EP0734790A1 - Plastic objects sorting machine - Google Patents

Abstract

The sorter consists of a centrifugal separator in two sections - a chamber (2) which is spherical, truncated conical or trunco-spherical in shape, surrounded by a first horizontal peripheral track (3) with an outer rim (5) which has a gap in it, and a second, or sorting, track (8) round the outside of the first. The chamber (2) has a raised centre and is rotated about an axis inclined at 5-30 degrees to the vertical. The articles being sorted, e.g. bottle made from glass or plastics, such as PVC, PET, polyethylene or polypropylene, are scanned by sensors (7) and ejected, e.g. by blowers (10) into different containers.

Description

The invention relates to a machine for sorting objects, for example glass, plastic or any other similar material. Generally, this type of machine comprises at least one sensor capable of recognizing said objects to be sorted, said sensor delivering, during the phase of identification of said object, signals for the start and end of the object, when this object passes in front of the sensor. . The present invention therefore relates to an object sorting machine and more specifically relates to means of correctly scrolling the objects to be sorted in a restricted area in front of said sensor.

The purpose of the system is to sort objects and for example here the sorting of plastic bottles appearing in the normal appearance of bottles but also in the appearance of clumps, or shredded bottles of imprecise conformation, color and heterogeneous nature.

The sorting criterion depends on the sensor used chosen according to the properties of the objects to be identified (nature, color, conformation, chemical composition, physical properties ...).

For simplification, in the following description, the separation of plastic bottles of different compositions and / or colors is described, but the device described is suitable for the separation of all plastic objects or other materials, whatever their shape. Apparatus has already been proposed for separating glass bottles by optical sensors (EP-A-479756) or by other means (US-A-5314072).

Patent WO 92 / 07.232 describes a rectilinear mat for separating objects.

US Patent 3,900,107 describes a simple tank containing at its bottom a substantially horizontal disc requiring to use various means to raise the objects to be sorted from the disc to a separation mat for objects.

Patent WO 92 / 03.551 also describes a tank at the bottom in the shape of a relatively inclined disc.

By way of example, an object separation device is made up of 5 functional sub-assemblies (the reference numbers refer to FIG. 1 without limitation of the invention.) Which are described here for a better understanding. of the invention, the invention in itself being only the means (centrifugal bowl) which makes it possible to receive the spillage of the objects and to send them one by one in front of the sensor. This device includes:

At least one receiving hopper (1)

It is the point of supply for the object separation system or device; the filling of the hopper is carried out by a handling means (example a bucket loader). In the lower part of the hopper an extraction conveyor regulates the flow of the material to be sorted.

At least one screen

Of variable length, the screen is intended to evacuate the fragments as well as objects of reduced size not acceptable by the sorter.

At least one elevator (for example belt) (4)

It supplies the separator with constant flow.

At least one centrifugal bowl aligner separator (see Figure 2)

• Une cuve (2) sensiblement troncosphérique ou sphérique ou en forme de tronc de cône, (cette cuve n'a donc pas la forme cylindrique habituelle) possédant dans sa partie supérieure une première piste (3) périphérique horizontale limitée par une couronne (5) extérieure fixe (ou rive), interrompue partiellement sur sa longueur. La couronne a l'aspect d'une paroi circulaire en forme de bande verticale ; cette bande agit comme un petit muret dont la hauteur est de 1 à 4 fois environ (par exemple) la hauteur des objets à séparer et elle sépare la première piste de la deuxième piste définie ci-dessous (8).

This aligning separator is the object of the present invention, especially in combination with the sorting track described below. This subset is broken down into two parts:

• A tank (2) substantially troncospheric or spherical or in the form of a truncated cone, (this tank therefore does not have the usual cylindrical shape) having in its upper part a first horizontal peripheral track (3) limited by a crown (5) fixed exterior (or shore), partially interrupted along its length. The crown has the appearance of a circular wall in the form of a vertical strip; this band acts like a small wall whose height is 1 to 4 times (for example) the height of the objects to be separated and it separates the first track from the second track defined below (8).

