US2144418A - Method and apparatus for sorting or classifying solids - Google Patents

Description

METHOD AND APPARATUS FOR SORTING OR CLASSIFYING SOLIDS Filed April 17, 1935 4 Sheet's-Sheet l Num ATTORNEY Jan. 17, 1939. C, SCHRAMM 2,144,418

METHOD AND APPARATUS FOR SORTING OR CLASSIFYING SOLIDS Filed April 17, 1955 4 Sheets-Sheet 2 ATTORNEY Jan. 17, 1939.` 2,144,418

ND APPARATUS FOR SORTING 0R CLASSIFYING soLIDs F. C. SCHRAMM METHOI'J A Filed April 17, 1955 4 Sheets-Sheet 3 I f 1 I l l 1 ATTORNEY Jan. 17, 1939. 2,144,418

METHOD AND APPARATUS FOR SORTING 0R GLASSIFYING soLIDs F. C. SCHRAMM Filed April 17, 1955 4 SheelzS-Shekl 4 ATTORNEY' yl-atented Jan. 17, 1939 PATENT oFFlcE METHOD AND APPARATUS FOR SBTING 0R CLASSIFYING SOLIDS Frederick C. Schramm, New Orleans, La., assignmof thirty-one two-hundred-iifty-seconds to` Anthony J. Marciante, thirty-one two-hundrediifty-seconds to Vito Manale, thirty-one twohundred-fty-seconds to J. C. Hare, thirty-one two-hundred-iifty-seconds to Peter Ciaccio,

thirty-one two-hundred-iifty-seconds to Dominick Ciaccio, thirty-one two-hundred-ftyseconds to Peter J. Ciaccio and sixty-six twohundred-litty-seconds to Koch Co., Inc. p

Application April 17, 1935, Serial No. 16,8`86 5 Claims. (Cl. 83-94) The present invention relates to an apparatus and a method for classifying, separating or grading materials having different densities or specific gravities and/or of different sizes. .The invention may be usedv in the treatment of any materials in which there are particlesof different sizes and/or densities, such as the treatment of various ores, sands, grains or other pulverulent or granular materials. For the purpose-of illustration, the invention will be defined in connection with the treatment oi metalliferous ores, although this application of the invention represents merely one possible use of the invention.

Among the difiiculties in the metallurgical treatment of ores is that of classification, commonly known as ore dressing. Different ores differ in character and in the manner of treatment. Frequently, the mineral content is freed by pulverization to a point that willA pass through a screen of tWenty-ve minus, but in most cases pulverization must be carried to the point that will permit passage from a fifty to seventy-ve mesh screen, and in other rcases down to a screen of two-hundred mesh. The difficulty in ore treatment lies in the fact that in order to make an economical and proper separation, either by conn centrating tables or through the medium of the iiotation system, the' ore must be delivered to these mill accessories at the proper mesh in keeping with the peculiarities of the ore. Ore classifiers are used, but in operation they are singular in that they deliver the ore in a predetermined cleaner form so that it will pass through a screen of speciiied mesh. Pulverization with the view of obtaining a certain mesh results in a much finer division for a certain percentage, in which case the ore lof more than the desired iineness becomes a total loss.

The object of the invention is to subject the ore'to a classification ystep after pulverization by automatically separating the particles of different degrees of neness, so that those of corresponding neness will be found in the same group, pile, or quantity, in which the metallic particles will be of smaller size than the associated quartz or 'gangue particles from which the metallic particles are derived; to provide an apparatus for the purpose indicated, which is entirely automatic in its operation, of comparatively simple form, and susceptible of cheap manufacture; and, generally, to provide an ore classifying apparatus which will require a minimum of skilled attention when in use.

With this object in view, the invention consists in a construction and combination of parts, of which a preferred embodiment is illustrated in the accompanying drawings, wherein:

Figure 1 is a plan view of the classifying apparatus constructed in accordance with the invention.

Figure 2 is a vertical sectional view through the secondary elevator and attendant discharge screens- Figure 3 is a sectional view on the plane indicated by the line 3 3 of Figure 2.

Figure 4 is a vertical sectional view through the primary elevator and its attendant heating drum.

Figure 5 is a sectional view on the plane indicated by the line 5-5 of Figure 4. 4

Figure 6 is a central vertical sectional view through one of the classifying units.

Figure 7' is a sectional view on the plane indicated by the line I-l of Figure 6.

The classifying operation which the invention is designed to carry out follows the crushing of the ore in a primary pulverizer I0, the discharge II of which is in communication with a hopper I2 formed at the lower end o f a housing I4 in which a bucket conveyor I5 is enclosed and which discharges at the upper end of the housing through a discharge spout I6 in which is positioned the spaced swingingly mounted gate valves The discharge spout I6 enters the heater drum I8 from the side but near the upper end of the latter, so that the particles discharged by the conveyor may drop down through the drum, being passed from one to the other of the downwardly inclined baiiies I 9 which are arranged alternately on opposite sides ofthe drum. The lowermost bafe 19a is shorter than the rest but is suiicient to direct the descending particles through a tubular conductor 20, which carries them to the intake end of a housing 2I in` which is disposed a bucket conveyor 22. The housing 2l, as isthe housing I4, is vertically disposed and the particles elevated by the conveyor are discharged` the screens 25, 26, 21, 28, 29and 30.

