Spunbond Nonwoven Filament Cooling via Zone Segmentation
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Solution Overview
Problem
Existing methods for producing spunbond non-woven fabrics face inefficiencies in filament cooling, particularly due to the accumulation of heat in central cooling elements, which affects cooling efficiency and leads to suboptimal filament stretching and production rates.
Innovation Solution
A process and apparatus that extrude filaments into two bundles separated by a space, with cooling air passing through twice, initially heating and then cooling the filaments, and using angled air flows and suction outlets to optimize thermal gradients and maintain pneumatic separation between the cooling and stretching areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a central conical element is used in the cooling chamber to cool filaments, then the filaments are cooled, but the conical element accumulates heat and negatively affects cooling efficiency
Solution Approach 1:
The patent removes the central conical element from the cooling chamber to eliminate the source of heat accumulation. By extracting this problematic component, the cooling air can flow freely through the chamber without being obstructed by a heat-absorbing structure, thereby resolving the contradiction between cooling efficiency and energy loss.
Solution Approach 2:
The cooling chamber is divided into multiple zones with different cooling intensities. The chamber includes a first cooling zone with higher cooling intensity near the spinneret and a second cooling zone with lower cooling intensity further downstream. This segmentation allows optimized cooling at different stages without requiring a central heat-absorbing element.
2Temperature
If cooling air flows are increased to improve filament cooling, then cooling efficiency improves, but pneumatic separation between cooling and stretching areas is compromised
Solution Approach 1:
Different regions of the cooling chamber are assigned different cooling characteristics. The first cooling zone near the spinneret provides intense cooling with higher air flow, while the second cooling zone downstream provides gentler cooling. This local differentiation allows effective cooling without disrupting the pneumatic separation needed for subsequent stretching operations.
Solution Approach 2:
The cooling air flow is made dynamic by introducing it at an angle (30-60 degrees) relative to the filament bundle axis. This angled introduction creates a controlled flow pattern that provides effective cooling while maintaining the pneumatic separation between the cooling and stretching zones, allowing the system to adapt to different operating conditions.
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 enables gradual and uniform cooling, allowing for finer filament counts and increased production rates, up to 30% higher throughput, while maintaining high filament quality for applications like medical filters and masks.
Implementation Method 1
Air is fed into said chamber to partially cool the filaments extruded by the spinneret
Implementation Method 2
cooling air flows are superimposed vertically with the upper flow having a higher temperature than the lower flow
Implementation Method 3
the filaments are solidified to such a degree that they can be stretched to the required dimensions in the subsequent step of exposure to high-speed air
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
In an apparatus for the production of a non-woven fabric, a plurality of filaments (11) are extruded by a spinneret (2) into at least two groups spaced from each other to define an area of the cooling chamber without filaments and structures; the filaments are cooled by an air flow (Y) conveyed into the cooling chamber directed towards an intermediate area between said two groups of filaments, said area being located below an area of the spinneret without extrusion holes.