US2042254A - Pulverizer - Google Patents

Description

M. GODINEZ May 26, 1936.

PULVERI 2ER Filed Jan. 18, 1932 3 SheetsfSheet 2 ./wuw/whwj INVNTOR.

ATTORNEYS.-

May 26,v 1936.

'Y M. cacmlNEz` PULVERIZER Filed Jan. 18, 1952 3 Sheets-Sheet 3 f F2 f/ INVENTOR.

A TTORNEYS.

Patented May 26, 1936 'UNITED' STATES PATENT OFFICE PULVERIZER Manuel Godinez, Chicago, Ill.

Application January- 18, 1932,1Serial No. 587,253

23 Claims.

My invention relates to improvements in flne grinding machines and has for one object to provide a new and improved pulverizer or grinding machine of the ball mill typewhich while utilizing the well-known grinding effects of steel` grinding balls or pieces of steel rods and material to be ground and reduced, works almost exclusively by the cascade effect wherein as the cylinder rotates,'the mixture of charge and material to be reduced is carried around the periphery in a c'ompact mass, practically at internal rest, until a point is reached where the uppermost balls cascade down across the cylinder, crushing or grinding material as they move within the outer boundaries of the mass or as they bouncealong the inclined surface of the charge and they strike bottom and any material which may be there. 'I'his operation results in only a comparatively small percentage ofthe balls or grinding media boing at elfective work at any one time and only a comparatively small Ipercentage of the unreduced material in the cylinder being treated at any one time and hence it requires a great excess of grinding -media and time allowed for the operation in order to allow the majority of particles to be reduced to have the opportunity to be subject to the reducing effect of the grinding media sometime during their passage through the cylinder. All the above is exceedingly wasteful of space, grinding media, power and time because the excessive bulk of balls and material is quiescent to a large extent and must be continually lifted as it is being carried up around the periphery of the cylinder and because no positive means are provided within the cylinder to prevent some particles of material from passing through the full length of the cylinder without lbeing subject to a complete grinding action.

My solutionl of the problem contemplates the use of a xed housing generally circular in cross section divided into a large number of separate grinding lchambers by a plurality of rotors or discs supported on a longitudinal axle or shaft which substantially ll the cross sectional area of the cylindrical chamber and separatesteel balls or other grinding media contained between those relatively narrow grinding chambers or zones, spaced along the axis of the shaft. Owing to the narrowness of the space between the rotor discs and to the pressure exerted against their faces by the mass of balls and material they tend to rotate the balls themselves and carry them up along the periphery and accomplish not only the self-same cascading elect of the conventional tube mill but also tend to continually rotate and displace all the balls throughout the chamber and at the same time create a frictional grinding action between the face of the discs and all the balls in contact with it, also between the stationary cylindrical shell and those balls in contact with it. It is to be understood that the mass of grinding media is constantly subject to internal pressure due to theirv weight, and that this internal pressure causes a ,'onstant tendency of the media mass as a whole to bridge vor jam against the faces of the rotor discs. All grinding media in direct contact with the faces of the rotor disks have imparted to them a positive movement, by the bridging action against the rotor faces, which forces them to rotate and displaces them in response to the movement of the rotor, and regardless of whether the opposed faces of the rotor discs are deformed.

The faces of these discs are either flat or of irregular shape. or radially grooved according to the nature of material to be ground. When grooved they may have their opposed faces positioned so as to bring the groves in line or staggered, the alternate grooves and ridges increase the lifting and agitating effect on the ball charge and so increase the cascade effect and also creat'e 4a continual shaking motion within the mass of b alls and produce incipient separation in the material which tends to sift the fine particles down to the bottom and float the larger pieces towards the top where they will be again exposed to the crushing action between balls and rotating shaft and also subject to. the cascading effect. In some cases, considering in one chamber the ridges and grooves will be in opposition, in other cases they will be staggered. If they are in opposition, as the disc rotates, the chamber tends to expand and contract, moving the balls back and forth, up and down, also causing a jamming and nippingaction which will-.effectvely crush some of those particles caught between the adjacent balls. When they are staggered, the chamber tends to become slnuous and the whole charge moves back and .forth without change in overall width. In either event, the upward movement of the mass of balls and material along the periphery of the housing is less rapid than the rotary movement of the discs, and so the contact between the balls and the discs causes the outer balls to rotate; these balls being in contact with other balls cause them to rotate, thus there is a constant rotary movement of all the balls with respect to each other and this causes a positive grinding eect on all material surrounding the balls. Of course, there is movement of the mass back and forth and around against the lining of the cylinder, which also adds to the grinding effect so that the Whole mass of balls and material is, so to speak, alive and in motion and grinding is taking place atall times throughout the entire mass.

