US3235188A - Reduction mill - Google Patents

Description

Feb. 15, 1966 R. R. BRADLEY 3,235,188 i REDUCTION MILL Filed March 8, 1.963 2 Sheets-Sheet 1 R. R. BRADLEY REDUCTION MILL Feb. 15, 1966 2 Sheets-Sheet 2 Filed March 8, 1963 WMM v INVENTOR RALPH R. BRADLEY United States Patent Oiice 31,235J83 Patented Feb. 15, 1955 3,235,1sa REDUCTIN MILL Ralph R. Bradley, 1102 N. Tuxedo, Indianapolis, Ind. Filed Mar. 8, 1963, Ser. No. 263,892 ll Claim. (Cl. 21M-'74) This invention relates generally to ore reduction and more particularly to a machine for mechanically disintegrating ores or other raw materials for subsequent recovery of valuable constituents therein.

Many configurations of machines have been devised for mechanical reduction of ores. The disadvantages of the machines heretofore devised include utility limited to certain types or sizes of ores, excessive contact of sufficiently reduced ore with an impact or beating member, inadequate opportunity for the reduced ore materials to leave the reduction machine, and difficulty of maintenance.

It is therefore, a general object of the present invention to provide improved means for reduction of ores and other raw materials.

A further object is to provide a reduction mill capable of handling a wide variety of types and grades of ore and raw material with maximum possible efficiency.

A further object is to provide a mill which does not work the material excessively.

A further object is to provide a reduction mill of durable construction and which is easily maintained.

`It is a further object to produce a machine which will reduce the material being processed to a predetermined size and wash it through a perforated metal classifier as quickly as possible and thereby prevent unnecessary recycling ofthe material.

The full nature of the invention will be understood from the accompanying drawings and the following description and claim.

FIG. l is a front elevational view of a typical embodiment of the present invention.

FlG. 2 is an end elevation thereof.

FlG. 3 is an enlarged fragmentary end elevation with portions broken away to illustrate interior details.

FIG. 4 is a fragmentary section taken along the line 4-4 of FIG. 3 and viewed in the direction of the arrows,

FlG. 5 is an enlarged bottom view of a feed tube employed in the illustrated embodiment.

FIG. 6 is an enlarged fragmentary section taken along the line 6-6 in FIG.

FIG. 7 is an enlarged fragmentary section taken along the line 7--7 in FIG. 4.

Referring to the drawings in detail, the illustrated ein bodiment includes a base ll with upstanding end frames l2 and 13 mounted thereto. Each end frame includes a pair of spaced uprights ftd and lo with a horizontal member f7 connected between the upper ends of the uprights. An intermediate horizontal member lll is connected between the uprights. Grooved support rollers 19 and 2. are mounted for rotation on the pillow blocks 22 which are secured to the cross member i8.

A drum 2d is provided with support rings Z6 and 27 at opposite ends thereof, and these rings are supported by the grooved rollers mounted to the end frames. inasmuch as the support rings are circular, and both are centered on an axis Z8, the drum is thereby able to rotate about the axis 28. Each of the support rings is formed of two parts. For example, support ring 27 has a first half 27a and a second half 2%.

rEhe shaft 29 may be keyed or splined to the roller i9 and has a sprocket 3l adjacent its outer end. An additional shaft or mandrel 32 is mounted for rotation in the pillow blocks 33 and 3d mounted on the upper crossmembers 17 of the end frames. This mandrel also has a pulley 36 keyed or splined thereto.

The motor 37 carries a sheave 37a which is belted to the input sheave of a reduction drive 38. The output of the reduction drive 3S drives the counterpart of the shaft 2f@ and hence the roller 2l. Outboard of the frame member 17, the right hand counterpart (as viewed in FIG. 2) of shaft 29, carries a sprocket similar to sprocket 3l and these are joined by chain 31a so that rollers 19 and Z1 are driven by motor 37. The motor sheave 37a is also belted to sheave 36, the drum 24 being thus rorated about its axis 2S. The sizes of the parts are selected so that the typical average rotational speed of the drum is 7 rpm. while the rotation of the shaft 32 is 707 rpm. Both the drum and the shaft are driven in the same rotational direction.

At each end of the drum there are two identical end plates fastened together and, with the drum in the position shown, these may be designated as the upper end plate al4a and lower end plate 44h. inasmuch as there are two of these plates at each end of the drum and they are identical, only one will be described in detail.

Referring to the end plate 44a, it has a circular outer surface 46 and a concentric circular inner surface 47. rhe outer and inner faces 4S and 49 are in parallel planes. The end faces or edges 5l and 52 are parallel but do not lie in the same plane. A flat keying plate 53 is welded to the external surface 4S of the end plate and has a key slot 5d therein. A key 56 is welded to the surface 43 adjacent the other end 5l of the end plate ls/itz.

