US 2562560 A
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July 31, 1951 J. H. MACARTNEY APPARATUS FOR CENTRIFUGAL PULVERIZING AND SEPARATING Filed Jan. 18, 1946 4 Sheets-Sheet 1 INVENTOR. lL// Ma4cm July 31, 1951 J. H. MACARTNEY APPARATUS FOR CENTRIFUGAL PULVERIZING AND SEPARATING 4 Sheets-Sheet 2 Filed Jan. 18, 1946 INVENTOR. Jw/b /7e/7/mr//E BY July 31, 1951 J. H. MACARTNEY APPARATUS FOR CEIN'IRIFUGAL PULVERIZING AND SEPARATING Filed Jan. 18, 1946 4 Sheets-Sheet 5 rm/mm July 31, 1951 J. H. MACARTNEY.
APPARATUS FOR CENTRIFUGAL PULVERIZING AND SEPARATING 4 Sheets-Sheet 4 Filed Jan. 18, 1946 INVEN TOR. Job n 507056 2 rney BY ATTORNEY Patented July 31, 1951 I APPARATUS FOR CENTRIFUGAL PULVER- IZING AND SEPARATING John H. Macartney, San Francisco, Calif.
Application January 18, 1946, Serial No. 642,035
This invention relates to an apparatus for grinding or pulverizing, and is particularly for the comminution and reduction of loose and broken lumpy material, such as ores, coal, cement, rock, clay and the like, to a required fineness of mesh. This application is a continuation in part of application Serial No. 554,186, filed September 15, 1944, now abandoned.
The features of the present invention include the grinding of the material by means of particles of the material thrown off by centrifugal force into contact with other particles of the material so that the grinding is efiected by bombarding certain particles of the material by freshly introduced particles; the grinding is accomplished in a grinding chamber formed between oppositely rotating bodies in each of which a portion of the material is so restrained as to form grinding surfaces or linings on the inner peripheries of the respective rotating bodies; particles of said material being drawn through sald chamber and into the path of the centrifugally thrown particles by suction which is partly created by the rotation of said linings and bodies; the said linings and bodies being preferably rotated in opposite directions, and pref erably these rotating bodies being positioned one in the other and being rotated oppositely to oneanother.
An object of the invention is to utilize the centrifugal force for imparting grinding velocity to particles of the material directed into a grinding chamber and to utilize the same force for moving particles in the path of the centrifugally thrown particles and to move the material ground to suitable fineness out from said chamber.
Other objects of the invention together with the foregoing will be set forth in the following description of the preferred embodiment of means for practicing the same, which is illustrated in the drawings accompanying and forming part of the specification. It is to be understood that I do not limit myself to the embodiment disclosed in said description and the drawings as I may adopt variations of my preferred forms within the scope of my invention.
A preferred embodiment of the invention is clearly illustrated in the accompanying drawings, wherein:
Fig. 1 is a cross-sectional view of an embodiment of my invention, the section being taken on lines |l-l--l 01' Fig. 3;
Fig. 2 is a sectional plan view of the apparatus, the section being taken on the line 2-2 of Fig. 1;
Fig. 3 is a sectional plan view of the apparatus, the section being taken substantially on lines 3-3 of Fig. 1;
Fig. 4 is a sectional, fragmental detail view of one of the screened outlets from the outer cone of the apparatus;
Fig. 5 is a sectional, fragmental view showing said outlet covered;
Fig. 6 is a sectional view of a modified form of my invention;
Fig. 7 is a fragmental, sectional top plan view of the outer cone of the modified form with side outlets, and
Fig. 8 is a plan, diagrammatic view indicating substantially the paths of the opposed streams in the device.
