Патент USA US2134154код для вставки
Oct.' 25, 1938. H. H. SMITH ‘ 2,134,154 ORE DRESSING JIG ' Original Filed June 25, 1952 V I I "I z‘ :i All‘! A, DOWN STROKE ‘ 'A 41 Hays . 2,134,154 Patented Oct. 25, 1938 UNITED STATES PATENT‘ OFFICE‘ 2,134,154 ‘ ORE. DRESSING JIG Harold .Hardy Smith, Parkview, Johannesburg, Union of South Africa, assignor of three-fourths to General Mining & Finance Corporation, Lim ited, Johannesburg, Union of South Africa Application June 25, 1932, Serial No. 619,309. ,Re-1 newed July 15, 1937. ‘In the Union of South Africa July 27, 1931 6 Claims. (01. 2094425) The present invention relates to jigs for con centrating ores and other materials. ' The principal object of the invention is to con struct a jig adapted for a large capacity per unit of screen area, with a good recovery of the ?ner concentrates and low dilution of the tailing, and capable of handling a feed containing a wide range of particle sizes. ' ‘The pulp travelling over a sieve bed from the Fig. I is a vertical section. , Fig. II is an enlarged plan of a part of the ad justable sieve rim. Fig. III is a detached View of the vhead motion. 7 - Fig. IV» is a diagram relative to the head motion. ; r The hutch consists of the conical vessel 2- hav ing any appropriate outlet for concentrates such as the goose-neck 3 extending from its lower part. Around the top of the hutch is the annular tail 1 O feed point to the point of discharge tends toyin crease in bulk due to the additions of hutch water ings collecting launder 4 having an outlet'5. ‘ through the bed; and’if such increase of bulk re sults in largely increased velocity of flow over the bed, ?ne valuable particles are prevented from 15 settling and are lost. Such increase of velocity and resulting loss can be minimized by making the sieve in the shape of a buddle, with feeding means at the centre and boss 6 and arms ‘I: the circular upper and lower peripheral discharge of the tailings; but in the few known instances where this arrangement has grids 8, 9 resting on and secured to they spider; and the circular screen 10 between the grids. The jig illustrated is intended to deliver concentrate only through the sieve, the'bed accordingly con sists of a lower layer II of ragging and an upper layer l2 of ore. The ragging is retained in posi tion by the cells of the upper grid 8. The similar cells of the lower grid 9 constrain the water cur been proposed it was embodied in ‘constructions rentsfor vertical movement.v which were inherently incapable of large outputs The sieve is provided with a raised rim 13 to retain the ore column l2. For adjusting the and clean concentration. ’ ‘ ‘ According to one aspect of the present inven tion, dilution of'the tailing by hutch waterv is depth of the ore column there is shown a'sup plementary rim adapted to be clamped to the 25 minimized and rapid movement of the material over the bed together with high grade hutch con rim l 3 so as to project to the desired height above the latter. It comprises several arcuate sections centrate is attained by constructing a‘ jig with a circular sieve which is vertically reciprocated, is 3 O fed at the centre, and discharges the tailings at its periphery. CO U! VThe sieve comprises a spider consisting ofa ' ' - l4 (Figs. I and II) provided at‘ their adjoining ends with lugs I5 and clamp bolts l6 bywhich the sections. are drawn together to clamp onto 30 the rim [3. Between the lugs are soft rubber or The invention provides a head motion for the sieve such that, in each reciprocation, vsaid head motion moves the sieve downward with constant acceleration approaching a point beyond half the like ?lling pieces I‘! which close the gaps between the lugs I5 and so prevent ore from escaping stroke, at which it attains its maximum velocity, ‘ A surge grid ‘ l8 is?xed in the hutch immedi through.them,_whilst allowing the lugs tobe ad justed towardsone another. = I r then said head motion suddenly retards it and re ately below the sieve to prevent surging of the verses it into the upstroke so that it attains its hutch water between the inner and outer areas - maximum velocity at less than half the stroke, and said head motion then moves it with constant deceleration toward the top‘ of its stroke, the movement in each reciprocation being purely vertical. - The invention further provides a fluid tight seal between a vertically reciprocating jig sieve and the hutch; as 'by means of a rubber or other ?ex of the sieve. ' 35 ' I9 is a strip of rubber secured at its edges re spectively to