Screening Apparatus

Abstract

The present invention relates to a screening apparatus (100) comprising a frame (10); a feed conveyor (20) mounted at one end of the frame and a screen (30) for accepting waste material from the feed conveyor, the waste material comprising fines and oversize material. The screen (30) is mounted on the frame (10) about a pivot axis and comprises a trough (32) with a top opening; and a plurality of driven elongate rotating members (40) disposed in an arc along one side of the trough and along at least a portion of the base of the trough (32) for causing circular or helical flow of the waste material within the trough. The trough (32) further comprises a base opening for discharging the fines material and an oversize material outlet for discharging the oversize material; and wherein the screen is mounted on the frame such that the elongate rotating members (40) are each independently perpendicular to the pivot axis.

Claims

1. A screening apparatus for screen waste material, wherein the waste material contains fine material and oversize material, said screening apparatus comprising: a frame; a feed conveyor mounted at one end of the frame; and a screen for accepting the waste material from the feed conveyor, wherein the screen is mounted on the frame about a pivot axis and comprises: a trough with a first side, a second side, a base and a top opening; and a plurality of driven elongate rotating members disposed in an arc along one side of the trough and along at least a portion of the base of the trough for causing circular or helical flow of the waste material within the trough, wherein each of said plurality of driven elongate rotating members has a shaft and a plurality of mutually parallel blades, wherein the trough further comprises a base opening for discharging the fine material and an oversize material outlet for discharging the oversize material; and wherein the screen is mounted on the frame such that the elongate rotating members are each independently perpendicular to the pivot axis.

2. The screening apparatus of claim 1, wherein the screen comprises a first plurality of driven elongate rotating members disposed in a first arc along the first side and along at least a portion of the base of the trough and a second plurality of driven elongate rotating members disposed in a second arc along the second side of the trough and along at least a portion of the base of the trough.

3. The screening apparatus of claim 2, wherein the first plurality of driven elongate rotating members is driven to run in the opposite direction to that of the second plurality of driven elongate rotating members.

4. The screening apparatus of claim 2, wherein there are at least five driven elongate rotating members disposed in the first arc.

5. (canceled)

6. The screening apparatus of claim 1, wherein each of the blades independently has a plurality of curved radial extensions which act on the waste material during the rotation thereof.

7. The screening apparatus of claim 1, wherein the screen further comprises a feed inlet for accepting the waste material from the feed conveyor such that the feed inlet is beneath the feed conveyor.

8. The screening apparatus of claim 1, further including at least one secondary screen.

9. The screening apparatus of claim 1, wherein the screening apparatus further comprises at least one conveyor to collect and stockpile the waste material that passes through the screen.

10. The screening apparatus of claim 1, wherein the oversize material outlet is disposed at an end of the trough opposite the feed conveyor.

11. The screening apparatus of claim 1, wherein the screening apparatus further comprises a ram assembly to alter the screen with respect to the frame about the pivot axis.

12. The screening apparatus of claim 1, wherein the screen is removably mounted to the screening apparatus.

13. The screening apparatus of claim 1, wherein the screen is pivotally mounted on the frame such that at least a portion of the top opening of the trough is located beneath the feed conveyor.

14. The screening apparatus of claim 1, wherein the screening apparatus further comprises a static feed plate between the feed conveyor and the screen.

15. The screening apparatus as claimed in claim 6 wherein each of the blades is manufactured from toughened steel, mild steel or hard wearing plastics such as polyurethane.

16. The screening apparatus according to claim 7, wherein the feed inlet is in the form of a chute.

17. The screening apparatus of claim 12, wherein the screen is slidably mounted to the frame to facilitate removal of the screen.

18. The screening apparatus of claim 1, wherein the feed conveyor is slidably mounted to the frame and can be selectively moved to facilitate removal of the screen.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Certain preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0039] FIG. 1 shows a perspective view of a preferred embodiment of the screening apparatus according to the invention;

[0040] FIG. 2a shows a perspective view of the screen of the screening apparatus of FIG. 1;

[0041] FIG. 2b shows a plan view of the screen of FIG. 2a;

[0042] FIG. 2c shows an end view of the screen of FIG. 2a;

[0043] FIG. 3 shows a preferred elongate rotating member of the screen of the screening apparatus of FIG. 1;

[0044] FIG. 4a shows a side view of two inline screens in series;

[0045] FIG. 4b shows a side view of two stepped screens in series;

[0046] FIG. 5a shows a side view of the screening apparatus of FIG. 1 with the screen at zero degrees;

[0047] FIG. 5b shows an enlarged view of the ram assembly used in FIG. 5a;

[0048] FIG. 6a shows a side view of the screening apparatus of FIG. 1 with the screen tilted;

[0049] FIG. 6b shows an enlarged view of the ram assembly used in FIG. 6a;

[0050] FIG. 7 shows a perspective view of an alternative preferred embodiment of the screening apparatus according to the invention;

