US1713297A - Centrifugal air-float pulverizer - Google Patents

Description

May 14, 1929.. 1 o, OLST N 1,113,297

" CENTRIFUGAL AIR FLOAI PULVERIZER Filed March 26. 1928 .l/VVENTOR 07m warm in German )atent paper No. 364 issued Sep- Patented May 14,1929.

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' My invention relatesv in general'to pulverizers and pulverizing methods, and has more particular reference to centrifugal ulverizers of the type illustrated and descri d tember 6, 18 7, granting to G. Mehler a patent on a grinding mill. Specifically my invention resides in modifying the device "described in the aforesaid German patent paper in such a manner that, in addition to the centrifugal grinding principle embodied in the device of the German patent, in improved mill employs a novel air flota on principle whereby the pnlverizing action may be accom lished in a more satisfactory and successf manner and which enables the accurateregulation and control of thesize of the ground material. 7 One of the important objects of my invention is to provide a mill which may be easily regulated for coarse or fine pulverization.

' Another important object of'm, invention is to provide a pulverizing mill 0 simplified and rugged construction whereby the parts may be readily disassembled for storage or transportationand in which the pulverizmg process embodies an air flotation principle whereby the material may be more satisfactorily pulverized and whereby an accurate control of the size of the pulverized'material ma be accomplished.

nother important object of my invention is to provide a novel method of pulverizing, embodying an air flotation process, whereby pulverizing action is rendered more uniform so that the material pulverized may have a substantially uniform texture.

Still another important object of my invention is to provide a novel grinding mill of simplified construction wherein the ar rangement of the parts is best adapted to carry out my improved method of pulverizing material and which, at the same time, provides a neat, simple, compact and rugged structure which may be readily assembled and disassembled for repairs and transportation and which may be manufactured at minimum cost.

Numerous other objects and advantages of the invention will be apparent as it is more fully understood from the following description which, taken in connection with the accompanying drawings, discloses a preferred embodiment of the invention.

Referring to the drawings:

Figu

1928. Serial No. 264,827.

Figure 1 is a vertical cross section of a pulverizmg mill embodying my invention;

re 2 is a horizontal cross section taken through the mill illustratedin Figure 1; and

Figure 3 is a perspective view ofa breaker mai of my invention,v showin the spacer blocks whereb the ring may suspended in the casing o the mill to ermit the. successful operation. of my novel air flotation process.

'To illustrate my invention, I haveshown on the drawings a two sta e grinding mill having a substantially cylin rical case or shell 11 in which breaker rings 13 are carried in position to receive material discharged by centrifugal action from a rotatable breaker mechanism including horizontal breaker discs 15 carried on a shaft 17 mounted for rotation within the'shell. The shell 11 is supported on suitable legs 19 and is provided with a discharge chute 21 at'its lower end, a cover 23 enclosing the upper end of the shell. The shaft 17 .is journalled atfits lower end in a roller thrust bearing 25 arranged in a housing 27 formed'in a cross member 29 arranged across the lower end of the shell 11, and at its upper end in a roller bearing 31 arranged iii a housing 33 formed centrally of the cover '23, suitable protective devices including packin 35 being judiciously arranged to exclude grit and the like from the pulverizer from.

enterin and destroying the bearings. A dust cover 3% also is secured to the shaft and ens closes the open end of the housing 27 while a cover 39 is arranged to enclose the open end of the housing 33.

The breaker mechanism comprises spaced plates or discs 15 carrying suitable impeller blades 41 adapted toassist in directing the material, being pulverized, outwardly onto the breaker ring. The plates are adapted to slidingly thread upon the shaft and-are maintained in spaced relationship by means of spacing members 43 which are also adapted to slidingly thread upon the shaft between the discs. The plates and spacers are keyed to the shaft or otherwise suitably secured to rotate therewith and are clamped in position between a shoulder 45 formed at the bottom of the shaft and a clamping screw 47 which has threaded engagement with the shaft at its upper end. The shaft is provided at its upper end with a pulley 49 whereby rotational movement may be imparted to the breaker construction as embodied in a grinding;

V mechanism, and it will be apparent that, when the discs 15 are" rotated, material deposited centrally thereon will be thrown outwardly against the breaker rings by centrifugal action and be pulverized. J

The breaker rings are not, as is the usual custom, mounted directly tothe shell walls but are spaced from the shell by means of integral spacing members 51 which are arranged about the rings so that there is an air space or channel 53 between theback of the v rings and the shell. The breaker rings and the integral spacers are formed as a unit to fit within the shell, with the outer surfaces of the spacers engaging the walls of the shell,

- and the lower breaker ring unit rests upon an integral intu'rned flange 55 formed in the shell above the su port member 29. Immediately above each breaker unit and supported go within the shell by the upper ends of the spacing members 51 is a hopper or funnel 57 having peripheral edges 59 adapted to fit into the shell and a central orifice 61 arranged to discharge material into the central portions of the discs 15. The breaker ring units and the hoppers or funnels are stacked alternately and secured firmly in position in the shell by means of clamping screws 63 arranged in the cover 23 and it will be apparent that the various parts arranged within the casing may be most easily assembled and disassembled by merely removing the cover 23 and lifting out the parts which may be easily raised'from position within the casing.

