Method and apparatus for separating fractions from a material stream

Abstract

The present invention relates to a method and to an apparatus (1) by means of which a fraction having a high degree of purity can be separated from a heterogeneous material stream (3) using simple technical means. For this purpose, a housing (2) is arranged in noncomplex fashion above a conveying means (4) on which the material stream (3) to be separated lies. The required intake air is introduced into the interior of the housing (2) by means of adjustable nozzle outlet openings (19) and the air flow is directed onto at least one lateral housing wall (6). As a result of the Coanda effect, the air flow is fed along the housing wall (6) to the material stream (3) on the conveying means (4), as a result of which the material stream (3) is lifted and subsequently swirled. As a result of the swirling of the intake air flow and under the action of an exit air flow, a separating zone (20) is formed in which light fractions are extracted from the overall material stream (3) and discharged through the exit air device (9) at an optimum degree of separation of between 95 and 100%.

Description

[0001] METHOD AND DEVICE FOR SEPARATION OF FRACTIONS FROM A MACHINE STREAM

[0002] The present invention relates to a method and a device for separating fractions from a material stream with at least two material fractions, in particular to a system in which, using the Coander effect, the supply air quantities are guided along the walls of a housing in the direction of a material flow on a conveying device and thereby lift and agitate the material stream.

[0003] Similar processes and systems are known in the prior art from DE 10 2012 010 030 A1. This document discloses a device and a process in which a heterogeneous material stream is introduced into a housing by means of a conveying device and is thereby permeated by a gas flow, separating at least one fraction from the material stream. A disadvantage of the devices and processes known in the prior art is the generally high technical complexity, which results in relatively high manufacturing costs.Another device for separating recyclable waste is described in the prior art document DE 299 19 773 U1. This document describes a device for separating recyclable waste in which an airflow classifier is arranged at the end of a conveyor belt. This classifier essentially consists of a closed housing to which both an air injection nozzle and a suction line are connected. The air injection nozzle is oriented so that the airflow exiting it blows onto the material lying on the conveyor belt. This causes the light, large-area material particles to be agitated and picked up by the suction duct. They are then fed into a housing containing a rotary valve for separating the light, flat particles.

[0004] Furthermore, a device is known from DE 20 2008 001 933 U1 in the prior art, which essentially consists of a transport device at the end of which a classifying drum is arranged, the axis of rotation of which runs transversely to the transport direction. An air blowing device is arranged below the transport device between the end of the transport device and the classifying drum, which penetrates the falling material stream and thus carries along at least the lighter fractions of the material stream. The remaining fraction of the material stream then separates into medium-weight and heavy materials, with the medium-weight materials landing on the surface of the classifying drum and being transported away.As a result of the airflow emanating from the air injection device, the light and medium-weight material fractions are guided through a flow channel, at the end of which a collection device is arranged, thereby dividing the material flow into heavy, medium-weight and light material fractions.

[0005] The generally perceived disadvantages of the devices and methods known in the prior art are that, on the one hand, the separation capability of the systems between heavy, medium and light fractions of the material stream does not meet the requirements of the recycling industry, and on the other hand, the design and construction of such systems are technically relatively complex and therefore cost-intensive.

[0006] Therefore, the object of the present invention is to provide a method and a device that are able to overcome the disadvantages of the prior art and reduce the relatively high technical effort, wherein at least one sub-fraction with a high degree of purity is separated from a heterogeneous material stream in a technically uncomplicated housing with relatively small geometric dimensions.

[0007] This problem is solved by the characterizing features of the main claims. Further features essential to the invention can be found in the description and the dependent claims.

[0008] The inventive method for separating fractions of a material stream which is guided into a housing on a conveying means is characterized in that the supply air flow in the housing is directed onto a surface and supplied to the material flow by means of the Coander effect.

[0009] In this process, it is particularly advantageous that the supply air blown into the housing strikes a surface within the housing, along which the supply air is fed to the material flow on a conveying device. It is irrelevant whether the device for conveying the supply air is located on the top or side of the housing. What is important in this flow process is that the supply air flow is introduced to the material flow at a predetermined angle α along its longitudinal side, thereby lifting and agitating the material flow upwards. The airflow directed laterally towards the material flow, relative to its longitudinal axis, causes the material flow to be lifted, and, under the influence of an exhaust airflow, a separation zone is formed to separate at least one fraction from the material flow.Furthermore, it is advantageous that the individual fractions in the material flow are not only lifted but also swirled, and subsequently the lighter fractions in a separation zone are captured and drawn off by the resulting airflow within the separation zone.

