WO2005087378A1 - Grate system - Google Patents
Grate system Download PDFInfo
- Publication number
- WO2005087378A1 WO2005087378A1 PCT/AU2005/000328 AU2005000328W WO2005087378A1 WO 2005087378 A1 WO2005087378 A1 WO 2005087378A1 AU 2005000328 W AU2005000328 W AU 2005000328W WO 2005087378 A1 WO2005087378 A1 WO 2005087378A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- wear plate
- wear
- apertures
- plate
- grating system
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
- B02C17/18—Details
- B02C17/183—Feeding or discharging devices
- B02C17/1835—Discharging devices combined with sorting or separating of material
- B02C17/1855—Discharging devices combined with sorting or separating of material with separator defining termination of crushing zone, e.g. screen denying egress of oversize material
Definitions
- the present invention relates to a grate system for grinding (or tumbling) mills, and in particular for use in autogenous (AG) and semi-autogenous (SAG) grinding mills.
- a tumbling mill is a grinding plant that reduces a charged material by causing the charged material to tumble onto itself. As the material tumbles within the mill, it generates substantial shearing forces. At the same time, as the charged material shifts it generates substantial grinding forces.
- Autogenous grinding (AG) mills and semi-autogenous grinding (SAG) mills are generally large-scale tumbling mills used for pulverising mined ore. The diameter of such mills is large, typically between three and twelve metres. SAG mills differ from AG mills in that they utilise disintegrating members mixed in with the charged material to supplement pulverising action. The disintegrating members are commonly hardened steel balls with a diameter on the order of 100mm.
- the recycling circuit controls the process of selecting and transporting oversized ground material and/ or disintegrating members back into the mill. Recycling circuits may use magnets to retrieve discharged metallic disintegrating members and trommels, vibrating screens, sieves or other mass distinguishing means to select oversize ground material that needs to re-enter the mill for further grinding.
- a particular problem of prior art devices occurs when a small section of grating breaks away, usually no more than two inter-aperture grating portions.
- the grate breakage combines several apertures to create one larger aperture.
- too much insufficiently ground material and disintegrating members are discharged and quickly overwhelm the recycling circuit as well as other subsequent mill processes.
- the result is that the mills must be immediately shutdown for repair.
- SAG mills run in particularly hostile environments, where grate breakage is the most prevalent cause of unscheduled shutdown and repair.
- the present invention overcomes at least one of the deficiencies of the prior art liners by providing an improved grate system.
- the invention consists of a grating system for a grinding mill comprising a base plate and at least one wear plate, wherein said wear plate is removably secured to said base plate, said wear plate having a plurality of apertures in said wear plate that substantially overlie a corresponding plurality of apertures in said base plate such that pulverised material may pass through said apertures, and wherein said base plate and said corresponding plurality of apertures are arranged such that said grinding mill may continue operation with portions of said wear plate broken away.
- said base plate is at least as thick as said wear plate.
- said apertures in said wear plate are substantially the same size as said corresponding apertures in said base plate.
- said grating system has at least one pad disposed on a wear surface of said wear plate and adjacent to at least one of said apertures of said wear plate.
- said pad is an anti-peening pad.
- said wear plate and at least one of said pads are fabricated from dissimilar materials.
- At least one of said pads is affixed to said wear plate by fasteners.
- at least one of said pads is previously fabricated and then subsequently integrated into said wear plate during the fabrication of said wear plate.
- said base plate and said wear plate are fabricated from dissimilar materials.
- said base plate has a Brinell hardness between 500 - 700 bn.
- said wear plate has a Brinell hardness between 300 - 400 bn.
- said wear plate includes at least one lifter comprising a longitudinally elongate raised portion.
- said wear plate includes at least one lifting lug.
- a layer of resilient material is disposed between said wear plate and said base plate.
- the invention consists of a grating system comprising a wear plate, wherein a plurality of apertures allow ground material to pass through said wear plate, wherein at least one anti-peening pad is disposed on a wear surface of said wear plate adjacent to at least one of said apertures, and said wear plate and said anti-peening pad are fabricated from dissimilar materials.
- said anti-peening pad is affixed to said wear plate by fasteners.
- said anti-peening pad is fabricated separately and then subsequently integrated into said wear plate.
- Fig 1 is an exploded perspective view of a split grate system in accordance with an embodiment of the present invention.
- Fig 2 is an enlarged perspective view of the split grate system shown in Fig 1.
- Fig 3 is an enlarged partial perspective view of the comer of the split grate system of Fig. 1 in an assembled configuration.
- Fig 4 is a cross-sectional schematic view of the split grate system through lines IN - IV of Fig. 3.
- split grate 1 comprises base plate 2 and wear plate 3.
