US1739855A - Comminuting mill - Google Patents

Description

Dec. 17, 1929. R. c. NEwHoUsE COMMINUTING MILL Filed Deo. 2o, 1928 Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE RAY C. NEWHOUSE, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS-CHALLIIERS 'MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE COMMINUTING MILL Application led December 20, 1928. Serial Nb. 327,209'.

The present invention relates in general to improvements in the construction and operation of rotary comminuting mills especially adapted for the reduction of granular material, and relates more specifically to improved structure for supporting rotary drum mills and for insuring effective reduction of material therein.

An object of the invention is to provide new and useful supporting and material distributing structure for rotary comminuting mills, whereby a relatively simple assemblage of elements will insure highly efficient ,reduction of the material. Another object of the invention is to provide an improved drum mill wherein a tire which is employed to rotatably support the mill, may also be utilized to inject material into the interior of the drum. A further object of the invention is to provide simple and efficient means for classifying material which has been partially treated in a mill, and for subsequently returning the separated grades to the mill for further treatment. Still another object of theinv'ention is to provide. an improved material screening system and mechanism for distributing the materials delivered from the screen. These and other objects and advantages of the invention will be apparent in the course of the following description.

Some of the novel features of comminuting mill and classifier construction disclosed butv not specifically claimed herein, form the subject of Patent No. 1,710,666, granted April 23, 1929.

A clear conception of an embodiment of the invention and of the mode of operating devices constructed in accordance therewith, may be had by referring to the' drawing accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the several views. v

Fig. 1 is a relatively diagrammatic illustra- `tion of a multiple compartment tube mill having the improved classifying device associated therewith.

Fig. 2 is a fragmentary enlarged part sectional side view of the tube mill and of the classifying device.`

Fig. 3 is an enlarged transverse section 'through the mill and through thesupporting tire thereof.

In the drawing, the multiple compartment comminuting mill comprises in general an elongated drum or shell 5 supported for rotation about a substantially horizontal axis, by means of a tire 10and rollers 9 coacting therewith at the feed end of the mill, and by means of a' trunnion 7 at the discharge end of the mill having a final discharge opening 20 therein. The mill is segregated into successive compartments 2, 3, 4, by means of screening .partitions 17, 18, and has a final discharge screen 19 associated therewith adjacent to the discharge opening 20. The shell 5 is adapted to be rotated about its longitudinal axis by means of gearing 8, and the successive compartments 2, 3, 4 are provided with freely tumbling comminuting bodies 21, 22, 23 respectively, of gradually diminishing size. The inlet end of the coarse grinding compartment 2 is provided with a feed inlet 6 and the compartment 2 is preferably formed of somewhat .larger diameter` than the other compartments 3, 4.

The shell 5 is provided with a series of peripheral discharge'openings 30 at the delivery end of the coarsegrinding chamber 2 and adjacent to the-screening partition 17. These openings in munication between the delivery end of the coarse grinding chamber 2 and the interior of an annular screen 11 which surrounds the shell 5 and extends toward the supporting tire 10. The screenA 11 is attachedl directly to the shell 5 at one end and is secured to the shell establish comthe tire 10 at its opposite end, being thus rotatable simultaneously with the mill.

conveyer screw 26 secured to the' interior ofv the screen 11, serves to urge material deliveed into the screen through the openings 30, toward the tire 10, and the latter is provided with lateral openings 15 formed to conduct the screen rejects into the interior of the tire.

The interior of the tire 10 is provided with a sectional trough-shaped liner 29 and with material return plates 27 which are formed to conduct the rejects entering the tire through the openings 15, toward the shell 5 during rotation thereof. The shell 5 is chamber is substantially balanced upon the rotary support afforded by the tire 10 and the Supporting rollers 9.

Disposed beneath the revolving screen 11,

i is a stationary trough 13, and the exterior of the screen 11 is provided with conveyer flights 12 which during rotation of the mill,Y

cooperate with the trough 13 to urge the screened material away from the tire 10 and into a stationary receptacle 14. A pair of spiral scoops 16 which are carried by the shell 5 beyond the first screening "partitions 17, are formed to dip into the receptacle 14 and to elevate the relatively fine material therefrom during normal rotation of the mill.

j The inne'1 ends of the scoops 16 are provided CTI with injectors 25 located within the shell 5, for returning the preliminary reduced material to the intermediate comminuting chamber 3 beneath the charge of comminuting bodies 22 therein. The portion of the mill which is located in proximity to the scoops 1G and the screen 13, may be shielded by av removable housing 2.8 which besides protecting the scoops and the screen, prevents escape of dust when the mill is operating. The housing 28 may be provided with suitable doors, not shown, for permitting access thereto.

