US2659211A

US2659211A - Marine excavator

Info

Publication number: US2659211A
Application number: US41164A
Authority: US
Inventors: Notarbartolo Pietro; Poledrelli Carlo
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-07-28
Filing date: 1948-07-28
Publication date: 1953-11-17
Anticipated expiration: 1970-11-17

Description

N 1953 P. NOTARBARTOLO ET AL 2, 9, 1

MARINE EXCAVATOR 3 Sheets-Sheet 1 Filed July 28, 1948 fz'ezmzizzrZarwza Q/Za foZedreZZ,

7, 1953 P. NOTARBARTOLO ET AL 2,659,211

MARINE EXCAVATOR 3 Sheets-Sheet 2 Filed July 28, 1948 Pzira/Vaiariakiah Nov. 17, 1953 P. NOTARBARTOLO ET AL 2, 5 ,2

MARINE EXCAVATOR Filed July 28. 1948 S Sheets-Sheet 5 fiz'zmjz azaridrzh' z? fbiedrell.

AT ORNEY Patented Nov. 17, 1953 MARINE EXOAVATOR Pietro Notarbartolo and Carlo Poledrelli, Rome, Italy Application July 28, 1948, Serial No. 41,164

16 Claims. (01. 61-72) This invention relates to a method and. apparatus for either interring or disinterring submarine cables including reasonably flexible piping. The

primary object of the present invention is to make it possible to bury a cable at a depth below the bottom greatly in excess of what has heretofore been believed possible and also to bury or to remove a cable where the water is quite deep.

An object of the invention is to provide a method of applying powerful water spouts from an excavator body having wide latitude of movement with respect to the cable ship or other naval craft from which the cable laying or cable removing operation is controlled.

A further object of the invention is to indicate the direction in which a cable being disinterred is directed in order that the cable ship or other vessel may follow this direction or path.

A further object of the invention is to provide an excavating device which may surround a cable being disinterred and which may move forwardly with respect to the cable either by its own weight or by means of auxiliary jets or by small motordriven friction wheels resiliently engaging the cable; or by any combination of these means, the result being that the excavating device easily follows the direction of the cable to be disinterred. A preferred form simultaneously cuts an annular path around the cable, and in addition removes the material directly above the cable facilitating its recovery.

A still further object of the invention is to provide a method of burying or disinterring a cable by means which create a basin in the sea floor, rather than a mere trench, the basin moving progressively. V

In the drawings: c

Figure 1 is a diagrammatic view illustrating a. vessel disinterring a cable at the front end and simultaneously interring a substitute cable.

Figure 2 is an elevation partly in central vertical section of a preferred form of excavator.

Figure 3 is a front elevation of the excavator, half in vertical mid-section.

Figure 4 is a slightly modified excavator shown as supported by a cable to be buried.

Figure 5 is a further modified form of excavator.

Figure 6 is one of a series of auxiliary ejectors.

Figure 7 is a horizontal section above the pivot rods of the preferred form of excavator.

' Up to the present time it has frequently happened that a cable has become so deeply embedded that it is cheaper to lay a new cable than to disinter the old one. An exception naturally exists where some fault has to be repaired or the I terminal has to be shifted slightly, and in these cases it is necessary to go to the heavy expense required under old practice. Another difficulty is that where the water depth is reasonably shallow, the draft of a suitably equipped cable ship is too greatto permit navigation at that depth and this has required the use of smaller craft, the ability of which is seriously limited. Another point of diificulty has been that where a cable was buried deeper than say a foot, the pulling on the cable itself to free it frequently exceeded the limit of elasticity of the protective armor of the cable and it would break.

The present invention is based on the thought that a cable can be laid at almost any reasonable depth with much convenience and even for a distance of several miles from the shore, if we employ powerful streams of water applied from nozzles in an excavator that is not rigidly connected with the vessel and hence can precede the vessel and enter shallow waters below the draft of the mother ship.

The present device can readily lay a cable two feet beneath the bottom and this is generally considered a sufficient distance to insure against possible mishaps caused by tide or by mechanical actions. The water jet method here illustrated is capable of burying a cable two or three times that depth and can as readily remove a cable buried a fathom beneath the sea floor. It can operate at pressure up to fifty atmospheres.

Referring particularly to Figure 1 showing the general idea, a cable ship or other vessel I0 is equipped with a pump II, a compressor I2, a cable winding device M, a towline I 6, and of course the usual devices (notshown) including dynamometer, sonic depth finder, profile recorder, cable length computer, etc. At the front end of the ship the excavator is numbered 20 and it sur rounds a cable 2| which in this case is being disinterred and wound on spool [4 as it is recovered. An air pipe 23 leads from the compressor to furnish bubbles 54 to indicate on the surface of the water the direction of the cable and to operate a small compressed air motor driving a pair of wheels 55 engaging the cable 2| to move the excavator 20 forward on the cable. One or more water pipes 22, either single or multiple, lead from the pump II to the excavator. The excavator 20 is shown as throwing a forward annular main stream 24 and an auxiliary stream 25, the former surrounding the a buried cable 2| and the latter clearing away the material above the cable.

