Underwater trenching system

• US 5,456,551 A
• Filed: 01/13/1994
• Issued: 10/10/1995
• Est. Priority Date: 01/13/1994
• Status: Expired due to Fees

• Current Assignee: Saint E. Saxon
• Original Assignee: Saint E. Saxon
• Inventors: Saxon, Saint E.
• Primary Examiner(s): Taylor, Dennis L.
• Application Number:
  US08/182,971
• Time in Patent Office: 635 Days
• Field of Search: 405/161, 405/162, 405/160, 405/163, 405/164, 405/158, 37/323, 37/329, 37/94, 37/337, 299/13, 299/14
• US Class Current: 405/163
• 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 5/105 self-propulsed units moving on the underwater bottom
• 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: E02F 5/109 using rotating digging elements rotating digging elements per se E02F3/18
• CPC Class Codes: E02F 9/06 Floating substructures as supports floating installations with arrangements acting by a sucking or forcing effect E02F3/8833

Abstract

A self-guided system for trenching water bottoms for the installation of a pipeline. The preferred embodiment of the present invention teaches a system which is configured to be mounted about the pipeline to be buried, and which further contemplates a uniquely configured, forward mounted trenching/drive mechanism incorporating a cutter wheel generally about the width of the desired trench, the mechanism configured to propel the system as well as trench the desired area. The trenching/drive mechanism of the present invention further includes a high pressure spray array mounted about the frontal cutter wheel area, and a suction/mud pump assembly to the rear of the cutter wheel. The high pressure spray array provides the dual purpose function of loosening the area to be trenched, as well as cleaning and removing the trenched matter from the cutter wheel. The present invention further includes first and second buoyancy chambers which are configured to be uniformly lowered to the lower periphery of the unit frame, to provide skids for utilization of the present system in shallow water. An alternative embodiment of the present invention teaches the incorporation of a framed system similar to that as taught in the present invention, but without the trenching/drive mechanism, and with the addition of a pipe cutter mounted to the rear of the unit frame, for utilization of pipeline recovery and dismemberment operations.

Claims

1. An underwater trenching system for forming a trench in a seabed under water, and installing a pipeline into said trench, comprising:

a unit frame, said frame having upper and lower ends with a medial area therebetween, first and second sides, and a front and rear end, said medial area of said frame having formed longitudinally therethrough a pipeline conduit, said pipeline conduit also formed through said first side and said front and rear ends, said medial area further comprising upper and lower rollers configured to engage and roll along the pipeline to be installed;

a trenching/drive mechanism emanating from said lower front end of said unit frame, comprising a cutter housing having a front, open area tapering to a rear area of lesser width and height of said front, open area, said front, open area having disposed therein a cutter wheel on an axle generally transversely situated relative the longitudinal axis of said unit frame, said cutter wheel having an axle length generally about corresponding with the width of said unit frame, said cutter wheel having a diameter generally corresponding with the desired depth of said trench to be formed in said seabed, said cutter wheel further comprising a plurality of cutting blades configured to cut and scoop out said seabed, said cutter wheel configured to rotate in a forward direction, driving the front end of said unit frame forward, and rolling said unit frame along the pipeline via said upper and lower rollers, as said cutter wheel'"'"'s cutting blades cuts and scoops out said seabed and debris.

2. The underwater trenching system of claim 1, wherein said invention further includes suction means for providing suction to said rear area of said cutter housing, said suction means for collecting and diverting cut seabed and debris from said cutter housing front, open area through said cutter housing rear area.

3. The underwater trenching system of claim 2, wherein said suction means comprises a high pressure mud pump, and wherein there is further included jetting means for diverting said cut seabed and debris collected and diverted by said suction means from the cutter housing rear area to the rear of said unit frame, jetting said cut seabed and debris away from the rear of said unit frame in such a manner as to drive said unit frame forward, rolling said unit frame along the pipeline via said upper and lower rollers in said medial area of said frame.

4. The underwater trenching system of claim 1, wherein said cutter housing is pivotally connected to said front, lower end area of said unit frame.

