Abstract
A lifting wall arrangement at an end wall of a drum mill, having a plurality of segments which are removably installable on the end wall. Each segment includes an inner wall and an opposing outer wall. At least one lifting blade is arranged on the outer wall, such that the outer wall, the lifting blade and the inner wall define a discharge channel leading to a discharge cone. The inner wall forms a part of a sieving wall in the drum mill. Each segment constitutes an integrated unit adapted to be installed on the end wall. Other embodiments include a segment of a lifting wall arrangement and a drum mill having a lifting wall arrangement.
Claims
1. A lifting wall arrangement configured to be installed at an end wall of a drum mill, having a plurality of segments which are removably installable on the end wall, wherein each segment comprises an inner wall and an opposing outer wall, wherein at least one lifting blade is arranged on said outer wall, such that the outer wall, the lifting blade and the inner wall define a discharge channel leading to a discharge cone, and wherein each segment constitutes an integrated unit adapted to be installed on the end wall, wherein the integrated unit is adapted to be attached to the end wall from the outside of the drum mill, wherein the integrated unit comprises first mounting means adapted to, through mounting holes in the end wall, interact with complementary second mounting means installed from the outside of the drum mill, and wherein the first mounting means comprises a fastener body insert arranged in a recess or a bore in the outer wall of the integrated unit facing the end wall.
2. A lifting wall arrangement according to claim 1, wherein the fastener body insert constitutes a threaded bushing or sleeve.
3. A lifting wall arrangement according to claim 1, wherein the inner wall of the integrated unit comprises sieving openings.
4. A lifting wall arrangement according to claim 1, wherein the inner wall and the outer wall of the segment are connected by chemical bonding or mechanical connection and thereby form an integrated unit.
5. A lifting wall arrangement according to claim 4, wherein the chemical bonding comprising one of the following vulcanization or gluing.
6. A lifting wall arrangement according to claim 4, wherein the mechanical connection comprising one of the following bolting or riveting.
7. A lifting wall arrangement according to claim 1, wherein each segment comprises polymer, metal, ceramic, or any combination thereof.
8. A lifting wall arrangement according to claim 1, wherein each segment is arcuate.
9. A segment of a lifting wall arrangement configured to be installed at an end wall of a drum mill, wherein the segment is removably installable on the end wall, wherein at least one lifting blade is arranged on said outer wall, such that the outer wall, the lifting blade and the inner wall define a discharge channel leading to a discharge cone, and wherein the segment constitutes an integrated unit adapted to be installed on the end wall wherein the segment is adapted to be attached to the end wall from the outside of the drum mill wherein the integrated unit comprises first mounting means adapted to, through mounting holes in the end wall, interact with complementary second mounting means installed from the outside of the drum mill, and wherein the first mounting means comprises a fastener body insert arranged in a recess or a bore in the outer wall of the integrated unit facing the end wall.
10. A segment according to claim 9, wherein the inner wall comprises sieving openings.
11. A drum mill, wherein it comprises a lifting wall arrangement according to claim 1.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) For fuller understanding of the present invention and further objects and advantages of it, the detailed description set out below should be read together with the accompanying drawings, in which the same reference notations denote similar items in the various diagrams, and in which:
(2) FIG. 1 schematically illustrates a drum mill comprising a lifting wall arrangement according to an embodiment of the invention;
(3) FIG. 2 schematically illustrates a lifting wall arrangement according to an embodiment of the invention;
(4) FIG. 3a-f schematically illustrates segments of a lifting wall arrangement according to various embodiments of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
(5) FIG. 1 shows a part of a drum mill comprising a lifting wall arrangement according to an embodiment of the invention. The drum mill comprises a mill shell 1 and two end walls, an input end wall (not shown) and a discharge end wall 2. The mill shell 1 and the end walls 2 form a substantially cylindrical compartment called the grinding chamber 3. The drum mill rotates around a rotation axis A. The mill shell 1 is internally lined with a lining 4 of some wear-resistant material, for example an elastomer. A discharge trunnion 5 extends centrally from the discharge end wall 2. Inside the drum mill, at the discharge end wall 2, a rotating lifting wall arrangement 8 is provided. The lifting wall arrangement 8 is adapted to lift the grinded material inside the grinding chamber and lead it out of the drum mill through the discharge trunnion 5. The lifting wall arrangement 8 comprises a central discharge cone 9 and a plurality of segments 10 radially arranged circumferentially surrounding the discharge cone 9. The segments 10 are attached to the end wall 2 and the central discharge cone 9 is arranged in fluid communication with the discharge trunnion 5. The segments 10 may also be called pulp lifters. The lifting wall arrangement 8 is further described in FIG. 2.
(6) FIG. 2 shows a cut section of a lifting wall arrangement 8 according to an embodiment of the invention. The lifting wall arrangement 8 is installed at an end wall 2 of the drum mill as described in FIG. 1. The lifting wall arrangement 8 has a plurality of segments 10 which are removably installable on the end wall. The segments are designed as sections of a circle and together form a circle, circumferentially surrounding the central discharge cone 9 of the lifting wall arrangement 8. According to this embodiment the lifting wall arrangement 8 comprises an outer circle of segments 10A, an intermediate circle of segments 10B and an inner circle of segments 10C. The circles of segments 10A, 10B, 10C and the discharge cone 9 together form a circular disk. Each segment 10 comprises an inner wall 10:1 and an opposing outer wall 10:2, wherein at least one lifting blade 11 is arranged on said outer wall 10:2, such that the outer wall, the lifting blade and the inner wall define a discharge channel 12 leading to the central discharge cone 9. The segment outer wall 10:2 is abutting the end wall 2 of the drum mill and the segment inner wall 10:1 forms a part of a sieving wall 13 facing the grinding chamber 3 in the drum mill. Each segment 10 constitutes an integrated unit adapted to be installed on the end wall 2.
