US2171674A - Classifier - Google Patents

Description

C. J. SCHIFFER LE CLASSIFI ER Sept. 5, 1939.

Filed Feb. 12, 193'! INVENTOR CHAPL5 J'JCH/Fl-ZELE BY d W H/fi ATTORNEY Patented Sept. 5, 1939 UNITED STAT S mime PATENT OFFICE cisco, Oalif.

Applicationr'ebruary 1'2, 1931,Seriai No. 125,452 2 Claims. (Cl. 209 157) A'nother object is to provide a classifier which may be readily and aceuratelif adjusted for effect ing a separation of solid particles i'n accordance with a desired classification; and for adapting the device foruse in the treatment or various kinds of materials. 1

Another object is to provide a classifier which will facilitate the recovery of values collected by 20- the rifiies of sluice boxes and similar devices, and which will effectively trap and retain precious metals, amalgam, mercury, and similar values Washed therefrom. I

The invention possesses other objects and features of advantage, some of which, with the force going, will be set forth in the following description of my invention. It is to be understood that I do not limit myself to this disclosure of species of my invention, as I may adopt variant 30 embodiments thereof within thescope of the claims.

Referring to the drawing: Figure 1 is a vertical mid-sectional view of a classifier embodying my invention, portions be- 35 ing broken away;

Figure 2 is a plan view, partially in section, of the embodiment shown in Figure 1, parts being broken away;

Figure 3 is a sectional view of the delivery end of the classifier conduit taken in the plane of the line 33 of Figure 1;

Figure 4 is a sectional detail of a suitable fitting through which a flow of liquid may be introduced into the bottom of the hopper.

My invention is primarily intended for collecting gold, platinum and similar valuable materials from placer sands, crushed ores and similar materials, very large quantities of which must be handled with extreme economy in order to obtain a profitable recovery of verysmall quantities of the valuable substances.

ing such substances is frequently complicated by the factthat the values are present in various conditions which resist the ordinary methods of 5 5; classification and recovery heretofore commonly The problem of recoverused; For example, gold may be coated as inth case (if rusty gold, or it may be in acom bined fdi'lnl whichresists or completely precludes amalgamation iii the ordinary sluice boxes. Farticles of value may be enclosed in grains 01 quartz or other gangudwhicli are lost with the w'aste'mate'r'ian carried over the rifiles of the; ordinary types of classifiers; or the size, shape buoyancy of particles, as in the case of fine flake gold, may be such as to cause the values to be earned over the riflles'. The classifier at my present inviitioil is particularly useful for concentratiiig" such values into a relatively small bulk which can be economically treated to effecta complete recovery of the values";

Interms of broad inclusion, tii classifier Of my invention comprises a conduit arranged t6 receive a flow of liquid carrying particles of sol-id matter such as placer sands, crushed ores and similar materials to be classified in accordance with their specific gravity, siie, shape and related physical properties. The conduit is provided with a wide shallow horizontal inlet and a deep narrow vertical outlet. The cross sectional area is madesubstantially equal at all points along the length of the conduit so that thevelocity of a stream flowing through the conduit wi l be substantially uniform and free of cross or eddy currents along its entire length. The depth of the stream increases progressively along the length of the conduit, and as a consequence there is a gradual upward displacement of the major portion of the flow relative to the bottom of the conduit.

Particles of solid material carried by a stream of water flowing through the conduit tend to follow a substantially straight course except as they are affected by the opposing forces of gravity and the upward displacement of the flow due to the shape of the conduit. Under these conditions, the heavy particles tend to settle out and form a stratum across the bottom of the conduit; Particles of lighter or of more buoyant character settle out to lesser degree; and the rising flow of water tends to lift those particles and carry them. over the heavier particles at various depths in. accordance with physical properties of the individual particles. By the time a given volume of water flows from the inlet to the outlet the particles carried thereby will have arranged themselves in zones; and will have become segregated with other particles, having similar physical properties, in a plurality of strata extending across the width of the conduit at various depths.

This stratificatio o i113? 7 01 P l l qlfie'i'fi trolled by adjusting the inclination of the conduit. Such adjustment regulates the velocity of flow, and varies the degree of the rising movement of the stream relative tothe bottom of the conduit; and also varies the amount of vertical movement of the particles while being carried along the length of the conduit. 7

Means are provided for selectively dividingthe stream issuing from the conduit into a pluralityof portions corresponding to selected strata of the solid particles carried thereby; and for delivering the stream portions into separate laundcrs, whereby the classified products may be directed to desired points where they maybe further fore it enters the classifying conduit,

In terms of greater detail, and referring particularly to the preferred embodiment of my invention illustrated in the drawing, the classifier of my invention comprises a conduit I having a wide shallow inlet 2 and a narrow deep outlet 3. The sides of the conduit converge toward the 7 outlet and are of progressively increasing height from the inlet tothe outlet end of the conduit. Therelation of the Width anddepth of the conduit is such' that the cross sectional area is substantiallythe same at all points along the length of theconduit. This causes a stream of water passing through, the conduit to flow at substantially uniform velocity along the conduit without setting, up objectionable eddy or cross currents; and also causes a rise of the flow relative to the bottom of the conduit.

