US2365734A - Apparatus for separating solids in suspension medium - Google Patents

Description

Dec. 26, 1944. TRQMP 2,365,734

APPARATUS FOR SEPARATING SOLIDS IN SUSPENSION MEDIUM Filed May 14, 1940 2 Sheets-Sheet 1 mans F. TRUMP K. F. TROMP 2,365,734

' APPARATUS FOR- SEPARATING SOLIDS IN SUSPENSION MEDIUM Dec. 26, 1944.

Filed May 14, 1940- v 2 Sheets-Sheet 2 mvsm'oa KLRHS F. TRUMP aw faadlbni, 361.42 n'rranneYs Patented Dec. 26, 1944 APPARATUS FOR SEPARATING SOLIDS IN SUSPENSION MEDIUM Klaas F. Tromp, Kerkrade, Limburg, Netherlands; vested in the Alien Property Custodian Application May 14, 1940, Serial No. 335,078. In Great Britain June 30, 1939 4 Claims.

This invention relates to an improvement in the apparatus disclosed by my prior United States Patent 2,139,047, i. e. in apparatus for separating solid materials having different specific gravities by means of a suspension of sand in water. This apparatus comprises a tank containing a body of a suspension of sand in water having a downwardly increasing density, said tank being further provided, in addition to means for creating substantially horizontal currents in the suspension at different distances above the bottom, with means for removing suspension from different levels in the tank, means for removing the floating products; and one or more means for removing products transported by the currents towards the side wall at an intermediate level in the tank.

More especially my invention relates to the aforesaid means. for removing products. transported by the currents towards the side wall at an intermediate level in the tank. In accordance with my aforesaid prior patent, these means comprise one or more drag conveyors movable across side wall openings, through which suspension is adapted-to be discharged from difierent levels in the tank. In practice it has been found that this construction is not entirely satisfactory, owing;

inter alia, to the fact that a movable drag conveyor disturbs the parallel flow,,of the suspension and sets up eddies therein, whereby the suspended products are difficult to be caught. Moreover, the separation of these products from the suspension requires the use of a drag conveyor composed of perforated plate-links, or the provision of strainers in the discharge openings, and this has the inconvenience that said perforations or strainers are liable to be obstructed, whereby the horizontal flow of the suspension is braked.

This braking effect will increase as the amount of middlings increases, although just under these circumstances it is essential for the horizontal flow to b relatively strong in order that excessive avoided.

bath, and by the provision, beyond the submerged portion of the mechanical means for removing floating products, of a weir for discharging-substantially the whole amount of fluid flowing along substantially horizontal paths through the tank, together with the middlings suspended therein. It will be understood that with this construction the middlings will be discharged by hydraulic.

means, i. e. by an upwardly directed current of fluid in the vicinity of the weir.

The hydraulic discharge of the middlings transported towards the side wall of the tank main portion of the tank, the end portion of the The object of my present invention is to do away with the use of strainers, sieves or the like, so as to ensure an unimpeded transport ofthe middlings through the bath and thusto better adapt the apparatus to the separation of relatively fine materials, i. e.of materials that are very liable to clog the meshes of sieves or the like.

With this and other objects in view, my inventlon consistsin the dispension with of the metank may taper in the direction of flow. Alternately, or additionally, part of. the suspension discharged by the weir may be returned directly to said end portion, instead of to the suspension inlet openings of the tank as described in our prior specification.

Other. features of my invention will appear from the following description and beset forth in the appended claims. a

The annexed drawing shows, by way of example, two embodiments of the invention.

Fig. 1 is a vertical longitudinal section of the first embodiment, and

Fig. 1a is a top plan view thereof with the drag conveyor for the floating products broken away.

Figs. 2 and 2a are corresponding views of the second embodiment.

In Figs. 1 and 1a, the tank 3 has tapering front and rear walls, and vertical left and right hand side walls 4 and 5, respectively. Mounted in the lower portion of the tank is a horizontal drag conveyor 6 driven in clockwise direction and having its delivery end located vertically above an inclined chute I. A second drag conveyor 8, driven in antirclockwise direction, is mounted with a portion of its lower part parallel with the surface 9 of the body of suspension within the tank 3, a further portion of said part being parallel with an inclined'dewatering screen Ba, the

lower end of which extends downwardly to say chanical means for emoving middlings from the 4-6" below the level 9. The delivery end of conveyor 8 is .located vertically above 'anJnclined chute 10 connected to said stream. 7

.The left hand side wall 4 is provided with tvlvolil/ertically spaced suspension inletopenings I a.

