A UNIT FOR SEPARATING GLASS FROM MULTI-MATERIAL WASTE

TECHNICAL FIELD

This invention concerns the technical sector of plant for processing half-clear waste glass or mixed waste glass, derived from separately collected single- material waste or multi-material waste, for recycling purposes.

BACKGROUND ART

Half-clear waste glass derives in particular from residues from industrial production, while mixed waste glass comes from separately collected single materials, for example via kerb-side glass banks in urban areas, or multi-materials collection in skips for heterogeneous materials such as ferrous metals, non- magnetic materials (e.g. aluminium, tinplate) and plastic.

Plants for treating waste glass, or glass recovery plants, separate the glass from the other extraneous waste materials, such as organic matter, wood, cardboard, ferrous materials, aluminium, plastic and ceramics; the glass thus recovered (known as "furnace-ready waste glass"), which has a level of purity in compliance with the specifications set by law, is sent to glass factories for recycling, that is, to be used together with other raw materials to produce new glass containers.

A known type of plant for recovering glass from multi-materials waste uses a combination of manual labour and apparatus and/or devices to perform the following operations in sequence: loading the multi-materials with a mechanical shovel onto to a conveyor belt; manually sorting the multi-materials in order to eliminate large foreign bodies and excessive impurities such as to reduce their presence in subsequent processing phases; chopping and crushing the thus- sorted multi-materials into fragments of a smaller size, usually less than 4 - 5cm; processing the material using a device which uses a magnetic belt to remove magnetic bodies and wired glass; separating the materials using air blowers to remove light bodies such as paper, wood, etc., which are collected and extracted

by a cyclone; separating non-ferrous metallic bodies such as aluminium, lead, copper by means of a device (known as an LCS - Last Chance Separator) which exploits the principle of eddy currents; separating opaque bodies (e.g. ceramics) by means of a device (NIR - Near Infrared) comprising an optical detector of opaque bodies; and definitively sorting the material (quality control) manually to eliminate the small residues of ceramics, stone and metals which are still present despite previous selection operations.

Apparatus of these types for processing multi-materials have a wide range of drawbacks, such as for example: using significant manual labour to process and sort the multi-materials, in particular upstream of the plant (the above-mentioned manual sorting process); producing dust during the crushing and chopping process, which dust disperses and remains in suspension, thus polluting the environment and making it unhealthy for operators; the entire plant absorbs considerable amounts of energy, which can to a great extent be attributed to the crushing and chopping apparatus.

On account of their economic impact, all the above-mentioned drawbacks tend to convince bodies and organisations involved in this separating activity to direct their efforts towards separate single-materials collection for waste glass rather than towards multi-materials waste collection.

Plants for recovering glass from single-materials are gradually reaching technological levels which make it possible to progressively reduce the need for manual labour; however at present a manual inspection is still performed, both upstream of the optical reader so as to increase reliability and precision and thus limit the percentage of reject glass, and downstream of the optical reader (final quality control).

Note however than the separate collection of single-materials has the drawback of high management costs, since it requires appropriate glass banks for collecting the glass and specific motor vehicles provided with a mechanical arm to lift and empty the glass banks. Further, motor vehicles of this type are not provided with compactor devices, which are provided on multi-materials collection vehicles, so for a given volume of load compartment, their load capacity is certainly more limited.

DISCLOSURE OF INVENTION

The aim of the invention is to provide an innovatively-conceived unit for separating glass, which unit is destined to replace the manual sorting and crushing operations in known-type plants for separating glass from multi-materials, in order to obviate the drawbacks mentioned in connection with these types of materials in the preamble. A unit for separating glass is provided which can easily be integrated into similar plants of a known type.

A further aim of the invention consists in providing a unit for separating glass, which unit can be also be used in, and/or integrated into, plants for separating glass from single-materials.

A further aim of the invention consists in providing a unit for separating glass which is reliable, functional and the costs of which are relatively low in relation to the advantages provided.

A still further aim of the invention consists in providing a plant or system for separating glass from multi-materials comprising the above-mentioned unit for separating glass, the plant or system therefore being capable of obviating the drawbacks highlighted in the preamble in connection with knowη-type.

The above-mentioned aims are achieved in accordance with the contents of independent claim 1 and dependent claims 8 and 9.

