US1070552A - Hydraulic sizing-screen. - Google Patents

Description

F. E! sTEFFY. HYDRAULIG SIZING SCREEN. APPLICATION FILED OUT. 2, 1912.

mggg Patentad. Aug. 19, 1912 i SHEETS-SHEET 1.

L2 wzmmsws;

I N VEN TOR.

F. E. STEFFY.

HYDRAULIC SIZING SCREEN.

APPLICATION FILED 00T.2, 1912.

Patented Aug.19,1913.

4 SHEETS-SHEET 2.

WITNESSES:

APPLIGATION FILED OGT.2,1912.

Patented Aug. 19, 1913.

4 SHEETSSHEET 3.

WITNESSES:

F. E. STEFFY. HYDRAULIC SIZING SCREEN.

APPLICATION FILED 001. z, 1912 11 55g Patented Aug. 19, 1913.

4 SHEBTB-SHEET 4.

l .z; WITNESSES: 5 l 0 INVEMTOR.

Q UNITED STATES AT 1 FlC..-

FRANK E. STEFFY, OF GREAT. FALLS, MONTANA.

HYDRAULIC SIZING-SCREEN.

Specification of Letters Patent.

Patented Ari 19,1913.

Application filed October a, 19-12; Serial No. 723,558.

To all whom it may concern.

Be it known that I, FRANK E. S'rErrY, citizen of the United States, residing at Great F alls, in the county of Cascade and State of Montana, have invented certain consists in the novel detailsof construction more fully set forth in the specification and pointed out in the claims. a i

In the drawings, Figure 1 is a middle vertical longitudinal section of the apparains, with parts in elevation; Fig. 2 is a vertical transverse section on the-line 2-2 of Fig. 1, partsbeiug broken away; Fig. 3 is a horizontal section on the zig-zag line 3-3 of Fig. 1, parts being broken; Fig. 4- is ahorizontal sectional detail on the line 4-4 of Fig. 2; Fig. 5 is a middle vertical transverse cross'section through the cocentric and theupper cross-head supported thereby on the line 5-5 of-Fi'g. 2, showing the normal vertical position of the hanger- 'roil suspended from said cross-head, the drive-shaft being in side elevation; Fig. '6

is a similar sect-ionshowing the eccentric partly turned, and the cross-head and-slide thereof, and the hanger-rod, partially tilted from their normal position in response to thchorizontal movements imparted to the screen-tray to which the lower end of the hanger-rod is coupled; Fig' 7 is an enlarged plan or face view of the quadrant and sliding shoe forming the support for-the swivel which carries the upper end of the link or end-motion arm, parts being broken; Fig. Sis a cross-section on the line 8-8 ofFtg. 7 with the link arm and controlling springv therefor shown dotted; Fig. 9 is a diagrammatic view illustrating the motions imparted.

ofthe mill. The material which passes.

ident fied with this fine material.

through the mesh is then sized and classified by screens and hydraulic separators. The prevailing sizing screen does not work efficiently as desirable, and is open to the objection in that it does not segregate from the coarser particles, the exceedingly fine grains and matter known as slime (.when mixed with water) a portion of which is carried ofi with the oversize or material too coarse to pass through the mesh of the screen. In any operation of sizing by means of screens, inefficiency results from increased cost of screening, a large number of screens being required, and the material necessitating frequent rehandling. Not only does such a-method impose excessive wear on the screens and other machinery, but much valuable nuneral is lost in the form of slimeor fines, being carried away by the 'very fine material.

It is thcrefore the object of my invention to increase to a maximum the efficiency of screen-slung, this-being accomplished by associating with the screening action a .hy-

draulic separation which not only com pletely separates the individual particles from one another, but washes free the adhering partlcles of slime or fines which, 1n

conjunction with the movements imparted to the screen, assist in keeping the screen apertures-open. The oversize thus becomes thoroughly deslimed, permitting of independent concentration of the slimes and li'eheeihe recovery of the bulk of the'valnes In my invention the deslimed oversize is also completely dewatered as it leaves the screen,

being thus brought to a condition favorable to the specific mode of treatment or concentration adopted for relatively coarser material.

