Non-woven Fabric Diffusing Unit Airflow Control
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Solution Overview
Problem
Non-woven fabrics with high uniformity often suffer from insufficient filament entanglement, leading to reduced strength.
Innovation Solution
An apparatus and method that include a diffusing unit with a main nozzle and a diffusion space where air is jetted with filaments, and an air flow generation means to create a follow-up air flow that reduces flow velocity fluctuations, enhancing filament diffusion and entanglement, thereby improving uniformity while maintaining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high uniformity is achieved in non-woven fabric, then mesh size uniformity is improved, but filament entanglement becomes insufficient leading to reduced strength
Solution Approach 1:
The air flow is segmented into multiple controlled streams through the diffusing unit design. The main nozzle emits air that flows along the collecting medium surface, while additional air is introduced through side openings to create localized flow zones. This segmentation allows precise control over filament diffusion and entanglement in different regions, achieving both uniformity and strength.
Solution Approach 2:
The invention changes the parameters of air flow by controlling the flow rate, velocity distribution, and pressure through the diffusing unit. By adjusting these air flow parameters, the system optimizes the balance between filament diffusion (for uniformity) and filament entanglement (for strength), resolving the technical contradiction.
2Manufacturing precision
If air flow velocity is increased to enhance filament diffusion, then uniformity is improved, but flow velocity fluctuations increase causing instability in filament deposition
Solution Approach 1:
The diffusing unit acts as an intermediary between the air source and the collecting medium. It mediates the air flow by distributing it uniformly across the width of the collecting medium and controlling the velocity profile. This intermediary structure smooths out flow velocity fluctuations while maintaining high diffusion capability, preventing direct transmission of unstable flow to the filament deposition process.
Solution Approach 2:
The air flow is pre-conditioned in the diffusing unit before reaching the collecting medium. The side openings introduce air that merges with the main air stream in advance, creating a stabilized composite flow with reduced velocity fluctuations. This preliminary action ensures that by the time air reaches the filaments, the flow is both fast enough for good diffusion and stable enough for consistent deposition.
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 results in a non-woven fabric with improved uniformity and suppressed strength deterioration, achieving a strength ratio of 5% elongation in the machine direction to 5% elongation perpendicular to the machine direction of 2.0 or less and a maximum strength of 35.0 N/25 mm or more.
Implementation Method 1
a main nozzle that jets, toward the collecting medium, air that is supplied together with the filaments
Implementation Method 2
a diffusion space that is provided between the main nozzle and the collecting medium and in which the filaments are diffused by an air flow
Implementation Method 3
an air flow generation means that generates, around the air flow of the air jetted from the main nozzle into the diffusion space, an air flow that is close to and follows the air flow
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A diffusing unit of an apparatus for manufacturing a non-woven fabric is provided with a diffusion space between a jet nozzle and a moving belt of a collecting unit, an opening of a sub nozzle is arranged side-by-side with an opening of the jet nozzle, and the sub nozzle jets air from the opening. The jet nozzle jets, toward the moving belt, plural filaments together with air. The air jetted from the jet nozzle forms a conveying flow that gradually spreads and flows in the diffusion space, and the plural filaments are diffused by this conveying flow and are sent toward the moving belt to be collected. The air jetted from the sub nozzle flows along the air flow around the conveying flow and suppresses air in the diffusion space from entering the conveying flow.