Device and method for sorting bulk material

Abstract

The invention relates to a device and corresponding method for sorting bulk material, in particular pellets, comprising a vibration conveyor apparatus and a feed apparatus, which feeds bulk material to the vibration conveyor apparatus and is examined for defects using a detector apparatus. Bulk material identified as being non-defective is deposited in a first outlet and bulk material identified as being defective is shorted out and deposited in.

Claims

1. A device for sorting bulk material comprising: a vibration conveyor apparatus comprising a transparent window configured to allow passage of X-ray radiation; a feed apparatus which feeds bulk material to the vibration conveyor apparatus; a rotationally driven roller coupled to one end of the vibration conveyor apparatus and configured to impart a predetermined trajectory to the bulk material; a first outlet configured to receive the bulk material conveyed over the end of the vibration conveyor apparatus at the predetermined trajectory; a second outlet; at least one detector apparatus configured to examine the bulk material conveyed by the vibration conveyor apparatus for defects, the detector apparatus comprising, at least one X-ray detector apparatus comprising at least one X-ray radiation source and at least one X-ray sensor, wherein the at least one X-ray radiation source shines through the transparent window and the bulk material conveyed over the vibration conveyor apparatus, and wherein the at least one X-ray sensor detects the X-ray radiation shining through the bulk material and the transparent window; a first optical detection apparatus and a second optical detection apparatus, wherein the first optical detection apparatus is configured to examine the bulk material from a top side on the rotationally driven roller or after leaving the rotationally driven roller, and the second optical detection apparatus is configured to examine the bulk material from a bottom side when the bulk material is in free fall after leaving the rotationally driven roller; and a sorting apparatus configured to alter the predetermined trajectory of the bulk material identified as defective by the detector apparatus such that the bulk material may be deposited into the second outlet, wherein at least one of the first optical detection apparatus and the second optical detection apparatus is configured to operate in at least one of a visible wavelength range or an infrared wavelength range with at least one optical radiation source and at least one optical sensor.

2. The device of claim 1, wherein at least one of the at least one optical sensor and the at least one X-ray sensor comprises a high-speed sensor.

3. The device of claim 1, wherein at least one optical detector apparatus is configured to examine the bulk material in front of a non-illuminated dark background, and wherein a plane of focus of the at least one optical sensor lies in a same plane as the bulk material to be examined.

4. A device for sorting bulk material comprising: a vibration conveyor apparatus; a feed apparatus which feeds bulk material to the vibration conveyor apparatus; a rotationally driven roller coupled to one end of the vibration conveyor apparatus and configured to impart a predetermined trajectory to the bulk material, wherein the rotationally driven roller is at least partially comprised of a material transparent for X-ray radiation; a first outlet configured to receive the bulk material conveyed over the end of the vibration conveyor apparatus at the predetermined trajectory; a second outlet; at least one detector apparatus configured to examine the bulk material conveyed by the vibration conveyor apparatus for defects, the detector apparatus comprising, at least one X-ray detector apparatus comprising at least one X-ray radiation source and at least one X-ray sensor, wherein the at least one X-ray sensor is configured in a torque-proof manner within the rotationally driven roller or positioned below or above the rotationally driven roller, and wherein the at least one X-ray radiation source shines through the bulk material conveyed over the rotationally driven roller and the X-ray radiation shining through the bulk material is detected by the at least one X-ray sensor, a first optical detection apparatus and a second optical detection apparatus, wherein the first optical detection apparatus is configured to examine the bulk material from a top side on the rotationally driven roller or after leaving the rotationally driven roller, and the second optical detection apparatus is configured to examine the bulk material from a bottom side when the bulk material is in free fall after leaving the rotationally driven roller; and a sorting apparatus configured to alter the predetermined trajectory of the bulk material identified as defective by the detector apparatus such that the bulk material may be deposited into the second outlet, wherein at least one of the first optical detection apparatus and the second optical detection apparatus is configured to operate in at least one of a visible wavelength range or an infrared wavelength range with at least one optical radiation source and at least one optical sensor.

5. The device of claim 4, wherein at least the vibration conveyor apparatus is surrounded by a closed housing.

6. The device of claim 4, wherein the sorting apparatus comprises a blowout or suction apparatus configured to divert the bulk material identified as defective from the predetermined trajectory by blowing or suctioning such that the bulk material is deposited into the second outlet.

