Discharge grates for reduction mills

Abstract

Discharge grates and grate components of reducing equipment have reduced amounts of material to provide lower costs, lower weight, and less scrap while still providing adequate resistance to bending, deflection, and/or warping and suitable material discharge.

Claims

1. A discharge grate component for use in forming a discharge grate in a reducing machine, the discharge grate component comprising: only two spaced apart longitudinal grate elements; a plurality of spaced apart transverse grate elements that intersect the two longitudinal grate elements to define a curved working surface and form a plurality of discharge openings; and only one longitudinal support beam positioned outward of the intersecting longitudinal and transverse grate elements to provide support for the discharge grate component; wherein the two spaced apart longitudinal grate elements, the plurality of spaced apart transverse grate elements and the one longitudinal support beam are fixed together for assembly as a unit into the reducing machine.

2. A discharge grate component in accordance with claim 1 wherein a plurality of openings extends transversely through the longitudinal support beam to enable flow-through of material from the discharge openings.

3. A discharge grate component in accordance with claim 1 wherein the longitudinal support beam has an arched structure.

4. A discharge grate component in accordance with claim 1 wherein each of the two spaced apart longitudinal grate elements and the longitudinal support beam have an angular orientation relative to a radial direction relative to the radius of curvature, and the angular orientation of the longitudinal support beam is independent of the angular orientation of the two spaced apart longitudinal grate elements.

5. A discharge grate component in accordance with claim 1 wherein each of the plurality of spaced apart transverse grate elements have support extensions that extend beyond an exterior surface of one of the at least two spaced apart longitudinal grate elements and the longitudinal support beam connects to each of the support extensions.

6. A discharge grate component in accordance with claim 1 including two adjacent exterior transverse grate elements that extend transversely beyond one side of at least one of the two spaced apart longitudinal grate elements such that the two adjacent exterior transverse grate elements form one-half of an exterior discharge opening with said one side of the respective longitudinal grate element.

7. A discharge grate component in accordance with claim 6 wherein the two adjacent exterior transverse grate elements align with the plurality of spaced apart transverse grate elements.

8. A discharge grate for use in a reducing machine, the discharge grate comprising: at least two spaced apart longitudinal grate elements; a plurality of spaced apart transverse grate elements that intersect the at least two of the longitudinal grate elements define a curved working surface and form a plurality of discharge openings; two adjacent exterior transverse grate elements that extend transversely beyond one side of at least one of the longitudinal grate elements such that the two adjacent exterior transverse grate elements form one-half of an exterior discharge openings with said one side of the respective longitudinal grate element, wherein the two adjacent exterior transverse grate elements are offset from the transverse grate elements; and at least one longitudinal support beam positioned outward of the intersecting longitudinal and transverse grate elements to provide support for the discharge grate; wherein the discharge grate has more of the at least two spaced apart longitudinal grate elements than the at least one longitudinal support beam.

9. A discharge grate for use in a reducing machine, the discharge grate comprising: at least one longitudinal grate element; a plurality of spaced apart transverse grate elements that intersect the at least one longitudinal grate element to define discharge openings; and at least one longitudinal support beam positioned outward of the intersecting longitudinal and transverse grate elements to provide support for the discharge grate; wherein a plurality of openings extends transversely through the at least one longitudinal support beam between the intersecting longitudinal and transverse grate elements and the at least one longitudinal support beam.

10. A discharge grate in accordance with claim 9 wherein the at least one longitudinal grate element and the plurality of spaced apart transverse grate elements collectively define a curved working surface, and the at least one longitudinal support beam has an arched structure.

11. A discharge grate in accordance with claim 9 wherein the at least one longitudinal grate element and the plurality of spaced apart transverse grate elements collectively define a curved working surface defined by a radius of curvature, each of said at least one longitudinal grate elements and each said at least one longitudinal support beam has an angular orientation relative to a radial direction relative to the radius of curvature, and the angular orientation of each said longitudinal support beam is independent of the angular orientation of each said at least one longitudinal grate element.

