US1504777A - Comminuting mill - Google Patents

Description

Au@ a2 92@ y www? R C. NEW/HOUSE COMMINUTING MILL Filed April '7 1921. 2 Sheets-Sheet l @wv/Mm @2&1 l fw A@ 12 m@ @www R. c. NEW/HOUSE COMMINUTING MILL Filed April '7. 1921 2 Shees-Sheet B Patented Aug. 12, 1924.

UNITED STATES PATENT OFFICE.

RAY C. NEWHOUSE, 0F WAUWATOSA, WISCONSIN, 'ASSIGNORIO 1ALLIS-(iB ALMERS MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A. CORIPORATION OIE DELAWARE.

COMMINUTING MILL.

Application led April 7, 1921.

To all 'whom t may concern:

Be it known that RAY C. NnwHoUsn, a citizen of the United States, residing at VVauwatosa, in the county of Milwaukee and State of 1kWisconsin, has invented a certain new and useful Improvement in Comminuting Mills, of which the following is a specitic-ation. l

This invention relates in general to improvements in the art of reducing materials such as mineral, hard animal or vegetable substances, by impact and abrasion, and relates more specifically to. improvements in the construction and operation of rotary drum mills for comminuting materials with the aid of a plurality of tumbling. bodies such as balls, pebbles, rods and the like.

An object of the invention is to provide a comminuting mill which is simple in construction and eiiicient in operation.

It has been found in the operation of tube mills, ball mills, rod mills and the like, that considerable available energy is ordinarily wasted due to Athe cushioning of the tumbling comminuting bodies, by thematerial which is in pulverulent condition. rl`his tine material lodges upon the comminuting bodies and packs about the larger particles of material whichrequire further reduction, thereby preventing the cascading and tumbling comminuting bodies from effectively pulverizing the larger particles of the charge.

In order to make available this energy which is ordinarily wasted due to the cush ioning effect produced by the tine particles ofmaterial, the present invention contemplates removal of the tine material from the charge, at one or more points along the mill. The invention also contemplates return for further reduction, of the relatively large particles of material which are discharged from the mill during the process of elimination of the fines. y A

A further object of the present invention is to provide a mill which will deliver eX- ceedingly uniform and line material at the final discharge. Another object of the invention is to provide a simple and compact comminuting mill in which the parts which are subjected to excessive wear, are readily stages of the mill.

Serial No. 459,332.

accessible forinspection and renewal. An additional object of the invention is to provide a compound or multi-stage comminuting mill having screening means of ample capacity between the successive grinding` 55 The invention further contemplates the provision of other imp rovements in construction and operation of mills of the generalchavracter referred to, whereby the cost of manufacture is reducedjto a minimum and the eiiiciency of operation is increased to a maximum.

A clear conception ot several embodiments of the invention and of the operation of devices constructed in accordance therewith, "3 may be had by referring to the drawings accompanying and forming a part of this specification, in which like reference char acters designate the same or similar parts in the various views.

Fig. 1 is a somewhat diagrammatic central vertical' section through a rotary combination comminuting mill embodying means for separating the material which has been suiticiently reduced in the first grind- 75 ing stage, from the oversize; the mill being provided with means for delivering the separated material ,to the second stage for nal reduction and with other means for returning the oversize material to the first stage for further reduction. f..

Fig. 2 is an enlarged transverse vertical section through the combination comminut-` ing mill, part of the section being taken through the mill division head, 'and another part being taken in front of the division head with reference to the direction of flow of the material through the mill. y

Fig. 3 is an enlarged transverse vertical section through the combination comminut.- 'U ing mill, the sect-ion being taken through the instrumentalities for returning material which requiresfurther reduction, to the second stage of the mill. p

Fig. 4f is a purely diagrammatic illusa tration of a rotary combination comminuting mill provided with means for introducing material to the mill at a point intermedi ate its ends.

Figs. 5 to l1 inclusive are purely dialoo materials, which may be utilized to ad` grammatic illustrations disclosing various combinations with respect to the flow of Vantage with mills constructed in accordance with the present invention. j v' The rotary combination or two-stage. comminuting mill disclosed. in detail in Figs.

