Hollow Fiber Bundle Formation via Support Fiber Extraction
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Solution Overview
Problem
Existing methods for forming hollow fiber bundles are time-consuming and may leave trace residues of support materials or solvents, especially when the ratio of fiber diameter to bundle length is small, making them unsuitable for certain applications.
Innovation Solution
A method involving coating an elongated flexible support fiber with a hollow fiber material, creating a gap between the support fiber and the coating layer, and removing the support fiber to form hollow fibers, using techniques such as expanding the coating layer, contracting the support fiber, or using pressurized fluid to penetrate the gap, allowing for efficient extraction and reducing residue issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the dissolvable core method is used to form hollow fiber bundles, then hollow fibers can be formed with support structure, but the process becomes time-consuming when the ratio of fiber diameter to bundle length is very small
Solution Approach 1:
The invention extracts the support fiber from the coating layer by creating a gap between them, allowing the support fiber to be removed without dissolving it. This is achieved by expanding the coating layer or contracting the support fiber, enabling rapid removal without the time-consuming dissolution process while maintaining the hollow fiber structure
Solution Approach 2:
The invention changes physical parameters of either the coating layer (expansion through swelling with substances like xylene or toluene) or the support fiber (contraction through cooling or stretching) to create a gap. This parameter change enables the support fiber to be extracted quickly without dissolution, resolving the time-consuming issue while preserving manufacturing precision
2Manufacturing precision
If the dissolvable core method is used, then hollow fibers can be formed, but trace residues of support material or solvent remain in the resulting hollow fibers
Solution Approach 1:
Instead of dissolving the support fiber which leaves residues, the invention extracts it intact by creating a gap through expansion or contraction. This mechanical extraction eliminates trace residues of both support material and solvent, while still achieving hollow fiber formation with the desired precision
Solution Approach 2:
The support fiber serves as a temporary, disposable structure that is removed after serving its purpose during coating. By extracting it mechanically rather than dissolving it, the invention eliminates harmful residues while the support fiber itself is discarded after use
3Ease of operation
If the coating layer is expanded or support fiber contracted to create a gap, then support fiber removal is facilitated, but additional processing steps are required
Solution Approach 1:
The invention uses parameter changes (thermal expansion/contraction, chemical swelling) to create the gap, which are straightforward physical or chemical processes that add minimal complexity while dramatically improving ease of support fiber removal
Solution Approach 2:
The invention exploits thermal expansion and contraction properties of materials. By heating or cooling the support fiber or coating layer, a gap is created that facilitates easy removal, adding only a simple thermal processing step rather than complex mechanical systems
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 method enables the efficient formation of hollow fiber bundles with minimal residue and improved processing speed, suitable for applications requiring small diameters and long lengths, by creating a gap between the support fiber and the coating layer to facilitate removal.
Implementation Method 1
The gap creating step comprises expanding the cured coating layer by swelling the cured coating layer by exposing it to a substance operable to swell the cured coating layer, thereby increasing an inner dimension of the coating layer
Implementation Method 2
One contracting method includes providing a support fiber with an outer dimension that expands with temperature, the support fiber being at a first temperature during coating with the hollow fiber material and the support fiber being at a second lower temperature for creation of the gap. This method further comprises cooling the support fiber from the first temperature to the second temperature
Implementation Method 3
using a pressurized fluid to penetrate between the outer surface of the support fiber and the inner surface of the coating layer
Data Source
AI summary
A method of forming a plurality of hollow fibers includes the step of providing an elongated flexible substantially continuous fiber and coating an outer surface of the fiber with a hollow fiber material. The hollow fiber material is cured or hardened. A gap is created between the outer surface of the support fiber and the inner surface of the coating layer defined thereon. The coated support fiber is cut into a plurality of fiber segments each having exposed ends. The support fiber segments are removed from the coating layer so as to provide a plurality of hollow fibers.