In independent claim 1, a unit for separating glass from multi-materials is disclosed, characterised in that it comprises a rotary screen provided with a rotating perforated drum drawn in rotation by actuator organs, the rotating perforated drum comprising: a section at one end, for inputting the multi-materials comprising glass objects or fragments to be separated; a section at the opposite end, for expelling a part of the separated multi-materials; and a plurality of protuberances which are constrained to the inner surface of the rotating perforated drum, in order, during rotation, to intercept and retain portions of the multi-materials to be sorted and which are contained within the rotating perforated drum, until under gravity the portions fall and the relative breakable parts are

consequently shattered, the remaining part of the separated multi-materials then exiting through the relative through-holes of the rotating perforated drum. Specific embodiments of this unit are described in claims 2 to 7.

In accordance with dependent claim 8, a system is disclosed for separating glass from multi-materials, comprising the unit for separating glass of any one of claims 1 to 7, and a process line for a further operation of selection of the glass materials from the separated multi-materials, which line receives the separated multi- materials exiting through the through-holes of the rotating perforated drum and comprises conveyor organs and one, a part, or all of the selected elements of the following group, which are arranged in series in a predetermined order: means comprising blower organs for expelling the multi-materials below a certain weight threshold; means for expelling the magnetic materials from the multi-materials; means for expelling the non-magnetic materials from the multi-materials; and means for expelling the opaque materials from the multi-materials.

In accordance with dependent claim 9, a system is disclosed for separating glass from multi-materials, comprising the unit for separating glass of claim 6 or 7, and a plurality of process lines for performing subsequent operations to select the glass materials from the already separated multi-materials, which process lines receive the separated multi-materials, which have exited through the respective through- holes of the sectors of the rotating perforated drum, and which each comprise conveyor organs and none, one, a part, or all of the elements selected from the following group, which are arranged in series in a predetermined order: means comprising blower organs for expelling the multi-materials below a certain weight threshold; means for expelling the magnetic material from the multi-materials; means for expelling the non-magnetic materials from the multi-materials; and means for expelling the opaque materials from the multi-materials.

BRIEF DESCRIPTION OF THE DRAWINGS

Any characteristics of the invention which do not emerge from the foregoing will be better illustrated below, in accordance with the contents of the claims and with the assistance of the appended tables of the drawings, in which:

figure 1 shows a schematic side view of the unit for separating glass which is the object of the invention, in which the relative outer casing has been removed;

figure 2 is a schematic plan view of the separation unit of figure 1 ;

figures 3, 4 are respectively an axial section view and a transversal section view of the unit for separating glass of figure 1 , respectively in a reduced and an enlarged scale;

figure 5 shows a block diagram of a system for separating glass from multi-materials in accordance with a preferred embodiment, which uses the unit for separating glass from multi-materials which is the object of the invention and is specifically shown in figures 1-4;

figure 6, 7 show two block diagrams of the system for separating glass from multi-materials in accordance with constructional variants, which system uses the unit for separating glass from multi-materials which is the object of the invention and is shown in figures 1-4;

- figure 8 shows a block diagram of the system for separating glass from multi-materials in accordance with a further constructional variant, which system uses the unit for separating glass from multi-materials which is the object of the invention, in an embodiment thereof which is not shown.

BEST MODE FOR CARRYING OUT THE INVENTION

In figures 1-4, the reference number 1 indicates the unit for separating glass of the invention in its entirety, comprising a screen 2 consisting of a rotating perforated drum 3, which: is supported for example by two idle rollers which are constrained to the frame 4 of the unit 1 , which is closed laterally and superiorly by a casing 8, and which is drawn in rotation by actuator organs (not shown).

The rotating perforated drum 3 is inclined by a given angle to a horizontal reference; it exhibits an input section 11 at one end, and an output section 18 at the opposite end and at a lower height.

The rotating perforated drum 3 comprises, for example, three distinct cylindrical portions 15, 16, 17 which are arranged one after the other along the longitudinal axis of the rotating drum 3: the first cylindrical portion 15 is arranged at the input section 11 and exhibits a plurality of through-holes 30 of a size that permits the passage of objects or fragments of up to 15mm (the size of an object is considered as being the diameter of the sphere within which the object can be inscribed); the second cylindrical portion 16 and the third 17 cylindrical portion follow the first cylindrical portion 15 and are identical to each other, since they are provided with through-holes 30 of a size that permits passage of objects or fragments of up to 50mm in size.

In other words, in this case two distinct sectors of the rotating perforated drum 3 can be identified (although there can in general be one sector only, or even more than two), which differ from each other because of the dimensions of the relative through-holes 30; the first sector 150 coincides with the first cylindrical portion 15, while the second sector 160 coincides with the join between the second 16 and the third 17 cylindrical portion, both of which share the property of exhibiting through-holes 30 of the same size.