The upper and lower end plates are assembled together as shown in FIG. 3 whereupon the keying plate 53 is secured to the end plate 44h by means of the two screws 57. The key 56h welded to the end plate Mtb is received snugly in the key slot 54 of the keying plate 53. The two end plates are secured in like manner by the screws 57h, keying plate 53h, and key 56. The offset arrangement of the edges 5l and 52 of the end plates contributes to rigidity of the entire unit. The upper drive ring 27a is secured to the upper end plate by the screws 53o and the lower drive ring 271') is likewise secured to the lower end plate ddh by means of the screws 53h.

At each end of the drum, four identical quadrant plates 59 are secured to the end plates. At the end shown in FIG. 3, the quadrant plates are identified 59a and 59h, 59C and 59d. Because all of these quadrant plates, are identical, plate 59a will be described in some detail and this description applies equally well to the remaining quadrant plates.

Plate 59a has an outer circular surface @la and an inner concentric circular surface 62a. The plate has an outer planar surface 63a and an inner surface 64a parallel to the outer surface.

The front edge 66a lies in a vertical plane slightly olfset from a vertical plane through the axis 23. It has an integral lug 67a extending therefrom whose outer circular surface is a continuation of the surface ola.

The rear edge 68a lies in a plane para lel to the edge 52 of the end plate, both of which edges are horizontal with the drum positioned as shown. This edge has a lug @a extending therefrom below a horizontal plane through the axis 23 and located somewhat radially inwardly from the outer circular surface 61a.

By this construction, the lug 67a, of quadrant plate 59a and the lug 69d of the quadrant plate 59d overlap as shown. Likewise the lug 67h of the quadrant plate 5911 overlaps the lug 69a of the quadrant plate 5522i. The same type of overlying relationship is provided at the junctions of the quadrant plate S with the quadrant plates 59!) and 59a'.

Each of the quadrant plates is bolted to one of the end essaies plates. For example, the qudrant plate 59a is bolted to the upper end plate 44a by means of the bolts 71a. The quadrant plate is bolted to the lower segment or end plate 44h by means of the bolts '7111.

The pair of end plates at one end of the cylinder or drum is held in parallel horizontally spaced relationship to the pair of end plates at the opposite end of the cylinder by four tie bars. Three of these are shown in the drawings and .are designated by the reference numerals 72, 73, and 74. Each of the tie bars is secured to the end plates by means of two screws 76 at each end of the bar. The end portion of each tie bar is disposed in the space between the end portions of the adjacent quadrant plates. For example, tie bar '72 is disposed in the horizontal space between the end portions 66a and 65d of the quadrant plates 59a and 59d respectively. Of course, it should be understood that in normal assembly of the drum, the quadrant plates :are installed after the assembly of the end plates and tie bars. This, in fact, assists in the location of the quadrant plates as they are secured to the end plates by the bolts 71a, 71h, 71d, and 71C (not shown).

Two stiflening bars 77 `and 73 are secured to eac-h of the four tie bars by the screws 79 (HSS. 4 and 6). These stitening bars serve additional function of providing mounts for four quadrant strips located intermediate the ends of the cylinder. Three of these quadrant strips are shown in the drawing and are designated by reference numerals 81, 82, and 83 (FGS. 4 and 7). A lug 84. is welded to the inner circular surface 36 of each of these strips adjacent its front end 87. rThis provides a boss to receive two mounting screws 83 by which the front end portion ot the quadrant strip is secured to the stiffening rib 77. At the rear end 39 of each of the quadrant strips, an abutting engagement with the stiffening bar 7S is provided and two screws 91 secure the quadrant strip to the stidening bar 78. These quadrant strips provide support for the classifying screens which will be described hereinafter.

To provide classifying screens, eight sheets of perforated metal are mounted to the drum structure heretofore described. Inasmuch as each of the eight s-heets is identical to the rest, only one will be described and this one is designated by the reference numeral 92. Sheet 92 is curved so as to form a portion of the cylinder or drum 24. It is secured in place by the quadrant bands 93 and 94. The band E3 is secured to the quadrant strip 81 by means of screws 96. The band 9d is secured to the quadrant plate 59C in like manner by the screws 97. The remaining seven sheets are identical to the sheets 92 and are mounted in the same manner.

