US1870371A - Classifier - Google Patents

Description

Aug., 9, 1932. 1 A. D. MARRIOTT 1,870,371

CLASSIFIER Filed 001;. 17, 1930 2 Sheets-Sheet 1' awuewboz a ALEXANDER 0. MARRIOTT Aug. 9, 1932. I A. D. MARRXOTT CLKS'SIFIER Filed Oct. 17, 1930 2 Sheets-Sheet 2 gvwewco'c ALEXANDER!) MARE/077' QHIMMQA;

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Patented Aug Q, 3932 ALEXANDER D. MARRIOTT, 0F DENVER, COQQRADQ, ASSIGNGR, BY MESNE ASSIGN- DELAWARE MEETS, TO THE D0313, COMPANY, INC., OF NEW YQBK, N. '31, A GORJEORATIQN @IF cnasismma cooperating tanks have been employed, the

upper one, known as the primary chamber or bowl, receiving the material and feeding the settling particles therefrom down through a central bottom opening into a secondary compartment. F or such classifiers the feed from the bowl to the undercompartment has been by gravity, the -material being again classified in the undercompartment so as to throw the lighter particles into suspension.

By an upfiow of the solution, the particles in suspension have been carried back into the bowl while the heavier materials settled in the secondary compartment have been removed therefrom by mechanical means, such as rakes.

Perhaps one of the greatest difiiculties encountered in use of such classifiers, has been the interference between the large mass of settled material passing downwardly through the constricted opening at the-same time par ticles in suspension are passing upwardly through the same opening. The present invention seeks to overcome this interference and resultant congestion.

Another drawback to classifiers as heretofore used is the loss of much material passing outwith the overflow from the bowl as a result of the proximity of the inlet and overfiow and critical nature of the particles which follow the overflow current rather than settle as they should. The present invention seeks to'retain particles of such critical nature for reclassification and discharge. i

In order to operate the classifiers'as heretofore constructed. it has been necessary to introduce a considerable additional fluid,

partment so as to create a flow from the secondary compartment to the primary chamher or bowl. This back-wash obviously increases the dilution, and in ,many instances this type 01 classifier could not be used, as w increased dilutlon 1S detrimental or ob ectionable from the standpoint of the resultant products. An inventive concept in the present case seeks to avo'd or limit dilution and yet obtain the advantage of primary and secondary settling.

Construction of previously used classifiers has included elaborate means for feeding the material into the primary chamber, utilizing heavy and expensive feed wells, baiiie rings and plates designed to overcome, to some extent at least, currents in the chamber created by the introduction of the material. The disclosure set forth herein eliminates those parts, and simplifies construction, use and operation of this type of classifiers.

Also, heretofore it has been difficult to obtain a classifier in which the material may be classified into several categories, such as coarse, intermediate and fine particles, so that one purpose of this invention is to devise a construction to obtain, generally as well as specifically, classification into two or more divisions in the one apparatus.

With the specific problems mentioned above in View, and with the objects already stated in mind, with other objects and advantages as'may more clearly appear in the following description, one embodiment of the invention is illustrated in the accompanying drawings in which like numerals of reference indicate similar parts throughout the several views, and in which t Figure l is a plan of a classifier constructed in accordance with the present invention;

Figure 2 is a sectional view taken substantially centrally across the bowl and longhtudin ally with respect to the secondary compartment, omitting the central partitions;

Figures 3 and 4 are detail sectional views of the floor of the pan and adjacent feed means on lines 33 and H respectively of Figure 1; and

