Apparatus and method for the dry separation of particles

Patent metadata

Field	Value
Publication number	US-11148171-B2
Application number	US-201716321498-A
Country	US
Kind code	B2
Filing date	Aug 1, 2017
Priority date	Aug 1, 2016
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

An apparatus and method for the dry separation of bulk particulate material, especially coarse particles, is provided. The apparatus comprises a chamber, a screen adjacent the chamber and a fluidising device fluidly connected to the chamber. The screen has a screen surface, a plurality of apertures and an opening larger in size than the aperture. A mixture of the coarse particles and a fine particulate medium is fed into the chamber. The fluidising device directs a fluidising fluid to fluidise a fine particulate medium and create a fluidised bed directed towards the screen. The fine particulate medium and the coarse particles pass from the chamber through the openings. The fine particulate medium passes back through the apertures to the chamber. Relatively high density coarse particles also pass back through the openings to the chamber. Relatively low density coarse particles are retained on the screen surface. Vibrations may also be used.

First claim

The invention claimed is:

1. An apparatus for the dry separation of a mixture of coarse particles having low density coarse particles and high density coarse particles, comprising:
a chamber for receiving a fine particulate medium;
a screen adjacent said chamber for separating said mixture of coarse particles, said screen comprising a screen surface for receiving said mixture of coarse particles thereon, a plurality of apertures and one or more openings larger in size than said apertures; and
a fluidising device fluidly connected to said chamber for directing a fluidising fluid into said chamber to fluidise said fine particulate medium, thereby creating a fluidised bed directed towards said screen to carry said mixture of coarse particles towards said screen;
wherein said one or more openings are configured to permit said fine particulate medium and said mixture of coarse particles, carried by the fluidised bed to pass through said screen from said chamber;
said apertures are configured to permit said fine particulate medium to pass back through said screen to said chamber and to prevent said mixture of coarse particles, from passing back through said screen;
said one or more openings also being configured to permit the high density coarse particles to pass back through said screen to said chamber; and
said screen retains the low density coarse particles on said screen surface.

2. The apparatus of claim 1 , wherein said screen comprises a mesh and there is a plurality of said openings spaced apart at regular intervals in said mesh and between said apertures.

3. The apparatus of claim 1 , wherein said screen comprises a plate and there is a plurality of said openings spaced apart at regular intervals in said plate and between said apertures.

4. The apparatus of claim 1 , wherein there is a plurality of said openings, said openings being substantially the same size and having a diameter at least twice the maximum diameter of the high density coarse particles.

5. The apparatus of claim 1 , wherein the screen and the fluidising device are located at opposite sides of said chamber.

6. The apparatus of claim 1 , wherein said screen is located above said chamber and said fluidising device is located below said chamber.

7. The apparatus of claim 1 , further comprising a cover for preventing escape of said fine particulate medium, said cover having an exhaust for controllably removing said fine particulate medium, wherein said exhaust is fluidly connected to a recycling conduit for returning said fine particulate medium to said chamber.

8. The apparatus of claim 1 , wherein said chamber comprises a first vibration mechanism for facilitating movement of said mixture of coarse particles, across said screen, said first vibration mechanism being connected to the chamber and/or the screen.

9. The apparatus of claim 8 , wherein said chamber comprises a second vibration mechanism for influencing the fluidisation of the fine particulate medium and/or facilitating formation of a homogeneous fluidised bed, said second vibration mechanism being connected to the chamber and/or the screen.

10. The apparatus of claim 1 , wherein said screen comprises two or more openings that are different in size to permit the high density coarse particles of different sizes to pass back through said screen to the chamber.

11. The apparatus of claim 10 , wherein there are a greater number of openings that are smaller in size than the number of openings that are larger in size.

12. The apparatus of claim 10 , wherein a first group of openings has a diameter of 6 mm, a second group of openings has a diameter of 12 mm and a third group of openings has a diameter of between 15 and 20 mm.

13. The apparatus of claim 12 , wherein said screen comprises a fourth group of openings located near an outlet, said fourth group of openings being configured to remove said low density coarse particles from said screen.

14. A method for the dry separation of a mixture of coarse particles having low density coarse particles and high density coarse particles, comprising:
feeding a fine particulate medium into a chamber;
providing a screen with a screen surface for receiving said mixture of coarse particles thereon, a plurality of apertures and one or more openings larger in size than said apertures;
directing a fluidising fluid through said chamber to fluidise said fine particulate medium, thereby creating a fluidised bed directed towards said screen;
carrying said mixture of coarse particles towards said screen by way of said fluidised bed;
configuring said one or more openings so that:
said fine particulate medium and said mixture of coarse particles, carried by said fluidised bed pass through said one or more openings from said chamber; and
the high density coarse particles pass back into said chamber through said one or more openings;

configuring the apertures so that:
said fine particulate medium passes through said apertures back into said chamber; and
said mixture of coarse particles, are prevented from passing back through said apertures; and

retaining the low density coarse particles on said screen surface.

15. The method of claim 14 , wherein there is a plurality of said openings, the method further comprising spacing apart said openings at regular intervals in the screen and between the apertures.

16. The method of claim 14 , comprising varying a flow rate of the fluidising flow across the screen.

17. The method of claim 14 , comprising removing said fine particulate medium displaced from said screen and recycling said fine particulate medium to said chamber.

18. The method of claim 14 , comprising vibrating said chamber and/or screen to facilitate movement of said mixture of coarse particles, across said screen, influence the fluidisation of the fine particulate medium, facilitate formation of a homogeneous fluidised bed or any combination thereof.

19. The method of claim 14 , comprising providing two or more openings that are different in size to permit the high density coarse particles of different sizes to pass back through said screen to the chamber.

20. The method of claim 19 , comprising providing a greater number of openings that are smaller in size than the number of openings that are larger in size.

Assignees

• Univ Newcastle

Inventors

• Galvin Kevin Patrick

Classifications

• B01J8/32

  with introduction into the fluidised bed of more than one kind of moving particles · CPC title

• B01J8/0065

  by impingement against stationary members · CPC title

• B01J2208/00672

  Particle size selection · CPC title

• B01J8/1854

  followed by a downward movement inside the reactor to form a loop · CPC title

• B01J8/18

  with fluidised particles {(combustion apparatus with fluidised bed in general F23C10/00; furnaces with fluidised bed F27B15/00)} · CPC title