[0010] Furthermore, it is advantageous that the primary supply air flow is generated by at least one nozzle with an adjustable nozzle outlet area, and that this accelerated supply air flow is directed towards a wall inside the housing, wherein this wall is preferably straight and flat.

[0011] It is advantageous that the at least one air supply device is arranged either on the top or on the side of the housing, whereby "on the side" refers to both the end faces and the side walls of the housing.

[0012] Another advantage is seen in the fact that the primary supply air generating nozzle outlet opening is designed to be elongated and the longitudinal axis of the nozzle outlet opening is arranged parallel to the conveying direction of the material flow.

[0013] It is also advantageous that the nozzle outlet opening generating the primary supply air is located essentially above the material flow.

[0014] Furthermore, it is advantageous that the flow velocities of both the supply air and the exhaust air are set so that a non-laminar flow area forms between the conveying medium and the exhaust air device as a separation zone, in which a separation between at least two fractions occurs.

[0015] The device according to the invention, built for the method according to the invention, for separating fractions from a material flow which is introduced into a housing on a conveying means, is characterized by at least one lateral supply air nozzle, the flow of which is directed towards a wall inside the housing, on which the supply air flow is directed towards the conveying means by utilizing the Coander effect and thereby lifts and swirls the material flow, wherein at least one exhaust air device captures the swirling, non-laminar supply air flow and thereby discharges at least one light fraction.

[0016] It is considered advantageous that the supply air flow within the housing is generated by at least two nozzle outlet openings located above the conveying medium.

[0017] Another advantage is that the exhaust air device is located in the upper part of the housing above the conveying medium between two supply air devices, which significantly reduces the geometric dimensions.

[0018] It is also advantageous that the longitudinal axis of the elongated nozzle outlet opening is arranged parallel to the conveying direction of the material flow.

[0019] Another advantage is that the position of the supply air nozzles and the exhaust air device relative to the conveying device is variably adjustable, with the distance d between the conveying medium and the lower edge of the nozzle outlet opening being variably adjustable.

[0020] Furthermore, it is advantageous that the slot width b of the nozzle outlet opening and thus the cross-sectional area is variably adjustable, which allows both the air volume and the flow velocity v to be regulated.

[0021] It is also advantageous that the cross-section of the nozzle outlet openings can be more angular, oval, or round. It is also advantageous that the outlet opening of the supply air nozzle is directed onto a flat surface within the housing, which is an integral part of the housing, thus eliminating the need for any additional walls or baffles within the housing to ensure the proper functioning of the process. This advantage is further enhanced by positioning the housing directly above the conveying medium carrying the material flow, and by arranging both the supply air and exhaust air systems on the top of the housing.

[0022] Further advantageous features and embodiments of the present invention can be found in the dependent claims, the description, and the drawings.

[0023] The invention will now be explained in more detail with reference to the drawings. It shows

[0024] Figure 1 shows a schematic perspective view of a plant with a device (1) for separating a material stream (3) with at least two fractions, with a conveying means (4) and at least one supply air device (8) and at least one exhaust air device (9) on a housing (2);

[0025] Figure 2 shows a schematic representation of a device (1) according to the invention in a housing (2) in which two supply air nozzles (19) and an exhaust air device (9) are arranged and the material flow (3) is introduced into the housing (2) by means of a conveying means (4);

[0026] Figure 3 shows a schematic representation of a device (1) according to the invention in a housing (2) in which two air supply nozzles (19) and an exhaust air device (9) are arranged and the air flows are symbolized by arrows; Figure 4 shows a schematic top view of the top of the housing (2) which is arranged above the conveying means (4).

[0027] Figure 5 shows a schematic representation of another embodiment of the device (1') according to the invention, in which an exhaust air device (9') is arranged on the top of the housing (2) and the supply air is supplied by an air supply device (8') on an end face of the housing (2).

