Method and device for extracting by suction foreign matter from a stream of bulk material

(42) Date of commencement of the patent: 15. 5. 1993 (45) Date of issue: 27.12.1993

<td>(56) Documents:</td><td>(73) Patent owner:</td>

<td>DE-0S3713435 US-A 4759840 DE-0S3708180</td><td>BINDER + CO AKTIENGESELLSCHAFT A-8200 GLEISDORF, STYRIA (AT).</td>

<td></td><td>(72) Inventor:</td>

<td></td><td>GSCHWEITL KARLHEINZ GROSSPESENDORF, STEIERMARK (AT).</td>

(54) METHOD FOR EXTRACTION OF FOREIGN BODIES FROM A SHEET FLOW (57) The invention relates to a method for suction of foreign bodies from a bulk flow, comprising the following steps:

Transport of the bulk material flow via a conveyor to a suction nozzle;

Dropping the bulk material flow over an edge of the first conveyor;

Sucking the foreign matter through the nozzle;

Removal of the bulk material flow via another

Conveyor.

As a result, an improved suction effect is achieved. Furthermore, the invention relates to a device for carrying out this method.

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AT 396 878 b® eerasas

The invention relates to a method for sucking debris from a bulk material flow, as well as a device for carrying out this method.

It is necessary in many areas of technology from a bulk flow lighter components sucked by means of a suction device and thus to clean the bulk material flow. So it is z. B. required in the glass recycling, in the flow existing paper or aluminum parts, such as bottle caps to deposit in this way.

Devices are known in which the bulk material flow is transported via a conveyor and is performed under a suction nozzle. This conveyor can be designed as a conveyor trough, conveyor chute or sieve. The transport takes place either by means of the inclined conveyor by means of gravity or by the oscillating conveyor principle.

The degree of separation of such known conveyors is limited, since only the foreign body located on the surface of the bulk material flow can be safely sucked off. In order to achieve somewhat higher separation levels, it is necessary in such devices to allow only a very small amount of bulk flow, which in turn sets the performance of such device narrow limits

Furthermore, from DE-A 37 08 180, DE-A 37 13 435 or from US-A 4,759,840 air classifiers are known in which the separation of mixtures takes place in a compressed air stream. In the recycling of glass, however, such air classifiers have not been able to prevail, because the very irregular size distribution of glass fragments can lead to blockages.

Object of the present invention is to provide a method for sucking debris from a bulk flow with the high separation efficiency at high flow rates can be achieved. Furthermore, an apparatus for carrying out the method should be proposed.

The method according to the invention is characterized by the following steps:

- Transport of the bulk material flow via a conveyor to a suction nozzle;

- Abweifen the bulk material flow over an edge of the first conveyor;

- Aspirate as foreign body over the nozzle.

- Removal of the bulk material flow üa another conveyor.

It is essential in the method according to the invention that the suction is not limited only to the bulk material flow transported from a conveyor, but also detects the parts in free fall. Naturally, suction is also carried out at the exit edge of the nozzle, so that the material flow located on the wide conveyor is also subjected to cleaning. It is obvious that, due to the dropping from the first conveyor to the further conveyor, the material flow is redistributed, so that now other particles lie on the surface and are subjected to the suction.

It is also important that the removal of the foreign body is done by suction and not by blowing

The invention further relates to a device for sucking debris from a bulk material flow with a conveyor for transporting the bulk material flow and a nozzle disposed substantially above the conveyor for sucking the foreign body.

In the apparatus according to the invention it is provided that the conveying device in the area da nozzle has a discharge edge and that a further conveying device is provided for transporting the discarded bulk material flow.

As already stated above, conveyors can be designed as conveyor troughs, conveyor chutes or sieves. The discharge edge can be avisgebildet as a small survey to control the discharge of the bulk material flow.

It is preferably provided that the nozzle on the side of the incoming bulk material flow has a variable in height flap. The adjustment of the height of the flap to the bulk material flow can be done manually or automatically.

It is particularly favorable if the nozzle has a pivotable flap on the side of the transported bulk material flow. The flap is pulled inward by the negative pressure in the nozzle. However, it is possible for the flap to avoid at larger flow rates or occurrence of individual, larger particles to the outside. Furthermore, it is possible to determine the flap in a swung-out position.

In the following the invention will be explained in more detail with reference to an embodiment shown in the figure. The inventive device consists of a first conveyor (1) which is provided at its end with a discharge edge (2). Below this conveyor (1) a further conveyor (3) is arranged in the region of the discharge edge (2) a suction nozzle (4) is provided. The nozzle (4) has on the side of the incoming material flow a flap (5) which is adjustable in height (b). On the opposite side, a further flap (6) is provided, which is designed pivotable about a point (6a) and thus also in its height (a) is adjustable. This flap (6) can be freely swinging and / or fastened.

Since air flow sucked in through the nozzle (4) flows through the device in different ways. However, the device according to the invention is designed so that the main part of the air flow through the gap (7)

-2AT396878B is fed between the first conveyor (1) and the further conveyor (3). However, it is obvious that certain air flows immediately under the flaps (5) and (6) in the nozzle (4). Due to the adjustability of these flaps (5) and (6), these air currents should be kept relatively low. Another possibility for the air flow is given by the fact that the conveyors (1) and (3) are designed to be permeable to air in a conventional manner. This can be done either by the fact that it is vibrating screens or ventilation slots are provided in the case of conveyor slips, thereby enforcing that a certain air flow also passes through the on the conveyor (1) located bulk material flow and loosens this