US2777736A - Hydraulic conveyor with granular slurry control valve - Google Patents

Description

INYENTOR.

5 w L N m my. B. A v H R A H Jan. 15, 1957 H. B. CANNON A HYDRAULIC coNvEYoR WITH GRANULAR sLURRy CONTROL VALVE Filed NovA 20, 1953 United States Patent O HYDRAULIC CGNVEYOR WITH GRANULAR SLURRY CONTROL VALVE Harry B. Cannon, Lakeland, Fia.

Application November 20, 1953, Serial No. 393,359

Claims. (Cl. 302-14) This invention relates to a control system for controlling the flow of mixed media. More particularly, the invention relates to a novel system for underwater mining operations. Specically, the invention relates to a pumping system including control valves for providing, controlling and maintaining a constant density from a source of mixed media to an apparatus for separating the same in any desired manner.

It is a well-known and conventional expedient to use various types of gravity separators for stratifying and isolating separate fractions of granules of dilerent specic gravities, as for example, various types of sands, minerals and grains. In practice, the separators may comprise any of many well-known and diversiiied types including the pinched sluice form and the Humphreys spiral. In each case the preferred method for separating granular media is by gravity stratification of a slurry in which the media is suspended. However, regardless of the type separator employed, it is an essential feature to successful and efficient operation that the slurry density and volume be maintained constant, or as nearly constant as is practical at all times. This condition becomes particularly critical in continuous mining operations in which slurries must be transported from a dredging or storage point to an operating station through long horizontal lines. The ineiciency caused by varying slurry densities may be substantially reduced by the use of specially constructed separator apparatus, as set forth in my copending application, Serial No. 297,952, led Iuly 9, 1952, but on the whole cannot be completely eliminated.

One crucial consideration in continuous underwater mining operations is the provision of adequate surge capacity in the apparatus to permit coordination between the dredging or mining stage, the roughing or trash separation stage, the valuable feeding stage, and the valuables classification stage. This will be understood when cognizance is taken of the fact that an average mining rate of 1000 gross tons per hour comprises intervals of operation in which differing fractions of water and mineral are fed from the dredge to the classiers, and because of which it has been necessary to employ a storage station intermediate the mining and classification stages in order to obtain a uniform feed to the classifying apparatus. Such innovation, however, does not provide the desired efficiency in the classifiers without employment of additional structure for controlling the density and rate of feed to the classiers. Contemporary arrangements directed towards this end have not proven satisfactory because of a failure to supply a substantial surge capacity without also producing sanding in the feed lines, pumps and control valves.

Various attempts have been made to provide suitable simplied means for controlling the slurry density but all have failed in practical operation. One of the primary reasons for the inef'ricacy of the prior art devices has been a failure to provide an inexpensive, simplilied structure suitable for use with various modes of storing mixed media, while permitting a ready and rapid control over 2,777,736 Patented Jan. 15, 1957 changes in density in the discharge circuit. Until the advent of the present invention, no one had succeeded in controlling the density of granular slurries without employing separate feed structure for each of the variuos slurry components. This delciency is of critical significance in continuous underwater mining operations.

Accordingly, a main object of the present invention is to provide an inexpensive, simplified structure for maintaining a predetermined density and ow rate in a mixed media ow. A further object of the invention is to provide means for automatically maintaining the density and volume within a predetermined range. Another object of the invention is to provide a valved discharge system for mixed media employing interrelated valving for controlling the ow of the media components. A still further object of the invention is to provide a control system for mixed media which is applicable to any usual form of storage arrangement and which is of particular eicacy in continuous underwater mining operation. Other and distinct objects of the invention will become apparent y from the description and claims which follow.

A preferred modification of the invention may be brieflly described as comprising a pumping system which supplies mixed media from a storage area to a battery of separators in which the pumping element acts as a primary control and separate valving elements act as Vernier controls, all being directed to maintaining a predetermined constant density in the system. Another form of the invention may be generally described as comprising a system of the previously described type in which mea-ns are included for automatically operating the elements providing the main and/ or vernier control functions. A further form of the invention relates to a similar type control system including means for automatically diluting granular mixed media with a suitable uid vehicle in a predetermined manner to maintain a substantially constant density in a discharge circuit.

Having broadly described the generic aspects of the invention, reference will now be made to specific examples of the same in connection with the accompanying drawings, and in which the single ligure is a schematic View of one form of the invention.