Figure 5 is a sectional view on the line 5-5 of Figure 2 taken through the floor of the Joke or oiher conveys merggence 33o ripheeiigl of seici of the meiveriai will pass through one of the semen pan. end. the Bottom of secondesy comgasr 'reeiiii "the specific embodiment of inven- Szicn iiiustrsieei sei drawings, she iassic construction shown provides ivvo settiing senks'ideiiiiiiedi as seicaiimg chamber or or pan 1 emit a secondary settling compartment 2 one end which underlies she pee in The set'si-ingg compsriment is subdivided ineo' iorigiiiiciiiiei uniis 3, 3 by perizitioiis The coiisirucsioii is siicii chat o she s s ied riie-t-eriai primary r can so eiishe: one or both units of she secorieiesv com o izmesi so i u ers the sen es vviii ice iuiiy ezpisiiiee eiiieiser,

ehiy c" cr ses e circuier he bottom or desk i h is iriciiried so that e fluid e pee win cover or sec merge she iow I: oi the exeose she ripper poi ions of: hoshis ri noes or non-sea mergeci portion :i coris'tiiiiuing cireis A J? .v M M in me ior movie a ;-.v r p u {in our, c119 lower pew, oi see more sureeivmere the q i a a e se eo. mesemei is emerged 1 cs meioeri i eischsrge su ing this rs'ize assumes 'ion suiosssiitisiiy :iiemeiser she "with e piu eiii v oi scoop-hiss hiscies 5 she seripiier iiereoi he or seek oi ie Thee v re carried by inner and outer coerce 6, 7 re specfsw eiy, inner wig be eonoeciegi ioy spokes 8 "co e cem: i i with suiteieie his driv s as Wiii she of ishe a means such s motor sui iig sgeeci. rechiccioii cor :oe underssooci hv those skiiic "it is to he iio'sefl shes 'hisies ii are ensireiy submerged 2250' he hctioro ihe pen below the normal ievei of the iiiiici therein so as to receive the settling; meierieis, end es the oi-mics are revolved move the fluid in the pen they gather as remove therefrom a-quantit v off she sescieci riieicriei, carrying the same along an ercrieie path over the deck oifihe pan outof she iiqsiri into the exposeci or (irainage area, The material thus eieveted end drained is iheii discharged.

In the presexit showing, diischerge of the emerged materiel hec so sohmergeiice may be effected to the secoi'iiery compartment, for

which purpose on upper or rion-sohmergeci the first unis sired.

epertures and file remaining portion of meteriai Wiii iii-op through ihe other opening. this means, she material is distributed ioeuween the two units of the secondary compertinent. Preferably the apertures 11, i are at ciifierent radial ciistsnces from the center of rotation of the rake, out cosh Within she path of movement of the biecies, zinci' as shown, the aperture 11 which is passes first by any given hisde is next the outer periphery of she raise, Whereas the second aperture 12 is nearer to inner ringof she mice" Passage of a blade across the first or u er eperizure resuis's in iii materiel :ieeiess end; ouiei' end of she circpping through to of the secondary compermens, ei'ter Which/she biecie continues its revoiuiion comes to seccnci or lower sper the remeinirig' materiel carried Werci by the inner end oi 'rzhe biscie through to the secorici unis or ice secon compartment.

if ciesired, either or both 0 11, 1:23 he cioseri so ss p sage of the material iiiso either o the ccmpsrtmeiii For iihisy' yurposes, these specialises shown as i331 ingswinging gates respectivei giv oted fietwise heneeih the iocoiom or deck of the These g s'tes iris be oe e or ciosed will 30 o iii sin ciessiiic In event hem gates cicsecipiiischerge oi the material "mined through s11 aperture any given hiee after passing closed apertures. exit aperture preferably of e size such that eii 'Zeriai from the hia'zies Wiii drop same. closure, such as gate 16, be provided for this exit aperture also, sslci being shown pivotec. iiebvvise against oni dersicie ofthe bottom or deck of th an. is to he noieti their; iliis exit openiis as; e part of the pan not overiying secondary compartment so that the discharged *ne'terisi "feiiiiig iheretnroughwiii not enser irie eomyartment but may conveyed off or other- Wise hencileoi as iounci moss expedient.

