US2219730A - Classifier - Google Patents

Description

Oct. 29, 1940. c. E. WOOD 2,219,730

' CLASSIFIER Filed May 19, 1937 2 Sheets-Sheen l 31 NVENTOR 25 I BY v ATTORNEYQ) 2 Sheets-Sheet. 2

NEYS

c E. WOOD CLASSIFIER Filed May 19, 193'! W Fr Oct. 29, 1940.

Patented Oct. 29, 1940 UNITED STATES PATENT OFFICE CLASSIFIER, 7 Charles wood, Milwaukea wis. Application May 19. 1937, Serial No. 143,408

2 Claims.

This invention relates to improvementsv in classifiers. r

One of the primary objects of the present invention is to provide apparatus for achieving classification under relatively constant conditions and automatically discharging the oversize product with minimum liquid displacement and in very much reduced space.

More specifically, I propose to reduce the vertical height of conventional classification apparatus by confining the automatic discharge of solids to a hopper having very much less area. than that of the entire bowl, the weight of the hopper contents being utilized to control automatic discharge therefrom. By the same means I avoid bowl proper and thereby tend to maintain conditions for classification in the bowl more uniform than heretofore. Uniformity of operating'condigo tions is further promoted by an arrangement in which the rakes or raddles which are preferably employed to deliver the oversize solids tothe discharge hopper, are operated at substantially the same speed in which the mass of water and sus- 25 pended solids in the bowl are turning in a vortex produced in the delivery of the material thereto.

Other objects will appear from thefollowing disclosure of the invention.

In the drawings:

30 Figure 1 is a vertical sectional view showing apparatus for the present invention.

Figure 2 is a fragmentary detail view of'the discharge hopper in side elevation from a viewpoint at right angles to that of Figure 1.

35 Figure 3 is a plan view of the classification bowl andassociated parts, the super-structure being removed.

Figure 4 is a fragmentary detail view on an enlarged scale showing in section similar to Fig.- 1

40 the lconnection of the discharge hopper to the Figure 5 is a fragmentary detail partially in plan and partially in section showing the attachment of the raddle arms to their actuating shaft.

45 Like parts are identified by the same reference characters throughout the several views.

The classification bowl 6,is of generally conventional form carried on any suitable supports in a horizontal position with the upper margins 50 of its wall 1 horizontal for uniform discharge of liquid and undersize product throughout its periphery. The wall I of the classification bowl is preferably surrounded by a launder 8 with a discharge spout at 9 for delivery of the water and 55 undersize product which overflows the margins 1 substantial losses of the liquid contents of the of the bowl. The supports shown in the drawings are purely for purpose of illustration.

The classification bowl 6 is centrally apertured and provided with a downwardly extending sleeve v v at In through which oversize solids may be dis- I charged from the bowl. The sleeve projects into a hopper l5 carried by a sub-frame l6 and links l1 froma pair of scale beams l8. This arrangement provides for controlled vertical movement of the hopper with respect to the bowl. The an- 10 nular diaphragm 20 marginally clamped to the bowl 6 about the opening therein and to the upper margin of the hopper, seals the hopper while accommodating this vertical movement with subframe [6 upon the scale beam.

The weight of the hopper and its normal content of oversize solids is counterbalanced by the weight carriers 2| adjustable on the scale beams I8 and respectively provided with the usual scale weights at 22. The scale beams preferably overlap and are loosely connected by a bolt at 23 which accommodates their necessary movement and at the same time serves as a fulcrum upon which link 24 is suspended for the actuation of thevalve lever 25. This lever is pivoted in a 26 knife edge'26 engaging a bracket 21 carried by' the hopper. The free end of the lever beyond its fulcrum supports a pin 28 upon which a valve 30 of inverted conical form is centered to releasably plug the valve port provided in the closure plate 30 3| at the bottom of the hopper.

The arrangement is such that when a predeter mined weight of oversize solids accumulates in thehopper, the increased weight imposed on the sub-frame It will overbalance the adjustable a5 weights on the scale beams to tilt the scale beams in a direction tending to raise the link 24 and the outer end of lever 25. Thus, while the hopper moves downwardly, the link 24 is moving upwardly and the valve operating lever 25 will thereby be caused to pivot sharply in a valve opening direction. The opening of the valve'will allow the overweight solids to be discharged with only such water as lies between the particles of sand or other solids, and as soon as a sufilcient quantity of solids has been discharged to affect the weight of the hopper. the parts will movein directions reverse to those just described, with the result that the valve will again seat upon plate 3 I. ables it to center itself in the opening despite any displacement Which may be occasioned during or because of the discharge of solids thereover.

The water or other liquid bearing solidsto be classified is supplied through a flume 33 tangen- 55 The pivotal mounting of the valve ential to a volute delivery chamber 34 having an opening 35 in its bottom through which the whirling material is discharged into a. partially submerged pan 36, the sides of which are only slightly above the level of liquid in bowl 6 as determined by the height of wall 1. This pan has radial baffles 31 supporting it from a casing sleeve 38 which is rotatably carried by suitable bearings (not shown), from a vertical shaft 39, with respect to which the pan is free to turn. The pan is rotated by engagement of its bafiles 31 by the whirling mass of liquid and water borne solids delivered to the pan from the volute delivery chamber 34. v

The pan also has an opening in its bottomat 48, this opening being submerged. An apertured baffle disk 4| on shaft 39 is positioned immediately below the opening 40 to dissipate the incoming material uniformly in all directions.