7. A device for sorting bulk material comprising: a vibration conveyor apparatus comprising a window transparent for X-ray radiation is disposed in a floor of the vibration conveyor apparatus; a feed apparatus configured to feed bulk material to the vibration conveyor apparatus; a curved section comprising a ramp that is coupled to one end of the vibration conveyor apparatus and configured to impart a predetermined trajectory to the bulk material; a first outlet configured to receive bulk material that is conveyed over an end of the vibration conveyor apparatus at the predetermined trajectory; a second outlet; at least one detector apparatus configured to examine the bulk material conveyed by the vibration conveyor apparatus for defects, the detector apparatus comprising, at least one X-ray detector apparatus comprising at least one X-ray radiation source and at least one X-ray sensor, wherein the at least one X-ray radiation source shines through the window transparent for X-ray radiation and the bulk material conveyed over the vibration conveyor apparatus, and wherein the at least one X-ray sensor detects the X-ray radiation shining through the bulk material and the window transparent for X-ray radiation, and at least one optical detector apparatus configured to operate in at least one of a visible wavelength range or in an infrared wavelength range with at least one optical radiation source and at least one optical sensor; and a sorting apparatus configured to alter the predetermined trajectory of bulk material identified as defective by the detector apparatus and conveyed over the end of the vibration conveyor apparatus such that the bulk material identified as defective falls into the second outlet.

8. The device of claim 7, wherein at least the vibration conveyor apparatus is surrounded by a closed housing.

9. The device of claim 7, wherein the detector apparatus includes a first optical detector apparatus and a second optical detector apparatus, the first optical detector apparatus is configured to examine the bulk material from a top side on the curved section, and the second optical detector apparatus is configured to examine the bulk material from a bottom side when the bulk material is in free fall after leaving the curved section.

10. The device of claim 7, wherein at least one optical detector apparatus is configured to examine the bulk material in front of a non-illuminated dark background, and wherein a plane of focus of the at least one optical sensor lies in a plane of the bulk material to be examined.

11. The device of claim 7, wherein the sorting apparatus comprises a blowout or suction apparatus configured to divert the bulk material identified as defective from the predetermined trajectory by blowing or suctioning such that the bulk material is deposited into the second outlet.

12. The device of claim 7, wherein the curved section is parabolic in shape.

13. A method for sorting bulk material comprising: feeding bulk material to a vibration conveyor apparatus, the vibration conveyor apparatus comprising a window transparent for X-ray radiation; conveying non-defective bulk material over one end of the vibration conveyor apparatus at a predetermined trajectory and into a first outlet; examining the bulk material for defects using an assembly comprising, at least one X-ray detector apparatus having at least one X-ray radiation source, at least one X-ray sensor, and a first and second optical detection apparatus including at least one optical radiation source and at least one optical sensor, the at least one X-ray radiation source shines through the bulk material conveyed over the vibration conveyor apparatus and through the window transparent for X-ray radiation and the at least one X-ray sensor detects the X-ray radiation shining through the bulk material and the window transparent for X-ray radiation, wherein the bulk material is examined by the first optical detection apparatus from a position above the bulk material and by the second optical detection apparatus from a bottom side when the bulk material is in free fall from the end of the vibration conveyor apparatus; and manipulating the predetermined trajectory of the bulk material identified as defective and conveyed over the end of the vibration conveyor apparatus such that the bulk material is deposited into a second outlet.

14. The method of claim 13, wherein the predetermined trajectory is imparted by a rotationally driven roller.

15. The method of claim 13, wherein the predetermined trajectory is imparted by a curved section.

16. The method of claim 13, wherein at least one of the first and the second optical detection apparatus examines the bulk material in front of a non-illuminated dark background, and wherein a plane of focus of the at least one optical sensor lies in a plane of the bulk material to be examined.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the invention are explained in greater detail below based on figures. They show schematically:

(2) FIG. 1 is a perspective view of a device according to the invention for sorting bulk material and

(3) FIG. 2 is a part of the device from FIG. 1 in an enlarged perspective view,

(4) FIG. 3 is the part of the device from FIG. 1 shown in FIG. 2 according to a second exemplary embodiment in an enlarged perspective view,

(5) FIG. 4 is a perspective view of a device according to the invention for sorting bulk material according to a further embodiment.

