Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02B—HYDRAULIC ENGINEERING
  • E02B3/00—Engineering works in connection with control or use of streams, rivers, coasts, or other marine sites; Sealings or joints for engineering works in general
  • E02B3/04—Structures or apparatus for, or methods of, protecting banks, coasts, or harbours
  • E02B3/12—Revetment of banks, dams, watercourses, or the like, e.g. the sea-floor
  • E02B3/122—Flexible prefabricated covering elements, e.g. mats, strips
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L1/00—Laying or reclaiming pipes; Repairing or joining pipes on or under water
  • F16L1/12—Laying or reclaiming pipes on or under water
  • F16L1/123—Devices for the protection of pipes under water

Definitions

• the invention relates to a system for depositing sediment and/or protecting pipelines, cables and the like en the floor of a body of water.
• a ridge-formed system consisting of a plurality of mutually displaceable compenents for depositing sediment and/or protecting an installation against fishing gear, ships' anchors, and the like, is already known.
• the present invention as defined in Claim 1 presents a system which is so flexible that it can adapt to very rugged seabed contours and at the same time maintain a continuous surface to further the sediment depositing effect and to present no obstacle to fishing gear passing over the system.
• the upper surface of the flexible system according to Claim 2 has no discontinuations, even with different settlements of adjacent modules.
• the fastening according to Claim 3 presents a simple and cheap method of connecting the movable parts to the supporting parts.
• the hooked connection according to Claim 4 allows for release of the ties in case of removal of the movable parts over top of the structure.
• a perforation according to Claim 5 reduces the lifting forces on the structure.
• Flaps according to Claim 6 ensure a steady contact between structure and seabed, so that fishing gear always slides over the structure without hooking its edges.
• the system according to Claim 7 is able to absorp very great impacts frcm dropped objects.
• the unprolongable ties according to Claim 8 prevent the top of the protective cover from coming to rest on the installation to be protected.
• the construction material according to Claim 9 ensures flexibility and tight contact with the seabed.
• the method according to Claim 11 allows for immediate start of production anywhere, either near the site of installation or in the nearest harbour, and possibly for saving of transport of sand and stones from shore.
• the method according to Claim 12 gives a very high production rate per day.
• the method according to Claim 13 presents a maximum laying speed. By the method according to Claim 14 the laying of the protective cover to a certain extent is independent of weather conditions.
• the method according to Claim 15 presents a rational, cheap laying of the covers when they can be laid together with the cable or the pipeline.
• the materials according to Claim 16 allow for adjusting the duration of dissoluticn of the materials to duration of the laying procedure.
• Fig.1 is a cross-section taken along the line I-I of Fig.2,
• Fig. 2 is a plan view of a preferred embodiment of the invention.
• Fig. 3 is a longitudinal section taken along the line II-II of Fig. 1
• Fig.4 is a cross-section taken along the line IV-IV in Fig.5 of an alternative embodiment of the invention
• Fig.5 is a longitudinal section along the line III-III of Fig. 4,
• Fig. 6 is a cross-section of a catamaran type laybarge provided with jackup legs. Two different water leeel situations are shewn in the figure.
• flexibility of the protective structure is important. This may be obtained for instance by means of a short length of the modules in which the cover is sectioned, and by flexibility between the individual components of the structure, cf. Figs.1-5.
• 1 may be further divided in a supporting lower portion 1 and 2, and a loose upper portion 7 resting on either 2 or 3.
• 3 may be prevented from sliding downwards for instance by means of at least one tie connecting a point of the underside of 3 with the top of 1, for instance with the axle 5 of the hinge between the symmetrical halves of 1.
• the tie will allow for 3 to move upwards over top of 1 in case a dragging anchor hooks the edge of 3.
• the connection between the tie and 3 and/or the top of 1 may be some type of hook that releases its grasp when the tie is tightened after 3 has passed over the top of 1.
• transverse joints between adjacent modules 1, and/or between 2 and 3 may be perforated.
• the top hinge between the symmetrical halves of 1 may be designed so that the acute angle between the halves cann open up only to a certain point. A simple way of obtaining this is to place the axle 5 below the centre of the halfcircular mating parts of the hinge, of. Figs. 1 and 4.
