US1763165A - Apparatus for breaking coal - Google Patents

Description

June 10, 1930. w. K. LIGGETT 1,763,165

APPARATUS FOR BREAKING COAL Filed Dec. 4, 1925 2 Sheets-Sheet 1 h "'J Hfi'IO, 1930. w. K. LIGGETT APPARATUS FOR BREAKING COAL Filed Dec. 1925 2 Sheets-Sheet 2 III/IIIIIIIIIIIIIII mm; W

with slack.

Patented June 10, 1930 UNITED STATES PATENT OFFICE WILLIAM K. LIGGETT, OF COLUMBUS, OHIO, ASSIGNOR TO THE JEFFREY MANUFAC- TURING COMPANY, OF COLUMBUS, OHIO, A CORPORATION OF OHIO APPARATUS FOR BREAKING GOAL Application filed December 4, 1923.

This invention relates to new and useful methods of and apparatus for reducing material from relatively large to smaller pieces.

As an illustrative example, I shall herein describe my improved method and apparatus in connection with the reduction of run of mine coal, so called for the reason that as the coal comes from the mine, it is made up of relatively large lumps of di'lferent'sizes mixed In reducing this material for use in mechanical stoker grates, it is desirable to bring it to a uniform and predetermined size without undue pulverization, it being desirable to avoid, so far as possible, increasing the amount of slack.

It will be understood that this disclosure is simply illustrative and in no sense restrictive of my invention, which is adapted to the reduction of material other than that herein specifically disclosed.

The means by which I attain this object are fully set forth in the following specification, and illustrated in the accompanying drawings, which show one physical embodiment of my invention, and in which Fig. 1 is a side elevation of a machine embodying my invention.

Fig. 2 is a sectional view taken on substantially the line IIII of Fig. 1.

Fig. 8 is a transverse sectional view taken on substantially the line IIIIII of Fig. 2.

Fig. 4 is a fragmentary sectional view taken on substantially the line IVIV of Fig. 3.

Referring to the drawings by numerals, like numbers indicating like parts in the several figures, it will be seen that, as here shown, my improved machine consists of a reducing element which may, of course, take various forms, but in this illustration of the invention, is in the form of a skeleton rotor adapted to revolve within a casing, it beingshown in the present instance as revolvingabout a horizontal axis, which casing is adapted to confine the material. The casing comprises the main supporting frame 1 and the housing 2 which are joined together, as here shown, along the horizontal central plane of the rotor, although variations of this arrangement may be made. The main frame 1 has the end walls 3 and the side walls 4, prefer- Serial No. 678,456.

ably, though not necessarily, formed of a single casting. These walls may be provided along their lower edges with flanges 5 adapted to rest upon and be attached to any suitable foundations, and their upper edges are flanged, as at 6, to permit the housing 2 to be bolted thereto.

At the ends of the main frame 1 are journal bearings 7 which may be of any suitable type, and are designed to support the rotary element of the machine. J ournaled in the bearings 7, and in the embodiment of the invention herein disclosed projecting at both ends beyond said bearings, is a shaft 8, to one end of which is attached a pulley 9 by which the rotor may be connected through a suitable belt with any convenient source of power.

Obviously drive mechanisms of other types may be used, if desired.

Mounted upon the shaft 8, and here shown in spaced relation to one another, are a plurality of discs 10 which are secured to the shaft 8 in any preferred manner, as by the key 11, to revolve therewith. Disposed longitudinally of the shaft 8 and supported in suitable apertures of the discs 10 are a plurality of rods 12 upon which arms designed to engage and reduce the material are supported. The arms are preferably formed of castings of a refractory alloy of iron, fashioned to provide three radial projections 13, 14 and 15, preferably equally spaced and extending from a common center, each of said arms being pierced by an aperture 16 adapted to receive one of the rods 12. lVhen in operative position upon the rotor two of the arms 14 and 15, project into the space between two of the discs 10 in such position that two of the rods 12 may extend through their apertures 16 to rigidly hold the third arm 13 extending radially be yond the periphery of the discs 10. The arms 13, 14 and 15 are preferably symmetrical, as shown, so that when one end or radial extension becomes worn, the three armed plate may 9 be turned and a new end brought into service. As shown in Figs. 3 and 4, the radially pro jecting arms 18 are preferably arranged in six longitudinal rows, equally spaced circumferentially of the rotor, but only two arm V or housing 2.

members are positioned in the space between any two discs. The arms in each space are advanced one longitudinal row beyond the arm in the next preceding space, thus producing spiral lines of arms extending around the rotor from end to end thereof, and giving, when the machine is in operation, a continuous and progressive action on the material under reduction, and generating a substantially continuous surface on which the material will be supported.