In general, a rotating perforated drum 3 exhibits a plurality of sectors (as in the example shown in the appended figures 1-4) which are ordered in a regular way along the longitudinal extension of the rotating perforated drum 3 on the basis of the size of the relative through-holes 30, such that the sector 150 which is adjacent to the input section 11 exhibits through-holes 30 having the smallest size among the holes provided and the sector 160 which is adjacent to the output section 18 exhibits through-holes 30 having the largest size among the holes provided.

Innovatively, the rotating perforated drum 3 exhibits a plurality of protuberances or prominences 12, 14 which are constrained to the relative inner surface 13, and which for example extend longitudinally and are angularly equidistant from one another (figure 4). The protuberances 12, 14 each comprise a support element 14 which is constrained to the inner surface 13 of the rotating perforated drum 3, and an end portion 12 which is constrained to the support element 14, and which for example can be constituted by a blade 12 oriented at right angles to the inner

surface 13.

The glass-separating unit 1 comprises, in addition: a feeder chute 20 which is connected to the input section 11 , onto which chute 20 the multi-materials to be separated are released (not shown in the figures) from a loading belt 19; and three manifolds, a first manifold 5, second manifold 6 and third manifold 7, which are arranged functionally below the rotating drum 3, in order to receive the multi- materials which are released respectively through the first 15, second 16 and third 17 cylindrical portions, and to convey the multi-materials onto two underlying conveyor belts, a first conveyor belt 21 and a second conveyor belt 22. In particular, the first conveyor belt 21 is destined to receive the fine particles (up to 15mm) which are released through the first manifold 5 by the first cylindrical portion or first sector 150, while the second conveyor belt 22 receives the large particles (between 15mm and 50mm) released through the second manifold 6 and third manifold 7 by the second cylindrical portion 16 and third cylindrical portion 17 respectively, the union of which portions defines, as mentioned above, the second sector 160.

There follows a description of the operation of the unit for separating glass of the invention.

As stated above, the conveyor belt 19 releases the multi-materials into the rotating drum 3 through the feeder chute 20.

The rotating drum 3 is drawn in rotation for example with continuous motion by the actuator organs; the blades 12 intercept and retain corresponding portions of multi-materials, which are thus drawn in rotation by the effect of activation of the drum 3, until under gravity they fall onto the inner surface 13, thus causing the breakable parts such as glass and ceramics to shatter. Advantageously, the blades 12 by their nature additionally constitute a breaker element for the breakable parts of the multi-materials which fall onto them; it is consequently possible to choose the number of blades 12 to be installed in the rotating perforated drum 3 on the basis of the required average size of the breakable parts.

The objects or fragments of multi-materials sized up to 15mm pass through the

corresponding through-holes 30 of the first sector 150 and are released through the first manifold 5 onto the first conveyor belt 21.

The objects or fragments of the multi-materials sized up to 50mm pass through the relative through-holes 30 of the second 16 and third 17 cylindrical portion (second sector 160) and are released respectively through the second manifold 6 or third manifold 7 onto the second conveyor belt 22. Most of the objects or particles of the multi-materials sized up to 15mm (fine particles) pass through the through-holes 30 of the first sector 150; consequently in practice the second sector 160 selects objects or particles of multi-materials which are sized between 15mm and 50mm (considered coarse particles).

The remaining part of the multi-materials travels along the entire length of the rotating perforated drum 30, and is released through the relative output section 18 onto a through-holes 25, which therefore receives the residue of the above- described separation process. The transit of the multi-materials inside the rotating drum 3, from the input section 11 towards the output section 18 is favoured by the rotating drum 3 being inclined by a predetermined angle relative to a horizontal plane.

The continuous movement of the multi-materials which are contained inside the rotating perforated drum 30 and their subsequent fall onto the inner walls 13 of the rotating perforated drum 30 or onto the blades 12 shatters the breakable parts, constituted prevalently by glass and ceramics; the higher degree of breakability of the glass, however, means that the glass materials shatter into a greater quantity of fragments.

Ceramic materials, on the other hand, on average give rise to coarser fragments (because ceramics have a lower degree of breakability than glass) and for this reason are partially discharged through the output section 18, while the remaining part, conveyed on the conveyor belt 22 for transporting the coarse particles, can be easily selected and eliminated in the subsequent separation phases (described below). In other words, an initial process of separating glass from ceramics takes place automatically already inside the rotating drum 3; this is extremely advantageous, since it makes it possible to obtain separated materials of a higher quality, that is to say, containing a smaller percentage of impurities.

