"A BASKET"

FIELD OF THE INVENTION

This invention relates to a basket. In particular the invention relates to a basket for use in a mineral processing centrifuge that has improved wear properties.

BACKGROUND OF THE INVENTION

Centrifuges have been used in mineral processing industry for some time. Centrifuges are primarily used to dewater minerals and ores. A component of most centrifuges is a basket which is rotated in order to dry the minerals. In use, mineral slurry is fed into a feed end of the basket whilst the basket is rapidly spinning to cause the slurry to be forced against an inner periphery of the basket. The centrifugal force imparted to the mineral slurry causes water to be forced from the ore through slots located within the basket.

A major issue with the use of the centrifuges is the amount of basket wear.

Most basket wear is caused adjacent the feed end of the basket, where the slurry is fed. Wear to the basket generally occurs when the slurry that is being processed moves tangentially (i.e. the material rotates) around the basket. When a basket wears prematurely, the basket must be replaced. This is costly due to cost of the basket and the substantial downtime cost.

US Patent number 6,109,452 discloses a basket for use in a centrifuge that has improved wear properties. The basket is formed from a plurality of spaced-apart circumferential ribs and axial stringers that joined together to form a series of apertures. Bridging each aperture at one end of the basket is a series bars made from a wear resistant material, such as tungsten carbide, silicon carbide or ceramic. The bars are configured so that, when arranged side-by-side and end-to-end, they form apertures between adjacent bars.

The wear that is caused on the bars is less than the steel that is traditionally used. Unfortunately, tangential movement of the slurry still causes wear on the metal circumferential ribs causing premature failure of the basket. Further the labor costs of manufacturing the basket are high as each individual bar is required to be individually attached to the metal frame. This makes the manufacture of the basket cost prohibitive.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

OBJECT OF THE INVENTION

It is an object of the invention to overcome and/or eliminate one or more of the above disadvantages or to provide the consumer with a useful or commercial choice.

SUMMARY OF THE INVENTION

In one form, although not necessarily the only or broadest form, the invention resides in a basket for use in a centrifuge, the basket having an first portion which is more resistant to tangential wear then a second portion.

In another form the invention resides in a basket for a centrifuge, the basket comprising:

a frusto-conical body having a first portion and a second portion;

the first portion further comprising at least one wear member.

The wear member may located on the interior of the first portion of the body.

The wear member may be made from an integrally formed wear material.

Preferably the first portion and the second portion are detachably connected to each other.

The body includes a feed end and a delivery end. The feed end is located adjacent a small diameter end of the body whilst the delivery end is located adjacent a large diameter end of the body.

The first portion of the body is located adjacent the feed end of the body.

The wear member may be formed by applying a wear material to a backing plate.

The wear member may be formed from a mouldable or castable wear material.

The wear material is preferably Siliconized Silicon Carbide. However other suitable wear materials may be used such as alumina ceramic or Ni-hard.

Normally there is only a single wear member. The wear member may also be substantially frusto-conical in shape. The wear member may be a solid annular ring with no slots. Alternatively, the wear member includes slots.

The wear member may include one or more vanes on an inner face of the wear member. The vanes may be integrally formed with the wear member. Alternatively, the vanes may be otherwise attached to the wear member. The vanes may extend axially along the wear member. The vanes may extend approximately one half to two-thirds the length of the wear member. The vanes may extend from adjacent a feed end of the wear member.

A circumferential wall may be located adjacent to the inner face of the wear member. The circumferential wall may be located adjacent a delivery end edge of the wear member. The circumferential wall may be located adjacent an end of the vanes. The circumferential wall may be integrally formed with the wear member or the vanes. Alternatively, the circumferential wall may be otherwise attached to the wear member or vanes.

The second portion of the body may be located adjacent the delivery end of the body. Preferably, the second portion of the body is made from less wear resistant materials than the wear member. The second portion normally includes steel or stainless steel wedge or profiled wires. Normally, the adjacent surfaces of the first and second portions are smoothly joined together so as to form a single continuous basket. The wear member may be tapered adjacent a joint between the first portion and the second portion.

