EP0112877B1 - Machine de creusement de tranchees sous-marines - Google Patents

Machine de creusement de tranchees sous-marines Download PDF

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Publication number
EP0112877B1
EP0112877B1 EP19830902110 EP83902110A EP0112877B1 EP 0112877 B1 EP0112877 B1 EP 0112877B1 EP 19830902110 EP19830902110 EP 19830902110 EP 83902110 A EP83902110 A EP 83902110A EP 0112877 B1 EP0112877 B1 EP 0112877B1
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EP
European Patent Office
Prior art keywords
sled
pipeline
trench
along
discharge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19830902110
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German (de)
English (en)
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EP0112877A1 (fr
Inventor
Daniel Kai Carstens
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CARSTENS, DANIEL KAI
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Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0112877A1 publication Critical patent/EP0112877A1/fr
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Publication of EP0112877B1 publication Critical patent/EP0112877B1/fr
Expired legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F5/00—Dredgers or soil-shifting machines for special purposes
    • E02F5/02—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches
    • E02F5/10—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables
    • E02F5/104—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water
    • E02F5/108—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water using suction-effect devices
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F5/00—Dredgers or soil-shifting machines for special purposes
    • E02F5/02—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches
    • E02F5/10—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables
    • E02F5/104—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water
    • E02F5/105—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water self-propulsed units moving on the underwater bottom
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F5/00—Dredgers or soil-shifting machines for special purposes
    • E02F5/02—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches
    • E02F5/10—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables
    • E02F5/104—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water
    • E02F5/107—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water using blowing-effect devices, e.g. jets
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/02—Travelling-gear, e.g. associated with slewing gears
    • E02F9/026—Travelling-gear, e.g. associated with slewing gears for moving on the underwater bottom