[0028] Figure 1 shows a schematic perspective view of a system with a device 1 according to the invention in a housing 2. The system consists of a conveying element 4 above which the housing 2 is arranged. The material stream 3 transported on the conveying element 4 during operation (not shown here) generally comprises at least two fractions of a material mixture, such as is typical in waste management. A primarily heterogeneous material stream 3 is fed into the housing 2 via the conveying element 4 through a housing opening 5. The cross-section of the housing opening 5 can be varied and depends essentially on the accumulation of the material stream 3 and the supply air requirement of the device 1.

[0029] The housing 2 is arranged above the conveying element 4 and, in the present schematic embodiment, essentially consists of two straight, flat walls 6, which are connected to each other on both sides by a connecting element 7. In the upper region of the housing 2, two air supply units 8 are arranged in the immediate vicinity of the straight, flat side walls 6. In this embodiment, the air supply units 8 are elongated, and their function will be explained in more detail below. An exhaust air unit 9, which is also elongated, is arranged between the two air supply units 8. In this embodiment, the conveying element 4 is a conveyor belt driven by a motor 10. The at least two air supply units 8 arranged on the top of the housing 2 are capable of supplying the necessary adjustable volume of air for separating the individual fractions and lifting the individual fractions.The two air supply devices 8 extend over the entire length of the upper side of the housing 2.

[0030] Figure 2 shows a schematic cross-sectional view of a device 1 according to the invention in a housing 2, in the upper region of which two supply air devices 8 and an exhaust air device 9 are arranged, wherein the material flow 3 is introduced into the housing 2 by means of a conveying device 4. This view shows the basic cross-section perpendicular to the longitudinal axis of the housing 1 through the center of the supply air and exhaust air devices 8 and 9. The conveying device 4 is driven by the drive 10 and transports the material flow 3, which is not shown here, into the housing 2, which is arranged above the conveying device 4. The housing 2 consists of two side walls 6, which, for the sake of simplicity, are straight and flat in the present embodiment, but can also be curved or have other shapes.In the upper part of the housing 2, two supply air devices 8 are arranged laterally, introducing the required air volumes into the interior of the housing 2. An exhaust air device 9 is arranged between the two supply air devices 8, extracting the supplied air volumes. The capacity of this exhaust air device 9 is designed to be able to extract the supplied air volumes both through the supply air devices 8 and through the housing inlet opening 5, in order to ensure the proper aerodynamic functions within the housing. The connection nozzles 11, 12 of the supply air and exhaust air devices 8, 9 are funnel-shaped to increase or decrease the flow velocity of the supply air into the housing.

[0031] Between the two supply air devices 8 in the upper part of the housing 2, the exhaust air device 9 is arranged, extending over the entire length of the housing. The exhaust air device 9 consists of a funnel-shaped exhaust air nozzle 12, from which, in this drawing, a nozzle 13 extends downwards into the interior of the housing 2. A corresponding nozzle 14, which is slidably designed, is inserted into the end of the nozzle 13. The slidability of the inserted nozzle 14 serves to optimize the function and adjust the airflows within the housing, which are explained in more detail below.

[0032] At the end of the movable nozzle 14, two adjustable flaps 16 are hinged on both sides at the lower end. Their position can be continuously adjusted by means of a locking mechanism 17. The walls 6 of the housing 2, the walls of the exhaust nozzle 13, and the movable part 14 of this nozzle, in conjunction with the adjustable flaps 16, form two supply air ducts 18 within the housing 2, through which the supply air is introduced into the housing 2. The adjustable flaps 16 at the end of the movable nozzle 14 form a nozzle whose outlet openings 19 are variable due to their adjustable length and are set to optimize the separation of the material flow 3.

[0033] The nozzle outlet openings 19 of the supply air nozzles are elongated and arranged with their longitudinal axis parallel to the conveying direction of the conveying medium 4. The supply air flow is thus directed towards the walls 6 of the housing 2, after which the flow extends along the walls 6 due to the Coander effect.

[0034] Figure 3 shows a schematic cross-sectional view of the device 1 according to the invention in a housing 2 in which two supply air devices 8 and one exhaust air device 9 are arranged, with the directions of the airflows within the housing being symbolized by arrows. This representation illustrates the operating principle and the directions of the individual flows of the supplied and extracted air volumes within the housing 2. In the present embodiment, the supply air is introduced into the housing 2 by means of two supply air devices 8. The airflows introduced by the supply air devices 8, which are arranged laterally on both sides, are accelerated by the initially funnel-shaped design of the supply air devices 8 and the subsequent narrowing of the supply air channels 15, and are then directed into the channels 17 in the housing 2.