The first portion of the body may be detachably connected to the second portion. A first attachment member forms part of the first portion to attach the first portion to the second portion. A second attachment member forms part of the second portion to attach the second portion to the first portion. The attachment members of the first and second portions may be in the form of a flange.

Preferably, the first portion extends approximately one-third of the length of the basket and the second portion comprises the remaining two-thirds.

In another form, the invention resides in a basket for a centrifuge, the basket comprising:

a frusto-conical body having a first portion and a second portion, the first portion further comprisomg at least one wear member wherein the wear member includes at least one arcuate segment.

The arcuate segment may be integrally made from wear material.

The body includes a feed end and a delivery end. The feed end is located adjacent a small diameter end of the body whilst the delivery end is located adjacent a large diameter end of the body.

The first portion of the body is located adjacent the feed end of the body.

The wear material may be formed from a mouldable or castable material. The wear material is preferably Siliconized Silicon Carbide. However other suitable wear materials may be used such as alumina ceramic or Ni-hard.

Preferably, there is a plurality of arcuate segments. The arcuate segments can form of an annular ring.

Each arcuate segment may be solid with no slots. Alternatively, each arcuate segment may include slots.

Each arcuate segment typically includes at least one vane, but may have a plurality of vanes. The vanes may extend axially along the arcuate segment. The vanes may extend approximately one-half to two-thirds the length of the arcuate segment. The vanes may extend from adjacent a feed end of the arcuate segment.

A circumferential wall section may be located adjacent to an inner face of each arcuate segment. The circumferential wall section may be located adjacent a delivery end edge of each arcuate segment. The circumferential wall section may be located adjacent an end of the vanes. The circumferential wall section may be integrally formed with the arcuate segment or the vanes. Alternatively, the circumferential wall section may be attached to the arcuate segment or the vanes.

The second portion of the body is located adjacent the delivery end of the basket. Preferably, the second portion of the body is made from less wear resistant materials than the arcuate segment. The second portion normally includes steel or stainless steel wedge or profiled wires. Normally, adjacent surfaces of the first portion and second portion are smoothly joined together so as to form a single continuous inner surface of the basket. The arcuate segments may be tapered adjacent a joint between the first portion and the second portion.

The first portion of the body may be detachably connected to the second portion. A first attachment member forms part of the first portion of the basket to attach the first portion to the second portion. A second attachment member forms part of the second portion of the body to attach the second portion to the first portion. The attachment members of the first and second portions may be in the form of a flange.

Preferably, the first portion preferably extends approximately one-third of the length of the basket and the second portion comprises the remaining two- thirds.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiment of the invention, by way of example only, will now be described with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a basket according to a first embodiment of the invention;

FIG. 2 is a perspective view of a basket according to a second embodiment of the invention; and

FIG. 3 is a perspective view of a basket according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a basket 10 that is used within a horizontal centrifuge. In particular, the basket shown can be used in the HFC 1300 centrifuge is current manufactured by FLSmidth Ludowici Pty Ltd. However it should be appreciated that the basket may be routinely modified to fit within other centrifuges.

The basket 10 is formed from a body 20 in the shape of a truncated cone. Accordingly, the body includes a feed end 21 (located adjacent a small diameter of the body) and a delivery end 22 (located adjacent a large diameter of the body). The body is split into a first portion 30 which includes the feed end and a second portion 40 that includes the delivery end.

The first portion includes a wear member 31 , a back member 32, a first attachment member 33 and a feed end flange 34. The wear member 31 is located between the first attachment member 33 and the feed end flange 34. The wear member 31 is cast from Siliconized Silicon Carbide (known as "SiSiC"). The wear member 31 is a solid annular ring with a series of vanes 36 (know in the art as "accelerator bars") which are integrally formed. The wear member 31 is in the shape of a truncated cone. The vanes 36 extend axially along the wear member 31 . A delivery end edge 37 of the wear member 31 , located adjacent the first attachment member, is tapered.

The wear member 31 is fastened to the backing member 32, first attachment member 33, and the feed end flange 34 using an adhesive such as epoxy or other fastening means. It would be appreciated by a person skilled in the art which adhesives or other fastening means are suitable depending on the use of the basket 10, the material the wear member 31 is made from and the material that the first attachment member 33 and/or feed end flange 34 and/or backing member 32 is made from.

