US2771994A - Apparatus for separating materials of different specific gravities - Google Patents

Description

APPARATUS EOR SEPARATING MATERIALS OF DIFFERENT SPECIFIC GRAVITIES Filed NOV. 13, 1952 IN VEN TOR.

BY WM 55W United States Patent APPARATUS FOR SEPARATING OF DIFFERENT SPECIFIC GRAVITIES William P. Connelly, Philadelphia, Pa., assiguor to United Engineers & Constructors Inc., Philadelphia, Pa., a corporation of Pennsylvania Application November 13, 1952, Serial No. 320,265

4 Claims. (Cl. 209172.5)

This invention relates to improvements in apparatus for separating materials of difiering specific gravities and more particularly to the type of separating apparatus which includes a suitable vessel, conventionally of conical form, containing a fluid flotation medium in which by reason of the aforesaid differing gravities of the components of the work material the desired selective separation is obtained. Apparatus of this class is described, for example, in United States Patent No. 2,222,030, and in my copending application for United States Patent Serial No. 290,057.

When separating materials of ditfering specific gravities containing relatively high percentages of near gravity particles, i. e., particles whose specific gravity is only slightly higher than the specific gravity of the fluid separating medium, the slow falling velocity of these particles in the fluid medium tends to cause a progressive accumulation of this material in the vessel. The accumulation if not corrected may eventually result in undue quantities of the near gravity materials being discharged with the float product from the top of the vessel.

The present invention provides a simple and elfective means for avoiding such accumulations of near gravity particles and the resultant discharge of the particles with the float product.

The device is illustrated in the attached drawing which shows more or less diagrammatically a conventional type of separation vessel made in accordance with the present invention. In the drawings the reference numeral 1 designates the separating vessel operating in accordance with the principles set forth above and conventional in all respects except in the provision of a transfer duct 2 which communicates at its upper and lower ends respectively with ports 3 and 4 in the side of the vessel. The locations of these ports are not critical but in general the port 3 will be placed in the upper part of the vessel in the area where the aforesaid accumulations are to be provided, and the port 4 will be in the lower discharge area of the vessel from which the materials of higher specific gravities are removed. The duct 2 has at its lower end a nozzle port 5 from which a pipe 6 extends to a source 7 of pressure water which may be a part of the water circulating system of the apparatus. A valve 8 controls and regulates the flow of water through the pipe 6. In the present instance the nozzle port 5 is directed toward the lower port 4.

In operation water under pressure discharged through the pipe 6 from the source 7 tends to evacuate the upper end of the duct 2 and thereby sets up a flow through the duct from the upper end to the lower. This flow withdraws a part of the fluid mass from the upper part of the vessel including accumulated near gravity materials and transfers this fluid mass to the lower part of the vessel for discharge with the deposited mass of high gravity material in that area.

Let it be assumed that the work material contains a relatively high percentage of the near-gravity" materials .referred to above, that is to say, materials whose specific 2,771,994 Patented Nov. 27, 1956 gravity is only slightly greater than that of the flotation medium in which the separating process occurs, and that it is desired to separate this near gravity material from the float material which is continuously withdrawn from the upper layers of the material in the vessel. The slow settling of the near gravity material in the vessel will result normally in a progressively increasing accumulation thereof in the upper areas of the vessel and eventual removal thereof in undesirable quantity as a contaminant with the float material. The device of the present invention, described above, accelerates movement of the"near gravity material from the upper areas of the vessel to the lower or discharge areas, and thereby prevents undue accumulations of the material in the areas from which the float material is withdrawn.

It is evident that the device in principle is susceptible to a reversal of flow for the purpose of continuously augmenting the normal accumulations of the middlings of near gravity material in the upper areas of the tank for removal with the float material in substantially larger than normal quantities where such removal may be found desirable. It will be noted also that whereas in the illustrated embodiment the lower end of the duct 2 communicates with a lower area of the separating chamber proper within the vessel 1, it may, without departure from the principle of the invention, be connected at another point in the apparatus, such, for example, as to the refuse chamber 9. The term vessel as used in the claims therefor is used in the broad sense as embracing the chamber 9 and those immediately associated parts of the apparatus to which the lower end of the duct might be attached without essential change of function. y

I claim:

1. In separating apparatus of the type set forth, the combination with a separating vessel containing a fluid separating medium or predeterminable specific gravity, of means for introducing work materials into said fluid medium, means for discharging lower specific gravity components of the work material from the upper area of the vessel, means for discharging components of the work material of relatively high specific gravity from the lower area of the vessel, and means for withdrawing from the body of the fluid mass in the vessel the components of the work material of intermediate specific gravities accumulating in an area between said discharge areas and for forcibly transferring the components so withdrawn to another area in closer proximity to one of said discharge areas.

2. In separating apparatus of the type set forth, the combination with a separating vessel containing a fluid separating medium of predeterminable specific gravity, of means for introducing work materials into said fluid medium, means for discharging lower specific gravity components of the work material from an upper area of the vessel, means for discharging components of the work material of relatively high specific gravity from a lower area of the vessel, and means for accelerating the movement of the work material of intermediate spe cific gravities from the said upper to the said lower areas of said vessel for discharge with the material of relatively high specific gravity, said accelerating means comprising a duct connecting an area of said vessel intermediate said discharge areas, and means for creating a downward flow of the fluid mass in the vessel through said duct.

3. A separating vessel of the character set forth comprising discharge means operatively associated with upper and lower areas respectively of the vessel, and wherein work material deposited in the vessel has substantial freedom for direct gravitational movement between said discharge areas, a duct communicating at one end with the interior of the vessel below and in relatively close proximity to the upper discharge area and in the path of said gravity movement of the Work material, said duct communicating at the other end with the interior of the vessel at a point below the first namedv end and relativelyremote to said upper discharge area and alsoin the path of said gravity movement, and means for setting up a forced circulation through said duct of a fluid flotation medium contained Within the vessel.

4. In separating apparatus of the type set forth, the combination with a separating vessel containing a fluidseparating mediumv of ,predeterminable specific gravity, of means for introducing work materials into said fluid medium, means for discharging lower specific gravity components oftthe work material from the upperarea of the vessel, means for discharging components of the work material of relatively high specific gravity from the lower area of the vessel, and means including a duct opening at oppositeends respectively to an area of the vessel intermediate said discharge areas and with another area in closer proximity to one of said discharge areas for intercepting the components of the work material of intermediate specific gravities tending to accumulate in said intermediate area and for forcibly transferring said components to said other area.

References Cited in the file of this patent UNITEDiSTATES PATENTS Germany June 29,

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