WO2004041436A2

WO2004041436A2 - A rotary scrubber

Info

Publication number: WO2004041436A2
Application number: PCT/ZA2003/000162
Authority: WO
Inventors: Gerald Anthoney De Jongh
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-11-04
Filing date: 2003-11-03
Publication date: 2004-05-21
Anticipated expiration: 2005-05-04
Also published as: AU2003291209A8; AU2003291209A1; WO2004041436A3

Abstract

The invention relates to a rotary scrubber for particulate materials which has a support frame with which a cylindrical body is rotatably engaged. The body has an inlet at a first end thereof, an outlet at a second end thereof, an inner side wall, an outer side wall and an elongate, tubular screen member which is attached to and spaced from the inner side wall and which extends inside the body from the inlet to the outlet. The invention also provides a method of processing a particulate material using the rotary scrubber.

Description

A ROTARY SCRUBBER

BACKGROUND OF THE INVENTION

[0001] This invention relates to a rotary scrubber used for the scrubbing of particulate materials such as ore, stone, gravel, sandstone etc. SUMMARY OF THE INVENTION

[0002] The invention provides a rotary scrubber for particulate materials which includes a rotatable, cylindrical body with an inlet at a first end thereof, an outlet at a second end thereof, an inner side wall and an outer side wall, and an elongate, tubular first screen member which extends at least partially from the inlet into the body. [0003] The body may include a lining formation in the form of a rubber lining on the inner side wall to provide at least limited protection to the body from the particulate materials scrubbed inside the body.

[0004] The body may include a plurality of elevation formations attached to the inner side wall. Each elevation formation may be in the form of an upstanding rib. [0005] Preferably the first screen member extends from the inlet to the outlet and is spaced from the inner side wall. The first screen member may move in unison with the body and may be fixed to the body. Alternatively the first screen member may be releasably attached to the body.

[0006] Preferably the first screen member includes a spiral formation extending along the length of the first screen member. The pitch of the spiral formation may be between 110 mm and 210 mm and preferably is between 155 mfri and 165 mm.

[0007] The scrubber may include a support formation whereon the body is rotatably received. The support formation may include a frame and a plurality of runners, each of which is rotatably attached to the frame and engaged with the outer side wall of the body.

[0008] The scrubber may include a drive mechanism in the form of an electromechanical mechanism or a hydraulic mechanism to rotate the body. Preferably the drive mechanism includes a drive wheel which is engaged with the body.

[0009] The scrubber may include a discharge formation attached to the outlet. The discharge formation may be cylindrically shaped and may include a second screen member. [0010] The second screen member may include a plurality of apertures, each of which may have a diameter of between 10 mm and 60 mm. Preferably each aperture has a diameter of between 25 mm and 35 mm.

[0011] The second screen member may be in the form of a trommel. [0012] A first discharge chute may be in communication with the second screen . member, a second discharge chute may be in communication with a space between the first and second screen members and a third discharge chute may be in communication with the first screen member in order to transport processed particulate materials away from the discharge formation and the body. [0013] A plurality of brackets may be located between the body and the first screen member.

[0014] The invention also extends to a rotary scrubber for particulate materials which includes a support frame, a cylindrical body with an inlet at a first end thereof, an outlet at a second end thereof, an inner side wall and an outer side wall, the body being rotatably engaged with the support frame, and an elongate, tubular first screen member which is attached to and spaced from the inner side wall and which extends inside the body from the inlet to the outlet.

[0015] A cylindrical discharge formation may be provided on the outlet, which discharge formation may have a second screen member. Preferably the first screen member extends into the discharge formation.

[0016] The invention also provides a method of processing a particulate material which includes the steps of: a) feeding the particulate material into an elongate, tubular first screen member located inside a cylindrical body of a rotary scrubber; and b) separating the particulate material into a first fraction of generally a first particle size located inside the first screening member and a second fraction of generally a second particle size located outside the first screening member and inside the body, and wherein the first particle size is larger than the second particle size. [0017] The method may include any one of or combination of the following steps: c) milling the first fraction within the first screening element; d) milling the second fraction within the body; and e) scrubbing the first and the second fractions within the body.

[0018] Preferably the steps b, c, d and e take place simultaneously.

[0019] The method may include the step of separating the second fraction into a third fraction of generally a third particle size and a fourth fraction of generally a fourth particle size wherein the third particle size is larger than the fourth particle size. The third and the fourth fractions may each be separately subjected to further processing and preferably the fourth fraction is subjected to a liquid/solid separation step. [0020] The first fraction may be subjected to further processing separately from the second fraction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention is further described by way of example with reference to the accompanying drawings in which: Figure 1 is a side view of a rotary scrubber according to the invention;

Figure 2 is a sectioned side view on the line 2-2 in Figure 1 of the scrubber of Figure 1 ;

Figure 3 is a sectioned side view on the line 3-3 in Figure 2 of the scrubber of Figure 1; and

Figure 4 is a schematic representation of a method of processing particulate materials according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENT

[0022] Figures 1, 2 and 3 of the accompanying drawings illustrate a rotary scrubber 10 which has a support 12 with which a drum 14 is rotatably engaged.

