EP1930090B1 - Method and device for eliminating foreign bodies - Google Patents

Abstract

The method involves directly conveying tobacco stream into the detection area of a foreign material detection laser (20) via compressed air (11). Foreign materials (17) in the tobacco stream are identified by the foreign material detection laser based on at least one characteristic. The detected foreign materials are removed from the tobacco stream.

Description

The invention relates to a method and apparatus for foreign body separation from a tobacco stream.

A corresponding device is for example from the US 6,332,543 B1 the applicant known. In this known device, by means of conveyors, in particular a conveyor trough and conveyor belts, a stream of tobacco is brought into the region of an optical foreign body detection device. Once a foreign body is detected in the tobacco stream by means of the foreign body detection device, the or the foreign body from the tobacco stream are separated by means of compressed air transversely to the conveying direction.

EP 1 576 897 A1 discloses a device for scanning and sorting tobacco leaves, wherein the tobacco leaf stream is raised by means of a current air source and at a speed is accelerated so that the tobacco particles are separated. Via a corresponding channel, the lifted tobacco leaves are conveyed to a scanning device, so that the tobacco leaf stream is scanned in the channel by the scanning device. Subsequently, unacceptable tobacco leaves are removed by a blast of compressed air.

It is an object of the present invention to specify a further variant of a method and a device for foreign body separation from a tobacco stream.

This object is achieved by a method for foreign body separation from a tobacco stream, wherein the tobacco stream is conveyed directly into the region of a foreign body detection device with compressed air and wherein by means of the foreign body detection device based on at least one property foreign bodies are recognized in the tobacco stream and then removed from the tobacco stream, wherein the Tobacco flow is tapered transversely to the conveying direction. By means of the method according to the invention, it is possible in particular to convey the tobacco stream and the foreign bodies present in the tobacco stream at a higher speed than in the prior art, so that, with the same performance of the method, a device carrying out the method which has a smaller construction can be used can. The tapering of the tobacco stream transversely to the conveying direction results in improved foreign body recognition.

In the context of the invention, property means in particular an optical property of the tobacco or of the foreign body such as brightness, shape and / or color or another physical property, such as the humidity, the specific weight or the provision of corresponding elements (carbon or metals, etc.). The foreign object recognition preferably takes place by means of a detection of the brightness and / or the color of the objects contained in the tobacco stream. By objects is meant in particular tobacco, tobacco leaves, cut tobacco and foreign matter. Preferably, the speed of the tobacco stream is between 6 m / s and 30 m / s, in particular between 17 m / s and 30 m / s. Due to the preferred speed, a very effective promotion of the tobacco stream is provided.

When the tobacco stream pulled apart across the conveying direction is excreted when leaving foreign bodies little tobacco or tobacco leaves or cut tobacco. In addition, this allows an improved detection rate of foreign bodies, since a relatively thin layer of tobacco stream can be evaluated correspondingly transversely to the conveying direction of the tobacco stream with the foreign body recognition device. The tobacco stream is preferably also pulled apart transversely to the measuring direction of the foreign body recognition. The direction of foreign body detection and the conveying direction are preferably also transverse to each other.

According to the invention, the tobacco stream is tapered in the direction of foreign body recognition. As a result, the foreign body detection can be done very efficiently and with high efficiency. Only a thin layer of the tobacco stream has to be examined for foreign bodies, whereby the foreign bodies can be better detected by smaller overlaps with tobacco. In the context of the invention, the direction of the foreign body detection, in particular in an ultrasonic measurement method, the direction of the ultrasonic waves transmitted to the tobacco stream or in a microwave method, the direction of the directed to the tobacco stream microwaves.

