US1905545A - Grinding mill - Google Patents

Description

April 25, 1933. c. E. WuENscH 1,905,545

GRINDING MILL April 25, 1933. c. E. wUENsCH 1,905,545

GRINDING MILL Filed March 6, 1951 2 Sheets-Sheet 2 Qffgl 6+ #s 46 A g 43.

Patented Apr.A 25, 1933 UNITED STATES camas aan WUENSCH, F JOPLIN, MISSOURI, AISSIGN'OR TO BENEFICIA- TION INCORIEORAJJEIID, A. CORPORATION. QF DELAWARE i @BINDING HILL Application inea. meas', 1931.. smal inagzsaoasasf Thisy invention relates to grinding mills,l and more vparticularly to a grinding mill of the ball type in which balls or equivalent\ means are employed for effecting the .grinding)operation. v

- ne of the main objects of my invention is to provide a grinding mill of simple con-r struction and high efficiency. A further object is to provide novel means for removingt D from the mill, during 'operation thereof, the

' fines or slimes during the grinding operation and produced thereb'y."-It is also an object of my invention to yassure thorough agitation of the balls and the material being round without interfering with the grind- 111g operation to a material extent. A further object is to assure proper travel.f of the grinding balls in a predetermined manner such as to effect maximum efficiency in the grinding operation. Another object is to provide a grinding bowl of novel constructi0n` such as to assure this desired travel of the grinding balls. Further objects and advantages of my invention will appear from the detailed description.

In the drawings:

Figure 1 is a plan view of a grinding-mill constructed in accordance with my invention;

' Figure 2 is a section taken substantially on line 2-T2 of Figure 1; l

Figure 3 is a central vertical sectional view through a modified form of the mill adapted for use as a disintegrator;

Figure 4 is a vertical sectional, view through the take-0E pipe and the screen therefor and associated part;

Figure 5 is a section taken substantially on line 5-5 of Figure 4; and

Figure 6 is a vertical sectional view through a modified form of screen and associated parts, parts being shown in elevation.

My mill includes a grinding bowl 1 mounted to rotate on a vertical axis. is conveniently formed of abott'om plate 2, lower and upper sections 3 and 4, respectively, and a top section 5. The bottom plate and the sections of the bowl are provided with suitable interengaging rabbets and projections forming step Joints, and with out- 0 wardly projecting flanges which receive bolts This bowl for securinthe sections and the bottom `plate together. gear ring 6 extends about section '4 and is bolted or otherwise suitably secured -thereto This gear -ring operates between upper and lower ball bearings .7' and 8, re'- spectively, the latter bearings'being suitably supported by a base 9 formed of concrete or other'suitable material, this base being preferably continuous and of annular shape in plan, employed or supporting the lower bearing if desired. The upper bearing is supported by means of brackets 10 suitably anchored to the base 9 and extending upwardly over the gear ring, the upper race of the upper ball Ibearing 7 being suitably secured to these brackets. The two sets of ball bearings provide antifriction bearings for the bowl and also serve to prevent any tendency of the bowl to tip or rock during rotation thereof. For rotating .the bowl'I- provide a source of power,such as an electric motor 11 of suitable type. A pulley 12 is keyed upon the shaft of this ymotor'and is connected by a belt 13 to a pulley 14 keyed upon drive' shaft 15. This shaft 15 is rotatably mounted in suitable bearing members 16 anchored to extensions 17, in the nature of piers, projecting vfromthe base 9. These extensions may be connected at their outer ends to provide a pier 18 upon which the motor 11 is suitably mounted. Shaft 15 is provided with a worm 19 suitably secured thereon and meshing with the gear ring 6. Preferably, a wheel 20, of considerably greater diameter than the pulley 14, is secured upon one end of shaft 15. This wheel is provided with suitably dis- `posedopenings 21 for reception of a bar or similar tool. This provides convenient means whereby a great leverage effect can be obtained for turning the bowl 1- lnanually, for the purpose of loosening and breakin up though suitably spaced piers may bematerials which have dried within the owl to such an extent as to become vcemented together and to the bowl and associated members, dueto the mill being out of operation for an appreciable period of time withthe break up the materials, it is then rotated by means of the motor 11 and associ' ated gearing. The bowll is rotated atrelavtivelyhigh speed, which increases the rate and effectiveness of the grinding operation. Any other suitable or preferred means mayr beem lo ed for rotating the bowl, and any ,suitab e riving connectlon between the mol son. V

