Device for laying underground or digging up subsea conduits

Claim 1

A device for burying a conduit on a seabed of incoherent material and for digging up a conduit buried in a seabed of incoherent material, the device comprising: a pair of scooping units adapted for positioning on opposite sides of the conduit, wherein each unit includes a venturi tube having an intermediate portion of restricted cross section, a slurry tube within said venturi tube having an upper end at said restricted cross section of said venturi tube adapted to be positioned on one side of the conduit and adjacent the seabed, wherein said lower end is beveled in the direction of advancing movement of the device along the seabed to facilitate removal of slurry; a manifold slidably mounted about the lower end of said slurry tube having nozzles depending therefrom about said beveled lower end of and at an acute angle to said slurry tube, and telescoping means connected to said manifold for vertically moving said nozzles relative to said slurry tube and the seabed, to thereby control disaggregation; means connected to said manifold and nozzles for feeding water under pressure therethrough whereupon the jets of water from said nozzles disaggregate the seabed and form a slurry; means connected to each of said venturi tubes for feeding water under pressure therethrough wherein a negative pressure is created which causes the slurry to be withdrawn from the seabed into and through said venturi tubes; and guiding means for positioning the device on the conduit as it moves therealong for digging up and burying the conduit.

Claim 2

A device for burying a conduit on a seabed of incoherent material and for digging up a conduit buried in a seabed of incoherent material, the device comprising: a pair of scooping units adapted for positioning on opposite sides of the conduit, wherein each unit includes a venturi tube having an intermediate portion of restricted cross section, a slurry tube within said venturi tube having an upper end at said restricted cross section of said venturi tube adapted to be positioned on one side of the conduit and adjacent the seabed, wherein said lower end is beveled in the direction of advancing movement of the device along the seabed to facilitate removal of slurry; a manifold slidably mounted about the lower end of said slurry tube having nozzles depending therefrom about said beveled lower end of and at an acute angle to said slurry tube, and telescoping means connected to said manifold for vertically moving said nozzles relative to said slurry tube and the seabed, to thereby control disaggregation; means connected to said manifold and nozzles for feeding water under pressure therethrough whereupon the jets of water from said nozzles disaggregate the seabed and form a slurry; means connected to each of said venturi tubes for feeding water under pressure therethrough wherein a negative pressure is created which causes the slurry to be withdrawn from the seabed into and through said venturi tubes; and guiding means for positioning the device on the conduit as it moves therealong for digging up and burying the conduit.