US1573191A - Pulverizing mill - Google Patents

Description

Feb. 16 1926.

F. I. RAYMOND ET AL- PULVERI ZING MILL Filed March' 18l l1925 6 Sheets-Sheet 5ta/[Rag .Semic/raar;

VW//fam il omeef Feb. 16 1926. F. RAYMOND ET AL PULVERIZING MILL Sheets-Sht 5 l en/ffl WI//dm fw @www F. l. RAYMOND ET AL PULVERIZING MILL 6 Sheets-Sheet A4 Filed March 18, 1925 Feb. 16 1926.

F. l. RAYMOND n Al.

PULVERI ZING MILL Filed March 18l 1925 6 Sheets-Sheet 6 frnfe ors Patented Feb. 16, 192%.

PATENT OFFICE.

FRED I. RAYMOND, OF EVANSTON, ILLINOIS, .ANID` WILLIAM B. SENSEHAN, OF LOS y ANGELES, CALIFORNIA, ASSIGNORS TO THE RAYMOND BROTHERS IMPACT PUL- VEBIZER COMPANY, F CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PULVERIZING MILL.

Application' filed March 18, 1925. Serial No. 16,543.

To all whom 'it may concern.:

Be it known that we, FRED I. RAYMOND and WILLIAM B. SENSEMAN, citizens of the United States, residing at Evanston, in the l county vof Cook and State of Illinois, and Los'ngeles,u in the county of Los Angeles and State of California, respectively, have invented certainnew'and useful Improve-' 204 travel with the rollers and close to the bottom of the mill so as to pick up the material which drops below the region in which the pulverization takes place, air being introduced into the mill at the bottom and withdrawn from the mill at the top carrying with it such material as .has been sufficiently pulverzed.

The primary object of the inventiony is to provide certain im rovements in a mill of 3o this type calculate to increase the capacity of the mill, insure more uniform pulverization of the material treated and strengthen the arts of the mill that are particularly subject to stress.

The improvements comprise:

bottom or bate member of the mill casing whereb said orts are less likely to be fclogge with t e lmaterial treated, this ari rangement making it possible to increase the size and lhence the capacity of the mill;

a novel construction and arran ement of the plows` which increases Atheir e ciency; new

f and improved means 'for feeding the material into the mill so that` it is brought in divided charges close to the bull ring; an improved form of air trunk for equalizing the volume of air introduced Athrough the several air ports; and novel and im roved means for taking the end thrust of t e cencertain changes in the -air inlet ports and in the tral drivin shaft and su ortin the ear which drivegs said shaft. ppg g The invention is illustrated in the accompanying drawings in a preferred embodiment including all ofthe features of improvement above mentioned. It will be understood, however, that the invention is not to be considered as limited to the em loyment of all,.of these features in com ination in a single installation.

Referring to the drawings,

Fig. 1 is a fragmentary side elevation of a pulverizing mill constructed in accordance with this invention, parts of the mill being broken awav and parts shown in section. f

Fig. 2 is a vertical sectional view of the lower portion ofthe mill.

Fig. 3 is a sectional plan on line 3 3 of Fig. 2.

Fig. 4 is a sectional plan on the broken line designated 1 -4 of Fig. 2.

Fig. 5vis a fragmentary 4sectional elevation taken on line 5-5 of Fig. 3.

Fig. 6 is al view, in perspective, of the base casting of the mill.

Fig. 7 is a side elevation, of one of the plows and associated parts.

Fig. 8 is a plan view` of the parts shown in Fig. 7 t 80 Flg. 9 is a sectional view on line 9-9 of Fig. ,and p Figs. 10 and 11 are sectional views-on lines 10-10 and 11-11 of Fig. 8.

Referring to the drawings, 10 desi ates the base or bottom member of the mill, 11 and annular member, 12 webs which support the annular member 11 on the base member 10 (these three members beinrr preferably cast integral) with the we s arranged to provide air inlet ports 13 leading to the interior of the mill. 14 is the upper casing of the mill and 15 an outlet .pipe which is ordinarily connected with an exhaust fan (not shown). 16 designates a 9 5 circular air trunk enclosing the air ports and supplied with air vthrough a pipe 17 which, in the ordinary installation, is connected with the separating device into which the pulvcized material is drawn by action 10 auf .a shaft 27 of the exhaust fan. ln a pulverizing and separating system of this sort pipe 15 is on the suction side of the exhaust fan and pipe 17 on the pressure side although the pres- .:sure may be a trifle less than atmospheric pressure so that these terms are used in a relative sense. Annular member 11, above referred to, supports an annular, iixed pulverizing member or bull ring 18 against which operate a number of pulverizing rol- 1ers 19 revolubly supported by members 2() pivoted from a structure 21 'which is iixed to the upper end of the main driven shaft 22 of the mill. A plurnlityof plows 23 are supported so as to. revolve with the rollers. The plows' pick up the material falling to the bottom of the mill and deliver the same to the bull ring in advance of the rollers, the arrangement contemplating a plow for each roller. The roller carrying structure 21 and .the driven shaft 22 are supported upon a central pedestal 24 through Which the shaft extends, this pedestal being formed at the bottom wih a flange 25 which constitutes a part of the bottom of the mill, being secured to bottom member 10 by bolts 26 (Fig. 2). The shaft 22 is driven from provided with a belt pulley 28 (Fig. 1) through a reducing bevel gearing ,consisting of bevel pinion 29 on shaft27 and bevel gear 30 on shaft 22.