DETAILED DESCRIPTION OF THE INVENTION

(6) If not otherwise specified, the same reference numbers indicate the same objects in the figures. Reference number 10 in FIG. 1 shows a feed apparatus with a feed hopper for bulk material, plastic pellets in the shown example. Although the device according to the invention and the method according to the invention are explained below based on the sorting of plastic pellets, the sorting of any other bulk material is naturally also possible. Moreover, the device comprises a vibration conveyor apparatus 12 with a first vibration conveyor 14, a second vibration conveyor 16 connected to the first vibration conveyor 14 and a third vibration conveyor 18 connecting to the second vibration conveyor 16. The feed apparatus 10 feeds the plastic pellets to the first vibration conveyor 14. All vibration conveyors 14, 16, 18 can be driven in a vibrating manner, wherein the vibration conveyors 14, 16, 18 are individually controllable with respect to their vibration sequence and vibration amplitude. For this, a control and regulation apparatus not shown in the figure is provided, which controls overall the device according to the invention. FIG. 1 further shows that the three vibration conveyors 14, 16, 18 are arranged at different angles with respect to the horizontal. The first vibration conveyor 14 has a slight tilt with respect to the horizontal, the third conveyor 18 also has a slight tilt with respect to the horizontal and the second vibration conveyor 16 has the greatest tilt with respect to the horizontal. The vibration conveyors 14, 16, 18 are designed in a ramp-like manner, wherein the movement of the plastic pellets is restricted laterally by side walls of the vibrations conveyors 14, 16, 18.

(7) A wall 20 progressing transversely to the conveying direction of the bulk material is designed on the surface of the first vibration conveyor 14. It serves on one hand to distribute the plastic pellets leaving the opening of the feed hopper 10 onto the first vibration conveyor 14 evenly onto the vibration conveyor 14. Moreover, the wall 20 hold the pellets back from further movement as soon as the vibration conveyor 14 is stopped, i.e. no longer vibrates. On the first vibration conveyor 14, the movement of the pellets begins in the conveying direction. On the second vibration conveyor 16, increased kinetic energy is supplied to the pellets so that they are accelerated and separated in the conveying direction. On the surface of at least one vibration conveyor, for example of the second and/or third vibration conveyor 16, 18, one or a plurality of barriers (e.g., 42 on FIG. 2) progressing transversely to the conveying direction of the bulk material and preferably forming a wave profile or a triangular profile in cross-section is preferably formed. For one, these serve to homogenize the conveying speed of the pellets. They also give the pellets a vertical energy, which leads to the breakdown of the multiple layers of the pellets. Thus, after passing through the barrier(s), preferably of the wave profile or triangular profile of the barrier(s), the pellets are located in a single-layer jam arrangement. In this arrangement, they can be examined by an X-ray detector apparatus, of which an X-ray radiation source is shown with reference number 22 in FIG. 1. A window 24 transparent for X-ray radiation, here a Mylar window 24, is designed in the floor of the third vibration conveyor 18. The X-ray radiation source 22 emits X-ray radiation, which shines through (penetrates) the pellets conveyed over the window 24 and the window 24. An X-ray sensor shown schematically with reference number 26, which detects the X-ray radiation, is located below the window 24. In this case, it is an X-ray camera operating in TDI mode. The X-ray detector apparatus examines the pellets for contaminants in its interior. The measurement results are fed to an evaluation apparatus integrated into the control and regulation apparatus, which decides on this basis whether the examined pellets should be sorted out as defective. In the shown example, a cylindrical roller 28 rotationally driven around the cylinder axis progressing perpendicularly to the conveying direction of the pellets connects directly to the end of the third vibration conveyor 18. The pellets make their way from the third vibration conveyor 18 onto the rotating roller 28, are transported a short distance by it and are subsequently transferred with a defined speed in a defined trajectory. As long as they are not thereby manipulated, they fall into a first outlet for good pellets along the trajectory 31 indicated with A in FIG. 1. In the shown example, the roller 28 is turned slightly faster than the conveying speed of the pellets before hitting the roller 28 so that the pellets are accelerated slightly.

