WEAR RESISTANT MATERIAL
INTRODUCTION TO THE INVENTION
This invention relates to a wear or abrasion resistant material and to articles made therefrom.
BACKGROUND TO THE INVENTION
Specific mention is made in this specification to articles used in the mineral beneficiation industry. This should not be construed as limiting the scope or nature of the invention in any way.
In the manufacture of articles for the mining and mineral beneficiation industries such as screens, and stators and rotors for flotation equipment, for example, one of the most important considerations is that of durability. These parts must not only have a high resistance to wear or abrasion but must often have a high
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impact resistance as well. This requirement has at least partly been achieved by the use of polyurethane and similar materials.
An object of this invention is to provide a material of improved durability and which is suitable for use in manufacturing wear parts and the like for mining, minerals beneficiation and other equipment.
DEFINITION
in this specification the term "settable material" means materials that set from a liquid form and have elastically deformable qualities (eg. polyurethane) and the term "glass" includes ceramics and excludes glass in a fibre form.
SUMMARY OF THE INVENTION
According to the invention a wear resistant material comprises a settable material and is characterised in that the settable material is mixed with finely divided particles of glass, the particles being non elongate in configuration.
Further according to the invention the settable material is a polyurethane or similar material.
Still further according to the invention the finely divided particles are bead like or ball like in configuration.
Still further according to the invention the particles have a maximum diameter of between 0,5 and 4mm and preferably between 2 and 3mm.
Still further according to the invention the majority of the particles may be substantially of the same size or alternatively there may be particles of different sizes.
Still further according to the invention the particles are ceramic particles and the ceramic particles are aluminite particles.
Still further according to the invention, there is a layer of adhesive on the particles, the adhesive being adapted to secure the particles to the settable material.
According to a further aspect of the invention a method of making a wear resistant material comprises coating finely divided particles of glass with a suitable adhesive, mixing the coated glass particles with a suitable settable material, and allowing the settable material to set.
According to a further aspect of the invention a method of making a wear resistant article comprises making at least a part of the article with the wear resistant material as defined above.
Further according to this aspect of the invention the part of the article is cast in the wear resistant material.
Still further according to the invention the part of the article is cast from wear resistant material and includes anchor formations projecting therefrom and the part is then cast with a remaining portion of the article so that the anchor formations are embedded in said remaining portion.
According to a further aspect of the invention there is provided articles made from the wear resistant material as defined.
Further according to this aspect of the invention this article may be a screen element, a rotor or stator for flotation machines, liners for machines, pipes and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention described by way of example only follows with reference to the accompanying drawings in which:
Figure 1 is a diagrammatic sketch of a rotor of a flotation machine according to a first embodiment of the invention; and
Figure 2 is a diagrammatic sketch of magnified sectioned portion of the material from which the rotor is made; and
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Figure 3 is a diagrammatic sketch of a screen element according to the second embodiment of the invention; and
Figure 4 is a diagrammatic sectional elevation of part of an article made in accordance with another aspect of the invention.
DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS
In the first embodiment of the invention (shown in Figure 1) a rotor (1) for an item of flotation equipment (not shown) is provided.
The rotor (1) comprises seven blades (2) extending radially from a central hub (3), the blades each being of a substantially rectangular configuration.
The rotor (1) is cast in a suitable mould from a material comprising a settable polyurethane (4) which is substantially saturated with balls or beads (5) of aluminite, a ceramic material. The ceramic beads have a maximum diameter in the region of about 2mm and the section through the material (shown in Figure 2) shows the beads dispersed in the material (4) with the section being taken through various portions of the beads so distributed. The beads are not all of the same size so that the saturation of the polyurethane is improved. It will be appreciated that this size distribution will determine the ultimate characteristics of the article. It follows that if the beads are all of the same size there will be larger voids between beads and these voids will hold polyurethane giving a product which is more flexible than one in which the voids are partially filled with smaller beads.
In preparing the casting material the beads (5) are first cleaned in a suitable solvent such as carbon tetrachloride and they are then coated with a suitable adhesion producing material such as an adhesive to ensure that they adhere to the polyurethane material when it sets. A suitable adhesive is that sold under the name Ecorrlok VS13 by Chemlok of the United States of America. The coating of the adhesive is done by immersing the beads in the adhesive, allowing the adhesive to drain off and then ensuring that the beads are kept in motion relative to one another so that they do not stick together before the adhesive is dry and/or they are introduced into the liquid polyurethane material.
In Figure 3 a second embodiment of the invention is provided. This embodiment provides for a square polyurethane screen panel (10) having a plurality of inverted truncated pyramidal apertures (11) there through as is well known in the art.
The panel (10) is made from a wear resistant material as defined above and which is further characterised in that the ceramic beads therein (not shown) are of a reasonably wide range of sizes to ensure a satisfactory saturation of the polyurethane and hence enhance the abrasion resistance of the screen while maintaining some flexibility.
In the embodiment shown in Figure 4 a part (20) of an article is depicted.
This part (20) comprises a panel (21) of abrasion resistant material located in a generally rectangular parallelepipedal body (22) of polyurethane material.
The panel (21) is made in the manner disclosed above and additionally includes a plurality of undercut formations (23) projecting from the sides (24) thereof which are embedded in the body (22). These anchoring formations may be integral with the panel (21 ) or may be formations which are cast into the panel during the manufacture thereof.
It will be readily appreciated that the anchors secure the panel to the body (22) when the panel is cast into that body.
Initial tests indicate that rotors and other equipment made from material described above have improved durability in particular wear resistance without loss to any significant extent of the flexibility of the material.
Other embodiments are envisaged within the scope of the invention including other applications and in particular applications to wear parts in the mining, mineral processing and other industries.