WO1998045057A1

WO1998045057A1 - Process for separating non-ferrous articles, and a non-ferrous article adapted to be separated

Info

Publication number: WO1998045057A1
Application number: PCT/EP1998/001776
Authority: WO
Inventors: William Rossi
Original assignee: William Rossi
Priority date: 1997-04-04
Filing date: 1998-03-19
Publication date: 1998-10-15
Also published as: IT1290454B1; AU7210998A; ITMI970780A1

Abstract

This process is effective to suitably separate one article from other articles, regardless of the physical, chemical and geometrical features of the various articles. In particular, the process allows non-ferrous articles of one kind to be separated from non-ferrous articles of different kinds by the application to the former of predetermined ferromagnetic markers. In this way, different magnetic properties can be imparted to different non-ferrous articles, so that articles of different kind can be distinguished magnetically. More particularly, in the instance of plastic bottles for recycling, the ferromagnetic markers may include hoops applied near the bottle cap, or tags applied to the bottle bottom, or metal bands glued to the bottle label.

Description

Process for separating non-ferrous articles, and a non- ferrous article adapted to be separated

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DESCRIPTION This invention relates to a process for separating non- ferrous articles of one kind from non-ferrous articles of other different kinds, and to a non-ferrous article suitably adapted to be separated from non-ferrous articles of different kinds.

Especially in the field of waste disposal, there exists a growing demand for suitable facilities to separate certain articles, having given chemio-physical characteristics, from other articles with different characteristics. With regard to recycling, there is the need not only to separate articles of a given kind from articles of different kinds, but also to separate an article from other articles which, while belonging to the same basic kind, are differentiated by some specific physical, chemical, or geometrical features. A typical example is that of plastic bottles. Plastic bottles must be separated from other waste matter or other kinds of bottles, and it is advisable to have bottles made of plastics of one kind separated from those made of some other kinds of plastics.

It is known the use of essentially mechanical and chemical separation processes to separate a given article from other articles .

In the mechanical processes, the separation is effected by mechanisms which operate on the basis of a difference in weight or shape between the article to be separated and the others (in the former case, the articles may be ground and then separated by gravity or insufflation of compressed air; in the latter, the articles are separated manually or using optical detectors to detect the characteristics of the specific fraction to be separated) . However, while the gravity processes can only separate materials having markedly different specific densities, the shape-detecting processes have difficulty to recognize objects which may be fed to the process in random orientations, or which may have different wear or physical conditions. Neither processes are fully satisfactory in separating articles which belong to the same general kind, such as plastic bottles and as may be required by recycling in order to save energy and protect the environment .

Separation by chemical processes involves the use of solvents to separate polymeric molecules in a dissolved or gaseous state. Such processes, while meeting the requirement for separation of articles which belong to the same general kind, such as plastic bottles, have a problem in that they are cost-inefficient and utilize toxic substances.

The underlying technical problem of this invention is to arrange for an article to be easily separated from other articles regardless of the physical, chemical and geometrical features of the various articles.

According to a first aspect, this invention relates to a process for separating non-ferrous articles of one kind from non-ferrous articles of other different kinds, characterized in applying to the non-ferrous articles of said one kind a ferromagnetic marker effective to make them magnetically distinguishable from the articles of other different kinds.

By this process, any one article can be separated from other non-ferrous articles by utilizing the magnetic properties conferred to the one article by the ferromagnetic marker applied on it.

In particular, where the non-ferrous articles comprise plastic bottles for recycling, the various kinds of plastic bottles to be separated can be distinguished from one another by applying distinctive ferromagnetic markers on them.

The ferromagnetic markers may be of different types. Advantageously, they may be tags applied to the bottle bottoms, hoops encircling the bottles near their caps, or a substantially complete ring of embedded or stuck tags extending substantially around a circumference near to the bottle necks.

In this way, the different kinds of plastic bottles can be separated even when they are fed to the separating station in a crushed state. By being bonded directly to the bottles, these markers will stay securely therewith, even after the bottles have been crushed.

Advantageously, the ferromagnetic markers may be applied to labels on the bottles.

This would make bonding the ferromagnetic markers directly to the bottles unnecessary, thereby simplifying the marker application and removal operations, as well as the bottle manufacturing process.

Advantageously, the ferromagnetic markers are disposed on the labels so as to substantially encircle the bottles after the labels are applied.

This particular disposition of the markers on the labels makes the markers accessible regardless of the orientations of the bottles, thereby facilitating the subsequent separating operation.

Advantageously in this invention, the separation of non- ferrous articles of one kind from non-ferrous articles of other kinds comprises the following steps: discharging the articles bearing different ferromagnetic markers on a collecting path; moving an electromagnet adjacently to the collecting path so as to attract all the different articles bearing ferromagnetic markers; progressively shifting the electromagnet along a plurality of paths and decreasing in steps the amplitude of the current flowing through the electromagnet to cause the electromagnet to release articles of a predetermined kind onto each collecting surface; collecting, at a plurality of collecting zones, the articles released by the electromagnet on each path; removing the ferromagnetic markers from the collected articles .

