US2051489A - Separator device for roughage mills - Google Patents

Description

Aug. 18, 1936. J. HOLLAND-LETZ SEPARATOR DEVICE FOR ROUGHAGE'MILLS Filed May 18, 1951 5 Sheets-Sheet 1 INVENTOR. Jaim bZZand-Le Z'Z A TTORNE Y.

Aug. 18, 1936. J. HOLLAND-LETZ SEPARATOR DEVICE FOR ROUGHAGE MILLS Filed May 18, 1931 3 Sheets-Sheet 2 INVENTOR. I Jo/m Hall andez WW P y ATTORNEY J. HOLLAND-LETZ SEPARATOR DEVICE FOR ROUGHAGE ,MILLS Aug. 18, 1936.

A Filed May 18, 1951 5 Smeets-SheetI 3 lill INVENTOR. Jo/z n Hallan ZL e Z BY ATTORNEY.

Patented Aug. 18, 1936 UNITED STATES SEPARATOR DEVICE FOR ROUGHAGE MILLS l John Holland-Lets, Crown Point, 1nd., assigner I to The Letz Manufacturing Company, a corporation of indiana Application May 18, 1931, Serial No. 533,044

12 Claims.

The present invention relates generally to roughage mill and more particularly to a separating device for roughage mill for increasing the capacity and efficiency of the mill.

One of the objects of the present invention is to provide a novel and improved device which may be made in the form of an attachment for roughage mill for separating certain of the materials from certain other or the materials passing lO through the mill, such for example, as separating the heavier material from the lighter material and permitting only the heavier material to pass through the grinding mechanism for further reduction.

l5 A further object of the invention is to provide a novel and improved separating device for roughage mill, which will separate grain, corn, corn cobs or other heavy materials from the lighter materials as the same is passing through im the roughage mill and thereby reduce the amount of material which is required to pass through the grinding mechanism.

Another object of the invention is to provide an improved separator device for roughage mill in which a single fan mechanism is madeV use of, to furnish a suction as well as a draft therefor to more efficiently separate the heavier material from the lighter material prior to passing the heavier material through the grinding mechanism for further reduction.

These and other objects are accomplished by providing a construction and an arrangement of Y the various parts in the manner hereinafter described and particularly pointed out in the appended claims.

Referring to the drawings:

Fig. 1 is a front elevational view partly in crosssection of one form of my attachment for roughage mill;

Fig. 2 is a vertical enlarged detailed cross-sectional view of the cylindrical separator; the dash lines in this figure show diagrammatically how these parts are connected to the removed half of the separator cylinder;

Fig. 3 is a cross sectional view taken on the line 3 3 in Fig. 2;

Fig. 4 is a cross sectional view taken on the line 4 4 of Fig. 2;

m Fig. 5 is a cross sectional view taken on the line 5 5 in Fig. 2;,

Fig. 6 is a cross sectional view taken on the line 6 6 in Fig. 2;

Fig. 7 is an enlarged detailed cross sectional 5 ,view of a modified form of separator; the dash lines in this figure show diagrammatically how these parts are connected to the removed half ci the separator cylinder; l

Fig. 8 is a cross sectional view taken on the line 9 9 in Fig. 7; 5

Fig. 9 is a cross sectional view taken on the line 9 9 in Fig. 7;

Fig. 10. is a cross sectional view taken on the line id l in Fig. 7; Y.

Fig. ll is a cross sectional view taken on the 10 line Il lI in Fig. 7;

Fig. l2 isa cross sectional View taken on the line IZ I2 in Fig. l; and

Fig. i3 is a detailed View of the fan mechanism shown in Fig. l.

The present invention is an improvement over my cc-pending application, Serial No. 180,085, filed April 1, 1927 now matured into Patent No. 1,968,983 and Serial No. 451,101, filed May 9, 1930.

