US1306188A - Mechanical classifier - Google Patents

Description

F. E. MARCY.

MECHANICAL CLASSIFIER.

APPLICATION FILED MAY25. I9I8.

Patented June 10, 1919.

3 SHEETS-SHEET I.

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F. E. MARCY.

MECHANICAL CLASSIFIER.

APPLICATION FILED MAY 25, 191B.

Patented J 11116 10, 1919.

3 SHEETS-SHEET 2.

F. E. MARCY.

MECHANICAL CLASSIFIER.

, APPLICATION FILED MAY 25. l9l8.

1,306,188. PatentedJune 10, 1919.

3 SHEETS-SHEET 3.

W/ TNESSEJ #w asag lNVENTOR.

ATTO/P/VE X 11 n SA FRANK n. IVlARCY, on SALT LAKE CITY, UTAH.

MECHANICAL CLASSIFIER.

Specification of Letters Patent.

Patented June 10, 1919.

Application filed May 25, 1918. Serial No. 236,488. i

To all whom it mac concern:

Be it known that I, FRANK- E. M-AROY, a cit-izenofthe United States, residing at Salt Lake City, in the county of Salt Lake and State of Utah, have invented certain new and useful Improvements in Mechanical Classifiers, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part hereof. f i

The present invention is directed to improvements in what are known in ore dressing as mechanical classifiers in contradistinction to the purely hydraulic type of machine in which the agitation is effected by an upward. current of clean water through which .the coarse or heavy particles of the material under treatment arecaused to fall,

. and by which the fine particles or fines are separated from the coarser particles or sands. The classifier under consideration may be used in circuit with ore grinding mills, serving the specific purpose of returning the coarse sands which form a compocoarse sands from floating away, the fine nent part of the finished product of the mill, back to the mill for further grinding. The object sought of course is to effect a separation between the coarse sands and fines without the use of screens, the latter being impractical for sizes finer than 40 mesh. So far as concerns the immediate improvement herein,

one of the objects sought is to provide a classifierwhi-ch will remove a maximum or any desired quantity or character of fines and prevent their return to the mill wlth the coarser sands requiring further treatment or regrindmg. A further ob ect is to provlde means for varying the character of agitation imparted to the pulp,- producingat pleasure an upward or downward current, or mere agitation, and thereby effectlvely controlling; the classification of the material. A further.

object is to provide means for feeding the pulp to the classifier below the surface of the pool or plane of overflow to preventany material being however free to rise through the pulp to the surfaceand pass off with the overflow. A further obj ectis to prevent the fine "sands fromtaking adirection away.

from the overflow (or toward the conveyer) the tendency of the finesto take the wrong direction in this type of machine being due to the circulationset up by the conveyor plowing through the pulp. A further object is to provide a classifier which will treat a maximum quantity of material in a minimum amount of time; one which is simple in construction and containing a minimum number of parts; and one possessing further and other advantages better apparent from the following detailed description in connection with the accon panying drawings in which- Figure 1 represents a side elevationof my improved classifier; Fig. 2 is a. top plan thereof with feed hopper omitted; Fig. 3 is a vertical cross-section on the zig-zag line 3+3 of Fig. 2; Fig. 4 is a rear end elevation; Fig. 5 is an end view of the tail pulley or drum of the belt conveyer; Fig, 6 is an elevation of the lower end of the stirrer shaft showing the stirring blades set at an angle to the plane of rotation thereof; Fig. 7 is a vertical longitudinal sectional detail on the zigzag line 77 of Fig. 2; and Fig. 8 is an elevation of the lower end of the stirrer shaft showing the stirring blades set parallel to the planeiof rotation thereof;

cferring to the drawings, 1, represents an oblong tank terminating at one (the lower) end in a relatively deep portion forming a sorting basin or compartment C, and in a relatively shallow portion or extension D at the opposite (or upper) end, the level of the pulp or water line in the deep portion being indicatedby the dotted line a" in Fig. 1. The maximum depth of the pulp in the sorting compartment will of course depend on the inclination or pitch of the inclined bottom a of the tank, the plane of overflow from said compartment being along the upper edge of the vertical terminal wall 6 of the tank. The overflow from the sorting compartment is caught in a launder 2 by which it is conducted to any suitable point for further treatment and the recovery of the fines. Operating within the sorting compartment C on each side of the medial longitudinal line or axis of the tank 1 is a vertically disposed stirrer shaft 3, the shafts being supported by the timbers T as shown or in any other suitable mechanical manner. The stirrer shafts are operated froma transverse shaft 4: disposed across the tops of the timbers T, the said shaft having rotation imparted thereto by means of a belt B leading from the adjacent end of a parallel driveshaft5 supported in suitable bearing blocks 6 at the upper end of the shallow portion D of the tank. with step pulleys P and P respectively over which the belt B passes, and by means of v which the speeds of the shafts may be reguthe stirrer shafts, the pinions l3 engaging the pinions 1 1 of the respective shafts on opposite sides whereby the shaft 4. imparts to the stirrer shafts 8 simultaneous rotation in opposite directions (see arrows Fig- 2). The lower end of each stirrer shaft terminates in a square hub or enlargement 15, opposite each face of which is screwed a blade or agitator 16, the blade being held against rotation by a setscrew 17 carried by the hub and driven firmly against the screw stem 18 of the blade (Fig. 6). The blades being rotatable about the axes of the screw stems 18 may be adjusted to any angle or pitch relative to the (horizontal) plane of rotation of the stirrer shaft, as shown in Figs. 6 and 8. In Fig. 6 the blades are set at an angle to the rotation plane; and in Fig. 8 they are set parallel thereto. They may be set to any angle between the horizontal and vertical positions as clearly obvious from the draw ings. The shaft 5 has rotation imparted thereto from the belt pulley 19, a loose pulley 19 being mounted adjacent to the tight pulley 19 as well understood in the art.