The advantages of thepresent invention will be apparent-from a detailed description thereof, which is as follows Referring to the drawings, and for the present to Figs. 1 to 8 inclusive, 1 represents a tank made preferably of wood, the same being divided into a series of compartments or hutchcs a, b, c, (three here being shown) by partitions w, w. Positioned within the tank is the screen tray 2 provided with a forward downwardly inclined extension 2 which projects through and beydnd the front terminal wall 10 of the tank, said wall being made of twosections disposed one on either side of said extension (Fig. 1). The tank 1 is reinforced by buckstays 3 connected at the top by cap-pieces 4 which support the shafting. No novelty however, is attached to such features as they are well understood in the art. The tray 2 carries the horizontal screen 5 deposited on a wooden frame of transversely disposed ribs r forming the bottom of the tray, the sides of the screen being clamped tovthe frame by means'of stringers 6 forced against the screen by means of wedges 7 driven between them and the lugs or plates 8 secured to the sides of the tray 2. The extension is provided with an inclined screen 5 secured in position in any mechanical manner, a bottom guard or apron 9 being secured to the front of the extension to direct the water into the compartment 0. The several compartments are 'providedwith discharge plugs 10 having an inwardly flaring passage h (F ig. 1 The forward terminal of the screen-tray 2 proper is connected to the wall w by means of flexible diaphragm or hinge 11 of leathery rubber or equivalent flexible sheet material, said diaphragm preventing intercommunication between the compartments 1) and c. The diaphragm is cofivexed toward the compartment 6 and permits of a combined vertical and horizontal reciprocation being imparted to the tray 2 and the screens 5,5, as will be more fully hereinafter described. Mounted over the a rear end {of the "tank 1 is the feed-box B (-preferably'lincd with iron 2') from which lead a series of transversely disposedc'ast iron spouts 12 discharging the pulp directly over the rubber lining 13 with which the rear end of the tray 2 is'provided.- Below the plugs 10 are arranged launders or boxes L in which the material discharged from'the respective compartments a, b, 0, is caught.

Under the present invention, a reciprocating movement "must be imparted to 'the screen jbotlivcrtically, and. at the sametime horizontally, the resultant of these motions .not only serving to cause the fines to pass '14: at the sides of the-'screen-tray are the lower ends of th ,(two pairs of) hanger rods lfiavl ose upper screw-threaded pore tions are passed through the ends o-f'the' pairs of cross-heads 16, 16, suitable jamnuts n being provided Where convenient to allow for proper fastening and adjustment of the parts (Fig. 2). The lower ends of the hanger rods have steel-bushed e es (in ,fillrn supplied *with a'brassbushingl, each pair'of rods (on opposite sides of the tray) having a common transverse bolt 17 passed through the eyes and the strap-ends between which the eyes of the rods are re* ceived. As previously stated, the cappieces 4: support the shafting, each cap-piece being provided with a bearing 18, for the support of the drive-shaft S operated by the belt-pulley P (or equivalent manner).

The shaft is provided with any conventional form of adjustable eccentric 19 the strap or ring 20 of which operates betweenthe crossheads 16, 16, a slide 21 adapted to longitudinally traverse the cross-head 16 being interposed between the eccentric strap 20 and connection with the cross-head 16) recipro,

eating back and forth along the cross-head 16 to conform to the horizontal travel of the strap 20 as'it is being drivenfby the eccentric; Theeccentric being adjustable, it follows that the degree of eccentricity may be varied by the'operator whereby a greater or le's'svertical throw may be impartedto the cross-heads and hence to the screen-tray.

Any standardim'a ke of adjustable eccentric may be employed asalr'eady stated.

It will be seen from the'drawings that the contacting. or engaging surfaces between the strap 20 and slide 21 are respectively convex and concavefollowing the surface of a sphere whose center lies on' theaxis of the shaft S. This curved surface of contact'be- 7 or ring 20' in a plane atrightangles tothe plane ofrotation of. the eccentricKIfig. 6),

and hence permitting the hanger-rods andthe cross-heads to which t-hey are coupled, to oscillate about the center of the joint aforesaidfwhich center as previouslystated lies on theaxis of the shaft S. The oscillation just referred to'will obviously beina plane parallel to the axis :of the shaft and since the scrcen-tray is suspended "from" the hanger-rods to which thisoscillation may be imparted, it fol lows that the tray may reciprocate not only yertical 1y but at the same time ho1-izo1itally, 'sa id horizontal movement being necessarily longitudinal. with the tray because parallel to the shaft S. T he -nie(-,hanism by which' this horiy'r'intal movement'is imparted to the screen-tray while the latter is reciprocating 'vertioally may vary, the following being an example :Bolted to the inner faces 01f the rear extensions 1 of the in Fig. 8,, to which a cap-plate 24: may be secured, the heads of thqzbolts t by which .the parts are secured spa ning the sides of the slot. The shoe and p-plate are suitably cored to receive the trunnions m, m, of a cored swivel 25., the swivel rotating in a plane parallel to the face of the quadrant. Through the opening D of the swivel freely passes a forwardly anddownwardly inclined link or end-motion arm 26, whose lower end is pivotal l-y secured between the ears 0 of the castings 27 bolted on opposite faces of the sides of the screen-tray, the link being pro vided with jan1-nuts n, n, for changing the efl'ective len 11 thereof, a coiled compression spring 28 eing interposed between the swivel 25 and the nuts n for purposes not only of cushioning the jar of the shake of .thescreen, but for maintaining a substan- -tiall fixed length for the link once the same has eon-adjusted by the proper shifting of the jam-nuts n, n. It will be seen that by shitting the shoe 23 along the quadrant and adjusting the efiz'ective length of the link or end-motion arm 26, any variety of horizontal strokes for the screen may be effected; and since the vertical strokes may likewise be adjusted bya proper adjustment of the eccentric, the character and degree of reciprocation to be imparted to the screen may be varied at pleasure depending on the nature and size of material to be sized or treated.