It is well known that the grinding of the forage 2o results in the pulverization of certain of the lighter ingredients, and theirconversion into an injurious dust. Heretofore it has beenthe practice to include in machines of this class an elaborate means for separating or extracting this in- 25 jurious dust from the rest of the forage. In the present method and machine the formation of this injurious dust has not only been prevented but the material which formerly pulverized into this dust is now included in the forage as a bene- 30 ficial element.

Forthe purpose of illustration, I have shown my improved separator device in connection with a form of roughage mill-disclosed in the above entitled co-pending applications. The roughage 35 mill in this instance comprises the usual supporting structure Yindicated by the reference character I5 which in turn is provided with the usual main shaft I6, cutter head I1, cutter head casingV I9, a circular grate I9, extending from and 40 surrounding the cutter head. Located at one side of the cutter head I1 and secured to the mainy drive shaft I6 is a conveyor screw 20. Positioned adjacent the conveyor screw is a grinding mechanism, generally indicated by the reference character 2l. Positioned over the conveyor screw 20 is a hopper 22. Positioned below the grate I9 is another conveyor screw 23 which is operatively driven through a train of gears 24. The conm veyor screw is mounted in a suitable trough 25 U" which in turn communicates with a conduit 26 for conveying the materials from the cutter head to a fan casing Vgenerally indicated by the reference character 21. Positioned between the conduit 26 and conveyor trough 25 is a removable plate or gate 28 for controlling the communication therebetween. WhenY the gate 28 is in place, the conveyor screw 23 conveys the material to an elevating fan hereinafter described. Located between the cutter head I1 and the conveyor screw and surrounding the main drive shaft I 6 is an enclosedfan casing 29 in which is mounted a fan 30, which in turn is secured to the shaft I6 and operatively driven thereby. Located in the lower portion of the fan casing 2871s an operiing 3! in which a removable plate may be inserted Y for controlling the communication'between the fan casing 29 and the trough 25. Extending. up- Y wardly from and in a position tangent to theV periphery of the fan 30 is a material conveying conduit 32 which is connected by an angularly disposed elbow connection 33 to an'opening in the side of my improved cylindrical separatorgenerally indicated by the reference character 34", the details-'of construction ofY which will be more: fully hereinafter described. Mountedy withinthe fan casing 21 is armixing and elevating fan 35-which turn4 is secured to one end of a. shaft 36v journaled in suitable bearings 31 and 38 secured to thek fari casing and main-frame respectively. The outer end of the shaft 36 is provided with a pulley-wheel 39 which-in Yturn isgeared to a drive pulley 40 by means of a belt inthe manner well-'understood inthe art. Positioned adjacent the pulley 40 is a large pulley 4I which is secured to the main shaft I6 and may be'connected up with the source of power for driving the mill.

Connected to the lower portion of the grind- *ing mechanism housing 2| is a conduit 42 which Y is connected to Vand communicates with a larger conduit 43 which conveys the material: frornmy improved separator device to the mixing fan casingv 2.1. Extending vertically upwardly and arranged tangentially tothe periphery of the revolving fan 3&'x'is a discharge conduit or spout 44,`

the uppervendof which may be connected to any suitablereceptacle forv receiving the mixed comminutedfmaterial.

The mechanism abovev described is substantially identical with the mechanism described in the above. referredV to'V co-pending applicatiom SerialfNo. 451,101" and for that reason it is be- Vlieved that amore detailed description oi the same issunnecessary. Y

The important features of the present invention consists in' ai new method of preparing forage-rand a noveldevi'ce which includes aseparating mechanism` for a` roughage millV which is especially Aadapted forseparatingthe kaifir-com, com, corn vcobs;.oats and the like `from the lighter material after the material has passed through the cutter head'so that Vonly theV heavy material (which, as

aY matter of fact, is the" only material requiring a further reduction); may be passed through the' grinding mechanism. Tests have shown that thel heaviermaterials constitute about one-fourth of all of the materials passing through the cutter head and by so separating thelighter material` from the heavier material, only about one-quarter of the material passing through the cutter head isrequired to Ypass through the grinding mech-- efficiency of the roughage mill, but also reduces to a minimum, the wear on the grinding plate of the grinding mill so that frequent replacement of the same is not required.

