Field of the invention

[0001] The present invention relates to a liberation and separation device for separating a

first fraction with particles having first sizes in a first size range,

second fraction with particles having second sizes in a second size range, comprising:

a driven rotor, having a substantially horizontal rotational axis and a plurality of rotor blades arranged for rotating around the rotational axis in a rotational direction, an infeed device for introducing the particle stream into the liberation and separation device,

a distribution area or device for distributing the particle stream from the infeed device towards the rotor in a substantially downwards particle inflow direction, to a particle contact area where the particle stream contacts the rotor blades.

Background of the invention

[0002] WO 2014/041246 A describes a generic method for sorting waste into different products according to their grain size and for storing and using different products according to their grain size, e.g. as an additive in the manufacture of cement, concrete, asphalt and/or a grouting material.

[0003] EP 0329865 A describes a particle separator which uses differences in kinetic energy to achieve separation. Particles of different size or density are accelerated by being placed on a belt or passed between pinch rollers so that they are all projected at the same speed.

[0004] WO 2012/150250 A describes a fractionating device for separating feedstock into at least one light material fraction and a heavy material fraction. [0005] US 2002/0175113 A describes a method and an apparatus for the sorting of chips. The chips, which have kinetic energy, are separated from each other on the basis of the form or the length of their flight curve which depends on their air resistance. The kinetic energy of the chips is generated by a mechanical ejecting device ejecting the chips or by means of a fan conveyor or by means of the wings of a blowing chipper.

[0006] Such liberation and separation devices are furthermore known from public prior use. [0007] The known devices known from public prior use may comprise a separation apparatus for separating from a particle stream with moist particles a first fraction with particles of a first group of dimensions and a second fraction with particles of a second group of dimensions, comprising an in-feed device for the particle stream and a rotatable drum with plates at its circumference. Each plate may have a radially extending hitting surface for hitting the particles (the impact of the plates on the particles causes 'liberation' of agglomerated particles and acceleration of the particles, which causes a ballistic trajectory). Receiving areas are provided for receiving the particles of both the first and the second fraction along with a conveyor for discharging the particles from the receiving areas.

[0008] A disadvantage of the known liberation and separation devices is that they offer little control of operational variables such as falling speed of particles falling towards the particle contact area or ballistic properties of the particles liberated by the rotor. Another disadvantage is that light particles, for instance dust particles, often do not reach the particle contact area and are thus 'missed' by the rotor blades due to an air shell surrounding the rotor. Yet another disadvantage of the known liberation and separation device is that dust can hardly be dealt with in an efficient manner.

[0009] It is therefore an object of the present invention to provide a liberation and separation device that offers more control of operational variables, especially improved control of ballistic properties of the liberated particles. Another object of the invention is to provide a liberation and separation device wherein virtually all particles reach the particle contact area. A further object of the invention is to provide a liberation and separation device that allows dust to be dealt in an efficient way.

Summary of the invention

[0010] Thereto, the liberation and separation device according to the invention is characterized in that the liberation and separation device comprises an airflow generator for, during use, generating an airflow towards the rotor in an air inflow direction substantially perpendicular to the particle inflow direction and the rotational axis, wherein in the particle contact area the rotational direction is aligned with the air inflow direction for creating a low pressure zone in the particle contact area.

[0011] By using the above airflow generator a low pressure zone is created in the particle contact area due to the so-called 'Magnus effect'. Because of the rotational direction of the rotor being aligned with the air inflow direction, the incoming airflow is accelerated in the particle contact area and, consequently, lower pressure results. This inventive use of the aforementioned Magnus effect allows increased control of operation variables. The falling speed of the particles, for instance, can be controlled by increasing or decreasing the rotational speed of the rotor and/or increasing or decreasing the air speed of the incoming air flow, to decrease, respectively increase, the static pressure in the particle contact area and thus the suction force exerted by the particle contact area on the falling particles. Due to the above, operational manageability of the liberation and separation device is greatly increased. [0012] Furthermore, due to such an increased suction force being exerted on the falling particles, virtually all particles (also light particles) will reach the particle contact area in order to be 'hit' by the rotor blades. This also allows dust to be dealt with in an efficient manner, as also dust particles (i.e. very light particles) will be drawn towards the particle contact area. A suction device can be installed, for instance, to suck the dust particles away from the particle contact area. In addition, the ballistic properties of the particles liberated by the rotor can be adapted in an advantageous manner. [0013] An embodiment relates to an aforementioned liberation and separation device, wherein the rotor has an open rotor design, comprising an open space between opposite rotor blades to allow particles from the particle stream to pass through the rotor. Especially very light particles, such as dust particles, can be advantageously sucked into the rotor, for example to be disposed of. In any case, the open rotor design allows even more operational variables to be changed for optimal operation of the liberation and separation device.

