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The prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles
This thesis presents the analysis of the path of a ball on the inside of a ball mill for lifter bars with rounded or worn profiles. The model predicts the response of a single ball with particular reference to the balls trajectory after departure from the lifter bar and incorporates the effect of fr...
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| Format: | Thesis |
| Language: | English |
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Department of Mechanical Engineering
2016
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| _version_ | 1867613293396361216 |
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| access_status_str | Open Access |
| author | Milner, Andrew Leigh |
| author2 | Nurick, Gerald N |
| author_browse | Milner, Andrew Leigh Nurick, Gerald N |
| author_facet | Nurick, Gerald N Milner, Andrew Leigh |
| author_sort | Milner, Andrew Leigh |
| collection | Thesis |
| description | This thesis presents the analysis of the path of a ball on the inside of a ball mill for lifter bars with rounded or worn profiles. The model predicts the response of a single ball with particular reference to the balls trajectory after departure from the lifter bar and incorporates the effect of friction, mill rotational speed, lifter height as well as different lifter bar profiles. The out of plane travel of the particles are ignored and hence the system is reduced to a two dimensional problem. A set of experiments were performed on a model perspex mill in order to obtain data by which the theory could be compared. The lifter bar is analysed using a parabolic expression which allows the shape to be changed to model various stages oflifter wear. Two possible formulations are investigated in determining the motion of the particle on the lifter bar. The first formulation assumes the ball to roll on the lifter bar until a limiting friction is reached after which the ball will slide along the lifter. The second formulation considers the ball to have a pure sliding motion on the lifter. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/21702 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:49.949Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Department of Mechanical Engineering |
| publisherStr | Department of Mechanical Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/21702 The prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles Milner, Andrew Leigh Nurick, Gerald N Mechanical Engineering This thesis presents the analysis of the path of a ball on the inside of a ball mill for lifter bars with rounded or worn profiles. The model predicts the response of a single ball with particular reference to the balls trajectory after departure from the lifter bar and incorporates the effect of friction, mill rotational speed, lifter height as well as different lifter bar profiles. The out of plane travel of the particles are ignored and hence the system is reduced to a two dimensional problem. A set of experiments were performed on a model perspex mill in order to obtain data by which the theory could be compared. The lifter bar is analysed using a parabolic expression which allows the shape to be changed to model various stages oflifter wear. Two possible formulations are investigated in determining the motion of the particle on the lifter bar. The first formulation assumes the ball to roll on the lifter bar until a limiting friction is reached after which the ball will slide along the lifter. The second formulation considers the ball to have a pure sliding motion on the lifter. 2016-09-06T14:46:10Z 2016-09-06T14:46:10Z 1997 Master Thesis Masters MSc (Eng) http://hdl.handle.net/11427/21702 eng application/pdf Department of Mechanical Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Mechanical Engineering Milner, Andrew Leigh The prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles |
| thesis_degree_str | Master's |
| title | The prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles |
| title_full | The prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles |
| title_fullStr | The prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles |
| title_full_unstemmed | The prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles |
| title_short | The prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles |
| title_sort | prediction of the outermost trajectory of media in a grinding mill for lifter bars with rounded or worn profiles |
| topic | Mechanical Engineering |
| url | http://hdl.handle.net/11427/21702 |
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