US3306671A - Method and apparatus for feeding material handling devices - Google Patents

Description

Feb. 28, 1967 J. N. J. LEEMAN 3,306,671

METHOD AND APPARATUS FOR FEEDING MATERIAL HANDLING DEVICES Filed April 19, 1965 4 Sheets-Sheet 1 FiGA By C SHMfl/V imes! 4 Cushwmv Feb. 28, 1967 J. N. J. LEEMAN 3,306,671

METHOD AND APPARATUS FOR FEEDING MATERIAL HANDLING DEVICES Filed April 19, 1965 4 Sheets-Sheet 3 Feb. 28, 1967 J. N. J. LEEMAN METHOD AND APPARATUS FOR FEEDING MATERIAL HANDLING DEVICES Filed April l9, 1965 4 Sheets-Sheet 5 FIG.4

FIG.5

INVENTOQ JHN N. J. LEEMHN By CUSHMAN, DHRBY CusHMH/V HTTDRN E Y5 1967 J. N. J. LEEMAN METHOD AND APPARATUS FOR FEEDING MATERIAL HANDLING DEVICES Filed April 19, 1965 4 Sheets-Sheet 4 1w ve/v TOR JAN M J1 A EEMA N B CUSHMHNHDARBY g Cl/sHMfl/V ATTaR/vEvs United States Patent 3,306,671 METHOD AND APPARATUS FOR FEEDING MATERIAL HANDLING DEVICES Jan N. J. Leeman, Heerlen, Netherlands, assignor to Stamicarbon N.V., Heerlen, Netherlands Filed Apr. 19, 1965, Ser. No. 448,962 8 Claims. (Cl. 302-14) The present invention relates to the feeding of particulate materials to various material handling and separating devices, such as devices for classifying or size or specific gravity separations. More particularly, the present invention relates to technique and means for feeding a plurality of such separating devices with a mixture of constant composition for the individual material handling and separating devices.

When a plurality of material handling devices, ope-rating in parallel, are fed from a common supply of the material to be treated, there is a problem involved in ensuring and maintaining a predetermined composition and volume rate of feed to the individual devices. For example, when particles to be separated according to specific gravity are fed to a number of separator devices, such as washing tables, it is possible to use a manifold of feed pipes branching from a common supply conduit. The feed rate and composition of the mixture nevertheless tend to differ from one separator to another. There-. fore, the potential benefits of having a main supply conduit point of selection of the mixture feed rate and composition to provide the most favorable separation conditions in each individual separator are not, in fact, realized. Furthermore a nonhomogeneity of the feed composition supplied to the individual separator devices will arise when different quantities are fed thereto, e.g. when separator devices of different capacities are employed in the same group.

It is therefore a principal object of this invention to provide an improved feeding device and method that will supply particulate solid materials to a plurality of material handling devices in a homogeneous fashion. It is another object of this invention to provide an improved method and device for feeding particulate materials to a plurality of material handling devices in respective quantitles and at rates corresponding to the respective capacity of the devices, which maintain the same composition of the material fed to each individual device.

A more specific object of this invention is to provide a feeding device having a radial symmetrical chamber in which the material to be treated is fed so that it is placed in rotation about the axis of the chamber, and continuously discharging the material from the chamber through a plurality of discharge openings which are disposed at a common radius and at or near the periphery of the bottom of the chamber.

It is still another object of this invention to provide a feeding device in which the quantity of particulate material discharged through the individual discharge passages may be varied, while maintaining the separate fractions discharged through such individual passages of equivalent composition.

Still a further object of the present invention is to provide a material feeding device in which a liquid medium is tangentially introduced into a radially symmetrical chamber to impart a rotational movement to the material fed into said chamber.

These and other objects of the invention will become apparent to those skilled in the art when reference is had to the following description and drawings.

