Dry Core Optical Cable Water-Blocking Plugs
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Solution Overview
Problem
Current optical fiber cables face challenges in effectively blocking water migration, especially in high ionic concentration environments, while maintaining strong coupling between optical fibers and buffer tubes, and avoiding the drawbacks of existing water-blocking methods such as thixotropic gels and super absorbent powders, which can lead to attenuation and manufacturing complexities.
Innovation Solution
The use of water-blocking plugs made from a solid filling material, such as rubberized hydrocarbons or foamed polymeric materials, that provide a firmer yet deformable coupling, allowing for higher pullout forces without causing stress to the optical fibers and reducing attenuation, while being easier to manufacture and cleaner to access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thixotropic gel is used as filling compound to block water migration, then water-blocking capability is improved, but fiber coupling strength deteriorates and cleanup complexity increases
Solution Approach 1:
The patent changes the physical state parameter of the filling compound from gel (semi-solid) to solid material, fundamentally altering its properties. This enables the material to provide both water-blocking capability and strong fiber coupling without the cleanup issues of gels, as the solid material remains stable and does not require removal like gel does
Solution Approach 2:
The patent employs composite materials combining solid filling material with specific properties (firmness, deformability, water-blocking capability). This composite approach allows the material to simultaneously achieve water blocking, strong fiber coupling (greater than 5 N/m pullout force), and ease of operation without the drawbacks of pure gel or simple powder formulations
2Reliability
If super absorbent powder (SAP) is used to block water migration, then water-blocking capability is improved, but fiber coupling strength deteriorates
Solution Approach 1:
The patent changes the mechanical property parameters of the filling material, specifically increasing firmness while maintaining deformability. The solid filling material provides a normalized pullout force greater than 5 N/m, significantly improving fiber coupling strength compared to SAP while retaining water-blocking capability through its solid structure and deformable nature
3Reliability
If water-blocking plugs are used to block water migration, then water-blocking capability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the buffer tube into multiple segments with water-blocking plugs positioned at intervals along the tube. This segmentation approach provides effective water blocking at discrete locations while simplifying manufacturing compared to continuous filling methods, as plugs can be inserted at regular intervals during the extrusion process
Solution Approach 2:
The water-blocking plugs are pre-formed and pre-positioned within the buffer tube during the extrusion process. This preliminary preparation of the filling material and its placement simplifies manufacturing by integrating the water-blocking function into the tube formation process itself, rather than requiring separate complex assembly steps
4Force
If firm filling material is used to increase pullout force, then fiber coupling strength is improved, but risk of fiber stress and attenuation increases
Solution Approach 1:
The patent optimizes the mechanical property parameters of the solid filling material, specifically balancing firmness and deformability. The material is formulated to be firm enough to provide strong coupling (greater than 5 N/m pullout force) while remaining deformable enough to accommodate fiber movements without causing stress or attenuation, achieving an optimal parameter range
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 achieves a pullout force greater than 5 N/m with reduced attenuation and microbending effects, enabling effective water-blocking and thermal stability, while simplifying the manufacturing process and minimizing mess during fiber access.
Implementation Method 1
The use of water-blocking plugs made from a solid filling material, such as rubberized hydrocarbons or foamed polymeric materials, that provide a firmer yet deformable coupling
Implementation Method 2
The compounds used for blocking water migration within a fiber optic cable generally separate into two classifications: (1) 'filling' compounds and (2) 'flooding' compounds
Data Source
AI summary
An optical fiber cable includes at least one buffer tube that includes a plurality of water-blocking plugs and an optical fiber. The water-blocking plugs can be spaced along the buffer tubes, substantially filling the cross-sectional space within the buffer tube not already filled by the optical fiber. The water-blocking plugs can provide a stronger bond between the optical fibers and the inner tube. This is reflected by a high normalized pullout force for the optical fiber, such as, above 5.0 N/m. Yet, the resulting fiber optic cable does not suffer from problems associated with a higher pullout force, such as attenuation.