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US 4,087,981 AGranted
Buoyant self-propelled underwater trenching apparatus
AssigneeNorman Offshore Services Inc.
InventorRobert M. Norman
Life of this patent
Estimating the term…
Abstract
An underwater self-propelled buoyant trenching apparatus for burying a pipeline or cable on the bottom of a body of water. Water jets on a frame cut the trench, and a venturi operated eductor means sucks up and discharges the cuttings. The apparatus is motivated by a drive roller that is resiliently urged against the pipeline. Forward guide rollers sense the pipeline direction and act to torque the apparatus onto the centerline of the pipeline. The arrangement of the jet nozzle minimize the rearward thrust. Buoyant outrigger tanks adjust the attitude of the apparatus over the pipeline. The hose bundle is buoyant due to the oversize air hose.
Claims44
An underwater trenching apparatus for burying a pipeline or the like beneath the bottom of a body of water comprising:
- a frame for positioning over the pipeline to be buried,
- jet means supported by said frame, comprising a plurality of vertically arranged nozzles for digging a trench in said bottom for burying said pipeline,
- eductor means supported by said frame for drawing up portions of said bottom cut by said jet means and discharging these portions away from said apparatus,
- a first set of rollers secured to said apparatus and contacting said pipeline to direct said apparatus along said pipeline, drive means to drive at least one of said first rollers for movement of said apparatus along said pipeline, resilient means positioned between said first rollers and said apparatus to permit movement of said first rollers toward and away from the axis of said pipeline while following variations in circumference in said pipeline,
- and including guide roller means mounted on said frame and extending in front of said jet means in contact with said pipeline to detect direction changes in said pipeline, guide roller mounting means secured at one end to said frame and having guide rollers mounted thereon at the other end for applying a torque to said frame angularly disposed to the direction of motion of said apparatus to correct the alignment of said apparatus in accordance with the direction of the pipeline whereby upon said guide roller means sensing a preselected magnitude of change in pipeline direction relative to the axis of said apparatus, a torque is applied to said apparatus to align the apparatus with said pipeline.
2 more elements
An underwater trenching apparatus for burying a pipeline or the like beneath the bottom of a body of water comprising:
- a frame for positioning over the pipeline to be buried:
- jet means supported by said frame, comprising a plurality of vertically arranged nozzles for digging a trench in said bottom for burying said pipeline,
- eductor means supported by said frame for drawing up portions of said bottom cut by said jet means and discharging these portions away from said apparatus,
- a first set of rollers secured to said apparatus and contacting said pipeline to direct said apparatus along said pipeline, drive means to drive at least one roller of said first set rollers for movement of said apparatus along said pipeline, resilient means positioned between said first rollers and said apparatus to permit movement of said first rollers toward and away from the axis of said pipeline while following variations in circumference in said pipeline,
- including at least one water hose connected to said apparatus and at least one air hose connected to said apparatus, said hoses being held together to form a bundle, said air hose being of diameter sufficient to buoy a portion of said bundle.
2 more elements
An underwater trenching apparatus for burying a pipeline or the like beneath the bottom of a body of water comprising:
- a frame for positioning over the pipeline to be buried,
- jet means supported by said frame, comprising a plurality of vertically arranged nozzles for digging a trench in said bottom for burying said pipeline,
- eductor means supported by said frame for drawing up portions of said bottom cut by said jet means and discharging these portions away from said apparatus,
- a first set of rollers secured to said apparatus and contacting said pipeline to direct said apparatus along said pipeline, drive means to drive at least one roller of said first set of rollers for movement of said apparatus along said pipeline, resilient means positioned between said first rollers and said apparatus to permit movement of said first rollers towards and away from the axis of said pipeline while following variations in circumference in said pipeline, and including said nozzles being held longitudinally arranged in vertical rows along and being held stationary relative to the axis of a vertical cutting tube and projecting therefrom in the direction of motion of said apparatus, said nozzles positioned upon one of said cutting tubes being pointed in an angular direction relative to the pipeline to offset the torque effect of a complementary nozzle positioned upon the other of said cutting tubes.
1 more element
An underwater trenching apparatus for burying a pipeline or the like beneath the bottom of a body of water comprising:
- a frame for positioning over the pipeline to be buried, jet means supported by said frame, comprising a plurality of vertically arranged nozzles for digging a trench in said bottom for burying said pipeline, a set of rollers secured to said apparatus and contacting said pipeline to direct said apparatus along said pipeline, drive means to drive at least one of said first rollers for movement of said apparatus along said pipeline, resilient means positioned between at least one of said rollers and said frame to permit movement of said roller toward and away from the axis of said pipeline while following variation in the circumference of said pipeline and including at least one waterhose connected to said apparatus, and at least one air hose connected to said apparatus, said hoses being held together to form a bundle, said air hose being of diameter sufficient to buoy a portion of said bundle.
