WO2011120536A1

WO2011120536A1 - Density separation device

Info

Publication number: WO2011120536A1
Application number: PCT/EP2010/002036
Authority: WO
Inventors: Kris Debaets; Hervé PACQUET; Rik Hoorelbeke
Original assignee: Fd-Process Bvba
Priority date: 2010-03-31
Filing date: 2010-03-31
Publication date: 2011-10-06

Abstract

The invention relates to a density separation device (1) comprising a rotatable barrel (2) and a combined feeding (3a) and discharging (3b) means in the form of a vibratory tray (3) running through the barrel from one open end (4) to the other open end (5). Said feeding means (3a) is provided with an opening (6) running at least partly along the length of the barrel through which the fed material can be dosed and spread into the rotatable barrel. Floating material is discharged by a constant overflow of liquid medium, while sunken material is uplifted by lifting means inside the rotating barrel onto the vibratory tray (3) and efficiently evacuated out of the barrel. The invention further relates to a method and to the use of such a device for separating solid material.

Description

DENSITY SEPARATION DEVICE

Technical field The invention relates to an improved density separation device for separating solid material particles in a float and a sink fraction by means of a liquid medium based on the principle of the specific density of said materials and said liquid.

The invention further relates to a method for separating heavy (sinking) and lighter (floating) material by means of a rotating barrel and dense medium liquid.

Background Art

A variety of dense medium separation devices have been proposed for this purpose, e.g. WO 2009103341 by Applicant.

EP2121193 A1 (Olivier) describes a dense medium separator subdivided into four functional zones: a distribution zone, a separation zone, a recovery zone and an evacuation zone. Solids and floats are separated by opposing currents in a bi- directional flow. The sinks are moved completely out of the separation zone before they are lifted out of the bath by means of a sinks mover disposed at the bottom of the separation zone that mechanically moves the sinks out of the separation zone and simunltaneously creates a counter-current. The lifting operation takes place in a location that is remote from the separation zone. Such a device however is complex in construction.

Other disadvantages that may occur when uplifting sunken material out of the bath is that the discharge or evacuation of the sunken material easily gets clogged up, resulting in loss of time and fewer throughput.

Disclosure of the invention

The purpose of the invention is therefore to provide a density separation device that does not get obstructed during processing. It is an object of the invention to increase the throughput rate, so that a much larger quantity of solid material can be processed, with a consequent increase in efficiency. Thereto the density separation device and methods of the invention provide means for a continuous high throughput of the material to be separated.

It is furthermore an object of the present invention to provide a device that is simple and cost-effective to manufacture, operate and maintain. Solid material ("solids") is fed into a rotatable dense medium barrel and separated into a float fraction ("floats") and a sink fraction ("sinks") by means of a specific and effective dosing of solids and evacuation of sinks. The dense medium device of the invention is workable in mono- or bi-directional flow.

In a first aspect the invention provides a density separation device (1) for separating solid material particles in a float and a sink fraction by means of a liquid medium, the specific gravity of said liquid medium being between the specific gravity of the particles of the float fraction and that of the particles of the sink fraction, the device comprising

a. a rotatable barrel (2) having two open ends (4,5), said barrel comprising means (11 ) mounted on the inner surface of the barrel (2) for uplifting material,

b. feeding means (3a) at one open end (4) for feeding the solid material into the barrel (2),

c. discharging means (3b) at the other open end (5) for discharging sunken material, and

d. an overflow zone (8) for evacuating the float fraction and the medium, whereby said feeding means (3a) and said discharging means (3b) are comprised in a vibratory tray (3) running through the barrel (2) from one open end (4) to the other open end (5), whereby said feeding means (3a) is provided with at least one opening (6) through which the solid material can be introduced into the barrel (2), and said discharging means evacuates uplifted sunken material out of the barrel. In a specific embodiment the vibratory tray (3) is a single-level tray comprising a feeding section (3a) provided from one end (4) of the barrel up to an opening (6) for disposing solid material into the barrel, and a discharging section (3b) provided from said opening (6) to the other end (5) of the barrel.

