Feed Water Supply for Multi-Layer Headbox Additive Dosing
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Solution Overview
Problem
Conventional paper making processes face challenges in achieving optimal bonding strength and reducing chemical consumption, as additives mixed with pulp can lead to unpredictable property changes and increased energy usage due to unclear admixture timing and reaction times.
Innovation Solution
A feed water supply system for a multi-layer headbox that separates the addition of additives and refined fibers from the stock, allowing precise control over admixture timing and distribution, using a feeding and dosing device downstream of the storage means and upstream of the pump unit to introduce cationic polymers like cationic starch and retention chemicals into the feed water, ensuring defined contact times and optimal bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additives are mixed with pulp in conventional processes, then bonding strength can be improved, but the timing of admixture becomes unpredictable and chemical consumption increases
Solution Approach 1:
The invention separates the additive mixing process into distinct stages: first mixing additives with feed water in a controlled environment, then combining this pre-mixed solution with pulp in the headbox. This segmentation allows precise control over when and how additives contact pulp fibers, resolving the timing control issue while maintaining bonding strength benefits.
Solution Approach 2:
Feed water serves as an intermediary medium that carries additives to the pulp. Instead of directly mixing additives with pulp, the system first dissolves additives in feed water, which then distributes them uniformly to the pulp in the headbox. This intermediary approach enables controlled timing and reduced chemical consumption.
2Strength
If additives are added continuously to pulp, then bonding strength improves, but chemical consumption and energy usage increase
Solution Approach 1:
The system performs preliminary mixing of additives with feed water before the pulp arrives in the headbox. This preliminary action allows complete dissolution and uniform distribution of additives in a controlled, small-volume environment, reducing the total chemical needed compared to continuous large-scale mixing with pulp.
Solution Approach 2:
The invention changes the concentration parameter by pre-diluting additives in feed water at controlled concentrations before introduction to pulp. This parameter optimization ensures effective bonding strength while minimizing chemical consumption through precise dosage control.
3Quantity of substance
If stock percentage in pulp is reduced to lower costs, then production costs decrease, but bonding strength may be compromised
Solution Approach 1:
The feed water system serves itself as both a process fluid and an additive delivery mechanism. By utilizing feed water (which is already part of the papermaking process) to carry and distribute additives, the system enhances bonding strength without requiring additional stock or chemicals, allowing cost-effective reduction of stock percentage.
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 enhances paper properties by optimizing bonding strength, reducing chemical usage, and lowering energy consumption, with improved internal bond values and tensile strength achieved through controlled addition of cationic starch and refined fibers, while maintaining cost efficiency and environmental sustainability.
Implementation Method 1
a pump unit (2), which conveys the feed water from the storage means (1)
Implementation Method 2
a feeding and dosing device, which mixes the additive with the feed water in the pipe system
Implementation Method 3
the feed water is mixed with an additive such that fiber fibrils included in the stock layers, for instance, and the additive can form a gel-like formation in the paper during web formation
Data Source
Figure 1
AI summary
A feed water supply for a multi-layer headbox of a paper machine which is capable of forming an aqueous layer is provided. Such a feed water supply comprises a storage means (1), a pump unit (2), a supply of water, and a connecting means including an inlet connector to the headbox. The storage means (1), the pump unit (2), the supply of water and the connecting means are connected with each other via pipes, and the feed water supply feeds the water to a multi-layer headbox separate from a supply of stock. The feed water supply additionally comprises a feeding and dosing device for feeding and dosing an additive into the feed water which is arranged in the feed water supply downstream of the storage means (1), between the storage means (1) and the pump unit (2).