Apparatus for separating particles of different sizes by means of cyclonic separation

1. An apparatus ( 1 ) for separating smaller particles from larger particles by cyclonic separation, comprising:

a feeding pipe ( 2 ) having an upper end ( 2 a ) for receiving material to be separated and defining a first channel ( 3 ) for transporting the material to a lower end ( 2 b ) of the feeding pipe,

a separation chamber ( 5 ) having an outer curved wall ( 7 ), a first opening ( 6 a ) arranged at an upper end ( 5 a ) of the separation chamber ( 5 ), a second opening ( 6 b ) arranged at a lower end ( 5 b ) of the separation chamber ( 5 ), and surrounding the feeding pipe ( 2 ),

a second channel ( 8 ) formed between the feeding pipe ( 2 ) and the outer curved wall ( 7 ),

an air inlet unit ( 12 ) arranged for supplying air to the second opening ( 6 b ) of the separation chamber ( 5 ), and

an outlet unit ( 15 ) arranged for receiving air and separated material from the first opening ( 6 a ) of the separation chamber ( 5 ) and discharging the air and separated material, wherein

the feeding pipe ( 2 ) and the separation chamber ( 5 ) are concentrically arranged, and

the second channel ( 8 ) is conically-shaped and continuously decreases toward the upper end ( 5 a ) of the separation chamber ( 5 ).

2. The apparatus according to claim 1 , wherein said air inlet unit ( 12 ) comprises a housing ( 13 ) defining a curved third channel ( 46 ) for the air flow having an inlet opening ( 14 ) for receiving the air and the third channel is arranged in communication with a lower end ( 8 b ) of the second channel to allow the air flow in the curved third channel ( 46 ) to enter the lower end of the second channel ( 8 ),

said outlet unit ( 15 ) comprises a housing ( 16 ) defining a curved fourth channel ( 48 ) for the air flow having an outlet opening ( 17 ) for discharging the air and separated material,

the fourth channel is arranged in communication with an upper end ( 8 a ) of the second channel to allow the air flow in the second channel ( 8 ) to enter the fourth channel ( 48 ), and

the apparatus comprises a suction unit ( 18 ) operatively connected to the outlet opening ( 17 ) of the outlet unit ( 15 ) and arranged for sucking air from said inlet opening ( 14 ) to said outlet opening ( 17 ) via said third, second and fourth channels so that a rotating air flow ( 22 ) is formed in said second channel ( 8 ) and smaller particles are transported upwards to the outlet unit ( 15 ) by the rotating air flow while larger particles are moved downwards due to gravity.

3. The apparatus according to claim 2 , wherein said curved third channel ( 46 ) surrounds the separation chamber ( 5 ) and said curved fourth channel ( 48 ) surrounds the feeding pipe.

4. The apparatus according to claim 2 , wherein said first opening ( 6 a ) is annular and surrounds the feeding pipe ( 2 ), and the fourth channel ( 48 ) is arranged in communication with the second channel ( 8 ) via said first opening ( 6 a ) of the separation chamber ( 5 ).

5. The apparatus according to claim 4 , wherein the housing ( 16 ) of the outlet unit ( 15 ) is attached to the upper end ( 5 a ) of the separation chamber ( 5 ), and the housing ( 16 ) of outlet unit surrounds said first opening ( 6 a ) of the separation chamber.

6. The apparatus according to claim 2 , wherein the air inlet unit ( 12 ) comprises a third opening ( 35 ) arranged in communication with the second opening ( 6 b ) of the separation chamber to allow the rotating air flow ( 22 ) in the curved third channel ( 46 ) to enter the second channel ( 8 ), and said third opening ( 35 ) is annular.

7. The apparatus according to claim 6 , wherein the third opening ( 35 ) is formed between the separation chamber ( 5 ) and the housing ( 13 ) of the air inlet unit ( 12 ) and said third opening ( 35 ) surrounds the separation chamber ( 5 ).

8. The apparatus according to claim 2 , wherein the suction unit ( 18 ) comprises a fan ( 19 ) with a variable speed.

9. The apparatus according to claim 1 , wherein the apparatus comprises an impeller ( 25 ) rotatably arranged below the feeding pipe ( 2 ) and at a distance from the lower end ( 2 b ) of the feeding pipe, and the curved wall ( 7 ) of the separation chamber surrounds the impeller ( 25 ) such that a gap ( 27 ) is formed between the curved wall ( 7 ) and the outer periphery ( 26 ) of the impeller.

10. The apparatus according to claim 9 , wherein said impeller ( 25 ) is arranged rotatable about an axis of symmetry ( 30 ) of the separation chamber ( 5 ), and the rotation of the impeller ( 25 ) is driven by said rotating air flow ( 22 ) caused by the suction unit.

11. The apparatus according to claim 10 , wherein said second opening ( 6 b ) of the separation chamber is arranged below the impeller ( 25 ) for receiving air from the air inlet unit ( 12 ), and the air inlet unit ( 12 ) is arranged for supplying air to the second opening ( 6 b ) of the separation chamber.

12. The apparatus according to claim 9 , wherein said second opening ( 6 b ) of the separation chamber is arranged below the impeller ( 25 ) for receiving air from the air inlet unit ( 12 ), and the air inlet unit ( 12 ) is arranged for supplying air to the second opening ( 6 b ) of the separation chamber.

13. The apparatus according to claim 9 , wherein the apparatus comprises a collector unit ( 38 ) disposed below said gap ( 27 ) for collecting separated larger particles.

14. The apparatus according to claim 1 , wherein the apparatus comprises an air lock ( 44 ) arranged to prevent air from entering the first channel together with the unseparated material.

15. The apparatus according to claim 1 , wherein the apparatus comprises a filter unit ( 40 ) arranged between the outlet unit ( 15 ) and the suction unit ( 18 ).

16. The apparatus according to claim 1 , wherein the second channel ( 8 ) is shaped such that radial width thereof (d 1 -d 2 ) decreases toward the upper end ( 5 a ) of the separation chamber ( 5 ).