Data Cable Water Blocking via Segmented Foam and Shielding

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Solution Overview

Problem

Existing data cables face challenges in effectively preventing water penetration without compromising transmission properties, particularly in meeting the MIL-DTL-24643/59 specifications, and require easy removal of water blocking materials during termination to avoid delays and maintain performance.

Innovation Solution

A data cable design incorporating foam insulation around conductors, a solid coat for mechanical support, a filler material for water blocking, a shielding member, a water swellable tape isolated from conductors, and a jacket, which separates water swellable materials from conductors to prevent dielectric property changes and facilitates easy termination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water swellable materials are used for water blocking in data cables, then water penetration resistance is improved, but dielectric properties change and transmission performance deteriorates

Engineering Contradiction:

Improvewater penetration resistanceVSAvoiddata transmission quality

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The cable structure is segmented into distinct functional layers: water swellable material forms an outer water-blocking layer, while conductors are isolated within inner insulation and shielding layers. This segmentation allows the water swellable material to perform its water-blocking function without its dielectric changes affecting the transmission properties of the conductors.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A shielding member acts as an intermediary barrier between the water swellable material and the conductors. The shielding layer physically separates these components, preventing the dielectric properties of the water swellable material from influencing the electrical transmission characteristics of the cable core.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If water blocking materials are applied to conductors, then water penetration resistance is improved, but termination time increases due to difficult removal

Engineering Contradiction:

Improvewater penetration resistanceVSAvoidtermination time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The water blocking function is segmented from the conductor structure and placed in an outer layer. This allows terminators to strip away the outer water-blocking layer without having to remove material from the conductors themselves, significantly reducing termination time while maintaining water protection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The water swellable material is extracted from direct contact with conductors and placed in an outer water-blocking layer. This extraction allows the water blocking function to be removed independently during termination, eliminating the time-consuming process of removing water blocking material from conductor surfaces.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If laminate foil is bonded to polymeric material for water blocking, then water penetration resistance is improved, but structural integrity deteriorates under impact and bending

Engineering Contradiction:

Improvewater penetration resistanceVSAvoidstructural integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The water-blocking mechanism is changed from relying on the mechanical integrity of bonded laminate foil to using the swelling action of water-reactive material. This parameter change allows the water-blocking layer to remain flexible and resistant to cracking under impact and bending, while still providing effective water protection when activated.

Inventive Principle:

Principle #35Parameter changes

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 effectively blocks water penetration while maintaining transmission properties, meeting or exceeding MIL-DTL-24643/59 requirements and minimizing propagation delay and delay skew, ensuring reliable data transmission in harsh environments.

Implementation Method 1

water swellable tape, a water swellable material isolated from the conductors by the shielding member

Methodology Applied

Scientific EffectWater swelling: Absorption (physical)

Implementation Method 2

a first conductor substantially surrounded by a first foam, a second conductor longitudinally adjacent the first conductor and substantially surrounded by a second foam

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 3

water can travel by capillary action along the cable interstices, causing problems in conductivity

Methodology Applied

Scientific EffectCapillary action blocking: Capillary Action

Data Source

PatentUS8440909B2Data cable with free stripping water blocking material

Publication Date: 2013.05.14 GENERAL CABLE TECH CORP

AI summary

A data cable with free stripping water blocking material includes a first conductor substantially surrounded by a first foam, a second conductor longitudinally adjacent the first conductor and substantially surrounded by a second foam, a solid coat substantially surrounding the first foam of the first conductor, a filler material, a shielding member, a water swellable tape, and a jacket. The first conductor with the first foam and the solid coat and the second conductor with the second foam are substantially placed within the filler material. The shielding member is placed substantially around the filler material. The water swellable tape is placed substantially around the shielding member. The jacket is placed substantially around the water swellable tape.