The general construction and operation of the mill will be understood from the foregoing description.

While the improvements with which thls invention is concerned are applicable to mills .of different sizes, the invention has in contemplation particularly a mill considerably larger than mills 'of this type heretoore constructed. With the diameter of the mill and the number of its rollers increased the volume of air passing through the mill will have to be increased proportionately. rlhis involves a diiiiculty since there is a practical limit to the distance that material in the bottom of a mill of this type can be raised by plows in order to bring it into the region of pulverization, and consequently a limit to the vertical dimensions of the air inlet ports. In mills of this type as heretofore constructed there has always been` some clogging of the air ports. Some of the mater1al scooped up by the lows is forced into the air ports so that t e edective size of the ports when the machine is in operation is less than their actual size. Our present invention provides certain new and improved constructions. and arrangements whereby the ports are kept free from obstruction. ln the iirst place, the bottom surfaces of the air ports are sloped inwardly and downwardly, as indicated at 31. Preferably the bottom surface 16El of the air trunk 16 is also sloped downward toward the Lair lports so that this surface tende by bolts 40, the wedge to be self cleaning. In the second place, the plows are arranged so. that they travel over a circular path at some distance within the inner ends of the air ports, this portion 'of the bottom member 10 being also preferably inclined, as indicated at 32, and the surface33 intervening between the plows and the air ports, which surface is also inclined downwardly and inwardly, maybe given a sharper pitch than surfaces 31 and 32. Surfaces 32 and 33 may, however, have the same slope. In either case any material which is forced outwardly by the plows or which spills over the outer edges of the plows will fall, in a great measure at least, upon the more or less steeply inclined surface 33 and slide back into the path of the plows. If any material drifts into the air ports' or even into the air trunk 16 it will also tend, because of the inclination of the bottom surfaces of such ports and trunk, to slide by gravity back into the mill., The upper surface 34 of flange 25 of the pedestal casting 24 is also givenl a sharp pitch so that the material treated will not readily lodge on this part of the vbottom of the mill.

The 'webs 12 are arranged obliquely to the radial lines of the mill, as indicated in Figs. 3 and 4, and are formed so that the inner portions 35 of the air ports are of substantially uniform cross section while the outer portions or mouths 36 of the air ports are flared outwardly. The webs 12 are designed so that besides deiiecting the air and dividing the air current passing through trunk 16 and causing it to enter the mill in approximately tangential streams, they serve to material strengthen the base casting of the mill against the thrust of the rollers on the bull ring, and this is a 'consideration of some importance in a large mill. 'lhe annular portion l1 of the base casting 1s of smaller diameter than the bot tom member 10 thereof and the web 12 arel frmed'so that they project diagonally from theannular member downwardly 'and out-- wardly to the edge of the bottom member, as indicated at 37, forming, in effect, buttresses transmitting the thrusts against the bull ring obliquely to and against the heavy bottom member of the casting. The bull ring 18 lhas a wedging lit with the annular member 11 and is kept in place by aA plu' rality of wedge blocks 38 arranged between the upper surface of the bull ring and a ring 39 secured to the annular member 11 blocks 38 being drawn back byl bolts 41 passing through member 11. The upper casing 14 is secured by bolts 42 to a Vflange 43 on the ring 39.