Experience in the past has shown that a better ne reduction can be accomplished in the ordinary tube mills by the use of partitions integral with the rotating shell which divide them into a plurality of grinding zones in series; starting at one end where the material is fed, with a zone containing large balls and going down through one or more stages to zones containing the smallest balls where the ultimate fine reduction takes place. In the past, stationary screens, screw conveyors, bucket elevators and specially designed air separators have been used to treat the material as it is discharged from one zone, pass on the lines to the next and return the coarse particles to any of the previous zones for further reduction. I propose to accomplish this by leaving a small clearance between the stationary housing and the rotating discs through which circular opening the iluid'pressure of the mass within the zone will force out the small particles of material, also in some cases by pro-I viding about thezperiphery of each of the rotating discs inclined vanes which tend to receive the material as it works out at the bottom of the zone between the disc and the liner, pick it up, carry it around and dump it into the next zone. When grinding dry material an air blast can be provided across the top of the mill and so arranged and regulated that it will increase the conveying action of the vanes by blowing the material lifted by them when it reaches the top of the machine into the next zone. This air blast will also tend to dissipate some .of the heat generated by friction within the machine and can be arranged so that it will carry in suspension some of particles of material which have Areached the limit of reduction, thus increasing lthe efliciency of the machine by automatically taking out of any and all zones some of the particles which can or need not be further reduced.

In the present grinding machines of the tube mill type, it is customary to feed the material through a hollow trunnion at one end and the finished product is discharged through a hollow trunnion at the opposite end; thus forcing the whole mass of feed to gradually work its way out through the full length of the mill, usually twenty feet or longer, thus requiring considerable time for the operation as the axis of ro- I tating cylinder is horizontal and there are not until only a very small percentage of partly reduced material comes out of the discharge end, all of which is wasteful of power, time and wear on grinding media.

My solution of this problem tontemplates preferably the provision of a central zone to receive the material and on each side of this central zone are an equal number of outer zones to contain grinding media and finally two end zones without grinding media but having suitable devicesto eject the finished product out of the mill. Material being fed to the central zone will gradually work its way down through it and automatically splits into two parts, each being forced to the two zones adjoining the central zone and is gradually forced to work its Way out to the end or discharge zones. This arrangement of feed point at the center of the machine with the discharge points at both opposite ends, reduces the horizontal distance which the material must travel to less than one-fourth of the distance they have to travel in the present tubemills. Preferably I arrange a single central coarse reduction zone wherein the grooves and ridges on opposed walls of the discs bounding the zone are in opposition. On each side of the this zone is an intermediate zone where thc ridges and grooves are staggered. Outside these two zones again are fine reduction zones where the ridges and grooves may be in opposition or staggered and there may be if required still further ne reduction zones where the ridges and grooves may be arranged as desired.

Experience shows that in the conventional type of ball or tube mill, there is a fairly denite relation between the total weight of ball charge and the capacity of its output in pounds per hour, hence if the ball charge in my mill is forced to give productive work at all times, the output per pound of grinding media used will be increased considerably.

Due to the excessive length of the present tube mills and to the weight of grinding media which they are to carry, a very heavy and expensive construction is required which added to the unbalanced load of the mass of grinding media and material which the rotating cylinder must continuously maintain at a certain position and at a definite speedto create the cascading effect essential to the grinding process, requires congrammatically in the accompanying drawings,-

wherein- Figure 'l is a longitudinal section;

Figure 2 is a detail fragmentary section along the line 2 2 of, Figure 1;

Figure 3 is a section along the line 3 3 of Figure 1;

Figure 4 is a section along the line 4 4 of Figure l;

Figures 5 and 6 are radial sections generally along the line 5 5 of Figure 3 but Figure 5 shows passing through two of the opposed grooves and Figure 6 through two of the opposed ridges to show the expansion and contraction of the chamber and the relative movement of the balls;

Figure '7 is a section along the line 1-1 of -Figure 4;

modified form;

Figure 9 is a plan view in part section of the same;

Figure 10 is an outside detail view of part ofthe housing showing the discharge aperture and chute.

Like parts are indicated by like characters throughout the speciiication and drawings.

A is a cylindrical housing closed at each endby the end plates A1 provided with longitudinal exterior reinforcing channels A2 and reinforced' at the ends by the supporting frame members A3'A4 andbearing brackets A5 A8 on which are mounted bearings AI A8. A9 A9` are handhole covers provided with liners A10 as indicated which when removed permit the withdrawal of .the charge of balls, there being a plurality of. these hand holes, one for each crushing zone `in the housing. A11 are hand hole covers in the upper portion of the housing .through which ballsmay be charged. vThey have no liners because they are at a point where the balls do notv normally come in contact.

Bis a shaft extending Alongitudinally through the center of the housing and rotatable in the bearings A'I A8. B1v is a gear on the shaft adapted to be engaged by any suitable means not here shown whereby power may be applied to rotate the shaft. The shaft extends through apertures in the end plates A1 and is provided with collars B2 at each end associated with dust labyrinth bearings to protect the bearingland prevent 'escape of dust. The shaft carries a plurality of thimbles B4 B5. Between these thimbles are a plurality of double sided discs or rotors B6 B".