• Un élément (9) choisi dans le groupe constitué par un cône ou un tronc de cône ou un tronc de sphère ou toute forme similaire, dont le sommet est orienté vers le haut, et qui est entraîné en rotation selon un axe incliné généralement de 5 à 30°, de préférence 10 à 25° (de 15° par exemple) par rapport a la verticale et tournant à l'intérieur de la cuve.

The tank is rotated along a substantially vertical axis and receives the objects to be sorted.

• An element (9) chosen from the group consisting of a cone or a truncated cone or a trunk of a sphere or any similar shape, the apex of which is oriented upwards, and which is rotated along an axis generally inclined by 5 at 30 °, preferably 10 to 25 ° (15 ° for example) relative to the vertical and rotating inside the tank.

The cone, trunk of cone or trunk of sphere fits into the tank; its diameter is substantially equal to that of the tank to the operating clearance.

In its rotational movement the disc or cone or truncated cone or trunk of a sphere drives the objects to its periphery. Arrived at the "high" point of the disc or cone or truncated cone or trunk of a sphere, its generator is at the level of the horizontal peripheral track. The objects are pressed against the shore by the action of centrifugal force and reach a first track (3). The width of the track is such that only one object can be there. Each object is thus isolated on its track. The interruption practiced in the shore (5) allows the passage of the isolated object on a second track (8) called sorting track (or firing track) defined below:

(5) At least one sorting track (8) substantially horizontal and tangent to said first track, so it is separated by said crown. (figure 2).

The sorting track is driven independently. Its speed of rotation, greater than or equal to that of the tank, makes it possible to increase the interval between objects.

The device according to the invention can be supplemented, for example, as follows:

The trajectory described by the sorting track is preferably divided into angular sectors. A sector, generally, the first sector, located immediately after the break in the shore, is reserved for the identification of the object. The mesh structure of the mat allows positioning of the sensor (7) on either side of the object to be identified. Most of the other sectors are used to collect identified and separate objects. The number of the following sectors depends on the selectivity that one wishes to bring to the objects. Each sector corresponds to a type of object to be sorted. Optionally, a sector, for example the last, is a scrap zone for badly identified or unidentified objects or can be used for any other particular recovery of objects not selected in the other sectors. The position of the sensor (7) on Figure 2 is not limiting.

An ejection system (10) (for example by forced air) is located under the sorting belt at each sector. Once ejected, the objects are guided to a specific silo.

The principle described above applies in particular to the sorting of plastic bottles made of different materials: polyvinyl chloride, polyethylene terephthalate, polyethylene, polypropylene ... and / or of different colors.

The purity level of the batches constituted is generally greater than 98%. The rates of sorted bottles can reach 18,000 bottles per hour.

The lots sorted by material are sent to different specialized recycling centers.

The sorting machine incorporates the sensor which allows the different materials to be recognized. The sensor used is, for example, a near infrared (NIR) spectrometer with factorial filters from BUHLER.

Bottles or other objects to be identified are illuminated with a light source (for example with halogen lamps) and measured without physical contact with the sensor.

The bottles or other objects are ejected by pushing compressed air. The blow guns used deliver a precise and measurable directional jet.

The entire installation is generally controlled by an automaton which mainly regulates the flow of bottles, dialogs with the sensor and controls the ejectors.

The sorter assigns the identified object to the specific silo. The sorting track is equipped with an angular position sensor. The relative angular position of each receiving silo with respect to the reference position of the identification sensor is previously measured and then parameterized at the level of the PLC.

During the identification phase, the sensor delivers the object start and end signals to the PLC. These signals are synchronized by the automaton with the information delivered by the angular position sensor in order to measure the length of the object. The precision of this synchronization also makes it possible to delimit areas of the object to be ignored or to be treated in particular (bottle stopper, label, ink, bar code, paint, etc.). Knowledge of this length makes it possible to determine the optimum point of impact for the shot.

