Field of invention

The present invention relates to a gyratory crusher composite crushing component and in particular although not exclusively to a composite crushing component that forms one of two halves of a crushing assembly within a gyratory crusher having a support member formed from a second material encapsulated within a cast main body formed from a first material. Background art

Gyratory crushers are used for crushing ore, mineral and rock material to smaller sizes. Typically, the crusher comprises a crushing head mounted upon an elongate main shaft. A first crushing shell is mounted on the crushing head and a second crushing shell is mounted on a frame such that the first and second crushing shells define together a crushing gap through which the material to be crushed is passed. A driving device positioned at a lower region of the main shaft is configured to rotate an eccentric assembly arranged about the shaft to cause the crushing head to perform a gyratory pendulum movement and crush the material introduced in the crushing gap. Example gyratory crushers are described in WO 2004/110626; WO 2010/123431 and WO 2012/005651. Both the head mounted inner and frame mounted outer shells are wear parts and must be replaced following moderate to extensive use. Replacement of the wear parts requires the crusher to be shut-down during the maintenance work. The cumulative effect of temporary breaks in operation is costly as, in most cases, the gyratory crusher is one component of a series of processing steps and the down-time impacts on both pre and post crushing operations. There is therefore a need to maximise the lifetime of the crushing wear parts to reduce the frequency of necessary maintenance work.

GB 1,181,973 describes a reinforced wear part for a gyratory crusher in which a mantle and outer crushing shell is reinforced by an encapsulated retaining assembly. The retaining assembly is formed as a plurality of separate concentric rings to provide circumferential support for the mantle or crushing shell wall at discreet regions.

However, there is a continued need for a crusher wear part that is both convenient to fabricate, optionally via a moulding process, and exhibits enhanced wear resistance.

Summary of the Invention

Accordingly, it is an objective of the present invention to provide a gyratory crusher crushing shell component that exhibits enhanced wear resistance and therefore has a greater operational lifetime. This is achieved by reinforcing the cast shell body by an internally encapsulated support member. The support member is formed from a different material to the main cast body and imparts different physical and mechanical properties to the component to increase its wear resistance. Advantageously, the support member is a substantially rigid structure so as to be self- supporting and capable of being free standing within the cast mould. Preferably, the support member is elongate and extends within the crushing component wall and is entirely encapsulated by the molten cast material. Accordingly, the composite component maybe considered to comprise an internal skeleton or supporting framework formed from a different material to the encapsulating main body. Advantageously, this support structure provides a scaffold on to which a separate reinforcement and/or hardening material may be coated during casting.

According to a first aspect of the present invention there is provided a gyratory crusher composite crushing component comprising: a cast main body formed from a first material and having a crushing face and an opposed rear face, at least one wall defined by and extending between the crushing face and the rear face, the wall having a first end edge and a second end edge ; a support member formed from a second material encapsulated and extending within the at least one wall of the main body; wherein the at least one wall extends around a longitudinal axis of the main body and the support member extends within the at least one wall around the longitudinal axis; characterised in that: the support member extends in an axial direction between the first end edge and the second end edge as a continuous unitary structure.

The support member may extend substantially the full distance in the axial direction between the first and second end edges. Optionally, the support member may extend in the axial direction over only a portion of the length of the wall in the axial direction.

Reference within the specification to 'a unitary structure' are to a structure that is capable of being self-supporting or free-standing. Such a structure includes, for example, an elongate element formed into a coil centred around a longitudinal axis. In this

configuration a lower base region of the coil provides a support for the upper region of the coil. This configuration also includes an elongate element formed into concentric circles that are interconnected or bonded together such that the concentric circles are mechanically connected via a bonding region or linkages positioned between the rings. As will be appreciated, many different shape and configurations of a single unitary structure are possible and are suitable for incorporation within the wall of the present crushing component. Reference within the specification to a 'continuous ^' ' unitary structure encompass a support element that is formed from a single piece of material and is unbroken and does not comprise joints, bonded, or welded regions or interconnecting sections. The term

'continuous ^' ' also encompasses connected structures where each part of the structure is formed from the same material. The same material is defined as being chemically, mechanically and/or physically identical or near identical and for example includes the same physical dimensions such as the thickness.