12. A material reducing machine, the material reducing machine comprising: a reducing chamber; a material inlet system for feeding material into the reducing chamber; a rotary head having a drive shaft and hammers to reduce the material fed into the reducing chamber; and a discharge grate, the discharge grate including multiple discharge grate components, each of the discharge grate components including: only two spaced apart longitudinal grate elements; a plurality of spaced apart transverse grate elements that intersect the two longitudinal grate elements to form a plurality of discharge openings; and only one longitudinal support beam positioned outward of the intersecting longitudinal and transverse grate elements to provide support for the discharge grate component; wherein the two spaced apart longitudinal grate elements, the plurality of spaced apart transverse grate elements and the longitudinal support beam are fixed together for assembly as a unit into the reducing machine.

13. A material reducing machine in accordance with claim 12 wherein the longitudinal grate elements of at least one of the discharge grate components have an angular orientation relative to a radial direction of the drive shaft that is different than an angular orientation of the longitudinal grate elements of another discharge grate component.

14. A material reducing machine in accordance with claim 12 wherein the discharge grate has a first discharge grate component with a first longitudinal grate element and an adjacent discharge grate component with a second longitudinal grate element, the first longitudinal grate element and second longitudinal grate element each have an outer surface facing away from the drive shaft, and the first longitudinal grate element and the second longitudinal grate element are spaced apart from each other with an angle formed by radial rays extending from the drive shaft to the outer surface of each first and second longitudinal grate element, and the angle between the first and second adjacent longitudinal grate elements is greater than or equal to 8 degrees.

15. A material reducing machine in accordance with claim 12 wherein the discharge grate has a total number of discharge grate components N that includes a first discharge grate component with an outer edge closest to the inlet system and a last discharge grate component rotationally spaced from the first discharge grate component with an opposite outer edge, a radial ray extending from the drive shaft to the outer edge of the first discharge grate component and a radial ray extending from the drive shaft to the opposite outer edge of the last discharge grate component form an angle X, each discharge grate component has a longitudinal grate element with an outer surface generally facing away from the drive shaft, and each of the two spaced apart longitudinal grate element is spaced apart from an adjacent longitudinal grate element with an angle formed by radial rays extending from the drive shaft to the outer surfaces of each adjacent longitudinal grate element, and the angle between the adjacent longitudinal grate elements is about X/N.

16. A material reducing machine in accordance with claim 12 wherein a plurality of openings extends transversely through the one longitudinal support beam of each of the discharge grate components to enable flow-through of material from the discharge openings.

17. A material reducing machine in accordance with claim 12 wherein for each of the discharge grate components, the two spaced apart longitudinal grate elements and the plurality of spaced apart transverse grate elements collectively define a curved working surface, and the one longitudinal support beam has an arched structure.

18. A material reducing machine in accordance with claim 12 wherein for each of the discharge grate components, the two spaced apart longitudinal grate elements and the plurality of spaced apart transverse grate elements collectively define a curved working surface defined by a radius of curvature, each of the two spaced apart longitudinal grate elements and the one longitudinal support beam have an angular orientation relative to a radial direction relative to the radius of curvature, and the angular orientation of the one longitudinal support beam is independent of the angular orientation of the two spaced apart longitudinal grate elements.

19. A material reducing machine in accordance with claim 12 wherein for each of the discharge grate components, each of the plurality of spaced apart transverse grate elements have a support extension that extends beyond an exterior surface of one of the at least two spaced apart longitudinal grate elements and the one longitudinal support beam connects to of each of the support extensions.