The seconery compersmet, es shove indicateci, preferably comprises e, pair of simiisr units, and these units are shown side by side in parallel relation, both sloping; from s position under the pen to a position re moved a considerable distance ietemiiy from 125 the panami Weii shove the normei iiuici'ievci therein. This part of the structure is in most part oici in the art, reference being had '50 Patent 1,292,237 ofJenuery 21, 19'

O ,0 ZS- sued to Biomfieici "for s oi'eteiied description thereor. in generei, each unit is in Hoe form or an inclined trough in which a mec amceilv ea set,

ll, 18, one, as 17, near the discharge end and the other, 18, toward the lower end, both hangers being supported by interconnected bell cranks i9, 20 respectively, the upper one 19 of which has a-rocker lever 21 depending therefrom for actuation by a cam 22 driven through suitable reduction gears by a motor 23. This motor, with attendant reduction gears and shafts, may obviouslybe common to the several units as indicated inthe drawings. The structure as above outlined obtains an odsetting movement of the entire rake toward and away from the bottom of the trough. Reciprocation of the rake is obtained by a crank-operated pitman at, this reciprocal movement, combined with the odsetting movement, resulting in an orbital large particles have been raked to a central till aperture where they have dropped. into the secondary compartment, the fine particles using that same aperture but in a reverse direction to return from thesecondary compartment to the primary chamber. Such construction has proven to require an unnecesl.

sary expenditure of power, time and eiiort, in that all of the heavy particles have to be raked in both tanks. By the present invention, this action, is greatly simplified Means are provided herein for introducing the ma terial to be treated into the secondary compartment first so as to subject the material immediately to the stirring action of the reciprocating rakes to throw into suspension both the fine particles and some intermediate or critical particles. Thus, the heaviest particles, not entering the primary chamber at all, reduce interference and congestion heretofore existing in that chamber.

Passage of the "fine particles andcritical partiolesin suspension is permitted to the primary chamber through upfiow openings 25, 25 providedin a submerged portion of the deck of said primary chamber. As shown, the said openings are over the lower ends of the units, one for each unitfand between the path of the blades in the pan and the center of the pan. By this arrangement the rising solution from said upflow openings will have no disturbing effect on particles settled into the blade area, nor will that settled material interfere with the upfiow from the secondary compartment. It will also be observed that the entry of the solution and particles to the pan is by a difierent opening than that through which the material is discharged therefrom. This feature is important, as it reduces interference and eliminates congestion. The efiuent or outflow of the fluid with fine particles in suspension is obtained by a launder 26 preferably overlying the area of sub merged revolution of the rake blades. This arrangement directs such current as exists in the hind to'ward the area of the blades so that the settling particles will encounter the blades and be discharged thereby. However, it is desirable to minimize the current in the fluid as much as possible, particularly where the fiuidpasses over the weir 27 to the launder, since a large-volume or a swift current passing over a weir will carry correspondingly larger particles, and it is desired to permit escape or fine particles only. As shown, the discharge launder 26in a semicircular trough spaced inwardly from the periphery of the pan for he deeper portion thereof. The two upper arcuate' edges or" this trough or launder are in a common horizontal planeat substantially normal fluid level in the pan and constitute weir 27-above mentioned. Since both edges of the launder are free and within the pan, the fluid in the pan will have access for discharge purposes to both sides of the trough thus reducing the discharge velocity over the said sides or weirs to one half of the velocity which it would have were only one side oi the trough accessible to the tluid as a weir. The bottom of the trough preferably slopes downwardly to a middle part of its length and there discharges through a sluiceway28 through the side of the pan. Thissluiceway 28 is obviously a passage laterally from the trough but closed with respect to the fluid content of the pan so as to prevent escape of the fluid except by way of the weir, launder and thence into the sluiceway,

From the above description, it will be un' derstood that, contrary to previous practice,

the material to be treated is introduced in-- i itially into the secondary compartment or classification zone rather than into the primary chamber. According to the present disclosure, this initial introduction is above the lower end of the secondary compartment, between the upper apertures 11, 12.a nd lower openings 25. By this arrangement, the lower ends of the rakes and rake compartment are not likely to become congested, and interference by the introduced material with upfi'ow through the lower openings 25 ofthe pan is avoided.