Q At each' end of the shaft are single sided rotors Ba mounted on hubs B9 which extend out to the collars B2. These spools, discs and thimbles strung upon the shaft divide the housing into a plurality of separate pulverizing zones or chambers whose width measured along the length of the shaft is comparatively small but which extend throughout the. entire cross section of. the

hou'sing. Each of these zones contains a mass of balls. As shown, they are in three sizes, the

central having. the largest balls with enough small ballsvto fill the interstices between them, the next two intermediatezones contain inter-v mediate sized balls and the end ,zones contain the smallest balls. In general, this means that the cylinder is divided up into a central Jcoarse reduction zone, two intermediate reduction zones and at each end two fine reduction zones, though of course there might be only one of these at `each end but since the finer the material the more room required to treatit, it will be noted that vthe size of the two intermediate zones will be greater than the size of the central coarse reduction zone and the total volume of the two line reduction zones at each end will be considerably greater than the size of the intermediatezone adjacent to them.

Reference to Figure 2 shows sections through the discs or rotors. Each letter C represents a ridge and each letter C1 represents a groove. These ridges and grooves may be radial or may have any form, shape or direction that may be l found suitable.r 'I'he grooves and ridges are shown in the drawings as radially disposed and so expanding outwardly toward the periphery of the disc. It will be understood that this showing is merely illustrative and is not intended to re- Figure 8 is a detail vertical section through a I coarse vreduction zone ve the same ridge "at we have in the A n the outer ne reductionzones we have .t same arrangement that we have in the intermediate.' This staggering of the groove and ridge relation in some zones and ,alignment of grooves and ridgein other can be varied as desired. The arrangement shown is i preferable because it tends to equalize the load on the driving motor and because it tends to give a diiferent type of action in the different zones, thereby insuring `complete crushing, or pulverizing.` It will be noted that the discs are of -slightly less diameter than the housing so that there is space for the finely reduced material to pass into the space between the discs and the housing. The housing is provided with sectional circular liners D6, sized and shaped to provide adequate -clearance in relation to the discs, and to prevent the lodging of grinding rejects therein, and to compensate for wear. `It will be understood, of course, that the finely reduced material tends to ow under the inuence of gravity much like a liquid and the mass of material in each zone flows out from the bottom of it into the space between the periphery of the rotor or rotors bounding it and the housing. The peripheries of the discs may be rounded, sharp, ilat, or grooved, or of any other desired form. As shown in Figures i and 7, the peripheries of the discs or rotors are provided with inclined propeller blades C2, which blades form conveyor pockets so that the material which leaks out into the space about the periphery of the discs is fed laterally toward the next zone and is also picked up by the pockets as shown in Figure 4, and raised as the discs rotate, to the upper side of the houswhichV it passes into the next outermost pulverizing zone and also tends to pick upl any particles which have been sufficiently pulverized and carry them away so as to take them out of the pulverizing system and prevent their cushioning the uncrushed particles. In order that this air blast may not pass directly through the machine and to insure that only those particles vsufliciently light and fine be carried out, in some cases there are a plurality of baille plates D2 interposed in the upper part of the housing between adjacent rotors so as to constrain the air blast 't a tortuous h,ridge C is in op-- einnermost of the'V path. Encircling each rotor in that part of the housing where the liner is omitted, are a plurality of wear rings D3, one in opposition to each rotor. These wear rings have inclined vanes D4 projecting inwardly. The function of these rings and vanes is to protect the housing against the impact and wear of any particles which maybe picked up by the rotor and thrown outwardly by centrifugal force against the `wall of the housing and also to deflect any such particles into the nextadjacent zone so as to assist in the feed of material from one zone to the next. It is understood thatnfor the wear rings D1 I may substitute annular sections similar to the bottom liner D, suitably made to deilect from the disc edges particles of material or worn out grinding media, when so desired, vor the members D3, i1 desired, may be entirely omitted.