[0014] An embodiment relates to an aforementioned liberation and separation device, wherein a resulting deflected flow is created downstream of the rotor during use, wherein a suction device is arranged downstream of the rotor for removing dust particles from the deflected flow. The Magnus-effect creates a predictable flow downstream of the rotor, in the context of this patent application referred to as the resulting deflected flow. Especially very light particles, such as dust particles, are caught in this flow and flow along therewith. Due to the predictability of this flow, especially with respect to the very light particles present therein, a suction device can be advantageously arranged downstream of the rotor to remove dust particles from the deflected flow. [0015] An embodiment relates to an aforementioned liberation and separation device, comprising a suction device arranged near the rotor for providing a suction force in the open space to remove particles therefrom. This allows dust particles or very light particles to be dealt with immediately upon entry thereof into the open space of the rotor.

[0016] An embodiment relates to an aforementioned liberation and separation device, wherein a wing-like body is provided downstream of the rotor, having a first surface and a second, opposing surface converging towards a trailing edge, wherein the first and second surfaces diverge upstream towards the rotor to form a third, curved surface, the third surface with one end being connected to the first surface and with an opposing end connected to the second surface, wherein the third surface is tightly arranged along a part of a rotational circumference of the rotor, the curvature of the third surface being the same as the curvature of the rotational circumference of the rotor. The wing-like body creates an even larger suction force in the particle contact area, without necessitating the use of a larger diameter rotor.

[0017] An embodiment relates to an aforementioned liberation and separation device, comprising a first reception means, having a first receiving area arranged at a first receiving distance from the rotor, for receiving and discharging the first fraction of particles.

[0018] An embodiment relates to an aforementioned liberation and separation device, comprising a second reception means, having a second receiving area arranged at a second receiving distance from the rotor, for receiving and discharging the second fraction of particles, wherein the second receiving distance is larger than the first receiving distance. [0019] An embodiment relates to an aforementioned liberation and separation device, wherein the airflow generator is arranged at a same height as the rotor, the air inflow direction being substantially horizontal. The airflow itself thus interferes in a relatively minimal way with the hitting action of the rotor blades. Furthermore, in practice, a vertical wall of the liberation and separation device will often be present near the rotor. The airflow generator can be installed in or near this wall to conveniently transport air from the outside of the liberation and separation device to the inside thereof.

[0020] Another embodiment relates to an aforementioned liberation and separation device, comprising

a rotatable drum having a drum wall comprising a drum space, the drum being rotatable around a drum rotation axis, wherein, in a cross-section transversal to the drum rotation axis, the drum space comprises:

an outlet of the infeed device, being arranged for introducing the particle stream into the drum space during use, wherein, due to rotation of the drum in a rotational direction, a substantially oval particle stream is formed moving along a substantially oval particle trajectory inside the drum space, wherein a part of the oval particle stream contacts the drum wall, an outlet of an air blower device, being arranged for blowing air within the oval particle trajectory in a direction towards an upper part of the oval particle stream not contacting the drum wall, for blowing the particles of the first fraction outside from the oval particle stream to form a first fraction particle stream,

the rotor, being arranged outside of the oval particle stream and being arranged below the first fraction particle stream for receiving the first fraction particle stream in the particle contact area, wherein the rotational axis of the rotor is parallel to the drum rotation axis and the rotational direction of the rotor opposes the rotational direction of the drum, wherein in the particle contact area the particles of the first fraction particle stream are hit by the rotor blades in order to be propelled back into the oval particle stream,

the air flow generator, being positioned outside of the oval particle stream and being arranged for, during use, generating the airflow towards the upper part of the rotor in the air inflow direction for creating the low pressure zone in the particle contact area.

Advantageously, the relatively light particles of the first fraction particle stream can be propelled back into the oval particle stream by the rotor to reduce the particle size of particles in the oval particle stream (this is realized by the impact and abrasive action of the relatively lighter/smaller particles on the particles of the oval particle stream).

[0021] An embodiment relates to an aforementioned liberation and separation device, wherein the airflow generator is arranged for, during use, generating the airflow towards the upper part of the rotor in the air inflow direction by means of suction created in a downstream area of the rotor. In some cases, for example when space is tight, it can be more convenient to create an airflow over the rotor by means of suction, instead of by blowing air towards the rotor from an upstream airflow generator.

