EP0873795A2 - Method and device for sorting broken pieces - Google Patents

Abstract

The stream of the fragments to be sorted is produced and the optical measuring data of these fragments are detected so that classification features can be formed from the measured data. The fragments in this stream are distributed as fractions to different channels in dependence on the classification features. The fragments are distributed in one sorting stage into more than two channels. One of the fractions is returned into the stream of fragments for a repeat detection of the measured data. A first class of fragments is fixed where the probability of the existence of the classification feature exceeds a predetermined high threshold value. A second class is where the probability is below a predetermined low threshold and a third class is where the probability is between the two thresholds.

Description

Technical field

(a) Erzeugen eines Stromes der zu sortierenden Scherben,

(b) Erfassen von optischen Meßdaten der Scherben in diesem Strom

(c) Bilden von Klassifizierungs-Merkmalen aus den Meßdaten

(d) Verteilen der Scherben in diesem Strom als Fraktionen auf unterschiedliche Kanäle in Abhängigkeit von den Klassifizierungs-Merkmalen

The invention relates to a method for sorting cullet, in particular cullet of different colors or different materials, with the steps

(a) generating a stream of the fragments to be sorted,

(b) Acquisition of optical measurement data of the cullet in this stream

(c) Forming classification features from the measurement data

(d) Distribute the cullets in this stream as fractions over different channels depending on the classification characteristics

(a) eine Sensoranordnung zum Erfassen optischer Meßdaten,

(b) Führungsmittel zum Vorbeiführen eines Stromes von zu sortierenden Scherben an der Sensoranordnung,

(c) eine Signalverarbeitungs-Einrichtung zur Gewinnung von Klassifizierungs-Merkmalen aus den Meßdaten der Sensoranordnung, und

(c) Effektoren, an welchen der Strom von Scherben vorbeigeführt ist und welche von der Signalverarbeitungs-Einrichtung nach Maßgabe der Klassifizierungs-Merkmale ansteuerbar sind, zur Verteilung der Scherben aus dem Strom von Scherben auf Kanäle.

The invention further relates to a device for sorting broken glass, in particular broken glass of different colors or different materials, comprising:

(a) a sensor arrangement for acquiring optical measurement data,

(b) guide means for guiding a stream of cullet to be sorted past the sensor arrangement,

(c) a signal processing device for obtaining classification features from the measurement data of the sensor arrangement, and

(c) Effectors, to which the stream of cullet is passed and which can be controlled by the signal processing device in accordance with the classification features, for distributing the cullet from the stream of cullet to channels.

State of the art

With conventional scale sorting devices, the material to be sorted is placed on a vibrating trough fed and isolated on a subsequent slide. On this slide or in In free fall, the items to be sorted are screened, with color or transparency of one Object is determined. If the material to be sorted is to be sorted out, it becomes outdoors Fall through a row of valves and nozzles using a blast of compressed air from the Carried parabola. The fragments that are not ejected form the continuous fraction. The ejected fragments form the ejection fraction.

With these devices either opaque foreign substances, so-called KSP (Ceramics, earthenware, porcelain), as well as incorrect colors in waste glass made of color-separated Collection ejected from the glass stream. There is a KSP separation and false color separation in two separate successive stages is required.

For sorting mixed glass according to the basic colors white, green and brown with the Conventional technology also requires two consecutive sorting levels.

Due to increasing recycling quotas, the requirements regarding the Purity of the glass with regard to foreign substances (KSP) and color. According to the regulations of the German glass association, the limit for KSP is 25g / t and for false colors in White glass at 0.05%. With optoelectronic sorting devices for broken glass, they are To achieve demands in general with great effort. Degree of separation of the Sorting devices are around 95 to 97%.

Whether this degree of separation is sufficient depends on the contamination of the goods to be sorted at the entrance to the processing plant. For KSP separation is generally one two-stage process with upstream manual sorting of larger objects required.