The incoming material reaches the classifier bowl while still in rotation, and the distributing bafile system is intentionally so designed that it does not materially impede the rotative, movement of the liquid. Thus a broad slowly rotating vortex is established throughout the classifier bowl through the use of the energy of the incoming liquid. The movement of this vortex is, however, so slow that it does not in any measure impair the settling out of the oversize product to the bottom of the classifier bowl.

It is desirable that this deposit in the classifier bowl be kept at substantially a constant level in order that the flow of liquid thereover to the margin of the bowl may be as nearly uniform as possible. At the same time it is necessary to move the deposited oversize product to the discharge hopper 55 with a minimum of disturbance of the liquid.

To accomplish these results I drive shaft 39 from motor 43 through suitable reducing gearing at 44, and I mount on the shaft a set of radial supporting arms 45 and helically disposed raddles 46 which turn with the shaft at substantially the same rate at which the vortex rotates in the classifier bowl. Since the raddles are moving with the water, substantially no eddy currents will be formed behind any of the raddle blades 56. At the same time each of the raddles has a helical pitch such that the solid oversize particles encountered by the radclle blade at the bottom of the classifier bowl will be progressively moved for a distance equal to the pitch and extent of the blade toward the sleeve Hi which affords communication with the discharge hopper l5. At their inner ends the arms 45 may conveniently be mounted on the plate 48 supported by a collar 49 on shaft 38. The arms preferably have an upward inclination of about ten degrees and at points at or near their outer ends they are supported by tie rods 50 which connect them with another collar 5| higher up on the shaft. The arms may also be braced from each other by tie rods 52.

Any suitable structure may be employed for the support of the parts designated. That shown in the drawings is purely illustrative.

The invention from the standpoint of method consists, first, in employing the kinetic energy of the delivered material to establish a vortex in the classifier bowl, the oversize product being allowed to settle out and come to rest in the bottom of the bowl while the vortex movement of the liquid in the bowl continues. Secondly, by reason of such movement, the relatively non-rotating solids are moved centrally along the bottom of the lllinto the discharge hopper which, being small in diameter as compared with the bowl, can be I guided more readily for movement on the scale mechanism and also will require but little space.

' Since a certain angle or pitch of hopper wall must be used, the: depth or vertical dimension of the hopper can be kept to a minimum by reducing its diameter to a minimum.

'Theopening movement of the valve is accelerated as compared with the downward yielding of the hopper on the scalelbalance. Consequently the valve moves a much greater distance than the hopper, opening or closing rapidly. In operation the valve will assumea position open approximately enough to'qdis'charge the tonnage being delivered. Its balanced condition will result in a slight oscillation but the discharge will be generally constant' and equal to the tonnage of oversize material in the feed.

It will be observed thatthe space between the sleeve 10 and the" hopper constitutes an air crap. This prevents either the liquid or the separated solids from rising appreciably against the air pressure in the trap and, as a result, the diaphragm is protected from abrasion. Even if. a slight leak occurs past the diaphragm, there will be little, if any,sand coming. in contact with the diaphragm.

I claim:

1. A classifier comprising the combination with a generally circular bowl centrally apertured, of means associated with the apertured central por tion of the bowl for weighing and discharging solids therefrom, independently of the accumulations of solids in the-bowl proper, a rotatable rake system including raddle means helically pitched for the delivery of solids progressively to ward the bowl outlet, and means for maintaining the liquid in the bowl in rotation in a vortex having substantially the same direction and rate of movement as said rake system, said last mentioned means comprising a delivery flume opening centrally into said bowl and having a centrally apertured volute portion with which said flume communicates tangentially about the level of liquids in the bowl, and means partially immersed in the liquid of the bowl for receiving the whirling mass from'the flume, and bafile means for distributing such mass toward the periphery of the bowl without preventing its continued vortex rotation.

2. In alclassifier, the combination with a bowl of generally circular form having a central outlet, of a weighing discharge hopper having an an nular diaphragm connecting it with said bowl about said outlet, a valve in said hopper, weighing mechanism supporting said hopper for yielding movement respectingthe bowl upon the ac cumulation of a predetermined weight of material in the hopper, a discharge valve in said hopper provided with connections for actuating it in accordance with hopper movement upon said weighing mechanism, a driving shaft disposed substantially centrally in the bowl above the outlet thereof, and a rake system including radial arms and helical raddle means carried thereby for rotation with said shaft and within the bowl, said raddle means being' adapted to deliver pre cipitated solids toward said outlet, a flume having a volute delivery portion and a central discharge eye above the level of liquids in the bowl, a pan partially submerged in the bowl and positioned to receive material from said eye, said pan having a central outlet below the level of the bowl and a baflie positioned between said pan outlet and the outlet of the bowl for distribution of material throughout said bowl without interfering with its rotation, the communication of said fiume with said volute delivery portion being tangential in a direction tending to establish the rotation in the bowl of material admitted thereto at a rate and in the direction of rotation of said rake system, whereby classification in said bowl will be continuous without interruption by the movement of said rake system or the discharge of

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