[0022] An embodiment relates to an aforementioned liberation and separation device, wherein above the rotor a funnel-shaped body is arranged having an upper end with a first inner diameter for receiving the first fraction particle stream and a lower end for discharging the first fraction particle stream with a second inner diameter, the first inner diameter being larger than the second inner diameter. Thus, a more condensed first fraction particle stream falls onto the rotor, allowing improved control.

[0023] An embodiment relates to an aforementioned liberation and separation device, wherein downstream of the rotor a flow guidance body is arranged, extending between the rotor and a drum wall area where the oval particle stream contacts the drum wall, an upper part of the flow guidance body being arranged for guiding a lower part of the oval particle stream from the rotor to the drum wall area. In this way, improved recirculation and centrifugation of particles is achieved inside the drum.

[0024] An embodiment relates to an aforementioned liberation and separation device, wherein the airflow generator is embodied to use the suction created in the downstream area of the rotor to suck away dust particles. By doing so, the suction has thee advantageous double use of creating both the airflow over the rotor as well as directly removing very light particles from the liberation and separation device.

Brief description of the drawings

[0025] Embodiments of a liberation and separation device according to the invention will by way of non-limiting example be described in detail with reference to the accompanying drawings. In the drawings:

[0026] Figure 1 shows a schematic side view of a first exemplary embodiment of a liberation and separation device according to the invention and

[0027] Figure 2 shows a schematic cross-section of a second exemplary embodiment of a liberation and separation device according to the invention.

Detailed description of the invention

[0028] Figure 1 shows a schematic side view of a first exemplary embodiment of a liberation and separation device 1 according to the invention. Figure 1 more specifically shows a liberation and separation device 1 for separating a first fraction 2 with particles having first sizes in a first size range, such as in the range of 0 - 5 mm, and a second fraction 3 with particles having second sizes in a second size range, such as larger than 5 mm, from a particle stream 8. Of course, these particle sizes are merely mentioned by way of example. Typically, the maximum size of the particles will be around 20 mm, due to the impact thereof on the rotor. The particle stream 8 may comprise a mix of materials with different densities. The device 1 will cause an 'asymmetrical' size separation in such cases. The liberation and separation device 1 comprises a driven rotor 4 having a substantially horizontal rotational axis and a plurality of rotor blades 5, such as two to twelve blades, for instance four, five or six blades, arranged for rotating around the rotational axis in a rotational direction 6. The rotor 4 may have an outer diameter of, for instance, 0,2 - 0,6 m, such as 0,5 m. The shape of the rotor blades 5, in a cross-sectional plane perpendicular to the rotational axis, may for instance be straight, i.e. plate-like, or curved, wherein the convex part of the blade is situated on the outside of the rotor. The liberation and separation device 1 furthermore comprises an infeed device 7, such as a reservoir or a conveyor belt, for introducing the particle stream 8 into the liberation and separation device 1. A distribution device or area 9, to be broadly interpreted as an arrangement that distributes the particle stream 8 towards the rotor 4, for distributing the particle stream 8 from the infeed device 7 towards the rotor 4 in a substantially downwards particle inflow direction 10. Preferably, the particle stream enters a free fall from the conveyor downwards to the rotor 4. The particle stream 8 then falls onto a particle contact area 11 where the particle stream 8 contacts the rotor blades 5. Preferably, an additional air blower 45 is arranged near the position where the particle stream 8 initiates the free fall. The air blower 45 blows in a downwards direction to selectively increase the speed of particles falling towards the rotor 4, i.e. provide some 'tail wind' . In general, the free fall trajectory can be divided into a zone wherein the free falling particle stream 8 is influenced by the Magnus-effect of the rotor 4, and a(n upper) zone, wherein this is not the case. The air blower 45 is arranged to influence the particle speed in the latter zone. Important to note in this respect is that the particle stream 8 thins out during the free fall towards the rotor 4. Without additional 'air support', smaller/lighter particles therein have a lower maximum falling speed with respect to the air stream than larger/heavier particles. This pattern of particle falling speeds can be influenced advantageously by adapting the 'tail wind' provided by the air blower and/or by adapting the Magnus-effect provided by the rotor 4. Lighter particles may thus fall 'deeper' into the rotor 4, implying lower speed, different angle with curved rotor blades 5. Lighter particles may even fall through the rotor 4, in case of an open rotor design. [0029] According to the invention, the liberation and separation device 1 comprises an airflow generator 12 for, during use, generating an airflow towards the rotor 4, preferably straight towards the rotational axis, in an air inflow direction 13. The air inflow direction 13 is substantially perpendicular to the particle inflow direction 10 and the rotational axis. In the particle contact area 11, the rotational direction is aligned with the air inflow direction 13 for creating a low pressure zone in the particle contact area 11 as part of the Magnus-effect sought after by the invention. After the particles of the particle stream 8 are 'hit' by the blades 5 of the rotor 4, a first fraction with finer/lighter particles as well as a second fraction with heavier/larger particles can be observed. However, in practice this distinction will be relatively hard to see, due to the first and second fractions fading into each other (i.e. a continuous distribution will occur).

