Fibrous Web Free-Draw Transfer With Edge Air Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The transfer of a wet and unbonded fibrous material web from a binder wire to a dryer fabric in a free draw is prone to creasing and breakage due to turbulent airflows, especially at high speeds and low web weights, leading to production losses and poor runability.
Innovation Solution
The implementation of edge-side air extraction devices at the transfer region between the binder wire and dryer sections to stabilize airflow, using suction boxes connected to negative pressure sources, which are positioned predominantly underneath the web to avoid contamination and maintenance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fibrous material web is transferred in a free draw from binder wire to dryer fabric, then the web can be transferred without contact contamination, but turbulent airflows cause creasing and breakage especially at high speeds and low web weights
Solution Approach 1:
A controlled airflow field is introduced as an intermediary medium between the binder wire and dryer fabric to stabilize the web during transfer. The airflow acts as a cushion that prevents direct contact while eliminating turbulent fluctuations that cause creasing, enabling reliable transfer of lightweight webs at high speeds without contamination or damage
Solution Approach 2:
The airflow parameters (velocity, pressure, direction) are precisely controlled and optimized to match the web weight and transfer speed. By dynamically adjusting these parameters, the system maintains stable web support conditions across varying operating conditions, preventing creasing and breakage while preserving the contactless transfer benefit
2Reliability
If a transfer roll is used to transfer the web, then the transfer is mechanically stable, but the roll surface is quickly contaminated with glass fibers causing production loss and poor runability
Solution Approach 1:
The mechanical contact-based transfer roll system is replaced with a pneumatic field-based transfer system. Instead of using a physical roll that contacts and collects the web, a controlled airflow field performs the transfer function, eliminating the mechanical component that would become contaminated and cause production losses
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
Stabilizes airflow to prevent creasing and breakage of the fibrous material web, ensuring reliable operation at high speeds and low web weights without compromising runability.
Implementation Method 1
at least one air extraction device is arranged at the edge of the installation in the region of the distance between the binder wire section and the dryer section
Data Source
AI summary
An installation for producing a fibrous material web, in particular a long-fiber paper or wet nonwoven web, contains a binder wire section having a binder wire for applying an aqueous binder to the fibrous material web, and a dryer section having a dryer fabric for drying and consolidating the fibrous material web. The binder wire section and the dryer section are arranged at a distance from each other, so that the fibrous material web is led from the binder wire to the dryer fabric in a free draw. At least one air extraction device is arranged at the edge of the installation in the region of the distance between the binder wire section and the dryer section.