Disc Filter Receiver Chute Relocation for Fibre Thickening

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Solution Overview

Problem

Conventional disc filters face challenges in dewatering cellulose fibre suspensions with low dewatering resistance and high fibre concentration, leading to undesired thickening and reduced dewatering capacity, particularly when receiver chutes are located on the side of the rotor shaft where filter sectors move upwards, causing fibre material to be torn off and deposited in the suspension.

Innovation Solution

The receiver chutes are relocated to the side of the rotor shaft where filter sectors move downwards, allowing fibre material to be diluted with flushing liquid and extending the drying phase, while inlet openings are positioned above the suspension to align with the flow induced by rotating filter elements, reducing the formation of thickenings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If receiver chutes are located on the side where filter sectors move upwards, then fibre material can be received, but fibre material is torn off and deposited in the suspension causing thickening

Engineering Contradiction:
Improvefibre material receptionVSAvoidthickening of suspension
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The receiver chutes are relocated from the upward-moving side to the downward-moving side of the filter sectors. This inversion of the receiver chute position eliminates the harmful effect of fibre material being torn off and deposited in the suspension, as the fibre material is now received during the downward movement when it is already separated from the suspension flow

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-generated harmful factors

If receiver chutes are relocated to the downward side, then thickening is prevented, but fibre material needs to be diluted to desired dry content

Engineering Contradiction:
Improvethickening preventionVSAvoidfibre material concentration
Core Design Contradiction:
Object-generated harmful factorsVSQuantity of substance

Solution Approach 1:

Flushing liquid is introduced as an intermediary substance to dilute the fibre material in the receiver chutes to the desired dry content. The flushing liquid acts as a mediator between the concentrated fibre material and the final product, allowing control over the dry content while preventing thickening in the suspension

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If inlet openings are positioned above suspension, then thickening is reduced, but alignment with flow induced by rotating filter elements is required

Engineering Contradiction:
Improvethickening reductionVSAvoidinlet positioning alignment
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The inlet openings are positioned at specific locations above the suspension level, creating a localized flow introduction point that aligns with the flow induced by the rotating filter elements. This local positioning optimizes the flow pattern and reduces thickening without requiring complex overall system changes

Inventive Principle:
Principle #3Local quality

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 enhances dewatering efficiency, maintains high fibre concentration, and prevents fibre material from being torn off, thereby improving dewatering capacity and reducing thickening tendencies, allowing for a more compact and cost-effective disc filter operation.

Implementation Method 1

water is sucked from the suspension, through the filtering lining on the filter sectors and into the flow channels inside the filter sectors, while fibre material is deposited as a fibre cakes on the external surfaces of said filtering lining

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 2

water is sucked from the suspension, through the filtering lining on the filter sectors and into the flow channels inside the filter sectors

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 3

the continued suction through the filtrate channels in the rotor shaft and the flow channels in the filter sectors will create an air flow through the fibre cakes deposited on the filtering lining of the filter sectors

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

the continued suction through the filtrate channels in the rotor shaft and the flow channels in the filter sectors will create an air flow through the fibre cakes deposited on the filtering lining of the filter sectors

Methodology Applied
Scientific EffectAir flow: Convection

Implementation Method 5

The filter sectors will then successively rotate past loosening members in the form of spray nozzles, which direct jets of water or any other suitable fluid towards the fibre cakes to thereby loosen the fibre cakes from the filtering lining of the filter sectors

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 6

the filter sectors are successively cleaned by means of flush liquid emitted from cleaning members in the form of spray nozzles

Methodology Applied
Scientific EffectHydraulic flushing: Fluid Spray

Data Source

PatentEP2582441B1Disc filter
Publication Date: 2019.08.07 RIOKS PATENTER
  • EP2582441B1 patent drawingFigure 1
  • EP2582441B1 patent drawingFigure 2
  • EP2582441B1 patent drawingFigure 3

AI summary

A disc filter for dewatering cellulose fibre suspensions comprising disc-shaped filter elements (11) carried by a rotor shaft (7) in order to rotate inside a vessel (2) while being partly immersed in a suspension received in the vessel. Each filter element comprises several filter sectors (12) distributed about the rotor shaft. Loosening members (25) are provided for loosening fibre material that has been filtered out of the suspension and deposited on a filtering lining (13) of the respective filter element. Receiver chutes (30) are located in the part of the vessel where the filter sectors (12) are rotated down into the suspension from a position above the suspension. The receiver chutes receive loosened fibre material together with flushing liquid from cleaning members (26) located above the receiver chutes to thereby allow the fibre material to be diluted in the receiver chutes to a desired dry content by means of this flushing liquid.