As the screen-tra reciprocates vertically under the action 0 the eccentrics 19, it is apparent that the links 26 coupled as they are to the tray, will be oscillated in a vertical plane; but since the links oscillate along arcs of circles whose centers are substantially on the axes of the swivels 25, the screen-tray will be reciprocated horizontally through a distance represented by the hori-' zontal component of the chord of the are described by the lower end of each link, the vertical component being necessarily responsive to the verticalthrow resulting from the action of the eccentrics. It follows that by virtue of the links or end-motion arms 26, the motion of the screen is resolved into an upward and forward stroke with a rising movement of the screen, thereby throwing the feed or pulp forward and causing it to travel rapidly over the screen toward the dewatering extension2'. With a falling of the screen themotion is downward and rearward thereby giving the particles suspended in the water an the tank 1 opportunity to fall ontofresh portions of the screen when they are 'mi'shed forward with the next or one direction) in hollow bearings 30 of suitable castings 31 bolted to a longitudinal timher or stringer 32 spanning the cap-pieces 4.

The pulp flows from the feed-box through the spouts 12 onto the rubber distributor lining 13 whence it flows in sheet form over the screen 5, the screen being just Submerged or close to the surface of the water in the tank 1 when it reaches the limit of its upward and forward stroke. In Fig. 9 I have shown diagrammatically and to the best advantage the operation of the screen. As the eccentrics 19 reciprocate the hangerrods 15 vertically, the link-arms 26. will cause the screw-tray 2 and screen 5 (and the parts 2, 5) to oscillate horizontally, the resultant following substantially the chord o of the are 3/ described by the lowcnend of the arm 26. The chord 1) forms the hypotenuse of a right angled triangle the perpendicular p of which represents theeffective vertical double stroke or throw to which the screen is subjected,the base in representing the horizontal component or the total distance traversed by the screen horizontally for a given inclination of the link-arm 26. By shifting the center of oscillation of the link-arm, a mere matter of adjustment of the shoe 23 along the slot .9 of the casting 22 and by varying the effective length of the link-arm and by varying the effective eccentricity o. the eccentric, it is clear that any desired shake or reciprocation may be imparted to the screen. By reducing the throw of the eccentric 19, the vertical component of the inclined path imparted to the screen will be reduced; by lengthening the arms 26 the greater will be the horizontal component of the path described by the screen; by lowering the centers of oscillation of the linkarms the. less will be the horizontal displacement of the screen; by raising the centers'lef oscillation of the link-arms the.

greater will be the horizontal component of the inclined path or reciprocation of the screen. These are matters quite obvious from the diagrammatic illustration in F 9 in which the link-arm is shown substantially at forty-five degrees to the horizontal when at the center of its arc of oscillation. A shifting of its, center of oscillation or a change in its eflective length will at once,

obviously affect the directionof the are described by the lower end thereof, or thatglSO 25 andthe particle 35 :Water in the y practically at all times submerged) and Work their waythrough the meshesor aperfinally settling through 55 size thus coupled to the screen-tray and hence vary the horizontal throw of the screen for any given vertical reciprocation ofthe latter.

The vertical reciprocation or component on the other hand-may be changed by proper adjustment of the eccentric 19. Referring again to Fig. 9, a particle of ore resting on the screen at the point. 0 when the screen is down, will be elevated to the point e as the 0 screen is raised.

