Subsea Cable Core Thermoset Filling for Removable Water Blocking
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Solution Overview
Problem
Subsea power cables face challenges in maintaining water tightness under high pressure and mechanical loads, with existing polymeric materials being difficult to remove for repairs and jointing, and water can flow along the longitudinal direction, especially in large water depths.
Innovation Solution
A subsea power cable design featuring a cable core with a bundle of metal wires arranged in multiple layers, where a two-component hardening composition is introduced as precursors during stranding, forming a thermoset material that fills voids between the metal wires, providing improved water blocking properties by physical bonding and acting as a plug under pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric material is used to fill voids between metal wires for water blocking, then water tightness is improved, but the material becomes difficult to remove for repairs and jointing
Solution Approach 1:
The patent applies parameter changes by using a two-component hardening composition that transitions from a liquid state (easy to remove) to a cured solid state (provides water tightness). The composition comprises a polyol component and an isocyanate component that react upon mixing, changing the physical and chemical parameters of the material to achieve both water blocking and removability requirements
Solution Approach 2:
The patent uses composite materials by combining two different chemical components (polyol and isocyanate) that react to form a cured hardening composition. This composite approach allows the material to exhibit both the water tightness of cured polymers and the removability characteristics of the uncured liquid components
2Ease of manufacture
If polymeric material is intermittently provided along the cable to block water, then manufacturing complexity is reduced, but water can flow through unfilled sections under high pressure
Solution Approach 1:
The patent applies segmentation by dividing the water blocking function into multiple discrete layers of hardening composition distributed along the cable length. Each layer acts as an independent water blocking section, and the cumulative effect of multiple layers provides reliable water protection while maintaining manufacturing simplicity through intermittent application
3Reliability
If adherence between polymeric material and metal surface is increased to improve water blocking, then water tightness is enhanced, but the material becomes harder to remove for repairs
Solution Approach 1:
The patent applies parameter changes by controlling the adherence parameters of the hardening composition through chemical formulation. The two-component system allows adjustment of chemical parameters to achieve optimal balance between water blocking strength and removability, with the cured material providing sufficient adhesion for water protection while remaining removable through controlled chemical or mechanical means
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 design enhances water tightness by ensuring complete filling of voids with a thermoset material that can be easily removed for repairs, maintaining integrity under high pressure and facilitating simplified jointing, suitable for deep-sea applications.
Implementation Method 1
a two-component hardening composition is introduced as precursors during stranding, forming a thermoset material that fills voids between the metal wires
Implementation Method 2
providing improved water blocking properties by physical bonding and acting as a plug under pressure
Data Source
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AI summary
The present invention relates to the technical field of subsea power cables. More specifically, the invention relates to a subsea power cable comprising at least one cable core comprising a bundle of metal wires and more than one layer of a cured two-component hardening composition, wherein the more than one layer of the cured two-component hardening composition is intermittently provided along the longitudinal direction of the power cable. The present invention further relates to a method of manufacturing the power cable according to the invention.