Wear resistant VSI crusher distributor plate

Abstract

A distributor plate assembly for a vertical shaft impact (VSI) crusher is optimized for abrasion wear resistance. The distributor plate includes a plurality of plate segments, each segment being formed from a main body of ductile iron alloy having cemented carbide granules embedded within the iron alloy.

Claims

1. A distributor plate assembly releasably mountable to protect a disc of a rotor within a vertical shaft impact crusher from material fed into the rotor, the assembly comprising: a plurality of segments, each segment including a main body having a contact surface positioned in an upward facing direction arranged to contact material fed into a rotor, the main body being ductile iron alloy incorporating nodular graphite and cemented carbide granules embedded within the iron alloy, wherein the main body includes outer edges that form a perimeter region, the main body being modular, wherein the plurality of segments is arranged in a circumferential direction around a central axis; and a first insert mounted in the main body of at least one of the plurality of segments such that an upper surface of the first insert forms a part of and is coplanar with the contact surface of the main body, the first insert including at least two radially outward facing edges, the at least two radially outward facing edges of the first insert forming a part of and extending only to the perimeter region of the main body, wherein each of the at least two radially outward facing edges of the first insert is co-aligned with a respective outer edge of the perimeter region of the main body, and wherein the at least two radially outward facing edges of the first insert do not extend past the outer edges of the perimeter of the main body, the first insert being abrasion wear resistant relative to the main body.

2. The assembly as claimed in claim 1, wherein the first insert is a plate, the main body being formed around the plate.

3. The assembly as claimed in claim 2, wherein the first insert has a polygonal shape profile.

4. The assembly as claimed in claim 1, wherein the first insert is a cemented carbide material.

5. The assembly as claimed in claim 1, further comprising a second abrasion wear resistant insert positioned at a rearward surface of the main body, the rearward surface being opposite the contact surface and configured to mount the assembly at the disc of the rotor.

6. The assembly as claimed in claim 5, wherein the second insert is a plate positioned at the perimeter region of the main body to form a region of the rearward surface, at least a part of the second insert being positioned immediately behind the first insert.

7. The assembly as claimed in claim 6, wherein the main body includes a recess at the region of the rearward surface, the second insert being accommodated within the recess at the rearward surface.

8. The assembly as claimed in claim 1, wherein the carbide granules are any one or a combination of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, cobalt, and nickel.

9. The assembly as claimed in claim 1, wherein the carbide granules embedded in the main body penetrate from the contact surface towards an opposite rearward surface through the main body to a depth up to 50% of a total thickness of the main body between the contact and rearward surfaces.

10. The assembly as claimed in claim 5, wherein each segment includes the first insert and the second insert positioned at the respective contact and rearward surfaces.

11. A vertical shaft impact crusher rotor comprising a distributor plate assembly according to claim 1.

12. A vertical shaft impact crusher comprising a rotor as claimed in claim 11.

13. The assembly as claimed in claim 2, wherein the upper surface of the first insert is positioned co-planar with the contact surface of the main body.

14. The assembly as claimed in claim 1, wherein the first insert is a low friction material relative to the main body.

15. The assembly as claimed in claim 1, wherein a surface area of the upper surface of the first insert relative to a surface area of the contact surface of the main body is in the range of 10 to 50%.

16. The assembly as claimed in claim 1, wherein one end of each of the at least two radially outward facing edges of the main body are joined to form a vertex, the first segment being located at the vertex.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

(2) FIG. 1 is an external perspective view of a VSI crusher rotor having an upper and lower disc separated by a plurality of wall sections;

(3) FIG. 2 is a perspective plan view of the rotor of FIG. 1 with the upper disc removed for illustrative purposes;

(4) FIG. 3 is a plan view of the rotor of FIG. 2;

(5) FIG. 4 is an upper perspective view of a segment of a distributor plate according to a specific implementation of the present invention;

(6) FIG. 5 is a further view of the distributor plate segment of FIG. 4 rotated about a central axis;

