Impact crusher wear components including wear resistant inserts bonded therein

A wear component for use in an impact crusher having a forward depression on the face of the wear component which is exposed to aggregate wear. Wear resistant inserts, for example cemented tungsten carbide inserts, are bonded within the forward depression to prevent rapid abrasion of the wear component. Joints are formed between wear resistant inserts and joints are also formed between wear resistant inserts and the wear component. Bonding material fills the joints to further secure the wear resistant inserts and to prevent crack propagation.

FIELD OF THE INVENTION

The present invention relates to impact crusher wear components, and more particularly relates to the use of wear resistant inserts bonded in wear components such as anvils, impellers, and table plates.

BACKGROUND INFORMATION

A major segment of the aggregate industry employs Vertical Shaft Impact (VSI) crushers to reduce large earth materials to smaller sized aggregate. VSI crushers rely on centrifugal force to disperse large aggregate through the crusher, and to impact the aggregate against a wide variety of impact crusher components to break up, reduce in size, and ultimately eject from the crusher, aggregate composed of desired shapes, sizes and consistency. Movement of abrasive materials such as aggregates through equipment causes abrasion and fatigue which wears out many components of the equipment. Efforts have been devoted to improvements in the design and construction of components of impact crushers to reduce the cost of acquiring and operating crushers, to enhance wear resistance of the component parts of crushers, and to facilitate rapid replacement of worn parts of crushers to enable the user of crushers to lose the least possible amount of time during which a crusher is inoperative due to worn parts.

The main components used to crush aggregate in a VSI crusher are impellers and anvils. An impeller of an impact crusher rotates to receive and hurl aggregate against one or more crusher components generally known in the art as anvils. This reduces the size of the aggregate and causes significant wear on impellers and faces of anvils.

Many in the industry have attempted to combat wear of impellers and anvils by protecting these components with hardened material. The cost of most hard materials, such as tungsten carbide, makes it cost prohibitive to make an entire anvil or impeller from this material. For this reason, only surfaces exposed to the abrasion contain hard material while the remainder of the piece is made of less expensive material such as steel or cast iron. U.S. Pat. No. 7,028,936, having the same inventor and assignee as the current application, suggests casting carbide bars into an air-hardened steel alloy base. U.S. Pat. No. 5,954,282 to Briske suggests threading separate wear bars into a base. U.S. patent application Ser. No. 9/921,430 teaches press fitting separate wear bars into a base.

However, in these designs, gaps remain between the wear resistant surfaces so that the milder base surface is still exposed to abrasion. This can result in what is commonly termed “wash out”. Wash out occurs when so much of the base surface has been eroded that it can no longer support the wear resistant piece. This causes the wear resistance piece to be dislodged from the base leaving the softer base material exposed to quick abrasion.

The present invention has been developed in view of the foregoing.

SUMMARY OF THE INVENTION

The present invention provides an anvil for use in a crusher. In one embodiment, an anvil has a forward face, which is the primary wear surface on the anvil. The forward face has a forward depression formed therein. Hardened material inserts are fixed within the forward depression using a bonding material that fills joint between the inserts and the forward depression. For example, the hardened inserts may be cemented tungsten carbide and the bonding material may be an epoxy adhesive. The cemented tungsten carbide inserts form an array within the forward depression. Narrow joints, less that 0.007 inch, are formed between the inserts and the depression sides and between inserts.

An aspect of the present invention is to provide an anvil for use in an impact crusher comprising an anvil body having a forward depression, an array of wear resistant inserts within the forward depression of the base; and a bonding material attaching the wear resistant inserts to the forward depression of the base.

Another aspect of the present invention is to provide a method of making an anvil for an impact crusher comprising the steps of providing an anvil body having a forward depression and bonding an array of wear resistant inserts in the forward depression of the anvil.