1 to 3 inclusive, comprises in general a rotary drum orshell 1 which may have uni'-,v

form diameter throughout its. length, the shell 1 being provided withl feed and discharge end heads 2, 3 respectively, and having therein a partition or division head 4 which divides the shell 1 .into successive coarse and fine grinding chambers 5, 6 respectively, these chambers constituting the stages of the mill. The mill is rotatably mounted in suitable trunnion bearin 7, 8 located in proximity to the 'end ' head 2, 3 respectively, Vand is adapted to be continuously rotated about its horizontal center line v at a desirablespeedvby means of power applied to a driving one end of themill.

The preliminary or coarse' grinding chamber 5 is lordinarily filled to near the gear 9 associated with horizontal center line of the shell 1 with' relativel 'large freely tumbling comminut-v 10, 11 are free to tumble and cascade within the chambers 5, 6, and are preferably lforme-d of material which will effectively resist impact and abrasion. The bodies- 10,

11 may assume a 'variety of forms and may.

in some cases be shaped as rods extending substantially the entire length of the chamber within which they are located. VThe raw material is fed into the coarse grinding chamber 5 through an inlet trunnion 70.

' lVithin the chamber 5 the material is partially reducedby the action of the large comminuting 'bodies 10, the partially reduced material which is of'suficient fineness to pass through the holdback plate 19 and screen 14, being delivered to a receptacle 17 located below and entirely loutside, of the mill. From the receptacle below the mill, vthe material whidh has been discharged from -the first grinding stage through the screen 14, isV delivered vto the fine grinding or finishing chamber 6 vby means of a pair of return scoopsi'l formed as shown in Fig. 3. The material thus de livered to the fine grinding or second stage, is further reduced in the chamber by the action of the tumbling comminuting bodies 11. The finally 'reduced materialv is eventually delivered from the finishing chamber through a discharge screen 26 ,and 'into the' path of elevating vanes '12 which automatically discharge the fine material from y ing plate 19 preferably'formed in sections,

an'imperforate Wall disposed parallel to the plate 19, a plurality of radial ribs 23 which divide the space between the plate and wall into a Aseries of chambers 22 communicating directly with the coarse grinding chamber 5 through perforations in the plate 19, an annular sizing screen 14 completely surrounding the mill and spaced therefrom to form an annular screening chamber located outside of the shell but communicating with the chambers 22 through radial openings 20 in the shell 1, diametrically opposite re-. -jects return vanes 13 having adjacent conducting passages which are segregated from the'chambers 22, scoop plates 21 connecting the return vanes 13 with the screen 14, and return openings 25 extending from the vanes' 13 through a central projecting portion 18;which extends away from the par-V tition 4 and inwardly toward the feed end of the mill. The material delivered from the coarse grinding, chamber through the perforations in the holdback plate 19, drops by gravity through the openings 20 and upon the annular sizing screen 14. As this vmaterial'slides along the inner surface of the screen 14 during rotation of the mill, the relatively fine material passesthrough the vscreen perforations and drops into the receptacle 17 below. The scoop lplates 21 during each half revolution of the mill catch the oversize particles of material which have passed through the perforations in the ho-ldback plate 19 but which are too large to pass'through'the screen 14, and deliver'these oversize particles to the vanes 13 which periodically. shoot the collected batches of oversize material back into the medial portion of the coarse grinding chamf ber 5 throu h the return openings 25, for' further re uction by the comminuting bodies 10. The inwardly extending portion 18 of the division head 4 besides serving toQ provide passages for conducting the oversize into a medial portionof the chamber 5 and remote from the lplate 19, serve" to throw the relatively large comminuting bodies 10 into the medial portion of the` coarse'grinding chamber and away from the plate 19 vand the openings 25. By thus preventing th'e large tumbling comminuting bodies l0 from lodging in front of the plate 19, the material is permitted to pass through this plate with least obstruction thereby 'enhancing the capacity of the mill. A furtherv lrlO advantage in constructing the inwardly ex-l tending portion 18 in the manner shown is that, as the comminuting bodies 10 are thrown into the medial portion of the coarse grinding chamber 5, the larger of the bodies tend to roll further than the smaller, so that there is a classication of the comminuting bodies 10, resulting in grading the size of the comminuting bodiesin proportionfwith the size of the material being reduced. The shooting of the oversize mate-v rial into the medial portion of the grinding chamber ca uses'it to be further acted upon by the comminuting bodies before it can again pass through the plates 19.