(7) FIG. 6 is a further view of the distributor plate segment of FIG. 4 rotated about the central axis;

(8) FIG. 7 is an underside perspective view of the distributor plate segment of FIG. 4 according to a specific implementation of the present invention;

(9) FIG. 8 is a partial exploded perspective view of the underside of the distributor plate segment of FIG. 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

(10) Referring to FIG. 1, a rotor 100 of a vertical shaft impact (VSI) crusher comprises a roof in the form of an upper horizontal disc 101 having an upper wear plate 103, and a floor in the form of a lower horizontal disc 102 separated by a vertical rotor wall 106. The lower disc 102 comprises a hub 105, which is welded centrally to a lower surface of disc 102 and is configured to be connected to a vertical shaft (not shown) for rotating rotor 100 within a main housing (not shown) of the VSI-crusher. Upper disc 101 has a central aperture 104 through which material to be crushed may be fed into rotor 100. Upper horizontal disc 101 is protected from crushable material impacting the rotor 100 from above by a top wear plate 103.

(11) FIG. 2 illustrates upper disc 101 and wear plate 104 removed for illustrative purposes. Lower disc 102 is protected from wear by three lower wear plates 201. A distributor plate 200 is attached to a centre region of lower disc 102 and is configured to distribute the feed material received through aperture 104 and to protect the lower disc 102 from wear and impact damages caused by the abrasive contact with the feed material. Distributor plate 200 is modular and comprises three separate segments 205 arranged circumferentially around a central longitudinal axis 211 that extends through rotor 100 and is aligned substantially perpendicular to upper and lower discs 101, 102. Each segment 205 comprises a wear resistant insert 210 arranged at a perimeter region of distributor plate 200.

(12) Upper and lower discs 101, 102 are separated axially by a series of rotor wall sections 202 that extend vertically between discs 101, 102 and are positioned radially outside of the lower wear plates 201. Spatial gaps are provided between wall sections 202 to define outflow openings 204 through which the feed material is ejected by the centrifugal forces of the spinning rotor 100 to contact surrounding anvils (or retained material) that act to crush the material for subsequent discharge from the crusher.

(13) Referring to FIGS. 2 and 3, each wall section 202 is terminated at a leading edge side by a wear tip holder 208 that mounts a wear resistant tip 207. Holder 208 and tip 207 are also aligned substantially vertically to extend between the upper and lower discs 101, 102. Each wall section 202 further comprises a wear tip shield 212 positioned at an opposite trailing edge of wall section 202 to extend substantially vertically between the upper and lower discs 101, 102. Accordingly, material outflow regions 204 are defined circumferentially between each wear tip 207 (and tip holder 208) and an adjacent tip shield 212.

(14) Referring to FIG. 3, arrow R indicates the rotational direction of the rotor 100 during operation of the VSI-crusher. During operation of the rotor 100, a bed of material 300 is created against each of the three wall section 202 and on top of each plate 201 (only one bed 300 is illustrated for clarity). Bed 300, formed from material that has been fed to the rotor 100 and has been trapped inside it, extends from a rear support plate 209 to wear tip 207 (and holder 208). Each material bed 300 acts to protect the wall section 202, the plate 201 and the wear tip 207 from wear and provides directional control of the ejected material. Arrow A describes a typical passage of material fed to rotor 100 via central aperture 104 and ejected via outflow opening 204. As illustrated in FIG. 3, the flow of material passing through rotor 100 travels in contact with a single distributor plate segment 205 in a generally radially outward direction from central axis 211. That is, the flow of material does not pass over the transitions between individual segments 205. More specifically, the flow A of material passes over predominantly vertex 301 formed at the junction between distributor plate edges 302, 303. Accordingly, the edges 302, 303 and vertex 301 of each segment are subjected to enhanced levels of abrasion wear relative to radially inner or other circumferential regions spaced from each vertex 301 and edges 302, 303. Accordingly, the wear resistant insert 210 is located at each distributor plate segment 205 at the region of vertex 301 and edges 302, 303. Distributor plate 200 is supported at a raised position above lower disc 102 via a mount plate (the position of which is indicated generally by reference 206) positioned immediately and directly below the distributor plate 200. The mount plate is, in turn, bolted to lower disc 102 via a locating cap screw (not shown) and locking pin and bolt set.

