Narrow Strip Dewatering Element for Uniform Pressure

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Solution Overview

Problem

Existing dewatering elements in web-forming machines face inefficiencies in dewatering capacity and pulsating pressure issues, with wide strips and slots leading to uneven water removal and structural durability challenges, and the complexity of manufacturing oblique holes for enhanced water flow.

Innovation Solution

A dewatering element with narrow, cross-machine directional strips and matching narrow openings, forming a straight or curvilinear surface, which supports uniform non-pulsating dewatering pressure and is manufactured from steel for durability and cost-effectiveness, utilizing underpressure for controlled water removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If wide strips are used in the dewatering element, then the structural strength and durability are improved, but the dewatering efficiency decreases and pulsating pressure issues occur

Engineering Contradiction:
Improvestructural strengthVSAvoiddewatering efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The cover is segmented into multiple narrow strips (each less than 10mm wide) spaced closely together, creating numerous small openings for water removal. This segmentation allows uniform pressure distribution across the web while maintaining high dewatering capacity through the combined effect of many small openings, eliminating the pulsating pressure problems associated with wide strips.

Inventive Principle:
Principle #1Segmentation

2Productivity

If oblique holes are bored in the cover to intensify water flow, then the dewatering capacity is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improvedewatering capacityVSAvoidmanufacturing complexity
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

Instead of boring holes obliquely through the cover at an angle to intensify water flow (which requires special tools and expertise), the invention uses narrow strips arranged in the machine direction with openings between them. This inverted approach achieves enhanced water removal through the combined effect of numerous closely-spaced openings, eliminating the need for complex oblique hole boring while maintaining high dewatering capacity.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If narrow strips with narrow openings are used, then the dewatering efficiency and pressure uniformity are improved, but the structural strength may be compromised

Engineering Contradiction:
Improvedewatering efficiencyVSAvoidstructural strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The narrow strips are provided with increased thickness specifically at their lower surfaces (the side contacting the web), creating local reinforcement where it is most needed for structural strength. The upper surfaces maintain the narrow width necessary for efficient dewatering. This local quality variation allows the strips to provide both high dewatering efficiency through their narrow geometry and adequate structural strength through targeted thickening.

Inventive Principle:
Principle #3Local quality

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 enhances dewatering efficiency by maintaining uniform pressure and reducing water volume disturbances, allowing for lower pulp consistency and improved web formation with reduced structural stress and manufacturing costs.

Implementation Method 1

Underpressure arranged below the cover can further intensify the dewatering of the web

Methodology Applied
Scientific EffectUnderpressure: Depressurisation

Data Source

PatentEP2408963B1Dewatering element for web-forming machine
Publication Date: 2019.06.05 VALMET TECH INC
  • EP2408963B1 patent drawingFigure 1
  • EP2408963B1 patent drawingFigure 2~3
  • EP2408963B1 patent drawingFigure 4~5

AI summary

A dewatering element (100) comprises a straight or curvilinear cover (110) coming against the fabric, which cover includes a leading edge (111) and a trailing edge (112) and between them a section with holes consisting of cross-machine directional strips (120) being at a distance from each other in the machine direction (S), between which strips there are openings (130). A width (A) of the strips (120) in the machine direction (S) is less than 10 mm, advantageously 2-8 mm, and a width (B) of the openings (130) between the strips (120) in the machine direction (S) is less than 10 mm, advantageously 3-8 mm.