[0051] FIG. 8 shows a plan view of the screening apparatus of FIG. 7;

[0052] FIG. 9 shows a perspective view of the screen of the screening apparatus of FIG. 7;

[0053] FIG. 10 shows another perspective view of the screening apparatus of FIG. 7;

[0054] FIG. 11 shows an end view of the screen of FIG. 7;

[0055] FIG. 12 shows an outlet end view of the screen of FIG. 7;

[0056] FIG. 13a shows a plan view of the screen of FIG. 7;

[0057] FIG. 13b shows a sectional view along line A-A in FIG. 13a;

[0058] FIG. 13c shows a sectional view along line B-B in FIG. 13a;

[0059] FIG. 14a shows a side view of the screen of FIG. 9 when mounted upwards 7 degrees;

[0060] FIG. 14b shows a perspective view of the screen of FIG. 14a;

[0061] FIG. 15a shows a side view of the screen of FIG. 9 when mounted upwards 3 degrees;

[0062] FIG. 15b shows a perspective view of the screen of FIG. 15a; and

[0063] FIG. 16 shows a perspective view of another alternative preferred embodiment of the screening apparatus according to the invention.

DETAILED DESCRIPTION

[0064] Various embodiments of the present invention will be described in detail with reference to the drawings, where like reference numeral represent like parts and assemblies throughout the several views.

[0065] Referring to the drawings, FIG. 1 shows a preferred screening apparatus according to the invention, generally referred to herein by reference numeral 100. As shown, screening apparatus 100 comprises frame 10, feed hopper 20 mounted at one end of frame 10 and screen 30 pivotally mounted on frame 10 about pivot axis P. In the preferred embodiment shown in FIG. 1, screening apparatus 100 is static and placed on containment bays C for collecting discharged fines and oversize material. However, the screening apparatus according to the invention may alternatively be provided with any one or more of wheels, tracks and hooklift.

[0066] As shown in FIGS. 2a to 2c, screen 30 comprises feed inlet 31 for accepting waste material from hopper 20, trough 32 and six interconnected driven elongate rotating members 40 disposed in an arc along one side and the base of trough 32. Arrows F in FIG. 2c show the direction of flow of the material within screen 30 during use when angled with respect to frame 10.

[0067] Screen 30 is mounted on frame 10 such that feed inlet 31 is located beneath the output end of feed hopper 20.

[0068] As shown in the preferred screen of FIGS. 2a to 2c, feed inlet 31 is in the form of a three-sided chute.

[0069] As well as being open at the top for accepting waste material from feed inlet 31 and open at the base to allow fine material to be discharged, trough 32 is provided with outlet 33 for discharging oversize material. Oversize outlet 33 is shown at the front of trough 32 in the Figures, i.e. at the opposite end of screen 30 to feed inlet 31. Alternatively, an oversize material outlet (not shown) may be at a side of trough 32, close to the front of the trough, or both, wherein each oversize material outlet independently may be plated off in order to change direction of outlet flow of oversize material.

[0070] Each of interconnected driven elongate rotating members 40 has a shaft 41 and a plurality of mutually parallel and overlapping star shaped agitations 42. An example of rotating member 40 is shown in FIG. 3. Each star shaped agitator 42 independently has a plurality of radial extensions 43 which act on the material during the rotation thereof. The star shaped agitator can be manufactured from any suitable material such as toughened steel, mild steel and hard wearing plastics material such as polyurethane.

[0071] As can be seen from FIG. 1, shafts 41 are each independently perpendicular to pivot axis P by which screen 30 is pivotally mounted on frame 10.

[0072] Rotating members 40 are actuated by a motor, for example variable speed electric motor 35. A first toothed pulley 36 is keyed onto the output shaft of motor 35 and a plurality of second toothed pulleys 37 are keyed onto respective ends of rotating members 40 outside of trough 32 and coupled to first toothed pulley 36 by means of chains 38.

[0073] As shown in FIGS. 4a and 4b, two screens 30 may be combined in series, either in line as in FIG. 4a or stepped with respect to each other as in FIG. 4b. In these embodiments only the first screen is provided with feed inlet 31. When placed in line, the oversize material outlet is at the side of the second trough.

[0074] Combining screens in series can be used to increase the screening length, or, if different speeds or blades are used to give more products of differing sizes, e.g. fines material with a diameter less than 10 mm, material with a diameter of from about 10 mm to about 25 mm and oversize material with a diameter of from 25 mm. However, these diameters are not to be considered limiting.

[0075] As shown in FIGS. 5a, 5b, 6a and 6b screening apparatus 100 further comprises ram assembly 50 to alter the pivot angle of screen 30 with respect to frame 10, i.e. along pivot axis P, to allow alteration of the retention time of the waste material within trough 32. For example, screen 30 may be mounted at 0 degrees as in FIG. 5a, angled such that the outlet 33 is raised to retain the material for longer (not shown) or angled downwards such that outlet 33 is lowered, e.g. by about 6 degrees as in FIG. 6a, such that the material remains on screen 30 for a shorter time.