In carrying out my method of grinding and pulverizing material such as ore, clay or the like, the material is fed centrally into a rotating inverted cone closed at its apex and open at its base so that the centrifugal force carries the particles of material upwardly along the inner periphery of said cone. The material is re-' strained partially so as to form into a lining layer on the inner periphery of the cone. Particles of the material from the surface of this layer are impelled by the centrifugal force upwardly and radially outwardly from the base of the cone across and into a grinding chamber formed between the aforementioned cone and a spaced exterior cone rotated concentrically with the first cone. The material in this outside cone is rotated in opposite direction to the rotation of the material in the inner cone and it is restrained partially so as to form a layer or lining on the inner periphery of this outer cone. The particles of material in the inner layer are rotated at a much higher speed than the particles of material in the outside layer and in the chamber. The centrifugal force of the outer layer urges the particles in said chamber upwardly and toward the portion of the chamber which is adjacent to the area into which the particles from the first cone are ejected by the centrifugal force. In effeet, the particles in the outer layer are carried in a continuous stream into the path of the stream of particles centrifugally fed from the inner layer and are practically bombarded by the particles flying off from the base of the inner cone. A feeding effect in an upward direction is created by the rotation of the inner cone to facilitate the upward movement of the particles from the outer layer and into suitable position for the bombarding action of the outwardly flying particles. The whirling particles which move ascaseo 3 at a high speed work against the respective layers ofparticlesintheinnerandouterconeso that the particles of material form also the wearing surfaces during the grinding. Thus, in my method, the particles of material successively operate for grinding the previously introduced particles of material by a bombarding action and also form protective linings which provide the wear surfaces during the grinding. The feeding into the inner lining or cone is soperformed that the material is introduced near the apex of the inner cone. The upward draft produced by the rotation of the opposite linings and cones moves the particles upwardly in the grinding chamber and allows the heavier particles to drop back and be again advanced for further bombarding action and grinding. The dropping heavier particles contact the lining in the outer cone and are held up and urged upward again by the centrifugal force exerted on them by the rotating outer cone. Thus the material in the outer cone is prevented from falling through the open bottom of said outer cone. The lighter particles of flner mesh are also carried upwardly by said draft and out through an outlet passage, which is suitably restrained to pass only particles of a desired fineness. The ground material is then collected and removed at a point above said rotating mechanism. I
In the preferred form of my invention, as illustrated inthe drawings. I use an inverted hollow cone 8, the apex I of which is clomd and thebaselofwhichisopen. Theapex'lofthe cone 6 is mounted on a shaft 0 which latter in turn is supported in suitable bearings I I in frame members I! and on a base l3. On the cone base I is formed a restraining rim ll projecting inwardlyoftheconeisoastorestrainaportion of the material in the rotating cone in such a way that a layer of material is formed all around the inside wall of the hollow cone 6 producing aprotectivelininginthecone. Therim II has converging sides cross-sectionally and the outer inclined sides of the rim ll assists somewhat in directing particles of the material to fly substantially radially outwardly from the cone base 8. The outer face ii of the rim I4 is comparatively flat and then tapers outwardly of the cone and downwardly so as to give corresponding direction to the particles flying oi! the cone base 8.
Around the outer periphery of the cone is formed a gritting or grinding chamber II. The outer wall of this chamber i1 is formed by an inverted frusto-conlcal shell ll spaced from the outer surface of the inside cone 6. A portion of the wall of this outer shell I! is substantially parallel and concentric with the outer surface of the inner cone 6, but this parallel portion terminates at a level I! which is below the level cfthebaserim lloftheinnerconet. The wider mouth or base II of the outer shell II is inclined at a steeper angle than the conical portion of the shell It and extends above the level of the base rim ll of the inner cone 6. On the inner periphery of the shell II is a restraining flange 2! which extends at an angle upwardly and toward the inner cone 8. The function of this flange 22 is to collect certain of the material adjacent the wall of the shell ll into lining which lining then completely covers the inner surface of said shell is. In the top of the outer shell II is a cover plate 23 which extends outwardly beyond and outside the top edge of the shell ll and forms a circular centerin: flange 24.