20. A material reducing machine, the material reducing machine comprising: a reducing chamber; a material inlet system for feeding material into the reducing chamber; a rotary head having a drive shaft and hammers to reduce the material fed into the reducing chamber; and a discharge grate, the discharge grate including multiple discharge grate components, each of the discharge grate components including: at least one longitudinal grate element; a plurality of spaced apart transverse grate elements that intersect the at least one longitudinal grate element; and at least one longitudinal support beam positioned outward of the intersecting at least one longitudinal grate element and transverse grate elements to provide support for the discharge grate; wherein a plurality of openings extends transversely through the at least one longitudinal support beam between the intersecting longitudinal and transverse grate elements and the at least one longitudinal support beam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is illustrated by way of example and not limited in the accompanying figures, in which like reference numerals indicate the same or similar elements throughout, and in which:

(2) FIGS. 1A through 1K illustrate features of conventional shredding systems and discharge grate components associated with them;

(3) FIGS. 2A through 2I illustrate features of reduction equipment and discharge grate components in accordance with examples of this invention; and

(4) FIGS. 3A and 3B illustrate features of another example discharge grate component in accordance with this invention.

(5) FIG. 4 illustrates features of another example discharge grate component in accordance with this invention.

(6) FIG. 5 illustrates features of another example discharge grate component in accordance with this invention.

(7) The reader is advised that the various parts shown in these drawings are not necessarily drawn to scale.

DETAILED DESCRIPTION

(8) The following description and the accompanying figures disclose example features of reducing equipment structures, discharge grates, and individual components of those grates in accordance with the present invention.

(9) The terms longitudinal, transverse, axial, radial, and the like are used in this specification to describe various angular orientations, directions, and/or features of structures according to the invention. Structures in accordance with this invention may be used in conjunction with a shredder head that rotates around a central axis of rotation. The terms longitudinal and axial as used herein refer to a direction that generally parallels the axis of rotation of the head of the shredding or reducing machine. An element may be straight or curved and still extend in the longitudinal or axial directions. The term transverse as used herein refers to a direction that generally parallels the circular or circumferential direction defined by rotation of the head. An element may be straight or curved around the circumferential direction and still extend the transverse direction. A transverse element need not be oriented at 90 from a longitudinal or axial element at any or all locations, although it may be oriented at a 90 angle at least at some portions. The term radial as used herein refers to a direction generally extending 90 from the axis of rotation of the head.

(10) FIGS. 2A through 2I illustrate various features of discharge grates and individual discharge grate components that form the grates in accordance with examples of this invention. FIG. 2A is a view similar to FIG. 1C showing a discharge grate 214 engaged with a frame member 132 of reducing equipment, and this frame member 132 may have a structure the same as or similar to the frame member 132 shown in FIG. 1C. FIG. 28 provides a bottom perspective view of an individual grate component 230 in accordance with one example of this invention, and FIG. 2C provides a top perspective view of this grate component 230. FIG. 2D provides a top view of the grate component 230; FIG. 2E provides an end or side view of the grate component 230; FIG. 2F provides a front view of the grate component 230; and FIG. 2G provides a sectional view of the grate component 230 taken along line D-D in FIG. 2F. FIGS. 2H and 2I are provided to illustrate various additional features and properties of the individual grate components 230 shown in FIGS. 2A through 2G.

(11) As shown in FIG. 2A, the bottom and side portions of this example discharge grate 214 (e.g., extending approximately 100 to 140 around the circle defined by rotational motion of a shredder head) is made from a plurality of separate discharge grate components 230 aligned around a portion of the circumference of the circle. Five individual discharge grate components 230 are shown in the example of FIG. 2A, although more or less may be used without departing from this invention. The discharge grate 214 also may extend around a greater or lesser portion of the circle. The discharge grate components 230 may include a structure that engages with a corresponding structure provided on a mounting frame 132, e.g., associated with the shredder or other reduction equipment, to enable the discharge grate components 230 to be mounted on the frame 132. If desired, the individual discharge grate components 230 according to the invention may include structures that enable them to be engaged with existing reduction equipment (e.g., existing frames 132 provided on conventional shredding or other reduction mill equipment) so that the discharge grate components 230 of the invention might be used to replace conventional discharge grate components (e.g., 130). The discharge grate components 230 are individually engaged with the mounting frame 132 and slid or otherwise moved along the frame 132 to the desired location in the overall discharge grate structure 214 (e.g., using a crane or other lifting equipment).

