Reducing component for a comminution machine

A reducing component is disclosed herein. The reducing component includes a block-style reducer including a height, a width and a depth. The block-style reducer includes first and second ends separated by the height, first and second sides separated by the width and front and back sides separated by the depth. The block-style reducer also includes a first reducing edge that extends across the width of the block-style reducer at a location adjacent to the first end of the block-style reducer. The reducing component also includes a blade-style reducer that projects forwardly from the block-style reducer at a location adjacent the second side of the block-style reducer. The blade-style reducer includes a second reducing edge that extends primarily along the height of the block-style reducer.

This application is a National Stage Application of PCT/US2010/047702, filed on 2 Sep. 2010 and which application is incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications.

TECHNICAL FIELD

The present disclosure relates generally to reducing components for comminution machines. In particular, the present disclosure relates to reducing components for comminution machines such as grinders and chippers.

BACKGROUND

Comminution machines are used to reduce waste materials such as trees, brush, stumps, pallets, root balls, railroad ties, peat moss, paper, wet organic materials, fibrous materials such as empty fruit bunches and the like. Two common types of comminution machines include grinders and chippers. Grinders are typically configured to reduce material through blunt force impactions. Thus, the reduced material product generated by grinders generally has a ground, flattened texture with relatively high fines content. This type of reduced material is typically used as mulch. In contrast to the blunt force action used by grinders, chippers reduce material through a chipping action. The reduced product generated by chippers preferably has a relatively small percentage of fines. This type of chipped reduced product can readily be used as fuel for a burner since the material is more flowable than ground reduced material and can easily be handled by the material processing equipment used to feed fuel to a burner.

Grinders typically include reducing hammers on which replaceable grinding cutters (i.e., grinding tips or grinding elements) are mounted. Grinding cutters generally have relatively blunt ends suitable for reducing material through blunt force impactions. Screens are often used to control the size of the reduced material output from grinders. In contrast to the grinding cutters used on grinders, chippers typically include relatively sharp chipping knives configured to reduce material through a cutting/slicing action as opposed to a grinding action.

SUMMARY

Aspects of the present disclosure relate to reducing components for a comminution machine. In certain embodiments, the reducing components can include block-style reducers combined with blade-style reducers.

DETAILED DESCRIPTION

With reference now to the various figures in which identical components are numbered identically throughout, a description of various exemplary aspects of the present disclosure will now be provided. The disclosed embodiments are shown in the drawings and described with the understanding that the present disclosure is to be considered an exemplification of certain inventive aspects and is not intended to limit the inventive aspects to the embodiments disclosed.

Comminution machines in accordance with the principles of the present disclosure can include rotary reducing units used to reduce material through comminution actions such as grinding, cutting, chopping, slicing, chipping, etc. The rotary reducing units can include carriers (e.g., drums or other carriers as disclosed at U.S. Pat. Nos. 7,204,442; 5,507,441; 7,213,779; and 6,840,471 that are hereby incorporated by reference) that carrying a plurality of reducing components (e.g., edges, grinding members, cutters, plates, blocks, blades, bits, teeth, hammers, shredders or combinations thereof) around rotational cutting paths surrounding central axes of rotation of the carriers. In use, the carriers are rotated about their axes to cause the reducing components to impact material desired to be reduced thereby causing reduction of the material via one or more comminution actions. Screen can be provided at least partially surrounding the rotary reducing units for providing additional comminution action and for controlling the size of the reduced material output from the comminution machines. Example comminution machines in accordance with the principles of the present disclosure can include tub grinders, horizontal grinders, chippers, shredders or other material reduction machines.

FIGS. 1 and 2illustrate an example reducing component20in accordance with the principles of the present disclosure. The reducing component20includes a block-style reducer22in combination with a blade-style reducer24positioned at one side of the block-style reducer22. In the embodiment ofFIG. 1, the blade-style reducer24is removably fastened to one side of the block-style reducer22via fasteners26. However, in other embodiments, the blade-style reducer24can be integrally formed/cast as a single piece with the block-style reducer22or otherwise fixedly connected (e.g., welded) to the block-style reducer22.FIGS. 8-11show an alternative reducing component20ahaving a block-style reducer22aintegrally formed as a single piece with a blade-style reducer24a.