' and f so suitabl 26. T

. tor lland shaft 15 may be employed. f u' The bowl 1 may be provided with a suitable liner, if desired, though such a linei` has been omitted for clearness of illustration. Also, the balls and the material to beground have been omitted, for the same rea- Referring more particularly to Figure 2, it will be noted that the interior of the bowl is ofv approximately elliptical shape in transverse vertical' section. rl `he linner surface of the surrounding wall of the bowl is i of arcuate shape in vertical section, the mid-.

portion .of-the arc being at approximately the centralhorizontal plane of the bowl so that the inner surface thereof curves upwardly and outwardly of the bowl at its lowerv portion.r and then upwardly and inwardly of the bowl at its upper portion. f The top portion of top section curves inwardly rovidesa lip 22 which projects' inward yof the bowl and defines an opening` 23 through the top thereof. When the mill is loaded with lgrinding balls and is standing still, the` top line of the charge of balls Each o f these members is provided, at itsV upper end, with an enlargement 3 0 which 1s suitably bored and threaded for reception of the lower portion of a capstan screw 31 which passes through, but is free from, beam 26 "rand flange. 28. A n ut 32 screws upon screw 31 and bears upon the upper face of beam 26, this nut cooperating with the screw for securing supporting member-29 in adjustment. By loosenin thecapstan screw' 31, the supporting member-29 can beturned about the screw to a'desired extent,gafter which enlargement 30 of this member is 6- forced against the ange 28, by-means of the capstan screw and nut .32, so as toeffectlvely lock member 29 in adJustment.

in members 9 I provide a-.deflector'33 suit- 5 aby secured thereto. 1' This c leflector is in s bracket is provided,- atthe clined to the vertical and is also inclined transversely of the bowl, the degree of the latter inclination beingcontrolled by the ad.- justment of the supporting member 29. As

be noted more clearly from Figure 1,l

the deflectors 33 are oppositely related, the

downward inclination thereof/being counter -ends ofthe deliectors are connected by a brace member'34 suitably shaped to extend about a take-olf pipe435 extending through the center of bottom plate 2.-

The take-off pipe 35 is suitably secured through bottom plate 2 for rotationY with the bowl, and extends upwardly within the bowl centrally thereof, this pipe opening into the bowl remote from the bottom of theV same.

The pipe 35 discharges into a funnel 36 which serves to 'direct the discharged material intora pipe line or launder 37, `by means Vof which the material is conducted to suitable receptacles for storage or for further treatment, as conditions mayrequire. Y

Referring more particularly to Figure 4, a screen 38 extends about the u per portion of pipe 35.v Ihe upper end o this screen is conveniently secured to an enlargement 39 .ofa rod 40 slidablv mounted through beam 26. A reduced rod'41 depends from enlarge-- ment 39 and is provided, at its lower end,

with a spider 42 the arms of which are slidably mounted through slots 43 in pipe 35 and extending from theupper end thereof. The screen is suitably secured to this spider, and extends downwardly beyond the same about pipe 35 in spaced relation thereto, the lower end portion of this screen fitting snugly about the pipe below the lower ends of the slots 43, as at 44. Since' the enlargement 39 is of less diameter than the pipe 35, the up# V `per portion 45 of the screen is. of frusto-conical shape, which is advantageous as facilitating passage of the-'finely ground materialsthereto. A guard 46 is bolted orotherwise suitably secured to bracket 27, and extends v downwardly about'the screen 38 in spaced relation thereto, this guard being provided with slots47 therein to facilitate admission to the screen of the finely ground materials which it is desired todischarge through the pr'pe 35,4 -The slots 47 `may be of any desired width, provided they arel not suiiciently Wide to `permit of the with registering openings which accommo grinding balls striking the screen fand causing injury thereto. A The,-l bracket'27 and the guard 46 are provided At the lower end of each of the support-- -`operate with a ratchet disk 49 which screws upon the upper portion of rod 40 and is adjustably secured thereon in a suitable manner, as by means of a set screw 50. During rotation of the bowl 1, pipe 35 rotates there.

