ZA200905085B - Holder for inserts - Google Patents

Description

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FIELD OF THE INVENTION

This invention relates to a holder for a tungsten carbide insert for a centrifugal mineral breakers.

BACKGROUND OF THE INVENTION

Centrifugal mineral breakers comprise spaced apart horizontal plates that retain peripheral holders which are provided with wear-resistant inserts. The configuration of the mineral breakers include walls that are located to retain rock particles as a lining so that the walls are protected from continuous abrasion caused by the accelerated mineral particles. The holders include short angled surfaces that serve as retainers the rock material for the same purpose so that the mineral being accelerated first strikes the lining before exiting the breaker over the edge of the holders fitted with the inserts.

The inserts are subject to great abrasion and wear quite rapidly, the greater the wear the greater the necessity to replace these expensive inserts.

The degree of wear caused to the zones of the holders adjacent the inserts is also of importance because a particular zone or zones may be worn away to expose the insert and even to cause its ejection from the channel retaining it, or necessitate the discarding of the holder that still has a significant amount of the tungsten carbide insert.

Another problem that has been encountered is the uneven wear of the top surface of the insert, the wear being greater in the central portion with the result that the insert is useless when the central zone has been eroded while the outer zones are increasingly non-eroded at the top and bottom ends thereof. This results in wastage of expensive tungsten carbide.

It is an object of the present invention to provide significant improvements that result in greater protection of the holders and a simplified construction of the mineral breaker.

The invention also aims to provide for a uniform wear pattern of the inserts to reduce wastage. 2 1 N .

THE INVENTION

According to the invention a mineral breaker includes a pair of spaced apart plates with peripheral recesses for receiving holders each of which presents a surface at an angle to the radius that passes through the centre point of its recess at the periphery

In one form of the invention the recesses may be substantially rectangular, triangular, square, trapezoidal or other geometric shape to receive correspondingly shaped holders, the axes of the recesses being at angles to the radius of the plates at the recesses.

The recesses may also be circular, partly circular, ovaloid or other curved form. These may require suitable retaining means or configurations to prevent rotation of the holders.

In another form of the invention the holders include a first zone that is adapted to be accommodated in a radial recess and a second zone that is at angle to the first zone for it to be at a predetermined angle to the radius. Such an arrangement is described in my co-pending RSA Patent Application :

In comparison to the prior art the insert will be located at a greater distance from the centre of the mineral breaker. This has the advantage that the insert will travel at a comparatively greater rotational speed than that of prior art mineral breakers for a given rotor radius, thereby resulting in a concomitant higher mineral breaking rate and/or savings in power for the same output.

By virtue of the angle there is an increased area of holder surface that is presented to the rock particles

In a preferred form of the invention the insert-retaining siot of the holder has a central vertical zone of greater horizontal dimension that that of the remainder of the holder and is adapted to provide a wear pattern in the central vertical zone that is greater than that of the top and bottom zones so that the central zone wears to substantially the same thickness as the top and bottom zones. Such an arrangement is described in my co- pending RSA Patent Application No.

The retaining slot for the insert may be stepped from the top and bottom towards the central zone for receiving regular inserts to provide the pattern desired.

The holder of the invention may include multiple rows of inserts and/or back-up inserts.

In a refinement of the invention the angled surface of the holder is corrugated or otherwise formed for increased stiffness and surface area in order to collect more mineral matter for additional protection of the holder and insert. The corrugated formations also serve to retain mineral particles.

EMBODIMENT OF THE INVENTION

An embodiment of the invention is described below with reference to the accompanying drawings, in which:

Figure 1 is a plan view of a rotor for a mineral breaker illustrating three of the many arrangements for the holder;

Figure 2 is a similar view showing a particular form of the invention;

Figure 3 is a similar view showing a modification of the arrangement of Figure 2;

Figure 4 is a similar view showing another form of the invention;

Figure § is a similar view showing a modification of the arrangement in Figure 4;

Figure 6 is a similar view of yet further form of the invention;

Figure 7 is a diagrammatic representation of alternative shapes of recesses and opening; and

Figure 8 is a diagrammatic representation of sectional views through various slot shapes for inserts.

Referring first to Figure 1, three of the many possible arrangements is shown without the holders in position for illustrative purposes. Three different recesses or slots are shown

’ and are indicated as (2, 3) because of the reference to Figures 2 and 3, and as (4, 5) because of the reference to Figures 4 and 5, and the slot 6 (reference Figure 6). in Figure 1 the radii 10 are indicated in broken line to show that the recess 4, 5 has its axis 12 at an angle to the radius. The same applies to the opening 6. The recess 2, 3 is on the radius but the contact surface of the holder is at an angle to the radius as will be described below.

Figure 2 has a rectangular recess 20 with a holder 22 having a shape in plan substantially as shown that presents an angled surface 24 for rock particles as indicated above. An insert 26 is located in a slot 28. In Figure 3 the slot 30 is stepped as described above and provides a central zone 32 that ensures even longitudinal wear of the insert.

Turning to Figures 4 and 5, the holders 40 are trapezoidal in plan to be retained in the corresponding recesses 42. Inserts 44 are located in corresponding slots 46. In Figure 5, as in Figure 3, the slot 46 stepped and is includes a central zone 48 that ensures even longitudinal wear of the insert.

In Figure 6 a recess is replaced by an opening 60 that receives a holder 62 with insert 64.

In Figure 7 a part-circular recess 70, an ovaloid recess 72 and a circular opening 74 are shown to provide an indication of a number of alternative shapes of recesses and openings.

In Figure 8 three different cross sectional forms of slots for inserts are depicted. In each case the outside surface is indicated by reference 80 and individual tungsten carbide pieces are indicated by reference 82.

Claims (10)

1. : / « CL CLAIMS: A mineral breaker including a pair of spaced apart plates with peripheral recesses for receiving holders each of which presents a surface at an angle to the radius that passes through the centre point of its recess at the periphery .
2. 2. A mineral breaker according to claim 1 in which the recesses are substantially rectangular, triangular, square, trapezoidal or other geometric shape to receive correspondingly shaped holders.
3. 3. A mineral breaker according to claim 1 in which the recesses are circular, partly circular, ovaloid or other curved form.
4. 4, A mineral according to claim 1 in which the holders include a first zone that is adapted to be accommodated in a radial recess and a second zone that is at angle to the first zone for it to be at an angle to the radius.
5. 5. So A mineral breaker according to any of the above claims in which the insert-retaining slot of the holder has a central vertical zone of greater horizontal dimension that that of the remainder of the holder and is adapted to provide a wear pattern in the central vertical zone that is greater than that of the top and bottom zones so that the central zone wears to substantially the same thickness as the top and bottom zones.
6. / / A mineral breaker according to claim 5 in which the retaining slot for the insert is stepped from the top and bottom towards the central zone for receiving regular inserts to provide the pattern desired.
7. 7. A mineral breaker according to any of the above claims in which the holder includes multiple rows of inserts and/or back-up inserts.
8. 8 A mineral breaker according to any of the above claims the angled incident surface of the holder is corrugated or otherwise formed for increased stiffness and surface area in order to collect more mineral matter for additional protection of the holder and insert and to retain rock particles. ve
9. 9. A mineral breaker substantially as described with reference to any of the accompanying drawings.
10. 10. A holder for a mineral breaker according to any of the above claims substantially as described with reference to the any of the accompanying drawings. Dated this 15 day ( 2009 i MORRISON FORSTER INC. APPLICANTS PATENT ATTORNEYS