The webs 12 preferably have the following configuration: One side face 44 of each -web lies in a single plane which, besides being oblique with respect to a radial line of the mill, slants forwardly and upward- 1,57aie1 Q ly in the direction toward the air current passing through trunk 16. angle between this face 44 and the surfaces 31 and 33 is preferably slightly less, but in any case, not greater. than a right angle. The other side of the web is formed with two surfaces making an obtuse angle to each other, the inner surface 45 vbeing parallel with the surface 44 of the adjacentv web while the surface 46 slants away from the surface 44l of the adjacent web in the direction toward the outer edge of the bottom member, thereby providing the liared mouth for the intervening air inlet port as above mentioned. The air passing through the trunk 16 will, therefore, impinge upon the surfaces 44 and be crowded through the narrowed inner ends of the air ports (narrowed both vertically and laterally) in streams which tend to kee the air ports cleared of loose material. he rojections of the webs beyond annular mem er 11 consequently serve two purposes, namely, to strengthen the base casting against the thrusts of the rollers on the bull ring, and to deflect air from the circular trunk into the air ports. It will be observed that the inner edgesof the webs 12 are substantially-normal to the surface 33 so that a free space Vis left between the webs and the path. of the plows which, as stated, travel over the Vsurface 32.

In order to insure an equal distribution of air to the several air ports, the trunk 16 is preferably constructed as shown in Figs. 1 and 2. That is, the height of the trunk diminishes' circumferent-ially of the mill beginning at the point where the air .enters the drum through pipe 17. Pipe 17 is shown as enterng the 4trunk laterally at the point 47 of\ the trunk. From this point the trunk gradually diminishes in height around the mill in the direction of the flow of the air to the lowest point 48 which is 'ust under the elbow 49 thatconnects pipe 1 with the trunk. The trunk is shown as consisting of a sheet metal structure secured by its flange 50 to the bottom member l() and by a circular angle iron 51 to` the annular member 11. j

The equal distribution of air to the air 1nlet ports, the projection of the webs 12 into Vthe air trunk, the forward pitch of the side faces ofthe webs against which the air impinges, thedownward slope of the bottoms of the air ports andd the sharp pitch of the inner ends of said bottoms and of the surface intervening between the air ports and the plows and the downward inclination of the bottom .of the air trunk are all features which contribute toward keeping the a`r ports clear of material. With the air ports clear the capacity of the mill is increased; or what amounts to the same thing,

with air ports of the same aggregate cross' The dihedral sectional area, the mill may be built on a larger scale with an increased number of rollers since with less obstruction to the ports a larger volume of air can be circulated through the apparatus proportioned to the larger amount of material pulverized.

The plows, which have been designated generally by the numerals 23, are secured to a sloping flange or circular apron 52 at the bottom of a sleeve 53, the 'ange 54 of which is secured to a flange 55 on the roller carrier 21. The apron 52 is formed with in clined peripheral projections 56 cast integrally with the apron, the body of which adjacent these projections is thickened as indicated at 57 (Figs. 8 and 10). The body 58 of the plow, in each case, is secured to the projection 56 by bolts 59, the plow body being formed on the under side with a recess 60 to fit over a ribv 61 on projection 56. Each plow is provided with a removable, hard steel share 62 secured to the body of the plow zby screws 63 passing through flanges64' and 65 on the plow body and share, respectively, flange 65 intervening between flange 64 and the forward ed e of the plow supporting projection 56 as siown in Fig. 11. The plow has a curved rib 66 at its outer edge and a.short rib 67 at the upper end of its inner edge. It will be observed that the plow projects considerably' below -the outer edge of apron 52 so that any material sliding'over upon the plow from the apron reaches the plow nearly half way toward its upper end. There is, therefore, less chance for material to be crowded over the edge of the plow than if, as in prior constructions', the lower edge of the plow was substantially at the level of the lower edge of the apron.

As a preferred but optional feature, the invention provides for feeding the material entering the mill to the rollers separately in divided charges. "We have shown a main feed chute 68 which enters the top of casing 14 and may be provided with any suitable measuring device, not shown. The chute delivers the material into the mill above the roller carrying structure 21 and at one side of the end of shaft 22. The roller journal housings 20 are pivoted at 69 to forked arms 70 on the carrier 21. Between each pair of arms is an opening 71 and from these openings lead chutes 72 eX- v shaft of the mill and the bevel gear keyed thereon. Arranged below the bevel gear 3() is a thrust bearincr comprising a casing 74C, ball races 75 and $6 and balls 77. The upper raceway 76 carries a plate 78 wliich bears aga-inst and revolves with theA shaft and bevel gear and with the upper raceway. rlfhe bottom of casing Z4 is provided with a socket 79 adapted to receive a ball 80 on the end of an adjusting screw 8l threaded into a member 82, screw 8l and member 82 forming together an adjustable strut and member 82 being formed on its lower end with a. ball 83 supported in a socket 84 formed in a plate 85 secured tothe foundation 86. v

'lhe devices just described provide for taking ,some of the end thrust of shaft 22 while permitting the shaft to deflect late rally, to a certain extent, as may happen in the operation ofthe mill. The bevel gear 30 is supported on the same device.