Referring again to the-relation between the ridges and grooves,` it will be noted that Figure 5 shows the position of the balls when they are between two grooves; Figure 6, the position oi the balls when between two ridges. The result of the various arrangements of the ridges and grooves is that as the discs rotate, the balls are moved toward and from one another in the central and two of the intermediate zones and the balls are moved as a body laterally along the shaft in the intermediate and two of the iine reduction zones. When the balls are moved toward and from one another, a squeezing or crushing effectA is produced. When they move as a body along the shaft a shaking orsifting effect is emphasized. It will be understood, of course, that as the discs rotate, they tend to raise the balls into a position shown in Figure 3 into a position high enough so that the balls cascade over the central shaft and by impact crush but because of the peculiar shape of the discs and because of the constant movement of the Aballs longitudinal of the shaft and because of the rotation of the balls imparted to them by the discs and imparted to the balls by one another, there is a constant grinding move- 'ment of the` balls so that the balls work throughout the entire area on the material surrounding them so crushing takes place everywhere 'along the line. v Reference to Figure 3 will show that the rotation of the discs, rotors or agitators tends to raise the 4mass of balls or pulverizing members along the periphery of the housing in the direction in which the rotor turns and that as this process continues, successive balls are raised above the shaft and cascade down over it and down along the slightly inclined surface of the mass of balls on ,the other side causing a. pulverizing effect by impact. At the same time the mass of balls to the other side of the housing tends to travel out toward the periphery of the housing `and so leave a space between the ball mass and the thimble or spool around the shaft as indicated. This Cil space is taken advantage of to insure that the material will immediately get into' the crushing area so the feed chute D5 is provided, adapted to discharge material into the space immediately adjacent the upstream side of the shaft so that th material will feed into the gap between the balls and the spool. It will be understood that there may be also a feed of material through the sleeve D. This material may be the oversize coming back from an air separator or other screening device, and is that small proportion of mateiial which has not been sufliciently reduced to ie standard neness required and therefore must be put once more through the pulverizing process. Material of a different kind, consistency, or nature, may also be added through the same sleeve D, which can be located at the center of the housing, or at any intermediate chamber of the machine.

Because the housing is at rest and because the rotors rotate in a mass of balls loosely contained in the housing and associated with the material to be crushed and because -the only contact be- `buckets or paddles E1.

tween the balls and the rotors is l. frictional contact, it will be obvious that the movement oi' the irregularly shaped rotors causes them to stir 'and agitate the material as well as to raise it or rotate it about the periphery of the housing. The result of this is that the balls travel or roll or slide along the periphery of the housing. The

. balls also roll and travel as a result of their and to the spool spacing the rotors on the shaft.

The impact or .cascade eiect which is'the only effect relied upon in the usual type of ball mill .to accomplish crushing is present to be sure in 'substantially the same degree, amount and eifect as is thev cascade and impact eifect in the usual type of ball mill but there is superposed upon which cascade and impact effect a very much more important and eective grinding effect caused by the relative movement under pressure of the balls, the rotors or agitators and the housing, as above indicated; and it is `the loosely supported separate pulverizing members which are agitated, displaced, rotated land moved about in unison and independently so as to permit every ball or other pulverizing member to be independently able to relate itself to those pulverizing members about it to accomplish a' pulverizing effect by actual grinding as distinguished from crushing which is characteristic of my invention,

At each end of the housing as above indicated is a. one sided 'rotor Bl. 'I'his one sided rotor is spaced from the' end of the housing so that there is a delivery chamber E at each end of the housing bounded on one side by the housing end and at the other by the rotor B0. This rotor may carry about its periphery and on the side opposed to the end of the housing, a plurality of It will be understood 'that the pulverized material flows out under the iniluence of gravity into the space between the |housing and the rotor B8 and thence intov the delivery chamber where it may be picked up by the paddles and carried to the discharge opening E, whence it is discharged into any suitable storage orV conveying receptacle as the case may be. 'I'he capacity of the paddles working in this chamber E is of course greater than the normally expected ilow of material to the chamber So that there is no danger of completed material banking up and preventing the outward flow of material from the pulverizing zones and of course this means that the level of material in these two discharge zones is so much lower than the l level of the material in any of the other pulverizing zones that a gradual and continuous flow of material from the coarse to the finest zone may take pia-eev during operation.

In the modified form shown in Figures 8 and 9, the rotating shaft is vertical instead of horizontal. The details and arrangement are very different but the theory of operation is substantially the same in that we havea pulverizing housing divided up into a plurality of separate pulverizing zones, each pulverizing zone containlng separate bodies or masses of loosely assembled and associated pulverizing members which are agitated and given relative rotation and movement with respect to one another and with respect to the housing to cause them to pulverize paddles G3.

These paddles travel in the upper portion of.

material associated with them, there being means for causing a flow of material as it is pulverized from the coarse reduction zone through an intermediate reduction zone to a ne reduction zone and thence out of the machine.

In the modied form F is a vertical shaft. It is mounted for rotation in an upper bearing F1, and a lower bearing F, being rotated by means of a mitre gear li'3 in mesh with a pinion noti here shown and mounted on the shaft F, driven by any suitablel source of power not here shown. F5 is the housing. The upper part has a relatively small diameter, the lower part a relatively large diameter. F*s is the rotor mounted on the shaft. In the upper small diameter, part of the housing is contained in an open ended lining sleeve F' which open ended lining sleeve extends down into the large diameter portion of the housing and has an upwardly and outwardlyared flange Fu which terminates in a rim F9 perpendicular to the axis of the shaft and adapted to engage the annular portion F10 of the housing.

