FIELD OF THE INVENTION

The invention relates to the technical sector concerning the separation of determined fractions from a liquid flow. In particular, the present invention relates to a separation apparatus for separating fractions of contaminant from a liquid flow comprising a heterogeneous mixture.

DESCRIPTION OF THE PRIOR ART

In recent years our planet has become gradually more aware of excessive consumption of the raw materials which are made available.

Further, these raw materials, once used in production or use cycles, and therefore at the end of their useful life, become a waste product, for example refuse, which can be managed either by being discarded or by a recycling treatment.

By managing this waste product by recycling treatment, it is possible to separate or salvage the raw materials.

For this reason, it is progressively more important to carry out a correct separate collection of waste products. Following this separate collection, methods and treatment apparatus for treatment of a waste product for separating recycling fractions comprising materials to be recycled are applied.

Document PCT/IB2018/055551 describes a treatment apparatus of a waste product for separating recycling fractions, comprising:

a separating column arranged substantially vertically, comprising: a cylindrical body provided on the lateral surface thereof with a plurality of holes and inferiorly with an opening for supply of a waste product to be treated, and a bladed shaft activated in rotation by a first motor and positioned coaxially internally of the cylindrical body;

a first upper discharge mouth arranged in the upper part of the cylindrical body for expelling a first recycling fraction present in the waste product subjected to the treatment, which first recycling fraction is separated and transported upwards by the bladed shaft;

a discharge group for extraction through the first upper discharge mouth and out of the cylindrical body of the above-mentioned first recycling fraction present in the waste product;

the discharge group comprising a discharge conduit connected to the first upper discharge mouth;

a second discharge mouth arranged in the lower part of the cylindrical body for evacuating a second recycling fraction.

The bladed shaft is inserted in the cylindrical body of the separating column and comprises a first rotor on the lateral surface of which a plurality of blades is fixed, orientated so as to define a discontinuous helical winding.

The bladed shaft further comprises, in proximity of the upper end, at least a plate fixed to the lateral surface of the first rotor and arranged radially.

The above-mentioned treatment apparatus of a waste product further comprises: a screw conveyor arranged coaxially internally of the discharge conduit and activated in rotation by a second motor for facilitating extraction of the first recycling fraction present in the waste product from the cylindrical body to the discharge conduit; a dilution unit positioned along the separating column for supplying water and like dilution liquids internally of the cylindrical body.

The discharge conduit, which is connected to the first upper discharge mouth, and the screw conveyor are arranged parallel to the tangential direction with respect to the cylindrical body, so as to facilitate conveying of the first recycling fraction present in the waste product from the cylindrical body to the discharge conduit.

The plate further comprises a bent edge at the relative free end, which bent edge is inclined so that when the first rotor is activated in rotation in a predetermined rotation activation direction, it is orientated according to the rotation activation direction so as to facilitate extraction of the first recycling fraction present in the waste product.

With reference to the separate collection of urban waste, in particular the separate collection of organic material, the final consumer differentiates the organic material, by separating and delivering the organic material in an appropriate packaging, producing a waste product which can be a packaging containing organic material. The packaging containing organic material can be treated by the above-mentioned treatment apparatus with the purpose of separating a first recycling fraction which can comprise fragments of packaging material and a second recycling fraction which can comprise fragments of organic material.

However, the second recycling fraction can also comprise fragments of packaging material, which do not reach the first discharge mouth during use of the above-described treatment apparatus, or stones or fragments of glass or heavy metals which are in the above-mentioned packaging containing organic material in a case where the separate collection has not been carried out correctly.

In other words, the second recycling fraction, given the heterogeneous goods composition thereof, defines a heterogeneous mixture comprising multiple fractions of contaminant (such as fragments of packaging material or stones or fragments of glass or heavy metals) in proportion to a main fraction (such as fragments of organic material).

In turn, the second recycling fraction has a high concentration of organic material and, for this reason, is generally subjected to a process of anaerobic digestion, with the aim of degrading the organic material to produce biogas, which is utilisable for the production of electricity.

The process of anaerobic digestion is progressively much more efficient when the presence of organic material is greater in the heterogeneous mixture subjected to the process.

Therefore, by subjecting the above-mentioned second recycling fraction to the process of anaerobic digestion, which comprises comprising multiple fractions of contaminant, a satisfactory production of biogas cannot be guaranteed and a quantity of sub-product, known as digested, in which those fractions of contaminant are present, will be produced.

