DEVICE FOR THE SORTING OF WASTE BAGS

Abstract: A device for sorting differently coloured refuse bags (8) which are presented in random order distribution, the refuse bags of different colours containing different types of waste sorted at the source. The device comprises at least one conveyor belt (1) which is designed to convey bags arranged in rows one behind the other past sorting stations (2, 3, 4) arranged at intervals along said conveyor belt, and designed to identify and separate predetermined types of waste from the conveyor. The device is characterised in that it comprises at least one sorting station (2, 3, 4), in that each sorting station includes a first sensor (5) designed to detect and emit an output signal when refuse bags (8) which have at least one predetermined colour approach the sorting station. Each sorting station further contains a position-sensitive second sensor (6) which is designed to detect when the refuse bag (8) passes a predetermined position at the sorting station (2, 3, 4). The first and the second sensors (5, 6) are designed to actuate a member (7) for removing the bag from the conveyor belt.

Description: Device for the sorting of waste bags. The present invention relates to a device for sorting differently coloured refuse bags which are presented in random order distribution, the refuse bags of different colours containing different types of refuse sorted at the source, comprising at least one conveyor belt designed to convey bags arranged in rows with a space between each, past sorting stations arranged at intervals along said conveyor belt, and designed to identify and separate predetermined types of refuse from the conveyor. Industrial and household waste constitutes an ever increasing burden on the environment. The content in substances harmful to the environment results in a drastic increase of the demands made on the handling and treatment of waste. The large volumes of waste also cause problems of resource management. The re-use and recovery of materials from waste needs to be increased. For the refuse which, consequently, has to be dealt with, technology and systems for environment-friendly handling, as well as for subsequent treatment, have to be developed. SUBSTITUTESHEET A crucial requirement for an environment-friendly resource-saving handling of waste is that it should be sorted at the source. Accordingly, there must be developed a rational collection procedure for the various types of refuse in which said refuse is sorted. With respect to source sorting of household waste, there are at present five different main groups: refuse harmful to the environment, recoverable paper, glass, organic waste and other types, which can be separated. This procedure is usually described as sorting into five categories. It can be envisaged that in a not too distant future the number of categories will unfortunately increase when the need arises for sorting refuse into various sub-groups. It is therefore important that a household waste sorting arrangement should be devised for many different types of refuse, and that the number of types of waste that is sorted should be expanded as the need arises. A device of the type first mentioned hereinabove is known from, eg., SE-A 8901046-6. This document relates to a device for sorting refuse in which various types of refuse are separated by being placed in coloured bags or bags with colour markings. An identification member is used to 2 identify the bags. Mounted after the identification member is a separating member which is used to push the bag away from the conveyor belt. However, this device can be used only for the sorting of two so-called fractions and, therefore, in many cases it is inadequate for the sorting of source-sorted waste. The aim of the present invention is to provide a device able to separate a plurality of different fractions of refuse for subsequent treatment in different installations. This aim is achieved according to the invention in that the device comprises at least two or more sorting stations arranged in succession, in that each sorting station comprises a first sensor designed to detect and to emit an output signal when refuse bags of at least one predetermined colour approach the sorting station, in that every sorting station further contains a position-sensitive second sensor which is designed to detect when the refuse bag passes a predetermined position at the sorting station, as well as in that the first and second sensors are designed to actuate a member for removing the bag from the conveyor belt. According to a particular characteristic of the invention each first sensor in a sorting station i. is designed to be pre-set for detection of a colour or shade within the visible colour spectrum, and also first sensors in different sorting stations are designed to detect different colours or shades within the visible spectrum. According to a further particular characteristic of the invention said bag-removing member consists of a compressed air nozzle which is designed to be activated at a predetermined moment after a signal has been received from both the first and second sensors. According to another particular characteristic of the invention said first sensor includes a colour sensitive CCD array with an analogue and/or digital video system which has a field of vision through which the respective refuse bags pass, and which has a lens which is out of focus in such a way that a diffuse image is received of the refuse bag. In accordance with a last particular characteristic of the invention the refuse bags are conveyed along the conveyor belt at intervals which exceed the length of half a bag, The invention will be described hereinbelow in more detail with reference to the attached drawings wherein Fig. 1 is a diagrammatic plan view showing a device of the invention seen from above with a sorting station; Fig. 2 is a plan view of the sorting station of