Pulp Distribution Device with Local Throttle for Washing Apparatus

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Solution Overview

Problem

Existing pulp washing and dewatering apparatuses face challenges in uniform pulp distribution along the length of press rolls, leading to inefficiencies and potential plugging issues at the ends of the rolls, which affects the capacity and effectiveness of the washing process.

Innovation Solution

A pulp distribution device with a local throttle mechanism in the pulp transportation chamber near the outlet, ensuring the device operates completely filled, with adjustable throttle gap width to maintain internal pressure and prevent plugging, allowing for better pulp web formation and dewatering across the entire press roll length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a rotating screw distribution device is used to distribute pulp along the press roll, then the pulp can be distributed lengthwise onto the press rolls, but the end parts of the press rolls may operate without pulp

Engineering Contradiction:
Improvepulp distribution coverageVSAvoidwashing apparatus capacity
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The invention changes the geometric parameters of the distribution device by extending it beyond the press roll ends and configuring the screw flights to extend along the entire length of the distribution device, ensuring pulp reaches the end portions of the press rolls for complete coverage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The distribution device is extended in the longitudinal dimension beyond the press roll ends, creating an overflow configuration where pulp can flow onto the end portions of the press rolls from the extended distribution device

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If holes are arranged along the generator of the inlet box to distribute pulp, then uniform distribution along the width of the pulp web is achieved, but the holes have a tendency to plug

Engineering Contradiction:
Improvepulp web uniformityVSAvoiddistribution device reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention removes the problematic holes from the distribution device design and replaces them with a screw conveyor mechanism that distributes pulp through its rotational motion and flight configuration, eliminating the plugging issue while maintaining distribution function

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the hole-based passive distribution system with an active mechanical screw conveyor system that uses rotational mechanical action to distribute pulp uniformly along the press roll width

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the press roll rotation speed is increased to提高 capacity, then the washing apparatus processes more pulp, but the pulp web formation becomes less smooth and may be torn

Engineering Contradiction:
Improvewashing apparatus capacityVSAvoidpulp web smoothness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The distribution device is designed to establish complete and uniform pulp coverage on the press rolls before the rolling action begins, ensuring that even at high rotation speeds, the pulp web is properly formed from the start without tearing

Inventive Principle:
Principle #10Preliminary action

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

The solution ensures a higher capacity and smoother pulp web formation, independent of press roll rotation speed, with improved washing efficiency and reduced risk of plugging, resulting in enhanced pulp distribution and dewatering performance.

Implementation Method 1

maintain internal pressure

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

a rotatable distribution means in the form of a screw rotating in a direction of rotation D2

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

pressed in a nip 23

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 4

perforated outer surfaces 21

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2943613B1An apparatus for washing and/or dewatering of cellulose pulp
Publication Date: 2019.09.25 VALMET AB
  • EP2943613B1 patent drawingFigure 1
  • EP2943613B1 patent drawingFigure 2
  • EP2943613B1 patent drawingFigure 3

AI summary

The invention relates to an apparatus (100) for washing and/or dewatering of cellulose pulp, which apparatus (100) comprises a first movable permeable surface (21); a pulp transportation chamber wall (22) and a pulp transportation chamber (25), which pulp transportation chamber (25) has a chamber gap width (Wv) between the pulp transportation chamber wall (22) and the first movable permeable surface (21); and a pulp distribution device (10) comprising an inlet (11) and an outlet (12), which pulp distribution device (10) is arranged to distribute pulp through its outlet (12) onto the first movable permeable surface (21).According to the invention the pulp transportation chamber (25) is provided with a local throttle (31) having a throttle gap width (Wt), near the outlet (12) of the pulp distribution device (10),and in that a second permeable surface (14) for initial dewatering is provided before the local throttle (31).