Attritor Mill Rotor Layout for Organic Waste Grinding Flow

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Solution Overview

Problem

Existing attritor mills are inefficient in processing organic waste, plastics, and fibrous materials due to suboptimal material flow and grinding pebble trajectories.

Innovation Solution

The attritor mill design features a rotor with radially extending arms of varying lengths, supporting protrusions on the bottom wall, and blades to enhance material agitation and flow, along with adjustable outlet actuators for optimized processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional attritor mills are used with simple rotor design, then device complexity is low, but material flow efficiency and grinding pebble trajectories are insufficient

Engineering Contradiction:
Improvematerial processing efficiencyVSAvoidrotor structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The rotor is segmented into multiple arms of varying lengths arranged at different radial positions, with each arm having specific grinding bodies attached. This segmentation allows different parts of the rotor to perform different functions - shorter arms for intense local grinding and longer arms for broader material distribution, thereby improving overall material processing efficiency without creating a monolithic complex structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the rotor have different properties - the arms are positioned at varying radial distances from the rotation axis, with each region containing specific types of grinding bodies suited to local requirements. This creates zones of different grinding intensity and material flow characteristics, optimizing processing efficiency while maintaining structural coherence.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If grinding pebbles are used in conventional attritor mills, then material can be ground through impacts, but the trajectories and flow patterns are not optimal for organic waste, plastics, or fibrous materials

Engineering Contradiction:
Improveparticle size uniformityVSAvoidmaterial flow efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The rotor arms are designed with asymmetric length configurations, where not all arms are of equal length. This asymmetry creates varied impact trajectories for the grinding pebbles as they rotate, ensuring that material receives consistent grinding action from multiple angles and heights, thereby improving particle size uniformity while enhancing material flow efficiency through more dynamic pebble trajectories.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention introduces vertical dimensionality to the grinding process by positioning grinding bodies at different radial heights and using arms of varying lengths. This multi-dimensional arrangement creates three-dimensional impact patterns rather than simple horizontal circular trajectories, improving both particle size reduction consistency and material flow characteristics through enhanced vertical mixing and distribution.

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

3Ease of manufacture

If the grinding chamber has fixed structure, then manufacturing is simple, but maintenance and cleaning are difficult

Engineering Contradiction:
Improvegrinding chamber constructionVSAvoidmaintenance accessibility
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The grinding chamber is divided into separable components including the rotor assembly, housing, and grinding body containers. This segmentation allows individual parts to be easily removed, cleaned, and replaced without disassembling the entire structure, maintaining manufacturing simplicity while dramatically improving maintenance accessibility and operational flexibility.

Inventive Principle:
Principle #1Segmentation

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

Improves the efficiency of material processing by ensuring uniform particle size and easier flow within the grinding chamber, reducing wear, and facilitating quick maintenance.

Implementation Method 1

causing the rotor (11) rotate on itself so that its arms (15, 17) strike the grinding free bodies (19) and at least a part of the latter bounce against the walls of the grinding chamber (7)

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

its arms (15, 17) strike the grinding free bodies (19) and at least a part of the latter bounce against the walls of the grinding chamber (7) and other grinding free bodies (19), and/or strike the material to be treated

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 3

The attritor mill (1) is configured for grinding, reducing, mincing or micronizing a material to be treated... carrying out the following steps: D.1) mixing the material to be treated with a plurality of grinding free bodies (19) in the grinding chamber (7)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4507828B1Attritor mill and process for processing a material therewith
Publication Date: 2026.03.11 ATTRITOR MILL LTD
  • EP4507828B1 patent drawingFigure 1
  • EP4507828B1 patent drawingFigure 2
  • EP4507828B1 patent drawingFigure 2A

AI summary

The attritor mill (1) according to the invention 5 comprises a grinding container (5) and a rotor (11) comprises a plurality of arms (15, 17). The attritor mill (1) is configured for grinding, reducing, mincing or micronizing a material to be treated such as, for example, solid urban waste, food waste, mowing or pruning scraps, vegetable waste from agricultural activity, waste similar to urban waste, FOS ("dry organic fraction") of urban waste carrying out the following steps: D.1) mixing the material to be treated with a plurality of grinding free bodies (19) in the grinding chamber (7); D.2) agitating the material to be treated and the plurality of grinding free bodies (19) by causing the rotor (11)rotate on itself. At least one first arm (15) closest to the bottom wall (21) is shorter than at least one second arm (17) arranged above said first arm (15).