• the construction material is concrete. Also other materials are applicable.
• 4 and possibly 3 and 2 may be formed of longitudinally extending cushions made of for example plastic cloth filled with sand or stones, possibly mixed with asphalt with permanent plasticity, so that it will always follow after, if the seabed along the edges of the structure is eroded.
• the underside of the cushions may be provided with horizontal stays.
• the invention may be used for protection of for example submarine pipelines near offshore platforms from objects falling overboard from the platforms.
• opposite symmetrical halves 1 of the structure may be interconnected by prolongable tie means 16 above (Fig.1) or below the installation 15 to be protected.
• the kinetic energy of the falling object thereby is reduced with the energy required to prolong the tie 16 when the falling object depresses the top of the cover and conse quenty spreads the sides of the cover.
• the tie may be made of elastic material, e.g. neoprene or natural rubber, or of plastic, e.g. nylon, aluminium, steel or other material. Lowering of the top of 1 to the level of the top of 15 may be prevented by an excessive strength of 16 or by means of additional ties with higher strength than that of 16.
• the covers may be fabricated on shore and transported to the installation site on a surface vessel. Or the fabrication may take place onboard a mothership. If the construction material for instance is concrete or sediment filled cushions, the sand and stones involved may possibly be taken from the sea bottom in the near of the site of installation.
• Concrete modules preferably are fabricated by a machine that puts the concrete under pressure and vibration at the same time, whereby the production rate per day can be increased very considerably.
• Small uncomplicated elements to protect for instance a cable or pipeline of minor diameter may be laid at the same time as the cable or pipeline is laid. If cables are laid pairwise, the elements may have two parallel longitudinally extending notches for the cables on their undersides and be placed on top of the cables during the laying operation.
• the elements may be attached to the cables by means of ties that become dissolved by the water shortly after the laying, so that the elements get freed from the cables.
• the ties may for example be made of polyvimylalcohol coated with a layer of cellulose the thickness of which is adjusted to the time it takes to lay the cables.
• the elements may also be placed on a single cable to be laid, if cable and elements are hanging from an auxiliary wire that is wound off from the laybarge in the same way as the cable is laid.
• the attachment of the cable and elements to the auxiliary wire may be performed by the same kind of dissolvable tie as described above.
• Larger covers may be laid in deeper water by means of an unmanned, remotely controlled submersible. Normally a mothership at the site of installation is required for attaching the covers to the submersible.
• the mothership is supplied with a crane capable of lifting the submersible up to the deck through a moonpool, or outboard the stern, and afterwards l ⁇ wering the submersible with the attached covers into the water.
• the mothership may have an opening under water through which the submersible can pass.
• the mounting of the covers to the submersible in this case may be performed by divers under water, or take place in a hold of the ship that can be made dry during the mounting of the covers.
• the covers may be laid for instance by means of a special catamaran type barge as shown in Fig.6.
• the symmetrical halves 8 of the barge are interconnected by portal frames 11 on which cranes 10 can move transversely and longitudinally, and by means of a frame 14 lift a row of modules 12 from the supply barge 13 and lower them to rest over the pipeline 15 on the bottom, when the supply barge 13 has been removed.
• the laybarge is supplied with jack-up legs 9. During the laying of each row of modules, the barge is raised above the water surface to minimize the influence of the waves.
• the legs 9 are jacked up, the barge is moved one length forward, is raised above water surface, etc.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Environmental & Geological Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Laying Of Electric Cables Or Lines Outside (AREA)

Applications Claiming Priority (8)

Publications (1)

Family

ID=27448643

Family Applications (1)

Country Status (2)

Families Citing this family (9)

Family Cites Families (4)

• 1978
  • 1978-08-23 WO PCT/GB1978/000010 patent/WO1979000108A1/en not_active Ceased
• 1979
  • 1979-03-14 EP EP19780900091 patent/EP0020321A1/de not_active Withdrawn

Non-Patent Citations (1)

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