Further, by subjecting the above-mentioned second recycling fraction to the process of anaerobic digestion, high management costs are involved in relation to the fact that the heavy fractions of contaminant, present internally thereof, tend to deposit on the bottom of the digester, leading to a reduction of the volume of the digester itself.

Consequently, in order to exploit the whole volume of the digester it will be apt to free the digester from the fractions of contaminant deposited on the bottom of the digester and this activity requires labour and costs.

Further, the light fractions of contaminant tend, on the other hand, to lie on the free surface of the second recycling fraction present internally of the anaerobic digester, causing an obstacle to the expansion of the biogas which is formed.

In this case too, with the aim of ensuring an adequate functioning of the anaerobic digester, it will be appropriate to free the digester from the fractions of contaminant lying on the free surface.

There arises, therefore, the need to subject the second recycling fraction to a further treatment process, for example a process of separation of the fractions of contaminant present internally thereof, with the aim of obtaining a product tending to a goods composition that is mostly homogeneous.

It is specified that the treatment apparatus, described in PCT/IB2018/055551 , can treat various waste products, not necessarily a packaging containing organic material.

Also in the case of waste products different to the packaging containing organic material, it has been verified that the second recycling fraction presents as a heterogeneous mixture, comprising fractions of contaminant which might be separated with the purpose of recovering them.

SUMMARY OF THE INVENTION

The aim of the present invention consists in obviating the above-mentioned drawbacks.

The above aim is attained by means of a separation apparatus for separating fractions of contaminant from a liquid flow comprising a heterogeneous mixture according to claim 1.

The separation apparatus of the present invention advantageously exploits the principle of settling and flotation in a liquid flow and thus enables the separation of fractions of contaminant comprised in a heterogeneous mixture.

Note that by settling is meant the process by which some particles suspended in a liquid flow, internally of a separation tank, deposit on the bottom by effect of gravitational force. By floating, on the other hand, is meant the process by which some particles suspended in a liquid flow, internally of a separation tank, tend to float on the free surface of the separation tank by effect of the lower specific weight thereof with respect to the liquid flow that they are placed in.

The liquid flow in inlet, during the flow along the first passage and the second passage in the first volume, will advantageously lose part of the flowing velocity thereof.

In other words, the liquid flow in inlet, while flowing along the first passage and the second passage, will lose a part of the velocity thereof, and will reach the second volume at a lower velocity with respect to the initial velocity.

Further, the liquid flow will reach the second volume, in which the separation of the first fraction of contaminant and the second fraction of contaminant will take place, at a velocity that is such as to enable the first plurality of motions and the second plurality of motions to push the heterogeneous mixture upwards and towards the half-way line and, thus, to cause the flotation of the first fraction of contaminant and the settling of the second fraction of contaminant.

The first plurality of motions, having an anti-clockwise direction, and the second plurality of motions, having a clockwise direction, make it so that the first fraction of contaminant reaches the free surface of the second volume of the separation tank.

Further, the second volume does not have, internally thereof, any obstacles to flotation and, therefore, to migration of the first fraction of contaminant towards the free surface of the second volume (in fact, the first internal lateral wall and the second internal lateral wall are present internally of the first volume).

Contemporaneously with the floating of the first fraction of contaminant, there is a facilitation of the settling of the second fraction of contaminant, i.e. the migration of the second fraction of contaminant towards the bottom of the separation tank.

Further, the first plurality of scrapers will intercept the first fraction of contaminant floating on the free surface of the second volume and will draw it towards the first plurality of scrapers which in turn draw the first fraction of contaminant towards the first outlet, preventing the relative mixing between the first fraction of contaminant and the liquid flow in inlet, as the first fraction of contaminant will be drawn against the current of the liquid flow in inlet along a path interposed between the first internal lateral wall and the second internal lateral wall.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention will be described in the following part of the present description, according to what is set down in the claims and with the aid of the accompanying tables of drawings, in which:

- figures 1-3 are respectively perspective, lateral and frontal views, of the separation apparatus of the present invention;

- figure 4 is a section view of figure 3 taken along section A-A;

- figures 5-7 are respectively perspective, lateral and frontal views of the apparatus of figures 1-3, in which some components have been removed better to evidence others;

- figure 8 is a section view of figure 6 along section B-B;

- figure 9 is a section view of figure 6 along section C-C. DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the appended tables of drawings, reference numeral (1) denotes a separation apparatus for separating fractions of contaminant (1a, 1b) from a liquid flow comprising a heterogeneous mixture (100).

