METHOD AND DEVICE FOR SEPARATION OF LONG PARTS

Abstract

A device and a method for the separation of elongated parts (long parts) from bulk materials. The device comprises a conveying device (1), a deflecting device (2) and a rake with webs (4) being oriented longitudinally to the conveying direction. According to the method, the bulk material is transported on the conveying device (1), and then long parts (10) are oriented by means of a deflecting device (2) transversely to the conveying direction. After passing through the deflecting device (2), the transversely oriented long parts are transferred to the rake (4) and discharged as coarse materials (7). Compact parts (11) fall through this rake and thus end up in the fine material (6).

Claims

1. A long part separator for bulk material (10, 11) having long parts (10) and compact parts (11) comprising: a conveying device (1) for conveying the bulk material (10, 11) along a conveying direction (F) and a rake (4), which is situated behind the conveying device (1) when seen along the conveying direction (F) of the conveying device (1), wherein the rake (4) comprises a plurality of interspaces (40), having in a first direction (R1) a clear length (y) and in a second direction (R2) lying transversely to the first direction (R1) a clear width (x), and wherein the long part separator furthermore comprises a deflecting device (2) arranged between the conveying device (1) and the rake (4), which is suitable for orienting the long parts (10) at an angle of 45 to 90, or substantially transversely, to the first direction (R1) or to the clear length (y) of the interspaces (40).

2. The long part separator according to claim 1, wherein the first direction (R1) along which the interspaces (40) extend by the clear length (y) runs parallel to the conveying direction (F).

3. The long part separator according to claim 1, wherein the deflecting device (2) is designed as an obstacle for the long parts, such that long parts (10) oriented longitudinally to the conveying direction (F) strike against the deflecting device (2) substantially at the front end.

4. The long part separator according to claim 1, wherein the deflecting device (2) comprises a plate arranged transversely to the conveying direction (F), and wherein the plate is arranged movably relative to the conveying device (1), in particular in a swivelling or swinging manner; or wherein the plate is arranged firmly relative to the conveying device (1).

5. The long part separator according to claim 4, wherein the horizontal distance (S) between the plate and the front end (41) of the conveying device (1) is smaller than four times the clear width (x) of the rake (4), preferably smaller than twice the clear width (x) of the rake (4).

6. The long part separator according to claim 1, wherein the deflecting device (2) comprises a chute (42), wherein the chute (42) is adjacent to the front end (41) of the conveying device (1), and wherein the chute (42) is preferably curved or concavely rounded or inclined at an angle to the conveying surface of the conveying device.

7. The long part separator according to claim 1, wherein the rake (4) is coupled to a vibration exciter; and/or a baffle plate (3) is installed between the deflecting device (2) and the rake (4); and/or the conveying device (1) conveys material by vibrating.

8. A method for separating long parts (10) from bulk material, especially with a long part separator according to claim 1, wherein the bulk material is conveyed via a conveying device (1) and transferred from this to a rake (4), wherein the rake (4) comprises a plurality of interspaces (40), having in a first direction (R1) a clear length (y) and in a second direction (R2) lying transversely to the first direction (R1) a clear width (x), and wherein the long parts are oriented at an angle of 45 to 90, or substantially transversely to the first direction (R1) with the clear length (y) of the interspaces (40) by a deflecting device (2) situated between the conveying device (1) and the rake (4).

9. The method according to claim 8, wherein the long parts (10) to be separated have a diameter (d) which is smaller than the clear width (x) of the rake (4).

10. The method according to claim 8, wherein the long parts (10) to be separated have a length (L) which is greater than twice the clear width (x) of the interspace (40) of the rake (4).

11. The method according to claim 8, wherein the bulk material has already been classified before being placed on the conveying device (1) such that the diameter (d) of the long parts (10) is less than the clear width (x) of the rake (4).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Preferred embodiments of the invention shall be described in the following with the aid of the drawings, which merely serve as an explanation and should not be interpreted in limiting manner. The drawings show:

[0039] FIG. 1 a schematic view of a device according to a first embodiment seen from the side and from above;

[0040] FIG. 2 a schematic view of a triangular deflecting device

[0041] FIG. 3 a schematic view of a conveying device with a chute and a baffle plate

[0042] FIG. 4 a schematic view of a conveying device designed as a sieve

[0043] FIG. 5 a schematic view of a three-stage long part separator

[0044] FIG. 6 a schematic view of a conveying device designed as a conveyor belt

[0045] FIG. 7 a schematic view of a long part separator separating by particle diameter in an upper stage, and by particle length in a stage situated underneath.

