Flexible Line Tensioner Torque Control During Waterborne Immobilization
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Solution Overview
Problem
The existing method for laying and recovering flexible lines in water bodies results in an imbalance of loads between upper and lower tensioners during immobilization phases, leading to potential overloading of lower tensioners, which can compromise safety and necessitate oversized equipment or reduced line capacity.
Innovation Solution
The method involves activating both upper and lower gripping mechanisms to apply a holding torque to the flexible line, with controlled motor movements during immobilization phases to maintain load balance, using sensors to measure load differences and adjust motor activity accordingly to prevent excessive load on lower tensioners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical brakes are activated to stop the laying process, then the line can be immobilized for various operations, but the load on lower tensioners increases relative to upper tensioners, causing load imbalance and potential overloading
Solution Approach 1:
The system dynamically switches between mechanical brake mode and motor torque control mode based on operational needs. During immobilization phases, motors remain active to apply compensating torque that balances the load between upper and lower tensioners, replacing the static mechanical brake approach with a dynamic active control system.
Solution Approach 2:
The control unit continuously monitors the loads on upper and lower tensioners and adjusts motor torque in real-time to maintain load balance. This feedback mechanism detects load imbalances and automatically compensates by modulating motor output, ensuring stable immobilization without overloading lower tensioners.
2Reliability
If safety coefficients are increased to prevent lower tensioner overloading, then safety is improved, but equipment must be oversized or line capacity is reduced
Solution Approach 1:
The active torque control system allows each tensioner to self-regulate its load contribution during immobilization phases. By having motors actively manage torque distribution, the system eliminates the need for conservative oversizing, allowing tensioners to be sized for their actual operational requirements rather than worst-case static scenarios.
3Adaptability or versatility
If frequent immobilizations are performed for operations like buoy placement or repairs, then operational flexibility is improved, but load imbalance and overloading risks increase
Solution Approach 1:
The system provides dynamic torque control that adapts to frequent immobilization cycles. Motors can be quickly activated to balance loads during each immobilization event, enabling frequent stops for operations like buoy placement, repairs, or underwater interventions without compromising tensioner reliability.
Solution Approach 2:
The motor torque control maintains continuous active management of tensioner loads throughout the entire immobilization duration. Rather than passive mechanical braking, the system continuously adjusts motor output to balance loads, ensuring reliability is maintained even during frequent and extended immobilization periods.
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 approach allows for frequent immobilizations without overloading lower tensioners, ensuring safety and maintaining equipment performance by balancing loads and preventing unnecessary oversizing or undersizing of tensioners.
Implementation Method 1
activation of the motor of at least one upper gripping mechanism (or tensioner) and/or at least one lower gripping mechanism (or tensioner), in order to apply to the movement member of the upper gripping mechanism (or tensioner) and/or of the lower gripping mechanism (or tensioner) a torque for retaining the line against its weight
Data Source
AI summary
A method including at least one phase of near-immobilization or immobilization of the line, including the following steps: activation of the motor of at least one upper tensioner and/or of at least one lower tensioner by a control unit, in order to apply to the movement member of the upper tensioner and/or of the lower tensioner, a holding torque to hold the line against its weight; at least occasional control by the control unit of at least one motor of an upper tensioner and/or of a lower tensioner for causing a movement member of the upper tensioner and/or lower tensioner to move or for changing the holding torque applied to the movement member of the upper tensioner and/or of the lower tensioner.