A pyramidal hood 3| is disposed above the upper end of the screen 24 and the discharge chute 23 is equipped at its lower end with a distributor 32 formed with reversely disposed spiral ribs, so that the particles oi ore will be distributed over the full lwidth of the screen.

To provide for dust removal, the casing 2| which houses the secondary conveyor. the hood 3| and the heating drum I8, are all in communication at their upper ends by means of the tubular conductors 33, 34 and 35 with the intake of an exhaust fan 36, the exhausaianbeing of the.. center-intake, peripheral-discharge Vfor 'I'he drum I 8 is heated by means of a burner 31 disposed adjacent the nre door 38 with which the drum is provided. An air regulating means 31a is provided immediatelibelow the burner, consisting of xed and movable perforated plates in which the perforations in the two may be'brought into and moved out oi registratin. Thus, the desired air may be supplied to the burner and the desired intensity of heat in the drum thus secured.

The several screens 24 to 30 inclusive discharge into ilat hoppers 39, that hopper associated with the screen 24 discharging into a tubular conductorv 40 which is in communication with the secondary pulverizer 4I, the discharge of which is tapped into the discharge II of the primary pulverizer by means of a tubular conductor 42. Thus particles of too large size to pass through the screen 24 are reground by being subjected to the action of the secondary pulverizer 4|.

'I'he hoppers 39 of all of the screens other than the uppermost screen 24 are in communication each with a classifier by meansl of tubular conductors 43. These classiiers are subjected to an air current produced by an exhaust fan 44 of the center-intake, peripheral-discharge form, with whose intake a manifold 45 is connected, into which each of the classiers is tapped. Structurally, the classifiers are identical, so that the description of the one will suiiice for all.

The tubular conductor 43 discharges into a hopper 46, which in turn discharges through a lateral intake 4'I into a stand pipe 48, the lower end of which is closed by a pair of adjustable gate valves 49 actuable by means of exteriorly controlled handles, not shown. An air current passes up through the stand pipe 48 and the amount of air passing is determined by the degree to which either or both of the gate valves 49 are open. The stand pipe is in communication with an inverted conical shaped ore chamber 50 through the side wall near the top, and the discharge end of the stand pipe is arranged tangentially of the ore chamber so that there will be a swirling action of the air entering thechamber which is provided with an access opening in the top wall closed by a removable cover 5I. An air intake at the top of the stand pipe Vis provided by means of a lateral connection 52 in which is disposed a manually adjustable valve 53, the degree of opening of which determining in part the amount of air entering the or'e chamber.

The ore chamber is provided at the apex of the cone with a discharge spout 54 in which are disposed a pair of swingingly mounted gate valves 55. The spout 54 discharges into a hopper 56, which in turn discharges through a lateral inlet 51 into the cross-sectionally square tubular member 58, the latter being equipped at its lower end with a pair of swingingly mounted gate valves 59 identical, in form and manner of operation, with the gate valves 49. The member 58 is stepped at its upper end, the several steps increasing in size, and it is provided with downwardly disposed discharge mouths 60 arranged at the plane of each step. These discharge mouths are intended to discharge into suitably placed receptacles not necessary of illustration. 'At its upper end, the member 58 is tapped into a tubular conductor 6|, one end-of which enters the ore chamber 50 through the top and terminates in a flaring intake mouth 62, that portion ot the [conductor 6| within the ore chamber being axially coincident with the latter and being provided adjacent. the top of the chamber with a series of perforations 63. Since the ore chamber is subiect to a passing current of air which leaves it through the conductor 6I, the perforations 63 are provided to eliminate a still air zone in the ore chamber and thus dispose of dust that might otherwise accumulate in the top of the ore chamber. Beyond (the point Where the member 58 connects with it, the tubular conductor 6I is increased in diameter and enters the detritus receiving drum 64, the discharge end being downturned as indicated at 65. The detritus receiving drum is formed with aconical bottom 66 and with a discharge spout or mouth 61 positioned at the apex of the cone and provided with a pair of swingingly mounted gate valves 68.

'Ihe ore receiving chamber on its conical side walls is provided with a series of impact vanes 69 with which the passing ore is brought in contact.

Each classifier is arranged to make appropriate subdivision of the particles received from its associated screen.