Preferably, the foreign body (s) are removed from the tobacco stream with compressed air. Alternatively, foreign bodies can also be removed from the tobacco stream by means of a fluid flow, for example a water jet. If after the foreign body detection of the tobacco stream is further promoted by suction, an uninterrupted tobacco stream is possible and correspondingly high throughput rates are possible. Preferably, the tobacco stream is at least partially conveyed substantially horizontally. In this embodiment of the invention, it makes sense to achieve tobacco flow velocities of at least 12 m / s, which is a Conveying air velocity of about 17 m / s corresponds. Conversely, if the tobacco stream is at least partially conveyed substantially vertically, gravity may also be exploited and the velocity of the tobacco stream or velocity of compressed air, which then contributes to conveying the tobacco stream, may be lower.

The object is further achieved by a device for foreign body separation from a tobacco stream, wherein a device supplying the tobacco to a foreign body detection device (supply device) and a Fremdkörperabscheidevorrichtung is provided, wherein the supply device for conveying the tobacco stream comprises a compressed air source, wherein the supply device is closed in cross-section Channel, in which the tobacco stream is promoted, the channel ends immediately before the foreign body detection device and / or the Fremdkörperabscheidevorrichtung open, wherein the channel is at least partially formed in the conveying direction in a direction transverse to the conveying direction tapered.

The device according to the invention can be made very small by using a compressed air source and the associated relatively high conveying speeds of the tobacco stream. Preferably, there is a compressed air flow in the feeder, which promotes the tobacco flow. In particular, the compressed air flow directly promotes the tobacco flow to the foreign body detection device. By the measure that the supply device comprises a channel closed in cross-section, in which the tobacco stream is conveyed or is conveyed, a particularly simple and inexpensive embodiment of the device according to the invention is given. Characterized in that the channel immediately before the foreign body recognition device and / or the Fremdkörperabscheidevorrichtung open ends, a particularly good deposition rate of foreign bodies is given. A particularly good dosage is possible when tobacco is conveyed through a lock in the compressed air stream. The lock is preferably a rotary valve.

The foreign body detection efficiency is increased when the channel is at least partially tapered in the conveying direction in a direction transverse to the conveying direction. If the channel in the conveying direction is at least partially pulled funnel-shaped apart, a particularly effective and tobacco-saving deposition of foreign bodies is possible. The channel is preferably designed at the exit in the form of a rectangular nozzle, so that an increase in speed occurs at the tobacco outlet. The cross section is then preferably reduced at the outlet. A particularly simple foreign object recognition is possible when the foreign body recognition device is optical.

Preferably, the channel extends in the conveying direction of the tobacco stream beyond the Fremdkörperabscheidevorrichtung out. By means of this preferred embodiment of the device according to the invention, a very efficient tobacco flow can be achieved, as a result of which the foreign body recognition rate is increased.

Preferably, the channel is closed at least on one side in the region of the foreign body separation device or comprises a lid. By virtue of this measure, a flow can be achieved by preferably utilizing a Coanda effect on the closed side of the channel or on the side of the channel provided with a lid, which enables a very good foreign body detection rate.

Preferably, at least one wall of the channel is at least partially straight in the conveying direction. Preferably, two opposite walls, in particular preferably two opposite narrower side walls of the channel are at least partially straight. The straight formation of the at least one wall is preferably adjacent to the end of the channel at which the foreign body detection device and / or the foreign matter separation device is disposed downstream.

Fig. 1

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung zur Fremdkörperabscheidung,

Fig. 2

eine schematische Darstellung einer alternativen Ausführungsform der erfindungsgemäßen Vorrichtung zur Fremdkörpererkennung,

Fig. 3

einen Teil einer weiteren Ausführungsform einer Vorrichtung zur Fremdkörpererkennung in schematischer dreidimensionaler Darstellung,

Fig. 4

einen Teil einer weiteren Ausführungsform einer Vorrichtung zur Fremdkörpererkennung in schematischer dreidimensionaler Darstellung, und

Fig. 5

eine schematische Schnittdarstellung einer alternativen Ausführungsform der erfindungsgemäßen Vorrichtung zur Fremdkörpererkennung.