During normal operation of the mill, the shell 5 is being rotated about its longitudinal aXis'by means of the gearing 8, and the material which is to be ground is admitted to the coarse grinding chamber 2 through the inlet opening 6. The admitted material is initially reduced in the chamber 2 by the action of the relatively large freely tumbling comminuting bodies 21 therein., and the partially disintegrated material is eventually delivered from the chamber 2 through the perforations in the partition 17 and through the peripheral openings 30, to the interior of the revolving screen 11. As the screen 1l revolves,

the convever screw 26 associated with the interior of the screen, gradually urges the material toward the tire 10 and causes the rel- Y atively fine particles to pass through the screen perforations from whence these particles drop into the trough 13. The relatively coarse material or rejects, is eventually delivered into the interior of the tire 10 through the lateral openings 15, and as the tire 10 revolves, these rejects are urged inwardly toward the shell 5 by the plates 27 and are returned to the medial portion' of the coarse grinding chamber 2 beneath the charge 'of comminuting bodies and material therein, by the injectors 24 as shown in Fig. 3. The relatively fine material deposited in the trough 13, is urged toward the stationary receptacle 14 by means of the conveyor flights 12 secured to the exterior of the screen 11, and substantially fills the receptacle 14 as shown in Fig. 2. The revolving scoops 16 which dip into the stationary receptacle 14 remove the relatively fine material therefrom and inject the said material to the inlet end of the intermediate comminuting chamber 3 beneath the charge of comminuting bodies 22 therein, through the vinjectors 25. In the intermediate chamber 3, the admitted material is further reduced by the freely tumbling communiting bodies 22 as it advances toward the second screening partition 18. After having been further reduced in the intermediate comminuting chamber 3, the material is eventually delivered through the partition 18 to the inlet end of the fine grinding chamber 4. In the chamber 4 the material is finally reduced by the relatively small freely tumbling comminuting bodies23, and the final product is eventually delivered past the discharge screen 19 and from the mill through the discharge opening 20.

From the foregoing description it will be apparent that the material admitted to the mill is treated in the successive chambers 2, 3, 4 to gradually reduce the same to a ne powder. f Each .of the several chambers is provided with freely tumbling comminuting bodies which are best adapted to effectively f reduce the material treated inl that chamber. In view of the fact that the relatively large comminuting bodies 21 are effective initial reducers when acting with considerable impact, it is desirable to make the coarse grinding chamber 2 of relatively large diameter as compared to the fine grinding chambers, so as to increase the peripheral velocity at the chamber 2 and thereby increase the cascading action of the charge in this chamber. As the charge within the initial or coarse grinding chamber 2 is relatively heavy, it has been found desirable to support the inlet end of the mill on a tire 10 instead of on a trunnion such as is customarily used at the discharge end of the mill. By placing the tire 10 at the medial portion of the coarse grinding chamber 2, the charge within this chamber is substantially balanced upon the tire.

With the construction of vthe present invention, the tire 10 may also be utilized for the purpose of returning the screen rejects to the medial portion of the coarse grinding chamber 2, it being most desirable to admit these rejects at this portion of the chamber 2. The interior of the tire 10 may be provided with liners 29 adapted to efectively resist thewear, and the openings 15 being of relatively small size do not materially impair the strength of the tire. The conveyers 26,'12 serve to effectively distribute thematerial and to keep the screen 11 from clogging. These conveyers being attached to the screen l1 function automatically during operation of the mill, and the classifying screen 11 serves vto enhance the capacity of the mill by permitting rapid delivery of the sufficientl reduced material from the coarse grinding chamber 2. Such material if ypermitted to remain Within the chamber- 2, undesirably cushions the impact action of the bodies 2l, and can be more effectively treated with smaller comminuting bodies such as employed in the intermediate chamber 3. The scoops 16 likewise serve to automatically inject the material delivered from the coarse grinding chamber 2 to the intermediate chamber 3, during-operation of the mill, and the entire assemblage obviously -provides a relatively simple and highly efficient structure for effecting reduction of the material.

It should-be understood that it is not desired to limit the invention to the exact details of construction and operation herein shown and described, for various modifications Within the scope of the claims may oc cur to persons skilled in the art.

It is claimed and desired to secure ters Patent:

l. In combination, a rotary shell forming acomminuting chamber, a tire rotatably supporting said shell and having a passage communicable with said chamber, means for classifying material delivered from said chamber, and means for returning material from said classifying means to said chamber through said tire passage.

2. In combination, a rotary shell forming a comminuting chamber, a plurality of freely tumbling comminuting bodies Within said chamber, a tire surrounding said chamber and rotatably supporting said shell, said tire having an internal passage communicable with said chamber, means for classifying material delivered from said chamber, and means for returning material from said classifying means to said chamber beneath said bodies and through said tire passage.

