Underwater Excavation Thruster Orientation
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Solution Overview
Problem
Underwater excavation apparatuses face instability and orientation challenges, particularly when operating in inclement weather, due to reactive torque and the need to maintain precise alignment with subsea pipelines or cables, which is difficult with existing single-impeller systems.
Innovation Solution
The apparatus incorporates a moving means, such as thrusters, for orienting, positioning, and counteracting reactive torque, allowing for rotational and directional movement, enabling precise placement and orientation of the excavation apparatus using a pair of impellers driven in contra-rotating directions and connected via a drilling motor system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single impeller is used in the excavation apparatus, then the device complexity is reduced, but the stability of the apparatus deteriorates due to reactive torque
Solution Approach 1:
The patent applies the counterweight principle by using a second impeller that rotates in the opposite direction to the first impeller. This second impeller generates reactive torque that counteracts the reactive torque from the first impeller, thereby stabilizing the excavation apparatus and preventing unwanted rotation. The contra-rotating impellers balance each other's reactive forces, solving the stability problem while maintaining operational effectiveness.
Solution Approach 2:
The patent employs asymmetry by configuring the impellers to rotate in opposite directions rather than in the same direction. This asymmetric rotation pattern creates counteracting reactive torques that stabilize the apparatus. The asymmetric design of contra-rotating impellers allows the system to eliminate the destabilizing effect of single-impeller reactive torque while maintaining the benefits of multiple impellers.
2Ease of operation
If tugger lines are used to maintain orientation, then the ease of operation is improved, but the reliability deteriorates in inclement weather due to wind and tide effects
Solution Approach 1:
The patent replaces the mechanical tugger line system with a thruster-based propulsion system. Instead of relying on external tugger lines that are vulnerable to wind and tide forces, the excavation apparatus is equipped with self-contained thrusters that generate propulsion force directly. This substitution of the mechanical control system with an active propulsion system eliminates the reliability issues associated with tugger lines in inclement weather while maintaining ease of orientation control.
Solution Approach 2:
The thruster system enables the excavation apparatus to maintain its own position and orientation autonomously without requiring external assistance from tugger lines. The self-service capability allows the apparatus to counteract environmental forces like wind and tides independently, improving reliability while maintaining operational ease through direct control of the thrusters.
3Adaptability or versatility
If the vessel takes a heading different from the pipeline direction to account for wind and tide, then the adaptability to weather conditions is improved, but the difficulty of maintaining correct excavator orientation increases
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the position and orientation of the excavation apparatus relative to the pipeline and actively adjusts the thruster forces to maintain correct alignment. This feedback mechanism allows the system to compensate for vessel heading changes caused by wind and tide, automatically correcting orientation deviations without increasing operational difficulty. The sonar detection means provide real-time feedback on position relative to the pipeline, enabling continuous orientation correction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the stability and precision of underwater excavation by allowing the apparatus to maintain correct orientation and position, even in adverse weather conditions, using thrusters for precise control and movement, thereby improving excavation efficiency and accuracy.
Implementation Method 1
The thruster may be capable of causing movement of the excavation apparatus by causing jets of fluid
Implementation Method 2
The at least one moving means may comprise means for orienting, positioning, rotating (e.g. in use around at least one substantially vertical axis and/or at least one horizontal axis), counteracting reactive torque and/or steering the apparatus
Data Source
AI summary
An underwater excavation apparatus having various mechanisms for moving the underwater excavation apparatus that are provided on or adjacent to the apparatus is described. The mechanisms for moving the underwater excavation apparatus provide for orienting, positioning, rotating, counteracting reactive torque and/or steering the apparatus.