The reducing component20ofFIGS. 1 and 2is adapted to be mounted to a leading face30of a bar-style hammer32via fasteners34. However, it will be appreciated that in other embodiments the reducing component20can be mounted to other styles of hammers or can be mounted directly to drums or other types of rotational carriers.

For ease of description, reference x, y and z axes have been provided atFIG. 1. The x, y and z axes are all perpendicular to one another. The block-style reducer22is generally rectangular and includes a height h1that extends along the z-axis, a width w1that extends along the y-axis and a depth d1that extends along the x-axis. The height h1is larger than the width w1and the width w1is larger than the depth d1. The block-style reducer22includes first and second sides36,38separated by the width w1. The block-style reducer22also includes front and back sides40,42separated by the depth d1. The block-style reducer22further includes first and second ends44,46separated by the height h1.

Openings48extend through the depth d1of the block-style reducer22for receiving the fasteners34used to secure the reducing component20to the hammer32. The fasteners34extend along the x-axis. Openings50extend through the width w1of the block-style reducer22for receiving the fasteners26used to secure the blade-style reducer24to the block-style reducer22. The fasteners26extend along the y-axis.

The front side40of the block-style reducer22can be referred to the “reducing side” or “leading side” of the block-style reducer22. During the reduction of material, the block-style reducer22is moved such that the front side40leads the block-style reducer and impacts the material desired to be reduced. The front side40of the block-style reducer22includes a main central region52(i.e., a main central face) through which the openings48extend. The openings48are countersunk at the main central region52for receiving heads of the fasteners48. The front side40also includes reducing edges56,58positioned on opposite sides of the main central region52. The reducing edges56,58extend across the width w1of the block-style reducer22. The reducing edges are parallel to one another and both extend along the y-axis. The first reducing edge56is formed by a first wedge-like element60that projects forwardly from the main central region52at a location adjacent to the first end44of the block-style reducer22. The second reducing edge58is formed by a second wedge-like element62that projects forwardly from the main central region52at a location adjacent to the second end46of the block-style reducer22. The edges56,58are located at front-most portions of the wedge-like elements60,62and can have a rounded/blunt configuration adapted for grinding material desired to be reduced. The wedge-like elements60,62are each formed by surfaces64,66(seeFIG. 5) that converge as the surfaces64,66extend forwardly toward the edges56,58. In other embodiments, the edges56,58can be sharp edges such as knife edges adapted for chipping material being reduced.

FIG. 15shows an alternative fastening arrangement for securing a block-style reducer22′ to one of the hammers32. The block-style reducer22′ includes internally threaded openings48′ that receive threaded ends33′ of fasteners34′ used to secure the block-style reducer22′ to the hammer32. The fasteners34′ extend through openings in the hammer32and heads of the fasteners are protected behind back sides of the hammers32.

The blade-style reducer24includes a height h2that extends along the z-axis, a width w2that extends along the y-axis and a depth d2that extends along the x-axis. The height h2is larger than the depth d2and the depth d2is larger than the width w2. The blade-style reducer24includes first and second sides70,72separated by the width w2. The blade-style reducer24also includes front and back ends74,76separated by the depth d2. The blade-style reducer24further includes first and second ends78,80separated by the height h2. The front end74of the blade-style reducer24comprises a reducing edge82that extends along the z-axis and along the height h2. The reducing edge82has opposite first and second ends84,86(seeFIG. 5) separated from one another by the height h2. In one embodiment, the reducing edge82can include a knife edge adapted for cutting, chipping or slicing material desired to be reduced. In one embodiment, the reducing edge82is sharper than the reducing edges56,58. The reducing edge82is formed by a wedge-like element85(seeFIG. 2) having surfaces that converge as the surface extend forwardly toward the reducing edge82. In other embodiments, the reducing edge82can have a blunt configuration or a squared configuration.

The blade-style reducer24mounts to the second side38of the block-style reducer22. As shown atFIG. 2, the wedge-like element85projects forwardly from the front side40of the block-style reducer22with the reducing edge82extending parallel to the height h1of the block-style reducer22. When viewed in plan view from the front of the assembly, the reducing edge82is perpendicular to the edges56,58. The reducing edge82is forwardly offset a distance d with respect to the edges56,58(seeFIG. 2). A forward portion86of the first side70of the blade-style reducer projects forwardly beyond the main central region52of the front side of the block-style reducer22such that the front side of the block-style reducer22and the forward portion86cooperate to define a pocket88(seeFIG. 2). The pocket88has an open side90adjacent the first side of the block-style reducer22and a closed side92adjacent the second side of the block-style reducer22.