The separating mechanism hereinafter described, is capable of handling large volumes of material and separating the ,heavier from the lighter without the possibility of choiring.y This improved separating device comprises aY cylindrical casing as indicated at 45. Mounted inter- 10 nally of the cylindrical casing 45 and located at the lower end thereof is an inverted cone-shaped wall 46, which in turn forms in eirect an air compartment or air circulating chamber 41. This cone-shaped wall 45 isY provided with a plurality 15 of spaced apart apertures 48 fcr'the purpose hereinafter set forth. The lower end of this chamber 41 is enclosed by an inclined bottom 49 kwhich is secured to the lower end of the cylindrical casing 45 and to the lower end of the cone-shaped 20 wall 4.61! The" cylindrical separator 45 is securely fastenectto the upper end of the hopper 22'byv meansvof'fsui-table brackets `5D and bolts 5I. Com` municating with the circular air chamber 41 at onesidel thereof; is a rectangular spirally ar- 25 rangedi conduit.' generally indicatedliy the reference character 52. This spirally arranged conduitJFrZI-isY provided with an internal wall 53, which extendsinto an opening 54 'formed in the lower end oi?Y the wall of the cylindrical casing 45 at 30 one side of the air chamber 41. The upper end ofthe conduit 52 is connected to an opening orv aperture 54` which is. located in the cylindrical wall of the casing 45 above the inclined, inverted cone-Shaped'. wall 46' for discharging the air tan- 35 gentially in the cylindrical separator at a point above-the cone-shaped wall. It will be noted that the current of air is discharged spirallyin a direction opposite tothe incoming materialfat-.the

torrofi thev cylinder. Connected to the rear side 40 of the delivery spout. and'communicating therewith is a relat1vely reduced air conduit 55 which Y in. Yturn iaprovided with curved elbow as shown at. 56; The`y upper end of this. conduit is connected tangentially as shown at. 51 to an opening 58. in 45 the cylindrical portionof the separating casing 45st)Y that the'air may be discharged tangentially toY the-air chamberV 41 formed' between the in-Y clin'ed or conically shaped wall 46 and the cylindrical casing 45. The air conduit 55 isv provided 50 with a damper or valve 59 of any well known construction for regulating the amount of air pass-V ingfroml the conduit 55 into. the air chamber 46. The purpose ofrthis valve is to regula-te orrcontr'ol; the amount of air being supplied to the sepa- 55 rator casing so as to form an efficient means for eiieiently separating the heavier material from the' lighter/material in accordance with the type of material being fed into the roughage mill.V For example,v a greater amount of air is required to 60 pass through the conduit 55 to the air chamber 46 when the heavier materials such as corn are being fed into the roughage mill than is required to separate the heavier lmaterials from oats and' the like materials. 1 Y 65v The upper end of the cylindrical separator orf- Y casing 45.is.providedwith abeveled or conically shapedtapered top 60 which in turn is provided with an axial or center opening 6| in which is securely mounted a suction conduit 62.. .Thesuc-fo' tion conduit B2 is provided with a Ysemi-circular or double elbow 63 which in turn is connected to avertically disposed conduit 64. The lower end ofithe conduit 64 is connected to the conduitv 43 by means of an elbow 65. As previously described, the conduit 43 is connected to one side of the fan casing 21 at the axial center of the fan 35 so that upon a rotation of the fan 35 a suction is created within this conduit which leads to the axial center of the upper end of the separator casing 45. The lower end of the conduit 62 extends downwardly below the upper portion of the cylindrical casing 45 as shown at 66 and has a portion thereof as shown at 61 extending downwardly across the opening 68 in the upper end of the cylindrical casing 45 to which thedischarge spout 33 is connected. This baille wall 61 is curved as clearly shown in Fig. 4 and causes the material as it is discharged from the conduit 33 through the opening 68 to travelin a spiral or circular path when the same is discharged into the separator cylinder.