When next the screen is depressed said particle will be left behind (because suspended in the Water in the tank) and precipitate onto the screen to the point 0?; when the screen is next elevated thep art-icle is raised to the point toand with the next depression of the screen the particle drops to the point 0 and so on). .Since the particle will always. fall substantially vertically whereas the screen-falls andrises diagonally,

it follows that the'particle'will be progressivelyadvancedforward along the screen 5 until-it reaches the inclined screen 5 Where it is dewatered, the Water flowing through -the;screen 5' intothe empty compartment '4', discharging over the edge of the extension-screen 5, and caught me suitable receptacle (not shown)., The path ofthe particle as just described is the 001m .mion path described by all particles which :are too large to pass through the screen (5),

@such particles collectively constituting the oversize. In the reciprocations of the screen the undersize or fine particles or slime be- ;come detached from the oversize by the tank (in which the screen is turesof the screen, thewater to the bottom of the compartments \a, b, whence they are discharged a stream of slime throughtheplugs 10. The presence'ot'. the water in-the tankl, and the specific character of reciprocation or shake im- -parted to the screen while submerged has 5 the efiect of not only advancing forward the oversize along the screen, but in desliming .the oversize, the fines all passing, through the meshes of the screen. beneath the screen and settlingto the bottom of their respec- .tive compartments. The deslimed oversize finally iswoiked off the extension screen 5 "Where it is dewatered, the water drained therefrom being caughtin the empty compartment c asalready described. The overdeslimed .and dewatered may be readily concentrated because no longer interfered with by adhering slime particles;

and the slimes on the other hand mayvbe separately treated. without loss in vahles. 0 This is a decided advantage flowing from the use of my invention. In Fig.,1;the water level in the tank 1, is represented by the dotted line as being a shade above the plane reached by the screen when at its highest 5 elevation.

As stated above, the swivel 25- constitutes but one form of pivotal connection for the fixed or fulcrum endof the link-arm 26; and in Figs. 10 andfill'l show 'a modified form of shoe 23 provided with lobes E for the passage of suitable securing bolts (such as 't) by which theshoe maybe-adjusted along the'slot s of the quadrant 22. "The shoe 23 is provided With a passageway D "having'inwardly convex walls; that is to say, cylindrical Walls gradually flaring outwardlv' 1n both directions whereby thelink 26 with its upper endsupportedinsaid' pas- 1 sage way D is free to'oscillate the necessary distance while performingits' function, as an end1no tion arm (see dotted positions in Fi s. l0, l1). Any other'equivalentform of l in connection may be substituted. .Should the Water accompanying from" the box B be insniiicient to maintain the-contents of the tank'l at the proper level/(m), additionalwatenmay be introduced through pipes W entering the side of the tank. In the final dewatering of the oversize onthe screen 5', not only water, butsome shine and otherjmaterial will .pass through this s'creeninto the empty compartment 0; and-if the slimes have'sufiicient value they may be-savedand subsequently suitably treated; otherwise'thecontent-s of.

I the'compartment c' are discarded.

lflaving'describ d my inve'tion whatI 'claimis I 1; In combination with a'Iwater-tank, a screen disposed adjacent the surface of the water in the tank, means forconducting a pulp sheet over the screen, 1neansfor1m parting to a downwardly and outwardly inclined- .screen-extension, carried by the screen and projecting beyond and out of the 'desliming rater-body, and a manner for catchingtfhe water and slime passed through the extension, the latter having-an edge-over which the-pulp combined horizontal" and "vertical reciprocations to the screen beneath the sur- .the oversize may discl'iai'ge 'to' a point be.

yond the container.

screen,positioned adjaeent'to 'thejsurfaee of I thmavater indhe tank,means "for dischargmg pulp Ill l|(t'-i; 'i -)l'm onto the screen,

means For imparting" properreciprocationS -to the screen b neath the surface of the Water in the tank for advancing the oversize of the pulp in-a given direction along the screen, a Water-tight flexible member connecting the screen to the tank, and a perforated member forming an extension of the screen for dewatering the oversize at a point beyond the flexible connection.

4. In combination With a Water-tank, a screenrpositioned adjacent to the surface of the water in the tank, means for delivering pulp onto the screen, means for imparting simultaneous vertical and horizontal reciprocations to the screen beneath the surface of the Water in the tank, Whereby'the solid material of the pulp is advanced along the screen in a given direction, a Water-tight flexible member connecting the screen to the tank, an empty compartment beyond the flexible member, a screen extension overhanging said empty compartment and rece ng the oversize advanced along the sub merged portion of the screen and dischargr ing' said oversize at a point beyond said en' pty compartn'icnt, the latter catching the uter drained from the oversize accumulating on the screen extension.

5. In combination With a tank filled with Water, a shaking screen submergible beneath the surface of the Water, a Water-tight flexible connection between the screen and a Wall of the tank, an empty compartment adjacent the wall to Which the flexible connection is secured, and a screen devvatering extension above the flexible connection projecting over the empty compartment.

In testimony whereof I aflix my signature, in presence of two Witnesses.

FRANK E. STEFFY.

Witnesses l v S. ll Cmxsn, T. P. ConoonAN.

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