(12) FIGS. 2B through 2G show various views of an individual discharge grate component 230. As shown in these figures, this discharge grate component 230 includes two longitudinally oriented grate elements 236a and 236b with a plurality of transverse grate elements 234 extending between the longitudinal grate elements 236a and 236b. Grate discharge openings 214A are defined between the longitudinal grate elements 236a and 236b and the transverse grate elements 234 to provide the sieve or webbing structure to the interior working surface 234S of the grate component 230 (see FIGS. 2C, 2D, and 2G). While generally rectangular shaped discharge openings 214A are shown at the working surface 234S in this illustrated example grate structure 214, other opening sizes and shapes also may be used without departing from this invention, including different discharge opening sizes and shapes within an individual grate component 230 and/or within a single grate 214.

(13) Portions of additional transverse grate elements 234a (called exterior transverse grate elements herein) extend from the outer sides 236c of longitudinal grate elements 236a and 236b. These portions of exterior transverse grate elements 234a cooperate with similar exterior transverse grate elements 234a of adjacent discharge grate components 230 to form grate discharge openings 214A in areas between adjacent discharge grate components 230 when the plurality of grate discharge components 230 are mounted on the mounting frame 132. Although it is not a requirement, the exterior transverse grate elements 234a of this example structure are continuous with (and align with) the transverse grate elements 234 provided between the longitudinal grate elements 236a, 236b.

(14) In this example grate component structure 230, at least some of the transverse grate elements 234 extend outward (away from working surface 2348) to a location beyond the outer surfaces of the longitudinal grate elements 236a and 236b. Note, for example, FIG. 2B. At least some of the outer surfaces of the transverse grate elements 234 include support extensions 250 that extend beyond the outer surfaces of longitudinal grate elements 236a and 236b, and these support extensions 250 form a base for supporting longitudinal support beam 238. The longitudinal support beam 238 may be supported at its ends by one or more of the ends 240 of the grate component 230, one or both of the longitudinal grate elements 236a, 236b, and/or the last transverse grate element 234 at the respective ends. In the illustrated example structure 230, all of the transverse grate elements 234 extend beyond the outer surfaces of longitudinal grate elements 236a, 236b. As a result, the longitudinal grate elements 236a, 236b can extend outward in a direction away from the working surface 234S substantially less than in the prior art, resulting in less weight and the ability for these grate elements 236a, 236b to be oriented at a greater range of angles.

(15) In this illustrated example structure 230, the longitudinal support beam 238 is connected along its longitudinal length to each transverse grate element 234 by support extensions 250 extending outward from the transverse grate elements 234. This is not a requirement.

(16) The longitudinal support beam 238 of this illustrated example includes additional advantageous features. As described above in conjunction with the grate component 130 structure of FIGS. 1C-1K, the longitudinal support beams 138a, 138b of that structure 130 were solid, components (arched or not arched) extending continuously outward from the longitudinal grate elements 136a, 136b. In contrast, the single longitudinal support beam 238 of this example of the invention includes openings 252 defined through it between adjacent transverse grate elements 234. These openings 252 not only lighten the weight of the grate component 230, they provide ample room for discharge of the shredded material through the discharge openings 214A. These openings 252 also provide room for discharged shredded material to fall through the longitudinal support beam 238 so that this longitudinal support beam 238 is less likely to act as a shelf on which discharged shredded material hangs up, even at the upper side area S of the overall discharge grate 214 (see FIG. 2A). The openings 252 also provide locations at which a crane or other lifting equipment can engage the grate component 230, e.g., for installation to the frame 132, for removal, for transport and/or other handling, etc. Other lift supports also could be provided on the grate component structure 230 (including on the beam 238), if desired. The provision of openings in the support beam is beneficial for improving the flow of the discharge material out of the reducing chamber of the machine and reducing weight of the discharge grate component even in grate components provided with two support beams and even when the support beams are formed as extensions of the longitudinal grate elements.