rI he material delivered to the receptacle 17 may in some cases be derived from other sources than the coarse grinding chamber 5, and may also in some instances be classified in order to remove therefrom that portion which requires no further reduction. In the form of mill disclosed in Figs. 1, 2 and 3, all of the material Which is delivered from thev screen 14 is eventually returned to the mill by means of the revolving scoops 16. These scoops 16 during rotation of the mill, intermittently pick up batches of material from Within the receptacle 17 and deliver this material into the end of the finishing chamber 6 remote from the discharge end of the mill, through nozzles or injectors which have delivery7 passages so movable and directed that the material from Within the finishing chamber 6 will not return to the scoops 16. The portion of the mill in proximity to the division head 4 and the scoops 16 may be provided with a suitable removable vhousing or guard 24 as shown.v

This guard is made readilyv removable in order to permit access to the screen 14 and the scoops 16. The operation of the mill disclosed in Figs.v 1, 2 and 3 should be readily apparent from' the foreging description.

It Will be noted that the return scoops 16 may also be employed to inject other materials than that delivered from a preced ing stage ofthe mill, to the interior of the mill at any point intermediate its ends. In the diagram designated as Fig. 4, the scoops v16 are adapted to inject material to a mill of the two-stage or combination type from a trough 77, at a point intermediate the ends of' the finishing chamber 6. In this particular mill the division head 40 comprises a combined hol dbaclr and sizing screen 19 through Which the material discharged from the coarse grinding chamber 5 is delivered into the path of revolving elevating vanes 33 Which convey material thus elevated into the inletl end of the second stage or finishing chamber 6 through central discharge openings 35. When the material thus admitted to the finishing chamber 6 has been further reduced to a. sufficient extent.v it may be desirable to admit other matial to the mill from an outside source such as the trough 77 for the purpose of thoroughly mixing it with the comminuted material, and possibly also in order to pulverize said added material. The scoops 16 provide m'mple and efficient means for thus admitting additional material to the mill. Material thus added is intimately mixed with the charge Within the mill during its travel from the scoops 16 to the discharge trunnion 80. It will be understood of course that the mill disclosed in Fig. 4 should be provided with the usual discharge mechanism and with other details of construction necessary to complete the structure. The scoops 16 may be located at any desired point or points along the mill and may be utilized to intro# duce various materials into the mill.

Referring specifically to the material flow diagrams illustrated in Figs. 5 to 11 inclusive, it Will be noted that in each of these figures the material delivered Vfrom the first sizing screen 14 is discharged directly to a classifier 117 as indicated by the floivline 31. In the device illustrated in Fig. 5, the fine material which is separated from the oversize in the classifier 117 is finally discharged as indicated by the flow line 30. The oversize material is delivered into the finishing chamber 6 by means of the scoops 16 as indicated by the flow line 3:2. From the finishing chamber 6 the finally reduced material is delivered through the discharge trunnion 80, this finally reduced material in some cases requiring no further classification or reduction.

In the diagram designated as Fig. 6, the material passing through the screen 14 as indicated by the flow line 31 is mixed with the material delivered from the fine grinding chamber 6 through the discharge trunnion 8O as indicated by the return flow line 34. The mixture of materials is delivered -to the classifier 117 wherein the sufficiently comminuted material is separated from the oversize and the finished product is discharged as indicated by the flow line 30. The oversize material from the classifier 117 is returned to the mill and is delivered into the fine grinding chamber 6 for further reduction.' lVith this arrangement the product finally delivered as indicated by the flow line 30 will be exceedingly uniform since the classier 117 will also remove particles passing through the trunnion 80, which require further reduction.

In the diagram designated as Fig. 7 Athe material delivered from the sizing screen 14 as indicated by the flow line 31, passes directly to the Aclassifier 117 which separates the oversize from the material which has been sufficiently reduced, finally discharging the latter as indicated by the flow line 30. The oversize from the classifier 117 is returned to the mill and delivered into the 1 finishing chamber 6 by means of the scoops 16 as indicated by the flow line 32. After having been further reduced in the finishing chamber 6, the material is delivered from the mill through the discharge trunnion SO found .advantageous to apply the presenty and is mixed with the fine material delivered from Athe classifier 1 17 as indicated by the vflow line 34.