[0076] In other words, in use of the screening apparatus, oversize material keeps going around blades 42 of rotating members 40 but does not move towards outlet 33 until screen 30 is pivoted such that screen 30 is angled downwards. Gravity then moves the oversize material toward oversize material outlet 33.

[0077] FIGS. 7 and 8 show an alternative preferred screening apparatus according to the invention, generally referred to herein by reference numeral 200. As shown, screening apparatus 200 comprises frame 210, feed hopper 220 mounted at one end of frame 210 and screen 230 pivotally mounted on frame 210 about pivot axis A. In the preferred embodiment shown in FIGS. 7 and 8, screening apparatus 200 is mobile and further comprises tracks 201. Additionally, screening apparatus 200 further comprises conveyor 202 to collect and stockpile screened fines material and conveyor 203 to collect and stockpile screened oversize material.

[0078] As shown in FIGS. 9 to 13c, screen 230 comprises trough 232, five interconnected driven elongate rotating members 240 disposed in an arc along one side of trough 232 and toward the middle of the base of trough 232 and five interconnected driven elongate rotating members 250 disposed in an arc along the other side of trough 232 and toward the middle of the base of trough 232.

[0079] As well as being open at the top for accepting waste material from hopper 220 and open at the base to allow fine material to be discharged, trough 232 is provided with outlet 233 for discharging oversize material. Oversize outlet 233 is shown at the front of trough 32 in the Figures, i.e. at the opposite end of screen 230 to hopper 220. Alternatively, an oversize material outlet (not shown) may be at a side of trough 232, close to the front of the trough, or both, wherein each oversize material outlet independently may be plated off in order to change direction of outlet flow of oversize material.

[0080] Screen 230 is mounted on frame 210 such that at least a portion at least a portion of the top opening of trough 232 is located beneath the outlet end of feed hopper 220 and the elongate rotating members 240, 250 are each independently perpendicular to pivot axis A.

[0081] In order to enable screen 230 to be removed from the screening apparatus for ease of maintenance of the screen, screen is removably mounted to frame 210 such that screen 230 slides with respect to frame 210 for removal therefrom.

[0082] Each of interconnected driven elongate rotating members 240, 250 is identical to rotating member 40 shown in FIG. 3.

[0083] Rotating members 240 run in the opposite direction to rotating members 250, i.e. the shafts of rotating members 240 operate in the clockwise direction and the shafts of rotating members 250 operate in the anti-clockwise direction.

[0084] As shown in FIGS. 14a and 15a, screen 230 may be pivoted along pivot axis A such that screen 230 is angled and mounted with the inlet end of screen 230 higher than the outlet end. FIG. 14a shows screen 230 with the inlet end raised up 7 degrees such that the material remains on the screen for a shorter time and FIG. 15a shows screen 230 with the inlet end raised up 3 degrees such that the material remains on the screen for longer.

[0085] FIGS. 14b and 15b, respectively, show the flow F of material within the screen when the screen is angled as per FIGS. 14a and 15a.

[0086] FIG. 16 shows another alternative preferred screening apparatus according to the invention, generally referred to herein by reference numeral 300. As shown, screening apparatus 300 comprises frame 310, feed conveyor 320 mounted at one end of frame 310 and screen 330 pivotally mounted on frame 310 about pivot axis PA. In the preferred embodiment shown in FIG. 16, screening apparatus 300 and further comprises tracks 301. Additionally, screening apparatus 300 further comprises conveyor 302 to collect and stockpile screened fines material and conveyor 303 to collect and stockpile screened oversize material.

[0087] Feed hopper 321 is attached to frame 310 and may be adjusted by jacking rams 322 in order to pivot screening apparatus 300 on tracks 301.

[0088] Screen 330 is identical to screen 230. As well as being open at the top for accepting waste material from conveyor 320 and open at the base to allow fine material to be discharged, screen 330 is provided with outlet 333 for discharging oversize material. Oversize outlet 333 is shown at the rear of screen 330 in FIG. 16, i.e. at the opposite end of screen 330 to conveyor 320.

[0089] Screen 330 is mounted on frame 310 such that at least a portion at least a portion of the top opening thereof is located beneath the outlet end of feed conveyor 320 and the elongate rotating members are each independently perpendicular to pivot axis PA.

[0090] In order to enable screen 330 to be removed from screening apparatus 300 for ease of maintenance of the screen, screen 330 is removably mounted to frame 310 such that screen 330 slides with respect to frame 310 for removal therefrom.

[0091] Screen 330 may be pivoted along pivot axis PA such that screen 330 is angled and mounted with the inlet end of screen 330 higher than the outlet end. FIG. 16 shows screen 330 with the inlet end raised up such that the material remains on the screen for a shorter time.

[0092] It is to be understood that the invention is not limited to the specific details described herein which are given by way of example only and that various modifications and alterations are possible without departing from the scope of the invention as defined in the appended claims.