Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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1 It is well known that the solid city wastes contain
many materials, that everyday are thrown away, and that viceversa
could be used again in many other ways, also different from the
original ones.
It is in fact well known that in the said wastes are
present, for instance, notable amounts of paper coming out
from all the wrappings and packages of the consumption goods,
as also ferrous packages, as boxes, in which are preserved
foods and other materials, and furthermore organic elements,
as,. for instance, the kitchen wastes as vegetables, fruits,
bread, etc. Furthermore, in these city wastes are present in
a large amount plastics wastes comimg out in most cases, from
the plastics packaging and more in particular form the film.
used for.the delivery and the transport of the different goods
as also for the bags foreseen for the different discarded
materials.
It is also useful have in mind that in these wastes
is present also a noteworthy amount of glasses, especially
as bottles, in connection with the diffusion of the use of non-
20 returnable bottles. All these glasses with all the otheraforementioned goods, as also with other products, that are
present usually and/or exceptionally in the solid city wastes,
are worth of being recovered and used again.
In the past years were realized many different
installations for the recovery of the solid city wastes, but
these installations indeed had the purpose of using only the
organic elements in the city wastes for obtaining a product,
usually called "compost", being this material a kind of fertilizer,
at the same time a corrective of the soil.
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1 At present, however this technology is undoubtly
inadequate, as, a consequence of the demographic increase
as also for the changed tenor of life of the residents, in the
city wastes are present materials completely different from the
ones of the past, not only from a qualitative point of view,
but also as percent.
Indeed the presence of paper, plastic materials,
glasses and metals - more in particular iron - is increased
with a consequent reduction of the percent of the organic
10 materials.
Therefore it is evident that it is not more useful
employ the previous te~hnology as the installations of the
previous technology would meet big problems in connection
with the percents of the obtainable product in connection with
the amount of the materials to be rejected, or discharged
and also because the well known "compost" is now finding heavy
trade problems as consequence of the introduction on the markets
of new kinds of fertilizers.
It is therefore an object of the present invention an
20 installation, in which is possible pick-out automatically papers,
plastic materials, glasses, metals - more in particular iron -
organic materials, etc. r from the heterogeneous mass of the
wastes and in which the separated wastes can be sent to single
stations, where the raw selected materials are improved in such
a way to can be, in a second time, be transformed in new products
that are requested firmly and with increasing interest.
The installation of the present invention has sub-
stantially the purpose of linking together the working of different
machines in such a way to make easier the securing of products
30 of particular interest and, at the same time, with an unchanging
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1 and disadvantagefree working of the said machines.
The installation, according to the present invention
is set up on the automatic separating of the different components
of the wastes mass reaching in the selected materials also
the 85~ of the wished material.
Therefore, the installation is working following a
sequence of phases, that are carried out in stations that can
be deemed as satellite plants, where are carried out the
different operations of purification and transformation of the
different materials in such a way to allow their trade and
- eventually their preservation for the use in a second time.
The installation, according to the present invention,
works following a sequence of actions, that can be summarised
as follows:
1. Breakage of the containers of the solid city wastes,
i.e. in the majority of cases of the plastics bags
in which are collected the solid city wastes, to
obtain such wastes in bulk, in such a way to allow
the following working phases;
20 2. Rejection of the coarse materials, that are sent to
the dump or at the incineration plant;
3. Boards separation;
4. Separation of the paper mixed with plastics film;
5. Dry separation of plastics films from the paper;
6. Separation of the organic materials in their raw
state for subsequent use;
7. Use of the best portion of the organic materials
recovered in the phase ~ for the production of
stockfeed;
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1 8. Use of the remaining portion of the organic wastes,
obtained in the phase 6, after the removal of its
best elements according to the phase 7, for the
manufacture of dry-fertilizer;
9. Separation in all the phases of the treatment of
the iron materials for their subsequent use;
10. Separation of the glasses, preferably downstream
the phase 7, i.e. downstream the plant for the
production of the already quoted stockfeeding.
The attached drawing shows, using a block diagram,
the plant, according to the present invention, with its satellite
plants for the carrying out of the different working cycles.
With reference to the said drawing, the wastes, that
in a first moment are discharged in a dump 1 are drawn up by
a polyp and by an overhead travelling crane 2 and loaded on
feeding conveyors. On these conveyors the wastes are leveled
by a leveler 3 for metering the amount of the wastes, whereas,
of course, a convenient device 4 provides to the cutting and
the opening of the bags, in which are the wastes. A first
sieve 5 at the end of these conveyors allows the separation of
the more coarse parts. These more coarse parts are the ones
that are greater of a pre-established size and usually are
comprising great board boxes and/or bodies - as for instance
mattresses, chairs, prams, etc. - that cannot be regarded as
regular solid city wastes.