(15) Referring to FIGS. 4 to 8, each distributor plate segment 205 comprises an upward facing surface 401 intended to be positioned facing towards upper disc 101 and a downward facing surface 402 for mounting against the mount plate 206. Each surface 401, 402 is defined by a pair of inner edges 406, 407 that are configured for positioning against the inner edges 406, 407 of a neighboring plate segments 205 to form the complete tessellated hexagonal shaped distributor plate 200. Surfaces 401, 402 are further defined by the radially outward facing edges 302, 303 that define a perimeter region of distributor plate 200. Each segment 205 comprises as a majority component, a main body 400. Main body 400 comprises a ductile iron alloy (alternatively turned ductile cast iron, nodular cast iron, spheroidal graphite iron, spherulitic graphite cast iron or SG iron). Main body 400 is formed as an iron alloy matrix comprising nodules of graphite and one or more nodulising elements such as magnesium for example. To provide enhanced wear resistance, cemented carbide granules 408 are embedded within the predominantly iron based main body 400 during casting to form a composite structure.

(16) Advantageously, the cemented carbide granules 408 are distributed non-uniformly through the depth of each segment 205 in a direction of axis 211 from upper surface 401 to lower surface 402. That is, granules 408 are concentrated at surface 401 so as to decrease in concentration towards surface 402. In particular, carbide granules 408 penetrate to a depth of approximately one third of the thickness of main body 400 in the axial direction from upper surface 401 to lower surface 402. The granules 408 are however distributed substantially uniformly in the plane of segment 205 substantially perpendicular to axis 211. Additionally, according to further embodiments, the granules 408 may have a higher concentration towards outer edge regions 302, 303. Furthermore, granules 408 may comprise a higher concentration within main body 400 at a region immediately surrounding wear resistant insert 210. Carbide granules 408 may comprise any form of metal carbide including by way of example titanium-carbide, zirconium-carbide, hafnium-carbide, vanadium-carbide, niobium-carbide, tantalum-carbide, chromium-carbide, molybdenum-carbide, tungsten-carbide, manganese-carbide, cobalt-carbide, nickel-carbide.

(17) As indicated, distributor plate 200 comprises three wear resistant inserts mounted at the uppermost plate surface represented in part by the upper segment surfaces 401. Each insert 210 is bonded to main body 400 during casting so as to bond and securely mount each insert 210 at each segment 205. Inserts 210 comprises a cemented tungsten carbide material that exhibits enhanced wear resistance relative to main body 400 and comprises a plate-like shape profile having a thickness (in the direction of axis 211) that is less than the thickness of main body 400. In particular, a thickness of each tile 210 is up to approximately one third of the thickness of main body 400. Insert 210 comprises an irregular heptagonal configuration in which five edges 403 are mounted and embedded internally within the main body 400 whilst two edges 404, 405 are radially outward facing away from axis 211 to be co-aligned with segment edges 302, 303 respectively. Insert 210 is further defined by an upward facing surface 409 and an opposed downward facing surface 410. Upper insert surface 409 is positioned coplanar with segment upper surface 401 so as to avoid the creation of any ridges at the upward spacing surface of distributor plate 200 that may otherwise deflect the flow A of material during rotation. This is achieved conveniently by the casting process in which insert lower surface 410 and edges 403 are bonded to the ductile iron main body 400. The inventors have observed that the bonded strength between insert 210 and main body 400 is enhanced due to the incorporation of the nodular graphite and/or carbide granules 408 within the ductile iron. This is advantageous as the centrifugal forces acting on insert 210 would otherwise facilitate detachment of the insert 210 during use. Insert 210 is specifically positioned at the region radially inside vertex 301 (and to each lateral side of vertex 301) such that upper surface 409 represents a contact region over which the majority of the feed material flows. In particular, due to its relative positioning, the majority of the material flow (A) leaves each segment 205 over and in contact with the two edges 404, 405. According to the specific implementation, a surface area of insert surface 409 relative to a surface area of segment upper surface 401 is in a range 10 to 50% and is preferably in a range 20 to 40%. The singular insert surface 409 therefore presents a significant portion of the upward facing surface 401 of each segment 205.