Reference with this specification to 'encapsulated' refers to the substantially complete enveloping of the support member within the cast wall. In particular, this encapsulation extends over the crushing face and the rear face such that the support member does not protrude and is not exposed at the crushing or rear faces. During the intended 'normal' operation of the present composite component, the crushing face is defined exclusively by the first material of the main body and the skeletal support member is captured entirely internally within the main body wall. However, where the support member is elongate and comprises ends, at least one end may be exposed and/or be visible at a region towards a top or bottom end edge of the main body wall.

Preferably, the support member extends substantially the full axial length of the at least one wall between the first end edge and the second end edge. In particular, the support member extends circumferentially around the longitudinal axis within the wall.

Optionally, the support member is arranged in helical turns around the longitudinal axis to form a coil extending longitudinally in the main axis direction. Preferably, the loops of the coil comprise differing radial diameter. Optionally, the support member is arranged as a plurality of interconnected concentric rings centred around the longitudinal axis and interconnected to form the single unitary structure. Optionally, the rings are bonded together to form a stacked layered structure centred about the longitudinal axis.

Optionally, the rings are welded together. Optionally, the rings are interconnected together via relatively short linkage sections that bond the concentric rings to form a unitary structure, where the linkages are of the same material as the rings and have the same mechanical and physical properties, such as thickness. Accordingly, the conjoined concentric ring assembly is capable of being a free standing structure (e.g., within the mould). This configuration is advantageous both during the moulding process as the support structure is self-supporting and in use to enhance the reinforcement contribution to the wall. Preferably, the support member extends within the wall as a single continuous piece of material that does not comprise interconnections, joints, welded or bonded regions.

Preferably, the support member comprises a configuration of a coil that is wound around the central longitudinal axis that follows helical turns. Alternatively, the single piece support member may comprise a plurality of straight and bent sections so as to extend both circumferentially and axially within the wall between the top and bottom end edges. A single piece support member is advantageous as interconnecting separate pieces by welding can damage the steel by diluting it at the weld points which changes the chemical composition and leads to enhanced wear at the weld joints. Preferably, the support member is positioned within the at least one wall closer to the crushing face relative to the rear face. Alternatively, the support member maybe positioned at an approximate mid-region between the crushing face and the rear face in a radial direction. Preferably, the support member comprises tool steel and the main body comprises manganese steel. Optionally, the composite component may comprise a third material incorporated within the at least one wall around at least a part of the support member. Optionally, the third material comprises a carbide based material, a ceramic or at least one ceramic or carbide pre-cursor.

Optionally, the component may comprise a third material component coated onto the outer surface of the support member prior to encapsulation by the cast material. Optionally, the composite component may comprise a fourth material coated onto the outer surface of the support member wherein the fourth material comprises a bonding agent to increase the bonding strength between the support member and the main body formed from the first material. Preferably, the third and fourth materials are powdered. The crushing component preferably comprises a generally frusto cone shape geometry and wherein the support member is positioned at least in a lower half of the component towards the bottom edge. Preferably, the support member is elongate comprises a first and a second end and is a continuous structure between the first and second ends being devoid of joints, regions of fusion or bonding associated with connecting two or more sections together.

According to a second aspect of the present invention there is provided a gyratory crusher mantle mountable at a crushing head of a gyratory crusher and forming one half of a crushing assembly of the crusher, the mantle comprising a composite component as described herein.

According to a third aspect of the present invention a gyratory crusher shell mountable at a frame of a gyratory crusher in opposed position to a crusher mantle and forming one half of a crushing assembly of the crusher, the shell comprising a composite component as described herein.