The said bodies of great sizes, that cannot be
recycled are sent to the discharge, or to the incineration
plant, whereas the boards, or similar materials, that are
rejected by the sieve 5, are sent to a machine 6, realized in
connection with the idea used in the design and realization
1 of the machine for the tearing of the bags, quoted as the one
used in the phase 4. On this machine, the board boxes are
broken, cut, torn, pulled away letting unchanged the materials -
usually metallic ones - that are within the said boxes. The
so treated material coming out from the machine 6 is sent,
through a conveyor to a separation electromagnet 9, that
provides to the recovery of the magnetic materials.
The non-magnetic material coming out from the separator
9 is fed to an oscillating feeder conveyor 10 feeding, at its
turn, an air classifier under vacuum, where air streams provide
to separate the most light materials, as for instance paper
elements, from the remaining material. These light elements
are carried in the decanter 11 of the machine and by a system
of conveyors to the press 13.
The material that was not removed by the air streams
in the air classifier 11, as too heavy, is fed to the incinera-
tion plant or to other installations for a subsequent treatment.
Coming back now to the material passed by the sieve 5,
the material is sieved a second time in the sieve 14, where the
said material is divided in two parts, i.e. in a finally
accepted part and a rejected one.
This material rejected by the sieve 14 is comprising,
in prominent amount, papers, plastics films, plastics materials
in other forms, hides, shoes and also some organic materials;
whereas, the accepted portion is comprising about exclusively
mould and organic materials.
Of course, the amounts of the different materials
obtained in these sieving operations is in connection with
the nature of the raw waste materials.
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1 At its turn, the materials that were rejected ~y the
sieve 14, are conveyed, through the conveyor 15, under an
electromagnetic separator 15, which is doing the same work of
the already quoted separator 9. The remaining material now free
of magnetic parts, and more in particular of iron, is conveyed
to the oscillating conveyor 17 feeding another air classifier 18.
This air classifier 18 divides the coming material in
a first portion comprising films and paper, that is fed to the
decanter 18 of the said machine, whereas the heavy, undergoes
the same destination of the one coming out the air classifier 11.
The material accepted by the classifier 18 comprises
substantially paper and plastics films and it is a very
interesting material, that must be subjected to subsequently
treatment for obtaining usable materials.
To this purpose however is needed, before all separate
the paper from the plastics films.
Such a separation is carried out in the station 19,
where a machine, comprising substantially a toothed rotor, that-
drawing advantage of the different elongation of the paper
and the plastics films, before their breaking - works in
such a way to break the paper, allowing the passage of the
plastics films in unchanged sizes through the machine. After
this passage through the machine of the station 19, it is still
present a material comprising paper and plastic films, however,
the paper has little sizes, whereas the plastics films have
still great sizes.
A sieve 20, eventually a rotating one, provides to
the separation of the two materials, accepting the paper and
rejecting the plastics materials.
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1 The rejected portion, comprising plastics materials
can be immediately baled in the station 21 and sold, or can
be fed to another section of the plant for its improvement
through washing processes, regeneration, etc.
At its turn, the accepted part of the material,
i.e. paper containng still some percent of plastics films,
is baled in the station 22 from which is sent to another plant
for being utilized for the production of paper pulp. Of course,
the aforementioned baling in the station 22 is only an inter-
mediate phase, not indispensable, for obtaining a long betweenthe waste working plant and the paper production plant.
Indeed, this paper comimg out from the station 22,
comprising still some extraneous materials and conveniently
baled, is sent through a feeder 23 to the hydropulper 24, where
with the usual addition of water is, as usual, let soak. Of
course, during this classic process, the real elements, are
dispersed and de-fibred, whereas the contaminating, i.e.
extraneous, materials remain unchanged, with consequent very
clear physical differences, easing the separation of these
last materials from the paper pulp.
Indeed, these extraneous bodies must be separated
from the paper pulp and such a separation must be a continuous
one as the feeding is continuous.
It must be now pointed out that the usual hydropulpers
are fitted with systems for the separation from the paper
materials of extraneous light bodies in low percents, but they
are not suitable for the treatment of the paper materials
recovered from the solid city wastes as these paper materials
are comprising a much higher percent of extraneous materials.
Therefore, the paper plant, according to the present invention,
is equipped with a separator with a rotating sieve, or any
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1 other suitable device which is connected with a usual hydro-
pulper, through a valve that it is opened and closed
periodically. This valve having the purpose of allowing the
periodical elimination from the pulping apparatus of the paper
pulp and of all the other materials, that cannot be pulped by
the water.
Therefore, the original paper material comprising
extraneous materials is sent in the practice to the afore-
mentioned selecting device, i.e. the rotating sieve in such a
10 way to separate the watery paper pulp from the other materials
as above quoted, that cannot be changed by the water action,
having specific weight very variable, as the sieve 25 is
working only in connection with the granulometry of the matter
and not in connection with its density or other characteristics.