[0023] The support 12 has a frame 16 to which a plurality of runners 18 are attached by means of shafts 20. A drive mechanism 22 in the form of an electromechanical drive of known construction is connected to a drive wheel 24. The drive wheel 24 is also attached to the frame 16 by means of a shaft 20 and is engaged with the drum 14.

[0024] The frame 16 is made from an appropriate metal material and the runners 18 and drive wheel 24 are in the form of pneumatic tyres. The electro- mechanical drive can be replaced with a hydraulic drive or any other appropriate mechanism to impart movement to the drive wheel 24.

[0025] The drum 14 has an elongate cylindrical shaped body 25 formed from metal sheet material with an inlet 26 at a first end 28 thereof, an outlet 30 at a second end 32 thereof and an inner side wall 34 and an outer side wall 36 on opposite sides of the sheet material. The drum 14 can be of any appropriate dimensions and in this example is 5 meters in long and has a diameter of 3 meters. End flanges 38A, B are respectively situated at the inlet 26 and outlet 30. Stiffening rings 40A, B, which extend around the outer side wall 36, reinforce the drum 14. The drum 14 is cradled on the runners 18 and drive wheel 24 so that the runners 18 and the drive wheel 24 engage with the outer side wall 36.

[0026] The drum 14 is made in a known manner from any appropriate metal material.

[0027] A rubber lining 42 is attached to the inner side wall 34 in order to protect the drum 14 from particulate materials (not shown) fed into the drum 14 and agitated inside the drum 14.

[0028] A plurality of elevation formations or lifter bars 44 are also attached to the inner side wall 34. Each of the lifter bars 44 is in the form of an upstanding rib and is reinforced by a plurality of gussets 46 [0029] A tubular, elongate screen member 48 extends inside the drum 14 from the inlet 26 to the outlet 30. The screen member 48 is spaced from the inner side wall 34 by way of a plurality of brackets 50. Each bracket 50 extends radially from the screen member 48 to the inner side wall 34. The screen member 48 is permanently fixed to the drum 14 by way of the brackets 50. Alternatively the screen member 48 is releasably attached to the drum 14 by way of the brackets 50 to allow replacement of the screen member 48 if required.

[0030] The screen member 48 is in the form of a continuous spiral which has a diameter of approximately 1 500 mm. The pitch of the spiral 48 can vary according to requirements and can be between 110 mm and 210 mm. Through experimentation the applicant has found that a pitch of between 155 and 165 mm is preferable for most types of ore, stone or gravel processed in diamond recovery processes. In this example the pitch is 160 mm. [0031] A feeding chute 52 extends at least partially into the screen member 48 at the inlet 46 to deliver the particulate material into the screen member 48.

[0032] At the outlet 30 a discharge formation or trommel 54 is attached to the drum 14. The trommel 54 is cylindrically shaped and has a screen 56. The screen 56 has a plurality of aperture or holes 58. Again depending on requirements the size and shape of the apertures 58 can vary and the diameter of the apertures 58 can vary between 10 mm and 60 mm. Through experimentation the applicant has found that a diameter of between 25 mm and 35 mm is preferable for ore, stone or gravel processed in diamond recovery processes. In this example the diameter is 30 mm. [0033] The screen member 48 extends into the trommel 54 and a space 60 is defined between the screen 56 and the screen member 48.

[0034] The screen member 48 and the trommel 54 are made from appropriate metal materials.

[0035] A first discharge chute 62 is in communication with the apertures 58 in the screen 56. A second discharge chute 64 is in communication with the space 60 and a third discharge chute 66 is in communication with the inside of the screen member 48. These chutes 62, 64 and 66 are of known construction.

[0036] In use, and as schematically shown in Figure 4, a particulate material 68 is fed into the screen member 48 by way of the feeding chute 52 while the drum 14 is rotated by the drive wheel 24. The drum 14 runs on the runners 18 in a known manner which results in the continuous, displacement and agitation of the particulate material 68 inside the screen member 48. As the particulate material 68 is agitated inside the screen member 48 particles of a size less than the pitch of the spiral (in this case 160 mm) move out of the screen member 48 towards the inner side wall 34. In this manner the particulate material 68 is separated into a first fraction 69 of generally a first particle size and a second fraction 70 of generally a second particle size. It is to be understood that the first particle size is larger than the second particle size.