(8) FIG. 1 also shows with reference number 30 a first optical detector apparatus, which examines the pellets right after leaving the driven roller 28 from the top side. Reference number 32 shows a second optical detector apparatus, which examines the pellets in their trajectory from the bottom side after leaving the roller 28. Both optical detector apparatuses 30, 32 irradiate the pellets with diffuse light in front of a black background and have high-speed cameras as optical sensors, which are operated in TDI mode. The optical detector apparatuses 30, 32 examine the pellets for optical contaminants, in particular in the area of their surface. In turn, the measurements results are fed to the evaluation apparatus integrated into the control and regulation apparatus and the evaluation apparatus decides based on the measurement results whether the examined pellets should be sorted out as defective. If the evaluation apparatus detects pellets to be sorted out as defective based on the measurement results of one of the detector apparatuses 22, 26, 30, 32, a blowout apparatus shown with reference number 34 in FIG. 1 is triggered at a suitable point in time so that the pellets to be sorted out as defective are diverted from their trajectory into the trajectory 36 indicated with B in FIG. 1 and fall into a second outlet for bad pellets.

(9) In the enlarged partial representation in FIG. 2, reference number 38 shows the tilt angle ? of the third vibration conveyor 18 with respect to the horizontal. According to the invention, any tilt angle ? is generally conceivable. It is mainly determined by the conveyed amount and the bulk material to be checked. Reference number 40 simultaneously shows how the conveying speed v of the pellets on the vibration conveyor 18 is manipulated by the rotation of the roller to the new conveying speed v+Av. Moreover, for illustrative purposes, reference number 42 in FIG. 2 shows, instead of the window 24, as an example a barrier progressing transversely to the conveying direction of the pellets and preferably forming in cross-section a wave profile or a triangular profile.

(10) FIG. 3 shows the partial representation from FIG. 2 in a second exemplary embodiment. This exemplary embodiment mainly corresponds with the exemplary embodiment according to FIGS. 1 and 2. In contrast to the exemplary embodiment according to FIGS. 1 and 2, the exemplary embodiment according to FIG. 3 provides a bent section 44 connecting to the third vibration conveyor 18 instead of the rotationally driven roller 28. The bend of the bent section 44 can be for example parabolic or circular. The bent section 44 forms a ramp supporting the trajectory of the bulk material. It is understood that the other designs explained for FIGS. 1 and 2 are also applicable for the exemplary embodiment in FIG. 3.

(11) The device shown in FIG. 4 mainly corresponds with the device shown in FIG. 1. In contrast to the device from FIG. 1, the device shown in FIG. 4 has only one vibration conveyor 18, on the top side of which the bulk material is fed out of the feed apparatus 10, primarily over a feed slot 11. The vibration conveyor 18 in turn has a window 24 transparent for X-ray radiation, through which the X-ray radiation source 22 shines through the bulk material located on the vibration conveyor 18, wherein the X-ray radiation is detected by the X-ray sensor 26 arranged below the window 24, as already explained above. Furthermore, in the exemplary embodiment in FIG. 4, a guide cover 46 adapted to the surface bend of the roller 28, here a bent guide plate 46, is arranged at least in sections above the rotating roller 28. A bent gap, through which the bulk material is conveyed under reduction of the variation of the trajectories, exists between the guide plate 46 and the surface of the roller 28. Moreover, a slit-like guide channel 52 delimited by a first wall 48 and a second wall 50 is formed between the roller 28 and the blowout apparatus 34 for the bulk material falling from the roller 28 to the blowout apparatus 34. The first wall 48 is level and arranged in a vertical plane. The second wall 50 has a triangular cross-section such that the guide channel 52 in the trajectory of the bulk material first narrows in cross-section and then expands again. Moreover, in the exemplary embodiment in FIG. 4, reference number 54 shows a sorting channel, which is subdivided into two channel sectors arranged next to each other through a level blade 56 arranged in a vertical plane.

(12) Of course, it applies in turn that the designs shown in FIG. 4 can also be used for the exemplary embodiments explained based on FIGS. 1 to 3.