When reducing materials having certain characteristics or when exceedingly fine and unlform fina-l product 1s desired, it may be inventionv to mills having more than two grinding stages, as shown in Figs. 8 to `11 inclusive. In each of these diagrams, the mill is divided into vthree successive coniminuting chambers 5, 39,- Glvhaving comminuting bodies of graded' sizes therein.

While these figures disclose mills havingA three successive chambers, it willbe obvious that more'chambe'rs may beprovided `if desired, by merely inserting more division heads 4. .Y In the diagram. designated as Fig. 8, the material deliveredl from the coarse grinding chamber 5 past the first sizing screen 1 4 as indicated 'by the flow line 31,l passes directly vto the first classifier 117.- In the first classi vfier 117, the fine particles some ofwhicli may require further reduction, are separated from the larger particles, andare sent to the second classifier as 4indicated 'by the fiow line 3 0. The larger particles delivered from the first classifier 117 are'returne'd to-the mill and are introduced into the intermediatefgrinding chamber 39v by means of the first`set of scoops 16 vas indicated by the return flow.

line 32.A After having been further reduced in the intermediate sta e, the oversize from the rst classifier 117 is delivered past the second sizing screen 14 to the second classi fier 17 as indicated by the flow line 36. Thel finished product is delivered fr om the second classifier 117 as indicated by the flow line 38, while the oversizejfrom. this classi-v material delivered from the coarse grindingchamber 6 past `the first sizing screen 14 as indicated bythe fiow line I31', passesv directly to the single classifier 117. The

fine material discharged from the classifier 1-17 is sent directly to the finishing .chamber 6 as indicated -by the flow line 30, While the,

oversize from the classifier is sent'to the intermediate chamber-39 as indicated -by the fiow vline 32, for further reduction. The material delivered from the intermediate stage gast the second sizing screen 14 asindicate by the flow line 36, is mixed Withthe fine product delivered from the classifier 117,

and is likewise returned to the mill and delivered into the finishing chamber 6, for final reduction. The vfinished product is delivered from the chamber 6 through the discharge trunnion' 80.

In the diagram designated as Fig. 10,`the material delivered from the coarse grinding chamber 5 past the first sizing screen 14 as indicated by the fiow line 31, passes di'- rectly to the first classifier 117. 'In the first classifier 117, the finished product is se arated from the larger particles, and is. is-v.

charged as indicated by the flou'7 line 30.

The larger-particlesdelivered from the first classifier 117 are returned to the-mill and are introduced into the intermediate grinding chamber 39 for further reduction, by means of the first set of scoops 16 as indicated by the return fiowline 32. After having been further reduced in the intermediate stage, the oversize fromfthe first classifierV 117 is delivered past the second sizing screenv 14 to the secon classifier 117 as, indicated by the fiow line 36.v The finished product delivered from thelsecond classifier as indicated by the flow line 38, is mixed with the finished product-from the first classifier as indicated, While the oversize from the second classifier 117 is returned to the mill and is introduced into' the finishing I chamber 6 for final reduction, by means'of the second set of scoops 16 as indicated'by the return flow line 37 After being finally A comm'inuted in the finishing chamber 6, .the remaining material is delivered from the mill 'through the discharge trunnion 80 as indicated by the flow line 34, and is mixed with the finished product delivered from' the .two vclassifiers 117, as indicated. ,In thediagram designated as Fig. 11, the

material delivered from the coarse grinding chamber 5' past the first sizing screen 14 as indicated by the flow ,line 31, passes directly `to the first classifier 117. 4In the first {classifier 117, the relatively fine 'material yis separated from the larger particles, and