Because of the lower requirements regarding the color purity, one gets by for waste glass color-separated collection with a one-step process, although in As a rule, manual sorting is also required. In the Obtaining white glass from mixed color glass, the proportion of false colors is extremely high, so that again only in a two-stage process, but with low white glass yield the required purity can be achieved.

A method for sorting bulk material is known from DE 42 10 157 A1 which improves the quality of the sorting by optimizing Classification parameters are determined according to which the bulk goods are sorted.

DE 43 05 562 A1 describes a method for sorting packaging waste known in which the shape of the packaging or parts of the shape is detected and as Sorting criterion is used. However, this is not Shards of glass or KSP, but more or less complete Plastic packaging with defined shapes.

Disclosure of the invention

The invention has for its object the sorting of waste glass by color and Simplify contamination and improve the quality of sorting.

The invention is also based on the object of a sorting device for broken glass create an improved sorting and / or a higher cullet throughput than known devices of this type achieved.

According to the invention this object is achieved in that the fragments in one Sorting level can be distributed over more than two channels.

This allows a multi-level sorting system, in which successive sorting levels used to be replaced by a single sorting level. The use of only one sorting level has the advantage that the goods to be sorted can be sorted more quickly. The separation factor and the throughput are thus increased.

A sorting device with more than two channels can be mixed glass according to the three Sort basic colors and on the other hand false colors and impurities at the same time sort out.

Experience has also shown that one and the same colored shard when it runs through the sorting device again and again and is subjected to the color classification is a frequency distribution with a finite half-value range with regard to security the color classification results. In a certain number of cases, one Misclassification occurs. It’s a statistical phenomenon, which is largely due to the fact that the detection is only finite Dissolution occurs and the shard because of their large number of degrees of freedom at each Passage of the sensor creates a different image. The degrees of freedom are in the Translation regarding space and time and the rotation. There is even a roll on the slide possible.

Other disturbances can depend on the local condition of the slide and Outgoing shard neighborhoods. A very important effect is the change in Shard even with repeated passage of the sorting device. So can stick to dirt make reliable color detection impossible at the first passage. After this Ejection of this shard with compressed air and repeated feeding is this Shard has already been largely freed from buildup. Color recognition becomes important safer.

A measure of the reliability of the color classification can be made in each color classifier define. Is it e.g. a classification based on topologically defined Color areas, the distance to the edge of the color area is a measure of that Classification security. Any suitable threshold value function can be used Divide the color area into a safe and an unsafe area. The safe white area is assigned to the run, the safe false color area (non-white area) is assigned to the first ejection and the unsafe white and false color area is assigned to the second ejection.

The system according to the invention can therefore return the fragments of the channel have in which the shards are directed, in which the properties are not Security could be determined. These shards, in which neither a correct one Recognition that a correct ejection could still be ensured is then carried out again passed through the sorting device, so that the quality of the fragments to the Outputs can be significantly improved.

Since the sorting takes place in the mass flow, statistical density fluctuations result the shards. Although the area occupancy in the amount of the sensors is typically below 20% lies, densification areas of two or more fragments can arise, whereby Shards can also touch or even overlap.

An investigation is carried out to determine whether there are other objects in the vicinity of the Object assigned to the first ejection due to the color classification. By a shape analysis of the object can be observed e.g. by observing narrow points insist that the depicted object is actually two or more objects is composed. In all these cases there is a risk that with the expulsion of the Object in the first ejection fraction other objects that do not eject this are assigned due to the relatively low resolution of the blow-out process be ejected.

In this case, too, these insufficiently isolated objects become the second Ejection assigned and fed to the sorting device again. At the second passage is the probability that the same object is again in a compression zone is extremely low.

There is little danger for objects that persistently prove unsafe. This can be a good option for stubborn cullet deposits such as labels exists for desolation. To make sure that there is no excessive material accumulation arises in the cycle, the uncertainty areas are linked to the throughput, so that a setpoint is not exceeded. If the mass flow rate becomes too high, the area of uncertainty chosen accordingly smaller.

Embodiments of the invention are the subject of the dependent claims.

Embodiments of the invention are below with reference to the associated drawings explained in more detail.