`While we have described our invention in certain preferred embodiments, it 1s recognized that modifications may be made without departure from the -principles of the invention. The intention isto cover all novel features of the mill both broadly and specifically, singly and in combination, within the scope of the appended claims.

We claim: n l j 1. A pulverizing mill comprising a bull ring,.iollers operating lagainst the saine, air

ports below the bull ring and plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, the bottom of the mill between said air ports and plows having a downwardly inclined surface toward the plows and extending under said plows.

2. A pulverizing mill comprising a bull ring, rollers operating against the same, air ports below the -biill ring, and plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, the bottom surfaces of the air. inlet ports being inclined downwardly and inwai" ly with a greater inclination at the inner than at the outer ends of the ports.v

8. A pulverizing mill comprising va bull ring, rollers operating against the same. air ports below the bull ring, and plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, the bottom surfaces of the air inlet ports being incinefl downwardly and inwardly and the bottom of the mill between said air ports and plows having a downward pitch in the direction toward the plows and extending under said plows.

4. A pulverizing mill comprising a bull ring, rollers operating against the same, air ports below the bull ring, and plows having rotary movement over the bottom of ports below the bull ring, and

`wardly and the bottom interior the mill to deliver material between the rollers and bull ring, the bottom surfaces of the air inlet ports being inclined downwardly and inwardly kand the bottom of the mill between said air ports and plows having a downward pitch inthe direction toward the plows of greater inclination than the bottoms of the air ports.

5. A pulverizing mill comprising a bull ring, rollers operating against the same, air ports belowl the bull ring, and plows having rotary movement over the bottom of the mill to deliver material between the lrollers and bull ring, the bottom of the mill being formed with an inwardly and downwardly inclined surface over which the plows travel and with an inwardly and downwardly inclined surface between the plows and the airinlet ports.

6. A pulverizing mill comprising a bull ring, rollers operating against the same, air plows having rotary movement over the bottom of the mill 1 to deliver material between the rollers and bull ring, the bottom of the mill being formed with an inwardly and downwardly inclined surface over which the plows travel and with an inwardly and downwardly inclined surface between the plows and the air inlet ports of steeper pitch than the pitch of said first named surface. 7. A pulverizing mill ring, rollers operating against the same, air ports below the bull ring, and plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, the bottom surfaces of theair inlet ports being inclined downwardly and inwardly' and the bottom surface of the mill being formed with an inwardly and downwardly inclined surface over which the plows move and with an inwardly and downwardly inclined `surface between said plows and air inlets.

A pulverizing mill comprising a. bull ring, rollers operating against the saine, air ports below the bull ring, and plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, the bottom surfaces of the air inlet ports being inclined downwardly and insurface of the mill being formed with an inwardly and downcomprising a bull y wardly 'inclined surface over which the' and plows which travel over said inclined bottom member and operate to deliver material into the path of the rollers.

10. In a pulverizing mill, a bottom member, the upper surface of which is inclined inwardly and downwardly, :1n-annular member, rollers which operate within and against said annular-member, webs supporting said annular member on the bottom member spaced to provide a plurality ofA air ports which are oblique with respect to radii of the mill, and plows which travel over said inclined bottom member and operate to deliver material into the `path of the rollers.

11. In a pulverizing mill, a bottom member, the upper surface of which is inclined inwardly and downwardly, an annular member, rollers which operate within and against said annular member, plows which travel over said bottom member and operate to deliver material into the path of the rollers, and webs 'supporting said annular member on the bottom member and spaced to Jform air ports oblique to the radii of the mill, one side surface of each of said webs lying in a single plane, and the other side having an inwardly placed surface substantially parallel to the opposite side of the adjacentweb and an outer surface which, diverges outwardly with respectto' the opposlte side of said other web.

12. In'a pulverizing mill, a bottom member, the upper surface of which .is inclined inwardly and downwardly, an annular member, rollers which o erate within and against said annular mem er, plows which travel over said bottom member and operate to deliver material into the path of the rollers, and webs supporting said annular member on thel bottom member and spaced to form air ports oblique to the radii of the mill, one

side surface of each of said webs lying in a single plane having a forward pltch from bottom to top in the direction of the movement of air toward said air port which it bounds on oneside, and the other side having an inwardly 'placed surface parallel to the opposite side of the ad]acent web and an outer surface diverging outwardly from the opposite side of said other web.