(18) As illustrated in FIGS. 4 to 8, each segment 205 comprises a pair of relatively short cylindrical support feet 411 configured to seat into mount plate 206 so as to rotatably lock distributor plate 200 within rotor 100.

(19) Each segment 205 further comprises a lower wear resistant inserts 412 positioned generally at segment downward facing surface 402. Each lower insert 412 is positioned to be facing mount plate 206 and provides redundancy protection for mount plate 206, lower disc 102 and hub 105 in the event of failure (cracking, excessive wear or fracture) of main body 400 and/or upper insert 210. Lower insert 412 is also positioned at a perimeter region of distributor plate 200 such that the majority of the lower insert 412 is positioned directly below upper insert 210. Each insert 210, 412 is separated in the axial direction by an intermediate region 413 of main body 400 to provide a tertiary layer structure at the region of edges 404, 405 and vertex 301 in the direction of axis 211. The relative thicknesses in the axial direction of upper insert 210, main body region 413 and lower insert 412 are substantially equal. Accordingly, a general thickness of the upper and lower insert 210, 412 is approximately equal.

(20) Referring to FIGS. 7 and 8, each lower insert 412 comprises a white iron alloy (alternatively term white cast iron) that typically includes a cementite phase. Unlike the upper insert 210, lower insert 412 is bonded to an underside region of main body 400 using a suitable adhesive or other chemical bonding agent. According to further specific implementations, lower insert 412 may be attached via mechanical means such as bolts, plugs, screws or pins extending axially between insert 412 and main body 400. According to the specific implementation, each lower insert 412 comprises a pair of radially outward facing edges 702, 703 configured for positioning axially below upper insert edges 404, 405. The remaining perimeter of lower insert 412 is defined by a continuous curved and/or angled inner edge 704. A recess (or groove) 800 is indented into main body 400 to extend axially inward from segment lower surface 402. A depth of recess 800 in a direction of axis 211 is slightly greater than a thickness of lower insert 412 such that a downward facing surface 700 of insert 412 is recessed relative to segment surface 402. The adhesive or bonding agent (not shown) is provided between an upper facing surface 701 of insert 412 and the segment downward facing surface 402 within recess 800. The bonding agent may also be provided between the opposed insert edges 704 and edges 801 that in part, define recess 800.

(21) Insert 412 comprises a generally ‘fish-tail’ shape profile so as to wedge into recess 800 and be resistant to detachment due to the centrifugal forces created by the spinning rotor 100. That is, each insert 412 comprises a pair of tail segments 706 that extend laterally outward and rearward from an insert waist region 707. Accordingly, a radially inner region of each recess 800 comprises a flange region 705 projecting inwardly within recess 800 and a flared region 708 to mate respectively with the waist 707 and tail segments 706. Accordingly, flange 705 is configured to abut each tail segment 706 so as to lock insert 412 in position within recess 800 by mechanical frictional forces.

(22) Accordingly, due to the specific choice of constituent materials for the distributor plate segments 205, upper and lower inserts 210, 412 and the relative shape, size and position of the inserts 210, 412 at the respective upper and lower surfaces 401, 402 the present distributor plate 200 is optimised for wear resistance in response to a continuous flow of material in direction A. In particular, under controlled test conditions, the present distributor plate 200 achieved a wear life of over 620 hours in contrast to a conventional distributor plate that achieved only 125 hours.