[0046] FIG. 1 shows a first exemplary embodiment of the device according to the invention for separating long parts with diameter d from compact parts, likewise with diameter d, from a bulk material with grain size distribution d.sub.min<d<d.sub.max. The long parts (10) are preferably defined as being parts having a length L>2 d. Parts with preferably L<2 d are compact parts (11). The bulk material is transported by means of the conveying device (1), which preferably vibrates in a linear manner, wherein the long parts (10) have a tendency to orient themselves in the conveying direction. The deflecting device (2) in this case is a plate installed transversely to the conveying direction behind the front end of the conveying device. Whereas compact parts (11) drop across the front end of the conveying device through the rake (4) into the fine material (6), long parts oriented along the conveying direction strike against the deflecting device (2), and are turned transversely to the conveying direction until they drop across the front end of the conveying device transversely onto the rake (4), slide through its webs, and thus are ejected into the coarse material (7). The deflecting device (2) sketched in FIG. 1 is generally a steel plate, which is provided e.g. at the front end with a wear protection (such as rubberizing) The deflecting device can be modified in various ways, e.g., by a triangular design as depicted in FIG. 2. In this way, the long parts are lifted somewhat at the front end and are therefore easier to move transversely. Preferably, the deflecting device sketched in FIG. 1 is installed such that it can deflect in the event of a possible material build-up (e.g., suspended in a pendulum-like manner as sketched in FIG. 1). When the conveying device is very wide, the deflecting device is advantageously designed in the form of individual segments placed next to each other. To assist in the deflection, the front end of the deflecting device sketched in FIG. 1 may also have a corrugated sheet or zigzag design (when seen from above). Typical dimensions of this embodiment of the device according to the invention are: [0047] d.sub.min<d<d.sub.max<x<L/2 [0048] D=0.2x . . . 2x [0049] S=x . . . 2.5x [0050] H=1.5x . . . 2.5x [0051] T=0.5x . . . x

[0052] Here, x is the clear width of the rake. Experiments have shown that, with typical dimensions, good separator results are to be expected for particles with length L>3x and very good results for particles with L>5x.

[0053] FIG. 3 shows a second exemplary embodiment of the device according to the invention. Vibrating conveyors are considered primarily as the conveying device (1), but also vibrating sieves, for example. In the embodiment depicted in FIG. 3, the ejection region of the conveying device is configured as a curved chute (42), so that an ideally point-like contact surface is produced between the long parts (10) and the chute, which favours the transverse positioning of the long parts by the deflecting device (2). The chute is preferably curved in the form of a quarter circular arc segment with radius R. It has proven to be especially favourable to select the radius R depending on the length L of the long parts being separated as follows: L/2<R<2L. On the chute at the front end, long parts striking against the deflecting device rotate about the contact point with the chute and then slide off transversely to the conveying direction. Experiments have shown that it is advantageous to provide a baffle plate (3) after the ejection, which prevents short, not yet fully transversely oriented long parts from getting headfirst into the rake and slipping through the webs of the rake. The baffle plate (3) is installed at an acute angle to the horizontal, preferably at an angle <30. Long parts not yet fully oriented transversely to the conveying direction strike against this with their head end, are slowed down and become rotated entirely transversely to the conveying direction by sliding of the rear end on the curved chute and are thus transferred to the rake. The rake (4), if stationary (as shown in FIG. 3), is installed at an angle of preferably 45 . . . 70. In FIG. 3, the conveying device (1) is separate from the baffle plate (3) and the rake (4). It may also be advisable to join these three elements together, especially when the conveying device is a vibrating conveyor and the vibrations also serve to convey the material across the baffle plate and the rake. In these cases, the angles and may be relatively acute. If the rake is in linear vibration, it may even deliver in a slightly rising manner, in which case becomes negative.