13. In a pulverizing mill, a bottom member, 'an annular member, rollers operating within and against the annular member, plows which travel over the .bottom member and operate to deliver material into the path ot the rollers, webs supporting said annular member on the bottom member spaced to form air ports oblique to the radii of the mill, a circular air trunk surroundmg said air ports, said webs pro]ect1ng`1nto said air trunk so as to deiiect air therefrom through the air ports` l l 14. A ulverizing mill formed with a plurality o air ports oblique with respect to the radial lines of the mill, and a circular air trunk surrounding said mill and enclosing the air ports, said air ports being formed by spaced webs which project into the air trunk so as to deflect air therefrom through the ports.

15. In a pulverizing mill, a bottom member, an annular member of smaller diameter than the bottom member, a plurality of rollers operating within and against the annular member, and webs supporting the annular member on the bottom member spaced to provide air inlet ports, the webs extending outwardly and downwardly from the annular member to said bottom member.

16. In a pulverizing mill, a bottom member,an annular member of smaller diameter than the bottom member, a plurality of rollers operating within and against the annular member, and webs supporting the annular member on the bottom member spaced to provide air inlet ports, the webs extending outwardly and downwardly from the annular member to said bottom member, the inner portions of the webs being spaced apart in parallelism and the outer portions being formed so that outwardly iiaring mouths are provided for the air inlet ports.

17. In a pulverizing mill, a bottom member, an annular member of smaller diameter than the bottom member, a plurality of roll- 9 5 ers operating within and against the annular member, plows which travel over the bottom member and operate to feed material into the path of the rollers, and webs supporting the annular member on the bottom member spaced to provide air inlet ports, the webs extending outwardly and downwardly from the annular member to the bottom member, the upper surface of the b'ottom member being inclined downwardly and inwardly. 1

18. In a pulverizing mill, a bottom member, an annular member of smaller diameter than thebottom member, a plurality of rollers operating within and against the annular member, webs supporting the annular member on the bottom member s aced to provide air inlet ports and exten ing outwardly beyond the annular member, and plows which travel over the bottom member at a substantialdistance from the inner ends of said webs, the surface of the bottom member between said web s and plows having a downward and inward inclination.

19. In a pulverizing mill, a bottom member, an annular member of smaller diameter than the bottom member, a plurality of rollers operating within and against the annular member, -webs supporting the annular member on the bottom member s aced to ends of saidlwebs, the surface ofthe bottom member between said webs and plows having a downward and inward inclination, the surfaces thereof over which the plows travel and within the air ports being also inclined inwardly and downwardly but with a pitch which is less than the pitch of the intervenl ing surface.

20. ln combination with the 'rollers of a pulveriaing mill, an integral base casting consisting of a bottom member, `an annular member of smaller diameter lthan 'the bottom member, and webs between said members spaced to form air inlet ports and extending downwardly and outwardly from the annular member to the bottom member so as to buttress the former against the latter.

21. In combination with the rollers of a pulverizing mill, an integral base casting consisting of a bottom member the upper surface of which has an inclination inwardly and downwardly, an annular member of smaller diameter than the bottom member, and webs between said members spaced to,l form air inlet ports and extending downwardly and outwardly from the annular member to the bottom member so` as to buttress the former against the latter.

22. ln a pulverizing mill, a bottom member, an annular member of smaller diameter than the bottom member, a plurality of rollers operating within and against the annular member, webs supportingv theannular member on the bottom member spaced to provide air inlet ports and extending outwardly beyond the annular member to provide enlarged entrance openings to 'the air ports, and a circular air trunk surrounding vthe millfwith which said openings communicate.

23. ln a pulverizing mill, a bottom member, an annular member of smaller diameter than the bottom member, a plurality of rollers operating within and againstthe .annularmember, webs supporting the annular member on the bottom member spaced to provide air inlet ports and extending outwardly beyond the annular ymember to provide enlarged entrance openings to the air ports, and a circular air'trunk surrounding the mill with which said openings communicate, the inner spaced apart in parallelism with Veach other, and the outer portions being formed so that outwardly flaring mouths are provided for the air inlet ports.

24. In a pul-verzing mill, a bottom member, an annular member of smaller diameter than the bottom member, a plurality of rollers operating within and against the annular member, web s supporting the annular member on the bottom member spaced to provide air inlet ports and extending outwardly beyond the annular member to provide enlarged entrance openings to the air ports, a circularair trunk surrounding the portions of said webs being mill with which said openings communicate,

the inner portions of said webs being spaced the place of greatest cross sectional area.