Definitions

  • This invention relates to an underwater trenching machine which will cut a trench under a pipeline and also remove the spoil from the trench to allow the pipeline to fall into the trench under its own weight.
  • Some underwater trenching machines comprise a sled which is tethered by a cable to a barge which, as it moves forwards on the surface of the sea, pulls the sled along the seabed.
  • US-A-4114390 describes one such machine in which the sled is saddle-shaped frame and is supported on the pipeline by transverse rollers, the frame comprising tubes through which water is fed under pressure to fluidizing nozzles so that the non-cohesive bottom of the seabed is fluidized and the pipeline sinks into the fluidized bottom material as the sled is pulled along the pipeline by a cable connected to a winch on the barge.
  • tractor type machines having hydraulic or electric drive, which are propelled by wheels or endless tracks in engagement with the pipeline itself (e.g. US-A-4087981) or the seabed.
  • a problem is to get enough friction between the wheels and the pipe without damaging the latter or its anti-corrosive coating, or, where the tractor drives on the seabed, for the soil to be firm enough to prevent the track sinking into the mud.
  • Another known machine described in US-A-3576111, comprises a sled which uses high pressure water jets aimed in the direction opposite to that in which the sled is to move. These jets propel the sled forward.
  • Some jets are aimed forward to cut the trench and others generally upwards to help push the spoil out of the trench, which is assisted by discharging air at the bottom of the sled.
  • the main disadvantage of this system is that in order to get a net forward thrust on the sled more water must be discharged to the rear of the sled than to the front. Also a separate air lift system is required for spoil removal. The efficiency of this type of machine is very low, and decreases with depth of operation.
  • GB-A-1479459 describes an underwater trenching machine for dredging trenches on the seabed for receiving pipes or cables comprising a sled which is towed from a supply boat by means of a tow wire attached to the sled.
  • Two pairs of downwardly directed water jet nozzles are mounted one behind the other at the forward end of the sled to loosen the material of the seabed which is then sucked up by two ejector pumps each having a suction inlet pipe of which the bottom ends are disposed aft of the water jet nozzles and below metal strips along the underside of the sled and forming a skid or runner.
  • Each suction inlet pipe which is inclined upwardly and rearwardly from its inlet end, is attached at its aft end to an angled ejector portion the aft end of which is secured to an upwardly, rearwardly and outwardly directed straight diffuser having an internal diameter increasing uniformly to the discharge aperture of the pump.
  • Jet pipes aligned with the central longitudinal axis of the respective diffusers extend through the wall of the angled ejector portions and terminate in a nozzle which faces towards the discharge aperture of the respective diffuser. Water under pressure is supplied to the jet pipes to cause the ejector pumps to suck up the loosened seabed material and discharge it to the sides of the trench through the discharge apertures of the diffusers.
  • Buoyancy tanks are provided on the sled for adjustment of the buoyancy.
  • the pipe or cable to be laid in the trench is supported by pairs of front and rear guide rollers arranged in a V-shaped formation, and is laid into the trench on leaving the rear pair of rollers.
  • the machine is such that it must be erected on the seabed. It is suggested on page 2 lines 98-103 of the description that the action of the nozzles and ejector pumps provide a reactive forward force component which can be used to propel the machine along the seabed providing the buoyancy of the machine is appropriately adjusted.
  • a pipeline of 60 cms diameter filled with water during laying can weigh several tons) in addition to the weight of the machine, and such a lifting force would increase the friction between the pipeline or cable and the pairs of supporting rollers, with an abortive result and substantial risk of damage to the pipeline or cable.
  • the frictional resistance between the skids and the seabed can only be alleviated by the lifting force imparted by the tow line to drag the skids out of and along the soil of the seabed.
  • US-A-4087981 (upon the disclosure of which the preamble of claim 1 is based) describes a buoyant self-propelled underwater trenching machine for a pipeline or cable to be laid in the seabed, comprising a sled having means for supporting it on and guiding it for movement along the pipeline or the like and comprising two side members spaced apart on opposite sides of the pipeline or the like by interconnecting transverse members including freely rotatable transverse rollers adjacent the top of the sled whereby the sled forms a kind of saddle which straddles the pipeline or the like, supported thereon by said transverse rollers and maintained in a generally upright position on the pipeline or the like by buoyancy tanks on the sled.
  • each side member comprises an upright tube equipped with a plurality of vertically arranged nozzles disposed for directing water jets at the face of the trench for breaking up soil in the forward path of the sled.
  • Each side member carries an eductor tube having its inlet adjacent the bottom of the sled and its discharge section above the top of the trench and aimed in a sideways outwards and mainly rearward direction of the sled whereby to draw up portions of the spoil broken up by said nozzles and to discharge these portions symmetrically to opposite sides of the sled.
  • the upper end of the eductor tube is provided with a venturi composed of a venturi housing in which is positioned a high pressure water nozzle.
  • the nozzle is directed towards an opening in the opposing wall of the venturi housing which is of smaller diameter than the eductor inlet to the housing and which connects with a divergent discharge tube which directs the spoil to the side of the trench.
  • Propulsion of the machine is positively derived along the pipeline by drive rollers in frictional engagement with opposite sides of the pipeline, at least one drive roller being driven by means of an electric or hydraulic motor and suitable reduction gearing.
  • Forward guide rollers which engage the sides of the pipeline in advance of the water jet nozzles at the front of each side member sense the pipeline direction and produce a torque to guide the machine on to the centerline of the pipeline.
  • the jets from the forward nozzles must be sufficiently powerful to cut away at least the upper part of the face of the trench prior to the advance of the forward guide rollers.
  • the positive driving engagement of the drive rollers with the pipeline prevents any thrust from the eductor discharges from propelling the sled forwards.
  • the sole propulsion of the machine is derived from the drive rollers. No propulsion is provided by the eductors.