Brief description of the drawings

Fig. 1

shows a plan view of a cullet sorting device with Return.

Fig. 2

shows a cross section through a cullet sorting device.

Preferred embodiment of the invention

1 is a top view of a cullet sorting device 10 with return. A Stream of mixed cullet 12 is fed to the vibratory conveyor 14 Sorting device 10 passed. The fragments 12 are separated so that one Illumination of the individual shards is possible.

The fragments 12 are sorted in the sorting device 10 and fall into three channels A, B and C on pull-out belts 16, 18 and 20. The shards 22 on the pull-out belt 16 fall, form the continuous fraction of the cullet to be sorted. The shards 24, that fall on the pull-out belt 18 form the first ejection fraction of the ones to be sorted Shards. The shards 26, which fall on the pull-out belt 20, form the second Ejection fraction of the fragments to be sorted.

In the present example, the second ejection fraction is opened via the extraction belt 20 an ascending conveyor belt 28 is guided and via a vibrating conveyor 14 connected slide 30 again mixed shards 12 for re-sorting added.

The scale sorting device 10 is shown in FIG. On the vibration conveyor 14 is a Deflector 32 arranged. The deflector 32 serves to reject oversizes and Long parts.

The vibration conveyor 14 ends behind the deflector in a rubber strip 40 that around deviates from the horizontal by a small angle. Fall from this rubber strip 40 the shards on a replaceable glass plate 42, which is at an angle against the Horizontal is inclined. The glass plate 42 forms the upper part of an inclined surface or Slide 44.

The middle part of the inclined surface 44 is blackened on its underside Glass plate 46 formed. The glass plate 46 is at a slightly larger angle than that Glass plate 42 inclined to the horizontal and forms the steeper part of the Inclined surface 44. The glass plate 42 lies on the upper end of the glass plate 46, see above that a small lead is formed. The lead may still be existing groups of broken glass further separated when passing.

At the lower end of the glass plate 46 there is an un blackened area, the one Window 48 forms. Light 50 emerges through a window 48 from a fluorescent tube 52 Achieving a higher radiation power is behind the fluorescent tube 52 Reflector 54 arranged. The light 50 falls on a sensor 56. The sensor sits in a housing 57, which is closed by a window 59. A wiper 58 holds that Window 59 free of dirt. Red / green filters 60 and 62 are arranged in front of the sensor 56. An aperture 64 at the entrance of the sorting device protects the sensor 56 Extraneous light. The fluorescent tube 52, the sensor 56 and the filters 60 and 62 form one Sensor arrangement 63 In a preferred embodiment, a combined Sensor arrangement used, on the one hand the colors of the fragments 12 and on the other Recognize KSP shards.

When the fragments 12 reach the window 48 individually via the glass plate 46 it is illuminated by the light 50. The transmittance of certain colors will determined by the sensor 56. These transmittances provide that Classification feature by which sorting takes place. A computer 65 determines the Presence of an object, its geometry and serves as a signal processing device for obtaining classification characteristics from the measurement data of the Sensor arrangement 63.

After leaving the glass plate 46, the fragments initially fall in a falling parabola 90 down through a passage 66. At the end of through channel 66 there are blowing devices 68 and 70 in the form of nozzles or as effectors Nozzles. The blowing devices 68 and 70 are also connected via valves 72 and 74 Compressed air reservoirs 76 and 78 connected. Behind the compressed air reservoirs 76 and 78 are the associated distribution boxes and valve controls 80 and 82 are arranged. It can a large number of valves can be arranged side by side in valve strips. in the present embodiment were valve strips with ninety-six or one hundred and ninety-two valves used per ejection.

The through-channel has one upstream of the blowing devices 68 and 70 Narrowing on.

The blowing devices 68 and 70 are inclined slightly downward and so towards one another arranged opposite to each other that there are air flows 84 and 86, when the valves are open 72 and 74 are blown out at a point 88 on the falling parabola 90 of the fragments 12 to meet.