Fig. 1 seen from the side. In the drawing 1 denotes a conveyor belt by means of which refuse bags 8 can be conveyed towards the right of the drawing, as shown by arrows. This presupposes that, when the refuse bags 8 are placed on the belt 1, this is effected in such a way that two bags are prevented from coming close together. So that the waste sorting device may work without problems, there must be a distance between bags of at least 0.5 m. Along the belt, a succession of identical sorting stations 2, 3, 4 are arranged so that out of the random distribution of refuse bags, bags of one or more predetermined colours are sorted out. The refuse bags are made preferably of coloured plastic or paper bags. Each sorting station 2, 3, 4 contains at least two optical sensors 5, 6 connected with a steering gear and a separating member 7. Every separating member 7 contains preferably one compressed air nozzle, directed transversely to the conveyor belt 1, which communicates with a source of compressed air situated outside the installation. To use compressed air for moving the refuse bags is advantageous, as in this way it can be prevented that sorting might be hindered by refuse remains left on the belt. Naturally, it is also possible to use some type or other of mechanical drive with a drive member operating across the conveyor belt, for example electrically driven cylinders. The first sensor in each sorting station is sensitive to one or more predetermined colours, and the sensors in the various sorting stations are sensitive to colours which differ from those that are detected by the first sensor. The sensor which is used in this connection is preferably a colour-sensitive CCD-array with analogue and/or digital video system, preferably a standard video camera, which is linked with electronic circuits suitable for the purpose. The output signal from the camera is evaluated in said circuits and when the predetermined colour is detected a signal is despatched to the steering gear. So that reflections from the refuse bags 8 may not bring about an undesirable sorting result, the video camera is preferably designed to detect a 1 diffuse image. This is achieved by setting the video camera lens out of focus. Detection with the aid of the above-mentioned video camera requires external illumination of the refuse bags. This illumination is preferably provided by sources of light mounted above the device. The second sensor in each sorting station 2, 3, 4 is designed to detect the moment when the refuse bag finds itself in a specific position in the sorting station. This sensor ensures that the refuse bag is actually situated in a position suitable for blowing off before the compressed air nozzle is activated, and it is desirable that any danger of an incorrect result, being the consequence of reflections from the refuse bags, be eliminated. When the refuse bags 8 pass a specific position at the sorting stations 2, 3, 4, another signal is despatched to the steering gear. The steering gear is designed so as, after both sensors in the station concerned, ie. sensors 5, 6, have emitted their signals which are in agreement for the elimination of incorrect signals, to activate the separation member 7 in such a way that, after a predetermined period, it moves the refuse bag 8 off the conveyor belt 1. If any of the signals from the two sensors deviates from the desired value, the refuse bag continues on along the conveyor belt. When the steering gear in a sorting station does not receive the predetermined signals, the refuse bags pass said sorting station. The refuse sorting device is designed so that the number of types of waste which have to pass through the device is greater by one type than the number of sorting stations. Consequently, the separating member 7 is not used for moving certain coloured bags off the conveyor belt 1 which, instead, continue on with the conveyor to its end, unaffected by the separation member. In this way it is possible to carry out the sorting of one type of waste in addition to the number that has been set by the number of sorting stations 2, 3, 4. The device of the invention operates in the following manner: The refuse bags 8 are placed manually or automatically on the conveyor belt, oriented in such a way that two or more refuse bags will not form a so-called agglomerate, i.e. heap up on the conveyor belt 1. The steering gear is connected 1 so that the sensors 5, 6 in a sorting station should indicate both the right colour and position for the bags to be driven off the belt as a result of the separation member 7 becoming activated and compressed air blowing refuse off the conveyor belt. In this procedure the blowing away takes place a certain time after the two sensors have emitted the output signal, and at the same time the resetting of the two sensors takes place so that new refuse bags can be accepted at the sorting station. If the right signals are not received from both sensors, the refuse bags are allowed to pass further along with the conveyor belt. In this procedure, the resetting of the two sensors takes place a certain time after the second sensor has indicated that the bag has passed a certain point in the sorting station. It is obvious that within the scope of the inventive concept, the device of the invention may be used for sorting waste of many different types; the sole limitation is the number of colours that can reliably be detected in the first sensor and the number of shades in which refuse bags can be manufactured. Both the first and the second sensor are identical for all sorting stations, the only difference being that the electronic circuit connected with every first sensor can be programmed to emit a certain output signal for a certain definite colour or shade within the visible spectrum. Preferably, the most commonly occurring type of waste is placed in the refuse bags which are to travel with the conveyor belt to its end.

