Dual-Flight Conveyor Screw for Decanter Centrifuge Oil Release

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing decanter centrifuge conveyor screws are not optimal for oil release, particularly from solids, leading to inefficiencies in oil extraction processes.

Innovation Solution

A conveyor screw design featuring a central body with two flights: a first flight with a pitch angle less than 20° for longitudinal conveying and a second flight with a pitch angle greater than 30° for spreading out the slurry, enhancing oil release from solids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If a conventional conveyor screw with single flight design is used, then the device complexity is low, but the oil release from solids is insufficient

Engineering Contradiction:
Improveoil release from solidsVSAvoidconveyor screw structure
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The conveyor screw is segmented into two distinct flights with different pitch angles. The first flight has a pitch angle of 10-20° for conveying slurry axially, while the second flight has a pitch angle of 30-45° for spreading slurry radially. This segmentation allows each flight to perform its specific function optimally, thereby increasing oil release from solids without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the conveyor screw are given different local qualities through the two flights. The first flight region is optimized for axial conveying with a lower pitch angle, while the second flight region is optimized for radial spreading with a higher pitch angle. This local differentiation enhances oil release efficiency by addressing different separation needs at different locations

Inventive Principle:
Principle #3Local quality

2Productivity

If the pitch angle is increased to spread out slurry for better oil release, then the oil extraction efficiency improves, but the longitudinal conveying capability decreases

Engineering Contradiction:
Improveoil extraction efficiencyVSAvoidlongitudinal conveying speed
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

The conveyor screw is divided into two flights with different pitch angles to separate the functions of longitudinal conveying and radial spreading. The first flight with pitch angle 10-20° handles axial conveying, while the second flight with pitch angle 30-45° handles radial spreading. This segmentation resolves the contradiction by assigning different pitch angles to different functional segments

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dual-flight conveyor screw design makes the single screw structure multi-functional. The first flight provides longitudinal conveying capability while the second flight provides radial spreading capability. Both functions are achieved within a single conveyor screw component, maintaining productivity without sacrificing conveying speed

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 combination of the first and second flights increases oil release from solids, allowing for more efficient oil extraction and collection at the light phase outlet.

Implementation Method 1

a conveyor screw (14) having a central body (28) and comprising a first flight (32) being attached to the central body (28) and extending in the longitudinal direction

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

Centrifugal based methods, and in particular decanter centrifuges, can be used for separating the oil and fat from the residual solids and liquids

Methodology Applied
Scientific EffectCentrifugal Force: Centrifugal Force

Data Source

PatentEP4563233A1A decanter centrifuge for separating feed material
Publication Date: 2025.06.04 ALFA LAVAL CORP AB
  • EP4563233A1 patent drawingFigure 1A
  • EP4563233A1 patent drawingFigure 1B
  • EP4563233A1 patent drawingFigure 2A~2C

AI summary

The present invention relates to a conveyor screw for a decanter centrifuge. The conveyor screw defines a cylindrical portion and a conical portion and comprises a central body. The conveyor screw defines a first flight attached to the central body. The first flight defines a first diameter and a pitch angle being less than 20°. The conveyor screw further defines a second flight attached to the central body. The second flight has the same winding direction as the first flight and being at least partially intertwined with the first flight. The second flight defines a pitch angle being greater than 30° and the second diameter being smaller than the first diameter.