US2952083A

US2952083A - Dredge construction

Info

Publication number: US2952083A
Application number: US600449A
Authority: US
Inventors: John H Forkner
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-07-27
Filing date: 1956-07-27
Publication date: 1960-09-13
Anticipated expiration: 1977-09-13

Description

United States Patent DREDGE CONSTRUCTION L John H. Forkner, Rte. 13, Box 531, Fresno, Calif.

" Filed July 27, 1956, Ser. No. 600,449

4 Claims. ((11. 37-71 1 This invention relates generally to dredges of the type generally carried by pontoons or barges and adapted to operate on underwater formations. In particular the invention is applicable where it is desired to recover mineral values contained in the formation.

In the past dredges of the endless bucket line type have been used to remove underwater formations for treatment to recover gold or other mineral values. Such equipment isrelatively costly and its use is prohibitive except in relatively few locations where warranted by proven mineral values. The high cost is due largely to the extensive bucket line and its supporting ladder, and the relatively large barge required to float the working parts. In the operation of such dredges, as in the operation of barge mounted scoops or shovels, the buckets containing the removed material are lifted out of the water, and this characteristic must be taken into account in designing the size of barge employed, and the power requirements. Efforts have been made to use dredges of the suction type in gold dredging and like operations. Such dredges have the theoretical advantage that the underwater operating parts need not be lifted above the water level for discharge of the dredged solids, and therefore the size of the barge or pontoons employed may be reduced accordingly. In addition the over-all construction of such suction dredges is relatively simple compared to the dredgw of the bucket line type. However the performance of suction dredges as heretofore constructed have been disappointing, particularly since the proven assay value of the formation being'dredged has not been realized in the processed material. It has been found that this is due to a loss of values occurring in the region generally adjacent to the suction head, which probably results from a dropping out of the heavier gold or mineral values from the mineral moving toward the suction head.

In general it is an object of the present invention to provide an improved dredge construction and method which will make use of hydraulic suction, but which will avoid the defects and difficulties outlined above.

Another object of the invention is to provide a dredge construction and method of the above character which will be relatively inexpensive compared to dredges of the bucket line type, and which therefore can be used in many instances where more elaborate equipment would be prohibitive.

Another object of the invention is to provide equipment of such a character that it may be land borne for test or exploratory operations.

Another object of the inventionis to provide a dredge construction and method of the suction type in which a classifying action takes place in conjunction with movement of material to the suction head.

Another object of the invention is to provide an equipment and method capable of coping with flash flood conlarge rocks found in the formation are placed back into previously worked areas without lifting the same from the water.

Another object of the invention is to provide a suction dredge in which a classifying action takes place without clogging of the suction head.

A further object of the invention is to provide a we tion dredge and method in which the pumping means is mounted in such a manner with respect to the suction head, as to produce a relatively powerful suction with a minimum amount of power consumption.

lAdditional objects and features of the invention will appear from the following description in which the preferred embodiment of the invention has been set forth in detail in conjunction mm the accompanying drawing.

Referring to the drawing:

Figure 1 schematically illustrates dredging apparatus incorporating the present invention.

Figure 2 is an enlarged detail in section illustrating the bucket and suction head.

Figure 3 is a cross-sectional view taken along the line 3--3 of Figures 1 and 2.

i In accordance with the present invention digging means of the bucket or dipper type is employed for operating upon a bank or other underwater formation. A special suction head is disposed directly within the bucket and is connected to pumping means for creating the requisite hydraulic suction. When in operation material within the bucketis classified as to size with the smaller sized material carrying the desired mineral values passing into the head and being discharged upon the barge, and the relatively large boulders and rock remaining in the bucket. Accumulated boulders or rock are from time to time discharged in previously worked underwater areas where they will not interfere with continued operations.

Referring to the particular construction illustrated in the drawing, I have shown a dipper or bucket 10 having a bottom 11 provided with a digging edge or teeth 12. The front side of the bucket, above the digging edge is open to receive material. The bucket is shown carried by the rigid structural member 13 which is generally referred to as a bucket stick. As representative of suitable means for carrying the stick 13, and for operating the same as required for the various digging and discharge operations, I have shown a boom 14 to which the stick is attached by a pivot pin 16. The boom in turn is carried by the pontoons or barge parts 17, and by means of operating cables 18, it can be raised or lowered as desired.