The invention will be described below without limiting the general inventive idea by means of embodiments with reference to the drawings. With regard to the disclosure of all unspecified in the text details of the invention, reference is expressly made to the drawings.
Show it:

Fig. 1

a schematic representation of a device according to the invention for foreign body separation,

Fig. 2

a schematic representation of an alternative embodiment of the inventive device for foreign body detection,

Fig. 3

a part of a further embodiment of a device for foreign body recognition in a schematic three-dimensional representation,

Fig. 4

a part of another embodiment of a device for foreign body detection in a schematic three-dimensional representation, and

Fig. 5

a schematic sectional view of an alternative embodiment of the inventive device for foreign body detection.

Fig. 1 shows a schematic representation of a device according to the invention for foreign body separation. A tobacco feed device 10 is shown, which in particular comprises a tube 14, in which a stream of tobacco 16 in the conveying direction 28 is generated by a compressed air flow 11 generated by a compressed air source 30. Tobacco, for example, from a chute or a tobacco pipe 25, which is conveyed in the conveying direction 26 in the tobacco pipe 25, metered via a rotary valve, provided in the conveying direction 27 in the pipe 14 and contributes to the tobacco stream. In the tobacco stream, which is introduced into the tube 14 and is conveyed accordingly, are also foreign body 17. The tube 14 is a foreign body detection device, in this case comprising a laser 20, which generates a fan beam 21 by means not shown optics, and a CCD line (Charged Coupled Device line) 22, which may also be a camera, tapered in one direction and formed in a direction rotated by 90 ° widening direction and ends in a nozzle 15, the in Fig. 3 is shown. The tube 14 is correspondingly flattened in the region of the nozzle 15 and pulled apart, so that the tobacco 16 is pulled apart in the tobacco stream and a thinner layer passes through the fan beam 21, so that the efficiency of foreign body detection is increased.

A correspondingly recognized foreign body 17 is detected, for example, by a larger absorption of the beam spatially resolved via the CCD line 22 and eliminated by activating a nozzle 23 by means of compressed air 29 in the separation direction 18 from the tobacco stream. The tobacco stream is substantially or completely exempt from the foreign bodies 17 conveyed away by suction 12 in the discharge pipe 24. It makes sense to provide the suction air 12 in the discharge pipe such that all tobacco components 16 of the tobacco stream are taken.

Fig. 1 Figure 3 illustrates a horizontal embodiment of the invention in which the tobacco stream consisting of tobacco parts 16 is conveyed substantially horizontally.

In Fig. 2 an alternative embodiment of the device according to the invention is shown schematically, in which a vertical conveying of the tobacco happens. In addition, the tobacco pipe 25 is designed obliquely opening into the tube 14 and also the rotary valve 13 is not directly opening into the tube 14. Otherwise, the features corresponding to those Fig. 1 , However, in this case the compressed air speed 11 does not have to be set as high as in the exemplary embodiment according to FIG. Fig. 1 , because in addition to the compressed air and the earth's gravity plays a role.

Fig. 3 shows a schematic section of a device according to the invention in three-dimensional representation. In particular, the fanned out or pulled apart and flattened tube 14 in the nozzle region 15 is visible. The tube 14 is rectangular or square in cross section. However, it can also be given a different form. Furthermore, it is shown by corresponding arrows 29 that spatially resolved corresponding foreign body in the tobacco stream 16 can be removed from this, so that a slight tobacco loss arises here. Furthermore, a nozzle strip 33 is also shown, which has corresponding individual nozzles 23. The nozzles 23 are in Fig. 3 only indicated schematically. These are preferably closer together and it is preferred a larger number than shown provided.

Instead of the illustrated optical foreign body detection, any other conceivable foreign body detection can be used such as, for example, a foreign body detection based on heat, sound waves or microwaves.

For foreign body separation with optical methods, the product, ie the tobacco stream or the tobacco should be spread so that the camera or the laser scan has a clear view or access to the product surface. In order to achieve a good reject rate, the quality of the product presentation is at least as important as the image processing technology. The spreading systems known in the art operate at speeds of tobacco flow in the range up to 5.5 m / s and in a free fall at 3.0 m / s. For the optical recognition, it makes sense to spread the tobacco stream or the tobacco to a monolayer, whereby the basis weight is very low, so that a corresponding device according to the prior art has a relatively large useful width. In addition, it is relatively difficult in the prior art to achieve a good monolayer or a thin layer of tobacco in the tobacco stream.