A. pipe or conduit 29 is shown at one side of the secondary compartment illustrative of means for conveying the material to be treated to the desired position for introduction to the compartment. This conduit is shown entering beneath the pan. between the lit Elli

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" secondary grinding where it is 'ablc means (not shown) may pan and compartment in a direction longitudinally of the compartment. At a proper position under the pan, the conduit is directed laterally so as to be positioned over the compartment, this lateral portion being shown as a double conduit, one portion of which extends to a position over the middle of the first unit where it has a discharge opening 31, and the other portion 32 ot the conduit extends on over to the second unit with av discharge opening over the middle of that unit. These two conduit portions 30 and will therefore split the feed or supply oi material and discharge part there of into each unit for classifying.v Means may be provided in connection with the sup ply conduit to permit feed to both units or to only one unit. ()ne such means is exemplified by a valve or gate 3 1 in the double portion of the conduit which valve may lie across either portion of-the conduit or may stand in a neutral position. Obviously when the valve stands across either portion of the conduit, flow through that portion is stopped i but flow through the other portion cont1nues.

\Vhen the valve is in neutral position,'flow of material is permitted in both portions of the conduit to both units.

A second feed conduit 29 is provided at the outer side of the unit 3 of the secondary compartment for an outside source different from that which supplies the feed conduitQS). This is'especially useful in closed circuit, primary and desirable to operate the unit 3 in closed circuit with a secondary mill. Where the materials handled in the dilierent units Sand 3 are different, as in primary and secondary grinding it is preferable/to arrange the diilerent units with diiierent slopes. For example, a slope of 3 inches per foot for unit 3 and a slope of 2 inches per foot for unit 3.

Since the material is introduced into the secondary compartment, and since only a part of that material settles so as to be raked out, there will be an excess of material for obtaining an upflow from the secondary compartment to the primary chamber. The

' classifier is therefore capable of operation without introduction of any backwash, which is frequently an important consideration, especially since the velocity over the discharge weir is a function of the amount to be discharged and the loss of desired or critical particles is a tunction of that velocity. However, for obtaining dilution or backwash when needed, a spray pipe is provided across the secondary compartment at 1 position intermediate the upper or discharge end thereof and the pan. Any suitbe employed to regulate the supply of backwash supplied by this pipe as will be understood.

To separate the discharge of intermediates feeding the unit 3 from flowing from the primary compartment through openings 11 and 12, from the openlugs 25, a bafiie 36 is arranged to extend down into the secondary compartment between the upper group of openings 11 and 12 and the lower group of openings 25. This provides a clear zone of back-wash water through which the material of intermediate size trom the primary compartment is dropped into the secondary compartment.

ilfhere desirable,'the openings 25 at the lower portion of the primary compartment may be omitted and the flow from the secondary compartment to the primary compartment thereby caused to take place through one or both of the openings 11 and 12.

iihis improved classifier is adapted for use in several ways. in any event the material to be treated is introduced into the secondary compartment for initial classification. With the use of two units for the secondary compartment, the material may be introduced intc only one unit or into both units. Supposing the material is introduced into both units, with the conduit valve in neutral,itwill be seen that the coarse settlings will then be discharged over the top of both units and the particles thrown into suspension will pass up through both openings 25, 25 in the lower part of the bowl. The pan will then classify between fine and intermediate particles. Nowif both gates to the upper apertures 11,12 in the pan to the compartment are open, the intermediate particles then return to the two units and will discharge in most partwith the larger particles. Thus,

the classifier operates to separate into two classifications. If, on the other hand, initial supply of material is to only one unit and discharge from the only, classification three ways will be efiected, that is, the first unit will discharge the coarse particles, intermediate and fine will pass up to the pan where thefine'passes out with the overflow and the intermediate, is discharged to the second unit. In the second unit, the product is reclassified, returning any fine particles to the pan, and thus a very clean intermediate product is obtained. Should the character of the intermediate product not be needed so perfect, it may be caused to discharge from the exit aperture 15 by opening the gate thereto and closing the gate to the second unit.