- Base plate 2 is removably secured to a grinding mill (not shown) through base holes 4.
- Wear plate 3 is removably secured to base plate 2 through wear holes 6.
- Split grate 1 allows pulverised material to discharge out of the mill through apertures 7 in wear plate 3 and then throTigh corresponding apertures 8 in base plate 2. Apertures 7 of wear plate 3 are substantially aligned with apertures 8 in base plate 2.
- Wear surface 9 preferably has at least one lifter 12 that acts to lift the charged materiaJl as the grinding mill rotates.
- Lifter 12 preferably consists of a longitudinally raised portion along wear surface 9 of wear plate 3.
- Wear plate 3 may also have at least one lifting lug 13 disposed centrally on wear surface 9 for handling by a relining machine not shown.
- Wear plate 3 and base plate 2 are preferably constructed from dissimilar materials, whearein base plate 2 has a higher hardness than wear plate 3.
- base plate 2 has a Brknell hardness in the order of 500 - 700 bn, whereas wear plate 3 may preferably be in the o_rder of 300 - 400 bn.
- Base plate 2 functions as a structural support and is less subject to impact fracturing and erosion than wear plate 3.
- hardness of base plate 2 may be maximised with less concern for decreases in ductility.
- some degree of ductility is desirable in wear plate 3 to minimise fracturing and erosion of the wear plate and the disintegrating members whilst the grinding mill operates.
- Suitable materials would be _F34 - 38 for base plate 2 and chrome molybdenum for wear plate 3. In some applications, for example where frequent grate breakages are expected, it may be preferable to fabricate base plate 2 and wear plate 3 from materials having similar characteristics because base plate 2 will be expected to withstand impacts after portions of wear plate 3 break away.
- thickness of base plate 2 is preferably equal to or greater than wear plate 3. Relative thicknesses of the plates may be varied to improve performance according to wear rate information of a particular milling process.
- Apertures 7 in wear plate 3 substantially overlie apertures 8 in base plate 2.
- the thickness of base plate 2 is advantageously chosen such that the plate is strong enough to withstand the impact of operating the grinding mill (not shown) without wear plate 3, as is the case when portions of wear plate 3 break away.
- Apertures 8 in base plate 2 are fabricated with substantially similar sizes to that of apertures 7 in wear plate 3, so that the discharge characteristics of split grate 1 are substantially constant over its life, even when apertures 7 wear wider due to erosion or when portions of wear plate 3 break away suddenly.
- pads 11 are disposed adjacent to apertures 7 on wear surface 9.
- the advantages of pads 11 are two fold. First, they act as anti-peening pads to eliminate problems that occur with prior art grate systems where the apertures peen over after a period of operation, normally by the fourth week. This reduces the aperture size by 25%, thus restricting mill throughput. In the prior art, restricted throughput typically lasts from the fourth through the eighth week before the aperture wears large enough to correct for the peening. In other instances, pads 11 act to prevent the apertures from peening wider.
- the extra material of pads 11 is sacrificial, thereby lengthening the overall amount of mill operating time before eroding the effective thickness of wear plate 3 and size of apertures 7.
- the effective shape and size of apertures 7 are less susceptible to deformations.
- wear plate 3 has a longer useful life and exhibits more uniform discharge characteristics over that life.
- pads 11 may comprise anti-peening pads that are cast separately to wear plate 3.
- the separately cast anti-peening pads may then be affixed to, or alternatively cast into, wear plate 3.
- the separately cast anti-peening pads may be cast from a material dissimilar to that of wear plate 3. This allows the anti-peening pads to be made of materials more suitable, for example harder and more wear resistant, than what is suitable or possible for the larger wear plate 3.
- Further embodiments may vary the characteristic of pads 11 to suit the particular milling process and may also vary with location on wear plate 3. For example, height, width, curvature and relief angle of pads 11 may be adapted for different ground material types, whether disintegrating members are used, whether there is a recycling circuit, and the relative size and shape of apertures 7.
- the wear plate may be removably affixed to the base plate by a fastening means other than bolting through wear holes.
- the wear holes and the base holes may vary in number and arrangement.
- a plurality of wear plates may be affixed to a single base plate, each of which may iave varying characteristics.
- the base plate may v ary in thickness relative to the wear plate.
- the thickness of the base plate would toe equal to or greater than the thickness of the wear plate.
- a layer of resilient material for example a 6 mm rubber gasket, may be disposed between the wear plate and the base plate.
- Materials, configuration, and thicknesses of the plates may be optimised to the specific characteristics and requirements of a particular milling process.