The heterogeneous mixture (100) comprises: a first fraction of contaminant (1a) which can float and which comprises fragments of packaging material; and a second fraction of contaminant (1 b) which can settle.

The separation apparatus (1) comprises a separation tank (2) comprising in turn: a first external lateral wall (3) which comprises a first portion (4) and a second portion (5) consecutive to one another; a second external lateral wall (6) comprising a third portion (7) and a fourth portion (8) consecutive to one another and which is opposite the first external lateral wall (3); a bottom (9) conformed to collect the second fraction of contaminant (1b), comprising a fifth portion (91) and a sixth portion (92) consecutive to one another; a front wall (10); a rear wall (11); a first inlet (12) for a liquid flow comprising a heterogeneous mixture (100), which is arranged at the front wall (10); a second inlet (13) for the liquid flow, which is arranged at the front wall (10); a first outlet (14) for the first fraction of contaminant (1a), which is arranged at the front wall (10), between the first inlet (12) and the second inlet (13); a second outlet (15) for the second fraction of contaminant (1 b); a third outlet (16) for the liquid flow of which the heterogeneous mixture (100) has been cleared of the first fraction of contaminant (1a) and of the second fraction of contaminant (1 b) (see figures 1-3, 5 and 6).

The separation tank (2) further comprises:

a first internal lateral wall (17) which: originates at or in proximity of the front wall (10) and extends towards the rear wall (11); faces the first portion (4) of the first external lateral wall (3); is at a distance from the first external lateral wall (3) so that the first inlet (12) is interposed between the first external lateral wall (3) and the first internal lateral wall (17); forms, together with the first portion (4) of the first external lateral wall (3) a first passage (18) for the liquid flow coming from the first inlet (12); a second internal lateral wall (19) which: originates at or in proximity of the front wall (10) and extends towards the rear wall (11); faces the third portion (7) of the second external lateral wall (6); is at a distance from the second external lateral wall (6) so that the second inlet (13) is interposed between the second external lateral wall (6) and the second internal lateral wall (19); forms, together with the third portion (7) of the second external lateral wall (6), a second passage (20) for the liquid flow coming from the second inlet (13) (see figures 5 and 6).

Defined in the separation tank (2) are: a first volume (21) which is delimited by the front wall (10), by the first portion (4) of the first external lateral wall (3), by the third portion (7) of the second external lateral wall (6) and by the fifth portion (91) of the bottom (9) and which contains the first internal lateral wall (17) and the second internal lateral wall (19); a second volume (22) which is delimited by the second portion (5) of the first external lateral wall (3), by the fourth portion (8) of the second external lateral wall (6) and by the sixth portion (92) of the bottom (9) (see figure 6).

Further, the separation apparatus (1) comprises:

dispensing means of a fluid (23) which are arranged so as to dispense a fluid into the second volume (22) and to set off, during the use of the separation apparatus (1): a first plurality of motions (101) which push the heterogeneous mixture (100) upwards, to cause passage of the heterogeneous mixture (100) close to the second portion (5) of the first external lateral wall (3) of the separation tank (2) and towards the half-way line, occupying a first part of the second volume (22); and a second plurality of motions (102), which are directed opposite to the first plurality of motions (101) and which push the heterogeneous mixture (100) upwards, to cause passage of the heterogeneous mixture (100) close to the fourth portion (8) of the second external lateral wall (6) of the separation tank (2) and towards the half-way line, occupying a second part of the second volume (22), thus determining in the second volume (22) the floating of the first fraction of contaminant (1a) and the settling of the second fraction of contaminant (1b) (see figures 4-6 and 8- 9); a first plurality of scrapers (24) which are movable in the second volume (22) at the free surface of the liquid flow in order to draw the first fraction of contaminant (1a) towards the first volume (21) and which extend transversally between the second portion (5) of the first external lateral wall (3) and the fourth portion (8) of the second external lateral wall (6) (see figures 5 and 9); a second plurality of scrapers (25) which are movable in the first volume (21) at the free surface of the liquid flow in order to draw the first fraction of contaminant (1a) towards the first outlet (14) and which extend transversally between the first internal lateral wall (17) and the second internal lateral wall (19) (see figures 5 and 8);

pusher means (26) which act on the bottom (9) in order to move the second fraction of contaminant towards the second outlet (15) (see figures 5-8).