At the rear of the ship it an excavator (it is being pulled by towline l8 and is burying a cable 3| which has previously been lightly laid on the sea floor or bottom 32. Naturally a cable can be buried as it is unwound. As. in the previous case, the jets of water from the excavator clear a basin for the cable and the natural action of the sea buries the cable at the depth to which it is pulled. down by the weight of the excavator 3t and its applied ballast. The depth at which. the cable 3| will be buried will also dependupcn.

the tautness of the towline l8 and its length;

In Figure 2 the excavator 25ris shownirpits preferred form. It consists mainly of three ma:

ior portions: a top portion 4| of the main .body..

a similar cooperating lower portion 42; and a readily removable secondary ejector 43,. These ing; from an cutletbox 5Lwhich is supported by the. cable. 2 i: and a, loose clamping... plate 5.1. secured by bolts- 53 so. that. the, outlet box may readily. be removed from. the: cable. The outletbox tiireceives; its water. supply, from main wate nine an eceives. infill. a nine. 23.- shown separa e ion. onv nience of illustrati n but a tually cate nsi e or. ached: to the. mai Wate p ne 2am tinny; eas s. th air. nine 23- c mpre s d air is: su n d o aus buhblesesuchz as'indicated. at to. to riseto the sur ace. tosho t e d ction-t wn the. cabl extends. and the. air: also. drives, asrnall. com; pressed air motor within thecutlet box, and dniving 'the friction or traction wheels idon; opilov e-side of t e cabl When. the: ra tio wheelsii are used,.the=outlet.b.ox til issecured to the main; p rtion. cub -exca ator. by" a ri i rod: 1 b whe e th se. wheels are. omitted: or. are. driven, from the. excavator. body, aszis. generally the caselhe. rodisireplaced by a: simple wire. which. under tension pulls, the outlet box along behind the excavator; as it, ad-. vancea along, the-cable.- 2i. gravity. by auxil ary c r jets 4am; nth wheasyie dinalv en: gag-ingthe. cable:v Within. the outlet box. is} t valve/independently. contrcllingtheflow oj;water th pipeflit This-valve. is. indicated by lever 5,8, whichcan-manually be controlled by, thediver whoeene a yompan s the expediti n,- or. in our. later. models this valve. is electrically OQIL- trollediromthe ship. .any. well. known, fashion.

As. best. seen in Figure 3,. attire, left the upper sectiondlandthe lowensection rilareieach com: n e n th mselves. having, alar e. cl ar. cyline dr el. ten nait and hinge. on. each ther. by e th r qi' vzq i t rode i t er or bo of which canreadily beireniovedi from the lugs 5'1 and 52, one; pair on theuppenporticnand the other-pair onthe lower portion. Ingt-hisway the= two portions are heid together forming a hollow frusto-conical body. The inner wall 63 onea'chi portion is: cylindrical. while the outer.

waliiBk-is conical; While; the water enters: the top section: thru pipe- 543M181 the; bottom section thru pipetfi, it, emerges as an annnlanjet or stream 24; as, thQYWfi-llfil passes thru; the arcuate, slits $5; of. practically? 1808 each. A; ballast. preferably oi, lead; surrounds; an, angle 0t 60}? or. thebottom of, the excayator and, additional weights suclras. 611111216; be, applied, depending. of course upon. the, depth which the cablelies am ne p d of. r v ofthe excavator.

As the pull of the" winding device M; keeps the cable 2! from assuming a catenary form, the inclination of the cable is such as to cause the vertical component of the weight of the ballasted body to be sumciently great as to counterbalance the reaction of the annular jet, hence the excavator will, in absence of either traction wheels or reverse jets, advance along the cable in accordance with the amount of ballast and the inclination; of; the cablemodified'by the speed of the mother ship. It will-be noted that, differing from all previous devices, the advance of the excavator is generally quite independent of the. advance of the ship. With the traction wheels 55 in use the excavator 28 may move intothfillow. water while the cable ship remains indeep water.

