WO1993006945A1

WO1993006945A1 - Arrangement for sorting waste sacks

Info

Publication number: WO1993006945A1
Application number: PCT/SE1992/000661
Authority: WO
Inventors: Lars Larsson
Original assignee: Ab Wahlquists Verkstäder
Priority date: 1991-10-07
Filing date: 1992-09-24
Publication date: 1993-04-15
Also published as: SE467394B; SE9102894D0; SE9102894L

Abstract

The invention relates to an arrangement for waste sacks. At least two kinds of optically identifiable sacks containing different categories of waste sorted at source occur with a random mutual distribution. The sacks arranged one after the other in a row are conveyed past devices for identifying sacks containing a predetermined category of waste. Separation devices controlled by a registration and control device interacting with the aforementioned identification devices sort sacks containing the predetermined category of waste. For each category of waste, other than the first, there are at least two mutually identical sorting stations arranged one after the other. Each station has two optical sensors positioned directly opposite one another to either side of the aforementioned transport device, for the simultaneous identification of one and the same waste sack. Separation is achieved by means of a double-acting compressed air cylinder without a piston rod arranged across the aforementioned transport device, to which cylinder there is operatively connected an ejector plate. From one of its end positions the plate describes an ejection movement in the direction of its other end position at a predetermined time after both the sensors in the associated station have identified a sack containing the predetermined category of waste.

Description

Arrangement for sorting waste sacks

The present invention relates to an arrangement for sorting waste sacks, of which at least two kinds of optically identifiable sacks containing different categories of waste sorted at source occur with a random mutual distribution, comprising transport devices by means of which the sacks arranged one after the other in a row are conveyed past identification devices so arranged as to identify sacks containing a predetermined category of waste, and separation devices positioned after the aforementioned identification devices and so arranged, when controlled by a registration and control device interacting with the aforementioned identification devices, as to sort waste sacks containing the predetermined category of waste.

Waste from industries and households represents an increasingly heavy load for the environment. The content of environmentally harmful substances means that the requirements for handling and processing the waste will increase drastically. The large volumes of waste also pose problems for resource management. There needs to be an increase in the reuse and recycling of materials from the waste. Technology and systems for the environmentally acceptable handling and final processing of the waste which finally requires to be dealt with must be developed.

A critical precondition for the environmentally acceptable and resource-saving handling of the waste is for this to be sorted at source. What is then required is the development of a rational collection method for the different categories of waste into which the waste is sorted.

A model has been developed for domestic waste, which calls for households to sort their waste into five different categories. Environmentally friendly waste

- Recyclable paper

- Glass

- Organic waste - Other waste

According to this model, the first three categories (fractions) of waste are taken to so-called local recycling stations, which are situated within walking distance of the home, from where it is then collected by the public cleansing department.

The present invention is concerned primarily with the collection and sorting system which has been designed for the last two categories of waste.

An arrangement of the kind described by way of introduction is previously disclosed through, for example, SE-A-890106- 6. This arrangement is relatively complex and space- demanding, however, partly because it contains a number of mutually interacting conveyor belts.

The object of the invention is, by utilizing the collection system which is already installed (waste chute, holding reservoir and disposal vehicle) in conjunction with an arrangement of simple and compact design, to be able to separate at least the aforementioned two fractions of organic waste and other waste for final processing in different plants.

This is achieved in accordance with the invention in that the arrangement comprises for each category of waste, other than the first, at least two mutually identical sorting stations arranged one after the other along the aforementioned transport device, each of which stations includes identification and separation devices, in that the aforementioned identification device at each station comprises two optical sensors positioned directly opposite one another to either side of the aforementioned transport device and so arranged at more or less the same time as to identify one and the same waste sack, and in that the aforementioned separation device consists of a double- acting compressed air cylinder without a piston rod arranged across the aforementioned transport device, to which cylinder there is operatively connected an ejector plate, which ejector plate is so arranged as to execute from one of its end positions an ejection movement in the direction of its other end position at a predetermined time after both the sensors in the associated station have identified a waste sack containing the predetermined category of waste, which means that sacks with the last- mentioned content are displaced from the aforementioned transport device in both directions across its direction of transport, whereas other sacks accompany the transport device as far as the next two mutually identical sorting stations or to its end.

The invention is described in more detail below with reference to the accompanying drawing, in which

Fig. 1 illustrates schematically as a plan view an arrangement in accordance with the invention viewed from above and with two mutually identical sorting stations; Fig. 2 is a plan view of the arrangement in accordance with Fig. 1 viewed from the side? and Fig. 3 shows the arrangement in accordance with Fig.

1 as a cross-section along A-A in Fig. 2.

It is assumed below that two categories of waste are placed inside waste sacks which differ in that they are white and black respectively, and that the identification devices are optical sensors sensitive to white. It is obvious that the waste sacks within the scope of the idea of invention may, as an alternative, be marked in some other optically identifiable manner. A person skilled in the art will also appreciate that the arrangement in accordance with the invention can be extended with further sorting stations arranged in pairs in order to be able to sort further categories of waste.

The designation 1 is used in the drawing for a transport device in the form of a conveyor belt, which runs over guide rollers 3 mounted in a frame 2, and by means of which waste sacks (not shown) can be transported in a direction towards the right in the drawing, as indicated by the arrows 4, 5. The arrow 4 is half black and half hatched, which symbolizes the presence of black and white waste sacks distributed in a mutually random fashion. The arrow 5 is completely black and represents only black waste sacks, which leave the belt 1 at its extreme right-hand end. The hatched arrows 6-9 pointing outwards from the belt must be taken to represent white waste sacks, which leave the belt cross-wise to its direction of transport, as described below. It is assumed that, when the waste sacks are placed on the belt, this is done in such a way that no two sacks are permitted to lie next to one another. Situated along the length of the belt are two mutually identical sorting stations I, II positioned one after the other and so arranged as to sort white sacks from the random distribution of white and black waste sacks.