Baiiie plates 98 are provided in the cylinder in a circular array. Each of the plates has a pair of tabs 99 at each end thereof which tabs are secured by the screws 161 to quadrant plates. Each of four of the battle plates is disoosed immediatel adjacent one of the sets of tie bars 73 and reintorcing or stifening bars '77 and 73. These bars therefore cooperate with the baille plates and quadrant plates to form four pockets in the drum. When the drum is rotated in the direction of the arrow 162, these pockets can collect material deposited `on the screen adjacent to the baille, elevate the material, and dump it as the pocket reaches and passes its uppermost point of travel during rotation of the drum. The other battle plates may be provided with adapter strips 163 which are conveniently made of angle irons with an edge 1414 touching the innerl cylindrical surface of the screens. These strips 103 are bolted to the battle plates and can be removed if desired.

The mandrel 32 has previously been mentioned. This mandrel has a disc 166 mounted at approximately the longitudinal center of the mandrel portion between the pillow blocks 33. This disc is welded or otherwise secured to the m-andrel 32;. Stabiiizing rings 1W! are provided adjacent the quadrant plates of the cylinder and are coaxial with shaft 32. These stabilizer rings are open at the center to provide a central opening with a cylindrical wall 168 in each. The stabilizer rings are otherwise practically identical to the disc 106.

The disc 106 and stabilizing rings 199 are formed to provide a plurality of receiving notches therein having a straight edge 109 tangential with a circle concentric with the axis 2S. Each notch has an edge 111 at right angles to edge 199. An elongate blade support bar 112. is mounted to each of the two stabilizer rings and the drive disc by suitable means such as the bolt 113 for example. To each of these blade support bars is mounted a plurality of hardened steel blades 111i which may be secured thereto by suitable means such as the bolts 116, for example. There is thereby formed a squirrel cage type of rotor with a plurality of impact plates or blades disposed thereon in parallel relationship. In the illustrated example there are six sets of such blades. As previously mentioned, this rotor normally rotates at a speed of approximately 707 r.p.m. while the cylinder is rotated in the same direction at a speed of approximately '7 rpm.

Referring specilically to FIGS. 2 and 4, means are shown for covering the ends of the drum. At each end an upper end cover plate 117 is mounted by means of the brackets 113 to each of the end plates. The lower edge 119 of this plate is horizontal and is level with the axis 28. Rings 121a and 12117 are secured to the inner faces of the end plate 44a and ftd-b respectively. These rings overlap the marginal inner face of the cover plate 117 as the drum rotates. This prevents loss of material from the inside of the cylinder around the edge of the upper cover end plate.

A lower cover plate 122 is mounted by means of the brackets 123 to the end frame at each end of the cylinder. The upper edge 1241 of this plate engages the lower edge of the upper end end cover plate to prevent material from getting out of the cylinder at this point. A circular ring member 126 is welded to the inner face of the lower end cover plate 122 and has a mitered edge 127 extending over the ring 121 secured to the end plates and prevents loss of material from the inside of the cylinder to the exterior at this point.

A feed tube 131 is mounted to the upper end cover plate at each end of the cylinder. This feed tube is normally stationary. Its inner end 133 projects well into the center of the rotor and adjacent the disc 166. As shown in FIG. 5, each of the feed tubes has a V-shaped discharge notch 134 therein. This notch begins at a point near the plane of the inside face of the stabilizer ring 198 and diverges to the inner end 133 of `the tube. Raw =materials from any suitable source are supplied through this tube to the interior of the rotor.

Referring further to PEG. 2 as well as FIG. l, a horizontal cross-member 136 is mounted to the end frames and extends above the drum. Nozzles 137 may be mounted to this crossmember to discharge water or other fluids through the classifying screens into the inside of the drum. A trough 138 is disposed below the cylinder and may iuclude a conveyor or other means to receive the reduced raw material which passes through the screens from the inside of the cylinder at the bottom of the cylinder.

In operation, the cylinder and rotor are driven and the usual speeds are mentioned above. Raw material is fed into the rotor through the feed tubes. It falls from the feed tubes and is struck by the whirling rotor blades. It is partially disintegrated thereby and portions are thrown against tbe baiiies for further disintegration. The attitude of the bale plates protects the screens from direct impact of material thrown by the blades.

Partially or wholly disintegrated material falls to the screens at the bottom of the drum and most of that of the proper size will pass through and into trough 133. That which does not pass through is carried up by the pockets and dumped through the rotor for further reduction. During the process, Water may be applied if desired.

Various properties peculiar to each particular type of ore or rock to be processed will cause a variation in the number of cycles the material must make through the irnpact blades before it has been reduced to the proper size.

Materials that shatter more readily will pass through the classifier perforations quicker -if allowed to roll or wash over a larger surface of classifying screens. This type of material would require fewer pickup pockets and eliminate excessive wear of the impact blades.