\Vith this arrangement of arms there will be provided, when the rotor is in motion, a substantially continuous surface, the circumference of which is conventionally indicated by the dotted line in Fig. 3. \Vhen the rotor is at speed the continuous surface thus generated will substantially support or float thematerial under reduction and hold it in suspen sion and in mobile condition in the chamber Reduction of the material will be effected by the action of the arms 13 as they revolve against the surface of the mass, and the action being a steady and uniform one, a uniform product will result. The relation of the rotor with its engaging elements 13 to the chamber or housing 2 is such that the material under treatment is reduced princi pally by the action of the reducing elements as they strike the mass, as distinguished from its being dragged down into and crushed be tween rotor and opposed abutments, as in the usual type of crushing machine.

In the arrangement here shown to illustrate my invention, the housing 2 is above and encloses substantially the upper half of the rotor, although it is conceivable and entirely possible that the housing might be otherwise disposed relative to the rotor, and contains the reducing chamber 17 in which the prin cipal reducing operation occurs. The housing 2 has the end walls 18, bolted to the flanges 6 of the base frame, and joined together at the rearward side of the breaking chamber by the casing plate 19 and hopper plate 20. At the forward side of the housing 2 the end walls 18 are held by the draw bolt 21, from which is suspended a plate 22 to close the forward side of the reduction chamber. A goose neck bracket 23, attached to the lower side of the plate 22, is engaged by the rotary adjusting screw 2* threaded into a suitable nut 25 attached to the main frame. Manipulation of the screw 24 effects the adjustment of thelower edge of the plate 22 towards or from the rotor. here hard material is being reduced, and the interior surfaces of the housing 2 are exposed to the abrasive action of flying fragments coming from the mobile mass held up in the chamber by the action of the rotor, they are protected by suitable lining plates formed of any suitable material, as, for example, a refractory alloy of iron, and the plate 22 is protected by the lining 26 having, at its lower edge, a shelf 27. The upper surface of th1s shelf 27 extends along lines which are substantially radial of the rotor, to points in close proximity to the path of rotation of the ends of the arms 13, and forms an abutment which engages advancing material and acts to prevent the passage of oversize fragments downward from the breaking chamber into the lower part of the casing under the action of the rotor and its reducing arms 13, and so ensures a floating condition of the material upon and above the rotor.

Adjustment of this abutment 27 through the devices just described relative to the path of travel of the reducing elements 13, in this case carried by the revolving rotor 10, enables me to vary, to a considerable extent. the size of the output of the machine. A close adjustment of the abutment 27 to the path of travel of the reducing elements 13 will result in fine material, and adjustment away from the path of travel will result in coarser material. This is due to the fact that the relation of abutment and reducing elements determines, to a large degree, the size of the material which can flow downward to the screen below, a course adjustment permitting larger pieces than a fine adjustment. This arrangement, together with the screen through which the material ultimately passes, and which will now be described, enables me to control the output of the machine, so far as size is concerned.

The casing is closed beneath the rotor by a semicylindrical screen, concentric with and in close proximity to the path of travel of the ends of the arms 13, and this screen is adapted to permit fine material to pass out of the casing and to retain such small percentage of fragments as may have passed down through the rotor and are too large to pass through the screen, within the influence of the arms 13. This screen may take various forms, but preferably is formed of a series of longitudinally disposed bars 28, the spacing of which determines the size of the maximum fragments of the product. The screen thus formed may be divided into two sections, and in such construction, the forward section 29 will be rigidly supported by flag ges 30 cast integral with the main frame, and the rearward section 31 supported by a frame 32 hinged upon a longitudinally extending shaft 33, and held in working position by the toggle levers 34. The toggle levers 34 are fixed to a shaft 35 journaled in apertures in the casing walls, and a rocker arm attached to the shaft 35 may be provided to actuate it. By rotating shaft 35 the screen section 31 may be dropped away from the rotor to permit the removal of unbreakable objects, which may accidentally find their way into the machine and get below the rotor, and a counter-weight 37 attached to the rocker arm 36 serves to return the screen section to and maintain it in operative position.