In another specific embodiment the vibratory tray (3) is a multi-level tray comprising a feeding section (3a) at a lower level provided from one end (4) of the barrel up to an opening (6) for disposing solid material into the barrel, and a discharging section (3b) at an upper level provided anywhere from the upper end (4) of the barrel to the other end (5) of the barrel.

The opening (6) for letting solid material fall through into the barrel preferably has a rectangular, trapezal or triangular shape, or any shape running along at least part of the length of the barrel. The shape of the opening is such that an optimal spread within the barrel is obtained. A better spread of material over the length of the barrel improves separation capacity and efficacy.

Providing material into the barrel starting from the upper end of the barrel has the advantage that the material can sink throughout the maximal length of the barrel.

The opening (6) may stretch anywhere from between the upper end (4) of the barrel to the other end (5) of the barrel, preferably in the first 1/2, 2/3 or 3/4 of the length of the barrel. The vibratory tray (3) is preferably positioned under a downwards angle_providing an extra gravital feeding and discharging of material, beside the movement caused by vibration. The vibratory tray (3) is vibrated by any means for causing such suitable vibrational movement of material. The open end (5) for providing an overflow of floats and medium is preferably conical. In another embodiment the discharge end may be straight as long as suitable for easy discharge. The means (11 ) mounted on the inner surface of the barrel (2) for uplifting and discharging sunken material onto the vibratory tray (3) is preferably one or more blades or a helical scroll. The sunken material could also be uplifted onto the vibratory tray by means of one or a combination of blades, helical scrolls, belts, augers, pumps, scraper chains, fully or partially perforated plates etc.

The barrel (2) may further be provided with axial plates or curtains (14) for preventing float material from moving into the lifting zone and being uplifted onto the discharging means (3b).

The rotatable barrel (2) may be positioned either horizontally along its longitudinal axis or inclined under an angle.

The separation device according to the invention may be provided in mono- or bi- directional mode, whereby the floats/medium and sinks fraction is discharged either at the same or at opposite ends.

In one embodiment, a monodirectional flow of medium is provided, whereby said overflow zone (8) for floats and medium and said discharging open end (5) for sinks are on the same ends (5) of the barrel. In another mebodiment, a bidirectional flow of medium is provided, whereby said overflow zone (8) for floats and medium and said discharging open end (5) for sinks are on opposite ends (4,5).

In a second aspect the invention provides a method for the selective separation of solid material, whereby the method comprises the steps of

feeding material to be separated into one open end (4) of a rotatable barrel (2) via the feeding section (3a) of a vibratory tray (3) running through the barrel (2),

dropping the material into the barrel (2) through an opening (6) in the vibratory tray (3),

separating the material into a float and a sink fraction by means of the specific gravity of said liquid medium and said fractions,

applying a constant flow (8) of liquid medium for evacuating the float fraction at one end (4,5) of the barrel (2), uplifting the sunken material onto the vibratory tray (3) by the means (1 1 ) mounted in the inner surface of the barrel (2) and the rotation of the barrel (2), and

evacuating said sunken material outside the barrel (2) at the other open end (5) via the discharge section (3b) of the vibratory tray (3).

The method may be provided in a mono- or bidirectional mode, whereby a flow of liquid medium is provided so that the overflow of float material (9) and medium is at the same or at an opposite end (5) of the barrel as the discharge end of sunken material (10).

In a third aspect the invention provides the use of a separating device (1 ) as described above for separating materials of different densities, e.g. vegetables, plastics, minerals and ASR (auto shredder residues).

Brief description of drawings

Figure 1 is a perspective view of a separating device according to the invention. Figure 2 is a longitudinal cross section of a separating device according to the invention.

Figure 3 is a radial cross section of a separating device according to the invention. Figure 4 is a schematic representation of a separating device according to the invention with a first embodiment of a vibratory tray.

Figure 5 is a schematic representation of a first embodiment of a vibratory tray according to the invention.

Figure 6 is a schematic representation of a separating device according to the invention with a second embodiment of a vibratory tray.

Figure 7 is a 3D representation of a second embodiment of a vibratory tray according to the invention.