According to a fourth aspect of the present invention there is provided a method of reinforcing a gyratory crusher crushing component, the method comprising: casting a first material to form a cast main body having a crushing face and an opposed rear face, at least one wall defined by and extending between the crushing face and the rear face, the at least one wall extending around a longitudinal axis of the main body; characterised by:

encapsulating within the cast main body a support member formed from a second material, the support member extending within the at least one wall around the longitudinal axis and in an axial direction between a first end edge and a second end edge as a continuous unitary structure.

Optionally, the method further comprises adding a third material onto an outer surface of the support member prior to encapsulating the support member with the first material to form the composite cast body. According to a fifth aspect of the present invention there is provided a gyratory crusher comprising at least one composite crushing component as described herein.

According to a sixth aspect of the present invention there is provided a gyratory crusher comprising a first composite crushing component in the form of an inner shell (mantle) as described herein and an opposed second composite crushing component in the form of an outer shell (concave) as described herein.

Brief description of drawings

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

Figure 1 is a cross sectional side view of a gyratory crusher having a crushing mantle mounted upon a head and an opposed crushing shell mounted at a frame to define a crushing zone according to a specific implementation of the present invention;

Figure 2 is an internal perspective view of the crushing mantle of figure 1 formed as a composite component having an internal support within the walls of the mantle body according to a specific implementation of the present invention;

Figure 3 is a graph of the combined thickness of the two crushing shells against working hours within a crusher for various different types of crushing shells including the internally reinforced crushing shells of figures 1 and 2.

Detailed description of preferred embodiment of the invention

Referring to Figure 1, the gyratory crusher comprises a frame 113 having an upper frame part 101 and a lower frame part 107. A crushing head 103 is mounted upon an elongate main shaft 104. A first crushing shell (typically referred to as a mantle) 102 is fixably mounted on crushing head 103 and a second crushing shell (typically referred to as a concave) 100 is fixably mounted at top frame part 101. A crushing zone 108 is formed between the opposed crushing shells 102, 100. A discharge zone 109 is positioned immediately below crushing zone 108 and is defined, in part, by lower frame part 107.

Relative to a longitudinal axis 114 extending through the crusher and the crushing head 103 and the main shaft 104, a diameter of a cross section of crushing zone 108 increases in the axial downward direction from an upper input end 115 to a lower discharge end 116. Accordingly, a spatial gap between the opposed crushing shells 10, 102 decreases in the axial downward direction from input end 115 to discharge end 116. As will be

appreciated, the upper frame part 101 and lower frame part 107 surround the crushing head 103 and main shaft 104.

A drive motor (not shown) is coupled to main shaft 104 via suitable gear mechanisms and drive shafts (not shown) positioned between the drive motor and main shaft 104.