FIG. 3schematically shows a comminution machine100(e.g., a horizontal grinder) having a rotational reducing unit102including a plurality of the reducing components20. The comminution machine100also includes an in-feed system104(e.g., a conveyor) for conveying material desired to be reduced to the reducing unit102, and a discharge system106for carrying reduced material away from the reducing unit102. In use of the comminution machine100, the rotational reducing unit is rotated (e.g., by a drive mechanism) about a central axis108causing the reducing components20to be spun along a reducing perimeter RP (e.g., an outermost reducing diameter, seeFIG. 5) that surrounds the axis of rotation108. While the rotational reducing unit102is rotating, material desired to be reduced is loaded into the in-feed system104which conveys the material toward the rotating reducing unit102and into the reducing perimeter RP. When the material intersects the reducing perimeter RP, the material is impacted by the reducing components20and initially reduced. Contact between the material and the reducing unit102forces the material past an anvil110(one example of a suitable anvil is described in more detail in U.S. Pat. No. 7,461,802 which is incorporated herein by reference) into a comminution chamber112. The comminution chamber112is defined between the reducing unit102and a sizing screen500. Within the comminution chamber112; the material is ground and sliced by the reducing components20and reduced material passes through openings in the sizing screen500to the discharge system106. The discharge system106carries the reduced material away from the comminution chamber112to a collection location.

Referring toFIG. 4, the reducing unit102includes a reducing component carrier in the form of a cylindrical drum116that is rotatable in a direction118about the axis of rotation108. A plurality of the hammers32are mounted to the drum116. The hammers32have end portions119that project radially outwardly from an outer cylindrical skin120of the drum116. The reducing components20are mounted to leading faces of the end portions of the hammers32. When the drum116is rotated about the axis108, the hammers32and the reducing components20mounted thereto are carried around the axis of rotation108with outermost portions of the reducing components20defining the reducing perimeter RP of the reducing unit102. As shown atFIG. 5, the outermost portions of the reducing components include the first reducing edges56of the block-style reducers22and the first ends84of the reducing edges82of the blade-style reducers24. The entire lengths of the first reducing edges56are positioned at or in close proximity to the reducing perimeter RP so that the entire lengths of the first reducing edges56define the reducing perimeter RP. In contrast, the reducing edges82are oriented so that the lengths of the reducing edges82to extend inwardly from the reducing perimeter RP and only the first ends84are positioned at and define the reducing perimeter RP.

As shown atFIG. 5, the first reducing edges56of the block-style reducers22are positioned at the reducing perimeter and the second reducing edges58are inwardly offset from the reducing perimeter RP. The second reducing edges58are provided on the block-style reducers so that when the first reducing edges56become worn, the block-style reducers22can be removed from the hammers32and then remounted on the hammers32in a reverse configuration with the second reducing edges58positioned at the reducing perimeter RP.

FIG. 6is a plan view of an example configuration of the screen500suitable for use with the reducing unit102. The screen500is adapted to at least partially to circumferentially surround the rotational reducing unit102. The screen500includes a screening region502having an upstream-most boundary504separated from a downstream-most boundary506by an upstream-to-downstream screen dimension508. When the screen500is mounted within a comminution machine, the upstream-to-downstream dimension is parallel to a direction of travel518of the material reducing components20of the comminution machine. The screening region502also has a first side boundary510(e.g., left side boundary) separated from a second side boundary512(e.g., a right side boundary) by a cross-screen dimension514. The cross-screen dimension514is transversely oriented relative to the upstream-to-downstream screen dimension508.

The screening region502includes a plurality of sizing slots516circumscribed by the boundaries504,506,510and512of the screening region502. The sizing slots516have slot lengths SL and slot widths SW. The sizing slots516are elongated along the slot lengths SL such that the slot lengths SL are longer than the slot widths SW. The slot lengths SL of the sizing slots516are shown extending primarily along the upstream-to-downstream screen dimension508between the upstream-most boundary504and the downstream-most boundary506. The slot widths SW are shown extending primarily along the cross-screen dimension514between the first side boundary510and the second side boundary512. The sizing slots516are spaced-apart from one another (e.g., by lands) along the cross dimension514. The sizing slots516are arranged inside the boundaries504,506,510,512in a single row of parallel sizing slots that are spaced-apart from one another along the cross-screen dimension514. The sizing slots516are continuously open (i.e., open without interruption) along their slot lengths.

