Optical Fiber Coating for Armored Cable Friction Reduction
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Solution Overview
Problem
The existing methods for manufacturing armoured cables with optical fibres are costly and time-consuming, particularly when inserting fibres into guide tubes, as they often require an inner tube for protection, which increases costs and makes it difficult to achieve a desired excess fibre length (EFL) and control fibre friction and static charge during the welding process.
Innovation Solution
A system and method that involves coating optical fibres with a lubricating coating, such as graphite, molybdenum disulphide, or boron nitrite, to reduce friction and static charge, and inserting them directly into a guide tube during the seam welding process of the armour tube, without using an inner tube, allowing for controlled excess fibre length by adjusting the fibre feed rate relative to the armour tube welding speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an inner tube is used to protect optical fibres during welding, then fibre protection from heat is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the inner tube from the final cable structure, extracting only the essential protective function needed during welding. The guide tube provides temporary protection during the welding process, then is removed, leaving a simpler two-layer structure (armour tube and outer sheath) without the costly inner tube.
Solution Approach 2:
The optical fibres are pre-coated with a friction-reducing material before insertion into the guide tube. This preliminary action reduces friction during the pushing process and prevents static charge buildup, eliminating the need for additional inner tube protection while ensuring fibre integrity during welding.
2Ease of operation
If optical fibres are pushed into guide tubes using gas or liquids, then fibre insertion is achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent replaces complex pneumatic or liquid-based insertion systems with a simple mechanical pushing mechanism. The fibres are pushed directly into the guide tubes using mechanical force, eliminating the need for gas or liquid media and significantly reducing manufacturing time and complexity.
Solution Approach 2:
The patent changes the surface properties of the optical fibres by applying a friction-reducing coating. This parameter change reduces the coefficient of friction between the fibre and guide tube, allowing easy mechanical insertion without requiring gas or liquid assistance, thereby improving productivity.
3Manufacturing precision
If optical fibres are pulled through guide tubes during welding, then fibre positioning is achieved, but friction and static charge increase
Solution Approach 1:
The patent applies a friction-reducing coating to the optical fibres, changing the surface parameters to reduce the coefficient of friction. This allows the fibres to be pulled through the guide tubes with minimal friction and static charge generation, while still achieving precise positioning control during the welding process.
Solution Approach 2:
The friction-reducing coating acts as an intermediary substance between the optical fibre and the guide tube. This intermediate layer reduces direct contact friction and prevents static charge buildup, enabling smooth fibre movement through the guide tube while maintaining manufacturing precision.
4Length of moving object
If excess fibre length is achieved by pulling fibres through guide tubes, then EFL is obtained, but control precision is difficult
Solution Approach 1:
The patent implements a feedback control system that monitors the fibre feed rate and adjusts it to maintain the desired excess fibre length. The controller receives information about the welding speed and fibre consumption, then dynamically adjusts the fibre feed rate to achieve precise EFL control, overcoming the difficulties of manual or open-loop methods.
Solution Approach 2:
The patent transitions from a static fibre insertion method to a dynamic controlled feed system. The fibre feed rate is dynamically adjusted during the welding process based on real-time conditions, allowing precise control of excess fibre length while accommodating variations in welding speed and fibre consumption rates.
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
This approach reduces the cost and complexity of manufacturing armoured cables by eliminating the need for an inner tube, enabling precise control of EFL and minimizing fibre damage from heat and friction, while ensuring uniform fibre distribution and reducing static charge during the welding process.
Implementation Method 1
a coating configured to reduce friction between the at least one optical fibre and the at least one guide tube during an insertion operation
Implementation Method 2
a coating configured to reduce friction and static charge when inserting the one or more optical fibres in one or more guide tubes
Data Source
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AI summary
A system for making an armoured cable, comprising: a tube-forming device (114) configured to seam weld an armour tubing of the armoured cable; at least one guide tube (108) disposed in a welding zone (110) in which a seam of the armour tubing is welded, the at least one guide tube positioned to protect at least one optical fibre (102) during welding of the seam, but is not part of the armoured cable after the making; and a coating device (116) configured to coat the at least one optical fibre with a coating, wherein the coating is configured to reduce friction between the at least one optical fibre and the at least one guide tube during an insertion operation. The present disclosure also includes a method for making an armoured cable.