Headbox Intermediate Channel Design for Fiber Suspension Distribution
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Solution Overview
Problem
Existing headboxes for producing fibrous webs, such as paper or cardboard, face issues with high pressure loss, energy consumption, unstable fiber orientation, and excessive use of chemicals due to complex recirculation systems and tapered cross-sections, leading to inefficiencies and maintenance challenges.
Innovation Solution
A headbox design with a system pressure loss consisting of a first pressure loss between the feed device and intermediate channel, and a second pressure loss in the turbulence-generating means, featuring a cross-sectional ratio between inlet and intermediate channel that optimizes fibrous suspension distribution, eliminates recirculation, and incorporates hydraulic elements for pressure recovery, along with adjustable dosing systems for fluid distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a recirculation system is used to control pressure and flow in the headbox, then pressure distribution can be maintained, but device complexity and operational costs increase significantly
Solution Approach 1:
The invention extracts and eliminates the recirculation system from the headbox design. By removing the feedback line, flow control valves, sensors, and actuators, the patent achieves pressure distribution through optimized hydraulic geometry alone - specifically through the intermediate channel dimensions and turbulence generator configuration, thereby simplifying the system while maintaining functional performance.
Solution Approach 2:
The headbox system is designed to self-regulate pressure distribution without external control systems. The intermediate channel with specific dimensions (width 0.3-1.5 times the turbulence generator width, length 0.5-2.0 times the width) and the turbulence generator configuration create inherent flow stabilization that eliminates the need for active recirculation control.
2Stability of the object's composition
If a tapered cross-section is used in the transverse distribution pipe to improve flow distribution, then suspension distribution improves, but energy consumption increases
Solution Approach 1:
The invention changes the geometric parameters of the headbox components - specifically using a parallel cross-section in the transverse distribution pipe instead of a tapered one, and optimizing the intermediate channel dimensions (width 0.3-1.5 times turbulence generator width, length 0.5-2.0 times width). These parameter changes achieve stable fiber orientation distribution without the energy penalty of tapered sections.
Solution Approach 2:
The intermediate channel acts as a mediator between the transverse distribution pipe and the turbulence generator. By providing a transition zone with optimized dimensions, it enables smooth flow distribution and fiber orientation stabilization without requiring energy-intensive tapered sections in the distribution pipe.
3Stability of the object's composition
If the intermediate channel length is increased to improve suspension distribution, then flow uniformity improves, but pressure loss increases
Solution Approach 1:
The invention optimizes the intermediate channel length parameter to a specific range (0.5-2.0 times the turbulence generator width) rather than simply increasing it indefinitely. This parameter optimization achieves uniform suspension distribution while limiting pressure loss through the balanced dimensional relationship between channel length, width, and turbulence generator dimensions.
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 achieves consistent fibrous suspension inflow, reduced energy consumption, improved fiber orientation stability, and lower chemical usage, resulting in a more efficient and cost-effective production process with enhanced web quality.
Implementation Method 1
In the subsequent turbulence-generating means, the flow, ie at least the fibrous stock suspension, is equalized, any added dilution water, in particular white water, is mixed in and the entire suspension is fluidized.
Implementation Method 2
in the headbox nozzle, the suspension is accelerated to machine speed
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to a headbox (1) for a machine for producing a fibre-material web (3), in particular a paper web, cardboard web or packing-paper web, from at least one fibre-material suspension (2), having a feed arrangement (4), which feeds the at least one fibre-material suspension (2) and comprises a transverse distributing tube (4.1), having a perforated distributor tube plate (5), which follows the feed arrangement downstream and has a multiplicity of flow channels (6) arranged in lines (Z; Z1 to Z5) and in columns (S), having an intermediate channel (7), which is located downstream of the perforated distributor tube plate and extends over the width (B) of the headbox (1), having a downstream turbulence generator (8), with a multiplicity of flow channels (9) arranged in lines (Z) and in columns (S; S1 to S4), and having a headbox nozzle (11), which immediately follows the turbulence generator (8) and has a nozzle gap (12). The headbox (1) according to the invention is characterized in that a system pressure loss (ps) is provided, this being made up substantially of a first pressure loss (p1) between the feed arrangement (4, 4.1) and the intermediate channel (7) and a second pressure loss (p2) in the turbulence generator (8), wherein the first pressure loss (p1) assumes a value of from 15 to 85%, preferably of from 25 to 85%, in particular of from 40 to 85%, in that the intermediate channel (7), which is arranged between the perforated distributor tube plate (5) and the turbulence generator (8), has a free intermediate-channel length (7.L) of = 50 mm, preferably of = 120 mm, in particular of = 200 mm and in that the cross-sectional ratio (Q) between the infeed (4.Z) and an intermediate channel (7) assumes a value from 0.1 to 2, preferably from 0.15 to 1.5, in particular from 0.2 to 1.