US2752040A - Sink-float separatory apparatus - Google Patents

Description

June 26, 1956 R. SCHREIBER ETAL SINK-FLOAT SEPARATORY APPARATUS 3 Sheets-SheenI 1 Filed Aug. 17. 195s INVENTORS RUDULF 5CH/FUEL? June 26, 1956 R. SCHRElBER ETAL. 2,752,040

SINK-FLOAT SEPARATORY APPARATUS 5 Sheets-Sheet 2 GER/#IRT W SCI/UE TZ June 26, 1956 R. SCHREIBER ET A1. 2,752,040

SINK-FLOAT SEPARATORY APPARATUS 17. 1953 3 Sheets-Sheet 3 Filed Aug.

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INVENTORS RUDOLF SCHE/EER GEPHT W. SCHUETZ SNK-FLOAT SEPARATORY APPARATUS Rudolf Schreiber, Manhasset, and Gerhart W. Schuetz, New York, N. Y., assignors to The Ore & Chemical Corporation, New York, N. Y., a corporation of New York Application August 17, 1953, Serial No. 374,686

7 Claims. (Cl. 209-173) The invention relates to apparatus for gravity separation of materials, as in coal cleaning, ore beneticiation, classification of solids, and for other uses.

Summary Apparatus of the kind to which our invention relates operates on the general principle of gravity separation in liquid media. When the liquid medium consists of water and iinely ground materials such as, for example, finely ground magnetite, ferrosilicon or galeria mixed to a specic gravity which oats one component of the feed material and permits another component to sink, the process performed with theuse of the sink-oat apparatus is generally referred to as dense media or heavy media separation.

Gravity separation has generally been performed herctofore with apparatus Classifiable under three type headings, viz cone-type separators, drum-type separators and screw-type classifiers. With the last-named apparatus, the usual objective is the gravity separation of coarse particles from fine in a water suspension, and the apparatus is called a classifier because it makes a classification of solids according to size through the difference in settling rate of diiferent size particles in suspension. For many purposes the cone-type separator has long been preferred over the others, but it has certain recognized disadvantages such as the limitation it imposes on the maximum size of the component which sinks in the medium (commonly referred to as the sink),. This limitation on size of the sink material which can be handled arises by reason of the fact that when the sink fragments become too large their removal from the bottom of the cone is difficult. Generally this removal is effected by an air lift which comprises a pipe through which compressed air iiows in an upward direction, lifting the sink from the apex at the bottom of the cone up to a discharge point at or beyond the rim of the cone. Sometimes a mechanical bucket conveyor lift is used in place of an air lift in an effort to overcome the limitation on sink fragment size, but this introduces complications of design, construction, cleaning and maintenance.

Drum separators overcome the limitation on size of sink fragments, but introduce other problems. In general, this type of separatory vessel comprises a cylindrical drum which rotates on a horizontal axis. A series of vanes around the inside of the rotating drum lift the sink to a discharge point above a chute which extends in a generally axial direction from within the drum to a point beyond one end of the drum. This apparatus requires the use of heavy rotating parts and gives rise to diiiicult problems of cleaning and maintenance. Also the vanes, which continually rotate through the pool area, create eddy currents which interfere with the sinking and oating separatory action. Furthermore, the fact that with this type of apparatus both the sink and the oat must be removed from the end of the drum, i. e. axially, creates design problems and limits the pool area.

2,752,040 Patented June 26, 1956 Screw-type classifiers have only limited application to sink-float processes, being designed primarily for other purposes. These classifiers are large, taking up a great amount of oor space, and are expensive to build and maintain.

lt is an object of our invention to provide apparatus for sink-float separation, or classification of solids, which overcomes or minimizes these and other difficulties inherent in separatory apparatus of the several types described above or in other forms of apparatus heretofore known. According to our invention there is provided a vessel which is of generally arcuate form in vertical section, a rake movable back and forth in a generally arcuate path within the vessel to move sunken material from the bottom of the vessel to discharge outlets at the respective ends of the arcuate path, and a discharge weir for iioating material. Arranged within the vessel is a bale encircling a pool for floating material, and the rake is mounted on an oscillatory supporting arm which extends between the baille and the sides of the vessel. The supporting arm extends for some distance in the general direction of the arcuate path of movement of the rake and thence radially with respect to such path to a pivotal mounting above the vessel. A troughk extends frorn the discharge Weir to receive material suspended in the liquid medium, which suspended material may comprise either iloating material, or 'due particles which have not had time to settle out, or both. When the rake is at one end of its arcuate path of movement, this trough extends above the supporting arm of the rake. Other features of our invention will appear as the description proceeds. Y

Description With reference to the accompanying drawings we shall now set forth the best mode contemplated by us for carrying out our invention.