DETAILED DESCRIPTION

Referring now toFIG. 1, a vertical shaft impeller rock-crushing machine10includes an impeller turntable12, which revolves at a high speed about a central shaft (not shown). Impeller blade shoes14are affixed to the turntable12at regular intervals along its surface. Rock or other aggregate (not shown) drops onto the turntable from a funnel16located above the turntable, and the centrifugal force caused by the rotating shoes14slings the rock outwards causing it to strike a series of anvils18and be crushed. Initially, the rock or aggregate falls on a central feed body20of the turntable12, but as the turntable12rotates, the rock spreads outward along the central feed body20forming streams of material, particulate in nature, which flow across the wear surfaces of each of the impeller blade shoes14and out into the anvils18. Anvils18are aligned at specifically designed angles relative to the radius of the turntable12. The orientation, geometry and angle of the impact surface influences the size and distribution of the aggregate produced. The anvils18are mounted within the crusher by methods well known in the industry. In accordance with the present invention, some or all of the anvils18may be provided with an array of wear resistant inserts40bonded within a depression on the wear surface of each anvil18, as more fully described below. A vertical shaft impact crusher and the components thereof are well described in U.S. Pat. No. 7,028,936, which is hereby incorporated by reference in its entirety.

FIGS. 2 and 3illustrate an anvil18in accordance with an embodiment of the present invention. It should be appreciated that the employed materials, general construction and method of making the anvil18and are applicable to other components on any equipment exposed to material flow in any industry, including construction and mining. It is contemplated for instance that impellers and table plates on the impeller crusher could also be made in accordance with the following description.

The anvil18has a forward face26, which is exposed to the aggregate streams within the crusher10, and rear face24that mounts to the crusher10. A forward depression28is formed in the forward face26of the anvil18. The forward depression28includes a bottom surface30and side surfaces32. The forward depression28has a depth D as shown inFIG. 3which may typically range from 0.25 inch to 0.75 inch, for example about 0.5 inch. An array40of wear resistant inserts42is bonded within the forward depression28. A bonding material54may be used to securely hold the wear resistant inserts42in place.

The anvil body22may be constructed of materials such as air hardened, high carbon steel or any other alloy familiar to the industry. However, the array of wear resistant inserts40within the forward depression lessens the need to use more expensive wear resistant, alloy or high carbon steels in the anvil body22. The wear resistant inserts42allow for the use of less expensive metal alloys for the anvil body22since the anvil body22is protected by the wear resistant inserts42and not subject to high abrasion. It is also contemplated that the anvil body22may be constructed from a white cast iron, a low alloy steel or from a composite of steels where portions of the anvil body22around the forward depression28are harder steel than those portions closer to the rear face24of anvil18.

The wear resistant inserts42may be made from any suitable material such as cemented tungsten carbide. For example, cemented tungsten carbide for use in this application may have 6% cobalt, with properties of 88 to 93 HRA. The cobalt may fall within the range of 5.5-16.0 wt. %. For applications requiring increased wear resistance the cobalt may comprise 5.5-9.0 wt. % of the material; for other applications requiring better toughness it might fall within the range of 11.0-14.0 wt. %. While cemented tungsten carbide may be used for this application, other super hard wear resistant materials such as ceramics and or cermets may be used. For example, chromium carbide coated metals and other cermets where titanium carbide or vanadium carbide are added to tungsten carbide may be used. Ceramics appropriate for this application may include aluminum-based, silicon-based, zirconium-based and glass ceramics.

The wear resistant inserts42shown inFIGS. 2 and 3are arranged in an array of wear resistant inserts40within the forward depression28. Each wear resistant insert42has a wear face44exposed to the aggregate streams and a bonded face (not shown) in contact with the bonding material54, facing the forward depression. The wear face44and bonded face46of a wear resistant insert42may be generally flat. A backing joint48is formed between the bonded faces46and the bottom surface30of the forward depression28in the anvil18. The backing joint48is filled with bonding material54. The backing joint48typically has a thickness of from 0.005 inch to 2.000 inches, for example, about 1.000 inch. The wear resistant inserts42have sides that abut the sides of adjacent wear resistant inserts42to form insert joints52. Insert joints52typically have a width of from 0.005 inch to 0.500 inches, for example, about 0.006+/−0.001 inch. A peripheral joint50is formed between wear resistant inserts42and sides32of the forward depression28. The peripheral joint50typically has a width of from 0.005 inch to 0.500 inch, for example, from 0.005 inch to 0.015 inch.