The. auxiliary ejector or nozzle G3, fed thru pipelifi, fits in apierced lug 88 rising from the upper portion l! near the annular nozzle 65 and may consist of a mere conical pipe such ashli3. having a, vertical slot. ll preferably broken into. a number of portions bysmall partition cr bridges. 12. For: sandy bottoms this type ofsecondary ejectoris. very satisfactory and four partitions dividethe. secondary nozzle, into. five lone slots, hese beinadirected upwardly andabit. forwardly. Where. the. bottom is. muddy; the type. oi; secondary ejector shown. in Figureefi is, a bit more satisfactory. The flexible pipe 79; is threaded. to. receive. a union l3: and the; type; of lector showninEisure 6 isnmerely fiaring, being of. the. samevddth as the. ejectoreii: but rising asat. lttda fanshapeand-having thesameslotsildivided bythe. partitions '52.. The Water. blade in this case i directed generally forward, and. somewhat. upwardly. Av small: boss, 1i fits into thaholein lugfiland may be secured in place by any ordinaryfastening.means- The pipe 19. permits angular adjustment of the secondary ejector. whether. arsimplepipc like, 123. or the fan shape showninFigurefi, or any of theinter-- mediate nozzles... It. isthe. work of but minutes to substitute one..- secondary. ejector for another, here being, anurnber of them, in arset.

InFigure. 4 a. somewhat. modified. ejector; is illustrated, this. form being particularly suited tolaying. a cable... The. cable 3i as shown: has already. been laid upon thebottom and; the-excavat'or .30. supportedby this... cable, inv fact resting directly. upon, it, the, support being: by a carriageaflfl, inwhieh are pivoted three or more wheels 8| of a shape to fit. the'cable 3!. The

excavator, has. a. bracket, 82- turning' freely on the. central .pivot,84. and a shackle=85 of generally U -shal1e turns, freely. about. the same pivot 8d. The, towline, l6 preferably endsin a chain 85 to give added weight and we freely surround the chain at times with a steel; pipe- 81 to act as. a-further. ballast. The forward nozzles, are numbered 88; and-t d wnwardlydirected: nOZr zles are; numb red.- Bfl. pr ferablyone' row or ozzl 89. bein oneach; side. and therebeing but asingle vertical; row out: nozzles 88%., The

maller. ho s-.- 90. ar preferably directed meaft and aid materially in clearing theimaterial while. dieginethe trench. Inthis: case the weight: of the excavator 3.0,with-or without addedballast pulls, the. cable; 31: down to, the desired" depth. In this particular modification a water-pipe. 9.1" leading, on one. side controls, the front: nozzles 8. nda similar pipe. on the-opposite side: controls the nozzles, an on eaehsidel aswell as the flow thruthe smaller holes 90., The: velocity of iiow is controlled by the speedof therpumps :feedmg the dual. line 22a enclosing. thepipeslil.

' There are times when the depth at which it is desired that the cable shall be buried or the sea depth is so great that the interference 9;. several pipes makes it advisable to substitute a self-contained unit. The modified form of excavator shown in Figure receives electrical current thru the towline [6 connected to the shackle 85 pivoted to the carriage 80 as before. In this particular modification the water jets are all supplied by an electric pump 95 having an intake 96 and discharging thru a pipe 91, successively to the front nozzle 98, the auxiliary nozzles 99, the bottom nozzles I00, and the exit end of the pipe. In this modification the pump constantly discharges water which flows rearwardly as indicated at l0l which aids in moving the excavator forward. The amount of water delivered to the front nozzles 99, or to the intermediate nozzles 99, or to the bottom nozzle I90 is controlled by valves I03 and I04 electrically operated thru current wires within the armored cable I05, leading from the towline It to the excavator body which in this case is quite heavily armored as indicated at I06 to'give very considerable weight and also to withstand the great pressures to which this'particular modification will be subjected.

Neither of the two valves are ever closed completely but the amount of closure determines the relative amount of water discharged thru the front nozzle or the other nozzles, there always being some discharge at I01. As in the other modification, the idler wheel I98 merely prevents the carriage 80 from leaving the cable 3| on which it is supported. As perfectly obvious-this device will inter a pipe just as well as a cable where the pipe has the necessary amount of bending which can be rather slight when the towline I6 is of considerable length. The pump 95 is of variable speed type, draws in the sea ring either a cable being payed out or a cable previously laid on the sea floor. The main nozzle 98 consequently may be directed slightly upward as shown or at a steep inclination to direct its stream across the cable.

What we claim is:

l. The method of recovering a buried submarine cable or pipe which consists in progressively discharging a substantially annular water jet roughly coaxial with the buried cable, raising the free end of the cable, and simultaneously discharging a water jet upwardly and forwardly with respect to the axis of the annular jet so as to remove the overhanging materials of the sea floor above the buried cable.

2. The method of laying a cable or pipe below 3. The method of claim 2 in which the basin is cut by means of jets of water at high velocity, certain of said jets being directed vertically downward below the cable in the basin to insure the formation of a basin at least deeper 6 below the sea fioor than the desired depth of the cable, other jets located below the cable in the basin being directed forwardly whereby to form a constantly moving basin and prevent the formation of a-tunnel.