The shape of the conduit I, and the proportions of its dimensions, may be varied within rel atively wide limits. In general, the width of the inlet. should be from about ten to fifty times its depth; and the outlet should have, a depth from two to ten times its width. Satisfactory results" have been produced by a conduit of the form illustratedin the drawing, the inlet being'32 inches wideand 7 inch deep. The outlet has a width of about 1% inches for a distance of about 2 inches up from the bottom. Above that point, the sides may flare to a width of about 5 inches so as to reduce the height of. the outfiowi'ng column of water. A conduit of this form having a length of about 8 feet has been found to be satisfactory. The length may be varied within wide limits, a greater length being desirable where the differences in the physical properties are slight,v

and a lesser length being satisfactory where the differences are great.

The conduit I may be madeof any suitable ma terial, sheet metal of a thickness of about 5% inch and having smooth welded joints being preferred. The bottom of the conduit is preferably flat, while the-sides and top of the conduit are curved to obtain the desired uniform cross sectional area. The top is preferably closed, but maybe left open in installations where the inclination of the con-.

duit is such that the flow of. water does not rise above the level of the inlet 2.

The outlet end of the conduit I is provided with one or more delivery spouts 6 arranged to divide 1 the. outflowing stream into, a plurality rof por- 75 tions each containing a desired stratum of the solid particles. The spouts B may be in the form of a plurality of nested troughs carried by arms I mounted upon suitable pivots 8. The arms I permit the spouts 6 to be adjusted to desired positions relative to the outlet 2, suitable securing means such as a stud 9 and wing nut I0 being provided for holding the arms I and spouts 6 in adjusted-position. I

The spouts'li are preferably adjustable relative to each other so that each may be positioned with its bottom spaced a desired distance above the bottom of the next lower spout. Studs II extending through slots in the sides of the inner spouts 6, and provided with wing nuts I2, provide one'simple means for securing the spouts in adjusted relation, but any other suitable securing means may of course be substituted if desired.

The spouts are of progressively greater lengths, and the outer ends of the spouts 6 are arranged to deliver the respective portions of the stream into separate launders I5. The inner end of each spout 6 is provided with a thin edge for dividing the outflowing stream at a sharply defined line between adjacent strata.

Material is supplied to the conduit I from a launder I6 which may be the sluice box of a dredger, or a tail race or other launder arranged to deliver a flow of water and entrained solid material into the conduit. The material is supplied under sufficient head to insure that the stream will'rise andsubstaritially' fill the conduit lat its outlet end. This is preferably accomplished by means of a hopper I1 into which the stream fiows through an opening I8 in the bottom of the launder I6. A screen I9 may be mounted over the opening I8 to prevent coarse gravel and refuse from entering the hopper.

The conduit l is connected to the hopper I! near its lower end by means of a flexible joint permitting pivotal adjustment of the conduit for varying its inclination. The flexible joint may be a pad'ZI of rubber or other yieldable material secured around the outlet 22 of the hopper. The

inlet end of the conduit I may be secured to the pad 2| by means of a flange 23 through which rivets or other suitable securing means may be applied.

The outer end of the conduit I is adjustably supported in any convenient manner, as for example by a suspension rod 24 provided with a turn buckle 25 by which the outlet end of the conduit may be raised or lowered to obtain a desired inclination.

Such adjustment of the conduit I permits an effective control of the Stratification of the solid particles carried by the stream flowing through the conduit. This control is due in part to the change in. velocity of theflow; and in part to the difference in the degree to which the flow rises above the inlet, and the difference in the degree-of verticalmovement of the particles. Thus, if the conduit has little 'orno inclination, the heavy particles have only a short distance to settle b-efore'reaching the bottom of the conduit, and are carried along as a dense strata across the bottom of the conduit. Lighter and more buoyant particles are carried upwardly by the rising fiow'of the water and arrange themselves in various zones depending upon their physical properties. The separation of the particles under such conditions, particularly the heavier particles forming th'elower strata, is somewhat in the nature of the 's'o-caued hindered settling, theparticles being carried in a dense mass within which the particle-s move relative to each other.