[0037] As the drum 14 is rotated in the direction 72 the second fraction 70 remains inside the drum 14 and is agitated in a known manner. The lifter bars 44 assist in this agitation as portions of the second fraction 70 are lifted away from a lower end of the drum 14 and thrown away from the inner side wall 34. In this way the cascading action of the second fraction 70 within the drum 14 is enhanced which assists in the milling of the second fraction 70 inside the drum 14. [0038] The screen member 48 moves in unison with the drum 14 and the first fraction 69 inside the screen member 48 is also agitated and milled in a known manner. The spiralling structure of the screen member 48 results in the first fraction 69 being moved along the length of the screen member 48 toward the outlet 30 while the milling action of the first fraction 69 continues.

[0039] The screen member 48 acts as an auger on the second fraction 70 and the second fraction 70 is also displaced towards the outlet 30.

[0040] Simultaneously with the separation action of the particulate material 68 into the first and second fractions 69 and 70 and the milling action of the first and second fractions 69 and 70, liquid 74 is fed into the drum 14 through the inlet 26. The liquid 74 can be water or any other chemical used during the processing of the particulate material 68 which causes scrubbing of both the first and second fractions 69 and 70 inside the drum 14 while the separation and milling actions continue.

[0041] As the remainder of the particulate material 68 forming part of the first fraction 69 reaches the trommel 54 the first fraction 69 is discharged from the screen member 48 into the third discharge chute 66 through which the first fraction 69 is carried away to further processing 75A.

[0042] As the second fraction 70 reaches the trommel 54 a second separation takes place and the second fraction 70 is separated into a third fraction 76 of generally ^• a third particle size and a fourth fraction 78 of generally a fourth particle size. This occurs as a result of a screening action which takes place on the screen 56 and as particles of the fourth particle size (less than 30 mm) move together with the liquid 74 through the apertures 58 into the first discharge chute 62. The third particle size is therefore larger than the fourth particle size 78. The third fraction 76 remains in the space 60 between the screening member 48 and the screen 56, is expelled from the space 60 into the second discharge chute 64 and is carried to further processing 75B.

[0043] The liquid 74 and fourth fraction 78 move along the first discharge chute 62 to further processing 75C. The liquid 74 and fourth fraction 78 are separated in a liquid/solid separation step 80. The liquid 74 is further processed as required or recycled. The fourth fraction 78 is further processed separately from the liquid 74.

[0044] In this manner the particulate material 68 is simultaneously milled, scrubbed and screened into three fractions. The first fraction 69 is processed separately from the second, third and fourth fractions 70, 76 and 78. The third and fourth fraction 76 and 78 are also processed separately from one another. [0045] Depending on the requirements the support 12 may be inclined to provide gravitational flow of the particulate material 68 inside the drum 14 in order to assist in the displacement of the particulate material 68 along the length of the drum 14 from the inlet 26 towards the outlet 30. [0046] As the weight of the particulate material 68 in the screen member 48 at the inlet 26 is generally higher than the weight of the first fraction 69 in the screen member 48 at the outlet 30, more brackets 50 are used to attach the screen member 48 to the drum 14 at the inlet 26 than at the outlet 30.

[0047] As larger particles in the first fraction 69 are confined to the screen member 48 damage to the lining 42 and inner side wall 34 is reduced. The milling action between the larger particles is also enhanced and the balance of the rotating drum 14 is improved. Additionally the crushing effect of the larger particles in the first fraction 69 on the smaller particles in the second fraction 70 is reduced which is of particular importance in the diamond mining industry where unnecessary damage to precious stones should be limited.

[0048] Although the screen member 48 in this example extends the entire length of the drum 14 it is envisaged that the screen member 48 may extend only a limited length from the inlet 26 into the drum 14. In this case the screen member 48 is used initially to separate the first and second fractions 69 and 70 so that the milling of the first fraction 69 inside the screen member 48 is initially separated from that of the second fraction 70. The second fraction 70, the lining 42 and the inner side wall 34 at the inlet 26 are in this manner also protected from immediate exposure to large and heavy particles.

Claims

1. A rotary scrubber for particulate materials (68) which includes a rotatable, cylindrical body (14, 25) with an inlet (26) at a first end (28) thereof, an outlet (30) at a second end (32) thereof, an inner side wall (34) and an outer side wall (36) and characterised in an elongate, tubular first screen member (48) which extends at least partially from the inlet into the body.

2. A scrubber according to claim 1 characterised therein that the first screen member extends from the inlet to the outlet.

3. A scrubber according to claim 1 or 2 characterised therein that wherein the first screen member is spaced from the inner side wall.

4. A scrubber according to claim 1 , 2 or 3 characterised therein that the first screen member is fixed to the body and moves in unison with the body.