G is a mantle on the rotor F6 concentric with the lining F" and extending down to a point substantially in the same 4horizontal plane as the lower boundary of the lining. This mantle and the lining F'7 form between themselves an annular chamber, which contains a mass of coarse reduct-ion balls G1.: laterally extending hollow disc G2 which disc is upwardly anged about its periphery as. at G3'. A lining G4 covers the upper horizontal portion and the inner outwardly flared portion of the flange G3 and is of such thickness that there is a gap between this lining and the lower edge of the fixed cylindrical lining F". The space between the upwardly inclined portion of the lining and the ange F8 on the cylindrical liner boundsa second coarse reduction chamber whichcontains a mass of coarse reduction balls G5, material being free to flow from the first coarse reduction chamber to the second. G6 is an annular liner in line with the flange F9 mounted on the housing and extending across substantially to the outer edge of the liner G4. It will be understood that when the shaft is rotated, the balls are agitated and they exert a' crushing and grinding effect on the material. The material flows in from the feed chute'G", isdischarged into the cylindrical pulverizing zone, passes down `through it under the influence of gravity, being pulverized as it goes, lis thrown out by centrifugal forcel into the annular chamber, is there pulverized and is then Athrownout by centrifugal force into the space surrounding the rotor where it is distributed by the the furtherl cylindrical chamber formed between vthe xed liner H located in the large diameter portion of the housing and a hner H1 bounding the outer periphery of the disc' G2. This annular or cylindrical chamber also containsfine reduction balls H3. The bottom of this chamber is bounded by a fixed ,liner H4, there being clearance between the xed' liner H4 and the liner H1 so thatmaterial may oyv by gravity through this clearance into a fine-:reduction chamber H5 which contains liners H and the housing H7 on the rotor and has between them a mass of pulvervizing balls H8 which balls also serve as an antifriction or rolling support for the weight of 'the apparatus. Just inside the inner periphery of 4the liner Hs is an annular pocket H9 in which travelI propeller blades H10 carried by the rotor. H11 is a discharge port leading to a chute H12,

Below the mantle the rotor has ath'e balls carry the material-around as it ows in from the fine reduction chamber and discharge it through the port to the chute. A Y

I is an air passage through the lower frame of the pulverizer. Material passes on through this 5 passage down .around an annular baiile plate I1, thence through a portI2 to the interior of 'the rotor, thence through ports I3 into the top of the annular chamber H13 and thence out through the port I". The function of this air is the same as in the preferred form. It assists Ain cooling the pulverizer. It assists in conveying the material as it is being pulverized and picks up and carries away that' rmaterial which has already been made sulciently fine.

It is to be understood that although the description and drawings show and describe cylindrical and conical housings and liners, I do not intend to be limited to these specific shapes, and any other suitable shapes may be employed, without departing from the spirit ofl my invention. However, I prefer to employ internal surfaces of housings and liners which are segmental portions'of involute surfaces 'generated by a regular or irregular line associated with the contour of the agitating rotor surfaces, and revol'ving about an axis generally parallel with the axis of the rotor.

It should also be understood that by housing I mean not merely the outer shell of the apparatus, but also the renewable or removable liners 4required to protect said outer shell, and the other parts of the apparatus which are associated with the outer shell,. and which constitute integral parts of the'housing. Also, although, the outer shell, liners, and associated parts of the housing lhave been indicated with plain and uniform surfaces, merely for the sake of clarity in illustrartion, said parts may be made in any shape required properly to fill their functions, and with 40 lsuch grooves, ledges, flanges, and wearing edges f as will permit maintaining their proper and xed positionin relation to the moving rotor.

Where the word fixed or generally-fixed is applied to the housing, it is understood that the term applies to the housing while normal grinding takes place and indicates the relationship between the rotor and the housing because, in the past, it has b een'commo'n to 1"itate the housmg in a machine of the tube or bau mill type. I propose to maintain the housing fixed against rotation, so that the grinding action of the present device is primarily responsive to, vand controlled by and caused by, the movement of the Irotor inside the housing, and in relation to the 5* housing, rather than bythe movement of the lhousing itself. j y

My experience has taught that under certain circumstances it isdesirable to mount the housing so that it may be rotated for prompt dumping of the ball and material charge, or to vary the position of maximum wear at various points of the housing. It will be understood that insuch case the housing isnone the less xed during the normal operation of the device.

AThe term continuous or imperiorate is applied to the discs with the intention of describing any disc which is either entirely free from perforations, or in which the perforations are so small that they prevent the passage of media therethrough and plug up or otherwise prevent the escape therethrough ofl .any substantial amount of material. In other words, I prefer to employ discs defining separate grinding corripartments, with the provision Ythat the media does not escape from compartment to compartment, and the particles of materials can escape from compartment to compartment mainly outside the periphery of the bounding discs.