  • the reduced size of the outlet from the venturi housing to the discharge section is liable to become clogged by larger pieces of spoil entering the housing through the eductor inlet, and since the discharge from the eductors takes place at a height above the top of the trench (on which the pipeline initially rests) which is approximately equal to the depth of the trench being dug, any imbalance between the sideways thrusts produced by the eductors tends to tilt the machine about the axis of the pipeline.
  • an object of this invention is to provide an underwater trenching machine and method which overcomes the above disadvantages, in which the machine is propelled solely by the means used for soil removal from the trench.
  • the invention consists in a self-propelled underwater trenching machine for a pipeline or the like to be laid, comprising a sled having means for supporting it on and guiding it for movement along the pipeline or the like and comprising two side members spaced apart on opposite sides of the pipeline or the like by interconnecting transverse members including freely rotatable transverse rollers adjacent the top of the sled whereby the sled forms a kind of saddle which straddles the pipeline or the like, supported thereon by said transverse rollers and maintained in a generally upright position on the pipeline or the like by buoyancy tanks on the sled, the front of each side member comprising a plurality of front water jets directed at the face of the trench for breaking up soil in the forward path of the sled, and each said side member carrying an educator tube comprising an upwardly extending section having an in
  • the high pressure pump jets produce suction in the eductors that lifts the mud out of the trench being cut and discharges it to the sides and rear of the trench, the water jet and spoil discharge producing a reaction on the sled in the forward direction which is used to propel the sled forwards.
  • the invention also consists in the method of underwater trenching which consists in propelling a sled along a pipeline or the like to be laid in the trench, breaking up soil in the forward path of the sled, and removing spoil from the trench as the sled advances by a pair of eductor tubes and associated water jets which produce suction at the inlets of the eductor tubes adjacent the bottom of the trench and discharge the spoil rearwardly at opposite sides of the trench respectively, characterised by using said water jets to provide a common source of power both for spoil removal and propulsion of the sled along the pipeline or the like, the forward thrust produced by the discharge of the water-spoil mixture providing the sole means for propelling the sled forwards on freely rotatable rollers mounted on the sled and resting on the pipeline.
  • the sled 1 comprises a frame formed of two loops of pipe 2,2' spaced apart in parallel upright planes by interconnecting pipes 3 to form a kind of saddle which straddles a pipeline 4 to be laid in a trench 5 cut by the sled.
  • the sled rests on the pipeline 4 by transverse rollers 6, 7, faced with rubber or other resilient material, mounted between the pairs of front and rear vertical runs of the two pipe loops respectively.
  • the sled is further transversely guided on the pipeline 4 by pairs of rollers 8, 8', 9, 9', also resiliently faced, mounted for rotation about vertical axes at the front and rear of the sled respectively on the pipe loops at opposite sides of the pipeline 4.
  • the sled also comprises two eductor tubes 10, 10' carried from the respective pipe loops 2 and 2'.
  • Each inlet connects with a vertical section 12 which leads to an elbow 13 connecting with a horizontal discharge section 14, 14' which is directed outwardly sideways and mainly rearwardly of the sled, the discharge sections 14, 14' extending symmetrically to opposite sides of the sled.
  • a nozzle 15 aimed along the respective discharge section. Water is fed to the nozzles 15 by feed pipes 16, 16' which may be interconnected so that only a single hose connection 17 is required.
  • a venturi pipe reducer 24 for example from 30 cms diameter to 25 cms diameter, corresponding to the diameters of the tube sections 12 and 14 respectively.
  • Each front vertical run of a pipe loop 2, 2' is provided with nozzles 18 to provide small jets of water aimed at the front of the trench 5. These break up the soil in front of the trenching machine. Further nozzles 19 may be provided along the bottom run of each pipe loop. High pressure water from a pump unit on a barge is supplied to the pipe loops through a hose connection 20 at the top rear end or front end of one of the pipe loops.
  • the soil loosened by the nozzles 18, 19 is removed from the trench through the eductor tubes.
  • the high pressure water streams of the water jet pumps aimed rearwardly along the discharge sections 14, 14', create suction in the eductors which lifts the spoil out of the trench 5 via their inlet ends 11 and discharges it to the side and rear of the sled through the discharge sections 14,14'.
  • the reaction of the water jet pump and the spoil propels the sled forwards and keeps it in contact with the trench face, being guided along the pipeline 4.
  • buoyancy tanks 21 At the top of the pipe loops. They also provide an uprighting force to keep the sled upright as it rides along the pipeline 4. Transverse rubber faced rollers 22, 23 may also be fitted to the machine, after it has been positioned on the pipeline, to prevent it from lifting.
  • Each tank 21 is provided with a valve in its upper part to allow air to escape, and an open pipe 21' to allow a diver to fill the tank with air after the sled is positioned on the pipeline 4 and the rollers 22, 23 locked under the pipeline.
  • the pipes 21' being open prevent the buoyancy tanks from becoming pressurised vessels.
  • the machine according to the invention has the advantage that the same power that is used for soil removal is also used for propulsion, only one power source being necessary.
  • the spoil removal pressure source does not have to be as high as that needed to cut the trench. This lowers the cost of the pumps required on the barge. Further, the water jet pump efficiency does not decrease noticeably, if at all, with increasing depth of operation. The spoil is also discharged well to the side of the trench being cut.
  • the machine may be equipped with more than one pair of eductors. If desired the spoil removal, propulsion and jetting water can be supplied through a common hose from a single pump source.
  • the hose or hoses may be connected to the front end of one or both of the pipe loops.
  • the soil at the face of the trench may be broken up by a mechanical cutter, or, by a combination of mechanical cutting means and water jets, the loosened soil being removed by the eductors and discharged outwardly and rearwardly to propel the machine forwardly and against the face of the trench being cut.
  • the rollers may be moved into or out of their operative positions by hydraulic or other power means.
  • the machine may also be used for laying cables.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Sewage (AREA)
  • Electric Cable Installation (AREA)
  • Confectionery (AREA)