In order to prevent the suction from creating a column of air passing up through the axial vcenter of the cylindrical separator 45 and to more eiliciently separate the lighter materials from the heavier materials, I have provided cone-shaped baille 69 located at the lower end or mouth of the cylindrical separator. This baille 69 is supported in position by a bracket 10 which has one end thereof secured by means of a rivet 1I to a vertically extending flange portion 12 formed on the lower end of the inverted conically shaped walls 46. The other end of the bracket 1i) is secured by means of rivets 13 to the underside of the cone-shaped baille 69. Obviously from the above construction, the air is drawn around the periphery of the baille 69 and between the flange 1?. of the conically shaped wall 46 so that as the heavier materials are falling, the lighter materials will be circulated and drawn upwardly by the suction created by the fan 35 and these materials will be drawn through the conduit 62, 63, E4 into the mixing fan casing 21.

Extending over the delivery end of the endless conveyor (not shown) and covering a substantial portion of the cutter head is a hood 14 which is connected by means of a conduit 15 to an opening 16 (common to the conduit 26) on one side of the fan casing 21. This conduit 15 and hood 14 conducts the dust and pulverized material resulting from the cutting of the material adjacent the cutter head and draws the same into the mixing fan casing by reason of the suction created therein by the fan 35.

In order to further assist the fan 35 in elevating the cut material to the upper" end of the separator cylinder, I have provided an air conduit 13' which has one end thereof as shown at 14', communicating with the conduitl 55 below the damper 59, and the other end thereof communieating with the conduit 32 as shown at 15. This arrangement permits the fan 35 to assist in elevating the cut material in the conduit 32.

The operation of my improved separating device for roughage mill is as follows:

Let us assume that the gate or plate 28 is positioned in place so as to out off communication between the trough 25 and the conduit 26 leading to the fan casing 35 and that the opening 3| leading from the trough 25 to the fan casing 29 as indicated by 3| is opened by removal of the plate therefor, the material is placed on the conveyor (not shown) and fed into the cutter head I1 where it is cut and passed through the grate I9 into the trough 25. The material in the trough is then conveyed to the left as shown in Fig. 1 of the drawings, where it is elevated by the fan 30 and discharged through the conduit 32 into theY opening 68 in the upper end of the cylindrical separating casing 45. It will be noted that the conduit 33 discharges the cut material substantially tangential to the cylindrical casing and by reason of the circular baille wall 61 which is spaced from the opening 68 in the casing 45, the material is caused to be swirled in a circular motion within the cylindrical casing 45. This swirling motion of the material as it is discharged into the casing causes the heavier part to adhere closely to the inner wall of the casing while the lighter particles will be forced inwardly toward the axial center of the casing. As this is occurring within the cylindrical casing, it will, of course, be understood that the fan 35 is creating a suction through the conduit 43, G4, 63 and 62 to draw the lighter material up through the lower end 66 of the conduit 62 as the heavier materials fall downwardly in the separator cylinder 45. To further facilitate the eiicient separation of the heavier material from the lighter material, the conduit 55 receives a supply of air pressure from the discharge spout 44 which pressure is discharged through an opening 58 into the air chamber 41 formed between the conically shaped wall 46 and the lower end of the cylindrical casing 45. Substantially one half this air pressure is discharged through openings 48 in the conical wall 46 to assist in further removing the lighter material from the heavier material during its fall from the upper end of the cylindrical casing down into the hopper 22. The area of the holes 48 about the conically shaped wall 45 is approximately one-half the area of the conduit 55 so that the remaining half of the air pressure passing through this conduit is discharged into the tangentially discharging spiral conduit 52 which communicates with the air chamber 41 and is discharged into the opening 54 through the inner surface ofthe cylindrical casing 45, thereby discharging the current of air in a direction opposite to the circular discharge of the material coming through the spout 33. This action adds to the eilciency of separating the lighter material from the heavier material and precludes the possibility of choking. In this connection it will, of course, be understood if corn on the stalk is being fed intothe cutter head, the heavier material, such as kernels of corn, corn cobs, the heavier portions of the corn stalk, will be separated from the lighter material and will be dropped downwardly into the hopper 22 as the lighter material is drawn upwardly by the suction through the conduit 62 into the fan casing 21. The e'lciency of the separating cylinder is further facilitated by the cone-shaped bailles 69 by distributing the up-going currents of air between the outer periphery of the baille 6E! and the vertical flange 12 of the cone-shaped wall 46. The heavier material is then conveyed by the screw 26 to the grinding mechanism 2i where the same is comminuted and passed through the conduit 42 into the conduit 43, whereV the same is conveyed with the other or lighter material into the fan casing 21, where the same is then thoroughly mixed and discharged through the spout or conduit 44 into any suitable receptacle.