Averticalframeflextendsfromthebase l3 upwardly and spaced from the outside of the shell ll. Onthetopofthhsframeitarerotatably mounted a plurality of Miler rollers. The outer periphery of the centerhig flange II is in frictional contact with the peripheries of the idlerrollersllsothatastheshell llrotates itwillcausetherotationoftheidlerrollers 28 which latter center and guide the shell ll.
Theinnerconetisrotatedinonedirection andtheouterconicalshell llisrotatedinthe opposite direction by any suitable means. In the present illustration an electric motor or the like, not shown, is connected by suitable transmission.'suchas abelttransmimionutothe shaft! which latterisshowminthepresent illustration,flxedtctheapex1ofthecone8by means of a key 33.
In the present illustration the shell It has an annular base flange u on its outer periphery spaced from the lower end thereof and facing downwardly. A plurality of supporting rollers II are rotatably mounted on brackets 36 on a frame member if undersaidilangefl. Thebaseflange 34 rides on the supporting rollers 35 when the shell I. is rotated and supports the shell ll. Sli htly above and outsidethe flange 34 is formed aringgearflontheshellll. Adrivegearll isinmeshwiththeringgearll forimparting rotation to the shell II. The drive gear 38 is keyed on a drive shaft I. which latter is journalled in bearing brackets II on the frame members i2, and is driven by any suitable power drive through a suitable transmission, such as the belt and pulley drive 4|. The transmission heretofore described is arranged for rotating the shell II in a direction opposite to the direction of rotation of the cone S. The relative rotative speeds are preferably such that the speed of rotation of the shell it is considerably lower than that of the inner cone 8. For instance, for certain purposes of grinding certain materials, the cone 6 is rotated at about 2000 revolutions per minute in one direction while the outside cone or shell II is rotated at about 500 revolutions per minute in the opposite direction.
Above the cover plate 23 is formed a collecting chamber I by a lid 52 which is supported on suitable brackets 53 extended from the top of theverticalframefl. Ahoppermbe I4 issecuredinthecenterofthclidil andisextended downwardly and through the cover plate 13 and intotheconeitoapointnearthe apexl of saidconei. Materialisfedintothishoppcr tube 54 at a funnel top 58 in any suitable manner. From the lid 52 extends a delivery conduit 51 which is connected to a booster fan or blower indicated at it in Fig. 1.
On the outer surface of the cone 6 are provided a plurality of vanes i! at a suitable angle to create a draft or blast upwardly through the gritting chamber l1 and toward the cover plate 23. The cover plate 23 has a plurality of outlet openings GI therethrough, covered by screens 62 of suitable mesh so as to allow only particles of predetermined fineness to be discharged from the grinder.
Each outlet opening Cl is surrounded by flanges $3. defined by concentric arcuate sides and a pair of radial sides, and all the openings 6| lie at the same radial distance from the center of the cover plate 23. Inasmuch as the cover plate 21 rotates with the shell II in a counter-clockwise direction viewing Fig. 2, the arcuate side flanges Itistobenotedthateachopeningilis 63 are inclined so as to present a higher edge Bl as the leading edge in the direction of rotation as shown particularly in Fig. 4. Each screen 62 is arranged to follow the incline of the arcuate flanges 63, so that the screens 62 also incline downwardly toward the trailing end oppositely to the direction of rotation of the cover plate 23. This inclined arrangement produces a lift or suction above each screen 62 and facilitates the drawing of the ground particles through said screens 62.
A set of outlets 68 is arranged near the center of the cover plate 23. These outlets 66 are adjustably controlled by a valve plate 61 which is rotatably held by set screws 68 which latter are slidable in arcuate slots 89 on said valve plate I. The valve plate 61 has a pair of opposite openings H. In the position shown in Figs. 1 and 2 of the drawings, the central outlets 66 are covered by the plate 61. When greater fineness is desired, the valve plate Bl is turned until the openings II are in a desired alignment above the outlets 66 for forming the desired opening. When the central outlets are used, the outer outlets 6| are covered by plates 12 as particularly shown in Fig. 5. This selective adjustment is accomplished after raising the cover or hood 52 sufficiently to gain access to the top of the cover plate 23.
