Subsea Pipeline Lifting Frame with Hinge-Mounted Relocation
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Solution Overview
Problem
Existing lifting frames for subsea pipelines are bulky and difficult to relocate efficiently, requiring large and expensive installation vessels, and there is a need for a system that simplifies the relocation process to avoid missing weather windows.
Innovation Solution
A lifting system comprising removable lifting frames that mount onto paired subsea foundations, with one foundation having a hinge component and the other defining a platform for foot positioning, allowing the frame to pivot and adjust to compensate for differences in level and alignment, enabling easy transfer between locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional bulky lifting frames are used to bridge over the pipeline, then structural strength and stability are improved, but device complexity and difficulty of relocation increase
Solution Approach 1:
The lifting frame is divided into separate modular components including legs, crossbeams, and foundation elements that can be independently assembled and disassembled. This segmentation allows the frame to be broken down into manageable sections for easier relocation while maintaining structural integrity during operation.
Solution Approach 2:
The lifting frame incorporates movable and adjustable elements such as telescopic legs, rotating joints, and flexible connections that enable dynamic adaptation during assembly, relocation, and operation. These dynamic features allow the rigid structure to be transformed into a more compact configuration for transport.
2Ease of operation
If large installation vessels are used to handle bulky lifting frames, then ease of operation is improved, but cost increases
Solution Approach 1:
By segmenting the lifting frame into smaller modular units, the system can be handled by smaller, more cost-effective vessels or even standard support ships, eliminating the need for expensive large-scale installation vessels while maintaining operational capability.
Solution Approach 2:
The patent introduces intermediate handling components such as cranes, spreaders, and modular assembly fixtures that serve as mediators between the segmented frame components and the installation vessel, enabling efficient assembly and relocation using smaller, more economical vessels.
3Manufacturing precision
If relocation is delayed to ensure proper alignment, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The foundation elements and guide structures are pre-installed and pre-positioned on the seabed before the lifting frame arrives. This preliminary action establishes reference points and alignment guides that enable rapid, accurate positioning of the frame components without time-consuming adjustments during relocation.
Solution Approach 2:
The patent replaces complex mechanical alignment systems with simplified positioning mechanisms such as guide rails, keyed connections, and pre-drilled alignment holes that automatically guide components into correct positions, reducing the time and skill required for precise alignment during relocation.
Data Source
AI summary
A lifting system and a method of installing a lifting frame for lifting a subsea pipeline has paired subsea foundations spaced apart from each other by a gap through which the pipeline extends. A removable lifting frame is mounted on the foundations to bridge over the pipeline disposed in the gap. The lifting frame comprises a pair of feet that are cooperable with respective support formations on the foundations. One support formation defines a hinge component to restrain one of the feet for pivotal movement. The other support formation defines a platform on which the other foot can rest in various positions within a support area. This compensates for differences in level, spacing or alignment between the foundations. The lifting frame can be transferred to another location by dismounting it from a first pair of foundations and then mounting it onto a second pair of foundations in a corresponding manner.