US1720810A - Deslimer and classifier - Google Patents

Description

y 6, 1929. J. R. WRIGHT 1.720.810

DESLIMER AND CLASSIFIER Filed fi 1927 2 Sheets-Sheet 1 July 16, 1929. J. R. WRIGHT DESLIHER AND CLASSIFIER File Aug- 192'! 2 snaps-sheet 2 dirk/lava fl/PzW/r Patented July 16, 1929.

PATENT OFFICE.

JAMES RAYMOND WRIGHT, OF DENVER, COLORADO.

DESLIMER AND CLASSIFIEB.

Application filed August 5,

* removing the fines and slimes from the pulp feed to the gravity concentrating apparatug of the mill so that the treatment of the coarser material by gravity will not be in terfered with and so that the slimes can be collected for chemical, flotation or other treatment. The invention is also designed for use on the tailings from the gravity concentrating apparatus so that the coarser material which has been treated can be discharged as valueless and the fines, which the gravity machines could not treat properly, can be returned for proper treatment with the slimes from the mill feed.

The principal object of the invention is to provide a continuously operating classifier or deslimer which will not interfere with the continuous feedflow required for proper concentration, which will be highly e-fiicient in operation; which will require but a minimum of water; and which will not become choked or clogged.

Another object of the invention is to provide a machine which can be used to prevent the slimes from being'lost with the gravity tailings and which will at the same time dewater and save a largetpercentage of the water usually lost with thetailings of a mill. This last object, of course, becomes valuable in proportion to the value of the water at the mill site.

A further object is to provide a machine through which the coarser material will pass in a continuous flow and in which the tines will be collected and stored to be discharged at intervals or continuously as desired.

Other objects and advantages reside in the detail ccmstruction of the invention, which 1927. Serial No. 210,786.

ciency. These will become more apparent from the following description.

In the following detailed description of the invention, reference is had to the accompanying drawings which form a part hereof. Like numerals refer to like parts in all views of the drawings and. throughout the description.

In the drawings:

Fig. 1 is a longitudinal vertical section through one form of my improved machine. This view is taken on the line 11, Fig. 2.

Fig. 2 is an elevation of the discharge end of the machine of Fig. 1.

Fig. 3 is a fragmentary plan view of a typical one of the feed boxes employed on the machine.

Fig. 4 is a side elevation partly broken away of an alternate form of the machine to be later described.

Fig. 5 is a cross section,-taken on the line 55, Fig. 4, throughthealternateform of the machine.

Fig. 6 is'a detail crosssection taken on the line 6-6, Fig.1, illustrating in diagram the classifying action of the machine.

The invention comprises all of the features, parts and details of-construction and combinations thereof hereinafter described which are necessary or useful in accomplishing the object of the invention.

In all forms of the invention a relatively long v.V-shaped tanklO is employed, in which a suitable roll supporting frame 11 is carried, extending throughout the. length of the tank, for the support of a relatively wide endless belt 16. A relatively short idler belt 15 is carried between each pair of idler belt rollers 13. The idler belts, being relatively short, can be kept sufiiciently tight so that any sag therein will not be apreoiable. These idlernbelts maintain. an almost continuous plane surface for the support of the belt 16 andprevent any sag lnits upper reach or working surface. .The return reach of the belt '16 is supported on return rollers 14, from whence it'turns overa tail roller l2 to its upper reach on the idler belts.

An angularly placed pressure belt 17, carried on ressure rollers 18, is provided, against wiiich, thenpper reach of the belt 16 bears .asit passes titan-.11 ward an 1e out of the solution in 1 the .tanli .10 an over an elevating roller. v19. to: a drivingroller beyond the extremity of the tank. The lower reach of the belt 16 returns from the driving roller 20 over the end of the tank on a similar elevating roller 21 to a head roller 22 which aligns it with the return rollers 14.

Pulp is fed to the machine by one or more launders 23 in either a dry or fluid suspended condition. The pulp is received in feed boxes 24, one box being placed below each of the launder-s 23.

The feed boxes 24 are relatively long, narrow boxes provided with perforated o1 screened bottoms 25. They are arranged along the medial line of the belt 16 with their greatest length parallel thereto and their bottoms parallel to and spaced above the belt. Baffie boards 26 extend entirely across the tank 10 at each end of each of the feed boxes 24, in fact they may form, if desired, the ends of the boxes as illustrated. These baffle boards 20 may extend entirely across the belt 16 and are suspended just above the beltsurface. The number of feed boxes is optional depending upon the length of the tank 10 andthe capacity desired.

'lVhen employing the machine to prepare the pulp for concentrating apparatus, the pulp is fed to the feed boxes directly from the crushers, preferably mixed with water.

It enters the solution in a quiescent zone enclosed in the feed box and slowly filters through the perforated bottom 25, causing a mild current to flow from the center line of the belt 16 outwardly toward both edges thereof, as shown in Fig. 6. This current is forced to flow in a lateral direction by being confined between the laterally extending baflle boards 26. The coarse, heavy particles fall directly to the belt and accumulate along its mid-portion. The fines and slimes stay in suspension longer and are carried by the current over the edges of the belt into the tank 10.