the rim 'of the sieve and to the inner rim 20 of the launder 4, and making a ?uid tight seal between the sieve and the hutch. It is de sirable to minimize as far as possible the tendency of the‘ strip 19 to act as a water-plunger, since ‘ whilst in the case of a circular sieve discharging such plungeraction tends toupset the action of the reciprocating sieve. The strip l9v should therefore approximate to a vertical position, but such position often involves practical disadvan tages, and it has been found that if, when fully tailings at its edge, contamination of the hutch product by the tailings is de?nitely avoided. zontal of not less than aboutthirty degrees, it , ible strip having its edges secured respectively. to said parts. In this way interference with the re sults last described, by leakage of water or air 5 O between the sieve and the hutch, is avoided; .A jig constructed according to the invention is 55 shown in the accompanying drawing in which I extended, the strip makes an angle to thehori will, when relaxed,'assume the S cross-sectional form shown in which, the inward and outward 55 2 2,134,154 bulges aboutv equal one another and thus prevent water being displaced. been constructed with the following dimensions, viz:+ The boss 6 is secured to the vertical shaft 2|. Inches At the upper end of the shaft is an open cross Length of lower toggle link 25 ___________ __ 10% head consisting of the crossbar 22, side rods 23 Length of upper toggle link 24 __________ __ 6% extending vertically therefrom andya cross bar Thickness of pitman between links ______ __ 31/2 24 carried by the rods 23. Effective length of pitman ______________ __ 12 Said cross head accommodates the head motion whereby the shaft 2| is'supported and recipro 'iEccentric stroke _______________________ __ 1% 7 Centre’ of shaft 34, % inch below the mid 10 cated vertically.‘ The head motion comprises them“ ‘ point between the adjacent ends of the toggle links 25, 26, the former of which rests at H its lower and outer end upon a block 2‘|_ supported ' on a fixed part 28; and the latter of which carries 10 toggle links when the mechanism is in the Fig. III position. Such mechanism produced a sieve motion rep on its upper and outer end the cross bar 24 of the 15 cross head. The outer end of the upper link-26 resented by the graph Fig. IV where abscissae is in the axial‘ line of the sieve and ‘the shaft 2|. ‘ represent ‘time and ordinates represent sieve ve By means of the screw 29 which shifts the block locity.‘ The point A of the graph corresponds with 21 horizontally, the outer end of the lower link the commencement. of the downward stroke and can be adjusted to be in the same axial line as .. point B. lies at about six-tenths of that stroke. 20 shown or to the left of said axis. A rod 30 ex ‘ The straight portion of the line approaching point 20 tending upward from the cross head engages a guide 3| to counteract the side thrust of the toggle. ~ '? ‘ . ' ' ‘ Bindicates'substantially constant increase ofve locity, whilst the sharp peak at B shows the sud den retardation. The steepness of the line from The inner ends of ‘the toggle links‘ engage a B to C exhibits the rapid reversal to upward pitman 32 which is reciprocated endwise by an movement and compares with the slower‘reversal eccentric 33 on the shaft 34. The pitman lies ' at the top of the strokershown by the less steep , 1 ' ' approximately 'at an angle of ninety degrees to line C. A. B.‘ By shifting the block 21 over to the left, the the toggle but the shaft bearings 35 are adjust able vertically on their ?xed support, toienable length of the sieve stroke is increased and the efé 30 such angle to be varied. The shaft‘is rotated as fects mentioned above in reference to the graph 30 . . by abelt pulley 35 and is ?tted with a‘fiy-fwheel ‘ are intensi?ed. The pulp to be treated is delivered by a‘pipe 31 vfor maintaining regularity: of rotation." Con 43 into a stationary annular hopper 44 surround tact between the bar 24 and the toggle is main tained by'springs 38 compressed between a ?xed ing the shaft 2|. Said feed pipe delivers the 35 member 39 and the cross-arm 4|! on the shaft 2|. pulp tangentially into the hopper‘so that 'it is The tension spring“, the’compressionsprings well distributed all around the same. The hop 38 and the reciprocating parts‘renresented main: per has a bottom discharge in the form of a short pipe 45 which’ directsthe pulp into, anannular ly by the sieve, “form a system adapted for verti cal oscillation with a natural frequency: and when 40 forcibly displaced from its neutral ‘position and released. would continue'to oscillateuntil stopped by friction." The headfrnotion therefore'has mere ly to maintain the reciprocation by making“ up friction lossesand is not called upon tofsustain 45 the weight of the sieve." It has'only to govern the accelerations and’ decelerations ‘of the sieve and not to provide thelwhole ‘of the force neces: sary for each such operation.’ . The natural fre quency of reciprocation of the systemldepends 60 principally'ron the mass of the loadedh‘sieve and the upward and downward pressure of the re spective springs. By making the spring pressures su?iciently great relatively to the mass, the nat ural frequency of thersystemr may‘v be made as 55 high as desired; that is,’ rapid reciprocation, of the sieve may be attained without unduly stress ing the head motion._ Such rapidrreciprocation permits of a large number of short strokesr'per unit of time; so giving ahigh throughput, and 60 also ensuring that the bed is left open or in sus pension 'when the upward stroke of the'sieve be gins. The tension spring'4l has an adjustment 42 to compensate for varying‘ weight of the bed ||, l2. ‘ ' ' 65 The arrangement is such that the toggle oscil lates between the-broken position of Fig; I and the Fig. III position in which the links are more nearly alined' with one another. The result is that the sieve is‘ reciprocated vertically between 70 its lowered position of Fig. I and. its raised posi tion of Fig. III, with a motion which is character ized by "substantially constant downward accel eration approaching a point more than half the downward stroke, sudden retardation, and‘ rapid 75 reversal to upward motion; The machine'has receiving trough 46'on the sieve. ' ' > ' ' Water is supplied to the hutch from an open 40 tank 41 in‘ which'a predetermined water level is maintained as by a ball valve 48.‘ Such level may be varied by adjusting the ball up or down the threaded spindle 49. -A pipe 50 leads from the tank to a point in the'hutch' where the cross section is large so that the in?ow does not in terfere with’the settlement of the concentrates; being provided with a conical'cover 5| to prevent concentrates from falling into it from the sieve. -A non-return valve 52 in the pipe line prevents water being returned from the hutch to the cis tern by the pulsations of the sieve. The pipe 50 is of large diameter to' allow very free movement of water from the tank to the hutch. In the operation of the device, pulp for con centration is fed from pipe 43' into the hopper 44 which feeds it evenly around the‘ annular trough 46 of the sieve. ‘Owing to the vertical re ciprocating movement of the sieve the pulp travels readily towards the periphery of the sieve. The 60 concentrate passes through the bed into’ the ‘hutch; Whilst the tailing ?ows over the lip |4 into thetrough 4. The seal | 9 prevents the'tailing from leaking into the hutch at this point. For the recovery of ?ne concentrates such as that from pyritic goldore, a sieve stroke of from M; inch to 7% inch is desirable, with a frequency of about 2'70 to 300 complete'reciprocations per minute. - V The continued acceleration of the sieve during 70 the greaterpart of its downward movement and its rapidrreversal keep the bed open for a consider able proportion of each period, thus facilitating movement of the concentrate through the bed and minimizing felting of the bed under conditions of V15 3 2,134,154 short stroke and little hutch water. The quick 7 ‘sizes, high proportion and delivered of very a concentrate ?ne pyrite. containing return tends to cause hutch water which has en tered the bed to be rejected downwardly rather than upwardly, thus diminishing consumption of hutch water. Also the interstitial downward cur rents which are laregly responsible for drawing the ?ne grains of valuable mineral out of the ragging into the hutch are set up before compact ing of the ragging has jambed the grains and. rendered them immovable. The level of the water in the tank 41 is so regulated as to check, to the desired extent, the downward interstitial water currents in the bed; such currents, if too intense, ‘tending to carry gangue as well as concentrate into the hutch. The ability to maintain a constant level in the The pyrite entering the circuit with the tube mill feed was 706 lbs. per hour. The amount of jig concentrate produced was 1.35 tons per hour containing 16% of pyrite, or an output of 432 lbs. of pyrite per hour, representing an ex