[0035] Due to the adjustable flap 16, whose opening angle can be mechanically / electronically controlled by means of an actuator (not shown here), the elongated nozzle outlet opening 19 is adjusted so that the flow is accelerated or decelerated as required and directed towards a wall, which in this embodiment is the inner side of the housing wall 6. Due to the physical coander effect, the airflow extends along this wall to the end of the inner wall in the direction of the conveying medium 4 and is guided there, where it meets the material flow 3 and lifts it. As a result of the convergence of the two supply air flows above the surface of the conveying medium 4, the material flow 3 is lifted, loosened, and swirled.By lifting the heterogeneous material stream 3 and through the suction action of the exhaust air device 9, a separation zone 20 forms below the end of the control flaps 16. In this zone, the lighter fractions, such as films, are extracted by the exhaust air device 9, separated from the other fractions, and discharged. The discharged light fraction is thus separated from the remaining heavier fractions by almost 99%, ensuring a high degree of purity of the separated light fractions as a result of this separation process. The heavier fractions of the material stream 3, with their higher density, do not reach the separation zone 20 and, due to gravity, fall back onto the conveying medium 4 after a short lift, where they are discharged.

[0036] The walls 6 of the housing 2 do not necessarily have to be flat, but can also be curved or formed in another technically sensible shape.

[0037] Figure 4 shows a schematic top view of the upper side of the housing 2, which is arranged above the conveying medium 4. On the conveying medium 4, the primary material stream 3 is introduced into the housing 2 through a housing opening 5 and undergoes at least one separation process there, in which the lighter fractions of the material stream 3 are sorted out, as described above, so that the remaining heavier fractions are discharged with the material stream 3' downstream of the device 1 in the conveying direction. Both the supply air devices 8 and the exhaust air device 9 are arranged on the upper side of the housing 2 and thus contribute, among other things, to the compact design of the entire system. The exhaust air device 9 is arranged between the two lateral supply air devices 8.Overall, both devices, the supply air devices 8 and the exhaust air device 9, are elongated, with the longitudinal axes of both devices 8,9 being parallel to the conveying direction of the material flow 3.

[0038] Figure 5 shows a schematic representation of another embodiment of the device T according to the invention, in which an exhaust air device 9 is arranged on the top of the housing 2 and the supply air is supplied through a supply air device 8' on an end face of the housing 2. In this embodiment, the supply air flows within the housing 2 are formed by separating one of the supply air flows. After the separation of one supply air flow from the supply air device 8', the two newly formed supply air flows are fed in channels (not shown) to a connecting element 22, in which the two air flows meet and are then fed longitudinally to the material flow, thereby lifting and swirling the material flow. The subsequent separation process of the individual fractions within the housing 2 has already been described above.The direction of material flow 3 is indicated by the arrowhead.

[0039] In summary, the present invention presents, on the one hand, a fluid-technically sophisticated method and, on the other hand, a technically simple design for a device 1 that can be easily adapted to any type of conveying medium, e.g., a screen, a vibrating trough, a ballistic separator, or a chute / slide, that transports a material stream whose individual fractions are to be separated from a heterogeneous material stream 3 with a high degree of purity. For this purpose, a housing 2 is arranged above a conveying medium 4 on which the material stream 3 to be separated rests. The required supply air is introduced into the interior of the housing 2 by means of adjustable nozzle outlet openings 19, and the airflow is directed against at least one lateral housing wall 6.As a result of the Coander effect, the airflow along the housing wall 6 is directed towards the material flow 3 on the conveying medium 4, causing the material flow 3 to rise and subsequently become swirled. Due to the swirling of the supply air flow and under the influence of an exhaust air flow, a separation zone 20 is formed in which lighter fractions are separated from the entire material flow 3 and discharged by the exhaust air device 9 with an optimal separation efficiency of between 95 and 100 percent. In both described embodiments of the present invention, a slight negative pressure prevails inside the housing; in other words, the output of the exhaust air device 9 is set slightly higher than the output(s) of the supply air device(s) 8, 8', resulting in pressure conditions π < pa, where π is the air pressure inside the housing and pa is the air pressure outside the housing 2.

