Dynamic Slip Clutch Torque Control for Offshore Umbilical Reels
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Solution Overview
Problem
Umbilical reels in deepwater offshore services face issues with excessive tension during deployment, leading to potential destruction of the umbilical and risk of injury due to locked spool positions or loss of air pressure, which existing systems fail to manage effectively.
Innovation Solution
A motorized offshore reel system with a slip clutch assembly and torque controller that automatically adjusts slipping torque to maintain constant tension, counts spool revolutions, and determines the current radius of the cable to apply maximum torque in emergencies, ensuring calibrated torque settings in field conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed preset torque is used in the slip clutch, then the device complexity is reduced, but the tension on the umbilical varies excessively as the spool diameter decreases during deployment
Solution Approach 1:
The slip clutch torque is made dynamic rather than fixed. The controller automatically adjusts the slip clutch torque during deployment based on spool radius measurements, allowing the torque to vary as the spool diameter decreases. This dynamic adjustment maintains constant umbilical tension despite changing spool geometry.
Solution Approach 2:
The system changes the torque parameter of the slip clutch during operation. By measuring spool radius and calculating required torque, the system adjusts the slip clutch torque parameter in real-time to compensate for decreasing spool diameter, thereby maintaining constant tension on the umbilical.
2Device complexity
If the spool is locked in position by brakes, motor, or locking pin, then the reel structure is simplified, but excessive tension can destroy the umbilical and injure personnel
Solution Approach 1:
The system implements feedback control by monitoring spool rotation and tension conditions. The controller continuously assesses deployment status and automatically adjusts slip clutch torque to prevent excessive tension, providing feedback-based safety without requiring complex locking mechanisms.
Solution Approach 2:
The slip clutch acts as an intermediary safety device between the motor and the umbilical. It provides a controlled slipping mechanism that prevents excessive tension from reaching the umbilical, serving as a protective intermediary that eliminates the need for rigid locking mechanisms.
3Reliability
If the slip clutch allows spool rotation at fixed preset torque, then the umbilical is protected from excessive tension, but the tension increases from 1,000 to over 3,000 pounds as the spool becomes empty
Solution Approach 1:
The system dynamically changes the torque parameter of the slip clutch during deployment. By measuring spool radius and calculating the required torque to maintain constant tension, the controller adjusts the slip clutch torque in real-time, preventing tension from increasing as the spool becomes empty.
Solution Approach 2:
The system replaces the purely mechanical fixed-torque slip clutch with a controlled system that uses sensors and a controller to adjust torque. This substitution of mechanical control with automated control enables precise tension management throughout the deployment process.
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 maintains constant tension on the umbilical during deployment, preventing damage and injury by dynamically adjusting torque based on spool radius and layer changes, ensuring safe operation and equipment protection.
Implementation Method 1
A slip clutch has sometimes been added to the reel to allow the spool to turn when a relatively fixed preset tension limit on the umbilical is exceeded
Data Source
AI summary
The method of preventing over tension to an umbilical wrapped on the spool of an offshore reel when the umbilical is being normally deployed or retrieved or when the umbilical is unexpectedly pulled from the spool on the reel, comprising providing a main disk, mounting the main disk on the spool of the reel with a slip connection which will be automatically controlled, connecting motor power for the reel to the main disk, connecting brakes to the main disk, such that when the diameter of deployment varies the slip connection torque will be automatically adjusted and prevent the umbilical from being subjected to tension higher than the desired amount.