In Figs. 7 to 11 inclusive, I have shown a modied form of my cylindrical separator in which the general features thereof are essentially like those of the cylindrical separator of my preferred form shown in Figs. l to 6 inclusive, except that the conduit 55 is connected by an elbow 11 to an enlarged discharge spout 18 into an opening 19 located above the inclined or conical shaped wall 46. This spout 18 discharges its current of air substantially tangentially to the inner surfaceof the separator cylinder 45 'as clearly indicated by Fig. of the drawings. In this modified form, Va` branch of the conduit 55 is `connected by a-reduced conduit 89 which is arranged at right angles to the conduit 55 and communicated With- Vthe air chamber 41 toan opening 8| in the cylindrical casing l5 adjacent the lower end there-V of as clearly shown in Figs. 'I and 11.

The operation of this modified cylindricalvsep-Y arator is essentially like the preferred form shown in Figs. l to 6 except that the currentV of air or' air pressure passing through the conduit- .55 is distributed so that a portion of the same is-discharged through the branch conduit 80 into the cylindrical chamber 41 from Where it is'passed through apertures 48 in the cone-shapedv wall 45 -to assist inseparating the lighter materialsfrom the heavier materialsas they are'falling. The remaining portion of the air pressure passing through the conduit 55 is'discharged through the l opening 'i8 in 'thewall'of the cylindrical separator YV tangentially to the inner surface thereof and in a direction opposite to that of the incoming material which is discharged through the spout or conduit 33 into the'upper end of the cylindrical casing 55. Y Y Y From the above description it Will be readily seen that I have not only provided a simple, novel and improved separating device for roughage mill, but also an improved method for pre-v paring forage for cattle which will increase the capacity of the roughage mill fromv three' to four hundred per centV and at the same time will prevent the pulverizing of certain portions of the c material into dust which is well known to have a deleterious eiiect on cattle. It will also be noted that the suction fan which is incidentally used,

for mixing andelevating the mixed forage, is also utilized for performing the function of an air pressure fan for aiding the efficient separaf tion Vof Vthe lighter .Ymaterial from the heavier materialY and is also used for assisting in Velevating the out material in its Ytravel from the cutter head to the separating cylinder.Y

YWhile in the above description I have de scribedV my improved method of preparing forage for cattle and a preferred form of a device, which my invention may assumein practice, it

will of course, be understood that other modifications Inay be made to secure my improved method Without departing from the spirit and scope of the invention as expressed in the following claims:

What I claim is'my invention and desire to secure by Letters Patent is:

1, In a machine of the class described, corn-k prising a frame, a cutting mechanism mounted on said frame, a grinding mechanism mounted on said frame, a separating mechanism mounted lon said frame and positioned above said grinding mechanism for separating the lighter material from the heavier material, means for conveying the material from said cutter head to said separating mechanism, means mountedV on said `frame for mixing the material passing through said machine andV forY creating aV suction on one side of and an Vair pressure on the otherside of'V said separating mechanism and means forv utilizing a portion of the air pressure created by said last named means for assisting in conveying Vthe material from said cutting mechanism to said separating mechanism.

