Multi-Screw Pressing Device with Scraper Bowls for Liquid Separation

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Solution Overview

Problem

Existing pressing devices with a single screw conveyor are inefficient in separating liquid and solid components, as liquid components near the screw shaft cannot escape through the strainer basket openings, leading to incomplete separation and reduced material volume flow.

Innovation Solution

A pressing device with at least two screw conveyors arranged one behind the other on a common screw shaft, featuring a hollow cylindrical strainer basket with a pressure zone between the screws, where scraper bowls are used to guide and mix the material, ensuring liquid separation and increased pressing pressure without compromising material throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single screw conveyor is used in the pressing chamber, then the device structure is simple, but liquid components near the screw shaft cannot escape through the strainer basket openings, resulting in incomplete separation

Engineering Contradiction:
Improveseparation efficiencyVSAvoidscrew conveyor configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The single screw conveyor is divided into multiple screw conveyors (at least two) arranged one behind the other on a common screw shaft. This segmentation allows different zones of the pressing chamber to handle material differently, enabling liquid components to be effectively separated through the strainer basket openings while maintaining structural organization.

Inventive Principle:
Principle #1Segmentation

2Stress or pressure

If the cross-sectional area of the screw flight is decreased from inlet to outlet to ensure optimal squeezing, then pressing pressure is improved, but material flow rate is reduced

Engineering Contradiction:
Improvepressing pressureVSAvoidmaterial flow rate
Core Design Contradiction:
Stress or pressureVSProductivity

Solution Approach 1:

The pressing chamber is divided into multiple pressure zones by arranging several screw conveyors in sequence. Each screw conveyor maintains its own screw flight cross-sectional area, creating distributed pressure zones that collectively achieve high pressing pressure while maintaining overall material flow rate through parallel processing paths.

Inventive Principle:
Principle #1Segmentation

3Reliability

If scraper bowls are added to guide and mix material in the pressure zone, then separation efficiency and pressing pressure are improved, but device complexity increases

Engineering Contradiction:
Improveseparation efficiencyVSAvoidpressing device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The scraper bowls serve multiple functions simultaneously: they guide material flow into the pressure zone, mix the pressed material to enhance liquid-solid separation, and apply additional pressing pressure. This multi-functionality improves separation efficiency without requiring separate dedicated components for each function.

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

Enhances the separation efficiency of liquid and solid components, allowing for complete drainage of liquids and maintaining material flow, while increasing pressing pressure and preventing material jamming, thus improving the overall efficiency of the pressing process.

Implementation Method 1

at least two pressing and conveying screws arranged one behind the other are rotatable on a screw shaft

Methodology Applied
Scientific EffectScrew conveying: Screw

Implementation Method 2

the strainer rods are arranged with gap-like spacing relative to each other

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

the fluids contained in the incoming substances are squeezed out by the pressing action between the boundary surfaces of the screw flights of the conveyor screw and the strainer rods

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3838577B1Method and device for pressing
Publication Date: 2024.05.08 HARBURG FREUDENBERGER MASCHINENBAU GMBH
  • EP3838577B1 patent drawingFigure 1~2
  • EP3838577B1 patent drawingFigure 3
  • EP3838577B1 patent drawingFigure 4

AI summary

The invention relates to a pressing device comprising a strainer basket (3) and at least two conveying screws arranged one behind the other in the conveying direction on a common screw shaft, wherein a pressure zone without screw flights is arranged between the conveying screws. In the area of ​​the pressure zone, the pressing device according to the invention has a plurality of scraper trays (10) which enable an improved efficiency of the pressing process.