Flow Straightener Geometry for Uniform Cooling in Spunbonded Nonwoven Production
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Solution Overview
Problem
Existing apparatuses for producing spunbonded nonwovens from continuous filaments often result in inhomogeneous products with imperfections, such as 'drops' and 'hard pieces,' which increase with higher throughputs and yarn speeds, leading to defective nonwovens.
Innovation Solution
The apparatus incorporates a flow straightener with a high flow cross section and specific passage geometry in the air-supply manifolds to ensure uniform cooling air distribution, preventing filament defects by optimizing the cooling air flow and incidence on the filaments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If throughput and yarn speed are increased to improve productivity, then production efficiency is improved, but the number of inhomogeneities and defects in the spunbonded nonwoven increases
Solution Approach 1:
The patent changes the geometric parameters of the flow straightener (passage cross-section greater than 85% of straightener cross-section, L/Di ratio between 1-15) to optimize cooling air flow characteristics. These parameter changes enable uniform cooling air distribution even at high throughput and yarn speeds, preventing defects while maintaining high productivity
Solution Approach 2:
The flow straightener acts as an intermediary device between the cooling air supply and the filaments. It mediates the cooling air flow by straightening and equalizing it before the air reaches the filaments, ensuring uniform cooling that prevents inhomogeneities and defects during high-speed production
2Ease of operation
If conventional flow straighteners are used in the air-supply manifolds, then cooling air is supplied to the cooling chamber, but the cooling air flow is not uniform resulting in inhomogeneities and defects
Solution Approach 1:
The patent specifies critical geometric parameters for the flow straightener: passage cross-section greater than 85% of the straightener cross-section and L/Di ratio between 1-15. These parameter changes create optimal flow conditions that ensure uniform cooling air distribution across the cooling chamber, eliminating inhomogeneities while maintaining ease of operation
Solution Approach 2:
The flow straightener is segmented into multiple flow passages arranged in a grid pattern. This segmentation divides the cooling air flow into numerous small, uniform streams that collectively provide even distribution across the cooling chamber, preventing localized inhomogeneities and defects
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 configuration produces highly homogeneous spunbonded nonwovens with minimal imperfections, even at high throughputs and yarn speeds, ensuring optimal quality and cost-effectiveness.
Implementation Method 1
A flow straightener for equalizing flow of the cooling air on the filaments is provided in at least one of the air-supply manifolds and has passage walls forming a plurality of flow passages that extend transversely to a filament-travel direction
Implementation Method 2
a cooling chamber for cooling the spun filaments with cooling air, and two air-supply manifolds flanking the chamber for feeding cooling air thereinto transverse to the direction
Data Source
AI summary
An apparatus for making spunbonded nonwoven has a spinneret for emitting the continuous filaments in a filament-travel direction, a cooling chamber downstream in the direction from the spinneret and receiving the filaments, and two air-supply manifolds flanking the chamber for feeding cooling air thereinto transverse to the direction. A flow straightener for equalizing flow of the cooling air on the filaments is provided in at least one of the air-supply manifolds and has passage walls forming a plurality of flow passages that extend transversely to a filament-travel direction. A flow cross section of the flow straightener is greater than 85% (preferably more than 90%) of a cross-sectional size of the straightener, a ratio of a length L of the flow passages to an inner diameter Di of the flow passages L/Di is 1 to 15.