2. In a machine of the class described, com-` prising aframe, a cutting mechanism mountedy aos-1,489.

ont said frame',v ai separating: mechanism .mounted Y on said frame for separating the lighter'matefrialfrom the' heavier material, including a-sepa rator casing, a grindingmechanism mounted Von said frame for grinding the'heavier material, ak fan mountedgonV saidV frame for mixing the ground material with the lighter materialand a conduit connecting said fan with said casingfor creating a suction on one end of said casingY and an air pressureron the other end of casing,- said fan having a conduit connected adjacent said cutting mechanism for. assisting in'v conveying the material from said cutting mechanism to said separating mechanism.

3. In a machine of the'class described, com# prising a frame, a cutter headl mounted on said Y frame, a' grinding mechanismmountedonsaidH frame, a separating mechanism mounted ori-said Y frame including` a cylindrical casing, meansfi'ncluding a fanmounted on a shaft common to said cutterY head and said grinding,mechanismV for conveying the material from said cutter head and, discharging. the same into the-upper end of said casing tangentially to the inner surface thereof', and a mix-ing mechanism for mixing the ground material with the ylighter material', fsa-id:

Vmixing mechanism adapted tocreatev a' suctionE at one end of said casing andr adapted to ,create an air pressure at the otherv end. ofV said casingV for effecting theA complete separation of the lighter material fromthe heavier material.

4. In a machine of the class described, comprising a frame, a main drive shaft mountedl on said frame, a grinding mechanism mounted on said shaft, a'cutter head mounted on said shaft',

means-for conveying the material from said out4 ting mechanism to said grinding mechanism, anf Y elevatingfan mounted on said shaft, ay grinding mechanism mounted-on said shaft for grinding' the material cut by said cutting mechanism, a cylindricalI separator mounted above said grinding mechanism, an elevating conduit for conveyi ing the-material from said cutting mechanismV to said separator, a suction and mixing' fan mounted on said frame and' having a-c'onduit connecting the same with the upper endfof said;

separator, acasing for saidmixing fan, a discharge spoutconnected with said fancasing, a supplemental conduit connecting the ldischarge spout with the lower end of said separator casing for setting up theY spiral current of air therein,` and a conduit connecting said last namedconduit with said elevating conduit for. assisting in conveying andelevatingfof;A the cut- Vmaterial from said cutting mechanism tothe nected withl oneV endof said casing, a discharge:

conduit connected to said suction fan for disrcharging the material, therefrom, a conically shaped wall located at the lower end of said casing forming a circular air chamber therein, and means forming communications between said discharge conduit, and said air chamber for assisting the separation of the lighter material from the heavier material passing through said separating casing.

6. In a machine of the class described, comprising a frame, a cutter head mounted on said frame, a grinding mechanism mounted on said frame for grinding the material cut by said cutting mechanism, a separating mechanism located above said grinding mechanism, including a cylindrical separating casing, means for conveying the material from said cutter head and discharging it tangentially into the upper end of said casing, a single fan communicating directly with said casing and with said grinding mechanism for removing the lighter material from said separating mechanism and subsequently mixing the ground material with the lighter material, a conduitconnecting said fan with said casing for creating a suction on the upper end of said casing, and a connection between said fan and said casing for setting up a spiral current of air in the other end of said casing.