The outer face of the belt conveyer 11 is provided with a series of transversely disposed angle bars 20 which are slightly bowed or arched outwardly (Fig. 1) to conform to the crowned peripheries of the drums 10 and 12. The legs of the angle bars projecting from the beltform rakes or scrapers whose free edges travel in proximity to the outer sweep of the blades 16 and operate close to the upper surface of the inclined bottom a, of the tank, thereby carrying the sands from the sorting compartment to the upper end of the tank where the sands discharge into the inclined launder 21 whence they are conducted to the mill for regrinding- As shown in the drawings, the bars 20 extend beyond each side of the belt 11, the center of the belt being disposed along the medial longitudinal axis of the tank. T0 impose proper tension on the belt the bearings or blocks 6 supporting the drum shaft 5 (and shaft 9) are made adjustable as well.

understood in the art.

It was pointed out above that in classifiers of the type under consideration the fine ma- The shafts 4 and 5 are provided terial has a tendency to flow over in the direction of the conveyer as indicated by the dotted arrow in Fig. 1, whereas it should 7 flow toward theoverfiow edge e of the wall 1 Z). In the present embodiment of my invention this tendency of the fines to flow in the 7 wrong direction (toward the conveyer) is overcome or arrested by the side aprons 22, these being in the form of sheet metal strips supported on angle brackets 23 secured to the sides of the deep portion of thetank, said aprons being disposed'at an incline corresponding tothe pitch of the upper lap of the belt conveyer 11, the lowerportions of the aprons describing substantially a semi-v circle (Fig. 7). conformable to the curvature of the periphery of the tail drum 12, and

terminating below. the center line ofxsaid' drum. The upper ends of the aprons extend above the pulp line at, the iniier'longitudinal edges thereof being spaced sufficiently from the adjacent or side edges of" the conveyor belt toprevent rubbing against the belt.

The aprons. are moreover disposed slightly chanical manner.

To prevent any coarse sands from floating away by way of the overflow fromthe sort ing compartment, I mount across thetank a feed box or hopper 2 1 the discharge The aprons are in the namouth 24; of which extends below the pulp line 9:, the-pulp being discharged from the hopper preferably at apointbetweeir the stirrer shafts 3 and the tail drum 12. By introducing the feed below the surfaceof the pool, or pulp line w, thefine particles 7;

are permitted to rise up through the pulp and be discharged by wayof the'overfiow, the coarsesands remaining behind; NVere the pulp discharged on top of the pool,

some of the coarse sands would float'away' and become mixed with the' finesthereby resulting in imperfect classification. The separation of the fines from the coarsesands is thus enhanced by disclnrging the pulp into the compartment C below the surface of the pool.

The operation is substantially asfoll'owsz' The pulp" (water mixed with the crushed ore or other material) is delivered to the hopper 24: from any suitable source, the hopper discharglng the material at a convenient point beneath the surface of the pool or pulp line' a: so that none of the .coarse sands can float:

away over the edge 2 (Fig. 1). Rotation being imparted to the shaft 5 clockwise (see arrow in Fig. 1) the pinion 7 on said shaft will impart a counterclockwise. rotation to the gear wheel 8. .andto the drum 10 car ried by the shaft 9, thereby imparting a corresponding movement to the belt collveyer 11 as shown by the arrows in Fig, 1. Through the instrumentality of the belt B, rotation will be imparted to the shaft l (Fig.2) and from said shaft to the stirrer shafts 3, 3, as clearly obvious from. the drawings. vention of course is to separate thev fines from the coarse sands, the object sought being to keep the fines afloat. in the pulp inthe sorting chamber and cause them to move toward the overflow edge e of the wall I), and at the same time cause the coarse sandsto be dropped and advanced toward the tail drum 12 andthescraper blades 20 of the conveyer, said scrapers pushing the sands upward along theinclined bottom a and causmg the1r dlscharge over the upper edge of said inclined bottom into. the launder 21. To effect this separation due regard must be had for the intensity and character of the agitation brought about by the revolving blades 16. The degree of their pitch to the rotation plane will determine the character of current and degree of agitation, and likewise the path of advance of the coarse sands. Depending on the degree and direction of that pitch we may produce an upward current or downward current; or, by turning the blades into the .plane of. rotation as shown in Fig. 8 (in contradistinction to the angular disposition shown in Fig. 6), we may produce mere agitation without any defined upward or downward current. The adjustability of the pitch of the blades to the plane of rotation is an important feature in the present invention as it enables me to adjust the agitation to the character of the pulp operated on and thereby secure efi'ective separation of the fines from the coarse sands. In the present embodiment of the invention the fines are prevented from taking the wrong direction by the deflecting aprons or diaphragms 22, which, together with the belt 11 (barring clearances of course) form an efiective barrier against any tendency on-the part of the fines to flow toward the conveyer. In fact the aprons and belt quite well segregate the sorting compartment C from the rest of the tank 1.