At the bottom of the shell ll are openings I3 covered and adjusted by a valve plate 14 similar in structure and operation to the valve plate 61 heretofore described. The bottom openings 13 are adjusted for the desired intake to maintain a balanced pressure condition for the air flow through the shell l8.
In the modified form of the invention, shown in Figs. 6 and 7 an apparatus is shown to carry out my invention in connection with wet material. This apparatus and the principle of operation is substantially the same as heretofore described in the first form, with certain differences. The cover plate 23' is entirely closed, and outlets 15 are provided along the periphery of the shell 18. In each outlet I5 is a screen 16 of suitable mesh. The shape of the shell I8 is different in that the lower portion is sloped at lesser incline to the horizontal. The outlets 15 are below the level of the upper edge l6 of the inner cone 6. The wet material is agitated and is moved continuously upward in the outer shell I8 by the centrifugal force and it is subjected to bombardment by the outwardly thrown particles from the top of the inner cone 6 repeatedly, and is also ground by continuous contact in its relative movement upon each other. The particles ground to the desired size are permitted to escape through centrifugal force through the outlet screens 16 and are collected by any suitable means not shown.
In Fig. 8 is shown diagrammatically the general path and direction of the movement of the particles from the inner cone and in the outer shell. The outer shell rotates in counter-clockwise direction and the inner cone rotates in clockwise direction viewing Fig. 8. It was observed that the particles from the inner shell follow substantially the paths indicated by the broken lines and arrows 11. The paths of the particles ejected by centrifugal force from the inner cone are substantially radial and curve toward the direction of rotation. The particles in the outer shell l8 move substantially on curved paths indicated by broken line arrows in Fig. 8. These paths 18 are along the inner conical surface of the lining layer or of the shell II, and move upwardly and also toward the direction of rotation of the outer shell 18. The horizontal streams of particles ejected with high speed from the inner cone 0 collide with and bombard the particles which move upwardly and substantially outwardly on the paths 18 in the outer shell IS. The rotational direction and force on these particles is at an intersecting angle with respect to the horizontally thrown particles. The general movement of the particles in the outer shell i8 is upward although not exactly on a vertical path. The particles in the outer shell collide also with one another and during the movement along the outer shell the frictional contacts therein effect further attrition or comminution of said particles. When these particles in the shell [8 reach into the path of the substantially horizontal stream of particles ejected from the inner cone 6, they are effectively bombarded with still greater force. By the combined frictional forces and collisions between the particles a comparatively speedy and uniform pulverizing or comminution is accomplished. The upward movement of these particles is maintained in a comparatively balanced draft, namely, the blower or fan 58 produces a suction to draw the particles out through the respective discharge outlets Bl or 66. The vanes 59 on the outer periphery of the cone 6 create a draft upward to feed the air in the direction of said suction. The bottom intakes 13 of the outer shell I 8 are adjusted to admit the necessary air for a balanced upward air current which aids in the discharging of the finely ground particles through said outlets, but permits the heavier particles to fall back into the outer shell l8 and work in the aforesaid described paths into repeated collisions with other particles until reduced to desired fineness.
In operation the material is fed centrally through the hopper tube 54 and is introduced into the rotating inner cone 6 near the bottom apex 1 thereof. The method and apparatus herein described performs the attrition of particles of the material to be ground by collision between streams of such particles travelling on intersecting paths athigh velocity imparted by centrifugal force. For instance a cone of about 29%" diameter, may rotate at a speed of 1750 revolutions per minute and it will discharge the particles in a substantially horizontal plane at the base of the cone at about 14,000 feet per minute into and across the grinding chamber ll. The centrifugal force urges the particles of material upwardly in the cone and radially outwardly at the base rim ll of the cone 6. Certain of the particles closer to the inner surface of the cone 5 are partly obstructed and restrained in their upward movement by the rim flange I4 and accumulate into a circular lining or liner on the inner surface of the cone 6 so that the particles moving at high speed impinge upon the liner of the material instead of upon the surface of the cone 6.