is'sent to the second classifier 117 as indil cated by the flow line 30. The larger particles delivered from the first classifier 117 are returnedv to the mill and are introduced into the intermediate grinding chamber 39 forfurther reduction by means of the first set of scoops'16 as indicated by the return flowline 32." After having been further reducedin theintermediate stage 39v thev oversize from the first classifieris de livered past the second sizing screen 14 to flow line 36. The large particles discharged from the second classifier 117 are returned the second classifier 117 as indicated by the' to thelmill and are introduced into the finishing chamber 6 forl final reduction, by means of the second set ofscoops 16 as indicated by the return fiow line 37. After having been further reduced inthe finishing chamber, 6, the remainingmaterial is delivered from the mill through the discharge trunnion 80 as indicated by the flow line 34, and is also sent to the second classifier 114. In the second classifier the finished ,product is separated from the material introduced thereto from the three sources indicatedV by the flow lines 30, 34, 36, and is delivered as indicated by the flow line 38.

lt Will be noted that by employing the systems Which have been graphically illus-' trated in Figs. 5 to 11 inclusive, as Well as others of a similar nature, materials havmill, and an external scoop movable with said drum to introduce material from said classifier directly into said drum remote from said end, a portion of said scoop extending transversely of the drum axisv and substantially parallel to the drum periphery.

4. In a comminuting mill, means dividing therrllitsuccessiverchambers, and means for automatically introducing material directly intmthe periphery of one of said chambers from an outside source at a point ing various characteristics may be redncednintermediate-the-endmoi chamber.

l be obvious that the eiiiciency of a mill constructed in accordance with the present invention, is increased to a maximum by removing the suihciently reduced product at one or more points along the mill. The provisionof suiiicient screening area at the discharge ends of the several chambers, permits rapid delivery of the materials from the chambers thereby producing a mill of large capacity; VThe screens llt'and scoops 16 are readily accessible being located outside of the shell 1. The mill is capable of operation either as a wet or dry mill without departure from the invention, and is of y exceedingly simple and compact internal construction.

It should be understood that it is not des' sired to limit the invention to the exact details of construction and of operation herein shown and described for various modifican tions Within they scope of the claims may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent: Y

l. ln a comminuting mill, a rotary drum, means forintroducing material into an end of said drum, and an external scoop movable vvith said drum to introduce material from an outside souce directly into said drum remote from said end, a portion of said scoop extending transversely of the drum axis and substantially parallel to the drum periphery.

2. in a comminuting'mill, a rotary drum,

means for introducing material into an end ci said drum, and an external scoop movable with said drum to introduce material from an outside source directly into said drum remote from said end, said scoo extending approximately halt1 Way aroun and substantially parallel to the drum periphery.

3. ln a comminuting mill, a rotary drum, means for introducin material into an end of said drum, a classi er independent of the 5. In a comminuting mill, means dividing v the mill into successivechambersfmeans-for delivering material ventirely free from a chamber at one Yside ofsaid dividing means, and means for VVintroducing said material directly into the periphery of another cham;

ber from an outside Ysource on the other side.AV

of said dividing means.

6. In a comminuting mill, means dividing the mill into successive chambers, a classiier independent of the mill, means for delivering material from the mill to said classier at one side of said dividing means,

and means for introducing material from" said classifier to the mill at the opposite side of said dividing means. f

7. In combination, a comminuting mill, means dividing the mill into successive chambers, means for delivering material from one of said chambers, and means for returning part of said material into the periphery of another of said chambers from a source independent of said mill at a point intermediate the ends of said latter chamber.

8. In a combination comminuting. mill, means dividing the mill into successive chambers, means for grading the material delivered from one of said chambers, said grading means being adapted to deliver the liner material free from the mill and to return the oversizeto said chamber, and an external scoop for returning said finer material into the periphery of another chamber of said mill from a source independent of said mill.

9. In a comminuting mill, a shell forming a chamber, ,a plurality of comminuting bodies in said chamber, a'screen in communication With said chamber, and acentral conveying projection having a tapered outer bounding surface and extending into said chamber for automatically classifying the comminuting bodies adjacent to said screen during operation of the mill.

l0. ln a comminuting mill, a shell and a division head forming a: chamber, a screen in said division head and in communication with said chamber, a plurality of comminuting bodies Within said chamber, and a central conveying projection having a peripherally smooth tapered outer bounding surface and extending into said chamber for automatically classifying the 'comminuting llC mill for grading materialpassing said iirst screen, means for returning the rejects from said second screen vto a medial portion of said chamber, and means for introducing thev material passing said secondscreen into a subsequent chamber of the mill.