25. In a pul'verizing mill, a, bottom member, an annular member of smaller diameter than the bottom member, a plurality of rollers operating within and against the annular member, webs supporting the annular member on the bottoml member spaced to provide air inlet ports and extending outwardly beyond the annular member, and a circular air trunk surrounding the mill so as to close said air ports, each of said webs being formed with a side surface oblique with respect to the radiusr` of the mill and pitched forwardly, from bottom to top, in the direction from which the air flows in passing through said trunk.

26. In a pulverizing mill, a bottom member, an annular member of smaller diameter thanthe bottom member,` a plurality of rollers operating within and against the annular member, webs supporting the annular member on the bottom member spaced to provide air inlet ports and extending outcircular air trunk surrounding the mill so as to close said air ports, each of said webs being formed with a side surface oblique with respect to the radius of the mill and pitched forwardly, from bottom to top, in the direction from which the air flows in passing through said trunk, the opposite side of the adjacent web'being formed with an inwardly placed surface parallel to the first mentioned surface and at the outer end of the web a surface vwhich diverges from said rst mentioned surface in the direction of the incoming air. 27. In a pulver-izing mill of the type dcscribed, a bull ring, a plurality of rollers operating thereagainst, and supporting means for the bull ring inclined outwardly and downwardly from the bull ring and designed to form a. plurality of air linlet ports having comparatively large entrance openings positioned outwardly beyond the bull ring and comparatively small discharge ports beneath the bull ring. 28. In a pulverizing mill, the combination of abase member provided with a bull ring and formed'with air inlet ports under the bull ring, rollers lwhich operate against the bull ring, plows which operate to deliver wardly beyond the annular member, and a its material into the path of the rollers, a cir rollers,

.of a mill casing, u

4wardly so that of plows perlpherally arranged on the apron Iso as to project downwardly from the edge of the apron to points adjacent the bottom of the casing and upwardly therefrom to points adjacent the bull ring.

30. In a pulverizing mill, the combination ble shaft vsupporting said rollers, a revo ly 1nrollers, avdownwardly' and outward clined apron onsaid shaft, theV bottom of the mill being inclined downwardly and inthe outer edgeof the apron is a substantial distance above the bottom of the mill casing, and a plurality of plows peripherally arranged on the apron so as to project downwardly from the edge of the apron to v'points of the mill casing and upwardly therefrom to points adjacent the bull ring.

31. In a pulverizingmill, the combination of a mill casing, a bull ring,l a plurality of a revoluble shaft supporting said rollers, av downwardly and outwardly inclined Vapron on said shaft, obliquely arranged peripheral projections onsaid apron, and plows secured to said projections so as to extend downwardly toward the bottom of the mill casing and upwardly toward the bull ring. l

32. In a pulverizing mill, the combination of a mill casing. a bull ring, a plurality of rollers, a revoluble shaft support-ing said rollers, a downwardly and outwardly inf clined apron on said shaft, said apron having obliquely inclined projections extending beyond its outer edge, and similarly inclined plows secured to said projections and positioned entirely beyond the peripheral edge of the apron, the lower` edge of each f plow extending below the' apron and the upper end extending above the apron.

33. In a pulverizing mill, a bottom member, the inner portion o f which is inclined outwardly and downwardly, and the outer portion of which is inclinedinwardly and downwardly, an annular member. rollers which operate within and against the annular member, webs.. supporting said annular member from the bottom and spaced apart to provide air inlet ports, and plows which travel over the inwardly and downwardly, extending portion of the bottom to deliver material into the path of the rollers.

34. In a pulverizing mill, a bottom memand a plurality a bull ring, a plurality of adjacent the bottomber, the inner portion of which is inclined outwardly and downwardly, and the outer` portion of which is inclined inwardly and downwardly, an annular member, rollers which operate within and against the annular member, a revoluble shaft supporting the rollers, webs supporting said annular member from the bottom and spaced apart to provide a'ir inlet port-s, an apron supported by the shaft and inclined outwardly and downwardly above the correspondingly inclined portion of the bottom and plows 4carried by the apron and operating over the inwardly and downwardly inclined portion of the bottom to deliver material into the path of the rollers.

35.y In combination with a bull ring, pulverizingrollers and plows of a pulverizing mill of the type described, means constituting a plurality of air inlet ports entering the mill obliquely below the bull ring, the openings into which are flared outwardly,'said means comprising webs which project outwardly beyond the portion of the wall above said openings.

36. In combinationiwith a bull ring, pulverizing rollers and plows of a pulverizing mill of the t-ype described, means constituting a plurality of air inlet ports entering the mill obliquely below the bull ring, said means comprising .webs having surfaces pitched forwardly from bottom to top t0- ward the air entering said openings, respectively.