3. In combination, a rotary shell forming a comminuting chamber, a tire rotatably supporting said shell and having a passage comntunicable with said chamber, a screen for classifying material delivered` from said by Letlchamber. and means, for returning rejects from said screen vto said chamber through said tire passage.

In combination, a rotary shell forming a cemminutin chamber, a tire rotatablysupporting said s vfell and ha: ng a passage communicable with said chamber, anannular screen surrounding said chamber and rotatable with said shell for classifying material delivered from said chamber, and means for returning rejects from within said screen to said chamber through said tire passage.

5. In combination, a rotary shell forming a comminuting chamber, a plurality of freely tumbling comminuting bodies Within said chamber, a tire surrounding said chamber and rotatably supporting said shell, said tire having an internal passage communicable with said chamber, an annular screen also surrounding said chamber and rotatable with said shell for classifying material delivered from said chamber, and means for returning rejects from Within said screen to said chamber beneath said bodies and through said tire passage.

6. In combination, a rotary shell forming a comminuting chamber, a trunnion of less diameter than said shell rotatably supporting one end thereof,'a tire of greater diameter than said shell surrounding the opposite end thereof and rotatably supporting the same, said tire having a'passage communicable with said chamber, means for classifying material delivered-from said shell intermediatc said ends, and means for returning material from said classifying means to saidn chamber through 'said tire passage.

7. In combination, a rotary shell forming a comminuting chamber, means including a vtire for rotatably supporting said shell at its opposite ends, said tire having a passage communicable With said chamber, means for classifying material delivered from said shell intermediate said ends, means for returning material from said classifying means to said chamber through said tire passage, and other means for returning other material from said classifying means to the interior of said shell.

8. In combination, a rotary shell, means dividing said shell into successive chambers, a tire surrounding one of said chambers and rotatably supporting said shell, said tire having a passage communicable With said chamber, means for classifying material delivered from one of said chambers, means for returning material from lsaid classifying means to one of said chambers through said tire passage, and ,other means for returning material from said classifying means to another of said chambers.

9. In combination, a rotary shell forming a comminuting chamber, aftire rotatably supporting said shell, and having a passage communicable with said chamber, an annular screen surrounding said chamber and rotatable With said shell for classifying material delivered from said chamber, the interior of said screen communicating directly with said passage, a conveyer Within saidscreen for urging material therealong and into said tire 'chamberand being communicable With said adjacent to said tire and communicating directly with said chamber, means for urging material along said screen and into said tire passage, means for returning said material from saidtire to said chamber, and means for returning material which passes through said screen to the interior of said mill independently of said tire,

11. In combination, a rotary shell forming a comminuting chamber, a tire rotatably supportinfr said shell and having a passage com` municable with said chamber, an annular screen surrounding said chamber adjacent to said tire for classifying material delivered from said chamber, said screen being rotatable with said shell and communicating directly with said chamber and with said tire passage, means for urging material along said screen and into said tire passage, means `for returning said material from said tire passage to said chamber, a stationary trough disposed in proximity to said screen, and means for returning material from said said chamber, and means for deliveringmaterial to said tire passage whereby said Inal terial is introduced'into said shell through said tire passage.

15. In combination, a rotary drum forming a conuninuting chamber, a screen rotatable With said drum and formed to 'receive y material from a medial portion of said chamber, a stationary receptacle adapted to receive material passing through said screen, means for delivering material from said receptacle RAY C. NEWHOUSE.

trough to the interior of'said mill independl ently of said tire.

12. In combination, a rotary shell forming `a comminuting chamber, a tire rotatably supporting said shell and having a passage communicable with said chamber, an annular screen surrounding said chamber adjacent .to said tire for classifying material delivered from said chamber, said screen being rotatable With said shell and communicating directly with said chamber and with said tire p passage, means for urging material along said screen and into said tire passage, means for returning said material from said tire passage to said chamber, a stationary trough disposed 1n proxiimty to \.-sa1d screen, means associated with said screen for urging material along said trough, a stationary receptacle formed to receive material from said trough, and a plurality of scoops operable by said shell for returning material from said 'receptacle to the interior of the mill independently of said tire.

13. In combination, a rotary shell forming a comniinnting chamber, a tire rotatably sup'- porting said shell and having a passage communicable with said chamber, and means for delivering material to said tire passage whereby said material is introduced into said shell through said tire passage.

14. .In combination, a rotary shellV forming a comminutingchamber, a hollowtire rotatably supporting a medial portion of said shell and having. a passage communicable with figo

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