Open-Wall Screw Hub for Consistent Centrifuge Solids Discharge

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Solution Overview

Problem

Existing centrifuge screw designs face issues with limited pond depth due to buoyancy and sedimentation effects, leading to unwanted blockages and inconsistent solids discharge, particularly in solid-jacket screw centrifuges.

Innovation Solution

A screw hub design featuring a cylindrical longitudinal section with an open wall structure and a solids discharge section that deviates from a simple conical shape, such as a double truncated cone, providing increased volume and improved flow properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a simple conical shape is used for the solids discharge section, then the structure is simple and easy to manufacture, but it leads to unwanted blockages and inconsistent solids discharge

Engineering Contradiction:
Improvestructural simplicityVSAvoidsolids discharge consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The solids discharge section is segmented into multiple functional zones: a conical section for initial solids movement, a cylindrical section for consistent discharge, and an optional expansion section for high solids loads. This segmentation allows each zone to perform its specific function optimally, preventing blockages while maintaining manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design transitions from a simple 2D conical shape to a 3D composite structure combining conical, cylindrical, and expansion sections. This dimensional evolution enables control over solids flow in multiple directions, ensuring consistent discharge while accommodating complex material behavior.

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

2Productivity

If a large pond depth is desired for clarification, then separation efficiency improves, but the pond depth is limited by the diameter of the screw hub and buoyancy effects

Engineering Contradiction:
Improveclarification efficiencyVSAvoidpond depth
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The screw hub employs different structural qualities in different sections: an open-wall structure in the pond depth region to reduce buoyancy and allow greater immersion, and a closed or partially closed structure in the solids discharge section for consistent material ejection. This local differentiation enables both deep pond operation and reliable solids discharge.

Inventive Principle:
Principle #3Local quality

3Strength

If the cylindrical longitudinal section has a closed wall structure, then structural strength is maintained, but flow properties and solids discharge performance deteriorate

Engineering Contradiction:
Improvestructural strengthVSAvoidsolids discharge performance
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The cylindrical longitudinal section uses an open-wall structure specifically in regions requiring flow performance, while maintaining closed structures only where structural strength is critical. This localized application of different structural qualities optimizes both strength and discharge performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The open-wall structure creates a porous-like configuration that allows solids and fluids to pass through or around the hub, improving flow properties and discharge consistency without significantly compromising structural integrity when properly designed.

Inventive Principle:
Principle #31Porous materials

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

Enhances solids discharge by reducing bottlenecks, ensuring a relaxed state of solids, minimizing lump formation, and improving wear resistance, allowing for high solids loads and gentle processing of abrasive media.

Implementation Method 1

The drum is rotated at high speed, allowing a multiphase mixture inside to be separated into at least a heavy phase and a light phase

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the screw is mounted so that it can rotate within the drum and has a helix. The helix is arranged around a screw hub. The screw helix travels along the inner surface of the drum, conveying the heavier phase material to an axial end of the drum

Methodology Applied
Scientific EffectHelical conveyance: Helix

Implementation Method 3

the pond depth is limited by the diameter of the screw hub and the resulting buoyancy and sedimentation effects of the mixture or light phase being clarified

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 4

the pond depth is limited by the diameter of the screw hub and the resulting buoyancy and sedimentation effects of the mixture or light phase being clarified

Methodology Applied
Scientific EffectSedimentation: Sedimentation

Data Source

PatentEP4240534B1Screw hub, centrifugal screw, and solid bowl screw centrifuge
Publication Date: 2026.02.18 FLOTTWEG GMBH & CO KGAA
  • EP4240534B1 patent drawingFigure 1~2

AI summary

The invention relates to a screw hub (10) for a centrifugal screw (80), said screw hub (10) having, in the longitudinal direction (R), at least one cylindrical longitudinal portion (11) and a portion (12) at the solid-discharge end, the cylindrical longitudinal portion (11) having an open wall structure (40), and the portion (2) at the solid-discharge end having an at least partly closed shape that differs from a simple conical shape.