37. In combination with a bull ring, pulverizing rollers and plows of a pulverizing .mill of the type described` means constituting a plurality yof air inlet ports entering the mill obliquely below the bull ring, a portion of the bottom of said mill being inclined downwardly beyond the inlet ports inlhe direct-ion toward the center of the m1 38. In combination with a bull ring, pulverizing rollers andplows of a pulverizing mill of the type described. means constitut ing a plurality of air inlet ports entering the mill obliquely below the bull ring, a portion of the bottom of said mill being inclined downwardly7 in the direction toward the center of the mill, and said plows arranged to travel over the inclined bottom of the mill at a substantial distance from the inner ends of the air ports.

39. In combination with a bull ring, pulverizing rollers and plows of a pulverizing` lmill ofthe tvpe described. means constitu ing'a -plurality of air inlet ports entering the mill obliquelyT below the bull ring` a portion of the bottom ot clined downwardly in the'direction toward the center of Vthe mill land saidplows'arranged to travel over the inclined bottom'o'f" the mill at a substantial distance from the said mill being in.V

portion beneath the plows,

vinner edges of said webs being inner ends of the air ports, the portion of the bottom of the mill between said plows and air ports having a greater pitch than the surfaces ofthe bottom on opposite sides of it.

40. In combination with a bull ring, puln verizing rollers and plows of a pulverizing mill of the type described, means coiistituting a plurality of air inlet ports entering the mill obliquely below the bull ring, a portion of the botton'rot said mill, including the lower surfaces of said air ports, and the being inclined downwardly in a direction toward the Center of the mill.

4l. In combination with the bull ring. pulyerizing rollers and plows of a pulverizing mill of the type described, means constituting a plurality of air inlet ports entering the mill obliquely below the bull ring, said means comprising webs which project outwardly beyond the portion of the wall above the entrance openings to said inlet ports and formed so that the outer porti-ons of the openings are flared and having surfaces pitched forwardly from bottom to top toward the air entering said openings, respectively, a portion of the inclined bottom of said mill including the lower surfaces of said air ports being inclined downwardly in a direction toward the center of the mill land the plows being arranged .so as to travel over the bottom of the mill at a substantial distance from the inner ends of said air ports.

4Q. A pulverizing mill comprising a bull ring, rollers operating against the same, air ports below the bull ring, and plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, the bottom surfaces-of the air inlet ports being inclined downwardly and inwardly with a greater inclination at the inner than at the outer ends of the and the bottom of the mill within said air ports having a surface of substantially the same inclination as the bottoms of the airv ports at their inner ends.

43'. 1n a pulverizing mill, a bottom member, a portion of theV upper surface of which is inclined inwardly and downwardly, anl annuar member, rollers which operate within and against said annular member, webs supporting said annular member on the bottom member spaced to provide a plurality of air ports, and plows which travel over said inclined bottom member and operate to deliver material into the path of 'the rollers, the substantially normal to the adjacent inclined upper surface of the bottom member leaving an unobstructed space between the ends of the webs and the plows.

44. In a pulverizingmill, a bottom member, the upper surface of which 1s inclined inwardly and downwardly, an annular member,.rollers which operate within and against ports,-

maaier said annular member, plows which travel over said bottom member and operate to deliver material into the path of the rollers, and webs supporting said annular member on the bottom member and spaced to form air ports oblique to the radii of the mill, one side surface of each of said webs lying in a single plane, t-lie dihedral angle between which and the upper surface of the bottom member being not greater than a right angle, and the other side having an inwardly placed surface substantially parallel toy the opposite side of the adjacent web and an outer surface which diverges outwardly with respect to the opposite side of said other web.

45. In a pulverizing mill, a bottom member, the upper surface of which is inclined inwardly and downwardly, an annular ineinber, rollers which operate within and against said annular member, plows which travel o ver said bottom member and operate to deliver material into the path of. the rollers, and webs supporting said annular member on the bottom member and spaced to form air' ports oblique to the radii of the mill, one side surface of each of said webs lying in a single plane, the dihedral angle between which and the upper surface of the bottom member being not and the other side having an inwardly ,placedv surface substantiallyfparallel to the opposite side of the adjacent web and an outer surface which diverges outwardly with respect to the opposite side of said other web, the bottom surfaces of the air ports having an inclination at their inner ends greater than at their outer ends and the upper surfaces of said ports being substantially parallel to the inner ends of the bottom surfaces.l

46. '1n a pnlverizing mill, a bottom member, an annular member, 'rollers which op-` erate within and against the annular member, plows which travel over the bottom member and operate to deliver material to the path of the rollers, and webs `between said bottom member and annular member spaced to provide a plurality ofair ports oblique to the radii ot' the mill. said ports having greater lateral and yvertical dimensions at their outer ends than at their inner ends.