Abstract

Machine de creusement de tranchées sous-marines pour des pipelines, dans laquelle un traîneau (1), comprenant deux boucles de conduite (2) disposées dans des plans verticaux sur les côtés opposés du pipeline (4) et reliées par des conduites transversales (3), est maintenu et guidé de manière à pouvoir se déplacer le long du pipeline par des rouleaux revêtus de caoutchouc (6, 7, 8, 9). De l'eau à haute pression est envoyée aux boucles au travers du raccord (20). Des ajutages (18) dans la partie verticale antérieure des boucles (2) désagrègent le sol sur le front de la tranchée (5). Des ajutages (15) de pompes à jet d'eau aspirent la terre du fond de la tranchée au travers des orifices d'admission orientés vers l'avant (11), à proximité du fond du traîneau, de deux tuyaux d'extraction (10) portés par les boucles (2) sur les côtés opposés du pipeline, et la déchargent au travers d'orifices de sortie de décharge (14) dirigés respectivement latéralement vers l'extérieur et principalement vers l'arrière du traîneau. La décharge d'eau et de terre produit une réaction qui propulse le traîneau vers l'avant.

Claims (9)

1. Machine autopropulsée pour le creusement de tranchées sous marines pour un oléoduc ou similaire à poser, comprenant un chariot (1) muni de moyens pour son support et son guidage pour un déplacement le long de l'oléoduc ou similaire et comportant deux éléments latéraux (2, 2') espacés et disposé des deux côtés opposés de l'oléoduc ou similaire à l'aide d'éléments de liaison transversaux (3) comportant des rouleaux transversaux montés foux (6, 7, 8, 8', 9, 9') situés au voisinage de l'extrémité supérieure du chariot de sorte que le chariot forme une selle s'étendant sur l'oléoduc ou similaire et supporté sur ce dernier par lesdits rouleaux transversaux et maintenu dans une position sensiblement verticale sur l'oléoduc ou similaire au moyen de réservoirs de flottaison (21) prévus sur le chariot, l'extrémité avant de chaque élément latéral comprenant une série de jets d'eau (18) dirigés vers l'extrémité frontale de la tranchée pour arracher le sol pendant l'avance du chariot et chaque élément latéral comprenant un tube d'évacuation (10, 10') muni d'une section verticale (12) comprenant au voisinage de l'extrémité inférieure du chariot, un orifice d'admission (11) et qui est relié par son extrémité supérieure à une section d'évacuation (14, 14') orientée latéralement vers l'extérieur et essentiellement vers l'arrière du chariot au-dessus du bord supérieur de la tranchée (5) et suivant l'axe de laquelle est dirigé un jet d'eau produit par une buse (15) pour aspirer une partie des déblais arrachés par les jets d'eau frontaux et pour décharger cette partie vers les deux côtés opposés du chariot, caractérisé en ce que la section verticale s'étendant vers le haut (12) de chaque conduit (10,10') conduit à un coude (13) assurant un transfert continu vers sa section d'évacuation respective (14, 14') qui est située directement au-dessus de l'extrémité supérieure de la tranchée et s'étend dans un plan sensiblement horizontal et présente un diamètre sensiblement constant sur toute sa longueur, les buses de projection d'eau respectives (15) étant disposées au niveau des coudes respectifs et orientées le long des sections d'évacuation correspondantes, à travers lesquelles les mélanges eau - déblais sont déchargés pour former les moyens uniques pour propulser le chariot le long de de l'oléoduc ou similaire.
2. Machine suivant la revendication 1, caractérisé en ce qu'elle comporte des rouleaux de guidage (8, 8', 9, 9') montés foux sur des arbres verticaux aux extrémités avant et arrière du chariot et des deux côtés opposés de l'oléoduc ou similaire, les rouleaux de guidage avant étant montés à l'arrière des jets d'eau frontaux (18).
3. Machine suivant l'une quelconque des revendications 1 ou 2, caractérisée en ce que chaque cadre latéral (2, 2') comporte de plus une série de jets d'eau (19) disposés le long de l'extrémité inférieure de chaque élément latéral et dirigés sur le fond de la tranchée.
4. Machine suivant l'une quelconque des revendications 1 ou 2, caractérisée en ce que chaque élément latéral (2, 2') comporte deux boucles de tubes disposées dans deux plans verticaux parallèles et espacées à l'aide de tubes de liaison (3) pour entourer l'oléoduc ou similaire et qui portent les rouleaux foux, transversaux (6, 7) pour supporter et guider le chariot sur et le long de l'oléoduc ou similaire, les boucles de tubes présentant au moins un orifice d'admission (20) pour leur liaison à une source d'eau sous pression, les branches frontales des boucles étant munies de buses (18) produisant des jets d'eau dirigés sur la paroi avant de la tranchée, d'autres buses d'eau (19) étant prévues le long des branches inférieures des boucles de tubes.
5. Machine suivant la revendication 4, caractérisée en ce que le chariot comporte des réservoirs de flottaison (21) prévus sur la partie supérieure des boucles de tubes (2, 2'), chaque réservoir comportant, dans sa partie supérieure, une soupape pour l'évacuation de l'air et dans sa partie inférieure, un tube ouvert (21') pour le chargement du réservoir avec de l'air, le chariot étant de plus muni de rouleaux (22, 23) pouvant être disposés de l'oléoduc après la mise en place du chariot sur ce dernier.
6. Machine suivant l'une quelconque des revendications précédentes, caractérisée en ce que chaque élément latéral (2, 2') porte l'une de chaque paire d'une série de paires de tubes d'alimentation (10, 10'), les tubes d'alimentation de chaque paire comprenant des sections d'évacuation (14) dirigées latéralement vers l'extérieur et essentiellement vers l'arrière des deux côtés opposés du chariot.
7. Procédé pour le creusement de tranchées sous marines consistant à propulser un chariot (1) le long d'un oléoduc (4) ou similaire, à poser dans la tranchée, à arracher le sol dans le passage de l'avancement du chariot et à retire les déblais à partir de la tranchée au fur et à mésure de l'avance du chariot à l'aide de deux tubes d'évacuation (10, 10') et de jets d'eau associés (15) qui produisent un effet d'aspiration au niveau des orifices d'admission (11) des tubes d'évacuation au voisinage du fond de la tranchée et déchargent les déblais à l'arrière des deux côtés opposés de la tranchée, caractérisé en ce qu'il consiste à utiliser des jets d'eau pour former une source d'énergie commune pour l'évacuation des déblais et pour la propulsion du chariot le long de l'oléoduc ou similaire, la poussée vers l'avant produite par le déchargement du mélange eau- déblais étant le seul moyen pour la propulsion vers l'avant du chariot sur des rouleaux (6, 7, 8, 8', 9, 9') montés foux sur le chariot et reposant sur l'oléoduc.
8. Procédé suivant la revendication 7, caractérisé en ce qu'il consiste à creuser le sol dans le passage de l'avance du chariot en dirigeant des jets d'eau sur la paroi frontale de la tranchée.
9. Procédé suivant l'une quelconque des revendications 7 ou 8, caractérisé en ce qu'il consiste à creuser le sol au-dessous du chariot à l'aide de jets d'eau disposés le long de l'extrémité inférieure du chariot.
EP19830902110 1982-06-29 1983-06-28 Machine de creusement de tranchees sous-marines Expired EP0112877B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8218816 1982-06-29
GB8218816 1982-06-29

