EP1583618B1

EP1583618B1 - Method and arrangement for the sorting of refuse sacks

Info

Publication number: EP1583618B1
Application number: EP03812407A
Authority: EP
Inventors: Christer ÖJDEMARK; Christian TORÄNG
Original assignee: OPTIBAG SYSTEMS AB
Current assignee: Envac Optibag AB
Priority date: 2002-12-04
Filing date: 2003-12-03
Publication date: 2010-12-01
Anticipated expiration: 2023-12-03
Also published as: DE60335213D1; WO2004050264A1; ATE490031T1; NO20052686L; NO20052686D0; DK1583618T3; AU2003302596A1; NO327137B1; EP1583618A1; SE0203587D0; SE0203587L; SE524476C2

Abstract

The invention relates to a method and an arrangement for sorting randomly distributed refuse sacks containing different types of refuse sorted at source. Each refuse sack has a predetermined means of identification (R, G, B, O, GR) for each type of refuse sorted at source. In the sorting, the refuse sacks are transported for them to be identified in successive sorting stations and separated so that refuse sacks containing a predetermined type of refuse are sorted out at the sorting station intended for this purpose. In the method according to the invention, in at least one sorting station (10a, 10b, 10c; 14a, 14b, 14c) refuse sacks containing another predetermined type of refuse (R, G, B, O, GR) and provided with associated means of identification are identified and separated.

Description

The present invention relates to a method and an arrangement for the sorting of refuse sacks according to the pre-characterising clause of claim 1 and claim 4 respectively.
A number of different types of refuse occur in present-day communities. Economic and environmental handling of this refuse requires that it be sorted at source and thereafter transported to a sorting plant, for example, where the various fractions of the refuse sorted at source are sorted out for further processing according to the content of each fraction. It is important that each separated fraction containing refuse sorted at source be unadulterated. It is therefore essential that the refuse be correctly sorted at source and that the refuse sorted at source be sorted with as few errors as possible. Furthermore the investment and operating costs, for example, of arrangements for the separation of refuse sorted at source must be minimised. For example, the total energy consumption expended in refuse handling should not exceed that recovered from the sorted material or saved in a recycling system.
SE 507 257 (corresponding to WO-A-96/22512 ), for example, discloses a method of the aforementioned type. According to the method each refuse sack is assigned a predetermined means of identification, such as colour coding, for each refuse fraction, by means of which sacks are sorted. The refuse sacks are transported along a conveyor and are sorted by successively identifying and separating each refuse sack having a predetermined means of identification. SE 517 667 (corresponding to WO-A-03/039773 ) discloses a method of sorting for identifying sacks having a means of identification, but in contrast to the aforementioned method it is refuse sacks not having a predetermined means of identification that are separated out. In the sorting of refuse sacks provided with means of identification, there is a general desire to achieve a greater number of unadulterated fractions of refuse sacks, low energy consumption and low costs.
The object of the present invention is to provide a method that is improved in the aforementioned respects.
This object is achieved by the features specified in the characterising part of claim 1.
A further object of the invention is to provide an arrangement for performing the method according to the invention. This is achieved by an arrangement having the characteristics specified in claim 4.
The invention affords lower sorting-related costs and lower energy consumption. Furthermore, the sorting can be performed with few errors, which is important in obtaining unadulterated fractions, which is in turn important for processable fractions, as in the manufacture of biogas, composts and in other material recycling.
The invention will be explained in more detail here with reference to the following examples and the drawing attached, in which Fig. 1 in a schematic plan view from above shows an example of an arrangement for carrying out the sorting of two selected fractions of refuse sacks according to a known method and Fig. 2 similarly shows an example of an arrangement for carrying out sortings of two selected fractions of refuse sacks according to the present invention with the same degree of adulteration of the residual fraction and essentially the same capacity. Like Figs. 1 and 2, Figs. 3 and 4 show two comparative examples of the sorting of five selected fractions of refuse sacks according to a known method and according to the present invention, it being possible here also to carry out the sorting with the same degree of adulteration of the residual fraction and essentially the same capacity.
In an example of the sorting of two different colour-coded, randomly distributed fractions of refuse sacks shown in Fig. 1, these are placed at respective feed inputs 2a, 2b, 2c in a sorting plant, generally denoted by 1, with three sorting channels working in parallel in order to achieve the required sorting capacity, before then being transported on conveyors 3a, 3b, 3c arranged in series one after the other with a certain interval between individual sacks along each conveyor, to be identified at successively arranged sorting stations 4a-9a, 4b-9b and 4c-9c in order to separate red (R) and green (G) colour-coded sacks. The sacks provided with red (R) colour coding are identified and separated at the first three sorting stations 4a-6a, 4b-6b, 4c-6c and thereafter the sacks provided with green (G) colour coding are identified and separated at the three succeeding sorting stations 7a-9a, 7b-9b, 7c-9c. Separating sacks identifiable by the same colour at multiple succeeding sorting stations in this way naturally increases the capacity but primarily improves the unadulterated nature of the unseparated residual fraction, that is to say the sacks which have not been identified at any earlier sorting station. As stated, it is also possible to use multiple parallel sorting conveyors.
In the sorting performed according to the invention of two differently colour-coded, randomly distributed fractions of refuse sacks illustrated in Fig. 2, these are placed and transported in a similar way to that in the example above. The sacks provided with red (R) colour coding are identified and separated at the first two sorting stations 4a, 5a, 5b, 4b, 5b, 4c, 5c and thereafter the sacks provided with green (G) colour coding are identified and separated at the two succeeding sorting stations 7a, 8a, 7b, 8b, 7c, 8c. At a final sorting station both sacks with red (R) and green (G) colour coding are identified and separated in order to finally transport the separated sacks back to the feed input for renewed sorting as indicated by the conveyor belt 11. By sorting in this way a considerable improvement in the degree of adulteration of the residual fraction is achieved using fewer sorting stations than in the comparative example described above.
In order to further explain the advantages of the invention, the sorting of five differently colour-coded, randomly distributed refuse sacks containing different refuse fractions according to a known method and according to the method of the invention will be demonstrated with reference to Figs. 3 and 4. As has been explained in connection with Fig. 1, the refuse sacks are placed and transported on three parallel sorting conveyors 3a, 3b, 3c each having the sorting stations 4a-4c, 5a-5c, 7a-7c, 8a-8c, 11a-11c, 12a-12c, 13a-13c. Here the sacks provided with red (R), green (G), blue (B) orange (O) and grey (GR) colour coding are identified and separated in such a way that on each sorting conveyor 3a-3c the sacks provided with red (R) colour coding are separated from the other sacks at the first two sorting stations 4a-4c, 5a-5c, and sacks provided with green (G) colour coding are then separated at the two succeeding sorting stations 7a-7c, 8a-8c. Refuse sacks with blue (B), orange (O) or grey (GR) colour coding are identified and separated at the three succeeding sorting stations 11a-11-c, 12a-12c, 13a-13c. In this example, therefore, 21 sorting stations are needed.
In a sorting according to the invention of five differently colour-coded, randomly distributed refuse sacks the refuse sacks are placed and transported as illustrated in Fig. 4. The first four sorting stations 4a-4c, 5a-5c, 7a-7c, 8a-8c produce a separation of sacks provided with red (R) and green (G) colour coding. In a final sorting station (14a-14c) for each conveyor 3a-3c sacks provided with blue (B), orange (O) or grey (GR) colour coding are simultaneously identified and separated onto yet another sorting conveyor 15. Along this are three successively arranged sorting stations 16, 17, 18 in which sacks provided with blue (B), orange (O) or grey (GR) colour coding are identified and separated. The residual fraction from this conveyor is transported back to the inlet feed (2a, 2b, 2c) for renewed sorting. With this method according to the invention for sorting the five different fractions, the degree of adulteration achieved corresponds to that obtained in the example of the prior art, but is achieved with a smaller number of sorting stations, that is, in this example, 18 stations.
It will also be appreciated that the person skilled in the art is capable of selecting variants of sorting stations and combinations thereof, and of selecting the number and location of sorting conveyors with suitable sorting stations according to requirements.

