Note: Descriptions are shown in the official language in which they were submitted.
9 ~
Method and equipment for reprocessing fragment-
type fractions and/or free-flowing materials
.
The invention relates to a method for reprocess-
ing loose materials, in particular fragment-type
fractions and/or free-flowing materials, and to equipment
for carrying out the method, in which the fragment-type
fractions or free-flowing materials are reprocessed by an
appropriate comminuting and/or wet treatment and by a
subsequent thermal treatment.
A special field of application of such a method
is the reprocessing (recycling) of loose materials. These
loose materials can, for example, arise in the form of
metal-containing fragment-type fractions due to organic
or chemical binders or also in the form of a free-
flowing, used foundry sand. The foundry sand can here
arise in the form of a cold-resin monosystem or in the
form of mixed sand consisting of green sand and core sand
residues or else in the form of core fragments or the
like.
The disposal of the abovementioned loose mate-
rials arising in relati~ely large quantities by landfill
has recently led to increasing difficulties, and espe-
cially in foundry technology, for reasons of protection
of the environment and for reasons of the landfill volume
still available and also for reasons of economics (for
e~ample because of the costs of new sand).
For reprocessing of loose materials, in parti-
cular foundry sands, a method is generally known, in
which the so-called binders are removed essent.ially by an
appropriate wet treatment and the binders are then
neutralised by centrifuging, so that the sand and the so-
called fine sludge essentially consisting of binder
residues and quartz dust are separated. The residue
binder contents are burned by an additional thermal
treatment in a continuous shaft furnace.
The present invention deals with the problem of
an economical re-utilisation of loose materials, such as
they arise, for example, in the form of metal-containing
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fragment-type fractions due to organic or chemical
binders or in the form of free-flowing, used foundry
sands formed as various types of sand, the invention
being based on the object of indicating a method and
equipment ~or car~ying out the method, by means of which
the loose materials arising as Iractions or sand are
reprocessed to give a re-utilisable quality approximately
as new.
This object is achieved by the method according
to the invention when, for the thermal treatment, the
loose material is passed throu~h an externally heated
piping system and then subjected to a gaseous medium for
a step of screening and separating off the residual gases
and fines.
A preferred method is characterised by the
combination of the following features,
a) the loose material is cleaned by removing the
adhering dirt particles, in the washing vessel
filled with an appropriate cleaning liquid, by
ultrasonically generated vibrations, whereby the
cleaning liquid is continuously moved, and is then
dried,
b) the loose material cleaned and dried in this way
then being passed for the thermal treatment through
an externally heated piping system rotatable about
its longitudinal axis and subsèquently being
subjected to a gaseous medium for a step of
screening and separating off residual gases and
fines.
The equipment according to the invention for
carrying out the method consists of a drum-type furnace
with a heatable combustion chamber for the thermal
treatment of loose materials, in particular fragment-type
fractions or free-flowing materials, and is characterised
in that a piping system mounted for rotation about its
longitudinal axis and interactively connected to a drive
and having at least one spirally formed pipe is provided,
which is designed for receiving the loose material at one
end and discharging it into an associated chamber at the
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other end.
Further features of the invention can be seen
from the following description in conjunction with the
drawing and the patent claims.
The invention is described below in more detail
by reference to the drawing, in which:
Figure 1 shows a first illustrative embodiment, repre-
sented as a flow diagram, of a reprocessing
plant essentially comprising a washing vessel
and a drum-type furnace,
Figure 2 shows a second illustrative embodiment, repre-
sented as a flow diagram, of a reprocessing
plant essentially comprising a rasping pot and
a drum-type furnace,
Figure 3 shows a piece of pipe represented in a profile
cross-section for a piping system arranged in
the drum-type furnace, and
Figure 4 shows a second washing device, represented in
sectional view and diagrammatically, for the
reprocessing plant according to Figure 1.
Figure 1 shows, as a first illustrative embodi-
ment, a reprocessing plant, represented essentially as a
flow diagram, for loose materials which are fed, for
example, in the form of fragment-type fractions and/or
free-flowing materials to the plant. The free-flowing
materials are, for example, various types of sand, such
as they arise in the form of a cold-resin monosystem or
in the form of mixed sand consisting of green sand and
core sand residues, or else in the form of core fragments
or the like, as so-called foundry by-products.