I claim:

l. A pulverizer comprising a generally horizontal, generally cylindrical housing, arotor contained therein mounted for rotation about a horizontal axis substantially parallel with the axis of the cylinder, a mass of separate pulverizing elements loosely contained within the housing and in contact with the rotor, means for feeding raw material into the housing and for discharging pulverized material therefrom, the rotor being adapted toI impart relative bodily displacement Aancl individual rotary movement to practically of pulverizing elements at a point immediately,

adjacent the center of rotation of the rotor and on thel side thereof removed from the direction of travel of the pulverizing elements imparted to them by the rotor.

2. A pulverizer comprising a housing generally circular in cross section, fixed in position, a rotor shaft mounted for rotation about an axis generally lparallel wih the axis of the housing, a plurality of rotors on the shaft whose externalldiameter is slightly less than the internal diameter of the housing, propeller blades disposed about the perlpheries of .said rotors and generally inclined to the axis of the rotor, a mass of separatev pulver'- izing elements loosely contained within the housing and divided up into a series of separate zones by the rotors, means for feeding raw material to one of said zones, the propeller blades being responsive to the movement of the rotor to convey material from one z'one to another and means for discharging pulverized material from one zone. l

3. A pulverizer com prising a housing generally circular in cross section, nxed in position, a rotor shaft mounted for rotation about an axis generally parallel with the axis of the housing, a plurality of rotors on the shaft whose external diameter is slightly less than the internal diameter of the housing, propeller blades disposed about the peripheries of said rotors and generally lnclined to the axis of the rotors, a mass of separate pulverizing elements loosely contained within the housing and divided up into a series of separatey zones bythe rotors, means for feeding raw material to one of said zones, the propeller blades being responsive to the movement of the rotor to convey material from one zone to 'another and means for discharging pulverized material from one zone, the rotors being formed with a plurality of radially disposed corrugations whereby the movement of the rotors about their axes, the rotors being in contact with the pulverizing elements, impart movement to the elements along lines generally-parallel with the axis of the housing.

4. A pulverizercomprising a housing generally circular in cross section, xed in position, a rotor shaft mounted for rotation about an axis generally parallel with the axis of the housing, a plurality of rotors on the shaft whose external diameter is slightly less than the internal diameter ofthe housing, propeller blades disposed about the peripheries of said rotors and generally inclined to the axis of the rotor, a mass of separate pulverizing elements loosely contained within the housing and divided up into a series of separate zones by the rotors, means for feeding raw material to one of said zones, the propeller blades being responsive to the movement of the rotor to convey material from one zone to another and means for discharging pulverized material from one zone, the rotors being formed with a plurality of radially disposed corrugations whereby the movement of the rotors about their axes, the rotors being in contact with the lpulverizing elements, impart movement to the elements along lines generally parallel with the axis of the housing, the corrugations on the opposed faces of the rotors bounding one of the zones being angularly aligned whereby the width of the zone measured in the direction parallel with the axis of rotation expands and contracts about the peripheries of the rotors'.v

5. A pulverizer comprising a housing generally circular in cross section, fixed in position,la rotor shaft mounted for rotation about an axis generally parallel with the axis of the housing, a plurality of rotors on the shaft whose external diameter is slightly less than the internal diameter of the housing, propeller blades disposed about the peripheries of said rotors and generally inclined to the axis of the rotor, a mass of separate pulverizing elements loosely contained within the housing and divided up into a series of separate zones by the rotors, means for feeding raw material to one of said zones, the propeller blades being responsive to the movement of the rotor to convey material from one zone to another and means for discharging pulverized material from one zone, the rotors being formed with a plurality of radially disposed corrugations whereby the movement of the rotors about their axes, the rotors being in contact with the pulverizing elements, impart movement to the elements along lines generally parallel with the axis of the housing, the corrugations on the opposed faces of the rotors bounding one of the zones being angularly spaced whereby the distance between the two rotors measured -in a direction parallel to` the. axis is the same` throughout their entire periphery.

6. A pulverizer comprising a housing generally circular in cross section, fixedl in position, a rotor shaft mounted for rotation about an axis generally parallel with the axis of the housing, a plurality of rotors on the shaft whose external diameter is slightly less than the internal diameter of the housing, propeller blades disposed about the peripheries of said rotors and generally in clined to the axis of the rotor, a mass of separate pulverizing elements loosely contained within the housing and divided up into a series of separate zones by the rotors, means for feeding raw material to oneof said zones, the propeller blades being responsive to the movement of the rotor to convey material fromone zone to another and means for discharging pulverized material from one zone, the rotors being formed with a plurality of radially disposed corrugations whereby the movement of the rotors about their axes, the rotors being in contact with the pulverizing elements, impart movement to the elements along lines generally parallel with the axis of the housing and the opposed faces of the rotors bounding one of the zones having corrugations angularly alined, whereby the side of the zone expands and contr ts responsive to the movement of the rotor, and the;corrugations of another of the zones being angularly spaced whereby the distance between thetwo rotors measured in a direction parallelto' the axis-is the .same throughout their entire periphery.