Claims

PATENT CLAIMS 1. Method for separating fractions from a material flow (3) which is guided on a conveying means (3) into a housing (2), characterized in that the supply air flow in the housing (2) is directed onto a surface (6) and is supplied to the material flow (3) along the surface (6) by means of the Coander effect.

2. Method according to claim 1, characterized by introducing an air supply into the housing (2), which acts above the conveying means (4) on the material flow (3) in such a way that the material flow (3) is raised.

3. Method according to one of the preceding claims, characterized by at least one air supply device (8, 8') which is arranged either on the top or on the side of the housing (2).

4. Method according to one of the preceding claims, characterized in that a separation zone (20) is formed under the influence of an exhaust air flow for separating at least one fraction from the material flow (3).

5. Method according to one of the preceding claims, characterized in that the individual fractions in the material flow (3) are swirled during lifting and the light fractions in a separation zone (20) are captured and carried away by the resulting airflow within the separation zone (20).

6. Method according to one of the preceding claims, characterized in that the supply air flow is generated by at least one nozzle with a nozzle outlet opening (19) which is directed towards a wall (6), preferably a flat wall.

7. Method according to one of the preceding claims, characterized in that the nozzle outlet opening (19) generating the supply air is designed to be elongated and the longitudinal axes of the nozzle outlet opening (19) are arranged parallel to the conveying direction of the material flow (3).

8. Method according to one of the preceding claims, characterized in that the nozzle outlet opening (19) generating the supply air is arranged substantially above the material flow (3).

9. Method according to one of the preceding claims, characterized in that the flow velocity of both the supply air and the exhaust air is adjusted such that a non-laminar flow area is formed as a separation zone (20) between the conveying means (4) and the extraction device (9), in which a separation between at least two fractions takes place.

10. Device (1 ) for separating fractions from a material flow (3) which is guided on a conveying device (4) into a housing (2), characterized by a surface (6) which, by means of the Coander effect, directs the supply air flow within the housing (2) onto the material flow (3) on the conveying device (4).

11. Device according to one of the preceding claims, characterized in that the supply air flow is directed towards a wall (6) inside the housing (2) by means of the nozzle outlet opening (19) and the supply air flow is directed towards the conveying means (4) on which the material flow (3) lies, thereby lifting and swirling the material flow (3).

12. Device according to one of the preceding claims, characterized in that at least one exhaust air device (9) extracts the introduced turbulent, non-laminar flow and thereby discharges at least one fraction from the material flow (3).

13. Device according to one of the preceding claims, characterized in that the supply air is introduced into the housing (2) above the conveying means (4) and is directed along the wall (6) in the direction of the conveying means (4).

14. Device according to one of the preceding claims, characterized in that the supply air flow is formed by at least two nozzle outlet openings (19) which are arranged above the conveying means (4).

15. Device according to one of the preceding claims, characterized in that the exhaust air device (9) is arranged in the upper area of ​​the housing (2) above the conveying device (4) between two supply air devices (8).

16. Device according to one of the preceding claims, characterized in that the longitudinal axis of the elongated nozzle outlet opening (19) and the exhaust air The inlet opening (21) is arranged parallel to the conveying direction of the material flow (3).

17. Device according to one of the preceding claims, characterized in that the slot width (b) of the nozzle outlet opening (19) and thus the cross-sectional area is variably adjustable, whereby both the air volumes and the flow velocity (v) can be regulated.

18. Device according to one of the preceding claims, characterized in that the distance (d) between the conveying means (4) and the lower edge of the nozzle outlet opening (19) is variably adjustable.

19. Device according to one of the preceding claims, characterized in that the cross-section of the nozzle outlet openings (19) can be polygonal, oval or round.

20. Device (1 ) for separating fractions from a material flow (3) which is guided on a conveying device (4) into a housing (2), characterized by a nozzle whose outflow is directed towards a wall (6) which is arranged above the conveying means (4) on which a material flow (3) is introduced into the housing (2) and above the conveying means (4) at least one supply air device (8) and at least one exhaust air device (9) which discharges the quantities of air introduced into the housing (2).

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