The backing member 32 is located behind the wear member 31 . The backing member 32 is made from steel. The backing member 32 is connected to and located between the first attachment member 33 and the feed end flange 34. The first attachment member 33 is made from steel. The first attachment member 33 extends outwardly with respect to the wear member 31 and is fastened to the wear member 31 . A series of holes 48 extend through the first attachment member 33. The holes 48 are circumferentially spaced around the first attachment member 33.

The feed end flange 34 is also made from steel. The feed end flange 34 extends inwardly with respect to the wear member 31 and is fastened to the wear member 31 .

The second portion 40 is formed from a screen member 41 , second attachment member 42 and delivery end flange 43. The screen member 41 is located between the second attachment member 42 and the delivery end flange 43. The screen member 41 is from a series of spaced-apart circumferential ribs 44 and series of axial stringers 45. The stringers 45 are welded to the ribs 44. The stringers 45 are placed radially outward from ribs 44. Secondary screen elements 46 are attached to the ribs 44. The secondary screen elements 46 are normally in the form of a plurality of wire members that are arranged side-by-side. The wire members are spaced slightly apart so as to form slots 47. Normally, the slots 47 are formed by the arranging the wire members so that the wire members extend axially relative to the basket. Wire members are normally formed from steel or stainless steel wedge or profiled wires.

The second attachment member 42 is made from steel. The second attachment member 42 extends outwardly with respect to the screen member 41 and is connected to screen member 41 . A series of holes 48 extend through the second attachment member 42. The holes 48 are circumferentially spaced around the flange. In use, the first attachment member 33 and the second attachment member 42 are located adjacent to each other so that bolts (not shown) can extend through respective holes 48 in each flange to attach the first portion 30 and the second portion 40 together.

The delivery end flange 43 is made from steel. The delivery end flange 43 extends outwardly with respect to the screen member 41 and is connected to screen member 41 . A series of holes 49 extend through the delivery end flange 43 to connect the basket 10 to a basket carrier (not shown) via bolts (not shown). The holes 49 are circumferentially spaced around the flange.

In use, the basket 10 is used within a horizontal centrifuge in a normal manner. In normal use, the first portion 30 will outlast the second portion 40. According, often only the second portion 40 is required to be changed after a period of use. In this instance, the first portion 30 is removed from the second portion 40 by removing the bolts through the first attachment member 33 and the second attachment member 42. A new second portion 40 is then attached to the old first portion 30 by placing bolts through the old first attachment member 33 and the new second attachment member 42. It is envisaged that the first portion 30 will last at least three times longer than the second portion 40. In the instance when both the first portion and the second portion are worn, the entire basket 10 is replaced in a normal manner.

FIG 2 shows a second embodiment of the basket 10. Again, like numerals have been used to describe like components. In this embodiment, a circumferential wall 50 is located adjacent to an inner face 35 of the wear member 31 . The circumferential wall 50 is located adjacent a delivery end of the wear member 31 . The circumferential wall 50 is made of SiSiC and is integrally formed with the wear member 31 and vanes 36. FIG 3 shows a third embodiment of the invention. Again, like numerals have been used to describe like components. In this embodiment, the wear member 31 is formed by a plurality of arcuate segments 60 made from cast SiSiC. Each arcuate segment 60 includes an inner face 61 , a plurality of vanes 36 and a circumferential wall section 62, which are all integrally formed. In order to produce the first portion 30, the arcuate segments 60 are fastened to the backing member 32, first attachment member 33 and feed end flange 34 once the feed end flange 34 and first attachment member 33 are connected to the backing member 32. Once all the arcuate segments 60 are installed, they form an annular ring and the circumferential wall sections 62 form a circumferential wall 50.

In this specification, the terms "comprise", "comprises", "comprising" or similar terms are intended to mean a non-exclusive inclusion, such that a system, method or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.

It should be appreciated that various other changes and modifications may be mode to the embodiments described without departing from the spirit and/or scope of the invention.