The plant designated as a whole by 50 essentially
comprises a so-called washing vessel 10, a first and
second tra~sport and conveyor belt 5, 6, 7 and 11, an
ultrasonic device 15 and a drum-type furnace 20. The
washing vessel 10 contains a certain liquid which is hèld
in continuous motion by the ultrasonic device 15 inter-
actively connected to the washing vessel 10.
In a further variant of the plant 50, it is also
possible for the washing vessel lO to be associated with
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a rasping vessel which is not shown in Figure l and which
is provided with appropriate comminuting elements, and by
means of which the products delivered in the form of core
fragments are comminuted and then fed as sand to the
washing vessel lO.
The ultrasonic device lS comprises, in ~he
illustrative embodiment shown, two sonic transducers 16
and 17 which are arranged on the washing vessel 10 at a
mutual distance and which are connected via lines 16' and
17' to a generator 18. The generator 18 is connected via
a lead l9 to the mains supply.
It should here be pointed out that, to achieve
optimum efficiency in an illustrative embodiment not
shown, a plurality of sonic transducers 16, 17 arranged
at a mutual offset are provided on the washing vessel 10
at the bottom, not designated in detail, or on the side
walls of the washing vessel lO, depending on the size and
the throughput.
In the generator 18, the mains frequency fed via
the lead 19 is converted into a corresponding high
frequency which is fed via the lines 16', 17' to the
respective sonic transducer 16, 17. Before the sonic
transducers 16, 17, the electrical vibrations are conver-
ted into mechanic vibrations of approximately the same
frequency.
The mechanical vibrations thus generated are
transmitted by means of the sonic transducers l~, 17 to
the washing vessel lO formed as a sonic body and from the
latter in the form of a so~called longitudinal wave 16"
and 17" to the liquid present therein and designated 10'.
At sufficient intensity, so~called cavitation bubbles are
formed by the vibrations diagrammatically shown by the
arrows 16", 17".
The build~up and the subsequent bursting of these
cavitation bubbles effects essentially a brush~like
treatment and the chemical composition of the liquid lO'
effects a corresponding detachment of the binders and
further dirt particles from the sand fed to the washing
vessel lO. The dirt particles settle at the bottom as
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so-called sllldge materials designated 10".
The sludge materials lO" are fed via a return
line 33 appropriately co~nected to the vessel 10 to a so-
called filter press 32. The solids thus formed are ~ed
for further utilisation in the direction of the arrow 34
to an appropriate unit tnot shown), while the li~uid is
fed via a line 34 in the direction of the arrow 34' to
the vessel 10.
As the so-called cleaning liquid lO' an aqueous
solvent liquid is preferably used, for example. The
aqueous bath, for example a bath having an alkaline pH
value of 7-14, has an cptimum cleaning effect and,
moreover, does not pollute the environment and is largely
degradable.
By means of the transport and conveyor belt 5, 6,
7 partially arranged in the washing vessel 10, the
cleaned sand is fed to a vessel 4 shaped in the form of
a hopper and then via a feed line l to a piping system
40, which is appropriately arranged in a vessel 21 of the
drum-type furnace 20. The vessel 4 is connected via a
line 4' to the interior 21', designed as a combustion
chamber, of the vessel 21, so that the sand cleaned in
the washing vessel 10 and still moist in this phase is
largely dried.
In a further illustrative embodiment, represented
hy the broken lines, however, it is also possible for an
appropriate hot-air blower 46, which is connected to the
vessel 4 via a line 47, to be associated with the vessel
4 for drying the sand. Between the hopper-shaped vessel
4 and the vessel 21, a gate valve 2 can be arranged which
can be actuated by a pistontcylinder unit 3 appropriately
controllable for openiny and closing the gate valve 2.