The outer cone or shell I8 is rotated at a lower velocity than the inside cone 6. For instance, with an outer cone of 42" diameter at 200 revolutions per minute, it would move particles collected in said shell H3 at a velocity of about 2200 feet per minute generally upwardly and in the path of the stream of particles discharged at a higher velocity from the inner cone 6. The two streams of particles so driven collide in the grinding chamber i1 and this collision between the two streams of particles breaks up the particles into smaller pieces and performs the grindassasao will not impingeupon the material of the shell II but this liner so formed will take up the wear and also causes further attrition of the particles of material to be ground. During this opposite rotation of the inner cone 6 and the outer shell II, the vanes 59 on the outer surface of the inner cone 6 move within the grinding chamber l1, create a blast of air which may reach a velocity of about 12,000 feet per minute in connection with structures of the size heretofore mentioned.- The ground particles will fall back into the chamber i1 and against the liner layer on the sides of the shell [8 until ground to such a fineness that they can pass through the screen 62 of the outlets GI and carried away from the collection chamber through the discharge conduit 51. There is a rotary clearance between the lid 52 and the flange 24 of the cover 23, and to prevent lateral escape of ground product, I provide an annular shield 19 extending upwardly from the cover 23 along the inside periphery of the lid 52. This upward blast or draft created by the vanes 59 also cooperates with the centrifugal force in the device for moving the particles upwardly and preventing them from falling through and out the open bottom of the frustoconical shell it. It is to be understood that the dimensions and speeds of rotation above enumerated are merely for the purpose of illustration as they were found operable in connection with certain types of material to be ground, but applicant does not wish to be bound or limited to any dimensions or rotating speeds described herein for the purpose of illustration.
The principle of operation of grinding material by driving two streams of particles of such material at high speed so as to collide with a bombarding effect utilizes the centrifugal force of the oppositely rotating cones and the layers of linings of the same material on the wearing surfaces of said cones and makes use both of the centrifugal force created and also of the wearing action on the lining for grinding the particles of material to a desired fineness. It accomplishes the grinding with greater efllciency and in comparatively greater volumes; it reduces the wear of the revolving parts participating in the grinding operation, the wear being taken up by the liners created by the material itself; it also reduces the comparative power per unit required for a desired output; it operates continuously and uninterrupted without the danger of clogging or breakdown from the point of the introduction of the material to be ground near the apex of the inner cone i, then upwardly and outwardly, forming the lining in the inner cone and flying off at a high speedinto the grinding chamber I] through the upwardly travelling stream over and from the lining layer of the outer cone or shell IS. The two cones operate preferably with a vertical axis, as shown, concentrically in opposite directions at suitable relatlve speeds, not requiring any adjustment or any regulation during the continuous operation of the grinder.
1. In 'a machine of the character described, a hollow inverted cone, and an outer shell around said cone having upwardly diverging walls spaced from said inner cone, means to rotatably support said cone and shell on a substantially vertical; common axis of rotation, means to rotate said cone and said shell in opposite directions to one another. and to rotate said inner cone at higher speed of rotation than said outer shell, the base of the inner cone being adapted to throw particles of material substantially laterally outwardly from the inner cone against the outer shell, the angle of incline of the walls of said outer shell guiding the particles dropped into said outer shell upwardly and across the path of the particles thrown off from the base of the inner cone.
