Screw Conveyor Pulp Transport Pressure Management

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Solution Overview

Problem

Existing pulp transportation methods in pulping processes face challenges such as cavitation in pumps due to high pulp temperatures, leading to inefficient pumping and the need for cumbersome standpipes that occupy significant space.

Innovation Solution

A system comprising a receiving portion, a dilution portion, and a screw conveyor that increases pressure from the receiving portion to the dilution portion, allowing for controlled pumping by a pump connected to the dilution portion, which maintains elevated pressure and avoids cavitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standpipes are used to prevent cavitation in pumps, then pumping reliability is improved, but device complexity and space consumption increase

Engineering Contradiction:
Improvepumping reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the standpipe function (pressure maintenance) with the pump inlet directly, eliminating the need for separate tall standpipe structures. The pump is designed to draw pulp directly from the process vessel while maintaining sufficient pressure to prevent cavitation, merging two previously separate components into an integrated system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of using vertical height (5-10m standpipes) to generate pressure, the invention uses horizontal positioning and controlled pulp flow to maintain pressure. The pump is positioned to draw pulp from a specific depth in the process vessel, using the vertical distance within the vessel rather than external tall structures to generate the necessary pressure head.

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

2Reliability

If standpipes are used to prevent cavitation, then pumping reliability is improved, but space consumption increases

Engineering Contradiction:
Improvepumping reliabilityVSAvoidspace consumption
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines the standpipe function (pressure maintenance) with the pump inlet directly, eliminating the need for separate tall standpipe structures. The pump is designed to draw pulp directly from the process vessel while maintaining sufficient pressure to prevent cavitation, merging two previously separate components into an integrated system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of using vertical height (5-10m standpipes) to generate pressure, the invention uses horizontal positioning and controlled pulp flow to maintain pressure. The pump is positioned to draw pulp from a specific depth in the process vessel, using the vertical distance within the vessel rather than external tall structures to generate the necessary pressure head.

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

3Reliability

If pulp is fed to standpipes to generate pressure, then cavitation is prevented, but the arrangement becomes cumbersome and space-consuming

Engineering Contradiction:
Improvecavitation preventionVSAvoidoperational simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent combines the standpipe function (pressure maintenance) with the pump inlet directly, eliminating the need for separate tall standpipe structures. The pump is designed to draw pulp directly from the process vessel while maintaining sufficient pressure to prevent cavitation, merging two previously separate components into an integrated system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts the essential function of the standpipe (pressure generation) and integrates it directly into the pump design and process vessel configuration, removing the need for separate external standpipe structures and simplifying the overall arrangement.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution enables efficient and reliable pulp transportation by maintaining elevated pressure, preventing cavitation, and reducing the need for space-consuming standpipes, thus improving the operational efficiency and versatility of pulp mills.

Implementation Method 1

a screw conveyor for transporting pulp from the receiving portion to the dilution portion, the screw conveyor comprising a screw

Methodology Applied
Scientific EffectScrew conveyor mechanism: Screw

Implementation Method 2

an outlet connected to a pump for pumping diluted pulp from the arrangement to a subsequent process stage

Methodology Applied
Scientific EffectPumping: Pump

Data Source

PatentEP3765668B1Arrangement and method for transporting pulp from one process stage to a subsequent process stage
Publication Date: 2025.02.19 VALMET AB
  • EP3765668B1 patent drawingFigure 1
  • EP3765668B1 patent drawingFigure 2
  • EP3765668B1 patent drawingFigure 3

AI summary

The present invention relates to an arrangement for transferring pulp from one process stage to a subsequent process stage, the arrangement comprising a receiving portion for receiving pulp at a first dry solids content and a first pressure,a dilution portion for diluting pulp to a second solid content and for holding the pulp at a second pressure,and a screw conveyor for transporting pulp from the receiving portion to the dilution portion, the screw conveyor comprising a screw,wherein the screw conveyor is arranged to transport the pulp and to also increase the pressure from the first pressure to the second pressure. The invention also relates to a method for transferring pulp.