Liberation and separation device comprising a rotor and an airflow generator for creating a low pressure zone in a particle contact area of the rotor

Abstract

The invention relates to a liberation and separation device (1) for separating a first fraction (2) with particles having first sizes in a first size range, and a second fraction (3) with particles having second sizes in a second size range, comprising: a rotatable drum (27) having a drum wall (28) comprising a drum space (29), wherein the drum space comprises: an outlet (30) of an infeed device (7), being arranged for introducing a particle stream into the drum space, wherein, due to rotation of the drum, an oval particle stream (32) is formed inside the drum space, a rotor (4) with rotor blades (5), arranged outside of the oval particle stream and arranged below the first fraction particle stream for receiving the first fraction particle stream in a particle contact area (11), an air flow generator (12), positioned outside of the oval particle stream and arranged for generating an airflow towards an upper part of the rotor, characterized in that the outlet (30) of the infeed device (7) is positioned inside, or at, the oval particle stream (32).

Description

[0001] Liberation and separation device comprising a rotor and an airflow generator for creating a low pressure zone in a particle contact area of the rotor

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a liberation and separation device according to the preamble of claim 1.

[0004] BACKGROUND OF THE INVENTION

[0005] WO 2015 / 194949 A1 discloses such an aforementioned liberation and separation device for separating a first fraction with particles having first sizes in a first size range, and a second fraction with particles having second sizes in a second size range. 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).

[0006] 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 use of the aforementioned Magnus effect allows increased control of operational 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.

[0007] 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.

[0008] A disadvantage of the known liberation and separation device is that the liberation and separation efficiency of the device leaves room for even further improvement.

[0009] It is therefore an object of the present invention to provide a liberation and separation device providing increased liberation and separation efficiency.

[0010] SUMMARY OF THE INVENTION

[0011] Thereto, the liberation and separation device according to the invention is characterized in that, when viewed along the drum rotation axis, the outlet of the infeed device is positioned inside, or at the position of, the substantially oval particle stream.

[0012] By using the above arrangement of the outlet of the infeed device with respect to the oval particle stream, operational efficiency of the liberation and separation device is even further improved. Advantageously, use can be made of the acceleration abilities of the particle stream, in particular a particle stream that flows over a flow guidance body such as discussed hereafter.

[0013] An embodiment relates to an aforementioned liberation and separation device, comprising, in a cross-section transversal to the drum rotation axis, a suction device positioned inside the substantially oval particle stream for sucking away dust particles from the substantially oval particle stream. Preferably, a resulting deflected flow is created downstream of the rotor during use, wherein the suction device is effectively 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, the suction device can be advantageously arranged downstream of the rotor to remove dust particles from the deflected flow. Preferably, the suction device is placed at a position where maximum dust production occurs due to the bouncing of the particles against a drum wall area. Furthermore, in combination with a flow guidance body (discussed hereafter) a laminar flow can be created over the flow guidance body and the rotor. Moreover, it is preferred that no coarse particles are present at the position of the suction device. 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 towards the rotor with a second inner diameter, the first inner diameter being larger than the second inner diameter, wherein a longitudinal axis of the upper end extends at an angle with respect to the vertical, such that the upper end is angled towards the upper region of the drum space where the first fraction is separated from the oval particle stream. Thus, a more condensed first fraction particle stream is created immediately after the first fraction is separated from the oval particle stream in the upper region of the drum space, whereafter the first fraction particle stream falls onto the rotor, allowing improved control.

[0014] 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.

[0015] 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.

[0016] 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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:

[0018] Figure 1 shows a schematic cross-section of an exemplary embodiment of a liberation and separation device according to the invention.

[0019] DETAILED DESCRIPTION OF THE INVENTION

[0020] Figure 1 shows a schematic cross-section of an 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, and a second fraction 3 with particles having second sizes in a second size range, from a particle stream 8. The liberation and separation device 1 comprises a rotatable drum 27 having a drum wall 28 comprising a drum space 29. The particle stream 8 can thus be handled by the device 1 multiple times. The device 1 as depicted in Figure 1 will primarily be used for the deagglomeration or deagglutination of brittle composite materials such as concrete. Another use of the device 1 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. 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). When viewed along the drum rotation axis, such as in the cross-section transversal to the drum rotation axis, the drum space 29 comprises an outlet 30 of an infeed device 7 (indicated schematically) being arranged for introducing the particle stream 8 into the drum space 29.

