The invention relates to a liner fastener for fastening a liner to a rotatable shell of a grinding mill, and more particularly, but not exclusively, to a fastening device for securing internal liners to mills typically used in the mining industry, such as autogenous (AG), semi-autogenous (SAG), ball, pebble and rod mills.
Mills typically used in the mining industry often employ a lining of heavy steel, rubber or composite liner segments secured to the inside of the mill using liner bolts. One such previously known arrangement is shown in
During operation of a mill, the liners and liner bolts wear and deform, and the clearances around the liner bolts become filled with compacted ore fines. As a result, the liner bolts are typically very difficult to remove when the liners require replacement, making liner bolt removal one of the most time consuming operations undertaken when replacing liners.
The applicant has identified that there is a problem in that to remove a conventional liner, the liner bolts must first be removed by driving them back through their original entry path. Typical methods to drive liner bolts back comprise manually operated sledge hammers, and more commonly reciprocating power hammers suspended from a crane (such as the RME Thunderbolt hammer) or mounted to a mobile vehicle (such as a modified skid-steer loader).
Regardless of the method chosen, the process of removing liner bolts is a time-consuming task, and may result in injury to workers and/or damage to the mill shell as a result of the aggressive tools used.
Examples of the invention seek to replace conventional liner bolts with an improved liner fastener which does not need to be driven back through its original entry path when replacing liners, thereby overcoming or at least alleviating the above-mentioned disadvantages.
In accordance with one aspect of the present invention, there is provided a liner fastener for fastening a liner to a rotatable shell of a grinding mill, the fastener comprising a flexible tie, a retainer fitting for retaining the fastener relative to an aperture of the liner, and a tensioning fitting, wherein the flexible tie is adapted to be inserted into the liner aperture and a corresponding mounting aperture in the shell and fed through such that the retainer fitting becomes anchored within a socket formed in the aperture of the liner, and the tensioning fitting is adapted to be fitted to an end portion of the flexible tie protruding outside the shell to bear against the shell and to maintain tension in the fastener to thereby fasten the liner to the shell.
Preferably, the flexible tie is adapted to be inserted from an inside of the liner. Alternatively, the flexible tie may be inserted from outside the liner.
Preferably, the flexible tie is in the form of a length of wire rope.
Preferably, the retainer fitting is in the form of a wedge collar and barrel assembly. Alternatively, the flexible tie may be anchored to the retainer fitting by way of a swaging process.
In a preferred form, the retainer fitting is dimensioned so as to prevent the retainer fitting from passing through the liner aperture.
In a preferred form, the retainer fitting is dimensioned so as to prevent lateral movement of the liner relative to the mill shell.
Preferably, the tensioning fitting is in the form of a wedge collar and barrel assembly, the wedge collar being arranged within a tapered interior of the barrel to permit one-way movement of said assembly along the flexible tie.
In accordance with another aspect of the present invention, there is provided a liner fastener when used to fasten a liner to a rotatable shell of a grinding mill, the fastener comprising a flexible tie, a retainer fitting, and a tensioning fitting, wherein the flexible tie is inserted into a liner aperture and a corresponding mounting aperture in the shell, the retainer fitting is anchored within a socket formed in the liner aperture to anchor the fastener against further displacement through the liner aperture, and the tensioning fitting is fitted to an end portion of the flexible tie protruding outside the shell, the tensioning fitting bearing against the shell to maintain tension in the flexible tie thereby fastening the liner to the shell.
Preferably, the flexible tie is inserted through the liner aperture from an inside of the liner.
In accordance with another aspect of the present invention, there is provided a method of fastening a liner to a rotatable shell of a grinding mill, the fastener comprising a flexible tie, a retainer fitting for retaining the fastener relative to an aperture of the liner, and a tensioning fitting, the method including the steps of:
In accordance with yet another aspect of the present invention, there is provided a liner fastener for fastening a liner to a rotatable shell of a grinding mill, the fastener comprising a flexible tie, retaining means for retaining the fastener relative to the liner, and a tensioning fitting, wherein the flexible tie is adapted to be inserted through a mounting aperture in the shell, and the tensioning fitting is adapted to be fitted to an end portion of the flexible tie protruding outside the shell to bear against the shell and to maintain tension. in the fastener to thereby fasten the liner to the shell.
Preferably, the retaining means is in the form of one end portion of the flexible fie being embedded in the liner.
Preferably, the retaining means is in the form of one end portion of the flexible tie being integrally formed as part of the liner.
Preferably, the retaining means is in the form of a retainer fitting attached to one end portion of the flexible tie.
Preferably, the retaining means is in the form of a retainer fitting integrated within the liner, adapted such that the flexible tie may be inserted from an outside of the rotatable shell, through a mounting aperture in the shell, and into the retainer fitting, such that the retainer fitting becomes attached to one end portion of the flexible tie.
More preferably, the retainer fitting is in the form of a wedge collar and barrel assembly.
Preferably, the retaining means is dimensioned so as to prevent lateral movement of the liner relative to the mill shell.
In accordance with yet another aspect of the present invention, there is provided a liner fastener when used to fasten a liner to a rotatable shell of a grinding mill, the fastener comprising a flexible tie, retaining means for retaining the fastener relative to the liner, and a tensioning fitting, wherein the flexible tie is inserted through a mounting aperture in the shell, and the tensioning fitting is fitted to an end portion of the flexible tie protruding outside the shell, the tensioning fitting bearing against the shell to maintain tension in the flexible tie thereby fastening the liner to the shell.
