Cable Core Extraction via Resistive Heating
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Solution Overview
Problem
The existing methods for replacing cable cores with optical fibers or hybrid cores are disruptive, time-consuming, and expensive, as they require digging trenches and often damage the outer sheath, making it difficult to extract the copper core without high pressure, which can damage the sheath and prevent re-use.
Innovation Solution
A method involving resistive heating of the cable core by supplying electric current to reduce the viscosity of the surrounding filler material, allowing the core to be easily pulled out of the sheath without damaging it, and an apparatus with an electrical generator and draw-string mechanism to facilitate this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pressure is applied to extract the cable core from the sheath, then the core can be removed, but the outer sheath is damaged and cannot be re-used
Solution Approach 1:
The invention changes the physical state of the filler material by heating it to a temperature where its viscosity decreases significantly. This parameter change (from solid/semi-solid to softened state) allows the cable core to be extracted with reduced force, preventing damage to the outer sheath and enabling its re-use.
Solution Approach 2:
The filler material undergoes a phase transition or significant viscosity change when heated. By raising the temperature above a threshold, the filler material transitions from a rigid state that grips the core to a softened, more fluid state that allows easy core removal without damaging the sheath structure.
2Reliability
If the cable core is extracted without heating the filler material, then the sheath is preserved, but extremely high force is required that damages the sheath
Solution Approach 1:
By changing the temperature parameter of the filler material, the invention reduces the extraction force required. The heated filler material becomes less viscous and provides less frictional resistance, allowing core extraction with forces that do not damage the outer sheath.
3Productivity
If traditional trenching methods are used to replace cables, then new optical fibre cables can be installed, but the process is disruptive, time-consuming and expensive
Solution Approach 1:
The invention recovers and re-uses the existing outer sheath structure after removing the old cable core. By preserving the sheath and simply inserting a new core through the vacated space, the method eliminates the need for trenching and complete cable replacement, significantly reducing installation time and disruption.
Solution Approach 2:
The invention extracts only the cable core from the existing sheath structure, leaving the sheath intact. This selective extraction allows the sheath to be re-used for the new core, avoiding the need to remove and replace the entire cable assembly through trenching operations.
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
Enables efficient extraction of the cable core with reduced force, preserving the outer sheath for re-use and simplifying the process by using the heated filler material as a lubricant, allowing for manual or mechanical removal with lower tensile forces than the core's strength, and subsequent flushing to prepare for new core insertion.
Implementation Method 1
resistively heating the core by supplying electric current to it
Implementation Method 2
using the heated filler material as a lubricant
Data Source
AI summary
A method of removing a metallic cable core that extends through an outer cable sheath of a length of data transmission cable is disclosed. The core is surrounded by a filler material contained within the outer cable sheath as an integral part of the cable. The method comprises the steps of resistively heating the core by supplying electric current to it to reduce the viscosity of the surrounding polymer material; and pulling the core out of one end of the outer cable sheath while the viscosity of the filler material is in a reduced state.