Semi-submersible Float Buoyancy Control via Gravity and Compressed Air

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Solution Overview

Problem

Current semi-submersible offshore wind turbine floats, particularly hybrid steel and concrete structures, face limitations in buoyancy adjustment and operational efficiency due to the complexity and cost of ballast drainage systems.

Innovation Solution

The implementation of a hybrid float design with a central steel column and outer concrete columns connected by pontoon-shaped branches, utilizing gravity-filled ballasts that can be emptied using a shared compressed air system carried by a support vessel, allowing for efficient buoyancy adjustment and reduced installation and operating costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If ballast pumping systems are used to empty ballasts, then buoyancy can be adjusted, but the system complexity and cost increase

Engineering Contradiction:
Improvebuoyancy adjustmentVSAvoidballast drainage system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines multiple ballast drainage functions into a single integrated ballast tank located in the central column. Instead of having separate pumping systems for each column, the invention merges all ballast water evacuation through one common tank and one compressor system, significantly reducing overall system complexity while maintaining full buoyancy control capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The central ballast tank acts as an intermediary reservoir that collects ballast water from all outer columns through gravity-driven flow. This intermediate storage mechanism eliminates the need for direct pumping from each column, simplifying the drainage system architecture while preserving the ability to control buoyancy of individual columns.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If individual ballast pumping systems are installed on each wind turbine, then buoyancy control is available, but installation and operating costs increase

Engineering Contradiction:
Improvebuoyancy controlVSAvoidinstallation cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The support vessel is designed with a universal ballast compressor system that can service multiple wind turbine floats. The same compressor unit can be deployed to different floats sequentially, eliminating the need for each float to have its own dedicated compressor. This multi-functional approach significantly reduces manufacturing and installation costs while maintaining full buoyancy control capability across the wind farm.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If a shared compressed air system on a support vessel is used, then cost is reduced, but system coordination complexity increases

Engineering Contradiction:
Improveoperating costVSAvoidsystem coordination
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The ballast control system is segmented into independent column units, each capable of being filled or emptied independently. The central ballast tank receives water from specific outer columns through dedicated connections, allowing selective control of each column's buoyancy. This segmentation simplifies the coordination required for the shared compressor system, as each column can be managed independently rather than requiring complex centralized control of the entire system.

Inventive Principle:
Principle #1Segmentation

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 design enhances the operational efficiency and cost-effectiveness of offshore wind turbine installation and maintenance by simplifying buoyancy control through a shared compressed air drainage system, reducing the need for multiple ballast pumping systems and enabling easier movement between wind turbines.

Implementation Method 1

the ballasts are gravity-filled and compressed air-emptied ballasts

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

means for connecting the ballasts to a source of compressed drain air

Methodology Applied
Scientific EffectCompressed air: Compression

Data Source

PatentEP3615410B1Semi-submersible float, in particular for a wind turbine
Publication Date: 2023.04.26 SAIPEM SA
  • EP3615410B1 patent drawingFigure 1
  • EP3615410B1 patent drawingFigure 2~3
  • EP3615410B1 patent drawingFigure 4

AI summary

The invention relates to a semi-submersible float (2), in particular for an offshore wind turbine (1), comprising at least four columns, including a central column (3) and three outer columns (4) connected to the central column by arms (7) in the form of a pontoon, the outer columns and the pontoon arms comprising ballasts (10). The float is characterised in that the ballasts (10) are filled by gravity and emptied using compressed air.