Each breaker ring is provided with the usual corrugated breaker surface against which the material to be pulverized may be thrown, but I have provided an inwardly ex tending annular flange portion 65 opposite the peripheral edge of the co-operating breaker disc in order to reduce the clearance between the disc and the breaker ring to the least possible dimension. By manufacturing refinements, whereby the parts are accurately made, this clearance may be reduced to such an extent that very little pulverized material will be discharged from the stage through this interstice, and practically all of the material willhave to be discharged from the stage through the aperture or channel 53 .between the breaker ring and the shell.

I have provided a feed hopper 67 in the cover 23, and an air vent 69 is also conveniently arranged in the cover. This air vent may be of any convenient adjustable type whereby the amount of air entering the shell therethrough may be regulated.

It will be apparent that upon rotation of the shaft, the breaker mechanism including the discs and the impeller blades 41 comprises a fan, and that the intermediate funnels 57 form air baflies which together with the fan action of the breaker mechanism produces a draft which is drawn into the stage through the central aperture 61 of the funnel 57,

thence passes radially outwardly acrossthe breaker disc 15 and upwardly over the breaker ring and downthrough the space 53 between the breaker ring and-the shell and finally passes radially inwardly to be discharged through the central orifice of the funnel 61 of the succeeding stage.

The material pulverized in a stage will thus be carried by this draft from stage to stage until finally discharged from the mill. This comprises my novel flotation process. The draft will lift or float the pulverized material of below a certain size from a pulverizing stage over the top of the breaker ring so that the material being pulverized will remain in a pulverizing stage until reduced below a certain size depending upon the strength of the air draft, that is to say, the amount of air passing through the stage per unit of time it being apparent that the stronger the draft the larger and coarser will be the particles floated out of the stage. By regulating the amount of air admitted through the vent 61 I am able to control the texture of the material ground. When a finely ground product is desired, theiair vent is closed and the machine allowed to operate on restricted draft and vice versa when a coarse grade is desired the vent is opened, and I contemplate also the provision of supplementary blowers for augmenting the draft when a specially coarse grade is desired. Of course when the air draft is restricted the grindingoperation occupies a greater time interval than when a forced draft is provided.

For purposes of illustration, I have shown a two stage grinding mill, that is to say, a mill having two pairs of breaker rings and co-operating discs and impellers but it will be apparent that my novel invention is not limited to any particular number of stages but may beembodied in a mill having any desired number of pulverizing stages.

One of the principal advantages of the grinding mill of my invention resides in the simplicity of its construction whereby the parts may be most readily assembled and disassembled in the casing. The parts also are so designed that they may be manufactured at minimum cost. further advantage resides in the neat and compact arrangement whereby a mill of maximum capacity and minimum space requirement is provided.

It will be apparent also that numerous changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing any of its material advantages, the form hereinbefore described being merely a preferred embodiment of the invention. 7

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A pulverizer having a breaker ring and a cooperating rotatable impeller mechanism enclosed within acasing. means for spacing said breaker ring from said casing whereby to provide a discharge channel between the ring and the casing, and a hopper supported from said breaker ring in position to deposit material to be ground interiorly of said impeller mechanism and to act as a bafilc whereby in conjunction with said impeller mechanism to create a draft through said channel.

2. A pulverizer having a grinding'stage comprising a breaker ring and co-operating rotatable impeller mechanism arranged within a casing, means for spacing said breaker ring from the casing to provide a channel therebetween, and a combined hopper and battle supported by said breaker ring in position to deposit material centrally of the impeller mechanism and to cooperate therewith so that when the impeller mechanism is rotated, a d 'aft may be created through said channel whereby to float pulverized particles from the stage, said impeller mechanism and breaker ring having substantially co-terminous portions whereby pulverized particles are substantially prevented from passing downwardly from the stage between the ring and mechanism.

3. A pulverizer having a breaker ring and an impeller mechanism including a rotatable disc arranged within a casing, said ring being spaced from the casing and having a flanged portion substantially co-terminoits with the disc.

4. A pulverizer having a grinding stage comprising a breaker ring and an impeller mechanism including a rotatable disc arranged within a casing, the ri being spaced from the casing to provide a dlscharge channel providing the escape of pulverized material from the stage around the ring, and said breaker ring having an inwardly projecting flanged portion substantially coterminous with said disc, whereby pulverized material is prevented from passing from the stage between the flanged portion and the peripheral edge of the disc.