At the front part A, designed as an inlet, of the
vessel 21, a burner 31 is arranged, by means of which the
3S interior 21', designed as a combustion chamber, of the
vessel 21 is heated. In an illustrative embodiment not
shown in more detail, a plurality of heating elements,
distributed in the circumferential direction of the
vessel and arranged at a mutual distance are provided in
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the longitudinal direction along the vessel 21. The
oriented arrangement of the heating elements in the
longitudinal direction is preferably subdivided into two
or more zones, whereby an optimised controllable regula-
tion of the heating of the interior 21' can be achieved.
At the rear part B, designed as an outlet, of the
vessel 21, a first chamber 26, a filter device ~2, a fan
25, a second chamber 24 and a grate 23 arranged between
the first chamber 26 and the second chamber 24 are
provided. The filter de~ice 22 is connected via a line 27
to the inle~ A of the vessel 21, with interposition of a
fan 28. In the illustrative embodiment shown, the second
chamber 24 is connected via a line 29 to a receiver 30.
The feed line l can be connected to the piping
system 40 via a distributor element 35 which is shown
diagrammatically, arranged in the combustion chamber 21'
of the vessel 21 and, for example, designed in the manner
of a container. The piping system 40 comprises at least
one, but preferably a number of spirally wound pipes 41,
which are each connected at one end to the feed line 1 or
to the distributor element 35 and at the other end to the
second chamber 26. The individual, spiral-type pipe 41 or
else ~he complete piping system 40 is interactively
connected to an appropriately associated, diagrammatic-
ally represented drive 42 and is mounted in the combus-
tion chamber 21' to be rotatable in the direction of the
arrow Z about an approximately horizontal longitudinal
axis X.
In a preferred illustrative embodiment, the
piping system 40 is arranged in the combustion chamber
21' of the vessel 21 around a longitudinal axis X' which
is ascending relative to the longitudinal axis X, or
around a longitudinal axis X' which is descending rela-
tive to the longitudinal axis X. The angle ~ or ~',
formed between the horizontal axis X and between the
ascending or descending longitudinal axis X' or X", is in
each case of the order of magnitude of about 10 to 30.
The vessel 21 is mounted, for example, on two
foundations 45, 45' located at a mutual distance in the
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axial direction of the vessel.
The vessel 21 can be mounted on the two founda-
tions 45, 45' in a hori~onta:L plane. In the case of
horizontal mounting, the piping system 40 is arranged in
the combustion chamber 21' at the ascending angle
described above and designated ~, or else at the
descending angle designated ~.
In the case of a coaxial arrangement of the
piping system 40 in the combustion chamber 21', the
vessel 21 is arranged and mounted on the two foundations
45, 45' with its longitudinal axis 1 at an analogous
descending or ascending angle.
In ~igure 2, a second illustrative embodiment of
a plant is shown which is essentially represented as a
flow diagram and designated 150 as a whole and which
serves, for instance, for the reprocessing of sand core
fragments or the like. The plant 150 comprises essen-
tially a so-called rasping pot 110, a correspondingly
associated transport and conveyor belt 111 and a drum-
type furnace 120.
The rasping pot 110, which is shown diagrammatic~ally and is driven in rotation about an essentially
vertical axis Y in the direction of the arrow Y' by means
not shown in more detail, has a receiving vessel 110'
which is provided on the inner periphery and at the
bottom with appropriately arranged comminuting elements
113 designed approximately in a blade-type manner. By
means of the comminuting elements 113, the sand core
fragments sent via the transport and conveyor belt lll
are comminuted appropriately. The sand thus formed and
still containing all the binders or the like drops from
the screen-type bottom 114 of the rasping pot llO into a
hopper-type vessel 104 and is then fed via a feed line
lO1 to a vessel 121 of the drum-type furnace 120. A gate
valve 102, which can be actua~ed by a piston/cylinder
unit 103 appropriately controllable for opening and
closing the gate valve 102, can be arranged between the
hopper-type vessel 104 and the vessel 121.
The drum-type furnace 120 is designed analogously
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to the drum-type furnace 20 described above in conjunc-
tion with Figure l.
At the front part A', designed as an inlet, of
the vessel 121, a burner 131 is arranged, by ~eans of
which the interior 121', designed as a combustion
chamber, of the vessel 121 is heated.