Fig. l is a view of our preferred form of apparatus, showing the separatory vessel and associated structure in vertical section and the operating mechanism in front elevation as generally indicated by the line 1-1 in Fig. 2.

Fig. 2 is a vertical sectional view of the same apparatus, taken as indicated at 2 2 in Fig. 1.

Fig. 3 is a plan view of the separatory vessel and associated structure taken as indicated at 3 3 in Fig. 1.

Fig. 4 is an enlarged detail sectional View of the rake and an adjacent portion of the vessel, showing the rake at the mid-point of its travel in one direction.

Fig. 5 is a diagrammatic view of the automatic control for the operating mechanism.

Our improved separatory apparatus comprises a vessel 6 of generally arcuate form in vertical section, a rake 7 movable back and forth in a generally arcuate path, as indicated by the arrows a, a', to move sunken material S from the bottom of the vessel to discharge outlets 8, 8 at the respective ends of the arcuate path, and a discharge weir 9 for material suspended in the liquid medium. Arranged within the vessel is a baiiie 10 encircling a pool 11 for iioating material F, and the rake 7 is mounted on one or more oscillatory supporting arms 12 which extend between the baffle and the sides 13 of vessel 6. The sup porting arms 12 extend for some distance in the general direction of the arcuate path of movement of the rake, as at 14, and thence radially with respect to such path, as at 15, to a pivotal mounting 16 above the vessel. A trough 17 extends from the discharge weir 9 for the oating material. When the rake 7 is at one end of its arcuate path of movement, as shown in Fig. l, trough 17 extends above the supporting arms 12, the arrange.- ment being such that the rake may be brought slightly above the discharge weir 9 for the floating material to carry the sink to the edge of weir S for discharge from the vessel without interference with either the float trough 17 or the baflie 10.

Vessel 6 is mounted on a suitable base frame 18. Sides 13 of the vessel preferably are flat and extend somewhat above the discharge outlets 8 to assist in guiding the sink into troughs 20 arranged adjacent the outlets at the respective ends of the arcuate path of the rake. Vertical supporting columns, comprising pairs of opposed channel irons 21, 21, are secured at opposite sides of the vessel or frame and extend for some distance above the vessel. Arranged for vertical movement within the crosshead guide channels provided by these columns are crosshead bearing blocks 22, 22, best shown in Fig. 2, xedly attached to screws 23, 23, which in turn engage chain sprockets 24 rotating in supports 24a attached to cross beam 25 fixed to the upper ends of channel irons 21, 21, with suitable bracing'such as provided by gusset plates 26. Channels V21, 21, preferably are braced to the frame 18, as by means of diagonal supports 27, 27.

The crossheadY bearing blocks carry the pivotal mounting for rake arms 12 and also a fixed mounting for baille 1G. In the specific construction shown, the pivotal mounting for the rake comprises an axle rod 28 extending into the crosshead bearing blocks. Rake arms 12 are fixed to axle rod 2S for oscillatory movement therewith as imparted by gear sector 29 fixed to the axle rod in cooperation with other mechanism to be described. Also fixed to axle rod 28 is a counterweight 72 which balances the weight of the rake and its supporting arms about the axis of oscillation, decreasing the amount of power required for operating the rake. The fixed mounting for baie 10 comprises a pair of angle brackets 30 each having a horizontal arm resting on the respective crosshead block 22 and a pair of legs 31, 31, straddling axle rod 28, these legs being secured to upward extensions 32, 32 of side walls of the baffle. The chain sprockets 24 at the upper ends of screws 23, 23 are connected by drive chain 33. A bevel gear 34, as part of one of the sprockets 24, meshes with another bevel gear 35 fixed to rod 36 mounted in bearings suitably supported on beam 25. A chain drive 37 turns rod 36 in either direction to raise and lower crosshead blocks 22, 22, through the drive mechanism justdescribed, as desired. When these blocks are raised, they carry with them both the rake 7 and baffle 10 so that these elements can be lifted free and clear of the vessel 6, for cleaning and repairs.