The third outlet (16) can be the outlet of the separation tank (2) for the liquid flow of which the heterogeneous mixture (100) has been cleared of the first fraction of contaminant (1a) and of the second fraction of contaminant (1b).

The second volume (22) can be delimited by the rear wall (11), by the second portion (5) of the first external lateral wall (3), by the fourth portion (8) of the second external lateral wall (6) and by the sixth portion (92) of the bottom (9) (see figure 6).

The first plurality of motions (101) can be a first plurality of annular motions (see figure 9).

The first plurality of motions (101) can be a first plurality of annular motions having an anti-clockwise direction.

The second plurality of motions (102) can be a second plurality of annular motions (see figure 9).

The second plurality of motions (102) can be a first plurality of annular motions having a clockwise direction.

The first plurality of motions (101) preferably push the heterogeneous mixture (100) upwards, to cause passage of the heterogeneous mixture (100) close to the second portion (5) of the first external lateral wall (3) of the separation tank (2) and towards the half-way line, occupying a first half of the second volume (22).

The second plurality of motions (102) preferably push the heterogeneous mixture (100) upwards, to cause passage of the heterogeneous mixture (100) close to the fourth portion (8) of the second lateral wall (6) of the separation tank (2) and towards the half-way line, occupying a second half of the second volume (22).

The liquid flow can be pumped into or from the separation tank (2) using a pump.

By liquid flow is meant the flowing of a liquid through a section of the separation tank (2).

By heterogeneous mixture (100) is meant a product comprising a plurality of fractions of different materials which make the goods composition of the product, as above-mentioned, heterogeneous.

By fractions of contaminant (1a, 1 b) is meant fractions of material which define the goods composition of the heterogeneous mixture (100).

The liquid flow can comprise water.

The first fraction of contaminant (1a) can comprise fragments of plastic packaging material and/or fragments of cardboard material for packaging and/or fragments of Tetrapak packaging material.

The second fraction of contaminant (1 b) can comprise stones and/or gravel and/or fragments of glass having a diameter of greater than 5 mm.

The liquid flow comprising the heterogeneous mixture (100), in inlet to the separation tank (2), can have a percentage of dry substance which varies from 6% to 15%.

By percentage of dry substance of the liquid flow is meant the percentage of residual heterogeneous mixture following the distancing of the liquid part in the liquid flow.

Should the liquid flow not have this percentage of dry substance, prior to the separation thereof by means of the separation apparatus (1) of the present invention, it is appropriate to dilute it with a further quantity of liquid, when the percentage of dry substance is greater than the above-indicated range values.

The first portion (4) and the second portion (5) can be adjacent to one another.

The third portion (7) and the fourth portion (8) can be adjacent to one another.

The first portion (4) and the third portion (7) can be arranged in proximity of the front wall (10) (see figure 6).

The second portion (5) and the fourth portion (8) can be arranged in proximity of the rear wall (11) (see figure 6).

The second outlet (15) is preferably arranged at the rear wall (11).

The second outlet (15) can be arranged at the bottom (9) of the separation tank (2).

The third outlet (16) is preferably arranged at the rear wall (11).

The dispensing means of a fluid (23) can be dispensing means of air or water.

The dispensing means of a fluid (23) can be arranged at the bottom (9).

The dispensing means of a fluid (23) can be arranged at a join zone between the first external lateral wall (3) and the bottom (9) and the join zone between the second external lateral wall (6) and the bottom (9) (see figures 6-9).

The dispensing means of a fluid (23) can be arranged in the first volume (21) and at the first passage (18) to mix the liquid flow when it flows in the first passage (18) and at the second passage (20) to mix the liquid flow when it flows in the second passage (20).

Each scraper (24a) of the first plurality of scrapers (24) extends along the width of the separation tank (2) in order to draw the first fraction of contaminant (1a) which, when floating in the second volume (22), is arranged in proximity of the first external lateral wall (3) and the second external lateral wall (6) (see figures 4, 5 and 9).

Each scraper (25a) of the second plurality of scrapers (25) can have an extension in width that is smaller than the extension in width of each scraper (24a) of the first plurality of scrapers (24) (see figures 5 and 8).