At the rear part s~, designed as an outlet, of
the vessel 121, a first chamber 126, a filter device 122,
a fan 125, a second chamber 124 and a grate 123 arranqed
between the first chamber 126 and the second chamber 124
are provided. The filter device 122 is connected via a
line 127 to the inlet A' of the vessel 121, with inter-
position of a fan 128. In the illustrative embodiment
shown, the second chamber 124 is connected via a line 129
to a receiver 130.
The feed line 101 can be connected to the piping
system 140 via a distributor element 135 which is shown
diagrammatically, arranged in the combustion chamber 121'
of the vessel 121 and, for example, designed in the
manner of a container. The piping system 140 comprises at
least one, but preferably a number of spirally wound
pipes 141, which are each connected at one end to the
feed line 101 or to the distributor element 135 and at
the other end to the second chamber 126. The individual,
spiral-type pipe 141 or else the complete piping system
140 is interactively connected to an appropriately
associated, diagrammatically represented drive 142 and is
mounted in the combustion chamber 121' to be rotatable in
the direction of the arrow Z about an approximately hori-
zontal longitudinal axis X.
In a preferred illustrative embodiment, thepiping system 140 is arranged in the combusion chamber
121' of the vessel 121 around a longitudinal axis X'
which is ascending relative to the longitudinal axis X,
or around a longitudinal axis X" which is descending
relative to the longitudinal axis X. The angle or ',
formed between the horizontal axis X and between the
ascending or descending longitudinal axis X' or X-' is in
each case of the order of magnitude of about 10 to 30.
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The vessel 121 is mounted, for example, on two
foundations 1~5, 145' located at a mutual distance in the
axial direction of the vessel.
The vessel 121 can be mounted on the two founda-
S tions 145, 145~ in a horizontal plane. In the case of
horizontal mounting, the piping system 140 is arranged in
the combustion chamber 121' at the ascending angle
described above and ~esignated ~, or at the descending
angle designated ~.
In the case of a coaxial arrangment of the piping
system 140 in the combustion chamber 121', the vessel 121
is arranged and mounted on the two foundations 145, 145'
with its longitudinal axis X at an analogous descending
or ascending angle.
The pipe cross-section of the individual pipe 41
of the pipe system 40 installed in the drum-type furnace
20 according to Figure 1, or of the individual pipe 141
of the pipe system 140 installed in the drum-type furnace
120 according to Figure 2, can be of different shapes.
The pipe cross-section of the pipe, which can be
formed into a spiral, is, for example, annular, square,
rectangular, triangular, polygonal, square with a
parallel-offset or t~e like. The essential point for the
cross~sectional shape is, however, that the individual
2~ spiral has the greatest possible heat transfer area.
Figure 3 shows, as an illustrative example, a
pipe 41, 141 with a square cross-section, offset in
parallel, for the pipe system 40 or 140, and the
parallel, mutually opposite surfaces 38, 38' and 39, 39',
which enclose the interior designated 37, can be seen.
In Figure 4, a washing device designated 210 as
a whole is shown in a diagrammatic sectional view and as
a second illustrative embodiment, and an appropriately
associated transport and conveyor belt 211, a first
vessel 90, a first screen 91 which can be moved to and
fro in the direction of the arrow 91' by means not shown,
an appropriately associated second vessel 92 preferably
of hopper-type shape and a second screen 93 which can be
moved to and fro in the direction of the arrow 93' can be
lO- 20~
seen.
The parts 90, 91, 92 and 93 are associated with
a washing vessel 75 which essentially comprises a cylind-
rical body 75' arranged upright between two mutually
spaced flanges 76, 76'. A filter element 77 is arranged
in the interior 78 of the steel shell or of the cylind-
rical body 75' designed as a transparent body for visual-
ising the function. The interior of the cylindrical body
75' is subdivided by the filter element 77 into a first
chamber 79 for the actual loose material (not shown) and
into a second chamber 78 for detached sludge materials
210".