(17) Notably, this example grate component structure 230 in accordance with the invention includes a single longitudinal support beam 238 (as opposed to the two beams 138a and 138b shown in the example construction of FIGS. 1C-1K). This single longitudinal support beam 238 provides sufficient support for a grate component structure 230 that includes two longitudinal grate elements 236a, 236b. The elimination of one longitudinal support beam in the grate component structure 230 according to this example of the invention (as compared to the structure of FIGS. 1C-1K) provides significant weight, raw material, and cost savings. It also results in less scrap material when the grate components 230 are worn and taken out of service, as will be described in more detail below. The use of a single longitudinal support beam 238 also halves the number of longitudinal support beams in the overall grate structure 214 (as compared to the example construction of FIGS. 1C-1K), which also provides a more open arrangement to allow better release of shredded material through the grate structure 214 (e.g., fewer extending longitudinal support beams and less beam surface area to interfere with discharged material flow, larger gaps between longitudinal support beams 238, etc.). The discharged material is more likely to get hung up in the more closely located longitudinal beam components 138a, 138b of the example structure of FIGS. 1C-1K as compared to the more spaced apart longitudinal beam components 238 of FIGS. 2A-2I.

(18) In some examples of this invention, the grate components 230 in an overall grate 214 may all have the same structure, including the same discharge angles. This is not a requirement. Because the longitudinal support beams 238 of grate component structures 230 in accordance with this example of the invention do not extend continuously from the longitudinal grate elements 236a, 236b, these grate components 230 may be constructed such that the angular orientation of longitudinal support beam 238 is independent of the angular orientation of longitudinal grate elements 236a, 236b (the angular orientations may be measured with respect to a radial direction from the drive shaft of the hammer and/or with respect to a direction perpendicular to the working face 234S of the grate component 230). Therefore, the grate component structures 230 around a single grate structure 214 may be designed to have different angular orientations for the longitudinal grate elements 236a, 236b (and thus different angular orientations for the discharge openings 214A), if desired. This feature can allow the angular orientations for the longitudinal grate elements 236a, 236b and/or the discharge openings 214A to be optimized for specific locations around the overall grate structure 214 (e.g., the angular orientation of the longitudinal grate elements 236a, 236b and/or discharge opening 214A of the grate component 230 nearest to the anvil 108 may be different from the angular orientations of the longitudinal grate elements 236a, 236b and/or discharge openings 214A of the grate components 230 located downstream in the hammer rotational direction). This can help optimize discharge of shredded material through the grate 214. As still other examples, if desired, two or more grate components in a grate structure may have a first structure (e.g., with one discharge angle) while other grate components in the same grate structure may have one or more different structures (e.g., different discharge angles). Discharge grates in accordance with some examples of this invention may include one or more individual grate components 230 in accordance with aspects of the present invention combined with one or more conventional grate components.

(19) In some examples of this invention, the longitudinal support beam 238 will extend outward in a direction substantially parallel to or substantially aligned with the radial direction from the drive shaft of the hammer and/or in a direction substantially perpendicular to a working face 234S of the grate component 230 at the location of the longitudinal support beam 238 (prior to wear of the working face 234S). Note, for example FIG. 2H.

(20) This orientation and/or arrangement of the longitudinal support beam 238 with respect to the working face 234S of the grate component 230 is advantageous for other reasons as well. For example, as shown in FIG. 2H, when arranged in this manner, the direction of greatest strength of the grate component 230 (extending straight through the longitudinal support beam 238, down the center of the longitudinal support beam 238, as shown by arrow 254 in FIG. 2H) is substantially aligned with (and optionally directly aligned with) the direction of impact force on the working surface 234S from rotation of the hammers (shown by arrow 256 in FIG. 2H) and/or a direction normal to the working surface 234S at that location. By at least substantially aligning the directions 254 and 256, deformation, deflection, bending, and/or the likelihood of breaking the grate component 230 can be reduced (or eliminated). Additionally or alternatively, this feature also allows the longitudinal support beam 238 to provide adequate support for use while still allowing a manufacturer to reduce the overall weight of the grate component 230 (e.g., by including the openings 252 in the longitudinal support beam structure 238). This orientation and arrangement of the longitudinal support beam 238 provides the support material at locations and orientations where it will be most effective to provide adequate support and stiffness, and it accomplishes these objectives using a reduced amount of material in the structure (and thus at a reduced weight), as compared to the conventional structures described above. Reduced grate deflection also allows more of the impact energy of the hammers to be transferred to the material being processed (rather than being expended on deflecting the grate component 230).

