Underwater trenching system

• US 6,022,173 A
• Filed: 06/16/1997
• Issued: 02/08/2000
• 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:
  US08/876,814
• Time in Patent Office: 967 Days
• Field of Search: 405/159-164, 405/158, 37/337-342, 37/347, 37/352
• US Class Current: 405/163
• CPC Class Codes: E02F 5/08 with digging wheels turning round an axis E02F5/109 takes precedence; with digging wheels per se E02F3/18
• 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. An alternative embodiment of the contemplates a frontal high pressure jet array in lieu of the cutter head. The trenching/drive mechanism of the preferred embodiment 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. Other features of the present invention which are taught, and which may be implemented, include G.P.S. (global positioning system) receiver/data transmission for precise monitoring of the system during operations, thruster propulsion, and bottom loading of pipe into the frame via hinged bottom rollers, which may be powered.

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 passage, said pipeline passage also formed through 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 lower rollers supported by roller support members having first and second ends, said first end of each of said roller support members hingedly affixed to one side of said frame, said second end of each of said roller support members releasably affixed to said other side of said frame, so as to provide said roller support members with open, generally vertically aligned positions, and closed, generally horizontally aligned positions, to allow the passage of pipe through the lower end of the frame in said open position, and to allow said lower rollers to generally envelope a portion of the pipe in said closed position;

a high pressure jet array situated generally at said front end of said unit frame, comprising a plurality of jet orifices forwardly emanating from the frame so as to provide a stream of high pressure water streams configured to engage and disperse the seabed, so as to form a trench;

propulsion means associated with said frame, said propulsion means configured to provide thrust directed rearwardly of said frame, in order to propel said frame in a frontal direction;

buoyancy/skid means for alternately 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 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 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 pivot arms being adjustable to position said first and second buoyancy chambers, respectively, to a generally upper position relative said pipeline, away from said seabed, providing buoyancy to the unit frame, said first and second pivot arms being adjustable to position said first and second buoyancy chambers, respectively, 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.

2. The underwater trenching system of claim 1, wherein said invention further includes navigational means for providing a navigational fix of the location of said system to a remote location.

3. The underwater trenching system of claim 2, wherein said navigational means comprises a G.P.S. (global positioning satellite) system.

4. The underwater trenching system of claim 1, wherein said propulsion means comprises rearwardly directed thrusters affixed to said frame.

5. The underwater trenching system of claim 1, wherein said propulsion means comprises propeller driven, first and second pontoons affixed to opposing sides of said frame.