Publications (2)

Publication Number Publication Date
EP0112877A1 EP0112877A1 (fr) 1984-07-11
EP0112877B1 true EP0112877B1 (fr) 1986-10-01

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Application Number Title Priority Date Filing Date
EP19830902110 Expired EP0112877B1 (fr) 1982-06-29 1983-06-28 Machine de creusement de tranchees sous-marines

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EP (1) EP0112877B1 (fr)
DE (1) DE3366582D1 (fr)
DK (1) DK152549C (fr)
NO (1) NO840667L (fr)
WO (1) WO1984000183A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5047083A (en) * 1989-06-15 1991-09-10 Nalco Chemical Company Process for de-oiling mill scale
US5125966A (en) * 1990-12-20 1992-06-30 Nalco Chemical Company Process for de-oiling mill sludge
NL9400605A (nl) * 1994-04-15 1995-11-01 Oord Acz B V Van Werkwijze en inrichting voor het onder water ingraven van een langwerpig voorwerp.
US9745716B1 (en) * 2015-12-21 2017-08-29 Michael W. N. Wilson Jet trenching system

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3576111A (en) * 1968-07-03 1971-04-27 Urban A Henry Jr Underwater pipeline-burying apparatus
US4087981A (en) * 1971-08-27 1978-05-09 Norman Offshore Services Inc. Buoyant self-propelled underwater trenching apparatus
GB1479459A (en) * 1974-11-05 1977-07-13 Mobell Ltd Underwater trenching machines and methods of excavating trenches on the sea bed
US4114390A (en) * 1976-06-28 1978-09-19 Shell Oil Company Burying a conduit in the bottom of a body of water

Also Published As

Publication number Publication date
DK152549C (da) 1988-08-15
WO1984000183A1 (fr) 1984-01-19
DK113084D0 (da) 1984-02-28
NO840667L (no) 1984-02-22
DK113084A (da) 1984-02-28
EP0112877A1 (fr) 1984-07-11
DE3366582D1 (en) 1986-11-06
DK152549B (da) 1988-03-14

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