In the drawings:

FIGURE 1 represents a flow-sheet showing the main features of one embodiment of the invention;

FIGURE 2 is a view in vertical cross-section of one embodiment of a distribution feeding device according to this invention;

FIGURE 3 represents a top view of the device of FIGURE 2, partly cut away;

FIGURE 4 represents a view on vertical cross-section of another embodiment of the distribution and feeding device according to this invention;

FIGURE 5 represents a top view partly cut away of the embodiment of FIGURE 4;

FIGURE 6 represents a view in vertical cross-section of still another embodiment of a distribution and feeding device according to the invention; and

FIGURE 7 represents a top view partly cut away of the embodiment shown in FIGURE 6.

Referring now to FIGURE 1 of the drawings, particulate solid material to be processed, e.g., separated according to specific gravity, for example raw coal, is supplied at 1 in dry condition to a distribution and feeding device including a tank 2. Liquid, for example water, is'fed tangentially through one or more conduits 3 into tank 2 so that a rotary current is produced therein.

As shown in FIGURE 2 the distribution tank 2 may comprise a central tube 4 to which the solid particulate material is supplied by means of a belt conveyor 5. When the material is supplied in a more or less wet condition it may also be supplied by means of an inclined chute 5' as indicated in dotted lines at the left hand side of the figure. The central tube 4 opens at its lower end into the tank 2 at a level below the entrance of the tangential feed pipes 3. The tank comprises an inverted truncated vessel 6, having an upper cylindrical portion 7. Preferably equally spaced about its periphery, and at the same height above the bottom 8 of the tank, a plurality of feed pipes 3 are provided for introducing the separating liquid tangentially into the upper portion of the truncated part 6 of the tank. The bottom of the tank is provided with a number of outlet openings 9, arranged at a common radius and preferably equally spaced about the circle defined by this radius.

Due to the rotary movement of the mixture of solids and liquid in the tank the composition of the mixture will typically vary along horizontal radii, but will be constant for a certain radius. By positioning the outlet opening 9 at a common radius, the fractions leaving the various openings are equal in composition. The outlet openings are preferably also provided with nozzles 10 of equal inner diameter. Thus, the quantities of material passing through the passages defined by these nozzles will also be about equal.

The nozzles 10 may also be arranged for interchangeably inserting nozzles with different inner diameters. By changing the nozzle size, the relative quantities of the fractions passing through the several nozzles may be varied as desired. A further advantage of providing the interchangeable nozzles is to permit replacement of the nozzles in the case of abrasion of the outlet openings 9.

The nozzles may be inserted into a recess 11 of the bottom of tank 2 so that the upper surfaces of the respective nozzles lie in a common plane with the upper surface of the tank bottom. Thus the rotational move ment of the mixture is not disturbed by the presence of the nozzles.

The bottom of the tank 2 may also be provided with an upwardly pointing central conical core 12. This core 12 helps prevent the occurrence of vertical eddy currents in the rotating mixture, which currentscould have an unfavorable influence upon the equal distribution of the material over the various outlet passages 9.

It is also possible to arrange the outlet openings in the outer Wall of the tank, as shown in FIGURES 4 and 5.

Referring now, again, to the flow-sheet shown in FIG- URE l, the fractions discharged through the outlet openings 9 are conducted through conduits 13 to a number of separator devices 14, such as jig washers, tables, hydrocyclones, or the like. The ratio between the crosssections of the passages of the nozzles 10 is chosen in correspondence with the ratio between the capacities of the various specific gravity separators, so that all separators are loaded correspondingly. Preferably identical separators will be used, so that nozzles 10 of the same diameter may be inserted into the recesses 11 (as shown in FIGURE 2).

In the separator devices 14 the raw coal may be separated into a clean coal fraction, which leaves the separators 14 through a conduit or chute 15 and a clean shale fraction, which leaves the separators through a conduit or chute 16. These fractions have to be dewatered to recover the water for reuse and to obtain the clean fractions in a substantially dry condition.