7. A pulverizer comprising a housing generally circular in cross-section, a plurality of imperforate discs therein adapted to rotate about the ur horizontal axis of the housing, clearance between the outer peripheries of the discs and the inner periphery ofthe housing, means for introducing air under pressure into the housing, bafes bei tween the discs to constrain the air to a serpentine path about a part of the periphery of each disc and through the pulverizer chambers formed betweenadjacent discs and means for withdrawing the dust laden air after it has traveled such serpentine path. 8. A pulverizer comprising a housing generally circular in cross-section, a rotor therein,l renewable liners fixed in `position, in the housing associated with the rotor and adapted to divide the vhousing into a. plurality of separate pulverizingr chambers, pulverizing elements permanently con-f fined within each one ofl said chambers, there being passages from one chamber to another to permit the passage-of only they pulverized material in a free and continuous directional flow,

at least one wall of each chamber being formed by' the rotor whereby thev grinding -balls are interposed between moving rotor walls and., xed housing walls. o

7 9. A crushing machine comprising a housing generally circular in cross-section, fixed against rotation, having material inlet and discharge ports and air inlet and discharge ports, a 'rotor shaft extending through the housing along the central axis thereof, a plurality of rotor discs mounted on the shaft concentric with the housing and having their peripheries adjacent the housing, there being clearance between the peripheries of 'the disc and the housing at least sufficient for the passage of material therebetween, the discs having on their opposed faces radial corrugations,

the corrugations onone disc being angularly displaced with respect to the corrugations on the other, the discs being continuous and adapted to positively oppose travel along the housing except between the peripheries of the disc and the inner periphery of the housing, the discs being-spaced closely together so as to define a plurality of an- -nular crushing chambers, whose width in a direction parallel with-th shaft is materially less than the diameter of the housing, therefbeing a mass of freely moving grinding ballscontained within each chamber, thevolume of ballsv being such that when thefrotor is rotated, the balls are pumped -upwardly and forced to discharge over the rotor shaft.

l0.' In a reduction clevice, a fixed housing gen- .erely circular in cross-section, a rotor mounted for rotation in said housing about an axis extending longitudinally along the housing, and means for rotating the rotor, the rotor-including a shaft and a pluralityof imperforate discs 'spaced along said shaft and, adapted to dividef the interior of the housing into a plurality of reduction cham-- bers, and bodies of crus ng media in said chambers, the individual defining said chambers being sum'ciently close together to/ cause bridging and jammingfand to exercise a pumping or elevating action upon the media, whereby the particles of the media'cascade over the shaft.

1l. In a reduction device, a xed housing generally circular in cross section, a rotor mounted for rotation in-said-housing about an axis extending longitudinally along the' housing, and means for rotating the rotor, the rotor including a shaft and a plurality of imperforate discs spaced along said shaft and adapted to divide the interiorv of the housing into a plurality of reduction chambers, arid bodies of crushing media in said chambers, the individual discs defining said chambers being suiciently close together tocause bridging and jamming, an'd to exerciseV a pumping or elevating action upon the media, whereby the particles of the media cascade over the shaft,

,said 'discs being generally perpendicular to th`e axis of the rotor, but being slightly deformed.

12. In a reduction device, a xed housing generally circular in cross section, a rotor mounted for rotation in said housing about an axis l,extending longitudinally along the housing, and

means for rotating the rotor, the rotor includ- 'ing a shaft and a plurality of imperforate discs spaced along said shaft and adapted to divide the interiorof`\the housing into a plurality of reduction chambers, and bodies of crushing media in said chambers, the individual discs defining saidchambers being sufficiently close together to cause bridging and jamming, and toexercise a pumping or elevating action upon the' media, whereby the particles of the media cascade over the shaft,

said discs being generally perpendicular to the axis of rotation ofthe rotor, but being slightly deformed by corrugations ou their faces.

13. In a reduction device, a fixedv housing generally" circular in cross section, a rotor mounted for rotation insaid housing about an axis extending longitudlnally along the housing, and means for rotating the rotor, the rotor including a shaft and aplurality of imperforate discs spaced along said shaft and -adapted to divide the interior of the housing into a plurality of reduction chambers, and bodies of crushing media in vsaid chambers, the individual discs dening cause bridging and jamming, and to exercise a pumping or elevating action upon ,the media, whereby the particles of the media cascade over.