In accordance with yet another aspect of the present invention, there is provided a method of fastening a liner to a rotatable shell of a grinding mill, the fastener comprising a flexible tie, retaining means for retaining the fastener relative to the liner, and a tensioning fitting, the method including the steps of:
The invention is described, by way of non-limiting example only, with reference to the accompanying drawings, in which:
With reference to
Advantageously, the flexible tie 24 enables replacement of the liner 10 without needing to drive the liner fastener 22 back through its original entry path. As the tie 24 is flexible, it is able to bend and move around so as to facilitate removal of the liner 10 from the mill shell 12 without removing the liner fastener 22 from the liner 10. Furthermore, as the tie 24 is flexible, it prevents jamming of the liner fastener 22 in the mounting aperture 32 of the mill shell 12 during removal of the liner 10 from the mill shell 12. Advantageously, the flexible tie 24 may be of relatively smaller cross-sectional dimension than existing liner bolts 14 such that the liner fastener 22 is able to be withdrawn more easily from the mounting apertures 32 in the mill shell 12 during removal of the liner 10 from the mill shell 12.
It is of benefit that the flexible tie 24 may have relatively greater elastic elongation under tension than conventional liner bolts 14. During the grinding process, movement of the liners 10 relative to the shell 12 typically results in tension in conventional liner bolts 14 being reduced, due to their small elastic elongation under tension. This typically leads to mill down time whilst liner bolts 14 are re-tensioned. Advantageously, the arrangement of the present invention may retain tension more effectively, such that re-tensioning of the liner fasteners 22 after a period of mill operation is not required.
Advantageously, the flexible tie 24 may resist fatigue failure caused by vibration and movement of the liner 10 relative to the shell 12 to a greater extent than a conventional liner bolt 14. Fatigue failure of a liner bolt 14 typically leads to mill down time for bolt 14 replacement, while the risk of a dislodged nut 18, washer 16 and shank section of a fractured liner bolt 14 being thrown from the mill during operation and hitting personnel in the area is an ongoing hazard associated with conventional liner bolts 14.
Advantageously, the flexible tie 24, may be used as an anchor point for the liner 10, after the worn liner 10 has been knocked into the mill and requires removal for disposal.
More specifically, with reference to
The flexible tie 24 may be in the form of a length of wire rope which is of relatively smaller cross-sectional dimension than existing liner bolts 14.
The retainer fitting 26 may be dimensioned so as to prevent the retainer fitting 26 From passing through the liner aperture 28. More specifically, the retainer fitting 26 may be generally tapered in a profile which is the negative of a profile of the socket 34 such that the retainer fitting 26 seats within the socket 34 to form a firm anchorage to prevent further outward movement of the liner fastener 22 relative to the liner 10.
The retainer fitting 26 may be dimensioned so as to prevent lateral movement of the liner 10 relative to the shell 12. More specifically, the retainer fitting 26 may generally be dimensioned so as to extend into the mounting aperture 32 in the shell 12 once the retainer fitting 26 is seated in the socket 34 such that any shearing forces between the liner 10 and shell 12 are exerted on the retainer fitting 26 and not the flexible tie 24.
The tensioning fitting 30 may be in the form of a wedge collar 38 and barrel 40 assembly. The wedge collar 38 is arranged within a tapered interior of the barrel 40 to permit one-way movement of the assembly along the flexible tie 24. The inside surface of the wedge collar 38 may be formed with teeth to allow the wedge collar 38 to be slid onto the flexible tie 24 but to prevent withdrawal of the wedge collar 38 from the flexible tie 24 so that tension in the flexible tie 24 is maintained. The wedge collar 38 and barrel 40 assembly may be used in combination with a washer 42, that may comprise a recessed O-ring 44 for sealing between the mill shell 12 and washer 42 to prevent leakage of the mill contents through the mounting aperture 32 of the shell 12. It will be appreciated by those skilled in the art that, in other examples, alternative forms of tensioning fitting 30 may be used.
In use, the flexible tie 24 may be inserted into the liner aperture 28 and a corresponding mounting aperture 32 in the shell 12, and be fed through such that the retainer fitting 26 becomes anchored within the socket 34 formed in the aperture 28 of the liner 10. As shown in
Turning to
Accordingly,
The retainer fitting 26 in the form of the wedge collar 50 and barrel 52 assembly may be integrated within the liner 10. In use the flexible tie 24 may be inserted from an outside of the rotatable shell 12, through the mounting aperture 32 in the shell 12, and into the wedge collar 50 and barrel 52 assembly, such that the wedge collar 50 and barrel 52 assembly becomes attached to an inner end portion of the flexible tie 24. Advantageously, this removes the requirement for an aperture 28 through the liner 10 which would typically lead to accelerated wear rates in that area of the liner 10. This may prolong the useful life of the liner 10. Advantageously, fewer personnel may be required inside the mill during the liner replacement process as the fastener 22 may be fitted from outside the mill.
The tensioning fitting 30 may also comprise a wedge collar 38 and barrel 40 assembly, and a threaded stud 54, nut 56, and washer 58 assembly. The stud 54 is adapted to have an internal bore through which the flexible tie 24 can pass, and is adapted to have a non-round cross-sectional dimension 60 (for example with planar opposed surfaces) along a portion of its length. The washer 58 is adapted to have a corresponding non-round bore within which the stud 54 is arranged, and which is configured to prevent rotation of the stud 54 relative to the washer 58, and an arm 62 extending beyond an outer diameter of the washer 58. In use, torque may be applied to the nut 56, whilst rotation of the stud 54 and washer 58 is prevented via a reactionary force applied to the arm 62, thereby ensuring the applied torque is converted into a linear force, and subsequently tension in the fastener 22.
With reference to
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.
The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
Number | Date | Country | Kind |
---|---|---|---|
2011905443 | Dec 2011 | AU | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/AU2012/001529 | 12/13/2012 | WO | 00 | 6/18/2014 |