In the embodiment of the invention illustrated in the figure, the control system is shown as being applied to a dredging operation in which a dredging barge traverses a river, ocean-, or lake-front, while systematically dredging the bottom to recover various types of mineral de posits. In accordance with the usual practice, the dredging barge is accompanied by, or alternatively includes, means for roughing out or separating unwanted materials from the valuable minerals. Generally, such means cornprises a roughing barge including means for transferring the dredged material to storage dunes or piles on the lake or river bottom and additional structure for selectively transferring the stored media to a roughing separator prior to transporting the same to a refinery for a nal processing. If desired, all of the necessary separating operations may take place at the site of dredging through the simple expedient of providing additional finishing separators; but this is only practicable where the dredging side comprises relatively rich deposits.

As shown in the ligure, the present invention is applied to such system in which a roughing barge includes means comprising a clam-shell bucket type conveyor having buckets adapted to discharge a continuous stream of dredged material to one side of the barge to form a storage pile or dune 17() on the bottom 165 of a lake, river, or the like 160. In accordance with the usual practice, a trash screen is positioned to intercept the discharged material as it leaves conveyor buckets 110 to separate trash such as limbs, logs, shells, rocks and the like. The conveyor 105 may comprise the dredge, per se,

or merely a secondary conveyor positioned to transfer the dredged material from a storage bin, barge, or the like. Barge 100 further includes a plurality of roughing batteries of gravity-type separators 121B (only one of which is illustrated) mounted on a suitable framework 127 and preferably comprising a series `of truste-conical cones 126 and inverted frusto-conicalpin'ched sluice units 125 in accordance with the disclosure set forth in my copending application, above identied, or in my prior application Serial No. 103,648, tiled Iuly 5, 1949, now Patent No. 2,644,583, dated July 7, 1953. As will be readily understood from reference to said copending application, the separating batteries- 129 are fed a continuous slurry of water and suspended granular material which flow down the distributing cones and frusto-conical sluices to be come gravity stratified and separate the valuable minerals and gangue materials; the valuable minerals being collected within a suitable basin or storage bin carried by the barge 100, and the separated gangue material being discharged from the barge as by a stream 129 through an outlet 'port 128.

In accordance with the present invention, the slurry of mixed media is supplied to the separator batteries 121) from a centrifugal pump 130 having an output or discharge line 131 connected to a T distributor 133, and via discharge spouts 134 (only one of which is illustrated) to the uppermost distributing cone 126 of batteries 120. The inlet side of centrifugal pump 130 is directly connected to the storage pile or dune 170 beneath the surface of the lake or river 160 by means `of an inclined conduit 135 terminating in an upturned vertical mouth or inlet opening 136 positioned in the center of the pile 170.

In accordance with the present form of the invention, conduit 135 is connected with an upstanding support member 137 which in turn is connected to a chain 139 depending from the barge through a port 138. Chain 139 is connected to a conventional type winch mechanism on the barge and is adapted to raise and lower conduit 135. Por this purpose conduit 135 may include a swivel connection at pump 130, or alternatively, may comprise a flexible hose elment, or a flexible intermediate section. In practice, it has been found that a relatively short flexible intermediate section in conduit 135 adequately serves the purpose, while at the same time allowing a necessary slight play between the inlet mouth 136 and pump 130 to accommodate the rolling and pitching of the barge as well as tidal changes in the level of the Water surface 169.

In order to control the flow of the material 176 through conduit 135 under the suction force of pump 130, the upwardly directed mouth 136 of the supply conduit is adapted to be selectively closed by a valve mechanism 1411. Valve unit 14) includes a plug valve 141 connected to a hollow valve stern 142 and supported for vertically directed reciprocating movement into and out of registry with mouth 136 by a stationary sleeve member 146 carried by support 137. With this arrangement, the open mouth 136 of conduit 135 serves as a valve seat, and in cooperation With plug valve 141 selectively controls the amount of mineral material 171! entering the conduit.v

Hollow valve stem 142 is bent at right angles at its upper end to provide a radial extension 143 which is adapted to project laterally through the dune or pile 170 into Contact with the water 160. This laterally directed conduit is provided with a butterfly control valve 145 for selectively opening and closing communication between the body of water 166 and a central outlet channel 144 in plug valve 141. It will be readily appreciated that the present arrangement provides a system for selectively diluting the granular media 171i as it enters conduit 135 to produce a slurry of a predetermined density.

Although not so illustrated, it is often desirable to construct extension conduit 143 as including an intermediate flexible section of tubing for facilitating reciprocation of valve stem 142 in the loosely packed mineral pile. Al-

ternatively, conduit may include a section of resilient or extensible material for the same purpose.

A pair of control levers 147 and 149 are connected to operate the respective plug and butterlly valves, lever 147 being xedly connected to valve stem 142 and pivotally mounted on support 137, While lever 149 is connected to rotate butterfly valve about its central pivot axis. Each valve control lever is further connected for remote actuation by means of a pair of control levers 150 and 155, respectively, carried by barge 10) through intermediate Bowden Wire connections 151 and 152. Thus, it will be understood that movement of levers 150 and 155 will be directly transmitted to valves 141 and 145. It will be further appreciated that this arrangement permits the ready control of both volume and density, levers 15) and 155 serving in an interrelated fashion to maintain the ow in conduit 135 at a specified rate of a specilied density.