Claims

Method of sorting randomly distributed refuse sacks containing different types of refuse sorted at source, each refuse sack having a means of identification (R, G, B; O, GR) for each type of refuse sorted at source and the sorting involving transport of the refuse sacks for them to be identified in successive sorting stations and separated so that refuse sacks having a predetermined means of identification for each sorting station are sorted out at the sorting station intended for this purpose, characterised in that in at least one sorting station (10a, 10b,10c; 14a, 14b, 14c) at least two means of identification (R, G; B, O, GR) predetermined for the sorting station are selectively identified and the corresponding refuse sacks separated, each of these having any of the selectively identified means of identification.
Method according to Claim 1, characterised in that refuse sacks which have been transported and undergone a successive sorting without being separated, are transported back for renewed sorting.
Method according to Claim 1 or 2, characterised in that a predetermined colour is used as means of identification for each type of refuse.
Arrangement for the sorting of refuse sacks comprising a transporting arrangement designed to transport randomly distributed refuse sacks containing different types of refuse sorted at source, each refuse sack having a means of identification (R, G; B, O, GR) for the type of refuse in the sack, a number of successively arranged sorting stations each comprising a sensor selectively sensitive to the respective means of identification and designed to emit a signal when a refuse sack passes which has a means of identification predetermined for the sensor and to which the sensor is sensitive, and separating elements designed, in response to a signal from the sensor, to undertake separation of the refuse sack in question from the transporting arrangement, characterised in that the sensing arrangement in at least one sorting station is sensitive to at least one further predetermined means of identification (R, G, B, O, GR) on refuse sacks containing another type of refuse.