The fine materials have a high degree of purity: they are constituted for the most part by glass with very low percentages of ceramics and can therefore be conveyed for example directly to the device (NIR) which separates out the ceramics fragments, without any further treatment phases.

The coarse materials can for example be conveyed towards known apparatus for separating the ferrous materials, non-magnetic materials (aluminium, lead, copper), lightweight materials (paper, wood) and opaque bodies (ceramics), as will be described below.

Separation of the glassy fragments on the basis of their size is particularly advantageous from various points of view: in the first place, fine materials can be conveyed directly to the detector of opaque bodies, not needing to undergo subsequent treatment operations: this also undoubtedly constitutes an advantage in terms of energy saving and of the scaling of the entire processing plant; secondly, this separation on the basis of the size of the particles (into fine and coarse particles) also enables more rational and effective scaling of the subsequent treatment apparatus, in particular of the device for detecting opaque bodies, which can operate in a much more reliable, efficient and precise way, releasing a smaller percentage of unwanted ceramics fragments at the output and, at the same time, rejecting a smaller quantity of glass fractions.

Advantageously, the rejected unbreakable waste (ferrous and non-magnetic materials, wood, paper and plastic) exiting from the rotating drum 3 remains whole and can therefore be recycled along a recovery line 40 which will be described below (figures 5-8); in known plants, all the material would be broken up and couid not be recovered. This also results in significant energy savings, since the unbreakable material does not undergo a wasteful crushing process.

Further, eliminating the breaking-up process means less dust is produced; in fact, the separation unit which is the object of the invention does not crush/grind the breakable parts but breaks them into fragments. This leads to reduced emission of dust into the surrounding environment and thus a healthier environment, with all the positive implications which this entails for all those who work there.

Advantageously, the unit for separating glass from multi-materials which is the

object of the invention leads to a significant energy-saving advantage: much less energy is required to make the rotating drum rotate than is required to drive the breaking-up apparatus.

A further advantage of the invention consists in having designed a unit for separating glass which requires no upstream manual sorting, which is necessary in known-type apparatus.

Further, the great effectiveness of the separation process implemented by the unit of the invention advantageously also allows glass which is highly contaminated with other types of material to be processed.

A still further advantage of this invention consists in having designed a unit for separating glass which can be usefully integrated into a plant for processing half- clear or mixed waste glass which can be obtained by separating not only multi- materials, but also single-materials which derive from separate waste collection, with all the positive implications thereby entailed.

The unit for separating glass which is the object of the invention brilliantly obviates all the drawbacks which are described in the preamble; further, the advantageous technical and functional characteristics inherent in the unit of the invention can bridge the gap which exists at the present time between separate single-materials collection of waste glass, which is presently preferred, and multi-materials waste collection. For a public authority or institution charged with rubbish collection and separation, the multi-materials collection option (even though, as specified above, the separation unit of the invention is also capable of processing single-materials) would deliver a significant reduction in terms of management costs, since collection containers would be constituted by dumpsters, while the motor vehicles for transportation would be normal compactor trucks.

A further advantage of the invention consists in having designed a unit for separating glass which is reliable, functional and the costs of which are relatively low compared with the advantages that are obtained.

In conclusion, note that the blades 12 can also be constituted by generic protuberances, which are shaped however in such a way as to retain the material

and thus to draw it in rotation until it falls and the relative breakable parts shatter against the inner surface 13 of the rotating drum 3; further, the protuberances can exhibit a limited length, less than the extension of the rotating drum 3, and can also be arranged at random on the inner surface 13 of the rotating drum 3.

The separation unit of the invention, described above with reference to a preferred embodiment, can be integrated into a system or plant for separating multi- materials, which system or plant will be described below with reference to the block diagrams shown in figures 5-8.

Figure 5 shows a preferred embodiment of the system for separating glass from multi-materials, which uses the unit for separating glass illustrated in figures 1-4, where it is indicated with reference number 1. In the figure only the reference numbers relative to the input section 11 , the output section 18, the first sector 150 and the second sector 160 are indicated.

The system comprises a recovery line 40 which receives the separated multi- materials exiting from the output section 18 of the rotating perforated drum 3 and comprises conveyor organs (not shown) and a plurality of apparatus arranged in series in a predetermined order, i.e.: an apparatus 41 comprising blower organs for expelling the multi-materials below a certain weight threshold (paper, wood, etc.); an apparatus 42 for expelling the magnetic materials from the multi- materials; an apparatus 43 for expelling the non-magnetic materials from the multi-materials.