Additional operating cables

19 and 21 can be manipulated as by winches located on the pontoons, and serve to swing the stick for digging and return movements of the bucket.

The stick 13 also serves to mount the centrifugal pump 22, which has its discharge connected to a conduit 23 that extends above the water level for discharging material for processing. The driving means illustrated for pump 22 includes the electric motor 24 and gear box 26, which preferably are likewise mounted upon the stick. Conduit 27 connects with the inlet side of pump 22, and at its lower end is connected by journal coupling 28 with the hollow suction head 29. The suction head preferably consists of a Wall which may be cylindrical, and which is provided with a plurality of perforations 31. It is desirable for the lower end of the head to be journaled .to the lower wall of the bucket as indicated schematically at 32. A shaft 33 extends downwardly through conduit 27 from pump 22, and has a driving connection with the head. This shaft rotates with operation of the pump, and serves to cause cont-inuous rotation of the' head. As will be presently explained a perforated head of this type makes it possible to carry out size classification within the bucket, and at the same time continuous motion of the head prevents clogging of the perforations 31.

scribed above the head rotates continuously, it will be evidentthat itrnay be oscillated or reciprocated with sufficient amplitude to, prevent clogging of'the 'per fora t-ions If desired the head maybe provided withribs or corrugation that may extend inan axialdirection', to aid in breaking conglomerate material beingpressed against terial tends Pressed against sthe'headby the Con sm 'n action of the bucket", during digging operations.

The head29 extends substantially the entire height of the space 36 within the bucket andris locatedsbetween' the open front of the bucket and the bucket back-wall; and between the side walls.

It 'islndesirable to provide theflbucket with hydraulicjettingnozzles! Thusoneiorh'lore nozzlesslfl "connect with the watersupplyfpipe 38, wandsare ,di'sposed tofdischarge/ in a direction rearwardly immtheopen, irontjof Although as de- T 4 thesame. In" this connectionit maybe notedthat'mal ing action with a minimum amount of power. m.My,-dredge is particularly applicable for use in the tropics or like regions where minimum servicing is dB-' sir ahle, and where i the equipment must withstand adverselw'eather, conditions, such as floods. In the eventof flash flood conditions, the stick can be lowered'nnfil the bucket restsqupon the bottom. The "pin 16can be re moved to allow the stick to (drop to the bottom, with only ja cable serving toattach it to the barge. This serves to relieve thebargeof-the' weight of :a considerableipartu t "of theoperating equipment, Asfurther rneasuresythe u q boom-l tycan-be disconnected and dropped totthe bottom,u-; s

the buckehyand toward the head29; As} will presently be explained' suehijets tend AEO breakup material mov ing intolthe bucket during digging operations and aid in the desired classifying action Also they aid in creating a how into the suction head. Additional jetting 5 nozzles 39 communicate through the rear jwall of the bucketand connect with the water supply pipe'411fi Jets discharging from nozzles 39 eanbe employed maid in removing rocks, boulderspandthe like iromithe' bucket; Suitable means (not shown) such'as Valvesnareemployed to selectively control operation ofithese nozzles, whereby one or the other (ie, 37 M39)" is operatedat one,

only, time. i

,7 Operation of the dredge described above as follows: i a

In Figure i it is assumed, that an underwater bank 42 containsgold or other values and is to be operatedflupons by the bucket. ly maintain suction tending tohydraulically move mate'- 7 rial into the; suction head 29 'The operatormanipulate's the bucket whereby it is swung into the bank 42 along I an rare as illustrated, whereby material is "forced. into the bucket. Within the bucket the smallersized material capable of passing'through the perforations 31; is hy- Thepump 22 is operated to continuous-i draulieally conveyed intothe head throughwthese peters i I tions. Hydraulic movement-into the headis'faeilitated' confined, region 36 of the bucket there is no opportunity uby the action of the hydraulic jets 37, and in addition v 'thesejets act'upon masses ofaggregates tobreakthernu 5;