47. In a pulverizing mill, a bottom memgreater than a right angle.

ber, an annular member, rollers which operate within and against the annular member, plows which travel over the bottom member and operate to deliver material to the path of, the rollers, and webs between said bottom member and annular member spaced to provide a plurality of air ports oblique to the radii of the mill, said ports having greater lateral and vertical dimensions at their 'outer ends than at their inner ends, and the bottom member of the mill within said downwardly toward the center.

ports having a surface inclined H30 48. In a pulverizing mill, a bottom meinber, an annular member, rollers which operate within and against the annular member, plows which travel over the bottom member and operate to deliver material to the path of the rollers, and webs between said bottom member and annular member spaced to provide a plurality of air ports oblique to the radii of the mill, said ports having greater lateral and vertical dimensions 'at their outer ends than at their inner ends,`and the bottom member of the mill within said portshavi'ng a surface inclined downwardly toward the center, the inclination of `which is substantially the same as the inclination of the inner portions of the bottom surfaces of the air ports.

49. In a pulverizing mill, a bottom member, an annular member of smaller diameter than the bottom member, a plurality of rollers operating within and against the annular member, and webs supporting said annular member on, the bottom member spaced to provide air inlet ports, which webs project upwardly on the outer surface of the annular member and extend downwardly and outwardly to the bottom member.

50. In a pulverizing mill, the combination of a bull ring, rollers operative against the same, air ports below the bull ring, plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, and an air trunk surrounding the mill which supplies air to the air ports, the bottom surface of the mill and of said'air trunk being inclined downwardly toward the center of the mill.

51. In a pulverizing mill, the combination of a bull ring, rollers operative against the same, air ports below the bull ring, plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, and an air trunk surrounding the mill which supplies air to the air ports, the bottom surfaces of the air'trunk, of the air ports and of the mill within said air ports being inclined downwardly toward the cente;` of the mill.

52. In a pulverizing mill, the combination of a bull ring, rollers operative against the ports same, air ports below the bull ring, plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, and an air trunk surrounding` the .mill which supplies air to the air ports, the bottom surfaces of the air trunk, of the air ports and of the mill between said air ports and plows and under said plows being inclined downwardly toward the center of the mill.

53. A pulverizing mill comprising a bull ring, rollers operating against the same, air below the bull ring and plows having rotary movement over the `bottom of the mill to deliver material between the rollers and bull ring, the bottom surface of the mill and of the air ports being inclined down wardly toward the center of the mill and the upper surfaces of the air ports being substantially parallel with the bottom surfaces thereof at the inner ends of the ports.

54. A pulverizing mill comprising a bull ring, rollers operating against the same, air ports belowlthe bull ring and plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, the bottom surfaces of the mill and the inner portions of the bottom surfaces of the air ports having substantially the same inclination downwardly toward the center of the mill, the outer portions of said bottom surfaces of the air ports being also inclined downwardly but at a lesser angle.

55. A 'pulverizing mill comprising a bull ring, rollers operating against the same, air ports below the bull ring and plows having rotary movement over the bottom of the mill to deliver material between the rollers and bull ring, the bottom surfaces of the mill and the inner portions of the bottom surfaces of the air ports having substantially the same inclination downwardly toward the center of the mill, the outer portions of said bottom surfaces of the' air ports being also inclined downwardly but at a lesser angle, and the upper surfaces of the air ports being substantially parallel with the inner portions of the bottom surfaces.

FRED I. RAYMGN. 'WHJLIAM SENSEMAN.

Certincate oit @lorreeti'ion0 It is hereby 'certified that in Letters Patent No. 1,573,191, granted February 16,

1926, upon the application of Fred I.

Raymon d, of Evanston, Illinois, B. Senseman, of Los Angeles, California, for an im and `William roveinent iii Pulverizing Mills, errors appear in the printed specification requiring correction as follows:

Page 1, line 33, for the word arts read materially; page mda/ned; page 8,

read parte; page 2', line 103 for 4, line 57, claim 3, for the misspelled word inciiied read line 27, claim 4l, strike out the same before the word bottom in line E material word inclined and insert the 2, same claim; and that the said Letters Patent should be read with these corrections therein that the saine may conform to the i'ecord of the case in the Patent Oilice.

Signed and sealed this 30th day of March, A. D. 1926.

[SEAL] M. J. Moons,

rioting Commissioner of Patents.

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