The apparatus 41 , 42, 43 can also be arranged in a different order to that shown in figure 5. Their presence enables the separation and thus the recovery of lightweight materials, such as paper, wood, cardboard, magnetic and non- magnetic materials. Alternatively, it is possible to abstain from providing one or more of these apparatus.

In particular, the apparatus 41 can comprise a cyclone and a vibratory plate unit of known type (neither of which is shown) for separating the lightweight materials or else a vibratory plate unit of the type described in Italian patent application No. BO2008A000077.

The system also comprises a first process line 44 for a further operation of sorting the glass materials from the separated multi-materials, which process line 44 receives the separated multi-materials which have passed through the through- holes 30 of the first sector 150 of the rotating perforated drum 3 and comprises conveyor organs and a unit 47 (for example a hopper) for storing the multi- materials exiting from the first sector 150.

The system finally comprises a second process line 45 for a further operation of separating the glass materials from the separated multi-materials, which line 45 receives the separated multi-materials which have passed through the through- holes 30 of the second sector 160 of the rotating perforated drum 3 and comprises conveyor organs and the same apparatus which were described herein above arranged in series, indicated with reference numbers 41 , 42, 43 (also in this case the apparatus can be arranged in a different order from that shown in figure 5).

The presence of the apparatus 41, 42, 43 along the second process line 45 enables recovery of the lightweight materials, such as paper, wood, cardboard, magnetic materials and non-magnetic materials.

The first process line 44 joins the second process line 45 at the junction point T which is situated downstream of the apparatus 41 , 42, 43. An apparatus 46 of a known type is provided (mentioned also in the preamble, as were the apparatus 41 , 42, 43) downstream of the junction point T, for expelling the opaque materials from the multi-materials. Quality control can be arranged on the glass material thus selected (at present it is performed manually), downstream of the apparatus 46 and before the glass is stored and transported to the glass-making factory. This quality control is represented in figure 5 by a functional block 48.

During functioning of the glass separation system, the two process lines 44, 45 operate alternately: in a first operating configuration the unit for separating glass 1 is in operation and is separating the multi-materials, the second process line 45 is performing the subsequent operations of separating the glass from the separated multi-materials exiting from the second sector 160, and on the first process line 44 the multi-material exiting from the first sector 150 is being stored in the hopper 47; in a second operating configuration, the unit for separating glass 1 and the second process line 45 are at rest, while the hopper 47 is releasing the stored multi-

materials, which feed into the apparatus 46.

The apparatus 46 handles coarse multi-material particles (coming from the second process line 45) and fine multi-material particles (coming from the first process line 44) alternately; this is extremely advantageous, since it is possible to adjust the apparatus 46 for expelling opaque bodies on the basis of the system's operating configurations, as defined above, so that the apparatus 46 can treat fine particles (up to 15mm) or coarse particles (between 15mm and 50mm). Trials performed on this system for separating glass have revealed a significant improvement in the yield of this apparatus 46.

Figure 6 shows a variant of the system for separating glass which uses the unit for separating glass 1 shown in figures 1-4.

The system exhibits the same recovery line 40 which is shown in figure 5. The first process line 44 however comprises an apparatus 46 for expelling the opaque materials and the quality control 46; the second process line 45 comprises the apparatus 41 , 42, 43, 46 and the final quality control 48.

A further variant of the system, which is shown in figure 7, comprises: the second process line 45 comprising the apparatus 41 , 42, 43, 46; the first process line 44 comprising only the apparatus 46 for expelling the opaque materials from the multi-materials. The first process line 44 joins the second process line 45 at the junction point T which is arranged downstream from the apparatus 41 , 42, 43, 46; a quality control 48 is also provided downstream from the junction point T.

A still further variant of the system for separating glass is shown in figure 8. It uses a variant of the unit for separating glass 1 which is not shown in the appended figures. In particular, the rotating perforated drum 3 of the unit for separating glass 1 exhibits a single sector 150, and the through-holes 30 are, for example, all of the same size.

Once more the system comprises the recovery line 40 which is present in the other embodiments (which in any case is optional), and a single process line

(indicated with the reference number 45) for a further operation of selecting the glass materials from the separated multi-materials, which process line receives

the separated multi-materials exiting through the through-holes 30 of the first (and only) sector 150 of the rotating perforated drum 3, and comprises conveyor organs, the apparatus 41 , 42, 43, 46 and the quality control 48.

The system for separating glass using the unit for separating glass 1 described in the figures 5-8 brilliantly achieves the predetermined aims. Further, this system for separating glass can also handle single-materials.

The above description is a non-limiting example, therefore any practical/applicational variants are to be considered as being included within the protection ambit of the invention as described above and claimed below.