A waste detection assembly

Abstract

A waste detection assembly (1) having a detection module (10) that comprises an excitation coil (31, 33) and a plurality of sensing units (13) comprising a sensing coil (35, 37) encircling a coil axis (A) The excitation coil envelops a plurality of coil axes (A).

Description

Technical Field

[0001] The field of the present invention relates to material recovery and recycling from waste. In particular, the invention concerns detection and classification of metal items in a flow of waste, such as batteries or gas containers. Background Art

[0002] Several solutions exist for detection and recovery of valuable materials from waste. Some solutions use colour recognition, such as for sorting plastic bags with waste that has been pre-sorted by the consumers.

[0003] The type discussed herein use magnetic fields to detect metallic items. A valuable type of detectable waste is batteries. Batteries contain valuable materials, such as lithium. Moreover, detection of batteries reduces fire incidents in waste disposal plants since batteries often ignite adjacent items in the waste due to shortcircuiting.

[0004] The article “ Classification of Non-ferrous Metals Using Magnetic Induction Spectroscope (O’Toole et al., 2017) discusses a solution wherein a plurality of excitation coils is used to generate primary magnetic fields that induce eddy currents in metallic objects. These eddy currents will induce a secondary magnetic field that is detected by number of sensing coils. The excitation coils and the sensing coils are arranged immediately below a conveyor belt, on which the detected items are transported.

[0005] Patent application publication EP1009049A2 discloses a solution for classifying and recovering used batteries using magnetic fields with a plurality of frequencies. By comparing the sensed secondary magnetic field to pre-stored profiles, batteries can be sorted according to battery type. Summary of invention

[0006] There is disclosed a waste detection assembly having a detection module that comprises an excitation coil. The detection module further comprises a plurality of sensing units having a sensing coil encircling a coil axis. The excitation coil envelops a plurality of coil axes.

[0007] The excitation coil is a magnetic excitation coil. In other words, it is suited for inducing a magnetic field by flowing electric current through it.

[0008] The detection module can comprise an upper and a lower excitation coil. Furthermore, the sensing units can comprise an upper and a lower sensing coil. The upper and lower sensing coils can be wound in opposite direction and envelop a common coil axis.

[0009] There is further disclosed a waste detection assembly having a plurality of detection modules which comprise an excitation coil, and a sensing unit comprising a sensing coil encircling a coil axis. Several excitation coils or several sensing coils comprise a coil portion extending parallel to and adjacent to a coil portion of adjacent excitation coils or sensing coils, respectively.

[0010] By having excitation or sensing coils extending parallel to and adjacent other coils, one can make the magnetic fields of these currents cancel each other out along the said adjacent and parallel parts of the coil. Thus, if for instance the excitation coils are arranged in such manner, several adjacently arranged excitation coils can together form a resulting larger excitation coil. This will be discussed in detail further below.

[0011] In some embodiments, the waste detection assembly can comprise a plurality of detection modules with excitation coils enveloping a plurality of coil axes of the sensing coils of the sensing units. Moreover, the plurality of excitation coils can comprise a coil portion extending parallel to and adjacent to a coil portion of adjacent excitation coils.

[0012] The excitation coil of the one or more detection modules can advantageously have a polygonal shape. This makes it easy to arrange one or more rows of detection modules in a systematic fashion, with the parallel coil portions adjacent to each other. For instance, the polygonal shape can be quadratic, rectangular, parallelogram, or trapezoid shape.

[0013] The waste detection assembly can comprise a plurality of identical detection modules arranged in at least two adjacent and parallel rows.

[0014] Arranging the detection modules in systematic rows, preferably with identical detection modules, makes it easy to adapt the overall size of the waste detection assembly according to need. Typically, the width of a waste conveyor belt may govern the needed size of the waste detection assembly.

[0015] Moreover, of for instance one sensing unit is malfunctioning, one can replace one single detection module.

[0016] Another advantage of using said detection modules with a plurality of sensing units is that one can connect and disconnect several coils (sensing coils and excitation coils) simultaneously with a multi-pin contact. This enables a swift installation of the waste detection assembly.

[0017] In some embodiments, the one or more detection modules can comprise a module structure supporting the excitation coil. The one or more detection modules can further comprise a mounting plate that supports a printed circuit board (PCB) and which is arranged between the PCB and the module structure. The PCB can govern electric current flown through the excitation coil and may receive electric current detected with the one or more sensing coils.

[0018] The module structure can for instance be box-shaped, with vertical walls that supports the excitation coils. It may be with or without a “box bottom”.

[0019] The mounting plate can comprise a junction arrangement. The junction arrangement can facilitate easy connection and disconnection when installing or replacing a detection module.

