Snap-Fit Modular Buoyancy Element for Faster Subsea Installation

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Solution Overview

Problem

The installation of subsea cables and pipelines is time-consuming due to the labor-intensive process of connecting buoyancy modules using bolts or straps, increasing costs significantly.

Innovation Solution

A modular buoyancy element with snap-fastening elements allows for quick assembly and disassembly, featuring a hook member that snaps into a receptacle member, enabling automated installation using a clamp device and conveyor system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bolts or straps are used to interconnect buoyancy modules, then the connection strength and reliability are improved, but the installation time and labor costs increase considerably

Engineering Contradiction:
Improveconnection strengthVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The buoyancy element is divided into multiple modular buoyancy modules that can be connected together. Each module is a self-contained unit with standardized fastening elements, allowing for segmented assembly that is both reliable and time-efficient. The modules can be pre-assembled and then quickly connected on-site using the snap-fastening system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fastening elements (protruding and recessed parts) are pre-formed and integrated into the buoyancy modules during manufacturing. This preliminary preparation of connection features eliminates the need for现场 drilling, bolting, or strap tightening, enabling rapid assembly while maintaining strong connections.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 3:

The traditional mechanical fastening system (bolts, nuts, straps requiring manual tightening) is replaced with a snap-fit fastening system. The protruding fastening element of one module snaps into the recessed fastening element of another module, providing reliable connection without requiring time-consuming manual fastening operations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional fastening methods are used, then secure connection is achieved, but the production costs increase due to extended installation time

Engineering Contradiction:
Improveconnection securityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fastening elements are merged into the buoyancy module structure itself rather than being separate components. The protruding and recessed fastening features are integrated directly into the molded buoyancy modules, eliminating the need for separate fasteners and reducing overall system complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The snap-fit fastening system uses simple, inexpensive molded features rather than expensive metal fasteners. While the individual fastening elements are simple and low-cost, the system provides sufficient reliability for the application while dramatically reducing material and labor costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If manual assembly processes are used, then flexibility in installation is maintained, but productivity and installation speed decrease

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidinstallation speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The buoyancy modules are designed to be self-aligning and self-assembling. The protruding fastening element of one module automatically engages with the recessed fastening element of another module when brought together, eliminating the need for complex alignment procedures or specialized installation tools while maintaining operational simplicity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3306157B1Modular buoyancy element
Publication Date: 2021.12.15 NEXANS SA
  • EP3306157B1 patent drawingFigure 1
  • EP3306157B1 patent drawingFigure 2~3
  • EP3306157B1 patent drawingFigure 4

AI summary

The buoyancy element (10) comprises a plurality of, and preferably two, buoyancy modules (16,22) interconnected to form a buoyancy element around an electrical cable or a pipeline, wherein a first buoyancy module (16) is provided with at least one first fastening element (28) and a second buoyancy module (22) is provided with at least one second fastening element (34), and wherein the first fastening element (28) comprises a snap element that snaps onto the second fastening element (34) when the first buoyancy module (16) is secured to the second buoyancy module (22). According to one aspect, a single embodiment of the buoyancy module comprises both the first fastening element (28) and the second fastening element (34), oriented such that two identical buoyancy modules may be clamped together, whereby mutually cooperating first and second fastening elements of the respective modules align in locking engagement. This aspect of the invention reduces production costs, as only a single type of module needs to be manufactured.