At least one sonic transducer 80 interactively
connected to an appropriately associated ultrasonic
device 85 is arranged in the chamber 79 of the cylind-
rical body 75'. In an embodiment variant not shown, a
plurality of sonic transducers 80 in a mutually offset
arrangement and interactively connected to the ultrasonic
device 85 can also be provided.
In a manner not shown in more detail, the cylind-
rical body 75' is joined with seals to the two flanges
76, 76', an opening 74 for charging the loose material
being provided in the upper flange 76 and a conically
shaped opening 74' for emptying being provided in the
lower flange 76'.
A line 97 arranged with a seal on the lower
flange 76' and having a shut-off valve 96 is also connec-
ted to the washing vessel 75. The line 97 leads to an
appropriately associated vessel 95 preferably provided
with a screen 94.
A line 99 and, with insertion of a valve 96', a
return line 233 communicating with the line 99 are
connected to the vessel 9S. For the thermal treatment,
the cleaned sand is fed via the line 99 in the direction
of the arrow 99' to the piping system 40 (not shown in
Figure 4), while the liquid is fed to an associated
filter press 232 and from the filter prPss 232 via a line
234 in the direction of the arrow 234' back into the
washing vessel 75.
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A line 98, through which the sludge materials
210 are fed to the filter press 232, is also connected
to the lower flange 76' of the washing vessel 7S, with
insertion of a valve 98'. The solids thus produced are
S fed for further use in the direction of the arrow 98' to
an appropriate installation (not shown), while the liquid
is fed via the line 234 in the direction of the arrow
234~ to the washing vessel 75.
The essential working steps are described below
by way of example by reference to the plant 50:
The so called loose material is fed from the
transport and conveyor belt 11 in the direction of the
arrows 11' and 12 to the washing vessel 10 and kept
therein in continuous motion by the associated ultrasonic
device 15. As a result of ~he cavitation effect achiev-
able by means of continuous motion of the loose material
and as a result of the chemical composition of the liquid
10', the dirt particles are detached from the loose
material and settle as sludge materials 10" at the bottom
of the vessel 10. ~he loose material cleaned in this way
is fed by the transport and conveyor belts 7, 6, 5 to the
vessel 4 and appropriately dried therein. The drying in
the vessel 4 is preferably effected by means of corres-
pondingly fed hot air. With the gate valve 2 open, the
dry and fairly free-flowing material passes for the
thermal regeneration into the piping system 40 inter-
actively connected to the distributor element 35.
~ s a result of the rotary motion, oriented about
the longitudinal axis X or X' or X' in the direction of
the arrow æ, of the piping system 4G arranged in the
combustion chamber 21' of the drum-type furnace 20, the
free-flowing material is transported by means of the
spiral-type pipes 41 in ~he direction of the arrow 20~.
As a result of using a pipe 41, which is wound in itself
in the longitudinal direction and, in profile cross-
section, is square, rectangular, triangular, polygonal or
else square with a parallel offset, the sand column in
the pipe is kept low, so that optimum heating of the
material is ensured.
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The material taken through the piping system 40
in free flow by the rotary motion of the piping system 40
is passed into the chamber 26 and subjected therein above
the grate 23 ~o the air stream of the fan 25, whereby the
residual gases and ~ines are ~iltered out of the sand.
The residual gases and fines are fed by the fan 25 via
the filter device 22 and via the return line 27 in the
direction of the arrow 27' to the combustion chamber 21'
for complete combustion as an additional energy carrier.
The cleaned material can be fed from the chamber
24 via a line 29 in the direction of the arrow 29' to the
vessel 30 as re-usable material, largely as new.
As distinct from the working steps described
above by reference to the plant 50 according to Figure 1,
corresponding fragment-type fractions are fed in the
plant 150 according to Figure 2 by the transport and
conveyor belt 111 in the direction of the arrows 111' and
112 to the rasping pot 110 mounted to be rotatable about
its vertical a~is Y in the direction of the arrow Y' and
are comminuted therein. The material collected in the
vessel 104 is then fed to the piping system 140 arranged
in the vessel 120.
The further working and process steps of the
plant lS0 are essentially identical to the working and
process steps described above in conjunction with the
plant 50 according to Figure 1.