(21) As shown in FIG. 2E, in this illustrated example, the longitudinal support beam 238 is arranged so that its centerline C/L extends substantially parallel to a centerline C/L of the two ends 240 of the grate component 230. While it is not a requirement, the longitudinal support beam 238, the ends 240, and/or the transverse grate elements 234 may be symmetric on opposite sides of a plane extending into and out of the page of FIG. 2E along the centerline C/L. Other arrangements, however, in which the centerline of the support beam 238 does not align with the centerline of the ends 240 and/or in which one or more of the various components are not symmetrically shaped in the manner described above are possible without departing from this invention.

(22) As shown in FIG. 2A, grate structures 214 in accordance with examples of this invention may include multiple grate components 230, e.g., of the types described above in conjunction with FIGS. 2B-2G. In such grate structures 214, the angular separation or spacing between adjacent longitudinal support beams 238 of adjacent discharge grate components 230 (e.g., as measured from radial rays extending from the drive shaft axis of the rotor to corresponding locations on the outer surfaces of two adjacent longitudinal support beams 238) may be about X/N, wherein X is the number of degrees from: (a) an outer edge 240A of one grate component 230 in the grate structure 214 (e.g., the grate component 230 nearest to the anvil and/or the first grate component 230 in the grate 214 with respect to a hammer swing direction) to (b) an opposite outer edge 240B of another grate component 230 (e.g., the grate component 230 at the opposite end of the grate structure 214 and/or the last grate component 230 in the grate 214 with respect to a hammer swing direction); and N is the number of individual grate components 230 located between these outer edges 240A, 240B (e.g., a total number of grate components 230 in the grate structure 214). In the example structure illustrated in FIG. 2A, for the entire grate structure 214 the angle X is about 120, the number N is 5, and the separation angle of adjacent longitudinal support beams 238 is about 120/5, or about 24. While the angular orientation measurements can be made at any corresponding locations on two adjacent longitudinal support beams 238, in some examples of this invention, the radial rays from the drive shaft axis A of the rotor will extend to points on the centerline C/L of the longitudinal support beams 238. As also shown in this example, the number of longitudinal support beams may have a 1:1 relationship with the number of grate components 230 in the overall grate structure 214 (or within an X range of the overall grate structure 214).

(23) As other examples, grate structures 214 in accordance with this invention that include multiple grate components 230 may include multiple grate components 230 that are sized and oriented such that the angular separation between adjacent longitudinal support beams 238 of adjacent discharge grate components 230 (e.g., as measured from the drive shaft axis of the rotor) are greater than or equal to 8. In one preferred embodiment, the angular separation between adjacent longitudinal support beams 238 of adjacent discharge grate components 230 are within a range of 8 to 36, and in some examples, within a range from 8 to 30.

(24) As described above, some aspects of this invention relate to providing a reduction mill grate assembly 214 that may be installed in existing reduction mills and provide a support structure (and an individual grate component structure 230) with a lower mass. A lower mass for the grate assembly 214 will correspond to a lower cost grate component 230 that is more easily handled (e.g., for installation on frame 132) and that results in less scrap material when the grate components 230 are replaced. FIG. 2I illustrates portions of a grate component 230 in accordance with this example of the invention that may be scrapped when the useful life of the grate component 230 has ended (e.g., the top portion of the grate component 230 shown in FIG. 2H may have been largely ablated and worn away after significant use). As evident from a comparison of FIG. 2I with the similar view of FIG. 1K, aspects of this invention can result in a significant reduction of scrapped material (e.g., due to the presence of a single longitudinal support beam 238 and/or the presence of multiple openings 252 through this longitudinal support beam 238 as compared to the known grate component structure 130).