[0054] The device according to the invention may, as sketched in FIG. 4, be mounted directly on a sieve machine, including a sieve machine with multiple decks. It is especially easy to convert a conventional finger or rod sieve machine (sizer), in which the sieve elements are already configured as a rake. Such sieve machines often have several stages for the circulation of the material, and may therefore be easily retrofitted with a deflecting device (2) as sketched in FIG. 1 and, if needed, also with a baffle plate (3) in order to implement the invention (FIG. 5). The conveying device may also be a conveyor belt (FIG. 6), which is combined with the deflecting device (2) depicted in FIG. 1.

[0055] Our experiments have shown that a stationary rake can also be used, across which the long parts slide by gravity, as depicted in FIG. 3. It has proven to be advantageous if the rake actively delivers the long parts, e.g., by vibrating. Therefore, it will advantageously be combined with the conveying device as a unit, provided the latter is itself vibrating (e.g., a vibrating conveyor).

[0056] In order to carry out the method according to the invention, it is advantageous to first sort the bulk material in terms of grain size so that all parts, i.e., both the long parts (10) and the compact parts (11), have a maximum diameter d.sub.max which is less than the clear width x of the rake (4). In order to accomplish this free of jamming, the bulk material is first sieved, e.g., on a conventional finger sieve with clear width x, wherein both the long parts (10) with diameter d and the compact parts (11) with diameter d get into the fine material. This fine material is then separated by means of the device according to the invention at the clear width x of the rake (4) such that the long parts (10) are discharged in the coarse material and the compact parts (11) in the fine material. Advantageously, this method is implemented in the combination device (1) sketched in FIG. 7. This consists of the following elements: a coarse grate (20) (e.g., a finger sieve or rod sizer) with clear width x=1.7 d, a coarse grate chute (20a), a fine grate (21) with clear width x*=0.7 d (such as a finger sieve or rod sizer), a fine sieve chute (21a), a deflecting device (2), a baffle plate (3), and a rake (4) with clear width x=1.7 d. Parts (14) (15) with grain size <0.7 d drop, regardless of their length, through the coarse grate with clear width x and through the fine grate with clear width x*. Parts (12) (13) with grain size >1.7 d, regardless of their length, are discharged via the coarse grate chute (20a) in the coarse material of the coarse grate. Parts with a grain size between 0.7 d and 1.7 d (10) (11) fall through the coarse grate, then migrate across the fine grate and reach the rake (4) via the fine grate chute (21a) and the deflecting device (2). Here, they are separated according to their length.

[0057] The webs of the rake (4) are preferably parallel rods with a circular or triangular cross-section. However, one may also use webs tapering in the conveying direction, e.g., wedge-shaped webs, or also webs flattened on top. Our experiments have confirmed the rule of thumb, derived from theoretical considerations, that for a good separation of compact parts (11) with diameter d, the long parts (10) must meet the following conditions: [0058] d<x [0059] L>2(x+D)

[0060] where d is the diameter of the long parts and L is their length, x is the clear width of the rake, and D is the width of the webs of the rake. In the case of interspaces (40) not being rectangular as seen from above (but instead wedge-shaped for example), and thus have a variable gap dimension, the clear width (x) is the largest gap dimension, i.e., the largest spacing, between neighbouring webs.

LIST OF REFERENCE SYMBOLS

[0061] 1 Conveying device [0062] 2 Deflecting device [0063] 3 Baffle plate [0064] 4 Rake [0065] 4 Fine material [0066] 5 Coarse material [0067] 6 Long parts [0068] 7 Compact parts [0069] 10, 11 Bulk material [0070] 20 Coarse grate [0071] 20a Coarse grate chute [0072] 21 Fine grate [0073] 21a Fine grate chute [0074] 40 Interspaces of rake webs [0075] 41 Front end of conveying device [0076] 42 Chute [0077] D Diameter of rake webs [0078] d Diameter of bulk material particles [0079] L Length [0080] F Conveying direction [0081] R1 First direction [0082] R2 Second direction [0083] S Horizontal distance between the front end of the conveying device and the deflecting device [0084] T Vertical distance between the lower edge of the deflecting device and the front end of the conveying device [0085] H Vertical distance between the lower edge of the deflecting device and the rake or baffle plate (if present) [0086] x Clear width (gap size) of the interspaces of the rake [0087] y Clear length of the interspaces of the rake