• Une cuve sensiblement troncosphérique ou en forme de tronc de cône sphérique possédant dans sa partie supérieure une première piste périphérique horizontale limitée par une couronne extérieure fixe ou rive, interrompue partiellement sur sa longeur, la cuve étant entraînée en rotation selon un axe vertical et recevant les objets à trier.
• Un disque, ou un cône ou un tronc de cône ou un tronc de sphère, dont le sommet orienté vers le haut, est entraîné en rotation selon un axe incliné par rapport à la verticale et tournant à l'intérieur de la cuve, ledit disque, ou cône ou tronc de cône ou tronc de sphère s'inscrivant dans la cuve; son diamètre étant égal environ à celui de la cuve au jeu de fonctionnement près.

The device according to the invention therefore comprises at least one aligner separator with a centrifugal bowl, this sub-assembly breaking down into two parts:

• A tank that is substantially troncospheric or in the shape of a spherical truncated cone having in its upper part a first horizontal peripheral track limited by a fixed outer ring or rim, partially interrupted along its length, the tank being driven in rotation along a vertical axis and receiving the objects to sort.
• A disc, or a cone or a truncated cone or a trunk of a sphere, the top of which faces upwards, is rotated along an axis inclined relative to the vertical and rotating inside the tank, said disc , or cone or trunk of cone or trunk of sphere inscribed in the tank; its diameter being approximately equal to that of the tank to the operating clearance.

The device according to the invention applies to the separation of objects of sizes, shapes, colors, and variable masses. The objects to be sorted are for example glass or plastic bottles.

The device is particularly suitable for sorting broken, shredded or crushed plastic bottles (provided that they are not welded or glued, entangled together by crushing procedures). The device is also suitable for sorting plastic packaging of all kinds, for example laundry packaging, cleaning products, food products (oil containers), automotive products, gardening products, fertilizers or all similar types of packaging. . We can sort mixtures of all the objects mentioned above.

Claims (11)

Device for the separation of objects comprising: • At least one centrifugal bowl aligner separator, this separator breaks down into two parts: - A substantially troncospheric or spherical tank or in the shape of a truncated cone having in its upper part a first horizontal peripheral track limited by a fixed outer ring or rim, partially interrupted along its length, the tank being driven in rotation about a substantially vertical axis and receiving the items to be sorted. - An element chosen from the group consisting of a cone, a truncated cone, a sphere trunk or any equivalent shape, the top of which is oriented upwards and is rotated along an inclined axis (generally from 5 to 30 ° ) with respect to the vertical and rotating inside the tank, the cone inscribing itself in the tank, its diameter being approximately equal to that of the tank, except for the operating clearance, said element being inscribed in said tank, its diameter being substantially equal to that of the tank. • - At least one second track called sorting track located at the periphery of said first previous track, substantially horizontal and tangent to said first track from which it is separated by said ring, this sorting track being driven independently. Device according to Claim 1, in which the trajectory described by the sorting belt is further divided into angular sectors, a sector generally located immediately after the break in the shore, being reserved for identifying the object, the track sorting system having a mesh structure, the mesh structure of the mat authorizing positioning of a sensor on either side of the object to be identified, most of the other sectors being used for collecting identified and separate objects. Device according to one of claims 1 and 2 applied to the separation of objects of varying sizes, shapes, colors and masses. Device according to one of claims 1 to 3, further comprising upstream of the aligner separator: • At least one receiving hopper, • At least one screen intended to evacuate the fragments as well as objects of reduced size not acceptable by the sorter. Device according to one of claims 2 to 4 in which, during the phase of identification of said objects, the sensor delivers to a PLC signals of start and end of object, these signals being synchronized by the PLC with the information delivered by the angular position sensor to measure the length of the object. Device according to one of claims 1 to 5 applied to the sorting of bottles. Device according to one of claims 1 to 6 applied to the sorting of glass bottles. Device according to one of claims 1 to 6 applied to the sorting of plastic bottles. Device according to one of claims 1 to 6 applied to the sorting of plastic bottles, broken, shredded or crushed. Device according to one of claims 1 to 6 applied to the sorting of plastic packaging for detergents, food products, cleaning products or the like. Device according to one of claims 7 to 10 applied to the sorting of mixture of objects.

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