As distinguished from the apparatus disclosed by my prior Patent 2,139,047, the right hand side wall of tank 3 is not provided with vertically spaced suspension outlet openings, and neither is tiere provided a drag conveyor for removing from the bath the middlings transported, by the suspension supplied through openings H, Ha, from left to right towards said side wall intermediate the surface 9 of the bath and the drag conveyor 6. Instead, the right hand side portion l2 of the tank located above the conveyor 6 tapers in the direction of flow of the suspension as indicated by arrows in Fig. 1, and merges into a relatively narrow, parallel-walled end portion l3, whose right hand side bottom corner is suitably rounded oiT as shown. The top edge of wall 5 is located substantially at, or somewhat below the level of the lower edge of dewatering screen 8a and forms a weir 5a.

Secured to the outer face of wall 5 is a dewatering screen l4, and mounted below said screen is a boot IS. The lower end of boot i5 is connected, through a conduit "5, with the suction side of a, pump If, the delivery side of which communicates, through a conduit l8, with a thickener IS. The lower end of the thickener is connected with a distributing pipe 20, and its overflow pipe 2| discharges into a hopper 22, the lower end of which is connected to a distributing pipe 23. Said distributing pipes are adapted to discharge into conduits communicating with the inlet openings il a and Ii, respectively.

The pipe I8 has a control valve 33 and a pair of pipes 35a and 35b connected thereto, each in turn having an individual control valve 34, said pipes communicating through apertures 36a and 36b with a chamber l3 of Figs. 1 and 1a. Thus. part of the suspension from boot i 5 carried up into pipe l8 may be returned through pipes 35a and 35b to the lower portions of the uptake or compartment 13 so as to further increase the vertical velocity of flow in the same.

The modus operandi of the described apparatus, as far as the gravimetric separation of the material treated therein is concerned, is not essentially different from that of the apparatus disclosed by my aforesaid prior patent. That is to say, assuming run-of-mine coal to be charged into the tank as at A, and'the drag conveyors 6 and 8 to be suitably driven, the pure coal will float, be carried by the lower part of conveyor 8 towards the dewatering screen 811, and raked over this screen so as to be lifted out of the bath, whereupon it slides down over the chute I 0 to be further conveyed by means not shown.

The slate sinks to the bottom, from which it is removed by'the conveyer 6.

The middlings, for instance bony coal, will sink below the surface 9 of the bath and remain sus pended at a greater or smaller depth below the level of the submerged left hand side portion of screen 8a, since the suspension in the tank has a density increasing from top to bottom owing to the slow settling of the sand." The substantially horizontal currents created by the suspension fed into the tank through the inlet openings ll carry the suspended middlings towards the right, i. e. towards the portion I3, in which the fluid is compelled to flow upwards. The middlings are forced to follow this movement so as to be discharged, together with the suspension, by the weir 6a, providedthat the suspension in said portionhas the required vertical velocity. As will be understood; the taper of the right hand side portion i2 of tank 3 has the effect of increasing More the velocity of the suspension flowing towards the portion i3 so as to ensure the desired hydraulic discharge of the middlings in upward direction through said portion, which thus actually functions as an uptake.

The middlings thus discharged are further conveyed by means not shown, and the suspension is collected in boot l5, whence it is fed, by pump H, to the thickener iii. In this thickener, the sand" is allowed to settle to a certain extent, so that a relatively light suspension overflows into hopper 22 to be supplied to the tank through the distributing pipe 23 and the upper feed opening ii, and a relatively heavy suspension is discharged into the distributing pipe 20, whence at least part thereof returns to the tank through the lower feed opening I la.

Figs. 2 and 2a show an apparatus, which, as far as the parts designated by the references 3 to inclusive l2 are concerned, does not essentially differ from the one illustrated in Figs. 1 and la. As to the narrow, parallel-walled right hand side end portion l3 of the tank, however, this has mounted therein two vertical, transverse partltions 24 and 25 suitably spaced in the direction of flow so as to divide portion I3 into three compartments 26, 21, 28. The lower edges of these partitions are located at different levels intermediate the level of the lower, submerged edge of screen 8a, and the conveyor 6. The partition 25 nearest to the side wall 5 extends to a greater depth than partition 24. Said partitions are provided, along their lower edges, with more or less horizontal extensions 24a, 25a, respectively, pointing to the left.