References:

(1 ) separation device

(2) rotatable barrel

(3) vibratory tray: (3a) feeding section - (3b) discharging section (4) first open end

(5) second open end

(6) feeding opening into the barrel

(7) dense medium liquid

(8) overflow

(9) floats

(10) sinks

(11 ) blades

(12) transportation band

(13) container

(14) curtain or axial plates

(15) wheels

(16) collector plate

Modes for carrying out the invention

As shown in Figure 1 , the separation device (1 ) comprises a rotatable barrel (2) with a vibratory tray (3) running through the barrel from one open end (4) to the other open end (5). Solid material is fed onto the feeding section (3a) while sunken material is discharged via the discharge section (3b).

"Open end" means that the barrel is provided with means for having a vibratory tray (3) running through the barrel from one end to the other end of the barrel. Figures 2 and 4 illustrate a first embodiment of a feeding means (3a) provided with an opening (6) at the upper end of the barrel through which the fed material can fall into the rotatable barrel.

With "opening" is meant any means provided in the vibratory tray for disposing solid material into the barrel. The opening provides an optimal spread of fed material in the barrel.

Material is fed onto the vibratory tray (3) from a feeding end to a discharging end. The section (3a) of the vibratory tray between the feeding end and the opening is the feeding section. The section (3b) of the vibratory tray (3) between the opening and the discharging end provides for the export or discharge of the uplifted sunken material. The density separation device functions as a dynamic device whereby the liquid medium is continuously filled such that a drive volume is created and a constant overflow (8) is created. In this way, solid material particles that are lighter than the liquid separation medium float and are transported towards the other end (5) of the barrel. The floating fraction (9) may be collected in a container (13) or transfer chute. Material parts that are heavier than the liquid separation medium will sink between the blades (11 ) of the barrel, at which point the sunken material is uplifted onto the vibratory tray (3) and evacuated out of the barrel.

The discharge end of the barrel preferably has a conical region (5) for easier discharge.

Figure 3 illustrates the inside of the barrel. Sink fraction material is uplifted onto the discharge section (3b) of the vibratory tray (3) by blades (11 ) mounted on the inner surface of the barrel. Said heavier material will finally be transported on the vibratory tray out of the barrel onto a transportation band (12). A collector plate (16) aids the correct uplifting and sisposal of sunken material onto the discharging tray (3b).

Figure 5 illustrates a single-level vibratory tray (3) having a feeding section (3a) and a discharge section (3b) separated by the opening (6). The opening (6) may be provided with guiding means (6a) for guiding the material into the barrel. In this embodiment the opening is an inclined chute, inclined in the direction of the feeding.

The size of the opening (6) in the vibratory tray (3) may vary depending on the material size to be separated. The opening (6) may be provided near the upper end of the barrel, or near the middle or over at least part of the length of the barrel, as illustrated in Figure 6. In this embodiment the opening is a continuation of the feeding section having a triangular shape, whereby one side is parallel to the axis of the barrel. The continuation part running inside the barrel may have a different angle of inclination than that of the feeding section (3a). The opening plate (6) may be provided such that the shape of the opening and its length inside the barrel is adjustable depending on the fed material. Figures 6 and 7 illustrate a multilevel vibratory tray (3). In the barrel, the feeding section (3a) runs under the discharging section (3b), whereby material is fed into the barrel via a triangular shaped opening running along almost ¾ part of the inner barrel. The discharge section (3b) runs in a second level above this opening, from the upper end of the barrel up to the other end of the barrel. An optimal discharge path is hereby provided.

To prevent floating material from also being uplifted by the blades, the barrel is provided with axial plates or curtains (14) (Figure 3). A dewatering screen provided in the vibratory tray (discharge section 3b) may further drain the uplifted material.

The liquid medium is chosen such that its specific gravity is between the specific gravity of the particles of the float fraction and the specific gravity of the particles of the sink fraction.

The drained wash water or liquid medium is recuperated and recirculated into the barrel. The rotatable barrel is preferably made of sheet metal. The barrel is preferably positioned horizontally and turns around its longitudinal axis on drive wheels (15) that are running along the outer surface of the barrels.

Particle sizes that can be separated preferably vary between 0.25 and 150 mm.