Thus, the separation process is reduced to a sequence of simple and inexpensive operations requiring no devices or equipment of any complexity. In addition, the process is quite versatile and, hence, adapted to separate articles of various kinds .

Advantageously, the collecting path and the plurality of paths comprise a plurality of belt conveyors, all driven in the same direction, and the plurality of collecting zones comprise a plurality of collecting receptacles, each located at one end of each conveyor for collecting the articles being progressively released by the electromagnet onto the belt conveyors, and removing the ferromagnetic markers from the collected articles.

This allows the article separation and marker removal process to be automated and optimized, thereby to afford a higher amount of separated articles and drastically reduced costs .

Advantageously, the electromagnet can be moved above the belt conveyors along a perpendicular direction to the running direction of the belt conveyors.

This also affords significant time savings, additionally to the possibility of expanding the line to include further electromagnets in parallel, where its capacity to process articles for separation is to be increased.

According to a second aspect, the invention relates to a non-ferrous article, specifically a plastic bottle, suitably adapted for separation from articles of different kinds, which is characterized in that it incorporates a ferromagnetic marker.

The ferromagnetic marker may be of various types. Advantageously, it can be applied to a bottle label and disposed to substantially encircle the bottle once the label is applied; alternatively, it may be a tag applied to the bottle bottom, or a hoop applied to the bottle near its cap, or a ring of embedded or stuck tags extending substantially around a circumference near the bottle neck.

Further features and advantages of a process and article according to this invention will be more clearly apparent from the following description of a preferred embodiment, given with reference to the accompanying drawings. In the drawings :

Figure 1 shows three non-ferrous articles according to the invention;

Figures 2 to 6 illustrate schematically the successive steps of separating the articles shown in Figure 1; and

Figures 7 to 9 shows other three types of ferromagnetic markers disposed on bottles being delivered to the separating steps of Figures 2 to 6 in an expected crushed state.

Referring to the drawing views, respectively shown at la, lb and lc are three different non-ferrous articles, in particular three different kinds of plastic bottles for recycling. As shown in Figure 1, a label 2a of the bottle la has a predetermined type of ferromagnetic marker 3a, in particular a magnetic band, attached thereto. A label 2b of the bottle lb bears a different type of marker 3b. The bottle lc bears no ferromagnetic marker. Thus, the bottles la, lb and lc are magnetically distinguishable from one another, i.e. differently responsive to the same magnetic field. The markers 3a and 3b are located on the labels 2a and 2b such that, when the labels are applied to the bottles la and lb, the markers 3a and 3b will extend all around the circumferences of their respective bottles.

Figure 2 shows a collecting path 4 for the different kinds of bottles la, lb and lc, which includes a transport means 8 adapted to arrange the different kinds of bottles so as to make the subsequent separating step easier. An electromagnet 5 capable of attracting bottles of the kinds la and lb which bear the ferromagnetic markers 3a and 3b is provided above the collecting path 4. A plurality of paths, specifically a first path 6b and a second path 6a as shown in Figure 3, to which the electromagnet 5 will release each time a predetermined kind of bottle, and a plurality of collecting zones, specifically a first collecting zone 7b and a second collecting zone 7a, which comprise a means 10 for removing the labels 2b and 2a from the bottles of the kinds lb and la are provided beneath the electromagnet 5. In a specially advantageous embodiment, shown in Figures 2 to 4, the collecting path 4 and paths 6a, 6b are belt conveyors all driven in the same direction, and the collecting zones 7a and 7b are collecting receptacles, each one located at one end of the respective belt conveyor. An additional collecting receptacle 7c placed at one end of the belt conveyor 4 to collect the bottles without a ferromagnetic marker is also provided. Furthermore, the electromagnet 5 is guided along a slideway bar 9 in a perpendicular direction to the running direction of the belt conveyors 4, 6a and 6b.

The ferromagnetic markers 3a and 3b can be embodied in various ways. For example, they may be thin flexible metal bands, as in the example of Figure 1, or coatings of a powder admixed with binders. Where it is anticipated that the bottles may arrive at the separation station in a crushed state, different types of markers would be preferably used, located so as to be always accessible to the magnetic action of the electromagnet. In this case, either tags 11 may be used for application to the bottle bottoms, or hoops 12 for application to the bottle necks near the bottle cap, or ring of tags 13 embedded or stuck around a circumference near the bottle neck (Figures 7 to 9) • The steps of the separation process of this invention are as described herein below.