Applicant has found, however, that the use of a centrifugal pump as the power source in the system greatly facilitates control of the volume flowing in the circuit through the simple expedient of inserting a control valve or pinch cock 132 on the outlet side of the pump. In such case, valve 132 serves as a main control on the pressure side of the pump for accurately maintaining the desired volume. At the same time, a Vernier control may be eX- erted through control levers 150 and 155, the relative metering of the two slurry components providing the desired rapid density control.

The above-described arrangement has proved exceedingly effective in practical operations in which substantially constant densities have been maintained in the slurry outflow from spout 134 over extended periods of operation. One of the important features of the present arrangement, and one which will be immediately recognized by those skilled in the art, is the application of the main control valve on the pressure side of the pump 130. By such arrangement, applicant permits the centrifugal pump to function in a most eicient manner while at the same time retaining a supervisory control at the suction side of the pump of such nature that it does not interfere with the pump eliciency. This unique arrangement far surpasses in elliciency those prior ineffectual attempts to provide full control on the suction side of the pump.

As will be readily understood by reference to the particular description of the separating units 125, as more fully set forth in said copending application, Serial No. 297,952, on my said prior patent, the slurry discharged from conduit 134 is separated into tailings which are discharged to waste through porthole 12S, middlings and a concentrate, the concentrate being retained for further processing and the middlings preferably being returned via a suitable launder to the storage pile 170. Although not necessary in most applications, it is sometimes desirable to employ an additional priming water ypump mounted on barge 100 and connected to the delivery line 135 via a control conduit, including a control valve in the line adjacent the priming pump and a discharge jet nozzle communicating with delivery line 135. With such an arrangement, initial main pump prime is readily facilitated by the jet injection of fluid from the primer line into suction conduit 134. Further, provision of the priming pump permits rapid freeing of delivery line 13S and main pump 130 from any inadvertent sanding.

The present invention is not limited to systems which employ centrifugal pumps, but the same may be used with other type pumps, as for example, reciprocal or diaphragm types. In such case, both total volume control and precise density control may be obtained throng the metering action of valves 141 and 145. Y

Obviously, a plurality of storage piles may be formed in a single pond or lake in combination with tandem delivery circuits to identical separating units, or .alternatively, to a common separating unit.

As many apparently widely dilerent embodiments of this invention may be made without departing from the spirit and scope hereof, it is to be understood that this invention is not limited, except as defined inthe appended claims.

What is claimed is: Y

l. A system for controlling the flow of granular slurries from a storage station containing packed granularvmaterial to an operating station comprising a conduit connecting said stations, a slurry pump in said conduit, valve means cooperating with said conduit at said storage station for selectively governing ow of granular material from said storage station into said conduit, a iluid passageway in said valve means normally communicating between said conduit and a source of uid, a metering control valve in said passageway, and control mechanism connected to said valve means -and said metering control valve for simultaneously supervising the ow of -granular material and uid in said conduit to maintain a slurry having a predetermined density.

2. A system as set forth in claim 1 in which said slurry pump is of the centrifugal type, and a main control valve in said conduit on the pressure side of said pump whereby said main control valve provides a rough control adjustment and said control mechanism provides a Vernier control adjustment in said slurry ow.

3. A system as set forth in claim l in which said source of uid is a natural watercourse and said storage station comprises a pile of vgranular material deposited on the bottom of said watercourse.

4. A system as set forth in claim 3 in which said valve means comprises a perforated plug valve and said uid passageway comprises a hollow valve stem connected with said plug valve.

5. A system for controlling the ow of granular slurries from a storage station containing a submerged pile of granular material in a body of liquid to an operating station, comprising a tubular conduit connected betweensuch stations, said conduit including a terminal opening in contact with said submerged granular material, valve means positioned within said opening of said tubular conduit and including a main valve having a terminal end adapted to enter and seal said open end of said conduit, structure supporting said valve means for movement to ward and-away from said opening to selectively control admission of granularmaterial from said submerged pile into said conduit, said valve means including a hollow valve stem communicating between said body of liquid and the terminal end of said main valve, a metering control valve in s-aid valve stem and interrelated control mechanism connected to said valve means and said metering control valve for governing the ow of said granular material and liquid through said conduit to maintain a predetermined density in the slurry therein formed.

References Cited in the lile of this patent UNITED STATES PATENTS 1,194,520 Lewis Aug. l5, 1916

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