12. In combination, a rotary drum having uniformdiameter throughout its length, a partition dividing said drum into a plurality of chambers, comminuting means in each of ysaid chambers, means connected with said partition delivering reduced material rompne'of said chambers, a stationary're-` ceptacle, adapted to receive said reduced material, and means connected with said drum for feeding material from said receptacle into another of said chambers. v

13: 'In'combination, a rotary mill compris. ing a drum `having uniform diameter throughout its length' and having comminuting means therein, means for removing material from a medial portion of said mill, a receptacle independent of said mill adapt-l edto receive reduced material, and means operable by said rotatingmill for returning material from said receptacle intoa medial portion of said drum.

14. In combination, a rotary mill having comminutingv means therein, means for re- -vmoving material from a medial portion of said mill, a receptacle independent of said mill adapted to receive reduced material, and an external peripheral scoop movable with said rotating mill for returning material from said receptacle into a medial portion of said mill.

15. In combination, a rotary mill having a partition forming a plurality of chambers, comminuting means in each of said chambers, means connected with said partition for delivering reduced material from one of said chambers, a stationary receptacle adapted to receive said reduced material, and means connected with said mill laterally of said partition for feeding material from' said receptacle into another of said chambers,

' 416. In combination, a rotary mill having comminutingmeans therein, means for removing material from a medial portion of said mill, a receptacle independent of said mill adapted to receive reduced material, and mea-ns operable by said'rotating mill for returning material fromv said receptacle into a medial portion of said mill located lat, erally of said material removing means.

17.' In combination, a rotary mill'having 'aplurality of comminuting chambers therein, means connected with said mill for dis- Acharging'reduced material from one of said chambers, a receptacle separate vfrom said mill for `receiving said reduced mateial, and means connected with said .mill for feeding material from said receptacle directly into anotherof said chambers.

18. In a comminuting mill, a shell forming a chamber, comminuting bodies in said chamber, a screen in communication with said chamber, and a central peripherally smoothconveying projection extending into said chamber coaxially with said mill for automatically classifying the comminuting bodies adjacent to said sc reen during operation of the mill. Y

19. In combination, a rotary mill having a partition forminga pluralitv o chambers,

comminuting ,means in each of saidchambers, means connected with'fsaid partition for delivering reduced material from one of said chambers, a stationary receptacle adapted to receive said reduced material, and a scoop connected with said mill but i11- dependent of said partition for Vfeeding ma terial from said receptacle into another vof` of said chambers.

'20. In a comminuting mill, arotary drum, means for introducingmaterial into an end of said drum, and a pair ofoppositely disposed external scoops movable with said drum to introduce material from an outside y source directly into dia-metrically oppositeV portions of said drum remote from said end, a portion'of each of said scoops extending transversely of the drum axis and substantially arallel to the drumperiphery.

21. n a comminuting mill, a rotary drum having uniform diameter throughout itsv lengt means for' introducing material into an en of said drum, and an external scoop movable' with said ldrum to introduce material from an outside source directly into said drum remote from said end, a portion of said scoop extending transversely of the drum axis and substantially parallel to the. drum periphery.

22. In a comminuting mill, means dividing the mill into successive chambers, a classifier independent of the mill, means for delivering material from the mill to said classifier at one side of said dividing means, and an external scoo for introducing material from said classifier to the mill at the opposite side of said dividing means.

23. In a comminuting mill, a rotary drum, means dividing said drum into successive chambers, a classifier independent of said drum but located in proximity. thereto, means for discharging material from one of said chambers to said classifier, and a scoop movable with said drum for introducing masaid chambers.

- 24. In a comminuting mill, a rotary drum, movable with said drum for returning a por a. partition dividing said drum into succestion of said material from said classifier to sive chambers, a classier independent `of a subsequent chamber of the mill. 3Q said mill located adjacentk to the periphery In testimony whereof, the signature of the 5 of said drum, mea-ns for delivering reduced inventor is axed hereto. materia-l from en initial chamber of'saidl drum to said classifier, and an external scoop RAY C. NEVSTHGUSE.

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