The scrapers (24a) of the first plurality of scrapers (24) can advantageously also intercept the first fraction of contaminant (1a) which is floating in proximity of the first external lateral wall (3) and the second external lateral wall (6).

The scrapers (25a) of the second plurality of scrapers (25) advantageously enable the migration of the first fraction of contaminant (1a) towards the first outlet (14), limiting the relative mixing thereof with the liquid flow in inlet in the first passage (18) and the second passage (20), as the scrapers (25a) of the second plurality of scrapers (25) are arranged in such a way as to be interposed between the first internal lateral wall (17) and the second internal lateral wall (19).

The bottom (9) of the separation tank (2) preferably comprises: a first bottom wall (9a); a second bottom wall (9b) which is connected to the first bottom wall (9a) and which is inclined with respect thereto so that the second fraction of contaminant (1b), during the relative settling, slides along the second bottom wall (9b) and towards the first bottom wall (9a) and a third bottom wall (9c), which is connected to the first bottom wall (9a), which is opposite the second bottom wall (9b) and which is inclined with respect to the first bottom wall (9a) so that the second fraction of contaminant (1b), during the relative settling, slides along the third bottom wall (9c) and towards the first bottom wall (9a) (see figures 5 and 7-9).

The bottom (9) of the separation tank (2) can have a truncoconical shape.

The fifth portion (91) of the bottom (9) can comprise a part of the first bottom wall (9a), a part of the second bottom wall (9b) and a part of the third bottom wall (9c).

The sixth portion (92) of the bottom (9) can comprise a part of the first bottom wall (9a), a part of the second bottom wall (9b) and a part of the third bottom wall (9c).

The pusher means (26) can act on the first bottom wall (9a). During the relative settling of the second fraction of contaminant (1b), the second bottom wall (9b) and the third bottom wall (9c) advantageously ensure conveying the second fraction of contaminant (1b) to the first bottom wall (9a) on which the pusher means (26) act.

The separation apparatus (1) of the present invention can be used for flow rate values of the liquid flow comprised between 5 m ³ /h and 40m ³ /h.

The first internal lateral wall (17) is preferably distanced from the bottom (9) so that the second fraction of contaminant (1b), which settles while the liquid flow in inlet crosses the first passage (18), can slide along the second bottom wall (9b) and towards the first bottom wall (9a); the second internal lateral wall (19) is distanced from the bottom (9) so that the second fraction of contaminant (1b), which settles while the liquid flow in inlet crosses the second passage (20), can slide along the third bottom wall (9c) and towards the first bottom wall (9a).

Should the heterogeneous mixture (100) comprise a second fraction of contaminant (1 b) with settling times that are such as to determine the relative settling in the first volume (21), the second fraction of contaminant (1b) can advantageously slide towards the first bottom wall (9a) and be moved towards the second outlet (15) without remaining in the first passage (18) and/or in the second passage (20).

The first internal lateral wall (17) can be arranged at a distance from the bottom (9) that varies from 500 mm to 800 mm.

Likewise, the second internal lateral wall (19) can be arranged at a distance from the bottom (9) that varies from 500 mm to 800 mm.

The first external lateral wall (3) comprises: a first part of upper end (27) which extends superiorly of the first portion (4); a second part of upper end (28) which extends superiorly of the second portion (5) (see figures 7-9).

The second external lateral wall (6) can comprise: a third part of upper end

(29) which extends superiorly of the third portion (7); a fourth part of upper end

(30) which extends superiorly of the fourth portion (8) (see figures 7-9). The first plurality of scrapers (24) is fixed to the second part of upper end (28) and to the fourth part of upper end (30) and the second plurality of scrapers (25) is fixed to the first part of upper end (27) and to the third part of upper end (29) (see figures 5 and 6).

The second part of upper end (28) and the fourth part of upper end (30) can be removably fixed to the second portion (5) and to the fourth portion (8) so that the second part of upper end (28) and the fourth part of upper end (30) can be removed from the separation tank (2) in order to intervene with the maintenance operations of each scraper (24a) of the first plurality of scrapers (24) (see figures 7-9).

The first part of upper end (27) and the third part of upper end (29) can be removably fixed to the first portion (4) and to the third portion (7) so that the first part of upper end (27) and the third part of upper end (29) can be removed from the separation tank (2) in order to intervene with the maintenance operations of each scraper (25a) of the second plurality of scrapers (25).