The mechanism for operating the rake comprises,.in addition to gear sector 29 to which reference has been made, a rack 38 meshing with the gear sector and fixed to piston rod 39 of a double-acting air or hydraulic cylinder 40 mounted on a support 41 carried on a bracket 42 fixed to one of the columns made up of channel irons 21, 2l. Also mounted on support 41 is a pair of channel irons 45, 45, engaged by C- shaped slides 46, 46 which have threaded engagement with an adjusting rod 47, one end of which is threaded right-hand and the other lefthand. This adjusting rod is mounted for rotation in a bearing block V48 and held against endwise movement relative' thereto by suitable collars or thrust bearings. B y turning a hand wheel 49 fixed to the adjusting rod 47, slides 46, 46 can be moved closer together or farther apart to positions selected for automatic control of the oscillatory movements of rake 7. Each of the slides 46 carries a normally open electric limit switch, one ofwhich wefhere designate 50 and the other S1. These switches are operated by a stop 52 fixed to piston rod 39 in such position that when rake 7 is at the mid-point of its oscillation, stop 52 will be half way between switch 50 and switch 51.

ln Fig. we have illustrated diagrammatically one form'of-automatic control for the rake operating mechanism.'-` `The ends of operating cylinder 40 are connected, respectively, by' uid conduits 43 and 44 to speed control valves 53 and 54; `and thence through master control 4 valves 55 and 56 to a manifolded fluid pressure source indicated at 57. The electric limit switches selectively operate master control valves 55 and 56 through solenoids 58 and 59, actuating valve 60. The closing of limit switch 50 by stop 52 at the end of the upward movement of rack 38 has actuated solenoid 58 to move the piston assembly 61 of valve 60 into the position shown in Fig. 5, where it will remain until the other limit switch, 51, is closed. In this position master valve 56 is connected to the source of uid pressure 57 through valve 60. This has opened valve 56 to admit fluid under pressure from conduit 57 into conduit 43, and has operated valve 55 to permit fluid to low from conduit 44 to exhaust conduit 62. Thus, under the conditions stated high pressure fluid enters the upper end of cylinder 40, and low pressure fluid flows from the lower end of such cylinder, causing piston rod 39 to be propelled downwardly. This in turn results in moving rake 7 in the direction of arrow a. As the rake reaches the limit of this movement, i. e. the position shown in Fig. l, the other limit switch, 5l, is closed, actuating solenoid 59. This moves piston assembly 61 of valve 60 to the right as viewed in Fig. 5 and the entire operation described above is reversed. In this manner the rake is caused to oscillate slowly back and forth through the separatory vessel.

In our preferred construction shown, the blade 63 of the rake (cf. Fig. 4) is pivotally mounted at 64 on section 14 of supporting arm 12 with the free edge of the blade adjacent the inner surface of the vessel-or in this case against a rubber lining 65 comprising such inner surface. The blade 63 preferably is T-shaped in cross-section and may have rubber wiper strips 66 forming its free edge. Stops 67, 67 projecting inwardly from supporting arms 12 engage the ends of the rake to limit the extent of its movement around pivotal mounting 64. Moving. in the direction of arrow a the blade 63 assumes the position shown in Fig. l.. Moving .in the direction of arrow a', it assumes the position shown in Fig. 4. Note the favorable angle of inclination of the blade for discharge of sink into trough 20 as depicted in Fig. 1. Due to the pivotal mounting, an equally favorable angle of inclination Vis obtained when the rake reaches its limit of movement in the opposite direction. Material to be processed in the separator may be fed into the vessel by a chute 68 mounted by a bracket 69` on frame 18. In Figs. 2 and 3 may be noted extensions 70 and 71 of the sink discharge troughs 20 and float discharge trough 17, respectively. Trough 17 fits into extension 71 in such a way that when the rake and bae with associated trough structure are lifted by means of the mechanism earlier described, trough 17 freely disengages itself from extension 71.

The speed of operation of the rake may be varied in accordance with the type of material being processed, i. e. in relation to the normal time required for separation, rate of feed, etc. For example a speed of 8 discharges per minute, or 4 discharges to each side per minute may be considered satisfactory for most purposes. The speed control valves 53 and 54 are adjustable to give the desired speedof operation for particular conditions to be met in a particular instance.

The terms and expressions Vwhich We have employed are used ina descriptive and not a limiting sense, and we have no intention of excluding such equivalents of theinvention described, or of portions thereof, as fall within the purview of the claims.

We claim:

l. Apparatus for gravity separation of materials in liquid media, comprising a vessel to contain a pool of liquid medium, said vessel being of generally arcuate form in vertical section, a rake mounted for oscillation Vwith reference toa horizontal axis located above the surface of the pool so that the rake moves in a generally arcuate'path ladjacent'the inner surface of the vessel,

discharge outlets at the respective ends of said arcuate path, said rake serving to move sunken material from the bottom of the vessel to said discharge outlets, and a. discharge Weir for material suspended in the liquid medium.