5. The underwater trenching system of claim 4, wherein said cutter housing may be pivotally manipulated relative said unit frame via a reciprocating piston having first and second ends, said first end in communication with said frame, said second end in communication with said cutter housing.

6. The underwater trenching system of claim 1, wherein said medial area of said frame includes an upper support frame, and wherein there is further included first and second pivot support arms having first and second ends, said first ends of said pivot Support arms affixed to the medial area of said upper support frame, said second ends of said pivot support arms each having affixed thereto an upper support roller, said pivot support arms configured to pivot in such a manner as to laterally adjust said upper rollers.

7. The underwater trenching system of claim 6, wherein there is further included lateral adjustment means for laterally adjusting said upper support rollers, said lateral adjustment means further comprising first and second lateral adjustment shafts having first and second ends, said first ends of said lateral adjustment shafts pivotally affixed to said first and second pivot support arms, respectively, said lateral adjustment means further comprising first and second screwjacks affixed to said unit frame, said first and screwjack configured to engage said second end of said first pivot support arm, said second screwjack configured to engage said second end of said second pivot support arm.

8. The underwater trenching system of claim 7, wherein there is further included a first and second proximity switches mounted in or near said medial area of said unit frame, said proximity switches configured to engage and become activated upon contact with an obstacle along said pipeline, said first proximity switch mounted near said front end of said unit frame, said second proximity switch mounted near said rear end of said unit frame, said first proximity switch configured to engage one of said screwjacks in such a manner as to raise at least one of said lateral adjustment shafts, raising at least one of said upper rollers, said second proximity switch configured to engage one of said screwjacks in such a manner as to lower at least one of said lateral adjustment shafts, lowering at least one of said rollers.

9. The underwater trenching system of claim 1, wherein there is further included a mud lift comprising a lateral column having first and second ends and upper and lower areas, and a medial area therebetween, said lateral column mounted to said unit frame, said first end of said of said lateral column having attached thereto a mud pump, said mud pump having a jetting orifice directed rearward of said unit frame, said second end of said lateral column having an intake opening adjacent to or below the lower end of said unit frame, said medial area of said lateral column configured to slidingly telescope into said upper or lower areas of said lateral column, forming an opening in the vicinity of the medial area of said unit frame.

10. The underwater trenching system of claim 1, wherein there is provided buoyancy/skid means for alternatively providing buoyancy or skids for said unit frame, said buoyancy/skid means further comprising first and second pivot arms each having first and second ends, said first ends pivotally affixed to said unit frame, said first and second pivot arms extending in opposing directions generally away from said unit frame, said second end of said first pivot arm attached to a first buoyancy chamber, said second end of said second pivot arm attached to a second buoyancy chamber, said first and second buoyancy chambers generally axially aligned with the longitudinal axis of said unit frame, said first and second buoyancy chambers extending in spaced relationship from opposing side walls of said unit frame, said first and second pivot arms being adjustable to position said pontoons from a generally upper position relative said pipeline, away from the seabed, providing buoyancy to the unit frame, said first and second pivot arms being adjustable to position said pontoons to a generally lower position wherein said pontoons are lowered to contact said seabed, providing skids for supporting said unit frame on or over said seabed.

11. An underwater trenching system for forming a trench in a seabed under water, and installing a pipeline into said trench, comprising:

a unit frame, said frame having upper and lower ends with a medial area therebetween, first and second sides, and a front and rear end, said medial area of said frame having formed longitudinally therethrough a pipeline conduit, said pipeline conduit also formed through said first side and said front and rear ends, said medial area further comprising upper and lower rollers configured to engage and roll along the pipeline to be installed;

buoyancy/skid means for alternatively providing buoyancy or skids for said unit frame,

said buoyancy/skid means further comprising first and second pivot arms each having first and second ends, said first ends pivotally affixed to said unit frame, said first and second pivot arms extending in opposing directions generally away from said unit frame, said second end of said first pivot arm attached to a first buoyancy chamber, said second end of said second pivot arm attached to a second buoyancy chamber, said first and second buoyancy chambers generally axially aligned with the longitudinal axis of said unit frame, said first and second buoyancy chambers extending in spaced relationship from opposing side walls of said unit frame, said first and second pivot arms being adjustable to position said pontoons from a generally upper position relative said pipeline, away from the seabed, providing buoyancy to the unit frame, said first and second pivot arms being adjustable to position said pontoons to a generally lower position wherein said pontoons are lowered to contact said seabed, providing skids for supporting said unit frame on or over said seabed.