In the example shown in FIGURE 1, a plurality of dewatering devices 17 of equal capacity areused to dewater the clean coal fractions of the separator devices 14, whereas one dewatering device 18 is applied for the shale fractions. In order to divide the clean coal fractions equally over the three dewatering devices 17, the fractions may be supplied tangentially into a distributing tank 2, through one or more conduits 19. Each of the conduits 15 may directly communicate with one of the feed pipes 19, so that the distribution tank 2' is supplied at a plurality of places, preferably equally spaced about its periphery. It is, however, also possible to arrange the system so that two or more conduits 15 lead to a single feed pipe 19.

In the embodiment shown in FIGURES 4 and 5 only one feed pipe 19 is shown, but as stated above there may be more than one such pipe. The distribution tank 2 consists of an upper cylindrical portion 20, provided with feed pipe or pipes 19 and opening at its lower end into a cylindrical portion 21 of larger diameter. As the distribution tank is fed from a part of the installation, which may be arranged at a higher level than the tank, the cylindrical part 20 is preferably closed at its top by a cover 22. The outer wall of the lower cylindrical portion 21 is provided with a plurality of outlet openings 23, preferably of equal diameter, preferably arranged adjacent the bottom 24 and spaced equally over the circumference of the outer cylindrical wall of portion 24. The mixture of clean coal and water leaves the tank 2' through the preferably radially-arranged conduits 25 which are provided in turn with nozzles 26 of preferably equal inner diameter. It is also possible to have these conduits 25 tangentially disposed, provided they have a direction in correspondence with the direction of rotation of the mixture in the tank 2', as may be established by the tangential supply of material through the feed pipes 19.

As a result the amount of clean coal and water from the separator devices 14 may be divided into a plurality of fractions of equal concentration and quantity, on leaving the tank 2' so that the individual dewatering devices 17 for the coal fractions are equally loaded. Each dewatering device may comprise a stationary curved bar screen 27 on which the bulk of the water in the mixture fed by one of the conduits 25 is removed. Subsequently the overflow of each bar screen is passed over a vibrating screening deck 28 to remove as far as possible the water still adhering to the coal particles. The dewatered coal is discharged at '29, whereas the liquid removed by the screening action is received in tanks 30 provided below the screens. From the tanks the liquid is supplied through conduits 31 to a settling tank 32. In this tank the fine solid particles which have passed the screens settle out and are discharged at 33. The clarified overflow of the settling tank is returned by means conduit 16 are passed over a curved bar screen 35 and subsequently over a vibrating screen 36. The dewatered shale fraction is discharged at 37, whereas the separated water is received in a tank 38 positioned below the screens and passed through a conduit 39 to the settling tank 32.

As the amount of shale in the raw coal is smaller than that of the coal, it is assumed that one dewatering device will be sufficient for the shale fraction. If two or more dewatering devices will be necessary, the shale fractions from the specific gravity separators may be fed into a distribution tank and divided into equal quantities and equal composition over the 'dewatering devices in the same Way as described for the coal fraction.

Instead of using vibrating screens for the final dewatering of the fractions centrifugal separators may also be used.

In the embodiment shown in FIGURES 6 and 7 the distribution tank 2" comprises a cylindrical portion 40 which is divided by a partition wall 41 into an upper compartment 42 and a lower compartment 43. Both compartments communicate with each other through a central passage 44. The actual cross-section of the passage may be varied by mounting a plate 45 having a central opening 46 of the desired diameter on the partition wall 41. This plate may be manufactured of material having a high resistance to abrasion.

The mixture to he distributed is fed tangentially into the upper compartment through a conduit 47, creating a rotational movement. This movement continues in the lower compartment 43, in which the formation of circular layers of constant composition takes place. Due to the provision of the partition wall 41, disturbance of this layer formation by turbulences caused by the introduction of material through conduit 47 is avoided. Such turbulence is especially likely in the event that the level 48 of the medium in the tank compartment 42 is below the opening of conduit 47.

Furthermore, the mixture of material is now forced to fiow to the center of the tank towards the passage 46 from where it spirals down into the lower compartment, thus giving the mixture an unhindered opportunity to build up the desired cylindrical rotating layers.