It will be observed that with the construction here shown the rotor is completely enclosed or boxed by the closely fitting casing and screen, leaving exposed substantially the upper surface of the rotor surmounted by the hopper. This gives a definite area of material exposed to the action of the rotor, and the contents of the hopper, under the action of gravity, rest and float upon the rotor and are subjected to rotor action on the underside of the mass. The plate 22,,and its lining 26, and abutment 27, receives and resists any forward impulse imparted to the mass by the rotor, and the close relation of the abutment 2'? to the rotor prevents any tendency of oversize material to work downward into the rotor casin To attain maximum efficiency; maintain constant rotor speed, and prevent choking of the machine, the material which is to be reduced should be fed into the reducing chamberin asu'bstantially continuous and reasonably uniform stream. This may be accomplished by any preferred mechanism suitable for the purpose. For purposes of illustration in this embodiment of my invention, I have shown in the drawings a feeding device comprising a hopper 38 positioned above the machine, and terminating downwardly in a substantially semi-cylindrical chamber having the side Walls 39 and the revolving circular bottom plate 40. The bottom plate 40, as here shown, is mounted concentrically upon the end of a vertical shaft 41 to revolve with it. Obviously the plate 40 might be actuated by other means. The shaft 41 is supported in bearings 42 of the feeder frame 43 which is bolted to the main frame 1 of the machine. A worm wheel 44 attached to the shaft 41 is engaged by a Worm 45 mounted upon a horizontal shaft 46 which is driven through a pulley 47 and belt 48 from the rotor shaft 8. The feeder plate 40preferably projeots slightly beyond the upper edge of the casing plate 20, and a scraper 49 attached to the side wall 39 cooperates with the feeder plate 40 to transfer coal from the hopper 38 into the breaking chamber as said feeder plate revolves. Shield plates 50 and 51 attached to the plate 39 of the hopper are arranged to intercept flying fragments of coal projected from the reducing chamber, and a slide plate 52 is arranged beneath the hopper to permit adjustment of the feed opening from the hopper to control the rate of feeding.

In the reduction of coal, which is ordinarily supplied to steam power plants in the form commonly called run of mine and contains a considerable proportion of slack mixed with lumps of various sizes, a machine designed to and capable of preparing fuel for antomatic mechanical stokers should be adapted to break the lumps into uniform fragments of a size sufficient to insure the proper flow of air through the fuel bed, while small enough to be completely burned before being discharged into the ash pit, and such reduction shouldbe accomplished without materially increasingthe proportion of slack which is normally present.

In the illustration of my method and apparatus here given, and under normal operating conditions, the rotor will be driven at a speed to be determined by the character of the material under reduction. That speed must be sufficiently rapid to reduce thematerial without being high enough to bring about pulverization, and produce an excessive amount of fines. For example, to reduce the larger fragments of the average run of mine coal without increasing the slack, the rotor would be givena peripheral speed of approximately eighteen hundred (1800) feet per minute; The maximum size of the reduced output would, of course, be controlled by adjustment of the abutment 27 to the path of the reducing elements 13, as heretofore pointed out, and also by the spacing of the grate bars 28.

To produce half-inch stoker coal, the grate bars would be spaced one-half an inch apart, and the abutment approximately adjusted. For other sizes, the spacings of the bars and the abutment'would be altered to meet the conditions. K

In coal reducing operations, .run of mine coal, as above SDGClfiGCl, falls from the feeder plate 40 directly upon the ends of the arms.13

of the rotor, which arms, by virtue of their disposition and rotation, generate a substantially continuous supporting surface upon which the larger fragments of coal will float or be suspended. These floating lumps of coal roll upon the supporting surfaces of the rotor, and are prevented from traveling beyond and escaping from the breaking chamber 17 by the abutment 27. By this rolling and agitating action the coal in the breaking chamber is keptin a state of violent agitation, resulting in its rapid disintegration. Due to the spacing of the arms 13 both longitudinally and circumferentially of the rotor, the smaller fragments of coal fall between s a1 d arms, and, as the low speed rotation eliminates high centrifugal force, this fine material is permitted to flow through the skeleton rotor and the screen 29 so that the machine clears rapidly and output is higln VJhile I have shown and described the reduction of coal in this disclosure of my method and apparatus, it is, of course, adapted to the reduction of other materials, and the construction may be varied in many particulars. For example, instead of the grate bars 28, a plate having perforations of proper size to limit the maximum fragments of material might be used. In fact, equivalent devices for carrying out the method embodying the principles here set forth may be substituted for those disclosed and still be within the range of my development.

