Vertical Screw Mixer With Sleeve for Viscous Media Defibrating

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Solution Overview

Problem

Existing mixing devices for biogas plants struggle with inefficient mixing times and often fail to effectively separate solids from highly viscous media, leading to clogging and inadequate homogeneity.

Innovation Solution

A mixing device featuring a vertical screw mixer with a freely suspended sleeve and adjustable rotation direction, combined with a minimal gap between the agitator screw and sleeve, and additional features like teeth or cams to break up clumps, along with a silo-like container and screen for solid separation, and temperature control channels for sanitization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional agitators are used for mixing highly viscous media, then mixing is possible, but mixing time is excessive and homogeneity is insufficient

Engineering Contradiction:
Improvemixing timeVSAvoidhomogeneity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The mixing device segments the mixing action into two distinct components: a vertical screw mixer for rapid initial mixing and circulation, and a horizontal ribbon mixer for gentle final homogenization. This segmentation allows each mixer to perform its optimal function, reducing overall mixing time while achieving superior homogeneity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device employs dynamic control by enabling independent operation of the vertical screw mixer and horizontal ribbon mixer. The vertical screw can operate alone for rapid mixing, the ribbon mixer can operate alone for gentle homogenization, or both can operate simultaneously, providing dynamic adaptability to different mixing requirements and significantly reducing mixing time

Inventive Principle:
Principle #15Dynamics

2Reliability

If solids are present in highly viscous media, then clogging occurs with conventional mixers, but effective solid separation is needed

Engineering Contradiction:
Improveclogging preventionVSAvoidsolid separation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The device extracts the solid separation function from the mixing process by incorporating a separate screening system with a screen at the discharge end of the vertical screw mixer. Solids are separated from the viscous media before discharge, preventing clogging in downstream equipment while maintaining continuous operation and productivity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The vertical screw mixer acts as an intermediary device that both mixes the viscous media and prepares it for separation by conveying it to the screen. The screen then mediates the separation between solids and liquid, with the separated liquid returning to the mixing chamber and solids being discharged separately, thus preventing clogging while maintaining productivity

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If sanitization is required for highly viscous media, then conventional heating methods are insufficient, but effective temperature control is needed

Engineering Contradiction:
Improvesanitization effectivenessVSAvoidenergy consumption for heating
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The vertical screw mixer serves multiple functions: it mixes the viscous media, conveys it for separation, and simultaneously acts as a heating element through its heated jacket. This multi-functionality enables effective sanitization through direct contact heating while reducing overall energy consumption compared to separate heating systems

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

Solution Approach 2:

The vertical screw mixer performs self-heating through its integrated heated jacket, eliminating the need for separate external heating equipment. The media is heated directly during the mixing and conveying process, making the system self-sufficient for sanitization while minimizing energy consumption

Inventive Principle:
Principle #25Self-service

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

Achieves faster and more homogeneous mixing, effective solid separation, and enhanced sanitization, reducing clogging risks and improving overall process efficiency.

Implementation Method 1

the agitator is arranged as a vertical screw mixer in the container, wherein the screw mixer has a stirring screw and a sleeve enclosing the stirring screw

Methodology Applied
Scientific EffectScrew mixing: Screw

Implementation Method 2

The screw mixer itself can be heated by a heated jacket, which offers significant advantages. This enables a sanitization process to take place in the mixing device

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

Furthermore, it is also possible to arrange a screen at the discharge end of the screw mixer, which has the advantage that solids are separated out in the mixing device itself

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 4

Clumps, thickened portions, or similar materials can be forced into the sleeve due to the minimal gap between the outer surface of the agitator screw and the inner surface of the sleeve due to the centrifugal force when the agitator screw is driven

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4397404B1Mixing device with screw drive for defibrating
Publication Date: 2025.09.03 PUWE GMBH
  • EP4397404B1 patent drawingFigure 1
  • EP4397404B1 patent drawingFigure 2
  • EP4397404B1 patent drawingFigure 3~4

AI summary

The present invention relates to a mixing device (1) for mixing highly viscous media, in particular for a biogas plant, comprising a large-volume outer container (2) and an agitator arranged therein, wherein the container (2) has a medium inlet and a discharge line (6) for discharging the mixed medium. The agitator is designed as a vertical screw mixer (8), comprising a stirring screw (12) and a sleeve (9) enclosing the stirring screw (12).