[0030] As shown in figure 1, the rotor 4 may have an open rotor design with an open space 14 between opposite rotor blades 5 to allow particles from the particle stream 8 to pass/fall through the rotor 4. In case of moist particles mixes, the rotor 4 is preferably close, whereas in case of dry mixes the rotor may have the abovementioned open rotor design.

[0031] Due to the Magnus-effect, a resulting deflected flow 15 is created downstream of the rotor 4 during use. A suction device 16 is arranged downstream of the rotor 4 for removing dust particles from the deflected flow 15. Another suction device 17 can be arranged near the rotor 4 for providing a suction force in the open space 14 to remove very light particles therefrom. However, care should be exercised regarding the positioning of the suction device 16 with respect to the rotor 4, as the Magnus-effect provided by the rotor 4 must not be negatively influenced. In practice, such a suction device 16, 17 will only be used with relatively dry particle mixes. In case of moist particles the inlet of the suction device may clog up, which is highly undesirable. [0032] As shown in figure 1, a wing-like body 18 is provided downstream of the rotor 4. The wing-like body 18 has an upper, first surface 19 and a lower, second, opposing surface 20 converging towards a trailing edge 21. The first 19 and second surfaces 20 diverge upstream towards the rotor 4 to form a third, curved surface 22. The third surface 22 is connected with one end to the first surface 19 and with an opposing end connected to the second surface 20. The third surface 22 is tightly arranged along a part of a rotational circumference of the rotor 4, i.e. the curvature of the third surface 22 is the same as the curvature of the rotational circumference of the rotor 4. The wing-like body 18 positively influences the Magnus-effect of the rotor 4. Preferably, the wing- like body 18 is positioned in the so-called 'dead zone' behind the rotor 4.

[0033] A first reception means, such as a first container 46, is provided, having a first receiving area 24 arranged at a first receiving distance from the rotor 4, for receiving and discharging the first fraction of particles. Furthermore, a second reception means can be provided, for instance embodied by a second container 47, having a second receiving area 26, arranged at a second receiving distance from the rotor 4, for receiving and discharging the second fraction of particles. The second receiving distance is larger than the first receiving distance. [0034] The airflow generator 12 is arranged at a same height as the rotor, the air inflow direction 13 then being substantially horizontal. In a general sense, the airflow speed generated by the airflow generator 12 may be for instance in the range of 1-10 m/s, more preferably 2-6 m/s, even more preferably 4 m/s. Thus, a suction force is created on the falling particle stream 8 creating an evenly distributed falling speed pattern of the particle stream 8.

[0035] Figure 2 shows a schematic cross-section of a second exemplary embodiment of a liberation and separation device according to the invention. Figure 2 more specifically shows a liberation and separation device 1 comprising a rotatable drum 27 having a drum wall 28 comprising a drum space 29. As opposed to for instance the embodiment of figure 1, this variant allows the particle stream to be handled by the device 1 multiple times. The device 1 as depicted in figure 2 will primarily be used for the deagglomeration or deagglutination of brittle composite materials such as concrete. Another use of the device may be the polishing of particles or the removal of dust therefrom after mineral crushing. The dust removal allows the granulate to be handled later on without the hindrance, such as health risks, provided by fine particulate matter. [0036] The drum 27 is rotatable around a drum rotation axis. Preferably, the inside of the drum 27 has a helical shape or otherwise to allow transport of particles along the drum rotation axis (the drum rotation axis may for instance be tilted with respect to the horizontal). In a cross-section transversal to the drum rotation axis, the drum space 29 comprises an outlet 30 of the infeed device 7 (indicated schematically) being arranged for introducing the particle stream 8 into the drum space 29. Due to rotation of the drum 27, such as at a speed of about 20 RPM at a drum diameter of 2 m or a speed of 40 RPM at a drum diameter of 1 m, in a rotational direction 31, a substantially oval or elliptical particle stream 32 is formed moving along a substantially oval particle trajectory inside the drum space 29. A part 33 of the oval particle stream 32 contacts the drum wall 28 in the right part of figure 2. The drum 27 may have an inner diameter of for instance 1-3 m, such as 2 m.