f with and the screen 38 and rod 40 rotate with the pipe due to the engagement of the arms of the spider 42 into the slot 43of the pipe. Since ratchet disk .49 is lined to rod 40, it rotates with this rod and the teeth of this ratchet disk coact with the contacting surfaces of the ratchet pins 48 for Vcausing vertical reciprocation of the screen at high speed. In this manner the screen is vibrated and possibility Aof clogging thereof is eliminated. Under ordinary conditions, the vmesh of the screen may vary from to 65 mesh, though the mesh of the screen will depend upon the material being ground and may be Varied withinfwide limits.

In Figure 6, I 'have illustrated a modified form of means for vibrating or reciprocating the screen. A spider 51 is suitably secured to the upper end of pipe 35-for rotation therewith. The upper end of screen38 is suitably secured to a neck 52 depending from a ratchet head 53. I A rod 54, of squared or other suitable non-circular cross section, is secured at its upper end in neck 52, and is slidably 'mounted through an opening at the center of spider 51; and corresponding to the cross section of the rod. An extension coil spring.

A 55 is disposed about rod 54` and is confined between the spider and neck 52. This spring yieldingly urgesratchet head 53 toward a cooperating ratchet head 56 secured upon the lower end of a rod 57. The upper portion of circular cross section and is slidablethroug-h a corresponding opening .in thel upper end the bowl 1 isl rotated in a clockwise' direction, Vas indicated in Figure 1, the ratchet head 53 of a sleeve 58 which ,screws through cross beam 26 and is secured in adjustment there- 'l in byl a jam nut 59. An extensionfcoil spring 60is mounted about rod 57 and is confined between the upper end of sleeve 58 and a nut 61 which screws upon the'lower portion of rod 57. This nut provides convenient means for adjusting the tension of spring 60.y When is similarly rotated and the teeth of this ratchet head cooperate with the teeth of ratchet head 56, and the springs 55 and '60, for imparting vertical reciprocation to the screen 38 for vibrating the'latterf As has been above indicated, and as will be apparent to those skilled in the art, various mean's'may be employed for vibrating the screen; Ido-- not, therefore, lintend to in Aany way limibmy invention to the particular means disclosed- "for vibrating the screen, since any suitable or preferred means, other than the means Aherein disclosed, may be employed for this purpose.l

this rod is of squared or other suitable noni `be ground, it is rotated l Preferably the inner surface of the bowl is laidout on the spiral of Archimedes, both considered in horizontal section and in vertic al section, so .that the materials in the bowl tend Ato travel at-a constantispeed for every degree of angular rotation thereof. This tendency of travel-of the material, including by the defiectors 33. While the bowl is preferably laid out on the spiral of Archimedes, this is not essential and the shape of be suspended a suitable hoist 65, or an electromagnet 66, optionally. When the magnet is not in use it may be suspended from the beam 63 adjacent one end thereof, as shown, and

lthe grinding balls, is modified to some extent' when the hoist is not in use it may be susl pcnded from the bea-m in the same manner as the magnet. The magnet, in conjunction with .the trolley 64, provides convenient means for removing the `balls from"the mill,-

when desired or necessary, and placing them in a suitable hopper 67 .supported above and to one side of the bowl. This hopper is pro.- vided with an inclined chute 68, which may have any suitable removable'v closure means associated therewith, the chute being dlsposed to direct the balls from the hopper 67v into the vbowl 1 when the chute is opened. The hoist 65 provides means for handling parts of the bowl and associated structure.

Whenthe bowl l has been suitably charged with the grinding ballsv and the material to at high speed in the manner previously described. In the rotation of the bowl, thev grinding balls and the heavier pieces of material to be groundlare` urged outwardly by centrifugal force into contact with the surrounding wall of the bowl.

After thej'mill has been in operation for a short time, the inner lsurface thereof is, in effect, covered with a layer of grmdmg balls over. which the remaining balls and material in thel bowl' 1 m'ove during the grlnding opface vof the bowl, combined with the centrifugal action due to rotation thereof, the balls tend to move upwardly along the mner face The then displaced or pushed inwardly of the bowl bythe following balls and material',-

eration. Due'to the curvature ofthe inner andare discharged from the lip downwardlyr y and inwardly toward theI center of the bowl. In this manner, the material to be ground and the balls .tend to travel -from the bottom or lower portion of the bowl outwardly and then.