The tank 2" may be provided at the top with a cover 49 and at its lower end with a bottom 50. The bottom is also provided with a number of spaced outlets 51 arranged at a common radius in which nozzles 52 are inserted in the same way as described in conjunction with FIGURE 2.

The invention isnot restricted to the application described above, but may be applied in various cases, where a mixture of solid and liquid are to he treated or processed in a number of devices of the same character. For example the invention may be employed when a slurry of solid material is to be dewatered on a number of filters. In another example the invention may also be employed in a specific gravity separation plant where the separating medium derived from the separated products has to be regenerated in a number of similar devices, for instance magnetic separators. It is further possible to create a mixture of solids in the appanatus described. For in stance in the example shown in FIGURE 2 materials of different kind may be introduced into the apparatus through belt 5 and chute 5' to be thoroughly mixed in the apparatus and discharged in this condition through the outlet openings 9 to a number of material handling devices, for instance chemical reaction vessels, in which the components of the mixture have the opportunity to react with each other or may he further processed.

While the embodiments of the present invention as herein disclosed, constitute preferred forms, it is to be understood that other forms and embodiments constructed in accordance with the same principles may also be 5 adopted, all coming within the scope of the appended claims.

What is claimed is:

1. Apparatus for dividing a stream of particulate material feed into a plurality of particle feed streams which comprise a chamber having a central axis, conduit means for feeding the said stream of particulate material axially into said chamber, feed pipe means for introducing a liquid medium into said chamber and to cause rotation thereof about said central axis, and a plurality of egress means arranged on a common radial distance from said axis and to permit egress of a plurality of said particle feed streams.

2. Apparatus according to claim 1, wherein said radia ly symmetrical chamber has the form of a truncated cone, and said discharge passages are located in the base thereof.

3. Apparatus according to claim 1 wherein the bottom of said radially symmetrical chamber includes an axially disposed cone member, having an upwardly pointing apex.

4. Apparatus according to claim 1 including means for adjusting the size of the discharge openings.

5. Apparatus according to claim 4, including interchangeable nozzles of difiFerent sizes for insertion into said outlet passages.

6. Apparatus according to claim 1 wherein said discharge openings are each of the same predetermined size so that each of said devices receives a composition of the same feed at the same rate.

7. The apparatus according to claim 1 wherein said discharge openings are of a predetermined variation in size so that each of said devices receives a feed of the same composition but at predetermined different rates.

8. In a separating plant having a plurality of material separating devices, a radially symmetrical distribution vessel, means for intdoducing a feed stream of particulate material to he separated into said vessel, a generally tangential inlet pipe means for introducing a liquid medium into said vessel, a plurality of discharge openings radially equidistant from the axis of said vessel and provided in the lower end thereof and for discharge of a plurality of streams of said material of comparable composition, and means for delivering said last-mentioned streams of material to a plurality of separator devices.

References Cited by the Examiner UNITED STATES PATENTS 1,674,454 6/19'28 Smith 30228 1,754,124 4/1930 Skentlberg et al, 302-28 1,825,668 10/1931 Kennedy 30228 2,474,477 6/1949 Hague 30228 ANDRES H. NIELSEN, Primary Examiner.

Claims (1)

1. APPARATUS FOR DIVIDING A STREAM OF PARTICULATE MATERIAL FEED INTO A PLURALITY OF PARTICLE FEED STREAMS WHICH COMPRISE A CHAMBER HAVING A CENTRAL AXIS, CONDUIT MEANS FOR FEEDING THE SAID STREAM OF PARTICULATE MATERIAL AXIALLY INTO SAID CHAMBER, FEED PIPE MEANS FOR INTRODUCING A LIQUID MEDIUM INTO SAID CHAMBER AND TO CAUSE ROTATION THEREOF ABOUT SAID CENTRAL AXIS, AND A PLURALITY OF EGRESS MEANS ARRANGED ON A COMMON RADIAL DISTANCE FROM SAID AXIS AND TO PERMIT EGRESS OF A PLURALITY OF SAID PARTICLE FEED STREAMS.

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