12. The underwater trenching system of claim 11, wherein said medial area of said frame includes an upper support frame, and wherein there is further included first and second pivot support arms having first and second ends, said first ends of said pivot support arms affixed to the medial area of said upper support frame, said second ends of said pivot support arms each having affixed thereto an upper support roller, said pivot support arms configured to pivot in such a manner as to laterally adjust said upper rollers.

13. The underwater trenching system of claim 12, wherein there is further included lateral adjustment means for laterally adjusting said upper support rollers, said lateral adjustment means further comprising first and second lateral adjustment shafts having first and second ends, said first ends of said lateral adjustment shafts pivotally affixed to said first and second pivot support arms, respectively, said lateral adjustment means further comprising first and second screwjacks affixed to said unit frame, said first and screwjack configured to engage said second end of said first pivot support arm, said second screwjack configured to engage said second end of said second pivot support arm.

14. The underwater trenching system of claim 13, wherein there is further included a first and second proximity switches mounted in or near said medial area of said unit frame, said proximity switches configured to engage and become activated upon contact with an obstacle along said pipeline, said first proximity switch mounted near said front end of said unit frame, said second proximity switch mounted near said rear end of said unit frame, said first proximity switch configured to engage one of said screwjacks in such a manner as to raise at least one of said lateral adjustment shafts, raising at least one of said upper rollers, said second proximity switch configured to engage one of said screwjacks in such a manner as to lower at least one of said lateral adjustment shafts, lowering at least one of said rollers.

15. The underwater trenching system of claim 11, wherein there is further included a mud lift comprising a lateral column having first and second ends and upper and lower areas, and a medial area therebetween, said lateral column mounted to said unit frame, said first end of said of said lateral column having attached thereto a mud pump, said mud pump having a jetting orifice directed rearward of said unit frame, said second end of said lateral column having an intake opening adjacent to or below the lower end of said unit frame, said medial area of said lateral column configured to slidingly telescope into said upper or lower areas of said lateral column, forming an opening in the vicinity of the medial area of said unit frame.

16. An underwater trenching system for forming a trench in a seabed under water, and installing a pipeline into said trench, comprising:

a unit frame, said frame having upper and lower ends with a medial area therebetween, first and second sides, and a front and rear end, said medial area of said frame having formed longitudinally therethrough a pipeline conduit, said pipeline conduit also formed through said first side and said front and rear ends, said medial area further comprising upper and lower rollers configured to engage and roll along the pipeline to be installed;

said medial area of said frame further comprising an upper support frame,

first and second pivot support arms having first and second ends, said first ends of said pivot support arms affixed to the medial area of said upper support frame, said second ends of said pivot support arms each having affixed thereto an upper support roller, said pivot support arms configured to pivot in such a manner as to laterally adjust said upper rollers;

lateral adjustment means for laterally adjusting said upper support rollers, said lateral adjustment means further comprising first and second lateral adjustment shafts having first and second ends, said first ends of said lateral adjustment shafts pivotally affixed to said first and second pivot support arms, respectively, said lateral adjustment means further comprising first and second screwjacks affixed to said unit frame, said first and screwjack configured to engage said second end of said first pivot support arm, said second screwjack configured to engage said second end of said second pivot support arm.

first and second proximity switches mounted in or near said medial area of said unit frame, said proximity switches configured to engage and become activated upon contact with an obstacle along said pipeline, said first proximity switch mounted near said front end of said unit frame, said second proximity switch mounted near said rear end of said unit frame, said first proximity switch configured to engage one of said screwjacks in such a manner as to raise at least one of said lateral adjustment shafts, raising at least one of said upper rollers, said second proximity switch configured to engage one of said screwjacks in such a manner as to lower at least one of said lateral adjustment shafts, lowering at least one of said rollers.