[0020] In some embodiments where the waste detection assembly according comprises a plurality of detection modules, it can have two rows of detection modules. It can further have two end detection modules arranged at opposite ends of the two respective rows. Examples of this is presented further below. The circumference of an excitation coil of the end detection module is less than the circumference of the excitation coil of the detection module.

[0021] By using the end detection modules, one achieves a displacement of the detection modules of the two rows. This enables that the sensing units are distributed along the extension of the rows, without two sensing units being located at the same position (along the direction of the rows).

[0022] In typical embodiments, the waste detection assembly further comprises a waste-transporting conveyor belt, wherein the one or more detection module(s) is / are arranged below the conveyor belt. In other embodiments, the one or more detection module(s) can be arranged above the conveyor belt.

[0023] In embodiments where the waste detection assembly comprises a printed circuit board (PCB), the PCB can comprise a control unit, excitation circuitry connected to the excitation coil(s), detection circuitry connected to the sensing coil(s), and an analyzing processing unit connected to the detection circuitry. Detailed description of the invention

[0024] While various features of the invention have been presented in general terms above, a more detailed and non-limiting example of embodiment will be presented in the following with reference to the drawings, in which Fig. 1 is a schematic view of a waste detection assembly arranged below a wastetransporting conveyor belt; Fig. 2 is a perspective view of an embodiment of a detection module comprising several sensing units; Fig. 3 is a schematic cross-section view of the detection module shown in Fig. 2; Fig. 4 is a schematic cross-section view through one of the sensing units shown in Fig. 3; Fig. 5 is a schematic top view illustrating the distribution of detection modules arranged in two parallel and adjacent rows; Fig. 6 is a perspective view of the detection module distribution shown in Fig. 5; Fig. 7 to Fig. 9 are top views of alternative detection module configurations; Fig. 10 is a top view illustrating a resulting or effective coil resulting from arranging several coils with coil portions parallel to and adjacent to each other; Fig. 11 is a schematic top view illustrating a further possible detection module distribution; and Fig. 12 is a schematic cross-section side view of another embodiment of a detection module.

[0025] Fig. 1 is a schematic side-view that illustrates an application of a waste detection assembly 1. The waste detection assembly 1 is located below the upper part of a waste conveyor belt 3 that transports different type of waste 5. Among the waste 5 there are batteries 7 that can be detected by the waste detection assembly 1. The batteries 7 can of course be of different types and in different conditions.

[0026] As will be discussed in further detail below, the waste detection assembly 1 is configured to detect metal-containing items, including discarded gas containers, batteries, and other objects.

[0027] Shown in the side-view of Fig. 1 are two detection modules 10. Fig. 2 depicts a perspective view of one detection module 10. The detection module 10 comprises a module structure 11. In the shown embodiment the module structure 11 is shaped like a rectangular box. The module structure 11 have walls 11a. Inside the module structure 11 there is arranged a plurality (eight in this embodiment) of sensing units 13. The sensing units 13 will be discussed in more detail further below.

[0028] The module structure 11 of the detection module 10 comprises an upper coil groove 15 and a lower coil groove 17. The upper and lower coil grooves 15, 17 are, in the shown embodiment, configured as horizontally extending grooves embedded in the walls 11 a of the module structure 11. The upper and lower coil grooves 15,17 will, as will also be discussed below, receive coils for generating a primary magnetic field.

[0029] The module structure 11 is supported on a lower horizontal part 19a of a mounting plate 19. The mounting plate 19 comprises the lower horizontal part 19a, an upper horizontal part 19b, and a vertical part 19c that joins the lower and upper horizontal parts 19a, 19b.

[0030] A printed circuit board (PCB) 21 is attached to the vertical part 19c, such that the vertical part 19c is between the PCB 21 and the module structure 11. The mounting plate 19 provides in this manner shielding for the PCB 21. Moreover, it further provides cooling function for the PCB 21.

[0031] Furthermore, an electric junction arrangement 23a is arranged below a junction arrangement lid 23. The electric junction arrangement 23a is supported by the upper horizontal part 19b.

[0032] The upper horizontal part 19b comprises a first handling recess 25a and an oppositely arranged second handling recess 25b. The first and second handling recesses 25a, 25b are configured for easy handling of the detection module 10, such as by gripping with a thumb and middle finger.

[0033] The dimensions of the module structure 11 include length (L), width (W) and height (H), wherein these dimensions can typically be within the following ranges: L=10-30 cm; W=5-20 cm; H=7-20 cm.

[0034] Also attached to the mounting plate 19 is a cable guide arrangement 27. The cable guide arrangement 27 is attached to the vertical part 19c of the mounting plate 19. An electric cable 29 is shown extending between the cable guide arrangement 27 and the electric junction arrangement 23a.