(7) With reference to FIG. 1 the segments 10 in the outer circle, called the outer segments 10A, comprise sieving openings 14 in the inner wall 10:1. The inner walls 10:1 of the outer segments 10A thus constitute grates. The inner walls 10:1 of the intermediate segments 10B and the inner segments 10C are so called blind grates, without sieving openings. When the outer segments 10A are in a bottom position during rotation of the mill, grinded material (pulp) will enter through the sieving openings 14 into the discharge channels 12 of the segments 10A, 10B, 10C. As the lifting wall arrangement 8 rotates and the outer segments 10A reach a top position, the pulp will be lead through the discharge channels 12 in the intermediate 10B and inner segments 10C to the central discharge cone 9 and out of the drum mill. Alternatively, all segments 10A, 10B, 10C can comprise sieving openings 14 in the inner wall 10:1.
(8) As shown in the enlargement view in FIG. 2 the segments 10 constituting integrated units are suitably installed on the end wall 2 by means of first mounting means 20 which interact with complementary second mounting means 30 installed from the outside of the drum mill. The first mounting means 20 and the second mounting means 30 thus interact through mounting holes 35 in the end wall 2 of the mill drum.
(9) FIGS. 3a-3f show segments 10 of a lifting wall arrangement 8 according to various embodiments of the invention. The segments 10 are configured as described in relation to FIG. 2 and thus comprise an inner wall 10:1 and an outer wall 10:2 and at least on lifting blade 12 integrated as a one-piece unit. The segments may be formed as integrated units by chemical bonding, mechanical connection or be configured to achieve a shape-bound connection with one another. Vulcanizing, casting, welding, gluing, bolting, riveting or any other known joining methods, depending on the selected combination material. The segments 10 may comprise elastic polymers, ceramic materials, cemented carbides steel alloys and/or metal or combinations thereof. The segments 10 may alternatively comprise a compound from any of the above mentioned materials. The segments specifically comprise wear-resistant materials such as a steel alloys suitable to be used in an iron ore mill.
(10) FIG. 3a shows a segment 10 configured as a section of a circle which comprises three lifting blades 11. One lifting blade 11a, 11c is radially arranged at each side of the segment 10 facing an adjacent segment and one lifting blade 11b is arranged there between. The lifting blades 11 are thus arranged such that two discharge channels are formed 12a, 12b. When two such segments 10 are arranged adjacent each other, one lifting blade of the first segment will abut a lifting blade of the second segment. The inner wall 10:1 comprises sieving openings 14 for the entry of grinded material into the discharge channels. The inner wall 10:1 is thus a grate. The discharge channels 12 may also be denominated pulp-lifting chambers. The segment according to FIG. 3a is suitably an outer segment 10A adapted to be arranged along the periphery of the lifting wall arrangement 8.
(11) FIG. 3b shows the outer wall 10:2 of the segment 10 in FIG. 3a. With reference also to the enlargement view in FIG. 2 the outer wall 10:2 comprises first mounting means 20 in the form of fastener bodies 21 such as holding inserts arranged in recesses or bores in the outer wall. The segment 10 is adapted to be positioned such that the fastener bodies 21 are in line with mounting holes 35 in the end wall 2. Second mounting means 30 may thereby be installed from the outside of the drum mill such that it interacts with the first mounting means 20. The fastener bodies 21 are suitably threaded bushings or sleeves that can be tubular. The second mounting means 30 are suitably threaded bolts 31 or similar means interacting with the threaded bushings or sleeves. As shown in the enlargement in FIG. 2 a washer 36 can be placed between the head of the bolt 31. Also a rubber washer 37 can be arranged between the washer 36 and the outside of end wall 2 of the drum mill.
(12) FIG. 3c shows an arcuate segment 10 comprising two lifting blades 11a, 11c. The lifting blades are arranged such that a discharge 12a channel is formed in the middle of the segment and such that the segment has open ends towards adjacent segments. This way, when two such segments 10 are arranged adjacent each other a discharge channel 12a will be formed between the two segments. The inner wall comprises sieving openings 14 for the entry of grinded material into the discharge channels 12. The segment 10 according to FIG. 3c may be an outer segment 10A adapted to be arranged along the periphery of the lifting wall arrangement 8.
(13) FIG. 3d shows an arcuate segment 10 comprising one lifting blade 11a. The lifting blade 11a is arranged centrally on the segment such that the segment has open ends towards adjacent segments. This way, when two such segments are arranged adjacent each other a discharge 12a channel will be formed between the two segments. The segment has an inner wall 10:1 without sieving openings, a so called blind grate. The segment is suitably an inner segment 10C adapted to be arranged in direct connection with the central discharge cone 9 of the lifting wall arrangement 8. FIGS. 3e and 3f show segments 10 configured as sections of a circle comprising inner walls 10:1 without sieving openings.
(14) FIG. 3e shows a segment 10 comprising two lifting blades 11a, 11c. The lifting blades 11a, 11c are arranged such that a discharge channel 12 is formed in the middle of the segment and such that the segment has open ends towards adjacent segments. The segment is suitably an intermediate segment 10B. FIG. 3f comprises three lifting blades 11a, 11b, 11c. One lifting blade 11a, 11c is arranged at each side of the segment facing an adjacent segment and one lifting blade 11b is arranged there between. The lifting blades are thus arranged such that two discharge 12a, 12b channels are formed. The segment is suitably an intermediate segment 10B.
(15) The foregoing description of the preferred embodiments of the present invention is provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to restrict the invention to the variants described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order best to explain the principles of the invention and its practical applications and hence make it possible for specialists to understand the invention for various embodiments and with the various modifications appropriate to the intended use.