There will be a classification of the pulp upon the belt ranging from the coarsest material. along the center line to fine material at its edges. The amount of fine material retained depends upon the amount of water admitted with the pulp, which of course, effects the speed of the classifying current, and also on the speed at which the belt is traveling. 7

Should it be found that too large a percentage of fines remains on the belt, the

, sible.

tance of conveyance.

that the first deposited pulp will be subjected to further classifying current under the subsequent boxes, should more than one box be used. The subsequent currents, however, are not of sufiicient strength to cause any loss in the coarser particles deposited. After passing from under the lastfeed box, the belt turns upwardly to emerge from the solution. At this point, the pressure belt contacts with the upper belt surface and prevents the surface tension from drawing the deposited material back into the solution.

The majority of the pulp falls from the belt 16 as it passes around the driving roll 20 into a receiving hopper 28. Any residual pulp may be washed from the belt by means of a water spray 29, or may be brushed therefrom by means of a suitable brush, as is common in vanner practice. The pulp is conveyed from the receiving hopper through a launder 27 to the concentrating apparatus. The belt may be driven by any suitable drive mechanism, such as a belt pulley 30 and drive belt 31. The fines and slimes settle to the V-shaped bottom of the tank,

and are conveyed along the bottom by means of a screw conveyor 32 to a receiving box 33. It is preferred to make the conveyor right and left hand so that it will be double acting, as illustrated, so as to shorten the dis- The fines soon pack and form a bottom or lining around the conveyor which prevents wear on the tank.

The slimes may be discharged at suitable intervals, or continuously, through a gate valve The screw conveyor 32 may be rotated in any desired manner, such as by a sprocket 35 and sprocket chain 36. The frame 11 extends over the extremity of the tank 10 so as to support all of the rollers both on the interior and exterior of the tank. It may be attached to the tank by means of suitable flanges, as shown at 3L.

In the alternate form of the invention, illustrated in Figs. 4 and 5, a receiving tank 38 is attached to the discharge end of the tank 10. The receiving tank is open to the tank 10, so as to receive solution therefrom and maintain a solution level equal to that in the tank 10. This receiving tank may be supported on an extension 10 of the frame 11 and is so arranged that a drive roller 41 similar to the drive roller 20, previously described, will cause the belt 16 to partially submerge in the Water of the receiving tank 38. This submergence washes the pulp from the belt, allowing it to settle to the bottom of the receiving tank 38.

The bottom of the receiving tank is inclined and contains a screw conveyor 39 which elevates the deposited pulp above the solution level in the tank and allows the water to drain from the pulp back into the tank. This form of the invention is especially valuable where it is desired to save water since the same water that is used in the tank 10 is also used to wash the pulp from the belt at the discharge, no pump being required. The main belt constantly adds water, to the receiving tank 38 so that there is a slight current into the tank 10 through the opening 37. This current carries back any slimes which may have been accidentally carried over by the belt.

This form has a special application in dewatering and desliming the tailings discharged from a gravity separation machine, such as a concentrating table. These gravity machines operate efficiently on the coarser particles so that the tailings from these machines carry barren, coarse gangue and metal bearing fines. By discharging the tailings into the tank 10, these coarse, barren particles can be separated from the value carrying lines and slimes. The coarse tailings are carried up the inclined bottom of the receiving tank 38 by the screw 39 and discharged into the tailings dump. These tailings carry very little water since they are drained on this inclined bottom so that loss of water in the tailiugs is reduced to a. minimum. The slimes which have not received their proper treatment are then reconveyed to the mill system from the tank 10 and are treated by processes, such as flotation, etc., suitable to their fineness.

The feed boxes 24 may be supported from the battle boards 26, which can be extended from side to side of the tank 10, if desired as illustrated in Figs. 2 and 6. The tank 10 may be supported on cross beams 42 from which project angle braces 43 throughout the length of the tank.

\Vhile a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what I claim and desire to secure by Letters Patent is 1. In a classifying device having a belt adapted to raise settled material from a liquid in a tank, means for preventing the surface tension of said liquid from drawing said material from said belt as it emerges comprising a second belt adapted to lie against and contact with the carrying surface of said first belt along the portion of the latter which is emerging from the liquid.

2. A device for separating the fines from ore pulp comprising: a V-shaped liquid containing tank; a belt adapted to move horizontally in said tank below said liquid; means for causing said belt to rise above said liquid a portion of its travel; a second belt adapted to lie against and contact with that portion of the first belt rising above said liquid so as to prevent the surface tension of said liquid from drawing material from said belt as it emerges; means for removing material from said first belt after it leaves said second belt; and means for placing material in said liquid along the center line of said first belt.

A device for separating the fines from ore pulp comprising: a V-shaped liquid containing tank; a belt adapted to move horizontally in said tank below said liquid; means for causing said belt to rise above said liquid a portion of its travel; a second belt adapted to lie against and contact with that portion of the first belt rising above said liquid so as to prevent the surface tension of said liquid from drawing material from said belt as it emerges; means for removing material from said first belt after it leaves said second belt; and means for placing material in said liquid along the center line of said first belt; said second belt initially contacting with the material on said first belt below the surface of said liquid.

In testimony whereof, I affix my signature.

J. RAYMOND V RIGHT.

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