Bi-directional Dilution Hydrocyclone for Fiber Suspension Clogging

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Solution Overview

Problem

Hydrocyclones face issues with the heavy fraction thickening and clogging due to its smaller flow rate compared to the light fiber fraction, leading to reduced separation efficiency and increased fiber loss in the reject fraction.

Innovation Solution

A distribution head with a nozzle design that splits the fluid jet into two flow components, one directed towards the base end and the other towards the apex end of the separation chamber, creating a pressure gradient and pulsating action to reduce fiber thickening and improve separation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional single-direction dilution device is used, then the structure is simple, but the heavy fraction thickens and clogs due to insufficient fluid circulation

Engineering Contradiction:
Improveclogging resistanceVSAvoidnozzle structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The single outlet passage is divided into two separate outlet passages (first and second outlet passages) that spray fluid in opposite directions. This segmentation allows the dilution fluid to circulate through both ends of the separation chamber, preventing thickening and clogging in the heavy fraction without requiring complex additional components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dilution fluid is directed not only axially but also radially outward through the outlet passages positioned at opposite ends of the distribution head. This multi-dimensional spray pattern enhances fluid circulation and prevents clogging more effectively than conventional single-direction spraying

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

2Loss of substance

If dilution water is supplied to reduce thickening, then fiber loss in reject fraction is reduced, but plugging issues occur with conventional nozzle designs

Engineering Contradiction:
Improvefiber lossVSAvoidplugging resistance
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The two outlet passages create a dynamic pulsating action by spraying fluid alternately towards opposite ends of the separation chamber. This dynamic circulation pattern prevents stagnant zones where plugging could occur, while efficiently reducing fiber loss through controlled dilution

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The opposing spray directions create periodic fluid movement patterns that continuously refresh the heavy fraction flow path. This periodic action prevents plugging by ensuring continuous fluid motion through the separation chamber, allowing effective dilution without clogging

Inventive Principle:
Principle #19Periodic action

3Reliability

If the heavy fraction flow rate is increased to prevent clogging, then separation efficiency improves, but fiber loss in accept fraction increases

Engineering Contradiction:
Improveseparation efficiencyVSAvoidfiber loss in accept fraction
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The dilution fluid is selectively applied at specific locations (opposite ends of the separation chamber) where it is most needed to prevent heavy fraction thickening. This localized application prevents clogging in the heavy fraction outlet while minimizing disruption to the accept fraction separation process

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

The improved nozzle design significantly reduces thickening by up to 30% while maintaining separation efficiency, even with high concentrated suspensions, and allows for a wider range of dilution water usage, reducing plugging issues and enhancing treatment quality.

Implementation Method 1

creating a pressure gradient and pulsating action

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

the fiber suspension flows in a vortex in the separation chamber

Methodology Applied
Scientific EffectVortex flow: Vortex Ring

Implementation Method 3

a liquid hydrocyclone separator is known comprising an axially elongated chamber

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentEP3018252B1Hydrocyclone with a bi-directional dilution device
Publication Date: 2020.01.22 OVIVO LUXEMBOURG R L
  • EP3018252B1 patent drawingFigure 1~4
  • EP3018252B1 patent drawingFigure 5~6
  • EP3018252B1 patent drawingFigure 7~8

AI summary

Disclosed is a hydrocyclone for separating a fiber suspension into a heavy fraction substantially containing heavy contaminants and a light fiber fraction substantially containing fibers, comprising a housing (4) with a circumferential wall (8), which defines an elongated separation chamber (6) with two opposite ends (14, 16) and with a center axis (17) extending between the opposite ends, an inlet member (18) for supplying the fiber suspension substantially tangentially into the separation chamber at one end (14) thereof, so that the fiber suspension flows in a vortex in the separation chamber, a first outlet member (20) for discharging the accept fraction from the separation chamber at said one end, a second outlet member (22) for discharging the heavy fraction from the separation chamber at the other end (16) thereof, and a distribution head (36') for supplying a fluid to the separation chamber, which distribution head is situated centrally in the separation chamber relatively close to said other end and having at least one outlet passage (60, 64', 64", 64''') designed for spraying a fluid jet, the fluid jet having a flow component in the direction towards the other end of the separation chamber, and the fluid jet having another flow component directed towards the one end.