pan is to the other unit" For closed circuit, primary and secondary grinding mill, while suitable provision is made for returning the discharge from the I to the upper end ofsecondary units 3 and 3 primary and secondary grinding mills respectively. Thus under such operation, discharge from the primary mill will be fed di rectly into unit 3 of the secondary compartment where a relatively coarse separation is made, the coarser material being raked to the upper end and returned to the primary mill while the finer material flows to the primary compartment. The material of intermediate size settled out in the primary compartment is discharged therefrom through opening 12 into unit 8 of the secondary compartment, thence raked to the upper end and conveyed to the secondarymill from which after further grinding it is fed directly into unit 3' of the secondary compartment, from which the finer material flows through opening into the primary compartment, the finished product overflowing the primary compart- 2Q ment.

Obviously other detail changes and modifications may be made in the construction and use of the improved classifier constitutingthe present invention, andit is to be 25 clearly understood that the invention is not limited to the exact structure or operation shown or described, except as set forth in the following claims when construed in the 7 light of the prior art.

Having thus described the invention, I claim 1. Apparatus of the class described having a classification compartment, a sedimentation compartment forming a top for the lower end of said classification compartment and inclined in a single plane with respect to the liquid level therein, an inlet from the classification compartment to the sedimentation compartment located in the lower end of the classification compartment, an outlet from the sedimentation compartment to the classification compartment, and rotary means for conveying sedimented material from the sedimentation compartment to said outlet.

2. Apparatus according to claim 1 in which the conveying means convey the sedimented material upwardly against gravity.

3. Apparatus of the class described having a plurality of separate classifying compartments, a single sedimentation compartment superposed upon said classifying compartment and inclined in a single plane with respect to the liquid'level therein, an inlet to said sedimentation compartment in the lower end thereof from said classifying compartments, an outlet in the upper part of said sedimentation compartment to each of said classifying compartments, and means for controlling exit of material from said sedimentation compartment through said outlets.

4. Apparatus of the class described having a raking classifier, a material feed therefor,

' a sedimentation compartment superposed on one end of said classifier. provided with an inclined partially submerged deck, means for means for returning said cleansed solids to re submergence in said classifier through said discharge.

.5. Apparatus of the class described having a raking classifier provided with a clean sand discharge, a material feed therefor, a sedimentation compartment communicating with said classifier having a partially submerged deck, an overflow therefrom for fine .inaterial, means for cleansing sedimented material in said compartment by conveying the material up said inclined deck to non-submergence, and means for returning the cleansed material to re-submergence in said classifier.

6. Apparatus of the class described having a raking classifier, a sedimentation compartment communicating therewith through the medium of an inlet from classifier to compartment and a discharge fromcompartment to classifier, a launder for feeding material initially to said classifier located between said inlet and discharge anda baflie to keep separated the discharge from the sedimentation compartment and the feed to the classifier.

7.. Apparatus of the class described comprising a raking classifier, a deck superposed on one end thereof, a submerged inlet from classifier to deck, a non-submerged outlet from deck to classifier and means for conveying material on said deck from said su merged inlet to said non-submerged outlet.

8. Apparatus of the class described having a raking classifier, a pan superposed on one end thereof, a submerged inlet from said clasclassifier to deck, a non-submerged outlet from deck to classifier, means for conveying material on said deck from submergence to nonsubmergence, and means for returning said non-submerged material to re-submergence in said classifier.

In testimony whereof I aifix my signature. ALEXANDER D. MARRIOTT.

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