An underwater trenching apparatus for burying a pipeline or the like beneath the bottom of a body of water comprising:
- a frame for positioning over the pipeline to be buried,
- jet means supported by said frame, comprising a plurality of vertically arranged nozzles for digging a trench in said bottom for burying said pipeline,
- eductor means supported by said frame for drawing up portions of said bottom cut by said jet means and discharging these portions away from said apparatus,
- a first set of rollers secured to said apparatus and contacting said pipeline to direct said apparatus along said pipeline, drive means to drive at least one roller of said first set of rollers for movement of said apparatus along said pipeline, resilient means positioned between said first rollers and said apparatus to permit movement of said first rollers towards and away from the axis of said pipeline while following variations in circumference in said pipeline,
- said jet nozzles being positioned on opposite sides of said pipeline and wherein substantially each nozzle is positioned at an angle relative to the center line of the pipeline in a direction to substantially offset the torque produced by a complementary nozzle on the opposite side of the center line of said pipeline.
2 more elements
An underwater trenching apparatus for burying a pipeline or the like beneath the bottom of a body of water comprising:
- a frame for positioning over the pipeline to be buried,
- jet means supported by said frame, comprising a plurality of vertically arranged nozzles for digging a trench in said bottom for burying said pipeline,
- eductor means supported by said frame for drawing up portions of said bottom cut by said jet means and discharging these portions away from said apparatus,
- a first set of rollers secured to said apparatus and contacting said pipeline to direct said apparatus along said pipeline, drive means to drive at least one roller of said first set of rollers for movement of said apparatus along said pipeline, resilient means positioned between said first rollers and said apparatus to permit movement of said first rollers towards and away from the axis of said pipeline while following variations in circumference in said pipeline,
- and including said nozzles being longitudinally arranged in vertical rows along and being held stationary relative to the axis of a vertical cutting tube and projecting therefrom in the direction of motion of said apparatus, including said guide roller mounting means being positioned below selected jet nozzles whereby said jet nozzles are able to clear a path in front of said guide rollers,
- air nozzle means carried on said frame and cooperating with said jet means to discharge air to provide a flotation effect to bottom cuttings dislodged by said jet means,
- said jet nozzles being positioned on opposite sides of said pipeline and wherein substantially each nozzle is positioned to point in a particular direction to substantially offset the torque produced by a complementary nozzle on the opposite side of the center line of said pipeline.
4 more elements
An underwater trenching apparatus for burying a pipeline or the like beneath the bottom of a body of water comprising:
- a frame for positioning over the pipeline to be buried,
- jet means supported by said frame, comprising a plurality of vertically arranged nozzles for digging a trench in said bottom for burying said pipeline,
- eductor means supported by said frame for drawing up portions of said bottom cut by said jet means and discharging these portions away from said apparatus,
- a first set of rollers secured to said apparatus and contacting said pipeline to direct said apparatus along said pipeline, drive means to drive at least one roller of said first set of rollers for movement of said apparatus along said pipeline, resilient means positioned between said first rollers and said apparatus to permit movement of said first rollers towards and away from the axis of said pipeline while following variations in circumference in said pipeline,
- and including said nozzles being longitudinally arranged in vertical rows along and being held stationary relative to the axis of a vertical cutting tube and projecting therefrom in the direction of motion of said apparatus, including independent buoyancy means supported upon said frame on each side of said pipeline, each said buoyancy means having a plurality of separate individual compartments, opening means in each compartment to provide communications with the water, and means selectively operable upon the water level of each compartment to control the buoyant effect of each compartment including a gaseous inlet means and a gaseous outlet means for each compartment whereby the fore-to-aft and port-to-starboard attitude of the apparatus is controllable.
2 more elements
An underwater trenching apparatus for burying a pipeline or the like beneath the bottom of a body of water comprising:
- a frame for positioning over the pipeline to be buried,
- jet means supported by said frame, comprising a plurality of vertically arranged nozzles for digging a trench in said bottom for burying said pipeline,
- eductor means supported by said frame for drawing up portions of said bottom cut by said jet means and discharging these portions away from said apparatus,
- a first set of rollers secured to said apparatus and contacting said pipeline to direct said apparatus along said pipeline, drive means to drive at least one roller of said first set of rollers for movement of said apparatus along said pipeline, resilient means positioned between said first rollers and said apparatus to permit movement of said first rollers towards and away from the axis of said pipeline while following variations in circumference in said pipeline,
- and including said nozzles being longitudinally arranged in vertical rows along and being held stationary relative to the axis of a vertical cutting tube and projecting therefrom in the direction of motion of said apparatus, including said jet nozzles being positioned on opposite sides of said pipeline and wherein substantially each nozzle is positioned to point at at angle relative to the center line of the pipeline in a direction to substantially offset the torque produced by a complementary nozzle on the opposite side of the center line of said pipeline.
2 more elements
Dependencies are inferred from the claim text.