60 .wardthe central-dischargepointby the acupwardly along the inner face of the bowl and then are discharged downwardly toward the center of the bowl, so that such material and the balls tend to travel through anf'ap proximately elliptical path. This travel of the balls and the materlal, however, is modified by the dellectors 33. `The yballs and the material at the lower portion of the bowl are deflected upwardly and inwardly of the bowl, by the deiiectorsl 33, and are delivered at the central portion of the bowl, from which these balls and the material are moved outwardly by centrifugal force into contact with'the layer of balls at the'inner face of the bowl.I The travel of the material and the balls which travel over the layer of balls at the inner face of the bowl, instead of being approximately elliptical is through a path approximately in the form of the figure 8. This assures thorough commjngling of the balls and the material to be ground with the result that "gh eiiiciency in the grinding operation is obtained. Y

As the grinding operation continues, the heavier particles of material and the balls are thrown outwardly by centrifugal force and the lighter particles of material which has been ground, and which may be referred to as the nes for purposes of description, is crowded toward the center of the bowl at the upper portion of the mass, where it tends to accumulate. As these fines accumulate, they pass through the slots in guard -46 .and through the screen 38, entering the pipe 35 through the upper end thereof and through the slots 43 lwhen such slots are provided. These fines then pass downwardly through pipe 35, by gravity, into the funnel 36 and thence to the llaunder 37. This mill is adapted either for dry grinding or wet grinding. The material to be ground is fed into the bowl a3 required, and, when wet grinding, water 'is also fed intothe bowl' as required. In the latter case, when wet grinding, the fines which would be produced inl dry grinding form, with the water, slimes, which pass through the screen V38 into pipe 35 and thence into the funnel 36 and launder 37. By this construction I provide extremely simple and highly efficient means whereby the fines or slimes areeparated from the remainder of the mass of material 'in the bowl, during the grinding operation, and are taken off by gravity as they accumulate at the central portion of the bowl. This I consider of value as contributing to the eiiciency as well as the simplicity of construction and operation of the mill. A further advantage o f my `construction is that the f finest ground material in the mill is crowded or urged` totion of the coarser materials, duringV the grinding operation, the most finely ground materialbeing removed as it accumulates. This prevents excessif-7e grinding, such as 'the mill the?7 section 71 o LegnameA p encountered in ball mills of ordinary type,

with the -result that the material is ground more -uniformly and has a minimum amountv of colloidal forms. This is advantageous as greatly facilitating subsequent treatment of the ground material. Since the bowl is open at its top,- the grinding 'operation can be watched at all times and the rate of feed of the material and water, the amount of balls, the speed of rotation of the bow1,and the angle of deflection of the deflectors, can be controlled in such manner as to effect the most eflicient result. A further advantage of my construction is that no brokenor -worn dow-n balls are discharged from the mill, so that the balls are completely consumed in useful grinding work.

Since the deiectors 33 are spaced away from the surrounding wall of the bowl 1, and

4.are free from this wall, they do n ot seriously interfere with the circulation vof the balls and -material within the bowl, nor do they interfere with formation of the layer of balls at the inner surface of the bowl previously referred to. These deiiectors assure thorough agitation of the b alls and the material in the. lower portion ofthe bowl, but are so adjusted as not to present objectionable resistance to circulation of the balls and the material, this adjustment being effected with facility by means of the capstan screws 31 and associated parts in the mamier previously described.

It is desirable that suitable means be provided whereb the bowl can conveniently be washed out afyter completion of the grinding operation. For this purpose, l? provide a suitable opening through lower section 3 of the bowl, -this openingbeing normally closed by a removable plug 70, or other suitable means, bolted or otherwise suitably secured tosection 3. After completion of the grinding operation, the plug 70 may be removed and the interior of the bowl andV the parts therein may 'be thoroughly washed' and flushed out, the water and the mjateriallin suspension therein passing through the opening referred to.