Claims: Claims 1. A device for sorting differently coloured refuse bags (8) which are presented in random order distribution, the refuse bags of different colours containing different types of waste sorted at the source, comprising at least one conveyor belt (1) designed to convey bags arranged in rows with a space between each, past sorting stations (2, 3, 4) arranged at intervals along said conveyor belt and designed to identify and separate predetermined types of waste from the conveyor, characterised in that the device comprises at least two or more sorting stations (2, 3, 4) arranged in succession; in that each sorting station comprises a first sensor (5) designed to detect and to emit an output signal when refuse bags (8) of at least one predetermined colour approach the sorting station; in that every sorting station further contains a position- sensitive second sensor (6) which is designed to detect when the refuse bag (8) passes a predetermined position at the sorting station (2, 3, 4), as well as in that the first and second sensors (5, 6) are desired to actuate a member (7) for removing the bag from the conveyor belt. 2. A device according to claim 1, characterised in that each first sensor in a sorting station is designed to be pre-set for detection of a colour or shade within the visible colour spectrum, and in that first sensors in different sorting stations are designed to detect different colours or shades within the visible spectrum. 3. A device according to either claim 1 or claim 2, characterised in that said bag-removing member (7) consists of a compressed air nozzle which is designed to be activated at a predetermined moment after a signal has been received from both the first and second sensors. 4. A device according to any of the foregoing claims, characterised in that said first sensor (5) consists of a colour-sensitive CCD array with an analogue and/or digital video system, which has a field of vision through which the respective refuse bags (8) pass, and which has a lens which is out of focus in such a way that a diffuse image is received of the refuse bag. 5. A device according to any of the foregoing claims, characterised in that the refuse 11 bags are conveyed along the conveyor belt at intervals which exceed the length of half a bag. AMENDED CLAIMS [received by the International Bureau on 17 October 1995 (17.10.95); original claims 1-5 replaced by amended claims 1-3 (2 pages)] 1. A device for sorting differently coloured refuse bags (8) which are presented in random order distribution, the refuse bags of different colours containing different types of waste sorted at the source, comprising at least one conveyor belt (1) designed to convey bags arranged in rows with a space between each, past sorting stations (2, 3, 4) arranged at intervals along said conveyor belt and designed to identify and separate predetermined types of waste from the conveyor, c h a r a c t e r i z e d in that the device comprises at least two or more sorting stations (2, 3, 4) arranged in succession; in that each sorting station comprises a first sensor (5) designed to detect and to emit an output signal when refuse bags (8) of at least one predetermined colour approach the sorting station whereby each first sensor in a sorting station is designed to be pre-set for detection of a colour or shade within the visible colour spectrum, first sensors in different sorting stations being designed to detect different colours or shades within the visible spectrum and said first sensor (5) consisting of a colour-sensitive CCD array with an analogue and/or digital video system, which has a field of vision through which the respective refuse bags (8) pass, and which has a lens which is out of focus in such a way that a diffuse image is received of the refuse bag, in that every sorting station further contains a position-sensitive second sensor (6) which is designed to detect when the refuse bag (8) passes a predetermined position at the sorting station (2, 3, 4) , as well as in that the first and second sensors (5, 6) are desired to actuate a member (7) for removing the bag from the conveyor belt at a predetermined moment after a signal has been received from both the first and second sensors. A device according to claim 1, c h a r a c t e r ¬ i z e d in that said bag-removing member (7) consists of a compressed air nozzle. A device according to any of the foregoing claims, c h a r a c t e r i z e d in that the refuse bags are conveyed along the conveyor belt at intervals which exceed the length of half a bag. STATEMENT UNDER ARTICLE19 The object of the above amendment of the independent claims 1, 2 and 3 is to more clearly define the scope of the invention with respect to the Y category references WO93/06945 and W090/11142

Inventors: WAHLQUIST ANDERS, WAHLQUIST, ANDERS
Applicants: WAHLQUISTS VERKSTAEDER AB, AB WAHLQUISTS VERKSTAEDER
Application year: 1995
Main classification: B07C5
IPC codes: B07C5