On the labels 2a and 2b of bottles of the kinds la and lb are applied ferromagnetic markers 3a and 3b which are provided different to enable each of the bottle kinds la, lb, lc to be magnetically distinguish from one another. All bottles of different kinds are discharged onto the belt conveyor 4 and rearranged by the transport means 8 so as to have each at least a portion of the ferromagnetic marker facing the electromagnet regardless of their orientations on the belt conveyor 4. As they are moved under the electromagnet 5, the bottles of the kinds la and lb bearing ferromagnetic markers 3a and 3b will be attracted and held back, while the bottles of the kind lc bearing no ferromagnetic markers are allowed to move on with the belt conveyor 4. The electromagnet 5, with the bottles of the kinds la and lb stuck to the bottom, is then shifted perpendicularly to the running direction of the belt conveyors 4, 6a, 6b and positioned above the belt conveyor 6b. By decreasing the current flowing through the coil of the electromagnet 5, the latter is caused to release the bottles of the kind lb which bear the weakest magnetic markers onto the belt conveyor 6b, while the bottles of the kind la remain stuck to the bottom of the electromagnet 5. The electromagnet 5 is then moved above the belt conveyor 6a whereto it will, by decreasing the amplitude of the current flowing through its coil, release the bottles of the kind la. The bottles of the kind lc, bearing no ferromagnetic markers, and the bottles of the kind lb and la released from the electromagnet 5 onto the belt conveyors 6b and 6a, respectively, are ultimately discharged from the belt conveyors 4, 6b and 6a into the collecting receptacles 7c, 7b and 7a, respectively.

To recycle the bottles, as separated and collected by the above-described process, it may be necessary to remove the ferromagnetic markers from all the bottles. This operation is performed by the means 10 provided in the collecting receptacles 7a and 7b. In particular, as shown schematically in the example of Figure 3, this means 10 may be in the form of solutions wherein the bottles would be dipped for a sufficient time to have their labels unstuck.

Alternatively, the separation could be obtained by an application of heat to cause the plastics material to shrink and soften, and the markers be then removed in a centrifugal separator. This separator would include a rotary filter designed to let the molten plastics flow out through its holes, and to hold back the markers.

Claims

1. A process for separating non-ferrous articles of one kind from non-ferrous articles of other different kinds, characterized in applying to the non-ferrous articles of said one kind a distinctive type of ferromagnetic marker effective to make them magnetically distinguishable from the articles of other different kinds.

2. A process according to Claim 1, wherein the non-ferrous articles comprise plastic bottles for recycling.

3. A process according to Claim 2, wherein the ferromagnetic markers comprise tags applied to the bottle bottoms .

4. A process according to Claim 2, wherein the ferromagnetic markers comprise hoops applied to the bottles near their caps.

5. A process according to Claim 2, wherein the ferromagnetic markers comprise a ring of embedded or stuck tags extending substantially around a circumference near the bottle necks.

6. A process according to Claim 2, wherein the ferromagnetic markers are applied to labels on the bottles.

7. A process according to Claim 6, wherein the ferromagnetic markers are disposed on the labels so as to substantially encircle the bottles after the labels are applied.

8. A process according to Claim 1, wherein the process of separating the non-ferrous articles of one kind from non- ferrous articles of different kinds comprises the following steps : - discharging the articles bearing different ferromagnetic markers on a collecting path; moving an electromagnet adjacently to the collecting path so as to attract all the different articles bearing ferromagnetic markers; progressively shifting the electromagnet along a plurality of paths and decreasing in steps the amplitude of the current flowing through the electromagnet to cause the electromagnet to release articles of a predetermined kind on each path; collecting, at a plurality of collecting zones, the articles released by the electromagnet on each path; removing the ferromagnetic markers from the collected articles.

9. A process according to Claim 8, wherein the collecting path and the plurality of paths comprise a plurality of belt conveyors, all driven in the same direction.

10. A process according to Claim 8, wherein the plurality of collecting zones comprises a plurality of collecting receptacles, each located at one end of each conveyor for collecting the articles being progressively discharged from the electromagnet onto the belt conveyors, and for removing the ferromagnetic markers from the collected articles.

11. A process according to Claim 9, wherein the electromagnet can be moved above the belt conveyors along a perpendicular direction to the running direction of the belt conveyors.

12. A non-ferrous article, in particular a plastic bottle, suitably adapted to be separated from articles of different kinds, characterized in that it comprises a ferromagnetic marker .

13. An article according to Claim 12, wherein the ferromagnetic marker is applied to a label on the bottle.

14. An article according to Claim 13, wherein the ferromagnetic marker is disposed on the label so as to substantially encircle the bottle after the label is applied.

15. An article according to Claim 12, wherein the ferromagnetic marker is a tag applied to the bottle bottom.

16. An article according to Claim 12, wherein the ferromagnetic marker is a hoop applied to the bottle near its cap.

17. An article according to Claim 12, wherein the ferromagnetic marker is a ring of embedded or stuck tags extending substantially around a circumference near the bottle neck.