[0021] According to the invention, when viewed along the drum rotation axis, the outlet 30 of the infeed device 7 is positioned inside, or at the position of, the substantially oval particle stream 32. Figure 1 shows the outlet 30 of the infeed device 7 being positioned at the position of the substantially oval particle stream 32. Due to rotation of the drum 27, 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 1. The drum 27 may have an inner diameter of for instance 1-3 m, such as 2 m.

[0022] The rotor 4, as shown in the left part of Figure 1 , 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 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. 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. A distribution area 9 is indicated, wherein the particle stream 8 is distributed towards the rotor 4 in a substantially downwards particle inflow direction 10.

[0023] 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. The air inflow direction 13 is substantially perpendicular to the particle inflow direction 10 and the rotational axis.

[0024] In the cross-section transversal to the drum rotation axis, a suction device 16 is positioned inside the substantially oval particle stream 32. The airflow generator 12 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 the suction device 16 in a downstream area of the rotor 4 (as an alternative to enforcement or blowing). The airflow generator 12 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 device 12 and the downstream suction device 16 may work together, i.e. the air blown out by the air blower device 12 can be sucked up again by the suction device 16.

[0025] 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 towards the rotor 4 with a second inner diameter, the first inner diameter being larger than the second inner diameter. A longitudinal axis F of the upper end 38 extends at an angle with respect to the vertical, such that the upper end 38 is angled towards the upper region 35 of the drum space 29 where the first fraction 2 is separated from the oval particle stream 32.

[0026] 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 a wing-like body. As mentioned before, the suction device 16 is preferably placed at a position where maximum dust production occurs due to the bouncing of particles of the particle stream 8 against the drum wall area 41. Furthermore, in combination with the flow guidance body 40 a laminar flow can be created over the flow guidance body 40 and the rotor 4. The outlet 30 of the infeed device 7 is preferably positioned near an upper end of the flow guidance body 40 to provide the particles with maximum acceleration. Moreover, it is preferred that no coarse particles are present at the position of the suction device 16.

[0027] The airflow generator 12 (blower) is preferably placed at a same height as the rotor 4 to provide the airflow 13 towards the rotor 4. The airflow 13 can also be provided by the suction device 16 only.

[0028] Thus, the insight is used 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.

[0029] 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, as defined in the appended claims. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention.

Claims

CLAIMS1. Liberation and separation device (1) for separating a first fraction (2) with particles having first sizes in a first size range, and a second fraction (3) with particles having second sizes in a second size range, comprising: a rotatable drum (27) having a drum wall (28) comprising a drum space (29), 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 (30) of an infeed device (7), being arranged for introducing a particle stream into the drum space during use, wherein, due to rotation of the drum in a rotational direction (31), a substantially oval particle stream (32) is formed moving along a substantially oval particle trajectory inside the drum space, wherein a part (33) of the oval particle stream contacts the drum wall, wherein, due to the rotation of the drum, the first fraction is separated from the oval particle stream in an upper region of the drum space to form a first fraction particle stream (36), a rotor (4) with rotor blades (5), 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 a particle contact area (11), wherein a rotational axis of the rotor is parallel to the drum rotation axis and a 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, an airflow generator (12), being positioned outside of the oval particle stream and being arranged for, during use, generating an airflow towards an upper part of the rotor in an air inflow direction (13) for creating a low pressure zone in the particle contact area due to the Magnus effect, the particle contact area therein exerting such a suction force on the falling particles of the first fraction particle stream (36) that virtually all particles will reach the particle contact area in order to be hit by the rotor blades, characterized in that, when viewed along the drum rotation axis, the outlet (30) of the infeed device (7) is positioned inside, or at the position of, the substantially oval particle stream (32).

2. Liberation and separation device (1) according to claim 1 , comprising, in the cross-section transversal to the drum rotation axis, a suction device (16) positioned inside the substantially oval particle stream (32) for sucking away dust particles from the substantially oval particle stream3. Liberation and separation device (1) according to claim 1 or 2, wherein above the rotor (4) a funnel-shaped body (37) is arranged having an upper end (38) with a first inner diameter for receiving the first fraction particle stream and a lower end (39) for discharging the first fraction particle stream towards the rotor with a second inner diameter, the first inner diameter being larger than the second inner diameter, wherein a longitudinal axis (F) of the upper end extends at an angle with respect to the vertical, such that the upper end is angled towards the upper region of the drum space where the first fraction (2) is separated from the oval particle stream (32).

4. Liberation and separation device (1) according to claim 1 , 2 or 3, wherein downstream of the rotor a flow guidance body (40) is arranged, extending between the rotor and a drum wall area (41) where the oval particle stream contacts the drum wall, an upper part of the flow guidance body being arranged for guiding a lower part (42) of the oval particle stream from the rotor to the drum wall area.

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