The blowing direction of the blowing devices 68 and 70 is directed so far downwards that that, if anything, only a small airflow up towards the Sensor arrangement 63 and the inclined surface 44 leads. An upward current would Fall parabola 90 of the fragments 12 affect and excessive contamination lead in the area of the sensor arrangement 63. For this reason, the bottom of the device be designed so that an easy downward air discharge is possible.

If the sensor has a given transmittance with a given color notes, i.e. if a classification feature is met, the valves 72 remain and 74 closed and the fragments fall down in the fall parabola 90 in channel A. on the take-off belt 16 for the continuous fraction. This classification characteristic is not satisfied with a predetermined high probability, then the valve 74 opened and the shard blown out of its path by the blowing device 68. she falls then in channel B as the first ejection fraction 92 onto the withdrawal belt 18. All others Shards, i.e. all shards where the classification feature is not certain is present or is not present by the blowing device 70 in the channel C as second ejection fraction 94 is blown onto the further discharge belt 20 by the valve 72 is opened.

The second ejection fraction 94 is shown in FIG. 1 again on the Vibration conveyor 14 conveys and goes through the measuring and sorting process again. This ensures that all the fragments, e.g. neither with certainty than white glass are identifiable, but also not with certainty as KSP or colored glass are identified, go through a new measurement. The purity of the fractions will thereby significantly improved.

Optimally, the blowers 68 and 70 are not on the same side arranged because of the discharge cone because of the different size and shape of the Shards is very wide and the second blowing device is so far apart The first line should be that of drag, rotation of the shards and expansion the falling parabola 90 become so strong that the goods to be sorted are reliably discharged is no longer possible.

The trigger bands 16, 18, 20 are separated by flexible partitions 98 and 100 Cut. The bandwidth can be adjusted through the flexibility. Likewise, they are Page boundaries 102 and 104 designed flexibly. From the side borders 102 and 104 to the blowing devices 68 and 70 run baffles 106 and 108, see above that compressed air reservoir 76 and 78, valves 72 and 74, distribution box and Valve control 80 and 82 are protected from the shards. The baffles 106 and 108 diverge at an obtuse angle. This can blow the air Blow off blowing devices 68 and 70 freely.

The entire arrangement is surrounded by unscrewable plates 110 and 112. Above the compressed air reservoir, at the height of the inclined surface 44 and Measuring arrangement flaps 114 and 116 are arranged, the gas pressure springs 118 and 120 are burdened.

In this embodiment it was described how a run-through fraction, e.g. White glass from e.g. the false colors or KSP is separated. This creates only two Fractions on three channels.

But it is also conceivable and easily possible to work without feedback. Then it is separated into three fractions, e.g. White glass in the continuous fraction, False colors in the first ejection fraction and KSP in the second ejection fraction.

Claims (24)