traction of 61.1%. The solids in the pulp leaving the circuit con tained 1.5% of pyrite; mostly ?ne enough to pass a 200 mesh screen. ‘ I claim: 1. In a jig, the combinationof a circular sieve, an adjustable lip seated on the periphery of the sieve and consisting of a ?at metal band pro vided with lugs and clamped around the sieve tank 41 and to adjust such level, together with the prevention of leakage by the seal l9, permit such regulation to be accurately effected. by means of said lugs and yielding ?lling pieces between the lugs. A jig constructed as described with reference to the drawing was arranged to recover pyrite from West Witwatersrand ore. The jig was lo cated in the tube mill circuit and treated the whole of the tube mill discharge after elimination providing a central circular pulp-receiving trough, 20 means for vertically reciprocating the sieve, a therefrom of plus 1/2 inch pebbles. The net sieve area was 45 square feet. The speed was 275 R. P. M. and the stroke % inch. The ragging was iron slag from a faggot heating furnace crushed and graded to pass a screen of 0.187 inch square opening and to remain on a 2. In a jig, the combination of a circular sieve ?xed annular feed hopper comprising an annu lar body ‘and an angular mouth of less diam-‘ eter than the body positioned above the trough so as to drop pulp into the latter, a tangential 25 pipe for passingv pulp into the body so as to pro duce a swirling movement therein and means to receive tailing discharging from the circumfer ence of the sieve. 3. In a jig, the combination of a substantially sieve of 0.034 by 0.281 inch rectangular opening. horizontal, vertically reciprocable sieve carrying The tonnage treated was 1450 tons of solids per 24 hours; or practically one ton per minute. This tongage is equivalent to 32 tons per square foot of sieve area, per 24 hours. The total water entering the hutch was 800 lbs. a mixture of material to be stratified thereen, means for passing liquid upwardly through said per minute, of which approximately 100 lbs. per minute were discharged with the concentrates and the remaining 700 lbs. passed through the 40 jig bed. This is ‘700 lbs. of bed water per ton treated, or 15.5 lbs. per square foot of sieve per minute, or 0.25 cubic feet per square foot of sieve per minute. \ v The feed pulp coming to the jig contained 41% 45 moisture, and the tailings pulp leaving the jig contained only 51.2% moisture. The concentrate screen, and a head motion therefor comprising a rotating shaft, a pitman connected to the shaft " for endwise reciprocation, a toggle disposed sub stantially transversely to said pitman and actu ated thereby, said toggle comprising two links extending from opposite sides of the pitman, one of said links resting at its lower end on a =1 stationary part and the outer end of the other link effecting the reciprocation of the sieve. 4. An apparatus as claimed in claim 3 char acterized by the provision of means for adjust ing said shaft in a direction about at right an gles with the length of the pitman. 5. An apparatus as claimed in claim 3, char was discharged from the hutch at a dilution of _ acterized by the provision of means for adjust 2.22 lbs of water to each pound of solids (or 69% moisture in the pulp). The grading analyses of the feed to the jig and of the clean pyrite separated (by means of hand panning) from the jig concentrate were as fol lows: ing said shaft in a direction about at right an-' gles with the length of the pitman. and means 50 for adjusting the ?rst mentioned link in a di rection about parallel with the length of the pitman. ' > 6. The process of concentrating ore and like granular material consisting in forming a jig Clean pyrite Mesh Tyler - from jig con centrate per cent weight 60 —}é”+1/€" ______________________________ __ _}4II+1/§II_____ H1 bed with said material in a body of liquid, re ciprocating the bed in said body of liquid and in each reciprocation moving said bed downward with a close approximation to constant accelera tion from rest to a point beyond the mid-period of the downstroke stroke, at which it attains its maximum velocity, then suddenly retarding it and. reversing it into the upstroke so that it attains its maximum velocity at less than half the period of the upstroke,-and then moving it 65 with deceleration to the top of its stroke, the It will be noted that the jig successfully dealt with pulp containing particles of widely di?ering movement in each reciprocation being purely ver~ tical. HAROLD HARDY SMITH.