Multilayer Headbox Blades Separate Liquid Layers
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Solution Overview
Problem
Existing multilayer headbox structures for fiber web machines fail to maintain the purity and consistency of individual liquid layers due to turbulence, leading to unwanted mixing and chemical reactions that degrade the quality of the fiber web.
Innovation Solution
A multilayer headbox structure with a turbulence generator and nozzle chamber featuring converging walls and diffusers, including central diffusers with blades that separate fresh water and pulp suspension layers, preventing mixing and maintaining turbulence only at the boundaries to ensure clear, separate liquid layers are formed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If turbulence is generated in liquid layers to improve mixing and distribution, then homogeneity of liquid distribution is improved, but layer purity and consistency deteriorate due to unwanted mixing between adjacent layers
Solution Approach 1:
A central diffuser is introduced as an intermediary element between adjacent liquid layers. This central diffuser generates turbulence that is confined to the center of the nozzle, preventing direct mixing between adjacent layers while still achieving adequate distribution. The central diffuser acts as a mediator that creates controlled chaos only where needed, maintaining layer separation at the boundaries.
Solution Approach 2:
The patent applies different flow conditions to different regions of the nozzle. Adjacent regions maintain laminar flow to preserve layer purity, while the central region experiences turbulence for improved distribution. This local differentiation of flow quality allows each region to have the appropriate characteristics for its function without compromising other regions.
2Stability of the object's composition
If multiple liquid layers are supplied separately to maintain layer purity, then layer consistency is improved, but mixing and distribution homogeneity deteriorates due to lack of turbulence
Solution Approach 1:
The nozzle is segmented into multiple independent diffusers, each handling a specific liquid layer. This segmentation allows each layer to be treated independently with appropriate flow conditions, maintaining layer purity while enabling centralized turbulence generation in the middle diffuser to improve overall distribution homogeneity.
Solution Approach 2:
Different flow regimes are applied locally to different diffusers. Central diffusers generate turbulence for improved mixing and distribution, while outer diffusers maintain laminar flow to preserve layer purity. This local quality differentiation resolves the contradiction between needing turbulence for homogeneity and maintaining separation for consistency.
3Manufacturing precision
If blades are added to separate liquid layers in the nozzle, then layer separation is improved, but device complexity increases
Solution Approach 1:
The central diffuser serves multiple functions: it generates turbulence for improved distribution, acts as a physical separator between adjacent layers, and maintains layer purity through its positioning. By making the central diffuser multi-functional, the patent reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved layer separation.
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 design allows for the formation of a three-layer fiber web with individual pure liquid surface side layers, maintaining the purity and properties of additives, reducing raw material costs, and enhancing dewatering capacity by preventing layer mixing and chemical interactions.
Implementation Method 1
a turbulence generator and a nozzle chamber having two converging walls forming a nozzle outlet. The turbulence generator has a plurality of diffusers creating turbulence in liquids supplied into each respective diffuser
Implementation Method 2
each of the diffusers having an outlet into the nozzle chamber, wherein central diffusers of the plurality of diffusers comprise a first central diffuser and a second central diffuser, the first central diffuser has two blades arranged at its outlet and extending into the nozzle chamber in a converging manner, the blades separating the fresh water, dilution water, and/or white water as the liquid flowing through the first central diffuser from the liquids flowing through adjacent diffusers
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a multilayer headbox structure for a fiber web machine for forming a fiber web, comprising a multilayer headbox having a turbulence generator and a nozzle chamber having two converging walls (21, 22) forming a nozzle outlet (24). The turbulence generator has a plurality of diffusers (1, 3, 4, 5, 7, 8, 9) creating turbulence in liquids supplied into each respective diffuser via feeding means (65, 66, 67, 68) for feeding the liquids, each of the diffusers having an outlet into the nozzle chamber, wherein central diffusers of the plurality of diffusers comprise a first central diffuser (3) and a second central diffuser (1, 7), the first central diffuser is connected with feeding means (66) feeding fresh water, dilution water, and/or white water into the first central diffuser, the first central diffuser has two blades (12, 13) arranged at its outlet and extending into the nozzle chamber in a converging manner, the blades separating the fresh water, dilution water, and/or white water as the liquid flowing through the first central diffuser from the liquids flowing through adjacent diffusers, the second central diffuser is connected with feeding means (67) feeding pulp suspension into the second central diffuser, the second central diffuser has an additional blade (14) arranged at the outlet, and the additional blade has a shorter length than the adjacent blade of the first central diffuser, and the central diffusers are arranged between a top ply diffuser (4, 5) and a back ply diffuser (8, 9), in which top ply diffuser top ply pulp suspension as the liquid flows through the top ply diffuser for forming a top ply of the fiber web and in which back ply diffuser back ply pulp suspension as the liquid flows through the back ply diffuser for forming a back ply of the fiber web.