[0035] Fig. 3 is a schematic cross section side-view of the detection module 10 shown in Fig. 2. An upper excitation coil 31 is arranged in the upper coil groove 15 and a lower excitation coil 33 is arranged in the lower coil groove 17. The upper and lower excitation coils 31,33 are connected and wound in the same direction. This means that when electric current is run through them from a current supply, they will induce respective magnetic fields in the same direction.

[0036] Also shown in Fig. 3 are the sensing units 13, of which only four out of eight are shown. An enlarged cross section view through one sensing unit 13 is shown in Fig. 4. It comprises an upper sensing coil 35 and a lower sensing coil 37. The upper and lower sensing coils 35, 37 are interconnected and wound in opposite directions.

[0037] Furthermore, an upper core 39 and a lower core 41 are arranged such that they are encircled by the upper and lower sensing coils 35, 37, respectively. The upper and lower cores 39, 41 can typically be ferrite cores.

[0038] When used for detecting metal-containing items on the waste conveyor belt 3, the primary magnetic field is generated by flowing alternating electric current through the upper and lower excitation coils 31,33. If a metal-containing item is present, an eddy current will be induced in it, which further will induce a secondary magnetic field. The secondary magnetic field will be sensed by one or more of the sensing units 13, as it will generate current in the upper and lower sensing coils 35, 37.

[0039] By analyzing the detected secondary magnetic field, one can determine the location of the metal-containing item, such as a battery. Furthermore, one may identify the type of battery or other metallic item, such as a disposed gas container. To enable such analysis, the frequency of the primary magnetic field can be varied.

[0040] Reference is again made to Fig. 3. Coil axes A, of which two are shown in Fig. 3, extend through the upper and lower sensing coils 35, 37 of the sensing units 13. The upper and lower excitation coils 31,33 hence, in the shown embodiment, encircle a plurality of coil axes A (eight coil axes A in the present example). Notably, while the upper and lower excitation coils 31,33 are arranged at the same level along the coil axes A as the upper and lower sensing coils 35, 37, they could also be displaced along the coil axes A (as shown with the example in Fig. 12).

[0041] Fig. 5 is a schematic top view of a detection module assembly 100, comprising a plurality of assembled detection modules 10. Fig. 6 depicts the same detection module assembly 100, however shown without the sensing units 13.

[0042] As appears from Fig. 5 and Fig. 6, the detection module assembly 100 has an elongated configuration. In the shown embodiments, the module assembly 100 has two rows of detection modules 10. Furthermore, the plurality of sensing units 13, being part of the detection modules 10, form four rows along the longitudinal direction. When in use below the conveyor belt 3, as shown in Fig. 1, the longitudinal direction of the rows will be crosswise to the movement of the waste 5.

[0043] Referring to Fig. 5, the sensing units 13 are advantageously distributed with a mutual distance along the longitudinal direction. To enable such a distribution while also obtaining a square-shaped overall configuration of the detection module assembly 100, there are arranged two end detection modules 10a. The end detection modules 10a have a configuration similar to the detection modules 10 but comprise fewer sensing units 13. In the shown embodiment, the end detection modules 10a each have two sensing units 13.

[0044] Fig. 7 depicts another configuration of the detection module assembly 100. This configuration is similar to the one shown in Fig. 5 and Fig. 6. However, instead of the rectangular configuration of the module structures 11, the module structures 11 have a parallelogram shape.

[0045] Fig. 8 is another example of a detection module assembly 100, wherein the module structures 11 have a triangular shape. The sensing units 13 have been omitted from the illustration. Another possible shape is for instance trapezoid shape.

[0046] Common for the configurations shown in Fig. 5 to Fig. 8 is that the module structures 11 of the detection modules 10 have a polygonal shape. Contrary to this, the embodiment shown in Fig. 9 has a different, not polygonal shape, including curved walls of the module structure 11.

[0047] Notably, all the shown embodiments involve walls of the module structures 11 that are adjacent and parallel to walls of neighbouring module structures 11.

[0048] This enables some possibilities for the generation of the primary magnetic field.

[0049] Fig. 10 depicts an example of how the plurality of detection modules 10, with the upper and lower excitation coils 31,33, are used to produce the primary magnetic field. The embodiment shown in Fig. 10 corresponds to the embodiment shown in Fig. 5 and Fig. 6. The inserted arrows in Fig. 10 represent the direction of current flowing through the upper and lower excitation coils 31,33. Since the currents through the respective coils are synchronized and thus flow in the same direction (counterclockwise at the instant shown in Fig. 10), two oppositely flowing currents at two adjacent walls of the module structure 11 will cancel each other out. This occurs at coil portions 31 a that are arranged parallel to and adjacent to coil portions 31 a of neighbouring excitation coils 31,33. As a result, the generated primary magnetic field will be as if the coils extended around the entire detection module assembly 100. This is indicated with the thick line in Fig. 10.