The rear wall of the portion l3 of the tank is of reduced height so as to form a stepped weir 29 for the discharge of suspension and middlings from compartments 26, 21 and 28, respectively into chutes 30, 3i and 32, respectively. As will be observed,'the stepped weir extends on either side of partition 25 as also of partition 24.

As diagrammatically shown, partition 25 is adapted for vertical adjustment. Partition 24 may be mounted in a similar manner.

Obviously, in the apparatus just described suspensions and middlings of increasing specific gravities will be hydraulically discharged, through compartments 2B, 21 and 28, respectively, by the weir 29, which delivers them to the chutes 80, .3] and 32, respectively. The suspensions are drained oil and the middlings washed by means not shown. Said suspensions as well as the suspensions recuperated from the washing water may be collected and returned to the inlet openings ll, Ila, lib, lie of the tank in the manner dethe lower portions of said compartments so as to still further increase the vertical velocity of flow therein. This has the advantage that with a predetermined low velocity of the substantially horizontal currents created in the main part of the tank any desired vertical velocity of flow in the uptakes 26, 21 and 28 can be obtained.

Figs. 2 and 2a show an apparatus with three uptakes 26, 21, 28, but it will be understood that if necessary the middlings may still further be graded by providing the right hand side portions I: of the tank with three or more suitably spacedv partitions, the lower edges of which extend downwardly to depths increasing in the direction of flow of the suspension. In other cases, only one partition will suflice.

What I-claim is: 1. Apparatus for separating solid materials of different specific gravities by means of a liquid suspension, comprising a tank having side walls and end walls, an outlet trough leading from the tank at one of said side walls, thereby maintaining the liquid level substantially constant in the tank, the upper portion of the tank end walls converging inwardly toward the other side wall to thereby diminish the cross sectional area of the tank, a transverse partition connecting the proximate faces of said converging end walls at a point disposed in spaced relation to said other side wall, and separating the tank into two compartments, said partition having an opening therein below the liquid level, an inlet conduit in the other side wall of said tank substantially at the level of said opening, said conduit extending substantially from one end wall to the other, means for introducing unseparated materials into said liquid through said inlet whereby said liquid and the materials suspended at the level of the opening will flow horizontally through said opening into the adjacent compartment and into said outlet trough, conveyor means disposed above said opening for removing the suspended materials from said liquid between the liquid level and the top edge of the opening, and a second conveyor means disposed below said opening for removing the solids in the lower portion of the tank from said liquid, whereby the horizontal flow of the liquid and suspended material disposed at the level of said opening will be unimpeded and the velocity flow from one of said compartments to the other at the level of said opening will increase as the cross sectional area of the tank decreases.

2. Apparatus Ior separating solid materials of dlflerent specific gravities by means or liquid suspension, comprising a tank having the end walls thereof converging inwardly and terminating in a side wall, the upper edge of said side wall servmg as a weir over which the liquid flows from the tank, a transverse partition disposed in spaced relation to the side wall and connecting the proximate faces of said converging end walls, the lower edge of said partition projecting a uniform depth below the liquid level, a second transverse partition disposed below and in spaced relation to said first partition thereby forming an opening, means for delivering unseparated materials to said tank at a level substantially opposite said opening to cause a horizontal flow of the liquid and suspended materials at the opening level from said delivery means, through said opening, and then upwardly to said weir, means located above the lower edge of said first partition for removing the suspended materials disposed above said lower edge, means located below the upper edge of said second partition for removing the suspended materials disposed below said upper edge, whereby the horizontal fiow of the liquid and suspended materials at the level of said space between saidlpartitions will be unimpeded and the velocity flow at the last-named level will increase as the cross sectional area of the tank decreases.

3. Apparatus according to claim 1 having means including a liquid current for conducting a portion of the material being discharged by said trough to the bottom f the compartment adjacent said other side wall, whereby the upwardly directed liquid velocity in said latter compartment will be increased.

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