From the foregoing description, it will be seen that a method and apparatus is provided for the reduction of materials of various kinds, and particularly for those materials, such as coal, in which large fragments and fine materials are mixed, and from which it is desired to secure a uniform product, the maximum fragments of which shall be of predetermined size, and which product shall not have any material proportion of fine material added thereto.

Following my method and using my machine, as herein set forth, it will be seen thatthe mass of material which is fed in a uniform and continuous stream into the hopper is maintained during reduction in a suspended and mobile condition by the action of the continuously revolving surface generated by the rotation of the rotor, and that While in such suspended condition above the rotor and in the casing hopper, it is subjected to the reducing action of the radially disposed arms on the rotor. This method and this machine differs from the usual type of machine, in which it is proposed to reduce the material by subjecting it to a crushing action under hammer blows, as it is fed into a wedge shaped space between the reducing elements and an opposed wall. Vith the present construction, and in accordance with the method here disclosed, the reducing action takes place 'above the rotor, or equivalent element, and the relation of the rotor and casing and the construction of the rotor is such that large fragments of material are retained in the casing above the rotor until sufiiciently reduced to pass downwardly between the discs and arms of the skeleton rotor, so that practically none of the material, except that which has been first reduced to the proper size, can reach the screen below the rotor. The small percentage of oversize material which passes to the screen will be readily reduced, so that it will screen out as the final product by the action of the reducing elements which, it will be noted, have a path of travel close to the screen element.

Such variations from the construction here shown as are merely mechanical may be made, and equivalent expedients for those. used for illustrative purposes here may be adopted without departing from the range of my invention.

I claim:

1. In a machine of the class described, the combination of a rotor; a plurality of radially extending, rigid, reducing elements circun'iferentially disposed and spirally arranged longitudinally of said rotor and which, when the rotor is in motion, generate a substantially continuous revolving materialsupporting surface; and a hopper for the material to be reduced arranged above and closely embracing at its lower end said rotor to retain the n'iaterial in floating condition on said rotor and to prevent oversize material passing between said rotor and the lower end of said hopper.

A rotor for a machine of the class described having a skeleton frame to permit the passage of reduced material through the rotor; and a plurality of radially extending, ircumferentially disposed, and spirally arranged reducing elements extending from said skeleton frame.

3. In a machine of the class described, a skeleton rotor including substantially radially extending reducing members rigidly mounted in spaced relation to each other, and means for laterally and positively confining fragments above a desired maximum size of a fed mass of lump material to a top zone of the rotor periphery, whereby, the rotor being in rotation the fragn'lents of substantially the desired maximum size and under may fall immediately through the rotor or pass beyond said confining means, while fragments above the desired maximum size will be floated on said reducing members within said top zone until reduced to substantially the desired maximum size.

at. In a machine of the class described, a rotor comprising a skeleton frame made up of a plurality of disc'like members spaced from each other along the rotor axis, a plurality of rod-like fastening means extending through said discs, a plurality of substantially radially extending reducing members rigidly mounted on said rod-like fastening means between said disc-like members, and means for laterally and positively confining fragments above a desired maximum size of a fed mass of lump material to a top zone of the rotor periphery, whereby, the rotor being in rotation, the fragments of substantially the desired maximum size and under may fall immediately through the rotor or pass beyond said confining means, while fragments above the desired maximum size will be floated on said reducing members within said top zone until reduced to substantially the desired maximum size.

5. In a machine of the class described, a rotor comprising a skeleton frame made up of a plurality of disc-like members spaced from each other along the rotor axis, a plurality of rod-like fastening means extending through said discs, a plurality of substantially radially extending reducing members rigidly mounted on said rod-like fastening means between said disc-like members, the adjacent reducing members axially of the rotor being spaced by a distance greater than the distance between the outer sides of adjacent disc-like nwmbcrs. and means for laterally and positively confining fragments above a desired maximum size of a. fed mass of lump material to a top zone of the rotor, preferably, whereby the rotor being in rotation, the fragments of substantially the desired maximum size and under may fall immediately through the rotor or pass beyond said confining means, While fragments above the desired maximum size will be floated on said reducing members Within said top zone until reduced to substantially the desired maximum size.

In testimony whereof I have hereunto set my hand.

WILLIAM K. LIGGETT.

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