[0037] An outlet 34 of an air blower device (not shown) is arranged within the oval particle trajectory 32 for blowing air in a direction towards an upper part 35 of the oval particle stream 32. Thus, the particles of the first fraction can be blown outside of the oval particle stream 32 to form a first fraction particle stream 36. The blowing speed at the outlet 34 may for example amount to 1-10 m/s, such as 2-8 m/s, for instance 4-6 m/s or 5 m/s. [0038] The rotor 4, as shown in the left part of figure 2, is arranged outside of the oval particle stream 32 and is arranged below the first fraction particle stream 36 for receiving the first fraction particle stream 36 in the particle contact area 11. The rotational axis of the rotor 4 is parallel to the drum rotation axis and the rotational direction 6 of the rotor opposes the rotational direction of the drum 31. In the particle contact area 11 the particles of the first fraction particle stream 36 are hit by the rotor blades 5 in order to be propelled back to the right into the oval particle stream 32. [0039] The air flow generator 12 is positioned outside of the oval particle stream 32 and is arranged for, during use, generating the airflow towards the upper part of the rotor 4 in the air inflow direction 13 for creating the low pressure zone in the particle contact area 11.

[0040] The airflow generator can simultaneously be arranged for generating the airflow towards the upper part of the rotor 4 in the air inflow direction 13 by means of suction created by a suction device 16 in a downstream area of the rotor 4 (as an alternative to enforcement or blowing). The airflow generator may be embodied to use the suction 16 created in the downstream area of the rotor 4 to suck away dust particles. Advantageously, the air blower devices 12 and 34 and the downstream suction device 16 may work together, i.e. the air blown out by the air blower device 34 can be sucked up again by the suction device 16. The air may then follow a schematically indicated trajectory as shown in the left of figure 2.

[0041] A funnel-shaped body 37 can be arranged above the rotor 4, having an upper end 38 with a first inner diameter for receiving the first fraction particle stream 36 and a lower end 39 for discharging the first fraction particle stream 36 with a second inner diameter, the first inner diameter being larger than the second inner diameter.

[0042] Downstream of the rotor 4 a flow guidance body 40 is arranged, extending between the rotor 4 and a drum wall area 41 where the oval particle stream 32 contacts the drum wall 28. An upper part of the flow guidance body 40 is arranged for guiding a lower part 42 of the oval particle stream 32 from the rotor 4 to the drum wall area 41. The flow guidance 40 body may be embodied as the wing-like body mentioned before. A suction generator 16' can also be positioned at a lower end of the flow guidance body 40, relatively close to the drum wall 28.

[0043] An airflow generator 12 (blower) is preferably placed at a same height as the rotor 4 to provide an airflow 13 towards the rotor. The airflow 13 can also be provided by the suction device 16 only. [0044] In general, the variant of the liberation and separation device 1 as shown in figure 2, uses the insight that fine particles during rotation of the drum are forced closer to the drum wall 28 than coarse particles. Therein, smaller particles have a lower 'critical speed' than larger ones. At the critical speed of the larger particles the smaller particles will stick to the drum wall 28.

[0045] Thus, the invention has been described by reference to the embodiments discussed above. It will be recognized that these embodiments are susceptible to various modifications and alternative forms well known to those of skill in the art without departing from the spirit and scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention.

Reference numerals

1. Liberation and separation device

2. First fraction

3. Second fraction

4. Rotor

5. Rotor blade

6. Rotational direction of rotor

7. Infeed device

8. Particle stream

9. Distribution device or area

10. Particle inflow direction

1 1. Particle contact area

12. Airflow generator

13. Air inflow direction

14. Open space

15. Resulting deflected flow

16. Downstream suction device (16')

17. -

18. Wing-like body

19. First surface

20. Second surface

21. Trailing edge

22. Third, curved surface

23. -

24. First receiving area

25. -

26. Second receiving area

27. Rotatable drum

28. Drum wall

29. Drum space

30. Outlet of the infeed device

31. Rotational direction of drum 32. Oval particle stream

33. Part of oval particle stream contacting the drum wall

34. Outlet of air blower device

35. Upper part of oval particle stream

36. First fraction particle stream

37. Funnel-shaped body

38. Upper end of funnel-shaped body

39. Lower end of funnel-shaped body

40. Flow-guidance body

41. Drum wall area where oval particle stream contacts wall

42. Lower part of oval particle stream

43.

44.

45. Additional airflow generator

46. First container

47. Second container