Airfoil With Perpendicular Airflow For Web Flutter Control

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Solution Overview

Problem

Web flutter and damage occur during the transportation of fragile tissue paper or non-woven fibrous material through the draw between the drying and winding areas in tissue paper manufacturing, due to airflow instabilities and physical contact with mechanical parts, which worsens at higher production speeds.

Innovation Solution

The use of airfoils with multiple conduits and strategically oriented slots or holes that direct air perpendicular to the web movement, utilizing the Coanda effect to create areas of low pressure and stabilize the web, reducing physical contact and fluttering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If rigid pipes or rolls are used to control web movement, then web stability is improved, but fiber breakage and dust generation increase

Engineering Contradiction:

Improveweb stabilityVSAvoidfiber breakage and dust

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent replaces rigid mechanical contact systems (pipes and rolls) with an aerodynamic field-based system. Airfoils generate controlled airflow fields that interact with the web through fluid dynamics rather than direct mechanical contact, eliminating fiber breakage while maintaining web stability through aerodynamic forces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes pneumatic principles by employing airfoils that generate controlled airflow to stabilize and transport the web. The airfoil design creates pressure differentials and airflow patterns that hold and guide the web without mechanical contact, replacing solid mechanical systems with a pneumatic field-based approach.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Object-affected harmful factors

If airfoils with parallel airflow are used, then web contact is reduced, but web flutter increases at higher speeds

Engineering Contradiction:

Improveweb contactVSAvoidweb flutter

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent introduces perpendicular airflow components that act in a direction normal to the web surface, complementing the parallel airflow. This dimensional addition creates a three-dimensional airflow field that provides both support (reducing contact) and stabilization (reducing flutter) simultaneously, rather than relying solely on one-dimensional parallel flow.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent implements different airflow directions at different locations and orientations. The airfoil structure generates both parallel airflow (for reduced contact) and perpendicular airflow components (for stabilization), creating locally optimized flow patterns that address different aspects of web control in different spatial zones.

Inventive Principle:

Principle #3Local quality

3Productivity

If production speed is increased, then productivity is improved, but web flutter and damage worsen

Engineering Contradiction:

Improveproduction speedVSAvoidweb flutter

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The airfoil-based pneumatic system provides dynamic control capability that adapts to higher speeds. The aerodynamic forces generated by the airfoils scale with airflow velocity, allowing the system to maintain effective web control and stability even as production speed increases, unlike static mechanical systems that become inadequate at higher velocities.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 effectively stabilizes the web by minimizing contact with mechanical parts and reducing fluttering, enhancing web quality and reducing dust generation, while allowing for higher production speeds without web damage.

Implementation Method 1

utilizing the Coanda effect to create areas of low pressure and stabilize the web

Methodology Applied

Scientific EffectCoanda effect: Coanda Effect

Implementation Method 2

Airfoils generally create lift by exploiting the Bernoulli Principal

Methodology Applied

Scientific EffectBernoulli principle: Bernoulli Effect

Data Source

PatentUS10287124B2Airfoil with perpendicular airflow

Publication Date: 2019.05.14 ANDRITZ AG

AI summary

The problem of web flutter experienced by webs spanning the draw between a drying area of a fiber web manufacturing machine and winder, wherein the web is assisted by airfoils is mitigated by using at least one airfoil having multiple conduits connected to at least one air supply, at least two areas with openings in form of slots or rows of holes (or elongated openings) are oriented a direction substantially parallel to the direction of web movement, wherein the openings communicate with the multiple conduits, a Coanda surface disposed adjacent to the openings, and wherein the openings are configured to direct air flowing from the air source through the multiple conduits, through the openings over the Coanda surface in a direction substantially perpendicular to the direction of web movement.