Arched Accept Tank Mixer Axle Angling for Fiber Suspension

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Solution Overview

Problem

Existing mixing systems in accept tanks for pulped fiber suspensions in the papermaking industry create excessive turbulence, uneven flow patterns, and particle precipitation, leading to inefficient energy consumption and accumulation of particles, necessitating frequent process interruptions.

Innovation Solution

The accept tank design features two arched ends with curved sidewalls and an elongated section, equipped with mixers having axles angled away from the centerline to direct flow towards the sidewall, and a flat bottom to minimize turbulence, along with strategically positioned outlets to maintain stable, coherent flow and prevent particle precipitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If propellers of mixers are positioned to create strong mixing action, then mixing effectiveness is improved, but turbulence and particle precipitation increase

Engineering Contradiction:
Improvemixing effectivenessVSAvoidturbulence and particle precipitation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by positioning mixers at specific locations (arched ends) and orienting their axles at specific angles (15-30 degrees from centerline) to create appropriate flow patterns in different regions of the tank. This localized positioning and angling ensures effective mixing while preventing excessive turbulence and particle precipitation in critical areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes key parameters including mixer axle angle (15-30 degrees from centerline), propeller diameter (10-20% of tank width), and mixer positioning (within arched ends) to optimize the balance between mixing effectiveness and flow stability. These parameter adjustments create stable coherent flow while maintaining adequate mixing action.

Inventive Principle:
Principle #35Parameter changes

2Speed

If mixers are positioned to create strong flow, then mixing speed is improved, but energy consumption increases

Engineering Contradiction:
Improvemixing speedVSAvoidenergy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent utilizes the curved geometry of the arched ends and the angled orientation of mixer axles to create coherent circular flow patterns that efficiently utilize the tank's shape. This geometric alignment allows mixers to generate stable flow with less energy input compared to straight-tanked configurations or perpendicular mixer positioning.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent optimizes energy efficiency by adjusting mixer parameters including axle angle (15-30 degrees), propeller diameter (10-20% of tank width), and positioning within arched ends. These parameter changes create stable flow patterns that maintain mixing speed while reducing excessive turbulence and energy consumption.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If propellers are aligned to point at tank center, then flow symmetry is improved, but particle accumulation at bottom increases

Engineering Contradiction:
Improveflow symmetryVSAvoidparticle accumulation
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent deliberately introduces asymmetry by positioning mixers within the arched ends and angling their axles 15-30 degrees from the tank centerline. This asymmetric positioning creates a balanced circular flow pattern that prevents dead zones and particle accumulation at the bottom, while maintaining overall flow symmetry through the paired mixer configuration.

Inventive Principle:
Principle #4Asymmetry

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 stable, energy-efficient mixing with reduced particle accumulation and precipitation, enhancing operational continuity and reducing energy consumption.

Implementation Method 1

The propellers of the mixers should have a diameter which is from 10% to 20% of the width of the tank for creating suitable sized wide flow

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

Simulations and practice have revealed that prior art positions and alignments of propellers of mixers within an accept tank will create excess turbulence

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 3

The tank may or may not aim to separate heaviest particles like sand or glass to the bottom of the tank

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP4347948B1Accept tank mixing arrangement
Publication Date: 2025.07.02 ANDRITZ OY
  • EP4347948B1 patent drawingFigure 1~2

AI summary

The invention is an accept tank arrangement for mixing of pulped fiber suspension without causing precipitation or accumulations to the bottom tank. The accept tank has sidewalls (3,4) which have a form of two opposite arched ends (2) and an elongated section (1) between the arched ends (2). The accept tank has at least two mixers (10), and at least one of the mixers (10) are located within the arched end (2). The mixers (10) have propellers (12) at ends of their axles (11). For best performance at least two of the axles (11) of the mixers (10) are horizontally aligned to the direction of the elongated section (1) and the center line of at least one axle (11) of the mixer (10) is aimed at a point, which is at the sidewall (3) of the elongated section (1) at least 25% of the length of the elongated section (1) away from the beginning of the elongated section (1). Preferably the propellers (12) are positioned and/or aligned symmetric with respect to the centerpoint of the accept tank. Within the center of the elongated section is an elongated centerpiece (6) having rounded ends. The accept tank has a substantially flat bottom at least at the elongated section (1) of the accept tank.