Method for sorting fragments, in particular fragments of different colors or different materials, with the steps (a) generating a stream of the fragments to be sorted, (b) Acquisition of optical measurement data of the cullet in this stream (c) Forming classification features from the measurement data (d) Distribute the cullets in this stream as fractions over different channels depending on the classification characteristics
characterized in that (e) the cullets are divided into more than two channels in a sorting stage. A method according to claim 1, characterized in that one of the fractions is returned to the stream of cullet to record the measurement data again. A method according to claim 1 or 2, characterized in that (a) a first class of fragments is determined, in which the probability of the presence of the classification feature exceeds a predetermined high threshold value; (b) a second class of cullet is determined, in which the probability of the presence of the classification feature falls below a predetermined low threshold value; (c) a third class of fragments is given, in which the probability of the classification feature being present lies between the two threshold values, and (d) the shards are distributed to the channels according to these classes. Method according to Claim 3, characterized in that the fragments of the class in which the probability of the classification feature being present lies between the two threshold values are returned to the inlet of the sorting device. Method according to claim 5, characterized in that the threshold values for the classification are determined in such a way that the cullet throughput is less than a predetermined target value. Method according to one of claims 1 to 5, characterized in that (a) the fragments are passed into a first channel as the first ejection fraction by actuating a first effector, (b) the fragments are passed into a second channel by actuating a second effector as a second ejection fraction and (c) the cullets are passed into a third channel as a continuous fraction by not actuating both effectors. Method according to claim 6, insofar as it relates to one of claims 3 to 5, characterized in that the fragments of the continuous fraction are broken glass and the fragments of the first ejection fraction do not consist of glass. Method according to claim 6, insofar as it is related to one of claims 3 to 5, characterized in that the fragments of the continuous fraction consist of glass of a certain color and the fragments of the ejection fractions do not have this color or are not made of glass. Method according to Claim 1, characterized in that the fragments which are passed into a first channel are not made of glass and the pieces which are passed into the other channels are made of glass of a certain color. Method according to one of Claims 1 to 9, characterized in that the fragments are separated on an inclined surface before the optical measurement data are recorded. A method according to claim 10, characterized in that (a) the shards fall freely down at the end of the inclined surface, (b) the measurement data are recorded when the fragments are on the inclined surface or in free fall and (c) the fragments are separated into fractions in free fall by blowing. A method according to claim 11, characterized in that the cullets are blown in accordance with the classification features from two substantially opposite directions and are separated into three fractions, whereby (a) the first fraction is formed from the cullets, which are deflected when blowing from a first direction into a first channel, (b) the second fraction is formed from the fragments which are deflected when blowing from a second direction into a second channel, and (c) the third fraction is formed from the fragments that fall freely without blowing. A method according to claim 12, characterized in that the blowing is carried out by blowing or air currents which are inclined downwards at an angle. Method according to one of claims 1 to 14, characterized in that it is preceded or followed by one or more sorting steps. Device for sorting broken glass, in particular broken glass of different colors or different materials, comprising: (a) a sensor arrangement (63) for acquiring optical measurement data, (b) guide means (44) for guiding a stream of cullet (12) to be sorted past the sensor arrangement (63), (c) a signal processing device (65) for obtaining classification features from the measurement data of the sensor arrangement (63), and (c) Effectors (68, 70), to which the stream of fragments (12) is guided and which can be controlled by the signal processing device (65) in accordance with the classification features, for distributing the fragments (12) from the stream from fragments to channels (A, B, C),
characterized in that (d) more than two such channels (A, B, C) are provided. Apparatus according to claim 15, characterized in that the effectors are formed by blowing devices (68, 70), by means of the air currents of which the fragments (12) can be deflected into one channel (B, C). Apparatus according to claim 16, characterized in that three channels (A, B, C) and two blowing devices (68, 70) are provided and the blowing devices (68, 70) are arranged opposite one another. Device according to one of claims 15 to 17, characterized in that the blowing devices (68, 70) are inclined downwards at an angle. Device according to one of claims 15 to 18, characterized in that transmission or absorption values of the fragments (12) are applied to the signal processing device by the sensor arrangement (63) as optical measurement data for obtaining classification characteristics. Device according to one of claims 15 to 19, characterized in that the sorting device (10) has a feed with an inclined surface (44) on which the fragments (12) are separated before the optical measurement data are recorded. Apparatus according to claim 20, characterized in that (a) at the end of the inclined surface (44) a drop section (90) for the fragments (12) is provided, and (b) the sensor arrangement (63) for detecting the measurement data is arranged on the inclined surface (44) or the falling section. Device according to claim 20 or 21, characterized in that the inclined surface (44) consists of an upper and a lower glass plate (42, 46), of which the lower glass plate (46) has a steeper angle to the vertical than the upper glass plate ( 42) and the upper glass plate (42) rests on the lower one so that the two glass plates (42, 46) form a step. Device according to one of claims 15 to 22, characterized in that (a) a through channel (66) is formed between the inclined surface (44) and a wall (59) opposite this, through which the stream of fragments (12) passes, and (b) this through-channel (66) is narrowed upstream from the blowing devices (68, 70). Device according to one of claims 16 to 21, characterized in that the blowing devices (68, 70) are arranged in such a way that the blowing or air flows (84, 86) are guided through a common point (88) in the falling parabola (90) .

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