The continuously open slot lengths of the sizing slots516preferably traverse a significant portion of the total length of the upstream-to-downstream screen dimension508. The extended open construction of the sizing slots516, which extends primarily in the upstream-to-downstream direction, assists in reducing the likelihood of plugging. Certain of the slots in accordance with the principles of the present disclosure have continuously open slot lengths that traverse more than 50 percent of the upstream-to-downstream screen dimension508. Other slots in accordance with the principles of the present disclosure have continuously open slot lengths that traverse at least 75 percent of the upstream-to-downstream screen dimension508. Still other slots in accordance with the principles of the present disclosure have continuously open slot lengths that traverse at least 90 percent of the upstream-to-downstream screen dimension508. Further slots in accordance with the principles of the present disclosure have continuously open slot lengths that traverse the entire length of the upstream-to-downstream screen dimension508(i.e., 100 percent of the upstream-to-downstream screen dimension508).

Referring toFIG. 6, slots of various lengths are shown. For example, slots516ahave continuously open slot lengths that traverse the full length of the upstream-to-downstream screen dimension508. Thus, upstream ends of the slots516adefine the upstream-most boundary504of the screening region502and downstream ends of the slots516adefine the downstream-most boundary506of the screening region502. Slots516bhave continuously open slot lengths that traverse 50 to 90 percent of the upstream-to-downstream screen dimension508. Slots516chave continuously open lengths that traverse less than fifty percent of the upstream-to-downstream screen dimension508. The slots516a,516band516care shown parallel to each other end and are shown extending primarily along the upstream-to-downstream screen dimension508.

As used herein, the reducing component travel direction518is the direction, viewed in plan view (as shown atFIG. 6), in which the reducing components20move as the carrier carries the material reducing components along the cutting path from the upstream-most boundary to the downstream-most boundary of the screening region502. The slot lengths SL of the sizing slots516are orientated at oblique angles θ relative to the reducing component travel direction518. As shown atFIG. 6, the oblique angles θ are determined/measured from the plan view of the screen. In certain embodiments, the oblique angles θ are less than 45 degrees. In other embodiments, the oblique angles θ are in the range of 5-30 degrees. In still other embodiments, the oblique angles θ are in the range of 10-25 degrees. Similar to earlier disclosed embodiments, the slots can have a length to width ratio of at least 10 to 1, or at least 20 to 1, or at least 30 to 1.

It will be appreciated that the desired size of the angle θ is dependent upon the material being processed and the desired characteristics (e.g., size, flow characteristic, etc.) of the reduced material exiting the screen. For fibrous materials, it is generally preferred for the slots516to be obliquely angled relative to the reducing component travel direction518. However, in other embodiments, the continuously open lengths of the sizing slots may be parallel to the reducing component travel direction518.

The sizing slots516have upstream slot-defining surfaces522that are opposed by downstream slot-defining surfaces524. The upstream and downstream slot-defining surfaces522,524are parallel to the slot lengths. As shown atFIG. 7, the slot-defining surfaces522,524extend through the screen500from an inside surface526of the screen500to an outside surface528of the screen500. The inside surface526of the screen500preferably faces toward the rotational reducing unit and circumferentially surrounds at least a portion of the rotational reducing unit.

Referring toFIG. 7, the front sides40of the block-style reducers22face primarily in the reducing component travel direction518(i.e., in a downstream direction) when the reducing components20are moved along the inside surface526of the screen500. Movement of the reducing components20along the inside surface the screen is caused by rotation of the rotational cutting unit102in direction118about axis108thereby causing the reducing components to sweep along the reducing perimeter RP. As the reducing components20move along the reducing perimeter RP, the reducing components20sweep across the screening region502in an upstream-to-downstream direction. The reducing edges56of the reducing components20extend primarily along the axis of rotation108of the rotational reducing unit102. The reducing edges56can also be described as extending primarily along the screen cross-dimension514and/or extending primarily along the slot widths SW. The blade-style reducers24project outwardly from the front sides40of the block-style reducers22in the reducing component travel direction518. The forward portions of the first sides70of the blade-style reducers24face primarily toward the first side boundary510of the screening region502. The blade-style reducers24are preferably positioned adjacent the sides of the hammers32that are closest to the second side boundary512of the screening region502. In this way, the first sides70of the blade-style reducers24can be positioned to oppose the downstream slot-defining surfaces524of the slots516.