5. A scrubber according to any one of claims 1 to 4 characterised therein that the first screen member includes a spiral formation.

6. A scrubber according to claim 5 characterised therein that the pitch of the spiral formation is between 110 mm and 210 mm.

7. A scrubber according to claim 6 characterised therein that the pitch is between 155 mm and 165 mm.

8. A scrubber according to any one of claims 1 to 7 characterised therein that it includes a discharge formation (54) attached to the outlet.

9. A scrubber according to claim 8 characterised therein that the discharge formation is cylindrically shaped and includes a second screen member (56).

10. A scrubber according to claim 9 characterised therein that the second screen member includes a plurality of apertures (58), each of which has a diameter of between 10 mm and 60 mm.

11. A scrubber according to claim 10 characterised therein that each aperture has a diameter of between 25 mm and 35 mm.

12. A scrubber according to claim 9, 10 or 11 characterised therein that the second screen member is in the form of a trommel.

13. A scrubber according to any one of claims 9 to 12 characterised therein that it includes a first discharge chute (62) in communication with the second screen member.

14. A scrubber according to any one of claims 9 to 13 characterised therein that it includes a second discharge chute (64) in communication with a space (60) between the first and second screen members.

15. A scrubber according to any one of claims 1 to 14 characterised therein that it includes a third discharge chute (66) in communication with the first screen member.

16. A scrubber according to any one of claims 1 to 15 characterised therein that it includes a plurality of brackets (50) between the body and the first screen member.

17. A scrubber according to any one of claims 1 to 16 characterised therein that the body includes a lining formation (42) on the inner side wall.

18. A scrubber according to claim 17 characterised therein that the lining formation is in the form of a rubber lining.

19. A scrubber according to any one of the claims 1 to 18 characterised therein that the body includes a plurality of elevation formations (44) attached to the inner side wall.

20. A scrubber according to claim 19 characterised therein that each of the elevation formations is in the form of an upstanding rib.

21. A scrubber according to any one of claims 1 to 20 characterised therein that it includes a support formation (12, 16) whereon the body is rotatably received

22. A scrubber according to claim 21 characterised therein that the support formation includes a frame (12) and a plurality of runners (18), each of which is rotatably attached to the frame and engaged with the outer side wall.

23. A scrubber according to any one of claims 1 to 22 characterised therein that it includes a drive mechanism (22) to rotate the body.

24. A scrubber according to claim 23 characterised therein that the drive mechanism is in the form of an electro-mechanical mechanism or a hydraulic mechanism.

25. A scrubber according to claim 23 or 24 characterised therein that the drive mechanism includes a drive wheel (24) which is engaged with the body.

26. A method of processing a particulate material (68) in a rotary scrubber (10) according to any one of claims 1 to 25 characterised therein that it includes the steps of:

a) feeding the particulate material into the first screen member; and

b) separating the particulate material into a first fraction (69) of generally a first particle size located inside the first screening member and a second fraction (70) of generally a second particle size located outside the first screening member and inside the body, and wherein the first particle size is larger than the second particle size.

27. A method according the claim 26 characterised therein that it includes the step of:

c) milling the first fraction within the first screening element.

28. A method according to claim 26 or 27 characterised therein that it includes the step of:

d) milling the second fraction within the body.

29. A method according to claim 26, 27 or 28 characterised therein that it includes the step of:

e) scrubbing the first and the second fractions within the body.

30. A method according to claims 26 to 29 characterised therein that steps b, c, d and e take place simultaneously.

31. A method according to any one of claims 26 to 30 characterised therein that it includes the step of separating the second fraction into a third fraction (76) of generally a third particle size and a fourth fraction (78) of generally a fourth particle size wherein the third particle size is larger than the fourth particle size.

32. A method according to claim 31 characterised therein that the third and the fourth fractions are each separately subjected to further processing (75B, 75C).

33. A method according to claim 31 or 32 characterised therein that it includes the step of subjecting the fourth fraction to a liquid/solid separation step (80).

34. A method according to any one of claims 26 to 33 characterised therein that the first fraction is subjected to further processing (75A) separately from the second fraction.

35. A rotary scrubber for particulate materials (68) which includes a rotatable, cylindrical body (14, 25) with an inlet (26) at a first end (28) thereof, an outlet (30) at a second end (32) thereof, an inner side wall (34) and an outer side wall (36) and characterised in an elongate, tubular first screen member (48) which extends from the inlet to the outlet and has a spiral formation, a discharge formation (54) attached to the outlet which has a second screen member (56), a first discharge chute (62) in communication with the second screen member, a second discharged chute (64) in communication with a space (60) between the first and second screen members, and a third discharge chute (66) in communication with the first screen member.