' The coarse sands of course are caused to ad- The main purpose of, the in-,

any desired speed may be imparted to the stirrer shafts 3, 3. The blades 16 may of course be set to such a pitch and thespeed of rotation of the stirrer shafts be so increased as to cause a portion of the coarse sands to be carried away with the fines over the overflow edge e. If the agitation is moderate a larger volume of sands will settle than would be the case where the agitation was violent. .Again, the pulleys P, P, may be changed so that any desired relation of speeds between the belt conveyer and stirrer shafts maybe obtained, thereby permitting the speed of the belt to be increased in the event of a settling of large quantities of coarse sands. Obviously the classifier is not restricted in its application to the treatment of ores, but may be used 011 any material capable of classification. The apparatus. may be changed in many details without a departure from the nature or spirit of my invention. Features shown but not alluded to are well known in the art and a description thereof is here unnecessary. The term belt as used herein is not to be restricted to an imperforate endless member as shown but is to be understood as including any endless member imperforate or open and made of any material whatsoever to which suitable rakes or scrapers such as 20 or their equivalents may be attached.

Having described my invention what I claim is: p

1. A classifier of the character described comprising a tank having a bottom sorting compartment or. basin provided with an overflow, and an inclined portion leading above the pulp line in said basin, means extending below the pulp line to a point between said inclined portion and overflow for feeding a charge of pulp to the basin, a belt conveyer in said tank having one end dipping below the pulp line and the opposite end terminating at a point above the pulp line, agitating devices in the basin positioned basin provided with an overflow, and an inclined portion leading above the pulp line in the basin, means extending below the pulp line to a point between said inclined portion and overflow for feeding a charge of pulp to the basin, a belt conveyer having one end dipping below the pulp line and the opposite end terminating at a point above the pulp line, agitating devices positioned below the pulp feed between the point of overflow and the adjacent end of the conveyer, means for imparting a rotary sweep to said agitating devices about an aXis through the pulp line,

' and means for adjusting the angularity of comprising a tank provided with a sorting" chamber having an overflow, the tank hav} ing an upwardly inclined extension or per 7 tion leading from said sorting chamber, a

belt conveyer in said extension having a lower terminal in the sorting chamber and operating to conduct the coarse sands therefrom to a'point above and beyond thesorting chamber, a rotary stirrer shaft in' the sorting chamber between the point of overflow thereof and the adjacent end of the conveyer, pulp-feeding means discharging below the pulp line at a point between the stirrer shaft and inclined portion ofthe tank, agitating blades on the shaft, sweeping in proximity to the adjacent terminal of the conveyor, and means for maintaining the blades at any desired pitch or angle to the plane of rotation thereof about the axis of the stirrer shafti 4. In a classifier of the character described, a tank provided with a sorting compartment having an overflow, and with an inclined extension leadingv therefrom to a point above the pulp line in said compartment, an endless conveyer disposed in the tank and dipping at one end below the pulp line in the sorting compartment, the sides of the conveyer being spaced a suitable distance from the side walls of the tank, anagitating device in the sorting compartment inthe adjacent end of the conveyer, and suitable aprons or d-iaphragms spanning the spaces between the tank walls and the sides j of the conveyer tooffset anytendency of the fines to flow in a direction away from the overflowand toward the conveyer.

--5. In a classifier of the character described, a'suitableftank provided with a sorting compcrtment having an overflow, an endless conveyer dipping I with one end below the pulpline in the compartment a drum in the compartment for the support of the conveyer, the sides ofthe-conveyer being 7 spaced from the adjacent walls of the tank,

scrapers disposed across the conveyer andprojecting beyond the sides thereof, suitable aprons spanning the'spac'es between the tank' walls and "the side edges of the conveyer but clearing said edges and positioned slightly;

below the path of travel of the scrapers and clearing said scrapers, the'said apronsbeing disposed in the general plane of travel of the upper lap of the conveyer andextending to the pulp line at the top, the lower portions dipping below the" pulp line and being curved to conform to the curvature of the drum peripher and an agitating device in the'sorting compartment,

In testimony whereof I affix my signature,

in presence of'two witnesses. V

' FRANK E. MARGY. lVitnesses VIOLA P. DRUSHAL, ROBERT E; MARK.

Copies of this patent may be obtained for five cents each, by addressing the C0mn1issioner..of Patents, Washington, D. G.

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