US1429480A

US1429480A - Ore classifier

Info

Publication number: US1429480A
Application number: US261191A
Authority: US
Inventors: Allen Charles
Original assignee: Individual
Current assignee: Individual
Priority date: 1918-11-05
Filing date: 1918-11-05
Publication date: 1922-09-19
Anticipated expiration: 1939-09-19

Description

C. ALLEN.

ORE CLASSIFIER.

APPLICATION FILED NOV-5,1918.

I IV I/E IV TOR Charles/ len PatentedSept. 19, 1922.

A TTORNEK Patented Sept. 19, 1 922.

UNHTED CHAR- LES ALLEN, OF EL P-ASO, TEXAS.

ORE CLASSIFIER.

Application filed Novemberfi, 1918. Serial No. 261,191;

To all whom it may concern:

7 Be it known that I, CHARLES ALLEN, a citizen of the United States, residin at El Paso, in the county of El Paso and tate of Texas, have invented new and useful 'Improvement in Ore Classifiers, of which the following is a specification.

This invention relates to ore milling, and

- pertains especiall vto an apparatus for classi- 10 fying the metalliferous particles coming from the mill, such apparatus being commonly termed an ore classifier. The func tion of a classifier is to divide the solid particles into two or more products, the particles composing the products difi'ering in size or weight. The classifier commonly includes a sorting column, down through which the solid particles fall against an upflow current to eifect classification, the solid particles falling through the column being separated from the pulp as it comes from the mill.

As the proportion of coarse particles to fine particles varies continually in a mill stream, constant attention would be required to vary the velocity of the rising current in the sortin column to correspond with the quantity of solid particles falling through it, provided the highest degree of separation was desired or possible, and provided there is no automatic means for controllin the velocity flow of the rising current. rdinarily, in mill work, the valve which controls the upflow, is altered only for every large variation in the amount of solids in the sorting column.

The present invention finds its embodiment in the form of a by-pass for auto-' matically regulating or adjusting the upcurrent flow to the falling metalliferous particles in the column, whereby to maintain a substantially uniform velocity of flow of the upcurrent regardless of the volume of occupancy of the column by solid particles,

within reasonable limits.

The accom anying drawing illustrates the invention. he inflowing pulp enters at 10 and is received into a funnel 11 of a sorting column 13 and is subjected to an effect of this rising current is to break up the pulp; the lighter particles beingcarried into the overflow launder 12 and the heavier particles (those which have sufiicient weight to fall against the rising current), fall through the sorting column 13 and into the receptacle 14, whence they are discharged through the spigot'15.

None of the feedstream water, that is, the water coming in from the launder 12, passes down into the sorting column 13; all that enters the sorting column. fro-m the feed stream is the heavier particles which have suflicient Weight to sink out of the feed stream and into the rising current in 13. The column 13 is called a sorting column because its function is to sort the lighter from the heavier rains. The rising current which is supplied to the sorting column, enters from any suitable source through a pipe '16, the velocity of which rising current is controlled by the valve 17.

From the foregoing, it is apparent that when the machine is in operation, the sorting column 13 is filled with the fresh water of the uprising current and the falling ore particles; the upflow being between these solid particles in the sorting column. In other words, the area through which the water may pass is controlled by and to the amount of, the falling particles present. Whenever it is so contracted, the velocity of the rising current is increased (in the absence of the by-pass 18), so that under such conditions the particles which would normally fall through the sorting column cannot enter it and are carried over into the launder 12. This is one-of the causes of poor work in an ordinary hydraulic classifier.

difiiculty of loss of values by accelerated up-current flow, I provide the by-pass 18 between the receptacle 14: and the top of the sorting column, the action of which by-pass is as follows? When no solid particles are present in the sorting column, the classifying water entering at 16 rises through 13 and 18 at the same rate and in proportion to their cross-sectional areas. When the sorting column is 100 To overcome this difliculty, that is, the

partially occupied with falling Solids, its

. area is contracted, as explained above; but instead of an accentuated upflow, that is, an

produces an automatic -balance of current flow in proportion to the falling particles so that the same results practically are accomplished at all times and without loss independent of the variations (of course, within usual working limits), of the amount of solids in the sorting column; thus producing the same result that might be produced through a constant regulation of the valve 17 if no by-pass were present.

The beneficial effects of this improved classifier are apparent when it is considered that with a sorting column not equipped with my automatic by-pass attachment, the velocity of the rising flow is increased 100% if the column is 50% occupied with solids; that if the sorting column is 75% occupied with solids, the velocity of the rising flow is increased 200%. The velocity. of the flow through the column is at all times dependent upon the density in the sorting column and the density of the sorting column is in turn dependent upon the occupancy of the column b solid articles in suspension or sinking t rough 1t.

While I haveshown the preferred form of nry invention as now known to me, it will be understood that various changes in the construction, combination and construction of parts may be made by those skilled in the art wlthout departing from the spirit of my invention as claimed.

The density of the contents of the sorting column increases proportionately to the occupancy of the sorting column only while the specific gravity of the material falling through, or in suspension in the sorting column remains constant. For instance, with a sorting column 10 inches long and the fluid water with a specific gravity of 1, when no solids are present the velocity of the rising flow is the same through both the column and the by-pass. The volumes are proportionate to their respective cross section areas. If when in operation under these conditions, material having a specific gravity of 3 be introduced into the column until the falling particles, or particles in suspension, occupy 50% of the volume of that part of the column between the upper and lower connecantennae tions to the by-pass, it will be occupied by flow through the by-pass, and, as long as the material causing the increased density in the column retains a specific gravity of 3, the weight of the contents of the column and the volume of the material occupying the column remain relatively the same. That applies to material of any given specific gravity, but, if the material of the specific gravity of 3 be replaced in the column by the same volume of material having a specific gravity of, say, 7, the mean specific ravity of the contents of the column is a. fience the velocity head, or pressure to the flow through the bypass, is twice what it was with an equal volume of material of the specific gravity of 3 occupying the column. The result is an increase of approximately 25% in the flow through the by-pass.