up, thus freeing the smallersized materiaL Within the i t i for gold or like heavy minerals to separateout without being hydraulically moved into the head, Assuming that the formation contains some largerocks orboulders, whieh do notcontain values, these remain within the bucket and after one or'more sweeps against theforma-J tion, the bucket may be swung to airearpo'sition such as illustrated indebted lines," whereby rocks are dis charged in an area not being operated upon; such as an area that has'previously been worked; As illustrated by the dotted line position of the bucketpafter swinging the :buoket'to its real-most position for discharge of the g 1 :rocksyor boulders, it may be liflted'somewhat from the 7 7 formation for its return swing to clearythedeposited rocks. The discharge of the rocks or boulders can be iai-ded by jetting water from'the nozzles It will be 'evidentflirom the foregoing thatlhave pro the jets, 37. 'Allof the gold or other mineral values head and delivered to the top of the-barge, 'and does not have an opportunity to settle out or otherwise he J come lost, The mineral bearing material is delivered 'to the top of the barge, and ll i l ll filil d boulders and I h h the enclosed space within the bucket. vided an apparatus and method having a number of f desirable features. With respect tothe methodem-- ployed, classification and hydraidic removal of the smaller I sized material iromfthe interior of the bucket takes place concomitantly with digging operations, and this likewise applies to breaking up the formation by the; action for generator, and retract the boom, stick and bucket. n

' fWhilemy eq uiprnentis intended primarily for installa I tion onbargesor pontons, it may be made; land borne,

in which ,event it is supported by a carrier oi the track I I 1ayingor1rubbertired wheel type. For exaniple the ,carriermay'heatrack laying or tiredtracton'in which; I i event" the tractor can be manipulated during diggingandj load discharge-operations, wherebythe bucket digs inthe q manner of a. back-hoe. 7 Washing orother hydraulic Y equipment for, recovering the desired values can be 10 cated onthentraetor, or on a separate trailerr When, i carried in this unanner the equipment can be used to: 1

advantage for test or exploratory purposes;

Injdescribingthe apparatus as illustrated inthe draw i 1-ing,;it is assumed that the bucket is movedforwardlyyagainst theaformationh However, the bucket can be-op eratedin; the mannerof' a hoe, and in such. event'when Q operating "upon abank, the bucket is engaged withqthe H upper portionof the bank and thenswung' downwardly: V with digging action to move the material into the bucket, r

Itclairn': I

;1.: In aqdredge 'eonstructiom a bucket having digging; 1 means on a lower wall, a stick serving to mountthe; bucket; a carrier; pivoted means onthe carrier for sup, porting the stick, a pump mounted upon the stick, means j m'ounted on thestick for driving thepurnp, a suction; head disposed within the space enclosed by the bucket, {said head comprising a vertically extending hollow mem her having perforations of a size suitable-for passing. desired material, said head being journalled for turning, 2 within said bucket, means for cyclically turning the head to ,prevent'cloggingo i the perforations with dredgedmaterial, nozzle; means for delivering water jets into, the

bucket andf inthe direction towardsthe suction head fromthe open front ofthe-fbucket, andsadditional nozzle means carried, by the bucket and disposed to delivery jets of water into the bucket andtowar'd thexopen front -ilthereof todischargeover-sized material. I a

4 2. Thedredgeof claim I wherein said head and said perforations .extend forsubstantially the entire-height of 3 In a dredge construction, a substantially enclosed bucket having digging means one lower wall, support,v nieansserving 'to mount'the hucket'for digging operations, suction means includingla suction conduitextending to the bucket, a suction head mountedwithinthe enfcl'os cd space of said bucket for movementsrelative'to V the bucket and to dredgedrmaterial contained'therein, [said suction headbeing in fluid communication with the suctionco nduit, said suction head being also provided with a plurality of inlet openings dimensioned to limit V and :elassifythe size of material passinginto' said 'suc-' V I tipn head and conduit, and means for cyclically moving said suction head to prevent clogging of said inlet openings.

4. In a dredge construction, a substantially enclosed bucket having digging means on a lower wall, support means serving to mount the bucket for digging operations, suction means including a suction conduit extending to the bucket, a suction head mounted within the enclosed space of said bucket and movable relative thereto, said suction head being in fluid communication with the suction conduit, said suction head being provided with a plurality of inlet openings, means for applying cyclic movement to said suction head to prevent clogging of said inlet openings, and nozzle means within the bucket for discharging jets of water towards the suction head and in the direction toward the open front of the bucket, said nozzle means serving to cause smaller par- 6 ticles to enter the suction head and larger oversized ma.- terial to be discharged from the bucket.

References Cited in the file of this patent UNITED STATES PATENTS