Water-Cooled Cable Sheath Layout for Wear and Cooling Balance

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Solution Overview

Problem

Existing water-cooled copper cables used in high-current applications suffer from reduced lifespan due to electromagnetic forces causing cable oscillations, rubbing, and mechanical stress, leading to early wear and tear, especially in environments with intense electromagnetic fields.

Innovation Solution

Applying a uniform thickness covering sheath onto all copper ropes within the cable, which is subsequently pierced, to enhance rigidity and reduce friction and mechanical stress, while maintaining effective cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pre-pierced sheath is fitted onto only half of the copper ropes, then wearing caused by friction is limited, but heat exchange with cooling water is compromised

Engineering Contradiction:
Improvewearing resistanceVSAvoidheat exchange efficiency
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies local quality by differentiating the treatment of ropes: some ropes are completely covered with sheath for wearing protection, while other ropes remain exposed for optimal heat exchange. This selective application resolves the contradiction between friction resistance and thermal efficiency.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the sheath is made to be directly pierced during extrusion, then non-uniform coverage is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvesheath coverage uniformityVSAvoidextrusion instrumentation
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the sheath application process into two distinct steps: first extruding a complete uniform sheath, then selectively removing portions through piercing. This segmentation simplifies the extrusion process while achieving the desired non-uniform coverage pattern.

Inventive Principle:
Principle #1Segmentation

3Strength

If a uniform thickness covering sheath is applied onto all ropes, then mechanical stress and oscillations are reduced, but heat exchange with cooling water is impaired

Engineering Contradiction:
Improvebending strengthVSAvoidcooling efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent applies local quality by selectively removing sheath material from specific ropes that require optimal heat exchange, while maintaining complete coverage on other ropes for mechanical protection. This resolves the contradiction between structural strength and thermal efficiency.

Inventive Principle:
Principle #3Local quality

4Temperature

If the cable ropes are left uncovered, then heat exchange is optimized, but friction and mechanical wear increase significantly

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidcable lifespan
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent applies local quality by providing selective coverage: some ropes receive complete sheath protection for friction resistance, while other ropes remain exposed for heat exchange. This differentiated approach resolves the contradiction between thermal efficiency and wear protection.

Inventive Principle:
Principle #3Local quality

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 extends the cable's lifespan by reducing friction and mechanical stress, improving bending strength, and uniformly distributing electrodynamic forces, thereby reducing oscillations and shocks.

Implementation Method 1

Water runs along the entire length of the cable, entering from one terminal and exiting through the opposite one

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

cables must transfer particularly high currents and are therefore subject to considerable Joule heating

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

Applying, by extrusion, a covering sheath of uniform thickness onto all ropes making up the cable

Methodology Applied
Scientific EffectExtrusion: Extrusion

Implementation Method 4

high electric currents generate strong electromagnetic fields which cause high-intensity forces, also known as 'Lorentz force'

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP3821449B1A water-cooled electric cable and relative manufacturing method
Publication Date: 2026.01.28 BRAR ELETTROMECCANICA
  • EP3821449B1 patent drawingFigure 1~3
  • EP3821449B1 patent drawingFigure 2

AI summary

A water-cooled electric cable comprises a plurality of copper ropes (1) wound on an inner support tube (2), electric terminals (3) at the ends constrained to the ropes (1), an outer tube (4) fixed in a sealed way and a plurality of sheaths (5), one for each rope (1), which are extrusion cast in plastic or rubber material on each copper rope (1) and subsequently pierced.