In another embodiment the density separation device comprises one or more rotatable barrel constructions whereby sunken material is uplifted onto a vibratory tray of the invention. Industrial Applicability

Advantages of the separation device of the invention are the following:

- Minimal clogging during feeding and especially during discharging

- High throughput of material

- Compact installation

Simple construction

Uniform feeding into the barrel by means of specially shaped opening Optimal use of length of barrel via vibratory tray (discharging section) running through the barrel

The separation device of the present invention can be used for separating materials of different densities, e.g. vegetables, plastics, minerals, solid waste and ASR.

Claims

C L A I M S

1. Density separation device (1 ) for separating solid material particles in a float and a sink fraction by means of a liquid medium, the specific gravity of said liquid medium being between the specific gravity of the particles of the float fraction and that of the particles of the sink fraction, the device comprising

e. a rotatable barrel (2) having two open ends (4,5), said barrel comprising means (11 ) mounted on the inner surface of the barrel (2) for uplifting material,

f. feeding means (3a) at one open end (4) for feeding the solid material into the barrel (2),

g. discharging means (3b) at the other open end (5) for discharging sunken material, and

h. an overflow zone (8) for evacuating the float fraction and the medium, characterised in that said feeding means (3a) and said discharging means (3b) are comprised in a vibratory tray (3) running through the barrel (2) from one open end (4) to the other open end (5), whereby said feeding means (3a) is provided with at least one opening (6) through which the solid material can be introduced into the barrel (2), and said discharging means evacuates uplifted sunken material out of the barrel.

Device according to claim 1 , characterised in that said vibratory tray (3) is a single-level tray comprising a feeding section (3a) provided from one end (4) of the barrel up to an opening (6) for disposing solid material into the barrel, and a discharging section (3b) provided from said opening (6) to the other end (5) of the barrel.

Device according to claim 1 , characterised in that said vibratory tray (3) is a multi-level tray comprising a feeding section (3a) at a lower level provided from one end (4) of the barrel up to an opening (6) for disposing solid material into the barrel, and a discharging section (3b) at an upper level provided anywhere from the upper end (4) of the barrel to the other end (5) of the barrel.

Device according to any of the previous claims, characterised in that said opening (6) has a rectangular, trapezal or triangular shape, or any shape running along at least part of the length of the barrel.

Device according to any of the previous claims, characterised in that said opening (6) stretches anywhere between the upper end (4) of the barrel to the other end (5) of the barrel, preferably in the first half of the barrel.

Device according to any of the previous claims, characterised in that said vibratory tray (3) is positioned under an angle.

Device according to any of the previous claims, characterised in that said one open end (5) for providing an overflow of floats and medium is conical.

Device according to any of the previous claims, characterised in that said means (11 ) mounted on the inner surface of the barrel (2) for discharging sunken material is one or more blades or a helical scroll.

9. Device according to any of the previous claims, characterised in that said barrel (2) is further provided with axial plates or curtains (14) for preventing float material from being uplifted onto the discharging means (3b).

10. Device according to any of the previous claims, characterised in that said rotatable barrel (2) is positioned either horizontally along its longitudinal axis or inclined under an angle. 11. Device according to any of the previous claims, characterised in that a monodirectional flow of medium is provided, whereby said overflow zone (8) for floats and medium and said discharging open end (5) for sinks are on the same ends (5) of the barrel. Device according to any of the previous claims, characterised in that a bidirectional flow of medium is provided, whereby said overflow zone (8) for floats and medium and said discharging open end (5) for sinks are on opposite ends (4,5).

Method for the selective separation of solid material with a device of any of claims 1 to 12, characterised in that the method comprises the steps of

applying a constant flow (8) of liquid medium for evacuating the float fraction at one end (4,5) of the barrel (2),

uplifting the sunken material onto the vibratory tray (3) by the means (11 ) mounted in the inner surface of the barrel (2) and the rotation of the barrel (2), and

Method according to claim 13, whereby a flow of liquid medium is provided so that the overflow of float material (9) and medium is at the same end (5) of the barrel as the discharge end of sunken material (10).

15. Method according to claim 13, whereby a flow of liquid medium is provided so that the overflow of float material (9) and medium is at the opposite end (4) of the barrel as the discharge end (5) of sunken material (10).

16. Use of a device (1 ) according to any of claims 1 to 12 for separating materials of different densities, e.g. vegetables, plastics, minerals, solid waste and ASR.