SEA SLED FOR ENTRENCHING AND PIPE BURYING OPERATIONS

• US 3,877,238 A
• Filed: 11/06/1973
• Issued: 04/15/1975
• Est. Priority Date: 11/06/1973
• Status: Expired due to Term

• Current Assignee: Elmer R. Remkes, Nuke Ming Chang
• Original Assignee: Elmer R. Remkes, Nuke Ming Chang
• Inventors: Chang, Nuke Ming, Remkes, Elmer R.
• Primary Examiner(s): Shapiro, Jacob
• Application Number:
  US05/413,378
• Time in Patent Office: 525 Days
• Field of Search: 61/72.4,72.3,72.1 417/183,153 37/81,62
• US Class Current: 405/162
• CPC Class Codes: E02F 5/104 for burying conduits or cables in trenches under water floating substructures per se E02F9/06
• CPC Class Codes: E02F 5/107 using blowing-effect devices, e.g. jets digging devices using a blowing effect per se E02F3/9206
• CPC Class Codes: E02F 5/108 using suction-effect devices suction heads per se E02F3/9243, E02F3/9256
• CPC Class Codes: F16L 1/16 on the bottom

Abstract

The sea sled includes a pair of pontoons mounting depending rollers for straddling a pipeline disposed on the sea bottom. Water jets fluidize the sea bottom to form a trench in which the pipeline settles. The slurry formed by the water jets is removed from the trench by the eductor system which includes a pair of conduits each having a suction inlet at its lower end for location within the trench, a discharge at its upper end, a pair of pump nozzles each having an inlet external to the associated conduit and an outlet within the conduit directed toward the corresponding discharge, and a pair of primary nozzles respectively spaced from the inlet ends of the pump nozzles. A high pressure, low volume, fluid is pumped from the surface through the jet nozzles. The fluid emanating from the jet nozzles entrains ambient fluid and delivers low pressure, high volume, fluid through the respective pump nozzles to their corresponding discharges. The action of the pump nozzles in the conduits creates a suction whereby the slurry from the trench is pumped from the trench through the conduits and discharged to opposite sides of the trench.

Claims

1. A sea sled for use in excavating a trench below a pipeline laid along the sea bottom and for removing the slurry formed by the excavation comprising:

a base structure, means carried by said base structure for excavating the trench and including a plurality of jet nozzles directed to flow high pressure fluid below the pipeline to fluidize the sea bottom and form a slurry, means and carried by said base structure for removing the slurry including a conduit having an inlet disposed below said base structure and a discharge, a pump nozzle having an inlet external to said conduit and exposed to the ambient fluid, said pump nozzle having an outlet within said conduit for delivery of fluid to said conduit intermediate said inlet and discharge, a primary nozzle external to said conduit and spaced a predetermined distance from said pump nozzle inlet, and means for supplying fluid under pressure to said primary nozzle, said primary nozzle being disposed to flow the supply fluid toward said pump nozzle inlet across the space therebetween to entrain ambient fluid and deliver the entrained fluid and at least a portion of the supply fluid through the pump nozzle into said conduit whereby the combined flow through said pump nozzle causes slurry to flow through said conduit inlet into said conduit and delivery of the slurry, the supply fluid portion, and entrained fluid to the conduit discharge.

2. A sea sled according to claim 1 including means for adjusting the elevation of said excavating means and said conduit inlet relative to said base structure.

3. A sea sled according to claim 1 including guide means depending from said base structure for maintaining said sled in alignment with the pipeline as the trench is excavated, said guide means including rollers for straddling the pipeline.

4. A sea sled according to claim 3 including a frame for supporting said excavating means, said slurry removal means and said guide means, and means for adjusting the elevation of said frame relative to said base structure thereby to adjust the elevation of said jet nozzles, said conduit and said rollers, relative to said base structure.

5. A sea sled according to claim 1 wherein said slurry removal means includes a second conduit having an inlet disposed below said base structure and a discharge, a second pump nozzle carried by said base structure, said second pump nozzle having an inlet external to said second conduit and exposed to the ambient fluid, said second pump nozzle having an outlet within said conduit for delivery of fluid to said second conduit intermediate the inlet and discharge of said second conduit, a second primary nozzle carried by said base structure external to said second conduit and spaced a predetermined distance from said second pump nozzle inlet, means for supplying fluid under pressure to said second primary nozzle, said second primary nozzle being disposed to flow the supply fluid toward said second pump nozzle inlet across the space therebetween to entrain ambient fluid and deliver the entrained fluid and at least a portion of the supply fluid through said second pump nozzle into said second conduit whereby the combined flow through said second pump nozzle causes slurry to flow through said second conduit inlet into said second conduit and delivery of the slurry, the supply fluid portion, and entrained fluid to the second conduit discharge, said first mentioned and said second conduits being carried by said frame for disposition on respective opposite sides of the pipeline, said conduit discharges having outlet cOnduit portions directed laterally of said sled for disposing the slurry removed from the trench and flowing through said conduits on opposite sides of said trench.

6. A sea sled according to claim 5 wherein said base structure includes a pair of laterally spaced pontoons, and means for ballasting and deballasting said pontoons.

7. A sea sled according to claim 5 including guide means carried by said base structure for maintaining said sled in alignment with the pipeline as the trench is excavated and including rollers for straddling the pipeline, a frame for supporting said excavating means, said slurry removal means and said guide means, and means for adjusting the elevation of said frame relative to said base structure thereby to adjust the elevation of said nozzles, said conduit inlets and said rollers relative to said base structure.

8. A sea sled according to claim 7 wherein each of said conduit inlets has an aperture opening in a lateral inward direction with said apertures lying in substantial lateral registry one with the other.

9. A sea sled according to claim 5 including guide means carried by said base structure for maintaining said sled in alignment with the pipeline as the trench is excavated and including at least a roller each carried by said conduits for straddling the pipeline, each of said rollers lying inwardly of the conduit carrying said roller for engagement with said pipeline, said conduit inlets being comprised of inwardly directed openings in substantial lateral opposition to one another.

10. A sea sled according to claim 5 wherein said base structure includes a pair of pontoons spaced laterally one from the other, guide means carried by said base structure for maintaining said sled in alignment with the pipeline as the trench is excavated and including rollers for straddling the pipeline, a frame for supporting said excavating means, said slurry removal means, and said rollers between said pontoons, and means for ballasting and deballasting said pontoons.

11. A sea sled according to claim 5 wherein each of said primary nozzles is spaced from the corresponding pump nozzle inlet a distance within a range of about 2 to 30 inches.

12. A sea sled according to claim 11 including means mounting each of said primary nozzles for movement into selected positions relative to the corresponding pump nozzle inlets whereby the spacing therebetween is adjustable.

13. A sea sled according to claim 1 wherein said primary nozzle is spaced from the pump nozzle inlet a distance within a range of about 2 to 30 inches.

14. A sea sled according to claim 4 wherein said primary nozzle is spaced from the pump nozzle inlet a distance within a range of about 2 to 30 inches.