(25) As a more concrete example of this potential weight and material savings, for a 74 inch (188 cm) shredder using four grate components 130, 230 to form a grate structure 114, 214 (made from the Hadfield Manganese Steel material described above), a grate component 230 having the structure of FIGS. 2A-2I will weigh about 265 lbs less than the corresponding grate component 130 of FIGS. 1C-1K (for a total weight savings of about 1060 lbs for the four grate components in the overall grate structure). This represents a weight savings of about 7%.

(26) While described above as including various areas, regions, portions, or the like, those skilled in this art will recognize that grate components 230 in accordance with this invention may be made as one or more parts. In some more specific examples of this invention, the grate components 230 will constitute a single piece of material that is cast into the desired shape as described above and as illustrated in FIGS. 2A-2I. The grate components 230 may be made by methods as are conventionally known and used in this art (e.g., conventional casting and/or hardening methods). The grate components 230 also may be installed on reduction machines in manners that are conventionally known and used in this art.

(27) The grate component 230 design and construction of at least some examples of the present invention at least somewhat separates the longitudinal grate elements 236a, 236b from the support (deflection and bend resistance) function of the longitudinal support beam 238 to better support the grate component 230 against the impact forces imparted by the hammers. The longitudinal support beam 238 resists deflection and bending, and the longitudinal grate elements 236a, 236b can be configured to resist wear at the impact face 234S and/or to provide the desired discharge angle for the shredded materials. Reduced deflection and bending results in less grate-to-grate interference and allows grate end supports 240 to function as designed (e.g., better allows the grate components 230 to slide on the frame rails or other structures, even after use). The single longitudinal support beam 238 alters the ratio of mass distribution between the impact face 234S and the support structure so that a larger percentage of the grate's mass is in the usable wear area where it will be most effective while providing the same stiffness. Lower installation weight, reduced throw-away weight, and equivalent performance to existing product significantly reduce operating costs for the capital machinery. Also, because the design of the beam 238 also centers the direction of greatest strength of the beam 238 so that it is substantially in line with the force of the hammer impacts (FIG. 2H), the tendency of the beam 238 to warp tangentially and/or bend transversely is reduced so maintenance (e.g., grate replacement) can be performed efficiently with minimal downtime of the equipment (e.g., less need to cut out grate components 230 that interfere with adjacent grate components 230 and/or that cannot be moved along the tracks of frame 132).

(28) Because the longitudinal support beam 238 provides the primary structural support in countering bending and deflection of the grate component 230, the longitudinal grate elements 236a, 236b may be made somewhat smaller in cross section than the conventional longitudinal grate elements 136a, 136b that extend continuously into support beams 138a, 138b. Thus, if desired, the mass and amount of material used to make the longitudinal grate elements 136a, 136b may be reduced. This factor also can contribute to the reduction in mass of the grate components 230, the reduction in the amount of scrapped material at the end of the grate component's service life, and the ability to orient the longitudinal grate elements at a greater range of angles.

(29) As noted above, in the example structure shown in FIGS. 2A-2I, the exterior transverse grate elements 234a are continuous with (and align with) the transverse grate elements 234 provided between the longitudinal grate elements 236a, 236b. This is not a requirement. For example, FIGS. 3A and 3B show an example grate component 330 in accordance with one example of this invention in which the transverse grate elements 334 (located between longitudinal grate elements 336a, 336b) are offset with respect to the exterior transverse grate elements 334a. In this manner, each longitudinal row of discharge openings 314A may be staggered or offset from adjacent longitudinal rows of discharge openings (e.g., the discharge openings formed between adjacent grate components 330 in an overall grate structure). This staggered arrangement of discharge openings provides more paths along which reduced scrap material can be pushed through the grate component 330.