2. Apparatus for gravity separation of materials in liquid media, comprising a vessel to contain a pool of liquid medium, said vessel being of generally arcuate form in vertical section, a rake suspended from a pivotal mounting located above the surface of the pool to move back and forth along the inner surface of the vessel, discharge outlets at the respective ends of the arcuate path of movement of the rake, said rake serving to move sunken material from the bottom of the vessel to said discharge outlets, and a discharge weir for material suspended in the liquid medium.

3. Apparatus for gravity separation of materials in liquid media, comprising a vessel which is of generally arcuate form in vertical section, a bafe encircling a pool for oating material within the vessel, a discharge Weir for the floating material, said discharge Weir being connected to said baille and arranged in communication with the pool of floating material encircled by said baffle, and a rake suspended from a pivotal mounting located above the surface of the pool to move back and forth in a generally arcuate path along the inner surface of the vessel to move sunken material from the bottom of the vessel to discharge outlets at the respective ends of said arcuate path, said rake being mounted on an oscillatory supporting arm extending between said baille and the sides of said vessel.

4. Apparatus for gravity separation of materials in liquid media, comprising a vessel which is of generally arcuate form in vertical section, a bae encircling a pool for floating material within the vessel, a discharge Weir for the floating material, said discharge weir being connected to said baie and arranged in communication with the pool of floating material encircled by said bafe, a rake suspended from a pivotal mounting located above the surface of the pool to move back and forth in a generally arcuate path along the inner surface of the vessel to move sunken material from the bottom of the vessel to discharge outlets at the respective ends of said arcuate path, said rake being mounted on an arm which extends for some distance in the general direction of said arcuate path and thence radially with respect to such path to said pivotal mounting above said vessel, and a trough extending from said discharge Weir for floating material, said trough extending above said arm 6 when the rake is at one end of its arcuate path of movement.

S. Apparatus for gravity separation of materials in liquid media, comprising a vessel which is of generally arcuate form in vertical section, a bae encircling a pool for floating material within the vessel, a discharge Weir for the oating material, said discharge weir being connected to said baflle and arranged in communication with the pool of floating material encircled by said bale, a rake suspended from a pivotal mounting located above the surface of the pool to move back and forth in a generally arcuate path along the inner surface of the vessel to move sunken material from the bottom of the vessel to discharge outlets at the respective ends of said arcuate path, said rake being mounted on an arm which extends for some distance in the general direction of said arcuate path and thence radially with respect to such path to said pivotal mounting above said vessel, and a trough extending from said discharge weir for floating material, said trough extending above said arm when the rake is at one end of its arcuate path of movement and said arm extending between said baie and the sides of the vessel.

6. Apparatus for gravity separation of materials in liquid media, comprising a vessel which is of generally arcuate form in vertical section, and a rake suspended from a pivotal mounting located above the surface of the pool to move back and forth in a generally arcuate path along the inner surface of the vessel to move sunken material from the bottom of the vessel to discharge outlets at the respective ends of said arcuate path, said rake comprising a supporting arm and a blade extending at right angles to said arcuate path, said blade being pivotally mounted on the supporting arm with the free edge of the blade adjacent the inner surface of the vessel, and stops on said supporting arm to restrict pivotal movement of the blade in either direction.

7. Apparatus for gravity separation of materials in liquid media, as defined by claim 6 in which said blade is substantially T-shape in cross section.

References Cited in the le of this patent UNITED STATES PATENTS 1,778,256 Hueber Oct. 14, 1930 FOREIGN PATENTS 14,928 Great Britain of 1913 496,249 Belgium June 30, 1950

Claims (1)

1. APPARATUS FOR GRAVITY SEPARATION OF MATERIALS IN LIQUID MEDIA, COMPRISING A VESSEL TO CONTAIN A POOL OF LIQUID MEDIUM, SAID VESSEL BEING OF GENERALLY ARCUATE FORM IN VERTICAL SECTION, A RAKE MOUNTED FOR OSCILLATION WITH REFERENCE TO A HORIZONTAL AXIS LOCATED ABOVE THE SURFACE OF THE POOL SO THAT THE RAKE MOVES IN A GENERALLY ARCUATE PATH ADJACENT THE INNER SURFACE OF THE VESSEL, DISCHARGE OUTLETS AT THE RESPECTIVE ENDS OF SAID ARCUATE

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