 - see Fig. 3.
` the opposite end B of drum 2 is on the other hand provided
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with a suction hood 20 to collect the fumes or apprise
which separate from the material being dried. The
hood 20 it connected by means of a pope 21 to the top of
the drier or furnace in order to pass the fumes or
vapors into it. The inlet 22 (Fig. 4) or the funs or
appear into the drier is provided in or adjacent to the
region it which fuel burner 5 is in operation Jo that the
flame from the latter can also initiate combustion of the
said fumes ox vapors.
Advantageously the fumes or vapors are passed via
pipe 21 see Fig. 4) into an annular chamber 41 surrounding
the body of burner 5 and bounded by a sleeve 42~ A second
annular chamber 43 is provided concentrically outside
annular chamber 41 and into this there flows the air for
combustion which may, for example be the air leaving heat
- exchanger 19 mentioned above, via an opening 44. A system
: of to Kind waxes it possible to use fuel burner 5 to start
up the apparatus until the drying process is established and
fumes or vapors are being produced in the drum
when the flow of such fumes or vapors to the drier is
regular and sufficient they are ignited, the fuel supplying
~uLrner 5 is reduced to the flow required to keep the pilot
flame of the said burner alight. All the heat required by
the process is then provided exclusively by combustion of
the fumes or vapoux deriving from drying of tune material.
In practice the hot vapors which are produced initially
by the burning of fuel in the burner and subsequently by
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burning of the vapors which are released during drying of
the material and leave the drum pus over the external
surface of drum 2 and pass along a passage 23 preluded
between the rotating drum and tubular portion 9 and aye
discharged via a pipe 24 placed near to the mouth 7 of the
drum. on the example shown the transfer of heat
; between the fumes and the material which is to be dried
occurs counte~curr~ntly and indirectly via the drum,
without any direct contact between the products of
- 10 combustion and the material. the material and the Yipper
which are released in the drum are thus protected against
contact with the flaxes, and as a result of the atmosphere
. of inert gas which is produced within the drum chamber
: the material is not subjected to oxidation.The fumes which flow out try pipe 24 are then
` passed (Sophie l) into a heat e~changer-25 which seduce
their temperature to the required-Yalue and then to a- .
cyclone 26 for precipitation of the dust and-then finally,
but only if necessaryj-into a bag filter 27 before being
discharged to the atmosphere via-a tack 28 which acts in
association with all the blowers driving the circulation
of vases within the unit.
The simplicity and the junctional capacities of the
apparatus and the possibility of profitably and advantageously
using the fumes or vapors originating from the drying of the
material as a fuel for direct use in the drier are obvious
from what has been said above. The material is also treated
in a closed chambert7 separate from the products of
combustion which mixes it possible to maintain a
protective atmosphere which prevents oxidation of the
material and reduces the loss of metal when this is
melted in melting-down furnaces
The apparatus described can be provided with other
devices which make it even more functionally effective and
advantageous.
One of these devices comprises the hopper bottom 6
which is provided as mentioned above in the bottom of
chamber 4 of the drier. As a result of the vertical
arrangement of chamber 4 the dust and solid particles
circulating within the drier-can settle out into this hopper
bottom 6 from which they can be removed at intervals by means
of a transporter 29 fitted there Fig. 2. This mixes it
possible to keep the drier adequately clean without the-need
for the unit to be-shut-down for direct access-by operators
Within the tubular-portion 9 in Rich drum 2 is mounted
a scraper 30 is mounted in order to act upon the external
surface of the dim and keep-it freedom solid deposits.-
This scraper 30 is for example, mounted on arms-31 so that
it can be mowed and positioned radially with respect to the
drum (see Fig 5). A fixed scraper 32 on the other hand
is mounted on the surface of drum 2 and this when it
; - 25 - rotates with the drum removes solid deposits from the internal
; surface ox the tubular portion in order to keep passage 23
clear for the fumes which air directed towards the discharge
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pipe 24.
finally cold air intake with a controlled aperture
it mounted on the shell of the drier in order to prevent
overheating of the drier
It should be noted that the vapors leaving the drum
or at least some of them can be treated to Recover
cool m g oil and/or other component using suitable
distillation or like processes.
As stated Ahab the apparatus is suitable also for the hot-treat=
mint of wire snaps in order to separate the metallic portions,
erg. copper or aluminum, from the plastics or rubber coating.
Finally the same apparatus may be use for the treatmentiof urban
spa solid refuses o wastes before they are evacuated.