In operation, the ore is placed in the primary crusher, from which it passes to the primary conveyor I4 and thence down through the primary heater drum I8 from which it is transferred to the secondary conveyor and from the latter to the uppermost screen 24. Such particles as will not pass through this screen enter the at hopper 39 associated with that screen and are transferred 4through the tubular conductor 40 to the secondary pulverizer 4|; from which they are returned to the primary conveyor and reach the screen 24 in the same manner as formerly but, being finer, will pass through this screen as will the particles which were initially ground ne enough for this purpose. Each screen will gradev the particles according to the mesh employed by the screen, and the several screens are of progressively ner mesh. Such particles as pass through the uppermost screen 24 are transferred to the classier, through which there is a continuous current of air passing by reason of the operation of the fan 44. In each classifier the valves 49 are adjusted to permit the desired volume of airl andthe particles which reach the hopper 46 enter the stand pipe 48 in the rising current of air and are transferred to the ore chamber 50 tangentially of the latter and are whirled around the same, dropping out through the discharge spout 54 into the hopper 56, the gate valves 55 opening only during discharge through the discharge spout and therefore preventing any material intake of air into the ore chamber through the discharge spout 54. The particles, after being subjected to the operation of the ore chamber in which dust is shaken from them by impact with the vanes 69 and having been transferred to the hopper 56, are then transferred into the member 58 through the lateral intake 5l. The desired volume of air passing upward through the member 58 is secured by proper adjustment of the gate valves 59 'and the particles are raised by this current, the

heavier particles dropping through the discharge mouths 60 of the lowest step, lighter particles passing through the discharge mouths 60 of the next higher step, etc. In the member 58, the particles actually iloat in the air and the metal particles being heavier than the quartz or gangue particles, metal particles of corresponding weight will pass through corresponding discharge mouths 60, as will quartz particles of corresponding weight. But the quartzparticles of weight corresponding to the metal particles will be of larger size than the latter s'o that through corresponding discharge mouths 60 there will be passed metal particles of similar sizes and quartz particles of larger size, the larger size quartz particles being the same weight as the metal particles.

While the screens will grade the particles according to size, the operation carried out in the member 58 will grade them according to weight, so that finer metal particles will be found associated with larger size quartz particles, which will make the nal separation an .easy matter even if carried out by a wet process.

All the detritus will be passed into the detritus drum 64 through the tubular conductor Bland discharged from said drum through the discharge SPOut 61.

Having described the invention, what is claimed as new and useful is:

1. The method of separating solid material which comprises pulverizing the material, drying the pulverized material, grading the material according to size, re-pulverizing the largest particles of the material and mixing the repulverized material with the material pulverized in the rst step, grading the material according to size, subjecting particles of material of similar size and moisture content to a current of air of a strength-to liit the lighter particles from the heavier particles, and regulating the strength oi the current of air to control the separation.

2. In a separating apparatus, a pulverizer adapted to receive material to be treated, a drier connected to the discharge of the pulverizer, a grading apparatus arranged to receive material from the drierand adapted to sort the pulverized material according to size, a. secondary pulverlzer connected to said grading apparatus and adapted to receive oversize material rejected by said grading apparatus, said secondary pulverizer having its discharge connected to the drier, and a series o! pneumatic separators .connected to said grading apparatus, each separator being adapted to receive material of uniform size and uniform moisture content from said grading apparatus.

3. Ina separating apparatus, a separating chamber comprising an ,inverted substantially conical casing having a discharge chute at its lower end and an inlet adjacent its upper end, vanes arranged on the inner walls of the casing, a cover for said chamber, a conduit extending through the cover of the chamber axially thereof and down into the chamber, a vertical separating column connected at its upper end to the conduit exteriorly of the chamber and connected adjacent its lower end to the discharge chute of the chamber, and means to induce a current of air in the conduit.

4. In a separating apparatus, a separating chamber comprising an inverted substantially conical casing having a discharge chute at its lower end and an inlet adjacent its upper end, vanes arranged on the inner walls of the casing, a cover for said chamber, a conduit extending through the cover of the chamber axially thereof and down into the chamber, a vertical separating column connected at its upper end to the conduit exteriorly of the chamber and connected adjacent its lower end to the discharge chute of the cham. ber,

means to induce a current of air in the conduit, said column having stepped portions in VAwhich the steps are of progressively increasing diameter, the stepped portions having discharge nozzles.

5. In a separating apparatus, a separating chamber comprising an inverted substantially conical casing having a discharge chute at its lower end and an inlet adjacent its upper end, vanes arranged on the inner walls of the casing, a cover for said chamber, a conduit extending vthrough the cover of the chamber axially thereof Aand down into the chamber, a vertical separating column connected at its upper end to the conduit exteriorly of the chamber and connected adjacent its lower end to the discharge chute of the chamber, a tank of large cross sectional area connected to said conduit, and an air current inducing means communicating with the tank to induce a current oi air in the conduit, chamber and column, the tank serving to insure a uniform current of air due to its large capacity.

FREDERICK c. scnnAMM. 50

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