Essential to the invention is the pneumatic conveying of the tobacco stream. In this case, correspondingly high speeds between 16 m / s and 30 m / s are possible. Known CCD line scan cameras offer scan rates or frame rates or readout times that can fully inspect the product surface even at these speeds. By the invention it is possible to present a stream of tobacco so that at a correspondingly high speed, in particular visually inspected, foreign matter with air nozzles or water nozzles are also ejected selectively can. This has the advantage that the corresponding apparatus for foreign body separation can have a smaller width and that a better separation of the tobacco in the tobacco stream is made possible.

FIG. 4 shows a further schematic three-dimensional representation of a part of another embodiment of a device for foreign body detection.

In relation to FIG. 3 In particular, the channel 14 is configured differently. Two opposing walls 50 and 51 are shown, which are arranged substantially parallel to each other and straight. This means that they are not tapered in the outlet region or in the nozzle region 15, but continue to be straight or continue parallel to one another. In contrast, the lower wall 52 and the upper wall 53 in the region 15 in the conveying direction of the compressed air 11 is tapered to achieve a nozzle effect. Upstream of the nozzle area 15, the lower wall 52 and the upper wall 53 may also be parallel to each other.

Compared to FIG. 3 is the distance between the channel 14 and the discharge pipe 24 slightly further to a computing unit, which is used to control the nozzles 23 to the nozzle bar 33 with appropriate foreign body detection by detecting a corresponding foreign body by means of the CCD line 22, even at high conveying speeds timely control of the corresponding nozzle 23 to allow.

FIG. 5 shows a further embodiment of the inventive device for foreign body detection in a schematic sectional view. This is a one-sided closed Channel 14. In this unilaterally closed channel 14, the air flow creates by utilizing the so-called Coanda effect to the rear wall 45 at. After detecting a foreign body by means of the camera 46, the foreign body in the observation plane 48 through the window 47 detects, after appropriate time delay depending on the conveying speed of the tobacco stream incl. The foreign body of the foreign body 40 by a pressure generated by the air nozzle 42 surge 43 from the conveying direction Deflected 28 so that the foreign body 40 reaches the deflected trajectory 44. As a result, the foreign body 40 is discharged from the channel 14. The channel 14 is configured such that in the conveying direction before, that is upstream of the air nozzle 42 takes place a reduction in the cross-sectional area of the channel 14, and in the region in which the freed of the foreign body 40 tobacco stream is further promoted, the cross-section initially increased slightly In order that the camera 46 detects the foreign body 40 so early that sufficient computing time for the identification of the foreign body and the driving of the air nozzles 42 remains, the position of the camera 46 is correspondingly far enough In front of the nozzle 42 and the nozzles 42. It can thus in the nozzle 42 shown schematically also to a nozzle bar according to the FIG. 3 or 4 act.

The back wall 45 is substantially continuous, that is, the channel 14 extends beyond the foreign body separator. The rear wall 45 is opened only in the region of the nozzle 42 through the nozzle opening, preferably circular, which does not lead to corresponding flow disturbances, since the interruption is sufficiently small.

The camera 46 has a separate viewing opening in the channel 14, which can also be closed by a transparent material, such as glass, in the form of a window 47. It can also be provided for this purpose a corresponding opening, which manages without windows.

Instead of the continuous rear wall 45 may also be provided a lid, which is not shown in the figures. The lid serves, for example, the upper area between the channel 14 and the discharge pipe 24 in the FIGS. 1 . 3 and 4 cover, and possibly also the side walls. The channel 14 may be correspondingly connected to the discharge pipe 24 or be integral, so far reaching that the area between the channel 14 and the discharge pipe 24 to the area necessary for the discharge of the foreign body, in particular in the discharge inlet area is. The exit area for the foreign bodies can, as in FIG. 5 is hinted at, optionally designed to be more open.