`said chambers being sufficiently close together to the shaft,y said discs being generally perpendicubers, and bodies of crushing media in said chambers, the individual discs defining said chambers being sufhciently close together to cause bridging and jamming, and to exercise a` pumping or elevating action upon .the media, whereby the particles Aoi." the media cascade over the shaft, said discs being generally perpendicular to the axis of rotation of 'the rotor, but being slightand grooves of opprsed disc faces being staggered. 15. In a reductionvdevice, a ilxed'lhousing gen-l ly deformed by ridges and grooves, the ridges` erallyl circular in cross section, a. rotor' moufntjed for rotation in said housing about an a'xis extending'iong-itudinally along the housing, .and

means for rotating therotoL-the rotor including l a shaft and a plurality of ifnperforate discs spaced along said shaft and adapted to'divide the interior of the housing' into a plurality of reduction chambers, and bodies of crushing media in said chamberathe individual discs defining said chambers being suiilciently close together to cause bridging and jamming, and to exercise a pumping or elevating action upon the media, whereby the particles of the media cascade over the shaft, said discs being generally perpendicular to the axis of rotation of the rotor, but being slightly deformed by corrugations, the corrugations of opposed disc faces. being in opposition to each other.

16. In a pulverizing machine, a normally ilxed housing,` generally circular in cross section, a grinding rotor adapted to rotate about the axis of the housing, comprising a central grinding drum and at least two projecting grinding iianges adapted to form grinding chambers, loose pulverizing elements in each of said chambers, mixed with the material to be ground, the projecting flanges being imperforate and being adapted positively Vto oppose travel of the loose pulverizing elements and the material from one chamber to anothen' except through the space between the periphery of the disc and the opposed portion of the housing, there being sufficient clearance to permit the passage therebetween of ground material, the clearance however being suillciently close to prevent the escape of the loose pulverizing elements of normal size from chamber to chamber.

17. In a reduction device, a fixed housing generally circular in cross section, a rotor mounted for rotation in said housing about an axis extending longitudinally along the housing, means for rotating the rotor, a plurality of imperforate discs spaced along said rotor, and adapted to divide the interior of the housinginto a plurality vof reduction chambers, bodies of crushing media gether to cause bridging and jamming of said media., and to exercise a pumping or elevating action upon the media, whereby the particles of the media cascade over the shaft, said housing including a portion overhanging said chambers, and adapted to confine said media, and thereby to assist said pumping action.

18. In a reduction device, a fixed housing generally circular in cross section, a rotor mounted for rotation in said housing about an axis vextending.longitudinally along the housing, means for rotating the rotor, a plurality of imperforate discs spaced along said rotor, said discs having a clearance about their peripheries, in relation to the opposed portion of the housing, sumcient to permit reduced particles to pass therethrough, and feeding means for delivering material to said chambers for reduction, said feeding means being positioned intermediate the ends of the housing. and discharge means for the reduced material, adjacent each 'end of the housing.

19. In a reduction device, a normally fixed housing generally circular in cross section, material inlet and discharge outlet means therefor, a moving rotor, mounted generally concentric with the housing, and including a plurality of discs the peripheries of which terminate in spaced relation with respect to the housing, ,said discs being adapted to agitate a mass of free pulverizing elements Within the housing, said discs being continuous, and being adapted to oppose travel of material along the housing, except between the peripheries of the discs and the opposed portion of the housing.

20. In a reduction device, a normally fixed housing generally circular in cross section, material inlet and discharge outlet means therefor, a moving rotor, mounted generally concentric with the housing, and including a plurality of discs adapted to agitate a mass of free pulverizing elements within the housingVsaid discs being continuous and dimensioned to provide clearance between the disc .peripheries and said housing, whereby to oppose travel of material along the housing, except between they peripheries of the discs and the opposed portion of the housing, and renewable segmental liners associated with the housing and adapted to provide and maintain uniform clearance about the peripheries' of the discs.

21. In a reduction device, a moving rotor including a series of discs, a normally fixed housing, generally circular in cross section, in which said rotor is mounted, a mass of free pulverizingwithdrawing pulverized material therefrom, said latter means including circular end iianges associated with the rotor, and segmental liners associated with the housing, adapted to provide and maintain a substantially uniform clearance between said liners and the end flanges of the rotor, through which the finished material mayescape for withdrawal. f

22.- In a reduction device, a moving rotor including a series of discs, a normally fixed housing, generally circular in cross section, in which said rotor is mounted, a mass of free pulverizing elements within the housing, and opposed to said discs, segmental liners associated with the housing and adapted to provide and maintain suitable clearance about said discs, means for feeding material to the housing, and means for withdrawing pulverized material therefrom, said latter means including circular end flanges associated with the rotor, and segmental liners associated with the housing, adapted to provide and maintain a substantially uniform clearance between said liners and the end flanges of the rotor, through which the finished material may escape for withdrawal, the material feeding means being located intermediate the ends of the housing, and discharge 'outlet means associated with each end of the rotor` and housing.

23. In a reduction device, a moving rotor including a series of discs, a normally fixed housing in which said rotor is mounted, a mass of free pulverizing elements within the spaces defined by said discs, means for feeding material into thehousing, means for withdrawing material from the housing, and additional means for adding to or taking out material or pulverizing elements from the housing, While the'rotor is in operation, said means including apertures in the housing, and closures therefor, located at a level above the normal levels of the chargev of pulverizing elementswithin the housing.

iluminan. GoDmEz.

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