Classifying – separating – and assorting solids – Sorting special items – and certain methods and apparatus for... – Condition responsive means controls separating means
Reexamination Certificate
2000-04-03
2002-03-05
Nguyen, Tuan N. (Department: 3653)
Classifying, separating, and assorting solids
Sorting special items, and certain methods and apparatus for...
Condition responsive means controls separating means
C209S587000, C209S639000, C209S938000, C250S22300B, C250S225000
Reexamination Certificate
active
06353197
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to determination of characteristics of material, for example automatic inspection and sorting of discrete objects of differing compositions, e.g. waste objects.
2. Description of the Related Art Including Information Disclosed Under 37CFR 1.97 and 1.98
With the recent focus on collection and recycling of waste, the cost effectiveness of waste sorting has become an essential economic parameter.
In the “Dual System” in Germany all recyclable “non-biological” packaging waste excluding glass containers and newsprint is collected and sorted in more than 300 sorting plants.
Objects can be sorted on the basis of:
Size
Density/weight
Metal content (using eddy current effect)
Ferrous metal content (using magnetic separation)
but most objects such as plastics bottles and beverage cartons are today sorted out manually. Some beverage cartons contain an aluminium barrier and by eddy current induction they can be expelled from the waste stream. Generally, beverage cartons in their simpler form present a composite object consisting of paperboard with polymer overcoats on both their inside and outside surfaces.
A system known in Europe for separating-out from a stream of waste a fraction comprised of polymer-coated paperboard objects consists simply of operatives picking out such objects by hand, the operatives visually identifying the polymer-coated paperboard objects. Such manual picking-out of cartons can have a very high percentage hit rate, but is undesirably slow. We are aware of a proposal in Europe for a system in which an operative visually identifies polymer-coated paperboard objects and controls a robot to perform the picking-out of the objects in question.
Such robotic picking-out of cartons could have a very high percentage hit rate, but would be undesirably slow.
To make a positive identification by automatic means is very difficult. U.S. Pat. No. 5,615,778 discloses a process to sort waste mixtures by irradiating the waste objects with electromagnetic and/or acoustic waves, by picking up the waves emanating from each irradiated waste object in a signal processor to identify it, and by transmitting signals from the signal processor to a separator which sorts out the identified waste object. The apparatus may include a video camera to pick up the waves emanating from the waste object. A still photo camera, an UV or IR receiver, or a microphone, can be substituted for the video camera. One or more characterizing features of the object are detected and then evaluated by the signal processor. Examples of such characterizing features are the external shape of the object such as, for instance, the shape of bottles, cups, tubes and cubic shapes, as well as characteristic lettering, product names, company or manufacturer names, trademarks, colours and the like, which are present on the object. However, physical shape is normally quite distorted, making recognition very complex unless the printing pattern is made in a specially recognisable way, or the carton is equipped with a recognisable marker or tracer, which depends upon the willingness of manufacturers and their customers to limit particular markings to goods of particular compositions.
DE-A-3346129 discloses a system for sorting refuse containing waste glass, particularly hollow waste glass, in which system items of refuse of optional minimum particle size are separated from the rest of the refuse, those items are conveyed along a track in at least one line, pieces of green, brown and clear scrap glass are identified while being conveyed along the track, and the identified pieces are separately ejected as fractions after a time delay. In addition to the items consisting of flat glass, pieces of metal, ceramics, cork, plastics or clay are also identified, whereafter they and any pieces not identified are separated consecutively on further sections of the track (after the track section upon which the glass and other identified pieces are identified). The or each line in the track has its own colour recognition unit at a recognition station. Each stream of waste appears to consist of a single row of items. There may be a plurality of tracks in the form of respective conveyor belts advancing parallelly to each other and in a common direction. Separated-out fractions may be conveyed away by respective conveyor belts extending perpendicularly to the tracks.
JP-A-5-169037 discloses a system for accurately separating opaque foreign matter from transparent bodies, while they are being dropped from a conveyor. The falling transparent bodies and the opaque foreign matter are horizontally and linearly scanned by a laser beam, and the reflected light is detected by a CCD (cathode coupled device)-type image sensor. Whether the image is of the transparent body or opaque foreign matter is discriminated for each CCD block containing N-units, and air is injected from one nozzle block corresponding to the CCD block containing the opaque foreign matter and from the adjacent nozzle block.
Several sorting systems exist today that can sort a number of different plastics bottles/objects from each other when they arrive sequentially (i.e. one-by-one). The detection is based on reflected infrared spectrum analysis. To separate the various polymers a quite elaborate variance analysis has to be performed and thus detection systems become expensive. The objects being fed sequentially pass beneath the infrared spectral detector whereby infrared is shone onto the objects and the relative intensities of selected wavelengths of the infrared radiation reflected are used to determine the particular plastics compound of the plastics passing beneath the detection head. Downstream of the detection head are a number of air jets which blow the individual plastics objects into respective bins depending upon the plastics which constitutes the majority of the object.
A similar system is disclosed in U.S. Pat. No. 5,134,291 in which, although the objects to be sorted can be made of any material, e.g. metals, paper, plastics or any combination thereof, it is critical that at least some of the objects be made predominantly from PET (polyethylene terephthalate) and PS (polystyrene) as well as predominantly from at least two of PVC (polyvinyl chloride), PE (polyethylene) and PP (polypropylene), for example objects including: an object made predominantly from PET, an object made predominantly from PS, an object made predominantly from PVC and an object made predominantly from PE. A source of NIR (Near Infra Red), preferably a tungsten lamp, radiates NIR onto a conveyor sequentially advancing the objects, which reflect the NIR into a detector in the form of a scanning grating NIR spectrometer or a diode array NIR spectrometer. The detector is connected to a digital computer connected to a series of solenoid valves controlling a row of air-actuated pushers arranged along the conveyor opposite a row of transverse conveyors. The diffuse reflectance of the irradiated objects in the NIR region is measured to identify the particular plastics of each object and the appropriate solenoid valve and thus pusher are operated to direct that object laterally from the conveyor onto the appropriate transverse conveyor. The computer can manipulate data in the form of discrete wavelength measurements and in the form of spectra. A measurement at one wavelength can be ratioed to a measurement at another wavelength. Preferably, however, the data is manipulated in the form of spectra and the spectra manipulated, by analogue signal processing and digital pattern recognition, to make the differences more apparent and the resulting identification more reliable.
DE-A-4312915 discloses the separation of plastics, particularly of plastics waste, into separate types, on the basis of the fact that some types of plastics have characteristic IR spectra. In the IR spectroscopic procedure, the intensity of diffusely reflected radiation from each sample is m
Foss-Pedersen Geir
Johansen Ib-Rune
Mender Clas Fredrik
Tschudi Jon Henrik
Ulrichsen Borre Bengt
Andresen Tiedemanns-Jon H.
Nguyen Tuan N.
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