Should it be necessary to intervene with maintenance operations on the components making up the scrapers (24, 25a) of the first plurality of scrapers (24) and of the second plurality of scrapers (25), it will advantageously not be necessary to interrupt the functioning process of the separation apparatus (1) and, therefore, completely empty the separation tank (2) in order to intervene on the scrapers (24a, 25a) from inside the separation tank (2).

In detail, the first part of upper end (27) and the third part of upper end (29) bear the second plurality of scrapers (25), the relative movement chain and the relative activating motor of the movement and are fixed by screws and bolts respectively to the first portion (4) and the third portion (7).

In a case where it is necessary to intervene on a scraper (25a) of the second plurality of scrapers (25), it is possible to separate the first part of upper end (27) and the third part of upper end (29) respective from the first portion (4) and to the third portion (7) and intervene on the scraper (25a) of the second plurality of scrapers (25), once separated from the separation tank (2). Like considerations are valid also for the second part of upper end (28) and the fourth part of upper end (30) in relation to each scraper (24a) of the first plurality of scrapers (24).

In detail, the second part of upper end (28) and the fourth part of upper end (30) bear the first plurality of scrapers (24), the relative movement chain and the relative activating motor of the movement and are fixed by screws and bolts respectively to the second portion (5) and the fourth portion (8).

The first part of upper end (27) can be adjacent to the first portion (4).

The second part of upper end (28) can be adjacent to the second portion (5).

The first portion (4) can be interposed between the bottom (9) and the first part of upper end (27).

The second portion (5) can be interposed between the bottom (9) and the second part of upper end (28).

The third part of upper end (29) can be adjacent to the third portion (7).

The fourth part of upper end (30) can be adjacent to the fourth portion (8).

The third portion (7) can be interposed between the bottom (9) and the third part of upper end (29).

The fourth portion (8) can be interposed between the bottom (9) and the fourth part of upper end (30).

The first part of upper end (27) and the third part of upper end (29) can bear the scrapers of the second plurality of scrapers (25).

The second part of upper end (28) and the fourth part of upper end (30) can each bear a scraper (24a) of the first plurality of scrapers (24).

The dispensing means of a fluid (23) preferably comprise a first plurality of nozzles for air injection (31) which are arranged at the bottom (9) of the separation tank (2) and which are orientated upwards.

The first plurality of nozzles for air injection (31) advantageously inject air into the second volume (22) to push the heterogeneous mixture (100) upwards. Further, the first plurality of nozzles for air injection (31) advantageously inject air into the first volume (21) to mix the liquid flow in the first passage (18) and second passage (20).

The first plurality of nozzles for air injection (31) can inject air into the second volume (22) in order to set off, during the use of the separation apparatus (1): a first plurality of motions which push the heterogeneous mixture (100) upwards, to cause passage of the heterogeneous mixture (100) close to the second portion (5) of the first external lateral wall (3) of the separation tank (2) and towards the half-way line and a second plurality of motions which push the heterogeneous mixture (100) upwards, to cause passage of the heterogeneous mixture (100) close to the fourth portion (8) of the second external lateral wall (6) of the separation tank (2) and towards the half-way line, thus determining in the second volume (22) the floating of the first fraction of contaminant (1a) and the settling of the second fraction of contaminant (1b).

A first part of nozzles (31a) of the first plurality of nozzles for air injection (31) can be arranged at the bottom (9) in the first volume (21).

A second part of nozzles (31b) of the first plurality of nozzles for air injection (31) can be arranged at the bottom (9) in the second volume (22).

A third part of nozzles (31c) of the first plurality of nozzles for air injection (31) can be arranged at the bottom (9) in the second volume (22), downstream of the second part of nozzles (31 b).

The first part of nozzles (31a) of the first plurality of nozzles for air injection (31) can inject an air flow rate that is greater than the air flow rate injected by the second part of nozzles (31 b) of the first plurality of nozzles for air injection (31).

The second part of nozzles (31 b) of the first plurality of nozzles for air injection (31) can inject an air flow rate that is greater than the air flow rate injected by the third part of nozzles (31c) of the first plurality of nozzles for air injection (31). In other words, the first part of nozzles (31a), the second part of nozzles (31 b) and the third part of nozzles (31c) can inject an air flow rate with a value that decreases starting with the first outlet (14) towards the third outlet (16).