[0050] By having the larger resulting or effective coil, the near field component of the primary magnetic field will fall off slower and thus reach further through non-conductive components of the waste 5 (such as paper-stacks), compared to having several smaller coils with a mutual distance to each other. The effective measurement range or detection range is thus increased. Furthermore, one maintains the advantage of a small coil in terms of manufacturability. Also, one allows for flexibility of shape for the assembled large coil, such as when the width of conveyors varies for different waste facilities. [0051 ] As shown in Fig. 10, there are two parallel rows of detection modules 10. Hence, one may for instance generate a primary magnetic field only with one of the two rows, such that the field is generated with a thinner resulting or effective coil configuration.

[0052] Fig. 11 illustrates a solution wherein the detection modules 10 have only one sensing unit 13 within the respective excitation coil or excitation coils 31,33. Similar to the end detection modules 10a discussed above, the detection module assembly 100 shown in Fig. 11 have two end modules 110a. However, the end modules 110a are not provided with any sensing unit 13. Instead, they are merely used to complete the overall or resulting shape of the excitation coil.

[0053] In Fig. 11, as in the previously discussed embodiments, the coil axes A (not shown) of the sensing coils 35, 37 are arranged within the excitation coils 31,33. Moreover, the excitation coils 31,33 envelop a larger area than the sensing coils 35, 37.

[0054] Fig. 12 depicts a schematic cross-section view of a detection module 10 that could be used in the configuration shown in Fig. 11. Notably, the detection module 10 has only one excitation coil 131 and only one sensing coil 135. Moreover, the excitation coil 131 and sensing coil 135 are mutually displaced along the coil axis A.

[0055] In an alternative embodiment, one could have the excitation coils 31,33, 131 encircling a smaller area than the sensing coils 35, 37, 135, with the coil axes A of the respective excitation coils 31,33, 131 being encircled by the sensing coils 35, 37.

Claims

1. A waste detection assembly (1) having a detection module (10) that comprises- an excitation coil (31,33);- a plurality of sensing units (13) comprising a sensing coil (35, 37) encircling a coil axis (A);wherein the excitation coil (31,33) envelops a plurality of coil axes (A).

2. A waste detection assembly (1) having a plurality of detection modules (10) which comprise- an excitation coil (31,33);- a sensing unit (13) comprising a sensing coil (35, 37) encircling a coil axis (A);wherein several excitation coils (31,33) or several sensing coils (35, 37) comprise a coil portion (31a) extending parallel to and adjacent to a coil portion (31a) of adjacent excitation coils (31,33) or sensing coils (35, 37), respectively.

3. A waste detection assembly (1) according to claim 1 and claim 2.

4. A waste detection assembly (1) according to one of the preceding claims, wherein the excitation coil (31,33) of the one or more detection modules (10) exhibits a polygonal shape.

5. A waste detection assembly (1) according to claim 2 or according to claim 2 and any other preceding claim, wherein it comprises a plurality of identical detection modules (10) arranged in one row, or two or more adjacent and parallel rows.

6. A waste detection assembly (1) according to any one of the preceding claims, wherein the detection module(s) comprise(s)- a module structure (11) supporting the excitation coil (31,33);- a mounting plate (19) supporting a printed circuit board (21) and arranged between the printed circuit board (21) and the module structure (11), whereinthe printed circuit board (21) controls electric current flown through the excitation coil (31,33) and receives electric current detected with the sensing coil (35, 37).

7. A waste detection assembly (1) according to claim 6, wherein the mounting plate (19) comprises a junction arrangement (23a).

8. A waste detection assembly according to claim 2 or according to claim 2 and any one of the preceding claims, comprising two rows of detection modules (10) and two end detection modules (10a) arranged at opposite ends of the two respective rows, wherein the circumference of an excitation coil of the end detection module (10a) is less than the circumference of the excitation coil (31, 33) of the detection module (10).

9. A waste detection assembly (1) according to any one of the preceding claims, further comprising a waste-transporting conveyor belt (3), and- wherein the detection module(s) (10) is / are arranged below the conveyor belt (3); or- wherein the detection module(s) (10) is / are arranged above the conveyor belt (3).

10. A waste detection assembly according to any one of the preceding claims, further comprising one or more printed circuit boards (21) comprising - a control unit,- excitation circuitry connected to the excitation coil(s),- detection circuitry connected to the sensing coil(s),- an analyzing processing unit connected to the detection circuitry.

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