LIST OF REFERENCE NUMBERS

10

Tabakzuführvorrichtung

11

compressed air

12

suction

13

rotary valve

14

pipe

15

nozzle area

16

tobacco

17

foreign body

18

deposition direction

20

laser

21

ray fan

22

CCD line

23

jet

24

Abförderrohr

25

tobacco pipe

26

conveying direction

27

conveying direction

28

conveying direction

29

compressed air

30

Compressed air source

33

nozzle bar

40

foreign body

42

air nozzle

43

pressure surge

44

deflected trajectory

45

rear wall

46

camera

47

window

48

observation plane

50

wall

51

wall

52

wall

53

wall

Claims (16)

1. Method of removing foreign bodies from a tobacco flow (16), which tobacco flow (16) is conveyed by compressed air (12) directly into the region of a foreign body detection device (20, 22, 46), and foreign bodies (17) in the tobacco flow (16) are detected by means of the foreign body detection device (20, 22, 46) on the basis of at least one property and then removed from the tobacco flow (16), and the tobacco flow tapers transversely to the conveying direction and in the direction in which the foreign bodies are detected.
2. Method as claimed in claim 1, characterised in that the foreign bodies are detected by detecting the brightness, shape and/or colour of the objects (16, 17) contained in the tobacco flow (16).
3. Method as claimed in claim 1 or 2, characterised in that the speed of the tobacco flow (16) is between 17 and 30 m/s.
4. Method as claimed in one of claims 1 to 3, characterised in that the tobacco flow (16) is pulled apart transversely to the conveying direction (28).
5. Method as claimed in one of claims 1 to 4, characterised in that the foreign bodies (17) are removed from the tobacco flow (16) by means of compressed air or a fluid flow.
6. Method as claimed in one of claims 1 to 5, characterised in that, once the foreign bodies have been detected, the tobacco flow (16) is conveyed onwards by means of aspirated air (12).
7. Method as claimed in one of claims 1 to 6, characterised in that the tobacco flow (16) is conveyed at least partially substantially horizontally.
8. Method as claimed in one of claims 1 to 6, characterised in that the tobacco flow (16) is conveyed at least partially substantially vertically.
9. Device for removing foreign bodies from a tobacco flow (16), with a device (feeding device (10)) which feeds the tobacco (16) to a foreign body detection device (20, 22, 46) and a foreign body separating device (23, 42), characterised in that the feeding device (10) for conveying the tobacco flow (16) comprises a compressed air source (3), and the feeding device (10) comprises a passage (14) with a closed cross-section in which the tobacco flow (16) can be conveyed, and the passage (14) terminates in an open arrangement immediately upstream of the foreign body detection device (20, 22, 46) and/or foreign body separating device (23, 42), and in the conveying direction (28) at least portions of the passage (14) are of a tapering design in a direction extending transversely to the conveying direction (28) and in the direction in which the foreign bodies are detected.
10. Device as claimed in claim 9, characterised in that a compressed air flow (11) for conveying the tobacco flow (16) prevails in the feeding device (10).
11. Device as claimed in claim 9 or 10, characterised in that tobacco (16) can be conveyed into the compressed air flow (11) via a gate (13).
12. Device as claimed in one of claims 9 to 11, characterised in that the passage (14) extends beyond the foreign body separation device (23, 42) in the conveying direction (28) of the tobacco flow (16).
13. Device as claimed in claim 12, characterised in that the passage (14) is closed or has a cover at least at one end in the region of the foreign body separating device (23, 42).
14. Device as claimed in one of claims 9 to 13, characterised in that the passage (14) diverges in a funnel shape in at least certain portions in the conveying direction (28).
15. Device as claimed in one of claims 9 to 14, characterised in that at least one wall (50 - 53) of the passage (14) is of a straight design in at least some portions in the conveying direction (28).
16. Device as claimed in one of claims 9 to 15, characterised in that the foreign body detection device (20, 22, 46) is of an optical type.

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