Fiber Web Feed System Foam Density Control

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Solution Overview

Problem

Existing fiber web machine feed systems lack precise control over foam generation agents, leading to inconsistent web formation and end product properties due to inadequate measurement and control of stock density before and after foam generation.

Innovation Solution

Incorporating measuring equipment in the feed line before and after foam generation equipment to determine stock density, allowing for controlled adjustment of agents affecting foam generation, thereby optimizing foam formation and product properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If foam generation equipment is used to feed agents into the stock, then web formation and end product properties can be improved, but precise control over agent dosage is lost leading to inconsistent quality

Engineering Contradiction:
Improveweb formation consistencyVSAvoidagent dosage control
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent implements a feedback control system where density measurements are continuously taken before and after foam generation equipment, and the control system adjusts agent dosage based on the measured density changes. This closed-loop feedback mechanism ensures precise control over foam generation while maintaining consistent web formation quality.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent monitors and controls the density parameter of the stock before and after foam generation to indirectly control the amount of agents added. By maintaining density within specific ranges, the system achieves precise agent dosage control without direct measurement of agent quantities.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If measuring equipment is installed in the feed line before foam generation, then agent dosage can be optimized, but the system complexity increases

Engineering Contradiction:
Improveagent dosage optimizationVSAvoidmeasurement system complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent uses density measurement as an intermediary parameter to control agent dosage indirectly. Instead of directly measuring agent quantities or foam properties, the system measures stock density before and after foam generation, which serves as a proxy indicator for agent concentration and foam formation effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If density measurement is performed both before and after foam generation, then foam generation can be precisely controlled, but the number of measuring devices increases

Engineering Contradiction:
Improvefoam generation control precisionVSAvoidnumber of measuring devices
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs feedback control using density measurements taken at multiple points in the feed line. By comparing density values before and after foam generation equipment, the system determines the effectiveness of agent addition and adjusts subsequent dosing accordingly, achieving precise control through information feedback rather than simply increasing measurement frequency.

Inventive Principle:
Principle #23Feedback

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 approach enables precise control over foam generation, improving web formation and reducing agent usage by allowing for purposeful dosing based on real-time density measurements, ensuring consistent end product quality.

Implementation Method 1

measuring equipment for determining the density of the stock, adapted in the feed line before and after the foam generation equipment

Methodology Applied
Scientific EffectRadiation attenuation: Absorption (EM radiation)

Data Source

PatentEP3162956B1Feed system of a fiber web machine
Publication Date: 2019.03.13 VALMET TECH OY
  • EP3162956B1 patent drawingFigure 1
  • EP3162956B1 patent drawingFigure 2
  • EP3162956B1 patent drawingFigure 3

AI summary

The invention relates to a feed system of a fiber web machine, which feed system includes a feed line (12) for taking stock (31) towards a headbox (10) of a fiber web machine, and foam generation equipment (13) adapted in the feed line for the feeding of one or more agents (41) into the stock for foam forming. The feed system further includes measuring equipment (15.1, 15.2) for determining the density of the stock (31, 32, 33), adapted in the feed line before and after the foam generation equipment, and control equipment (16), which has been adapted, on the basis of said determination of density, to control the foam generation equipment for the feeding of one or more agents into the stock for foam forming.