(30) When staggered, it is not required that each longitudinal row of discharge openings 314 be offset with respect to each adjacent row. Any desired pattern of staggered rows and unstaggered rows may be provided in an overall grate structure without departing from this invention. Also, it is not required that adjacent rows be staggered such that the centers of the discharge openings 314A of one longitudinal row of openings 314A are located halfway between the centers of the discharge openings 314A of the adjacent longitudinal rows of openings. Rather, any desired amount of longitudinal offset or stagger may be provided between adjacent rows.

(31) As noted above, in the example structure shown in FIGS. 2A-2I, the longitudinal support beam 238 is connected along its longitudinal length to each transverse grate element 234 by support extensions 250 extending outward from the transverse grate elements 234. This is not a requirement. For example, in one alternative embodiment shown in FIG. 4, a grate 430 similar to grate 230 is provided with a longitudinal support beam 438 that is connected along its longitudinal length to transverse grate elements 434 by support extensions 450 extending outward from the transverse grate elements 434. However, unlike grate 230 shown in FIGS. 2A-2I, the longitudinal support beam 438 is not connected to the last transverse grate element 434 on each end of the grate 440. Instead, longitudinal support beam 438 is connected to support extensions 451 adjacent ends 440 and extending outward from the longitudinal grate elements 436a and 436b. This allows the grate openings 414A adjacent ends 440 of grate 430 to be further opened up for material discharge. Other arrangements may include, for example, support extensions connecting every other transverse grate element with the longitudinal support beam, support extensions connecting two of every three transverse grate elements with the longitudinal support beams, etc.

(32) In the example structure shown in FIGS. 2A-2I, the longitudinal support beam 238 is connected to each end lug or the last transverse grate element 234 with a support extension 250 at the respective ends 240. The last support extensions 250 adjacent the ends 240 of grate 230 are shown as partially extending over discharge openings 214A. In addition support extensions 250 are shown as generally having the same width as transverse grate elements 234. It is not a requirement for the support extension to have the same width as transverse grate elements 234 or for the last support extensions 250 to partially extend over discharge openings 214A. In some cases it may be desirable to alter the shape of support extensions 250, to have the support extensions generally wider than transverse grate elements 234, or to have the support extensions generally thinner than transverse grate elements 234. For example, in one alternative embodiment shown in FIG. 5 grate 530 is provided with a longitudinal support beam 538 that is connected along its longitudinal length to transverse grate elements 534 by support extensions 550 extending outward from the transverse grate elements 534. The support extensions 550 extending from the last transverse grate elements 534 at the ends 540 of grate 530 are thinner than transverse grate elements 534. In addition, each support extension 550 has a base connected to the transverse grate elements that is substantially clear of discharge openings 514A to allow the material to flow more easily through the grate. As previously stated, while grate 530 is shown with only two support extensions 550 that are thinner than the transverse grate elements 534 it is also possible for additional support extensions 550 to be generally thinner than the transverse grate elements 534.

(33) Although preferred embodiments are described above, other arrangements are possible for grates and grate components in accordance with the invention. Different aspects of the invention can be used in isolation to achieve some of the benefits of the invention. A variety of different configurations could be used to form the grate openings 214A, the end supports 240, the longitudinal support beam 238, the grate elements 236a, 236b, 234, and other disclosed features. Any combination of described features that performs at least some portion of the disclosed functions and/or provides at least some portion of the disclosed advantages falls within the scope of this specification. While a grate component with a single beam and two longitudinal grate elements (a so-called double grate component) is preferred, aspects of the invention are usable with grate components provided with a single beam and a single longitudinal grate element (a so-called single grate component), or double grate components with two support beams and two longitudinal grate elements. Further, the invention encompasses other arrangements of a discharge grate component where there are less support beams than longitudinal grate elements, such as a grate component with one or two support beams and three longitudinal grate elements.

CONCLUSION

(34) The present invention is described above and in the accompanying drawings with reference to a variety of example structures, features, elements, and combinations of structures, features, and elements. The purpose served by the disclosure, however, is to provide examples of the various features and concepts related to the invention, not to limit the scope of the invention. One skilled in the relevant art will recognize that numerous variations and modifications may be made to the example structures described above without departing from the scope of the present invention.