To cause a rising flow through the sorting column 13 water must be admitted to the receptacle 14 in excess of the discharging capacityof the spigot opening 15. The pipe 16 must be large enough to pass a suflicient volume of water but its cross-section area is dependent upon the velocity head to the flow The relative proportionate areas and lengths of the different parts of the device will vary with the conditions under which it is to operate and the character of the material to be classified.

When there are no solids present in the classifier the volume of water entering the receptacle in-excess of the discharging capacity of the opening 15 is the sole determining factor of the velocity of the rising flow through thesorting column 13 and the by-pass 18, while practically the sole determining factor of the velocity of the discharge through 15 is the vertical height of the fluid column over 15, which is equal to the distance from 15 to the overflow rim of the hopper. If this distance were four feet, there would be a velocity of issuance of 192 inches per second. 4

Assume that a three inch per second rising flow through the sorting column will per square inch of cross section area.

sorting columnis such that when filled with water only the weight of the column is 10 ounces per s uare inch of cross section area at its base. hen, when the density of the contents of the sorting column has increased to 1.5.the weight has increased to 15 ou (1)ces ne cubic inch of water at ordinary temperature weighs 0.57 64v ounces. Hence 5 ounces equal the weight of a column of water of one square inch cross section area and 8.67 inches (0.72 ft.) inheight. This additional velocity head is all effective on the flow through vthe by-pass; that is, the velocity of the flow through the by-pam from three inches to 81.7 inches per second. At the same time, the effective velocity head to the discharge through 15 has been increased from 4 feet to 4.72 feet and the velocity of issuance from 192 inches to 208.8 inches per second. Therefore the volume discharged through 15 due to an increase in the density of the contents, of the sorting column from 1 to 1.5 cannot exceed 16.8 cubic inches per second, per square inch of cross section area.

This is the theoretical maximum and under operating conditions it is always less.

In many cases when the devlce is classifying the volume of water discharged through 15 is less than when no solids are present, for the reason that the classified solid particles are discharged through 15 and by their presence diminish the area available for the outflow of water.

- ent isa by-pass whereby an increase in density of v the column by 1. In the classification of fine ores, fine coal and the like in a sorting column wherein the material to be treated flows downwardly against the action of a rising current of water, causing the lighter product to overflow the rim of the column and the heavier product to pass out through a discharge orifice at the bottom of the column that step which comprises the by-passin o a portion of the up-flowing stream from ottom to top of tlfi column whereby to maintain a substantially uniform velocity of flow of the up-current in the column re ardless of the volume of occupancy of the co umn by solid particles within usual working limits. 2. In the classification of fine ores, fine coal and the like, the method of efi'ecting an automatic regulationof the up-flow'of water in a sorting column of the type disclosed which consists in providing the column with the contents of the sorting column will act to increase the volume of water Joy-passed, for

the purpose of maintaining a substantially uniform velocity of flow 'of the up-current regardless of the volume of occupancy of solid particles, within usual. working limits.

3. In a classifier for fine ores, fine coal, and the like, the combination of a sorting column having an overflow rim and a bottom discharge orifice, and through which the material to be separated normally tends to flow in a downward direction, means for producing an upward current therein, and means for. establishing a second'path of current between the opposite endsof said column, whereby an increase in the density of the contents of the sortin column will act to increase the volume of water by-passed for the purpose of automatically regulating the upward current in the sorting column in accordance with the requirements of classification.

4. In a classifier for fine ores, fine coal and the like, a classifying column, a discharge spigot at the'lower end thereof, a pulp supply spout above said oolumn, -means for maintaining a continuous upwardly flowing stream of clear liquid through the column, and means whereby said liquid may be diverted in quantity proportionate to the resistance of 1ts passage through the column.

5. In a classifier for fine ores, fine coal and the" like, a vertical column having an enlarged funnel-shaped mouth into which the material to be classified may be delivered,-a receptacle inclosing the lower end of said column and being provided with a restricted discharge orifice, means for continuously the like, the combination of a sorting column, a funnel at the mouth of the column into which the pulp stream to be acted upon discharges, means for delivering water to the lower end of the sorting column to create an up-flow therein to efl'ect classification, a by-pass whereby a portion of thewater that would otherwise pass through the sorting column, may be shunted around the sorting column back into the funnel, whereby an increase in the density of the contents of the sorting column will act to increase the volume of water by-passed for the purpose of automatically regulating the upward current in the sorting column inaccordance with th requirements of classification.

7. In a classifier for fine ores, fine coal, and the like, a sorting column having a launder at the top, means for continuously feeding material to the column at the top thereof, a receptacle at the bottom of the column having a restricted discharge ori-- fice, means for admitting water tothe receptecle to eeuse em upward flew in the cellmy hand in the presence of two subscribing 11mm, and e kg-pass exgtegdinglfrem jgthe Ifiwltnesses. cetecletotetepe tecoumn orte pe t-pose of by-passing water in varying CHARLES ALLEN 5 quantities eccerding to verietions in the den- Witnesses:

sity of the contents of the column. I W. H. BUMPER.

lintestimeny whereof I have hereunte set EDMUND SHAW.