In the present invention, the open end baille plates with adapters make it possible to convert each baille into a pickup pocket to recycle the material through the impact blades for further pulverization, or conversely to reduce the number of pickup pockets if so desired.

The versatility of this feature will result in a more efilcient and economical operation Ias it can be adjusted to the particular type of material being processed.

From the foregoing description, several important 'additional advantages of the present invention can be readily understood. The classifying screens can be removed individually and quite easily and permit access to the baf- Iile plates. Baille plates or baille plate adapters 103 can thereby be readily removed in the event that less ballling or pocketing action of the material treated by the machine is required. This allows more travel of the material over the screen yas the cylinder rotates and by providing a greater Ieffective screen area permits the properly reduced raw materials -to be discharged during a greater portion of cylinder travel. The reduced materials are thereby discharged at a greater rate than would otherwise be possible. This is a distinct advantage over types of equipment having limited screening distances. It eliminates the need for recirculation and eliminates unnecessary handling and undue working of raw material which would otherwise occur if material reduced to the proper size were continuously carried up by the pockets and dropped through the rotor.

If it is ever desired, an entire quadrant of the cylinder can be readily removed `therefrom while the remaining three quadrants remain in place. Moreover, the remaining three quadrants can be removed leaving only the end plates and drive ring 4and tie bars. It can be seen therefore, that this machine lends itself to quick disassembly 'and for this reason can be moved from place to place readily. This is a substantial advantage where it is desirable to refine raw materials at or near `a source of origin.

4By the use of the tapered slot and by extending the feeding tubes well into the center of the rotor, it is possible to discharge heavy or large particles toward the center of the rotor where they will have ample exposure to impact on the impact blades and will be thrown against the bailles. The smaller particles are discharged nearer the stabilizing end rings of the rotor. Therefore, distribution of raw materials across the rotor is fairly uniform, tending to promote equalized leading across the impact chamber and uniform wear of the blades.

Nevertheless, where lthe materials are of a smaller size such as coarse grained sand or tailings from old mill ponds and the like, they can be fed into the impact chamber through a non-graduating `slotted feed tube inter- -changeable with those illustrated, allowing even distribution of material across the impact blades.

The heavy construction of the disc 106 and the stabilizing rings 108 provides a flywheel effect whereby even the heaviest of materials can be handled smoothly.

yFrom the foregoing description, it will be appreciated that the present invention lends itself to the most efficient type of loperation possible with the material being handled. Also, -in addition to efficiently reducing the raw material, the machine will last a long time and require a minimum of maintenance. Whenever maintenance is required it can be `accomplished readily. Moreover, if it is desired to move the machine from place to place, this can be accomplished readily.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be lconsidered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and Within the broad `scope of the invention, reference being had to the appended claim.

The invention claimed is:

A reduction mill comprising:

a frame, :a drum mounted for rotation on said frame, means driving said drum in one rotational direction on said frame, a plurality of llat baille plates disposed in said drum and extending from one end of said drum to the other end thereof and .secured to said drum at their ends, said plates being spaced around the axis of rotation of said drum and located radially outward therefrom, said drum having -a classifying screen with an inner Wall surface extending around said axis at a substantially constant distance from said axis, said baille plates having their outer marginal yedges spaced radially inward from said wall surface to permit passage of raw materials in `said drum along said wall surface between said surface and said edges during rotation of said drum, -said baille -plates being inclined with respect to intercepting radi-i from said axis, adapter members Ibolted to certain of said baille plates and extending outwardly therefrom to said wall surface and cooperating with said certain baille plates to form pockets in said drum, said pockets `pocketing said raw materials and carrying them up in a circular path during drum rotation in said one direction, said adapter members being removable from selected ones of said certain baille plates to disable the pocketing by said selected plates and extend the circumferential distance on said' surface between pockets thereby permitting said passage of said raw materials past said selected ones of sa-id certain baille plates during rotation of said drum and providing a greater effective screen larea discharging materials from said drum during rotation.

References Cited by the Examiner UNITED STATES PATENTS 1,744,028 1/1930 Borton 241--87 X 1,948,504 2/1934 Borton 241-85 X 2,199,729 5/1940 Peterson 241-85 X 2,524,482 2/1951 Cully `241---87 X 2,837,289 l6/1958 Heckett 241--91 `2,837,290 6/1958 Nagel 241-186 2,950,870 8/1960 'Danyluke 241--91 3,079,095 2/ 1963 Beards 241-85 ROBE-RT C. RIORDON, Primary Examiner.

J. SPENCER OVERHOLSER, Examiner.

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