As the downward inclination of the conduit l is increased, the heavy particles have farther to sink, and there is a lessening of the degree to which the flow rises above the inlet. As a result, only the particles of greatest specific gravity and least buoyancy will reach the bottom strata, and other particles will arrange themselves in higher strata in accordance with their obvious properties. Under these conditions, separation of the particles occurs more in accordance with the principles of free settling wherein each particle is free to assume its proper position without material interference by other particles.

The conduit may be adjusted to any desired inclination ranging from substantially level, or even slightly upwardly inclined, to a downward inclination such that the stream does not rise above the inlet. In all positions of adjustment, classification is effected as a result of the action of the stream of water flowing through the con duit without the introduction of water from a separate source.

The various strata of the classified particles are separated as they leave the conduit l by the spouts 6. Since the outlet is narrow, the various strata will be relatively deep, and the spouts 6 may be readily adjusted to separate the strata at points which will insure the retention of substantially all of the values in one or more portions of relatively small volume containing a minimum of waste material.

In general, the major portion of the values will be carried in the lower stratum and. may be delivered directly from the conduit l into a launder for directing that portion of the stream to a place for further treatment. The narrow portion at the bottom of the outlet illustrated in the drawing is ordinarily sufiicient to accommodate the stratum which includes the principal values, and the lowermost spout is adjusted to divide the outfiowing stream at the upper limit of the value carrying stratum. If the upper strata contain no worth while amounts of values, a single spout 6 will be sufiicient and all of the portion of the stream received by the lower spout 6 may be disposed of in any convenient way. If the upper strata carry values worth recovering, additional spouts 6 are provided and adjusted to separately deliver the strata which carry the values. For example, if the condition of the valuable substance is such that it is segregated in one of the upper strata, as for example, in the case of fine flake gold which may be carried upwardly by the rising flow of the stream, the upper spouts are adjusted to separate the gold bearing stratum from the rest of the stream. Similar adjustment may of course be made for separating other strata carrying values of other kinds when desired. The location and extent of the various strata containing values worth recovering may be readily determined by analysis of the solid material segregated at various levels, and the spouts may then be adjusted accordingly.

In the classifying of dredger tailings and in similar types of service it has been found desirable to provide the hopper I1 with means for effecting an initial separation of gold, platinum, amalgam, mercury and similar heavy materials from the stream before it enters the conduit l.

For that purpose, the hopper I1 is widened toward its bottom and is provided with a baflie 26 for directing inflowing material toward the side opposite the outlet opening 22. A flow of water is introduced into the lower portion of the hopper, at a level slightly below the outlet 22, through a supply pipe 21. The flow of water is distributed by means of a plurality of branch arms 28, each of which is provided with a plurality of outlets 29.

The outlets 29 preferably comprise upwardly extending nipples delivering the water into hoods 3|, shaped to form a plurality of relatively narrow slot-like openings radially disposed around the nipples, and discharging downwardly toward the bottom of the hopper. Since the bottom of the hopper is normally closed, the Water so introduced causes a flow upwardly past the outlets 29. The upward current so produced is controlled by varying the amount of water supplied, so that only particles having a very high specific gravity will sink downwardly against the force of the upward current.

The outlets 29 are spaced to obtain a substantially uniform upward current above the hoods 3|; and to provide spaces through which heavy particles such as precious metals, amalgam, and mercury may settle to the bottom of the hopper. The bottom of the hopper I! is provided with a clean-out spigot 32 through which materials collected therein may be withdrawn.

This arrangement provides an effective means for separately collecting heavy particles of value which may be washed past the riifies of a sluice. At the same time, it facilitates the collecting of values and the cleaning up of the sluice. In this connection, it is only necessary to dump the riffles and wash the collected materials along the sluice and into the hopper. The precious metals, amalgam and mercury will sink to the bottom of the hopper against the force of the upward current of water therein; and may be removed through the spigot 32. Any values which may be carried through the hopper into the classifier conduit I are of course collected with other values segregated by the classifier.

The provision of a separate supply of water into the hopper is of course optional, and may be omitted if desired.

I claim:

1. In a classifier, a tubular conduit of rectangular cross-section having substantially uniform cross-sectional area at all points along its length and having a wide shallow inlet and a deep narrow outlet, selector spouts arranged at the outlet end of the conduit to receive various strata of a stream flowing from the conduit, and means for adjusting the inclination of the con-' duit.

2. In a classifier, a conduit having a wide shallow inlet and a deep narrow outlet, the cross sectional area of said conduit being substantially the same through the length of the conduit, a hop-per connected to the conduit, means for directing a stream of water and entrained solid matter into the top of the hopper for delivery to the conduit, and means in the lower portion of the hopper for introducing water into the stream within the bottom of the hopper in a substantially even upward trend for partially classifying the material prior to entry into the conduit.

CHARLES J. SCHIFFERLE.

Images