Accordingly, crushing head 103 and main shaft 104 are configured to rotate according to an eccentric rotational motion about the longitudinal axis 114. The spatial gap between the opposed crushing shells 102, 100 is thereby increased and decreased to crush the material introduced at input end 115, with crushed material being discharged into discharge zone 109 via discharge end 116. The eccentric rotational motion of crushing head 103 is supported by a composite bearing assembly having bearing 106 positionally retained by a bearing support 105 and in particular the mating contact between a bearing surface 111 of crushing head 103 and an opposed bearing surface 110 of bearing 106. Mantle 102 and concave 100 are formed as composite crushing shells. In particular, mantle 102 comprises a cast main body 125 formed from a first material and encapsulating an elongate substantially rigid support member 126 formed from a second material. Main body 125 defines a crushing face 123 orientated to be facing away from axis 114 and a mounting face 124 orientated towards axis 114 and positioned in mating contact with crushing head 103. Mantle 102 is generally frusto cone shaped and extends between a lower and larger diameter annular bottom end edge 127 and a relatively smaller diameter annular upper end edge 128. Similarly, the second crushing shell (concave) 100, that surrounds the radially inner shell 102 comprises a generally frusto cone shape. Concave 100 comprises a cast main body 119 formed from a first material and encapsulating a corresponding elongate substantially rigid support member 122 formed from a second material. Main body 119 defines a crushing face 117 positioned in opposed relationship to the crushing face 123 of mantle 102 and a mounting face 118 in mating contact with frame 101. Main body 119 defines the annular wall of outer shell 100 and extends between a larger diameter lower annular end edge 120 and a relatively smaller diameter upper annular end edge 121. As illustrated in figures 1 and 2, the support members 122 and 126 of the respective mantle 102 and concave 100 are elongate structures that are encapsulated within the crushing shell walls during casting of the wear part components 100, 102. In particular, each support member 122, 126 maybe regarded as continuous within the wall of the respective wear parts 100, 102 and extends along a helical turned path around longitudinal axis 114 between the respective bottom end edges 120, 127 and the respective upper end edges 121, 128. Each support member 122, 126 comprises a uniform cross section (thickness) that is generally circular in profile. Additionally, each support member 122, 126 is a self- supporting structure and is capable of being free standing. This is advantageous in that each component 122, 126 is positionable within the cast mould (for example a cope and drag) to provide a scaffold for the support of additional (powdered) materials that maybe introduced into the mould prior to introduction of the first cast material (to form the respective main bodies 119, 125). According to the specific implementation, each main body 119, 125 comprises a manganese steel (mangalloy) and the respective internally encapsulated support members 122, 126 comprise tool steel. According to further specific implementations, a carbide material or other hardening additive is coated around at least a portion of an outer surface of one or both support members 122, 126 prior to introduction of the molten cast material 119, 125 into the mould cavity.

According to a specific implementation, each support member 122, 126 is radially positioned within each respective main body wall 119, 125 closer to the respective crushing face 117, 123 than the opposed mounting face 118, 124. Positioning the support members close to the respective crushing faces has been found to further increase the wear resistance of the wear parts 100, 102. It has also been observed that incorporating the support members 122, 126 within the wear parts 100, 102, positively enhances the bending characteristics of the shells 100, 102. This physical property facilitates the crushing action of material within crushing zone 108 and provides a more energy efficient crushing action due to the bending and shearing effects imparted by the wear parts 100, 102.

Figure 3 illustrates the improved longevity of the crushing shells 100, 102 of the present reinforced composite materials relative to non-composite crushing shells of differing cast materials. The combined wall thickness between the crushing face and opposed support face of the concave and mantle 102 of the subject invention against the working hours within a crusher is represented by results 300 where the mantle 102 (and not the concave 100) is reinforced with the internally encapsulated support member 126. Results 301, 302, 303 relate to conventional crushing shells without an internally encapsulated support 122, 126. Result 301 were generated using high quality manganese steel whilst the shell components 100, 102 of results 302, 303 comprise lower grade 'mining standard' manganese alloys. As can be seen, after 150 hours working operation within the crusher the reinforced composite components of the present invention comprise a combined wall thickness that is approximately 40% greater than the high quality manganese components (301); and approximately 50% and 70% greater than the respective lower grade manganese steel components of results 302, 303.

As the mantle 102 is a smaller diameter component than concave 100, the mantle wear rate is generally greater than that of the concave. Accordingly, where both the mantle 102 and the concave 100 comprise respective support members 126, 122, a diameter of the elongate support 126 within the mantle 102 is greater than that of the support member 122 within the concave 100. This configuration establishes that the wear rate of each shell 100, 102 is approximately 1: 1 for any given time of normal crushing operation.

According to further specific implementations, the respective support members 122, 126 may comprise any geometry and maybe formed from a layered stack of complete or partial concentric annular rings that decrease in diameter from bottom to top between the respective lower 120, 127 and upper edges 121, 128 of each shell 100, 102. The rings maybe bonded together using conventional bonding techniques such as welding prior to encapsulation by the first material of the main body 119, 125. According to yet further specific implementations the support members 122, 126 maybe retained in position within the cast mould by a structural support component prior to introduction of the cast material.