2. In a machine of the character described, a pair of hollow elements having upwardly diversing walls, one element being disposed within substantially parallel with and spaced from the other, means to rotate said elements in opposite directions to one another around a common vertical axis and to rotate the inner element at a higher speed than the outer element, means to feed material to be comminuted into the inner element, said inner element being adapted to eject by centrifugal force particles of said material toward the outer element and into forceful impact with other particles of material urged upwardly in the outer element by centrifugal force of said rotation, and retaining means in each of said elements to retain part of the material in the respective elements in the form of lining layers on the inner surfaces of the respective elements.
3. In a machine of the character described, a frame, a hollow inverted cone rotatably supported in the frame, an outer shell with upwardly diverging walls spaced outside of the first cone, a sup: porting flange extended outwardly from the top of the outer shell, rotary aligning means to rotatably support said flange and said outer shell on said frame, means to rotate said cone and said shell in opposite directions to one another about a common vertical axis and rotate the inner cone at a higher speed than said outer shell, retaining rims on the cone and on the shell for retaining part of the material in the form of conical linings therein, the top edge of the inner cone directing particles of material thrown off by centrifugal force laterally outwardly into impact with other particles moved by centrifugal force upwardly in said outer shell, and impeller blades formed on the inner cone and extended into the space between said cone and shell for creating an upward draft between said cones.
4. In an apparatus of the character described, a frame, a hollow inverted cone rotatably supported on the frame, a hollow inverted substantially frusto-conical shell rotatably supported on the frame, rotating outside of and being concentric with said first cone, said cone and said shell diverging upwardly, means to rotate said cones in opposite directions to one another around a substantially vertical common axis, the upper? edge of said inner cone being adapted to throw material therefrom laterally against said outer' shell, means to feed the material to be treated into the inner cone adjacent to the apex thereof, and outlet means for discharging material comminuted to desired fineness from said outer shell.
5. In an apparatus of the character described, a frame, a hollow inverted cone rotatably supported on the frame, another hollow inverted cone rotatably supported on the frame, rotating within and being concentric with said first cone, said cones diverging upwardly, means to rotate said cones in opposite directions to one another, means to feed the material to be treated into the inner cone adjacent to the apex thereof, and outlet means for discharging material comminuted to desired fineness from said outer cone, said outlet means including a cover plate on said outer cone spaced above the base of saidinner cone, a lid above said cover plate forming a discharge chamber, and outlet ports on said plate discharging into said chamber, the said outlets being arranged in a pair of concentric series at diflerent radial distances from the center of rotation of said cones, and means to close the respective series of outlets and at will.
6. In an apparatus of the character described, a frame, a hollow inverted cone rotatably supported on the frame, another hollow inverted cone rotatably supported on the frame, rotating within and being concentric with said first cone, said cones diverging upwardly, means to rotate said cones in opposite directions to one another, means to feed the material to be treated into the inner cone adjacent to the apex thereof, and outlet means for discharging material comminuted to desired fineness from said outer cone, and a series of outlets on the periphery of the outer cone below the level of the base of the inner cone.
7. In an apparatus of the character described, a frame, a hollow inverted cone rotatably supported on the frame, another hollow inverted cone rotatably supported on the frame. rotating within andbeing concentric with said first cone, said cones diverging upwardly, means to rotate said cones in opposite directions to one another, means to feed the material to be treated into the inner cone adjacent to the apex thereof, and outlet means for discharging material comminuted to desired fineness from said outer cone, said outlet means including a cover plate on said outer cone spaced above the base of said inner cone, a lid above said cover plate forming a discharge chamher, and outlet ports on said plate discharging into said chamber, flanges surrounding said outlets and extended upwardly into said chamber, said flanges being provided with higher leadin edge in the direction of rotation, and a screen in each of said outlets arranged at an incline upwardly toward the direction of rotation of said cover plate and of said outer cone for creating a lift above said screens in said outlets.
JOHN H. MACARTNEY.
REFERENCES CITED The following references are of record in th file of this patent:
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