Landscapes
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Crushing And Grinding (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2005221228A AU2005221228B2 (en) | 2004-03-12 | 2005-03-09 | Grate system |
NZ550495A NZ550495A (en) | 2004-03-12 | 2005-03-09 | Grate system for grinding mill |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2004901301 | 2004-03-12 | ||
AU2004901301A AU2004901301A0 (en) | 2004-03-12 | Grate System | |
AU2004904381A AU2004904381A0 (en) | 2004-08-04 | Grate System | |
AU2004904381 | 2004-08-04 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2005087378A1 true WO2005087378A1 (en) | 2005-09-22 |
Family
ID=34975385
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AU2005/000328 WO2005087378A1 (en) | 2004-03-12 | 2005-03-09 | Grate system |
Country Status (2)
Country | Link |
---|---|
NZ (1) | NZ550495A (en) |
WO (1) | WO2005087378A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2011130781A1 (en) * | 2010-04-19 | 2011-10-27 | Vulco S.A. | A wear plate system, arrangement and method |
US9415395B2 (en) | 2010-04-19 | 2016-08-16 | Vulco S.A. | Wear plate fastening system, arrangement and method |
WO2018094544A1 (en) * | 2016-11-28 | 2018-05-31 | Universidad De Santiago De Chile | Grid with modified groove inclination |
WO2021136866A1 (en) * | 2019-12-30 | 2021-07-08 | Metso Outotec Finland Oy | A method of maintaining grate of grinding mill and maintenance arrangement |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3776477A (en) * | 1971-01-15 | 1973-12-04 | Smidth & Co As F L | Sandwich diaphragm for mill |
SU1230682A1 (en) * | 1984-04-26 | 1986-05-15 | Bogudlov Feliks A | Unloading grate for tumbling barrel |
SU1719006A1 (en) * | 1989-09-27 | 1992-03-15 | В.Ф.Шемарин | Device for conjuring tricks |
WO1996000127A1 (en) * | 1994-06-24 | 1996-01-04 | Slegten Societe Anonyme | Device for holding standard cast grates of existing partitions frames in tube mills |
US5570844A (en) * | 1992-10-28 | 1996-11-05 | Slegten S.A. | Method for tubular rotary ball mill or mill with similar grinding instruments |
-
2005
- 2005-03-09 WO PCT/AU2005/000328 patent/WO2005087378A1/en active IP Right Grant
- 2005-03-09 NZ NZ550495A patent/NZ550495A/en not_active IP Right Cessation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3776477A (en) * | 1971-01-15 | 1973-12-04 | Smidth & Co As F L | Sandwich diaphragm for mill |
SU1230682A1 (en) * | 1984-04-26 | 1986-05-15 | Bogudlov Feliks A | Unloading grate for tumbling barrel |
SU1719006A1 (en) * | 1989-09-27 | 1992-03-15 | В.Ф.Шемарин | Device for conjuring tricks |
US5570844A (en) * | 1992-10-28 | 1996-11-05 | Slegten S.A. | Method for tubular rotary ball mill or mill with similar grinding instruments |
WO1996000127A1 (en) * | 1994-06-24 | 1996-01-04 | Slegten Societe Anonyme | Device for holding standard cast grates of existing partitions frames in tube mills |
Non-Patent Citations (2)
Title |
---|
DATABASE WPI Week 198701, Derwent World Patents Index; Class P41, AN 1987-005902 * |
DATABASE WPI Week 199305, Derwent World Patents Index; Class P41, AN 1993-044034 * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2011130781A1 (en) * | 2010-04-19 | 2011-10-27 | Vulco S.A. | A wear plate system, arrangement and method |
CN102947004A (en) * | 2010-04-19 | 2013-02-27 | 乌尔可公司 | A wear plate system, arrangement and method |
CN102947004B (en) * | 2010-04-19 | 2014-11-05 | 乌尔可公司 | Grinding miller,wear plate for a grinding mill discharge head, and manufacturing and installing method of wear plate |
US9375722B2 (en) | 2010-04-19 | 2016-06-28 | Vulco S.A. | Wear plate system, arrangement and method |
US9415395B2 (en) | 2010-04-19 | 2016-08-16 | Vulco S.A. | Wear plate fastening system, arrangement and method |
EA025446B1 (en) * | 2010-04-19 | 2016-12-30 | Вулко С.А. | Wear plate for a grinding mill discharge head and method of manufacturing the same |
WO2018094544A1 (en) * | 2016-11-28 | 2018-05-31 | Universidad De Santiago De Chile | Grid with modified groove inclination |
WO2021136866A1 (en) * | 2019-12-30 | 2021-07-08 | Metso Outotec Finland Oy | A method of maintaining grate of grinding mill and maintenance arrangement |
Also Published As
Publication number | Publication date |
---|---|
NZ550495A (en) | 2010-06-25 |
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