FIG. 2shows an example of an arrangement of twenty rectangular wear resistant inserts42placed in a series of rows and columns. Such arrangements are beneficial because they provide an easily manufactured standard shape for the wear resistant inserts42that minimizes the length of joints created between inserts. Insert geometries may be varied provided good fit and designed joints can be maintained between adjacent inserts and between wear resistant inserts42and the forward depression28. For example, the wear resistant inserts42may be triangular and have only three sides or hexagonal with six sides. In another embodiment, the wear resistant inserts may have an interlocking geometry, such as a tongue and groove design or a shiplap joint.

The wear resistant inserts42can be of varied sizes. In one embodiment each insert is 1″×1″×⅝″ deep. Length and width, shown as LIand WIrespectively inFIG. 2, can typically range from 0.5 to 6 inches, for example 1 inch. The thickness, shown as TIinFIG. 3, can typically range from 0.25 to 3 inches. The number of wear resistant inserts42required depends on the size of the anvil18and the size of the wear resistant inserts42used. LAinFIG. 2refers to the overall length of the array of wear resistant inserts40. LAis typically 3 inches to 10 inches. WAinFIG. 2refers to the overall width of the array of wear resistant inserts40. WAis typically 3 inches to 10 inches. It is common in the crusher industry to quantify anvils18by mass. The invention applies to all sizes of anvils, but has specific application to 15 pounds to 75 pounds range of anvils.

In one embodiment, the bonding material54is a thermoset epoxy adhesive capable of bonding to metals. The epoxy forms a strong permanent bond between the forward depression in anvil28and the wear resistant inserts42. The bonding material50is present within the insert joints52and the peripheral joint50. This provides bonding between the wear resistant inserts42. The epoxy may be introduced into the insert joints52and peripheral joint50by applying a change of pressure and increased temperature to the bonding material50and wear resistant inserts42prior to setting or curing of the bonding material. Control of atmospheric pressure and type of gas is dependent on the type of bonding agent and process used. Other materials capable of bonding metals may be used as the bonding material. Other suitable bonding materials capable of chemical adhesion may include brazing alloys and airset epoxies. Suitable methods of attachment may also include mechanical or welded type attachments such as bolting or plug welding.

The insert joints52between wear resistant inserts42serve to prevent crack propagation. It is common for hard materials such as cemented tungsten carbide to crack. A single crack in a one-piece insert design could cause the entire anvil to quickly fail. Whereas, a crack in an insert that is a small part of a larger array will affect only the cracked insert which is less likely to impact on the life of the anvil. This is the reason using many smaller wear resistant inserts42with insert joints52between is preferable to using one large wear resistant insert42to fill the forward depression28.

The use of multiple wear resistant inserts42also allows anvils to be tailored to be application specific. In one embodiment, inserts are appropriately selected based on the material hardness and toughness required for the particular application. For example, the center sections of an anvil18within a VSI crusher will usually experience higher wear than the upper and lower sections. Therefore, tungsten carbide inserts with Co in the range of 5.5-9.0 wt. % could be used in a center portion of the forward depression28of the anvil18while a less expensive insert may be used in the upper and lower portions of the forward depression28of the anvil18. This flexibility in design will increase the performance of the anvils18while saving costs associated with the manufacture of anvils18.

In an embodiment shown inFIG. 4, the wear resistant inserts are arranged in two layers. An interior layer60operates as a safety barrier should the outer layer62wear through or become dislodged. The layers60,62are installed in a staggered pattern to counter erosion of joints.

In another embodiment shown inFIG. 5, the wear resistant inserts42are thicker in high wear areas. In this embodiment, the recess28is congruently shaped to accommodate thicker wear resistant inserts42in the high wear areas. It should be appreciated that the thicker inserts may be configured in ways other than that shown inFIG. 5. For example, the thicker inserts may be in the center of the anvil or more or less rows of inserts may be needed.

As mentioned above, the anvil angles relative to a radius of the turntable12determine the size and distribution of the aggregate produced. Conventional anvils and those subject to “wash out” tend to wear quickly and unevenly. Uneven wear of the forward surface of an anvil18causes the anvil angle to change causing undesired aggregate size and distribution. The anvils of the present invention take longer to show any signs of wear. Accordingly, the anvils of the present invention produce a more consistent and predictable reduction in aggregate size and particle distribution.