By reducing the air flow rate injected by the first plurality of nozzles for air injection (31) in proximity of the third outlet (16), it is ensured that the second fraction of contaminant (1b) remains at the bottom (9) and that it is conveyed to the second outlet (15) by the pusher means (26) without newly dispersing in the liquid flow.

The dispensing means of a fluid (23) preferably comprise a first plurality of nozzles for spraying a liquid (32) which are arranged superiorly of the separation tank (2) so as to spray the free surface of the liquid flow in the second volume (22), during the use of the separation apparatus (1), and which are orientated so as to push the first fraction of contaminant (1a) towards the scrapers of the second plurality of scrapers (25) (see figure 5).

The nozzles of the first plurality of nozzles for spraying a liquid (32) advantageously sprinkle the free surface with a liquid in order to draw the first fraction of contaminant (1a) towards the first outlet (14).

The first plurality of nozzles for spraying a liquid (32) can be fixed to the second part of upper end (28) and to the fourth part of upper end (30).

The nozzles of the first plurality of nozzles for spraying a liquid (32) can have a “direct” liquid jet.

The dispensing means of a fluid (23) can further comprise a second plurality of nozzles for spraying a liquid (33) which is arranged superiorly of the separation tank (2) and can have a“sprinkler” liquid jet to reduce the volume of the foam that is created on the free surface of the separation tank (2), during the use of the separation apparatus (1) (see figures 7-9).

Further, the second plurality of nozzles for spraying a liquid (33) dampens the first fraction of contaminant (1a) floating on the free surface, which, in contact with air, might solidify. In detail, the separation tank (2) can comprise covers (34) which can be fixed to the first part of upper end (27) and to the second part of upper end (28), to the third part of upper end (29) and to the fourth part of upper end (30) and at which the second plurality of nozzles for spraying a liquid (33) is arranged.

The liquid of the first plurality of nozzles for spraying a liquid (32) and the second plurality of nozzles for spraying a liquid (33) can be water.

The separation apparatus (1) preferably comprises an outlet conduit (35) arranged at the first outlet (14), which outlet conduit (35) in turn comprises a ramp (36) which is arranged internally of the separation tank (2) and which is inclined towards the bottom (9) of the separation tank (2); the ramp (36) of the outlet conduit (35) being arranged so that a scraper (25a) of the second plurality of scrapers (25), by drawing the first fraction of contaminant (1a) towards the first outlet (14), abuts the ramp (36) when it reaches in proximity of the first outlet (14) in order to facilitate the exit of the first fraction of contaminant (1a) towards the first outlet (14).

The outlet conduit (35) can comprise a slide (37) which is arranged in such a way as to be opposite the ramp (36).

The combined action of the ramp (36) and the scraper (25a) of the second plurality of scrapers (25), which is drawing the first fraction of contaminant (1a) towards the first outlet (14), advantageously ensures the complete removal, via the first outlet (14) of the first fraction of contaminant (1a) which is being drawn, as the ramp (36) functions as a rest base for the scraper (25a).

The third outlet (16) is preferably arranged at the rear wall and the separation apparatus (1) comprises a first barrier (38) which is arranged transversally to the separation tank (2) and which is in proximity of the free surface of the liquid flow and of the third outlet (16) and which is distanced from the bottom (9) so as to prevent the first fraction of contaminant (1a), which is floating in the second volume (22), from being drawn by the liquid flow, of which the heterogeneous mixture (100) has been cleared of the fractions of contaminant (1a, 1 b), which migrates from the second volume (22) towards the third outlet (16). The first barrier (38) advantageously prevents the floating first fraction of contaminant (1a) from reaching the third outlet (16).

The first barrier (38) can be at a distance from the bottom (9) that is comprised between 500 mm and 800 mm.

The pusher means (26) preferably comprise a screw conveyor (39) which extends along the first bottom wall (9a) in order to advance the second fraction of contaminant (1 b) towards the second outlet (15).

The second outlet (15) is preferably arranged at the rear wall (11) and the separation apparatus (1) comprises a second barrier (40) which is arranged transversally to the separation tank (2) and which is in proximity of the bottom (9) and of the second outlet (15) so that the second fraction of contaminant (1b), which is settled in the second volume (22), can be prevented from being drawn by the liquid flow, of which the heterogeneous mixture (100) has been cleared of the fractions of contaminant, which migrates from the second volume (22) towards the third outlet (16) (see figures 4-5).

