Subsea Load Monitoring for Precise Buoyancy Control
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Solution Overview
Problem
Existing subsea lifting operations using ROVs face risks of equipment damage and loss of thruster engine power due to the inability to accurately determine and control buoyancy application, leading to collisions and reduced visibility.
Innovation Solution
A subsea load monitoring apparatus with a load sensor, central processing unit, battery, activation device, and output device, which measures strain to calculate buoyancy and allows operators to fine-tune buoyancy application, reducing the risk of ROV thruster failure and equipment damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of buoyancy elements is determined by mathematical calculations and qualified guessing, then the total weight of the load can be reduced, but the accuracy of buoyancy determination is insufficient leading to ROV thruster power loss and potential collisions
Solution Approach 1:
The patent implements a feedback mechanism where the load sensor continuously measures the actual weight of the subsea load, and this measurement is transmitted to the surface vessel. The operator receives real-time feedback about the load weight and adjusts the number of buoyancy elements accordingly. This closed-loop feedback system eliminates the need for inaccurate mathematical calculations and qualified guessing, enabling precise buoyancy determination and preventing ROV thruster power loss and potential collisions.
2Force
If the ROV uses full thrust to lift a heavy load, then the load can be lifted, but the ROV risks losing thruster engine power and causing collisions or seabed disturbance
Solution Approach 1:
The patent applies preliminary action by having the load sensor measure and transmit the load weight to the surface vessel before the ROV begins the lifting operation. The operator receives this advance information and can pre-calculate the optimal number of buoyancy elements needed. This preliminary measurement and planning eliminate the need for the ROV to use full thrust during lifting, as the buoyancy is properly balanced in advance, preventing thruster power loss and maintaining operational reliability.
3Ease of operation
If a cable-connected monitoring system is used, then continuous power and data transmission are available, but the system becomes more complex and harder to manipulate and move during underwater operations
Solution Approach 1:
The patent extracts the power source from the monitoring system by using a battery-powered load sensor instead of a cable-connected system. The load sensor is equipped with an integrated battery that provides autonomous power, eliminating the need for a physical cable connection to the surface vessel. This extraction of the power source simplifies the overall system structure, making the monitoring apparatus easier to manipulate and move during underwater operations while maintaining continuous monitoring capability.
4Speed
If the central processing unit operates continuously, then real-time processing is available, but the battery drains quickly reducing operational duration
Solution Approach 1:
The patent implements periodic action by having the central processing unit operate in cycles rather than continuously. The CPU processes measurements and transmits data to the surface vessel at predetermined time intervals. During these intervals, the CPU remains in a low-power state. This periodic operation maintains real-time monitoring capability while significantly reducing battery power consumption, thereby extending the operational duration of the battery-powered load sensor.
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
Enhances control over buoyancy application, reducing the risk of ROV thruster failure and equipment damage by enabling precise buoyancy adjustments during subsea lifting operations.
Implementation Method 1
The subsea load monitoring apparatus can be used to measure the strain between the first and second end of the load sensor
Implementation Method 2
buoyancy elements are usually mounted onto the load to be lifted. This is to reduce the total weight of the load to be lifted by the ROV
Data Source
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AI summary
The invention relates to a subsea load monitoring apparatus (1) comprising: - a load sensor (40) having a first end (41) and a second end (42); - a central processing unit (61) configured for processing measurements from the load sensor (40); - a battery (60) for powering the central processing unit (61); - an activation device (63) being configured for activating the central processing unit (61) from an idle operational mode to an active operational mode; - a first and a second load attachment means (51, 52) connected to the first and second end (41, 42) of the load sensor (40), respectively; and - an output device (90) for the processed measurements from the load sensor (40). The invention relates furthermore to a subsea load monitoring system (10) and methods for use of the subsea load monitoring system (10).