Subsea Anti-Cabling System for Multi-Cable Lifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-cable subsea lifting systems face issues with cabling, where imbalanced torsional characteristics lead to axial rotation and potential entanglement of cables, compromising their integrity and increasing operational expenses, especially at greater depths.
Innovation Solution
A multi-cable subsea lifting system equipped with torque measuring devices and subsea anti-cabling devices, each comprising a motor and controller, which impart rotational forces to maintain cable separation and counter torque, thereby preventing cabling and ensuring stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If multi-cable lifting systems are used to handle heavier loads and greater depths, then lifting capacity and operating depth are improved, but cabling occurs due to imbalanced torsional characteristics causing axial rotation and entanglement
Solution Approach 1:
The anti-cabling device applies a preliminary counter-torsional force to the load cable before cabling can occur. The motor-driven spool generates a counter-torsional moment that balances the imbalanced torsional characteristics, preventing axial rotation and entanglement before they can compromise cable integrity
Solution Approach 2:
The anti-cabling device acts as an intermediary between the load cable and the lifting system. It includes a motor-driven spool that winds or unwinds a counter-torsional cable to apply a counter-torsional force, effectively mediating the torsional imbalance without requiring modification to the load cable itself
2Length of moving object
If cable length is increased to reach greater water depths, then operating depth is improved, but the potential for cabling increases due to greater cable extension
Solution Approach 1:
The anti-cabling device applies a preliminary counter-torsional force that scales with cable length. The motor-driven spool generates sufficient counter-torsional moment to balance the imbalanced torsional characteristics over the entire cable length, preventing axial rotation and entanglement even at extended depths
Solution Approach 2:
The system uses torque sensors to monitor the actual torsional load on the cable in real-time. The controller processes this feedback and dynamically adjusts the motor-driven spool to apply the appropriate counter-torsional force, ensuring effective cabling prevention regardless of cable length or depth variations
3Device complexity
If traditional multi-cable lifting systems operate without anti-cabling devices, then device complexity is reduced, but operational expenses increase due to cable recovery difficulties and delays
Solution Approach 1:
The anti-cabling device operates autonomously to prevent cabling, eliminating the need for manual cable recovery interventions. The motor-driven spool automatically applies counter-torsional force based on sensor feedback, and the controller independently adjusts the counter-torsional moment, enabling the system to self-correct torsional imbalances without external intervention
Solution Approach 2:
The system incorporates torque sensors and controllers that continuously monitor cable torsion and automatically adjust the anti-cabling device's counter-torsional force. This closed-loop feedback mechanism detects and corrects torsional imbalances in real-time, preventing cabling before it occurs and eliminating operational delays
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
The system effectively reduces or eliminates cabling, maintaining cable separation and stability, even at deep water depths, allowing for safer and more efficient operation of multi-cable lifting systems.
Implementation Method 1
a torque measuring device associated with each load cable; one or more subsea anti-cabling devices, each anti-cabling device comprising a motor connected to a respective load cable; wherein the controller is configured to actuate each motor to impart a rotational force to its respective load cable in response to measurements obtained from the torque measuring device
Data Source
AI summary
A multi-cable subsea lifting system including two or more load-cable lifting apparatus (2a, 2b); a load cable (4a, 4b) extending from each load-cable lifting apparatus (2a, 2b) to a subsea attachment point; a torque measuring device (22) associated with each load cable (4a, 4b); one or more subsea anti-cabling devices (20), each anti-cabling device (20) including a motor (24) connected to a respective load cable (4a, 4b); and a controller (30) in communication with each motor (24) and torque measuring device (22); wherein the controller (30) is configured to actuate each motor (24) to impart a rotational force to its respective load cable (4a, 4b) in response to measurements obtained from the torque measuring device (22) with the aim to limit cabling, remove cabling or control heading either automatically or from external control.