The reducing edges82of the blade-style reducers24are shown extending primarily along radial axes of the hammers32. The edges82can also be described as extending primarily radially outwardly from the inner surface526of the screen500and/or as extending primarily radially relative to the drum and/or the axis of rotation108of the rotational reducing unit102. The reducing edges82of blade-style reducers24are positioned forwardly with respect to the reducing edges56of the block-style reducers22. Thus, the reducing edges82lead the reducing edges56when the reducing components20are moved along the inside surface526of the screen500during reducing operations.

As shown atFIG. 7, the oblique angling of the sizing slots516relative to the reducing component travel direction518causes the slots516to extend in a first lateral direction580as the slots516traverse the upstream-to-downstream dimension508in downstream direction. The first sides70of the blade-style reducers24face primarily in a second lateral direction582that is opposite from the first lateral direction580. The first sides70also oppose the downstream slot-defining surfaces524of the sizing slots516. Similarly, the front sides40of the block-style reducers22face at least partially toward and oppose the downstream slot-defining surfaces524of the sizing slots516. The open sides90of the pockets88of the reducing components20face in the second lateral direction582. This pocket configuration assists in encouraging material being reduced to be forced against the downstream slot-defining surfaces524of the sizing slots516, For example, the configuration of the pockets inhibits material from flowing off of the front sides40of the block-style reducers22in the first lateral directions580and allows material to flow off of the front sides40of the block-style reducers22in the second lateral directions582. This causes the material to be encouraged in the second lateral direction582and forced against the downstream slot-defining surfaces524. It will be appreciated that the second lateral direction582opposes the downstream slot-defining surfaces524.

During material reduction, the reducing components20are swept circumferentially along the inner surface526of the screen500with a gap/clearance between the reducing perimeter RP and the inner surface526of the screen. In certain embodiments, the gap is at least 0.25 inches. In other embodiments, the gap is in the range of 0.25-0.5 inches. In the depicted embodiment, no portions of the reducing components pass through or otherwise enter the sizing slots516. In other words, the material reducing perimeter RP is inwardly offset from the inner circumferential surface526of the screen500such that no portions of the material reducing components enter the sizing slots during material reduction. In the depicted embodiment, the material reducing components20have reducing component widths which extend primarily along the slot widths and are larger than the slot widths.

It will be appreciated that reducing components and reducing units in accordance with the principles of the present disclosure can be used with comminution machines (e.g., horizontal grinders, vertical grinders, tub grinders, chippers, etc.) having various types of in-feed and discharge systems.FIG. 12shows the reducing component102incorporated into a tub grinder600. Further details of the tub grinder in-feed and discharge systems are disclosed at U.S. Pat. No. 5,950,942, which is incorporated by reference herein in its entirety. It will also be appreciated that reducing components and reducing units in accordance with the principles of the present disclosure can also be used with a variety of different types/styles of screens having a variety of types/shapes of sizing openings.FIG. 13shows reducing components20used in combination with a screen700having a stepped inner face702and generally rectangular (e.g., generally square) sizing openings704.FIG. 14shows reducing components20used in combination with a screen800having a smooth inner face802and generally rectangular (e.g., generally square) sizing openings804.

As used herein, the phrase “primarily along” a reference axis, dimension or structure means for the most part along (i.e., with 45 degrees of) the reference axis, dimension or structure. Also, the phrase “extending primarily radially” with respect to a reference axis, dimension or structure means extending for the most part in a radial direction from or toward from the reference axis, dimension or structure. Also, the phrase “generally parallel” means parallel or almost parallel. Further, the phrase “generally perpendicular” means perpendicular or almost perpendicular.

From the foregoing detailed description, it will be evident that modifications and variations can be made in the machine of the disclosure without departing from the spirit and scope of the disclosure.