4. The method of claim 2 in which the basin is cut by means of an annular water jet substantially coaxial of the payed out cable and surrounding the cable in the basin.

5. The method of claim 2 in which the cutting of the basin is by means of a series of jets of water at high pressure and at different angles with respect'to horizontal and vertical and varying the velocity of the water thru the series of jets independently of each other, so as to dig the basin deeper or shallower as may be desired.

6. In a ship controlled submarine excavator, for burying or excavating a cable, a body supported at least in part by the cable, means for discharging a stream of high velocity water thru the body adjacent the cable to cut a basin, and means for moving the body forwardly along the cable independently of the movement of the ship.

7. The device of claim 6 in which the body is suspended from a carriage movable upon the cable.

8. The device of claim 6 in which the means include motor driven members which engage the cable to propel the body along th cable.

9. In a device for burying a cable beneath the sea floor, a ship, a cable extending from the ship to the floor, a carriage resting upon the cable, a body suspended from the carriage, a towline secured to the ship and pulling the carriage along the cable, a motor-driven pump within the body drawing water from the sea and discharging the water thru a system including a water conduit having an exit end at the rear of said body to aid in advancing the body, a forward nozzle at the front of said body for cutting a basin in the sea floor in advanc of the body and below the cable, an auxiliary nozzle directed downwardly to deepen the basin, a valve between the two nozzles, and a second valve between the auxiliary nozzle and the exit end, said valves controlling the relative amounts of water discharged thru the two nozzles and thru the exit end whereby to make the basin deeper or shallower and thus determine the depth at which the cable will be buried as the natural action of the sea replaces the sea floor as the basin moves in thedirection of the yet-unburied cable.

10. A device for disinterring a cable or pipe buried beneath a sea floor, comprising a shell having a forward annular nozzle surrounding the cable being freed, and means for conveying water under pressure to the shell and thru the nozzle, in which the shell is formed by two generally similar sections together forming a truncated cone, each section discharging thru an arc of approximately one section above the cable, and the means includes a pipe for each section whereby the discharge of water may be from the upper section alone, the lower section alone, or from both sections together.

11. A device for disinterring a cable or pipe buried beneath a sea floor, comprising a shell formed of two generally similar sections together forming a truncatedcone, each section with a forward opening to form half of an annular nozzle, a high pressure water pipe for each of the two sections, an auxiliary nozzle and a third pipe leading to said auxiliary nozzle, said auxiliary nozzle throwing a jet or blade of water forwardly 1 ancht-imvandiyto:removeeverheneingimaterialiM theasearfioerr 12." The device ofclaim; 10 with meansnflxed with respect to the shell for moving the shell away from the freed portionni-the pipe-or-cable and nward: the; stihaiburied hortion;

l3; 'I-'he device of claim; 121m which thee-hell advancing means yieldinglyl engages; the cable; or pipe and is motor driven:

15 The device of claim 11 with. rollers. at a fixed-distance from the shell yieldingly engaging the cable-or pipe, and means to drive the rollers whereby the shell andtheth-reje pipesmay bead. vameed: along; th cable-nor pipe, independently of mevementof a; mother vessel taking in the cable or pipe asilnis' disin cd;

115 A. submarine excavator comprising a, body, a va riahle speed pump withinthe body,:an intake for leading seawater to the pump, a conduit; fed by the pumpdischarging to the-sea in rear of the excavator, nozzles discharging forwardly and downwardly from the conduit through the lower nortiqrr of; the body, ereversiible nozzl'ezvat the fprwa rd-end-ci the conduit; and means for altering the-: relative a-mcunts of water discharged by the rear, 'front and intermediate nozzles toexca vajoe a; shallower or deeper bain beneath the ea 11.

15;. An excavq ter for burying azsixbmarfine 'aible orderdisinterring a; buriedscable, controlled from 3;; mother vessel butv operating independently thereof; comprising "a: body supportedgeit lea-stain part by theacable, means for movingrtheihody on the ca-ble independently of the movement of the mother vessel; aplurality of. water'jets extendeing fromthe b0dy,- cnecjet discharging: above; the centerline of e the body andamother jet: digch'arg: hag-below; such centerline, a pump fon discharging water at high, pressure through: the jets; means;- for altering at: will. the relative amount; of water passing through-the 181351130 cutzthei searfloor at a greatercra less angletcuformearbasin' ordesired depth, a'nde thirdnjetdischarging water in rear of the; body to" aid: immovlng. the body' for-' ward to advance it on the cable;

PI'ETRO NDTARBARTOLOZ CARLO POIJEDRELIL II.

re ce C e n e e t this; inherit FOREIGN PATENTS? Number I Cb'un Dane. .5, 5 q rm l iy W" 31332 70.51430; Ge many -t---.---'-.---- or 1941