7. In a machine of the class described, comprising a frame, a cutting mechanism mounted on said frame, a grinding mechanism mounted on said frame for grinding the material cut by said cutting mechanism, a separating mechanism mounted on said frame, means for conveying material from said cutting mechanism to said separating mechanism, said separating mechanism comprising a cylindrical separating casing for separating the heavier material from the lighter material, a mixing fan mounted on said frame and adapted to withdraw the lighter material therein from said separator and mix the same with the ground material from said grinding mechanism, a discharge conduit connected with said mixing ian, a branch conduit for setting up a spiral current of air within said casing to aid in separating the lighter material from the heavier material passing therethrough, and a supplemental conduit connecting said branch conduit with said conveying mechanism for assisting in conveying the material from the cutting mechanism to said separating mechanism.

8. In a machine for preparing a non-uniform forage for cattle comprising a frame, cutting mechanism mounted on said frame for cutting the material into roughage form, a grinding mechanism mounted on said frame for reducing certain of the material cut by said cutting mechanism, means for conveying all of the material from said cutting mechanism in a direction towards the grinding machanism, a separating attachment interposed in the path of travel of said material from said cutting mechanism to said grinding mechanism for permitting only heavier material to pass through said grinding mechanism, a fan mechanism mounted on said frame for mixing the separated material with the ground material, conduits connecting said last named fan inlet and outlet with the opposite ends respectively of said separating attachment, and a conduit connecting said grinding mechanism with said last named fan.

9. In a machine for preparing non-uniform forage for cattle comprising a frame, a cutting mechanism mounted on said frame for cutting the material into roughage form, a grinding mechanism mounted on said frame for reducing certain of the material cut by said cutting mechanism, means for conveying all of the material from said cutting mechanism in a direction towards said grinding mechanism, separating means interposed in the path of travel of said material from said Vcutting mechanism to said grinding mechanism for permitting the heavier material only to pass through saidgrinding mechanism, a fan mechanism mounted on said frame for mixing the separated material with the ground material, conduits connecting said last named fan inlet and outlet with the opposite ends respectively of said separating means, and a conduit connecting said grinding mechanism with said last named fan.

l0. In a machine of the class described, comprising a frame, a cutting mechanism mounted on said frame, a grinding mechanism mounted on said frame for grinding certain of the material cut by said cutting mechanism, a separating mechanism mounted on said frame above said grinding mechanism for separating the lighter material from the heavier material including a separating casing, means including a fan mounted on a shaft common to said cutting mechanism i for conveying the material from said cutter head to said separating mechanism, a fan mounted on said frame for mixing the material passing through said machine, conduits connecting said last named fan inlet and outlet with the top and 5" bottom respectively of said separating mechanism for creating a suction on one side and an air pressure on the other side of said separating mechanism, and a conduit connecting said grinding mechanism with said last named fan.

11. In combination with a roughage mill including a frame, a cutting mechanism mounted on one end oi said frame, a grinding mechanism mounted on the other endof saidframe, means for conveying the material cut by said cutting mechanism to said grinding mechanism, a hopper positioned adjacent said grinding mechanism, a separating attachment mounted on said hopper for separating the heavier material from the lighter material and passing the former through said grinding mechanism, a mixing fan mounted on said frame for mixing the material passing through said mill, conduits connecting said mixing fan inlet and outlet with the top and bottom respectively of said separating attachment, and a conduit connecting said grinding mechanism with said last named ian.

12. In combination with a roughage mill including a frame, a cutting mechanism mounted on said frame, a grinding mechanism mounted on said frame, a conveyor screw located below said cutting mechanism for conveying the material from said cutting mechanism to said grinding mechanism, a separating attachment located between said cutting mechanism and said grinding mechanism for withdrawing material of certain specific gravity from material of different specific gravity, a mixing fan mounted on said frame, conduits connecting said last named fan inlet and outlet with the top and button respectively of said separating attachment, and a conduit connecting said grinding mechanism with said last named fan.

JOHN HOLLAND-LEITZ.

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