As in the case of all other sieves already quoted in
this specification, the sieve 25 is rejecting as already stated,
a portion of the material, comprising the polluting extraneous
bodies, that can be sent to the incineration plant or to the
discharge, whereas is feeding the accepted liquid material
20 comprising the paper fibres, i.e. the paper pulp to a
collecting vat 26 from which is carried to the subsequent
phases of depuration and thickening - the thickneing phase is
carried out in a prethickener 27 and in a dehydrating press 28. t
Having in mind that the paper is recovered from city
wastes a very important treatment is the one subsequent the
press dehydration of the mass, i.e. the sanitary treatment of
the thickened pulp, that is carried out in a continuous
autoclave 29~ which is not under pressure, where the material
is kept at a sufficient high temperature, using steam, for
30 variable times, but always having a length of some tens of
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1 minutes, in such a way to grant the destruction of all the
dangerous germs and of the bacterial flora, that can be present
in the paper pulp.
Coming now back to the sieve 14, in which the accepted
material is comprising in prominent amount organic material in
connection with the way following which the material is
accepted it is differently recovered.
A particular employment is the use of all the
accepted material for the production of "compost" or dry
fertilizer. Whereas another possible employment is to feed the
accepted material to a separating sieve 30 in which the mould -
the accepted portion of the material - is sent to the incinera-
tion plant, or to the discharge, whereas the rejected portion,
that is the more coarse, but at the same time, the more noble
portion of this material can be used as stockfeed.
For obtaining the said stockfeed the rejected material
of the sieve 30 is subjected to a sequence of treatments, i.e.
a washing a decantation, a pressing, a steriliZation, a drying,
a depuration proceeds and at the end are subjected to pelletiz-
ing and to the packing. In other words the rejected organicmaterial coming from the sieve 30 are fed to a washing sieve 31
where the material is subjected to an effective and strong
wash for removing mould and inert elements, from this sieve 31
the material is carried to a suspension vat 32, where the
inert waste, the heavy ones, as glasses, stones, iron pieces
and different tailings, are falling on the bottom of the bat
rom which they are discharged, from time to time, through a
discharge mouth. From this decantation vat the light edible
materials, comprising nevertheless always some extraneous
materials, are carried out by two water streams, one ascensional
and the other horizontal in the impact direction with the
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1 water coming out from the recovery water of the overfall of the
decantation vat 32, in such a way to carry immediately to the
elements having a specific weight than the one of the water.
From the overfall of the vat 32, the water and the edible
materials are failing in the sieve 23, that has the purpose
of separating the water from the edible materials. The said
water is collected in tanks and recycled, whereas the material
is going to the press 34, having the purpose of further reducing
the amount of the water present in this treatment phase in the
tO edible materials" At the end of this preparatory cycle, the
organic material now deprived of the greatest portion of its
heavy inert materials and of the water is sent to a sterilizing
phase, in the sterilizers 35, that are autoclaves for a batch
treatment of the material, in which this last one remains for
the established time at the pre-established temperature.
Following this sterilization treatment, the product is dryed in
the dryer 36, in which the moisture of the product is reduced
at about 10% during this treatment, the size of all the
organic materials is reduced, whereas the inorganic materials
remain unchanged.
It is therefore possible, using another sieve 37 to
separate the organic materials from the tailings of
inorganic materials.
Indeed these polluting inorganic materials can be
present in two general forms, i.e. a heavy portion comprising
still glass, stones, that can be still present also in a very
little amount and a light portion, i.e. papers, plastics, etc.
that have reached a greater volume. Therefore the more light
portions are separated following one way and the heavy ones
following another system. More precisely the light portions
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1 are separated through a rotating and vibrating sieve 37 and are
sent to the incineration or to the discharge. At its turn, the
accepted portion of this sieve 37 comprising still the heavy
materials as little pieces of glass, or stones, that are
escaped to the hydraulic separation in the vat 32 are separated
through an air classification in the classifier 38, that allow
the separation of the light and heavy materials, i.e., the air
stream rising up removes the light portions comprising the
organic materials, whereas last fall the heavy portion that are
consequently discharged.
The so separated light portion is a stockfeed always
in a coarse form, that is subjected to a milling in the mill
39, through this milling is obtained the pulverization of the
said stockfeed, that is subsequently sent the stocking 40 and at
the end to the pelletizing press for its transformations in
pellets 41 as wished.
The iron portions collected by the different elec-
tromagnets are conveyed to a rotating furnace for the elimina-
tion of the polluting materials, that are comprising, as known,
labels, paints, tin, etc. In this furnace all the said pollut-
ing materials are destroyed and the resulting ashes are separated
from the iron material in the sieve 43. The iron material is
therefore sent to the press 44, that press this material in a
bale ready for the transport and the subsequent selling.
The plant, according to the present invention, was
of course, shown and described only by way of example, being
evident that the different treatment phases can be subject to
modifications, whether increasing or descreasing the same, in
connection with the material at disposal for the treatment,
having in mind that the solid city wastes have characteristics
that, usually, are different in the different areas, but that,
substantially are constant.
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