5. A pulverizer comprising a casing, a-

breaker ring concentrically mounted within the casing, means in the casing and cooperating means in the breaker ring for supporting and spacing said breaker ring from the casing" to provide a channel between the breaker ring and the casing, a breaker mechanism comprising an imperforate disc rotatably mounted within the casing with its peripheral edge extending opposite the breaker ring and heaters mounted to the edge of the imperforate disc in position to move across the inner face of the breaker ring upon the rotation of the disc, a chute for directing material to be pulverized into the central portions of the disc and means for supporting the chute above the breaker ring and a cover for enclosing the upper end of the casing whereby to clampingly secure the chute, the

breaker ring and the positioning means in place within the casing.

6. A pulverizer comprising a casing and ably mounted within the breaker ring and having a peripheral edge extending opposite the breaker ring and heaters mounted to the edge of the disc in position to move across the inner face of the breaker ring upon the rotation of the disc, and a conical chute havmg an outer edge adapted to engage the inner. walls of the casing supported in placeby the spacing blocks above the breaker ring, said chute being formed to direct material to be pulverized to the central portion of the disc, whence it maybe projected radially outwardly by centrifugal action and pulverized against the breaker ring, said chute being arranged to form a battle adapted to cooperate with the heaters upon the rotation of the disc whereby to create a draft radially outwardly across the disc over the breaker ring and through the channel whereby pulverized partlCiOS may be floated from the pulverizing stage when they reach a desired degree of fineness.

7 A pulverizer comprising a casing, a breaker ring supported within the casing, means formed in the casing and cooperating spacing blocks formed in the breaker ring for supporting the breaker ring, impeller means mounted within the casing and adaptedto discharge material to be pulverized radially outwardly onto the breaker ring, a chute arranged within the casing having a peripheral edge engaging the inner walls of the casing and being supported in place above the breaker ring in position to deposit material to be pulverizedinto the central portions of the disc, said chute being supported by the breaker ring spacing blocks, and a cover arranged across an end of the casing and having means whereby to secure the chute and breaker ring in position within the casing whereby, upon removal of the cover, the parts within the casing may be readily removed.

8. A pulverizer comprising an open ended casing, a breaker ring and a superimposed material chute arranged within the casing, means formed in the casing for su porting the breaker ring and chute in stac ed relationship within the casing, said breaker ring and chute having portions engaging the walls of the casing for the purpose of aligning the no i , material chute arranged within the casing,

means formed in the casing for supporting the breaker ring and chute in stacked relationship within the casing, said breaker ring and chute having portions engaging the walls of the casing for the purpose of aligning the breaker ring and chute therein, said chute being formed and arranged to deposit ma terial to be pulverized centrally of the breaker ring, means formed and arranged in the casing for clamping the chute and breaker ring in position therein, impeller mechanism comprising a shaft supported within the easing, means formed and arranged in the easing for supporting the shaft rotatabl within the casing, a radially extending isc car'- ried by the shaft opposite said breaker ring and beneath said material chute in position to receive material to be pulverized from the chute and to discharge said received material against the breaker ring, said breaker ring having a ortion substantially coextensive with a disc whereby pulverized material ma be prevented from passing downwardly tli erebetween.

10. A pulverizer having a plate adapted to rotate in a horizontal plane and adapted to receive the material thereon to be pulverized and to throw the same radially outwardly by its rotation, an imperforate breaker ring disposed concentrically about the periphery of therotatable plate and upstanding vertically therefrom, and a casing surrounding the breaker ring and rotatable plate and spaced from the breaker ring so as to provide a channel, said parts being constructed and arranged so that the material pulverized by the cooperation of the impeller mechanism and the breaker ring may be discharged upwardly and over the top of the breaker ring. a

11. A pulverizer comprising a casing, a substantially vertically disposed shaft therein, an impeller plate mounted within the easing and adapted to be rotated by said shaft and lying in a horizontal plane, a breaker ring concentrically surrounding. the periphery of the impeller plate and being substantially co-terminous with the periphery of the propeller ring but slightly spaced therefrom whereby pulverized particles are substantially prevented from passing downwardly between the ring and the plate, said breaker ring providing an upstanding imperforate breaking surface having an open top, and a casing surrounding said breaking ring and spaced from the top and rear wall thereof so as to provide a channel permitting the pulverized material to flow upwardly over the top of the breaker ring.

12. A pulverizer including a casing and having a rotatable disk arran ed horizontally within the casing, and a brealer ring concentrically surrounding the peri her of the disk and providing a vertical rea ing surface, said ring having its inner portion substantially co-terminous with the periphery of the disk and spaced slightly therefrom whereb to permit relative rotation between the dis and the ring, while substantially preventing pulverized particles from passing downwardly between the disk and the ring.

In witness whereof, I have hereunto subscribed my name.

OTTO OLSTON.

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