Rotatable Slat Screen for Uniform Fiber Distribution

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Solution Overview

Problem

Existing forming boxes for dry-forming mats of fibrous material lack effective control over the distribution of fibrous material across the forming wire, leading to uneven mat formation.

Innovation Solution

A forming box equipped with a screen comprising rotatable slats that generate turbulence to control the flow and distribution of fibrous material, allowing for adjustable positioning and rotation of slats to direct fibers uniformly across the forming wire, along with multiple rows of spike rollers for disintegration and mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional forming box without turbulence-generating elements is used, then the structure is simple, but the distribution of fibrous material over the forming wire is uneven

Engineering Contradiction:
Improvedistribution uniformityVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The slats are made rotatable to dynamically generate turbulence in the air stream carrying fibrous material. This turbulence randomizes the fiber trajectories and improves distribution uniformity across the forming wire, resolving the contradiction between simple structure and poor distribution control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rotational speed of the slats is adjusted as a controllable parameter to optimize turbulence intensity. By varying the rotation speed, the system adapts to different fibrous material types and flow rates, achieving uniform distribution without requiring complex mechanical structures

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the slats are positioned at a fixed angle, then the structure is simple, but the control over material distribution is limited

Engineering Contradiction:
Improvedistribution controlVSAvoidslat mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The slats transition from fixed to rotatable, enabling dynamic control of turbulence and fiber distribution. This mechanical simplicity (single rotation degree of freedom) provides operational flexibility for different material types without complex control systems

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rotatable slat mechanism serves multiple functions: generating turbulence, directing fiber flow, and adapting to different material properties. This multi-functionality achieves ease of operation across various applications without increasing structural complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If the slats rotate continuously, then the turbulence is maximized for better distribution, but the energy consumption increases

Engineering Contradiction:
Improvefiber distribution controlVSAvoidslat rotation energy
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

Instead of continuous rotation, the slats can rotate periodically or intermittently to generate sufficient turbulence for uniform distribution. This periodic action reduces energy consumption while maintaining the turbulence effect needed for fiber distribution control

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The slats rotate only to the extent necessary to generate adequate turbulence for distribution, rather than continuous high-speed rotation. This partial action achieves the required distribution precision with minimized energy input

Inventive Principle:
Principle #16Partial or excessive action

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 solution ensures a controlled and uniform distribution of fibrous material, enabling the production of mats with desired patterns and quality, while also self-cleaning the slats and accommodating different types of fibers and granulates.

Implementation Method 1

a vacuum box underneath said forming wire

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

As fibres enter the forming box they are sucked towards the forming wire

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 3

By use of a screen comprising a plurality of slats it is possible to generate turbulence, which slows down the flow of fibres from the inlet to the forming wire

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 4

a number of spike rollers are provided in at least one row in the housing between the fibre inlet and the housing bottom

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2992129B1A method and apparatus for dry-forming a fibrous product
Publication Date: 2018.08.15 FORMFIBER DENMARK APS
  • EP2992129B1 patent drawingFigure 1
  • EP2992129B1 patent drawingFigure 2~3
  • EP2992129B1 patent drawingFigure 4

AI summary

The invention regards a forming box for use in dry-forming a mat of fibrous material, said forming box comprising a housing with an open bottom for providing direct access of the fibres onto an underlying forming wire and a vacuum box underneath said forming wire,at least one inlet for supplying fibre material into the inside of the housing, a number of spike rollers are provided in at least one row in the housing between the fibre inlet and the housing bottom,wherein a screen is provided adjacent said spike rollers, said screen comprising a plurality of slats, wherein each slat is rotatable.