Underwater Cable Double Jacket Water Resistance

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Solution Overview

Problem

Cables used in damp or wet environments, especially underwater, face water diffusion issues due to non-waterproof plastic sheathing, leading to signal quality deterioration and potential failure in digital signal transmission, as existing solutions like metallic layers compromise flexibility and are not suitable for all applications.

Innovation Solution

A cable with a double jacket structure featuring a hydrophobic inner layer made of non-polar polyolefinic plastic and a softer, polar polyurethane outer layer, where the inner layer is chemically functionalized and surface-activated to form a form-tight and pressure-tight connection with the outer layer, preventing water ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metallic intermediate layer is integrated into the cable to achieve watertightness, then water diffusion is prevented, but the cable becomes rigid and unsuitable for most applications

Engineering Contradiction:
ImprovewatertightnessVSAvoidcable flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies composite materials by combining two different plastic materials with distinct properties: an inner layer made of a material with low water diffusion rate and an outer layer made of a softer material suitable for connectors and housings. This composite structure achieves watertightness while maintaining flexibility, eliminating the need for rigid metallic layers.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the inner layer is made of harder polyurethane with lower diffusion rate, then water penetration is reduced, but the connection between inner and outer cladding layers becomes vulnerable to mechanical loads from pressure changes

Engineering Contradiction:
Improvewater resistanceVSAvoidconnection strength between layers
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a transition zone between the inner and outer cladding layers through controlled interpenetration of the materials. The inner layer material extends into the outer layer and vice versa, forming an interlocked structure that locally reinforces the connection while maintaining the overall water resistance properties of both layers.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If water diffuses into the cable structure through plastic sheathing, then the cable remains flexible, but signal quality deteriorates and transmission may fail

Engineering Contradiction:
Improvecable flexibilityVSAvoidsignal transmission quality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the cable sheath into multiple functional layers: an inner layer specifically designed with low water diffusion properties to protect the signal-carrying elements, and an outer layer providing flexibility and mechanical protection. This segmented structure isolates the signal transmission elements from water ingress while preserving cable flexibility.

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

The solution ensures reliable digital signal transmission in wet environments by preventing water penetration between the jacket layers, maintaining signal quality and flexibility, suitable for underwater and high-pressure applications without the rigidity issues associated with metallic layers.

Implementation Method 1

at least one of the two cladding layers, in particular the inner cladding layer, is chemically functionalized

Methodology Applied
Scientific EffectChemical functionalization: Chemical Bonding

Implementation Method 2

the surface of at least one of the cladding layers, specifically the surface of the inner cladding layer, is activated during production

Methodology Applied
Scientific EffectSurface activation: Plasma

Implementation Method 3

a first, inner and hydrophobic jacket layer made of a non-polar polyolefinic plastic

Methodology Applied
Scientific EffectHydrophobic effect: Hydrophobe

Data Source

PatentEP3391388B1Cable and method for producing the cable
Publication Date: 2020.07.01 LEONI KABEL GMBH
  • EP3391388B1 patent drawingFigure 1

AI summary

The cable is used, in particular, as an underwater cable and comprises a central element, which is surrounded by a cable sheath, which has an inner hydrophobic sheath layer made of a first plastic and an outer sheath layer applied to same and made of a different plastic to the inner sheath layer, wherein a polyolefin-type plastic is used for the inner sheath layer, wherein one of the sheath layers, in particular the inner sheath layer is chemically functionalised, and wherein a sealed connection is formed between the two sheath layers.