A The .bowl of my mill is also well adapted for use as a disintegrator. For this purpose, the sections stand 5 may be replaced-by an upper or top section 71 which is curved outwardly and reversely to the lower portion of thebowl so as to provide an outwardly extending and downwardly curved lip 72. An annular sloping launder 73 extends about the bowl and beneath the lip 7 2 for'receiving'materials discharged therefrom. When using the mill as a disintegrator, no grinding balls are necessary, the residual .nodules in the materialitself servin to cause the desired 'disintegration thereo` during the rotation of the bowl.

move upwardl over the top the bowl and t entravelover As these nodules accumulate in .i so

- are not employed.

`to deflect materials in the vlower collects at the central portionv of the bowl and is taken olf through the take-olf as before. The "deiectors 33 may uire. Also, if desired, the screen 38 over t e upper portion of pipe 35 ma be employed although, under ordinary con `tions, this is not necessary. It is apparent, therefore,

that the bowl of my invention while ordinarily particularly adapted for use as a grinding mill employing grindin balls, can readily be converted into a bow suitable for use as a'disintegrator in which the grinding balls As above indicated, and as will be apparent to those skilled in the art, changes in construction and arrangement of parts of my invention may be resorted to without departing from the field and scope of the same, and I intend to include all such variations, as fall within the scope of the ap ended claims, inthis application in which t ey preferred forms only of my invention are disclosed.

What tI claim is:

1. In a grinding machine, a bowl mounted for rotation on a vertical axis, the interior of said bowl being of approximately elliptical shape in transverse vertical section, deflecting means within the bowl and disposed Y p ortion of the bowl upwardly and toward t e central portion of the bowl durinur rotation thereof, and a take-off pipe openm into the bowl centrally and remote from t e bottom thereof and disposed to takeoff by gravity fines gcculmulated at the central portion of the 2. In a grinding machine, a bowl mounted for rotation on a vertical axis, the interior.

of said bowl being of approximately elliptical shape in transverse vertical section, de

iiecting means within the bowl and disposed to deflect materials in the lower portion of the bowl. upwardly and toward the central portion of the bowl during rotation thereof, and a take-off pipe extending through the bottom of the bowl centrally thereof and opening into the bo`wl remote from the bottom of the same for taking oif by gravity fines accumulated at the central portion of the bowl.

3. lIn a grinding machine, a bowl mounted for rotation on a vertical axis, the vinterior of said bowl being of approximately elliptises cal shap'e in transverse vertical section, detlectin means within the bowl and disposed to de ect materials in the lower the bowl upwardly and toward t e central portion of the bowl during rotation thereof, a take-olf ipe extending throu h the bottom of the wl centrally thereo and open'- ing into the bowl remote from the bottom or not, as desirable 6r as conditionsmay rertion of i -lectors mounted upon said members and inclined transversely of the'bowl and to the vertical, said deiiectors'. being oppositely related -and disposedto deflect materialswithin the lower portion of the bowl upwardly and to'ward the central portion thereof during rol tation of said bowl, and a take-off pipeldisposed between the delectors and openingl through the bottom of the bowl centrally thereof, said pipe opening into the bowl centrally and remote from the bottom thereof for taking olf by gravity fines accumulated at the central portion of the bowl.

5. In a grinding mill', a bowl mounted for rotation `on a vertical axis, a take-olf pipe openi through the bottom of the bowl centrally t ereof and opening into thev bowl remote from the. bottom of the same for taking off by gravity fines produced in the grinding operation, the lower portion of the surrounding wall of the bowl being curved upwardly and outwardly and the upper portion of said wall beingl curved outwardly and reversely to said lower portion and forming a downwardly curved lip at the top of the bowl for discharge of materials therefrom, and a launder extending about the bowl beneath said lip for reception of materials discharged therefrom.

6. In a grinding mill, a bowl mounted for rotation on a vertical -axis and a take-olf pipe opening through the bottom of the bowl centrally thereof and opening into the bowl remote from the bottom of the same for taking oil by gravity fines produced in the grinding operation, the lower portion of the surrounding well of the bowl being curved upwardly and outwardly and the upper portion of said wall being curved outwardlyand reversely to said lower portion and forming a downwardly curved lip at the. top of the bowl for discharge of materials therefrom.

In witness whereof, I hereunto subscribe e

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