The second barrier (40) advantageously prevents the settled second fraction of contaminant (1 b) from reaching the third outlet (16).

Further, the second barrier (40) ensures that part of the second fraction of contaminant (1 b), which is dispersed in the liquid flow in proximity of the pusher means (26), remains in proximity of the pusher means (26) on reaching the second outlet (15).

Consequently, the second barrier (40) prevents the liquid flow, in which the heterogeneous mixture (100) has been cleared of the fractions of contaminant (1a, 1b), which is migrating from the second volume (22) towards the third outlet (16), when in proximity of the third outlet (16), from dragging with it the second fraction of contaminant (1b).

The second barrier (40) can be arranged opposite with respect to the bottom (9), with an orientation inclined towards the second outlet (15).

The second barrier (40) can comprise a portion of end (41) which is translatable along the length of the second barrier (40) in order to move towards or away from the first barrier (38), with the purpose of reducing or increasing the passage gap for the liquid flow, the heterogeneous mixture (100) of which has been cleared of the fractions of contaminant (1a, 1 b), towards the third outlet (16).

This translation of the portion of end (41) of the second barrier (40) varies according to the characteristics of the liquid flow in inlet to the separation apparatus (1).

By way of example, in a case where the heterogeneous mixture (100) derives from crushing and separation of packages containing organic material in arrival from urban waste collection, then the first fraction of contaminant (1a) can comprise fragments of plastic packaging material and/or fragments of Tetrapak packaging material; while the second fraction of contaminant (1b) can comprise stones and/or fragments of glass and/or fragments of metals.

In a case where the heterogeneous mixture (100) derives from crushing and separation of plastic and/or cardboard packaging of expired ice cream, then the first fraction of contaminant (1a) can comprise fragments of plastic packaging material and/or fragments of cardboard packaging material.

In a case where the heterogeneous mixture (100) derives from crushing and separation of packages containing tin or aluminium cans containing expired soft drinks, the second fraction of contaminant (1b) can comprise fragments of tin or aluminium.

Lastly, in a case where the heterogeneous mixture (100) derives from a paper production process, then the first fraction of contaminant (1a) can comprise fragments of plastic packaging material and/or fragments of aluminium packaging material and the second fraction of contaminant (1 b) can comprise stones and/or fragments of glass and/or fragments of metals. The following contains an illustration of the functioning of the separation apparatus (1) of the present invention.

The liquid flow comprising the heterogeneous mixture (100) is supplied via the first inlet (12) and the second inlet (13) into the separation tank (2) then to cross the first passage (18) and the second passage (20) in the first volume (21) and in order, successively, to reach the second volume (22). On activating the first plurality of nozzles for air injection (31), the first plurality of motions (101) and the second plurality of motions (102) will be set off internally of the second volume (22) and will determine the floating of the first fraction of contaminant (1a). At the same time, the first plurality of motions (101) and the second plurality of motions (102) will cause the settling of the second fraction of contaminant (1b), which will be conveyed to the first bottom wall (9a), from the second bottom wall (9b) and from the third bottom wall (9c).

The second fraction of contaminant (1b), once having reached the first bottom wall (9a), when sliding along the second bottom wall (9b) and towards the third bottom wall (9c), will be conveyed towards the second outlet (15) by the activation of the screw conveyor (39).

The first fraction of contaminant (1a), floating on the free surface of the second volume (22), will be drawn by the scrapers of the first plurality of scrapers (24), and pushed by the first plurality of nozzles for spraying a liquid (32) towards the scrapers of the second plurality of scrapers (25).

Each scraper (25a) of the second plurality of scrapers (25) will draw the first fraction of contaminant (1a) up to in proximity of the first outlet (14) in order to abut the ramp (36). At this point, the first fraction of contaminant (1a), in proximity of the first outlet (14), will inferiorly contact the ramp (36) which will convey it, together with the scraper (25a) of the second plurality of scrapers (25) towards the first outlet (14).

The liquid flow the heterogeneous mixture (100) of which has been cleared of the first fraction of contaminant (1a) and of the second fraction of contaminant (1b), will follow the flow direction of the liquid flow in inlet and will reach the third outlet (16).