Each of the sorting stations I, II comprises two optical sensors 2_τ, 13_x and 12_IZ, 13_α connected to a control device A and a separating device 14_r and 14^. Each separating device 14_ϊf 14_IX consists of a double-acting compressed air cylinder 14_Ia, 14_IIt. without a piston rod arranged across the conveyor belt 1, to the cylinder of which there is operatively connected an ejector plate 14^,, 14_IIb, the plane of which coincides with the direction of transport and which is so arranged as to be displaced between two end positions. Which of the end positions the ejector plate is occupying at any given time is indicated by means of limit switches 14_lc, 14_Id and 14_IIC, 14_IId connected to the control device 11. The control device 11 actuates a compressed air device 15, which in turn is connected at its outlet to the cylinders 14_Ia, 14_IIa. The control device 11 comprises a manually adjustable timer circuit and is so arranged as to cause the ejector plate 14_Ib, 14_nb via the compressed air device 15 to describe an ejection movement from its one end position to its other end position at a predetermined time after both sensors at the station in question, i.e. the sensors 12₁₇ 13_x or I2_π/ 13_n, have both identified a white waste sack. The black waste sacks continue along the conveyor belt 1 to its end unaffected by the ejector plates 14_Ib, 14_1Ib. These are preferably executed with lifting heels 16 so arranged as to lift the white waste sacks from the belt 1, thereby reducing the friction against it.

A single container 17, shown by a broken line in Fig. 1, is preferably positioned beneath the stations I and II, so that all the white waste sacks find their way into this container, whereas all the black waste sacks find their way into a container 18, shown by a broken line at the end of the conveyor belt 1.

The arrangement in accordance with the invention operates in the following way:

The waste sacks are placed manually or automatically on the belt 1 approximately at the point indicated by the arrow 4 and positioned so that two or more waste sacks do not lie side by side across the width of the conveyor belt 1. The control device 11 is connected in such a way, for example by means of an AND-gate circuit, that both photocells 12_Ir 13₃. must record a white waste sack in order for the waste sack to be ejected from the belt 1 by the ejector plate 14_Ib describing an ejection movement from one of its end positions to the other. The ejection movement in this case takes place a certain time after both the optical sensors 12_r and 13_x have identified the waste sack in question. This time corresponds to the transport time found by experiment for the sack to travel from identification to ejection.

In the event of a white waste sack not being ejected from the belt at station I, this will occur at station II, which operates in an entirely analogous fashion with station I.

Ejection takes place, as already mentioned, in such a way that the ejector plate 14_n, driven by the double-acting cylinder 14_ra moves from one of its end positions to the other. Switching takes place by means of the limit switches 14_IC, 14_Id in such a way that the air from the compressed air supply 15 is directed to that side of the cylinder piston which produces the desired ejection movement. This can take place either by electrical means, as shown in Fig. 1, whereby the limit switches are connected to the control device 11, or by pneumatic means, whereby the limit switches operate as pneumatic switches. connected to the compressed air supply 15, by means of which the compressed air supply is made to occur in such a way that the desired ejection movement is obtained.

It is obvious that the arrangement in accordance with the invention can be extended within the scope of the idea of invention in order to sort waste of three or four categories, for which purpose two or three pairs of sorting stations are required. The identification devices in each pair are identical and are sensitive to white or green or red light, whereas the separation devices are identical for all the sorting stations. The most commonly encountered category of waste should preferably be contained in black waste sacks, which continue along the conveyor belt to its end.

Claims

Patent Claims

l. Arrangement for sorting waste sacks, of which at least two kinds of optically identifiable sacks containing different categories of waste sorted at source occur with a random mutual distribution, comprising transport devices by means of which the sacks arranged one after the other in a row are conveyed past identification devices so arranged as to identify sacks containing a predetermined category of waste, and separation devices positioned after the aforementioned identification devices and so arranged, when controlled by a registration and control device interacting with the aforementioned identification devices, as to sort sacks containing the predetermined category of waste, characterized in that the arrangement comprises for each category of waste, other than the first, at least two mutually identical sorting stations (I, II) arranged one after the another along the aforementioned transport device, each of which stations includes identification and separation devices, in that the aforementioned identification device at each station comprises two optical sensors (12_I7 13_Z; 12_1If 13_XI) positioned directly opposite one another to either side of the aforementioned transport device and so arranged at more or less the same time as to identify one and the same waste sack, and in that the ^{^}aforementioned separation device consists of a double-acting compressed air cylinder (14_Ia; 14_IIa) without a piston rod arranged across the aforementioned transport device, to which cylinder there is operatively connected an ejector plate (14^,; 14_IIb) , which ejector plate is so arranged as to execute from one of its end positions an ejection movement in the direction of its other end position at a predetermined time after both the sensors (12_If

13_r; 12_n, 13_n) in the associated station (I, II) have identified a waste sack containing the predetermined category of waste, which means that sacks with the last-mentioned content are displaced from the aforementioned transport device (I) in both directions across its direction of transport, whereas other sacks accompany the transport device as far as the next two mutually identical sorting stations or to its end.

2. Arrangement in accordance with Patent Claim 1, characterized in that the ejector plate (14^,; 14_IIb) is executed on either side with lifting heels (16) intended to reduce the friction between the waste sack and the aforementioned transport device (l).

3. Arrangement in accordance with Patent Claim 1, characterized in that, at least beneath the aforementioned transport device in conjunction with each pair of sorting stations, a space is present enabling a second transport device or a container to be positioned across the aforementioned transport device.